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World Literature Review
THE AMERICAN JOURNAL OF GASTROENTEROLOGY © 2000 by Am. Coll. of Gastroenterology Published by Elsevier Science Inc.
Vol. 95, No. 5, 2000 ISSN 0002-9270/00/$20.00 PII S0002-9270(00)00825-X
WORLD LITERATURE REVIEW Editor: David Johnson, M.D., F.A.C.G. REVIEW PANEL Jamie Barkin David Bjorkman Cedric Bremner William Carey Donald J. Clement Harold Conn Jack DiPalma Mark Fendrick M. Brian Fennerty
Mark Flemmer Norman Gitlin Christopher Gostout Robert Hawes Jorge Herrera Brenda Hoffman John Johanson Philip Katz Timothy Koch
Mark Lawson David Metz Anil Minocha Joshua Ofman Edward C. Oldfield III David Ott C. S. Pitchumoni K. Rajender Reddy Douglas Rex
Arvey Rogers Richard Sampliner Marvin Schuster Paul Souney Christina Surawicz Nimish Vakil Harlan Vingan F. Taylor Wooton III
Diagnosis of Acute Right Lower Quadrant Pain and Appendicitis by CT Scan: Do We Still Need the Clinician?
performed in nearly all female and many male patients. (Am J Gastroenterol 2000;95:1355–1357. © 2000 by Am. Coll. of Gastroenterology)
Roa PM, Rhea JT, Ratner DW, et al. Effect of Computer Tomography of the Appendix on Treatment of Patients and Use of Hospital Resources: Introduction of Appendiceal CT Impact on Negative Appendectomy and Appendiceal Perforation Rates Ann Surg 1999;299:344 –9
This is the latest in a series of articles advocating the use of appendiceal computed tomography (CT) (1–9). In their previous articles, the authors defined the radiological criteria for confirming or ruling out appendicitis, which had a 98% sensitivity, 98% specificity, 98% positive predictive value, 98% negative predictive value, and 98% overall accuracy for diagnosing or ruling out appendicitis. A concern is that their population had symptoms for 5 or more days, which may have selected a subpopulation that had a perforated appendix, as pain that lasts longer than 36 h often results in perforation (2). In these studies, appendiceal CT scans were interpreted as negative for appendicitis when the appendiceal lumen filled completely with contrast material, air, or both, or if an appendix measured 6 mm or less in maximum diameter. Appendiceal CT scans were interpreted as positive for appendicitis if enlarged (⬎6 mm in outer diameter). Appendicitis was diagnosed in cases of nonvisualization of the appendix only in the presence of specific CT signs of appendicitis. These included: an appendicolith, focal cecal apical thickening, an arrowhead sign, a cecal bar or an enlarged appendix with periappendiceal fat stranding ⫾ adjacent bowel wall thickening or fluid (8), abscess, or phlegmon (2, 9). Overall, the diagnosis of acute appendicitis is incorrectly made in at least 20% of patients (10 –13). This is further confirmed in a cooperative European Community six-hospital study (14), whose documented rates of negative appendectomies was 30% of 1254 patients. This high negative appendectomy rate occurred despite the presence of “classic textbook symptoms of right lower quadrant (RLQ) pain” (e.g., direct tenderness, rebound tenderness, and guarding). In addition to false-negative surgical exploration, missed acute appendicitis is the most frequently successful malprac-
ABSTRACT This retrospective study was performed to evaluate the impact of appendiceal computed tomography (CT) on negative appendectomy and appendiceal perforation rates. The population consisted of 493 consecutive patients who underwent appendectomy between 1992 and 1995. They were compared with 209 consecutive patients who underwent appendectomy in 1997 (59% of whom had appendiceal CT) and 206 patients who underwent appendiceal CT in 1997 without subsequent appendectomy. The authors found that before the availability of appendiceal CT, 98 of 493 patients (20%) who underwent surgery for suspected appendicitis had a normal appendix. Whereas, after CT availability, only 15 of 209 patients (7%) who were taken to surgery for appendectomy had a normal appendix. In addition to this decrease in negative appendectomy rates, the appendiceal perforation rates also dropped significantly from 22% before CT availability to 14% after CT availability. Of 206 patients who underwent appendiceal CT in 1997, 105 (51%) had a normal appendix, and thus avoided appendectomy. CT identified alternate diagnosis in these patients. Subgroup analysis revealed that the greatest change in negative appendectomy rates was in women in whom the rate decreased from 35% before CT availability to 11% after CT availability. In men, negative appendectomy rates decreased from 11% to 5%. In boys, it changed from 10% to 5%. And in girls, from 18% to 12%. The authors advocate that, as a result of this study, appendiceal CT should be
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tice claim against emergency department physicians (15). In a retrospective review of malpractice claims between 1982 and 1989, Rusnak et al. (16) identified differences between correctly diagnosed and misdiagnosed appendicitis that resulted in litigation. Misdiagnosed patients had a 91% incidence of ruptured appendix, more extensive surgical procedures, and postoperative complications. Misdiagnosis in this study was more likely to occur in patients who presented atypically, were not thoroughly examined, as indexed by lack of proper documentation of complete physical examinations, or were given inappropriate IM narcotic pain medications and then discharged from the emergency department, or were diagnosed with gastroenteritis despite the absence of typical diagnostic criteria and without proper lab confirmation (16). It is also important to note that delayed appendiceal surgery after appendiceal perforation increases the risk of postoperative complications to 39% compared with 8% for simple appendicitis (17, 18). Conversely, the appendix is normal in 15– 40% of patients who undergo emergency appendectomy (14 –21). Therefore, any additional test that can make our clinical examinations more accurate would certainly be welcome— but would it be worth the expense? Previously, the authors (7) performed a prospective study on the value of appendiceal CT in 100 consecutive patients referred for observation of suspected appendicitis or for urgent appendectomy. Treatment plans before CT were compared with the patient’s actual treatment. They found that the results of CT led to changes in the treatment of 59 (59%) patients. In addition, it prevented unnecessary appendectomy in 13 patients, saving $47,281, and eliminating 50 days of unnecessary hospital admission, thereby saving an additional $20,250. This resulted in a net saving of $44,731 ($47,281—20,250 less 100 appendiceal CT studies of $22,800). Thus, CT performed in patients who present with suspected appendicitis not only improves patient care, but also reduces the use of hospital resources. They also found that the negative appendectomy rate in pediatric patients in whom diagnosis may be most difficult, dropped from 13% to 7% (p ⫽ 0.224). Similarly, there was a decrease in the pediatric perforation rate from 23% to 15% (p ⬎ 0.05). Unfortunately, the authors do not address whether there may be a subset of patients in whom clinical diagnosis has such a high accuracy that appendiceal CT use would be of little benefit. Therefore, these results may reflect that clinical accuracy was generally higher in the pediatric patients or simply that the small sample size prevented statistical significance from being obtained. It is important to note that in all of these studies patients were referred for CT through the emergency department of the hospital only if appendicitis was the leading clinical suspicion. Thus, CT was a goal-directed test, and not an “add-on” test or just another test to do in nonspecific abdominal pain. Female patients with suspected appendicitis had the most dramatic drop in negative appendectomy rate (from 31% to 11%) after undergoing appendiceal CT. It is not surprising
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that the misdiagnosis rate of RLQ pain is especially increased in women in the childbearing age as gynecological causes can stimulate appendicitis (22, 23) as well as gastroenteritis, and urinary infections found in adults and children (12). Ultrasound has also successfully been used for diagnosing acute appendicitis. Schulte et al. (24), in a study of 285 patients, found that the diagnosis of acute appendicitis with ultrasound achieved a sensitivity of 92% with a specificity of 98%, a positive predicted value of 90%, and a negative projected value of 98% with an overall accuracy of 98%. Ultrasound-differentiated mesenteric lymphadenitis was found in 12%, and terminal ileitis accompanied by mesenteric lymphadenitis was seen in 9%. Galindo et al. (25), in a study of 112 patients who were younger than 14 y, evaluated the effect of the diagnostic value of sonography in those who had appendicitis and found that the appendectomy rate decreased by 7% and the perforation/gangrenous appendicitis rate decreased by 29%. Thus, ultrasonography performed by trained professionals is also a useful diagnostic tool for evaluating children who are suspected of having appendicitis. Another pro ultrasound study (26) summarized 13 studies of 5000 patients, which showed a sensitivity of 85% and specificity of 96% if the sonography exam was performed by an experienced examiner. The problem with RLQ ultrasound lies less on its technology than the fact that it is so operator dependent. Its sensitivity is diminished because when not performed by an experienced examiner, a negative exam is not reliable. What about use of enhanced helical CT for diagnosing appendicitis or other RLQ problems in the average community hospital? Funaki et al. (27) found a sensitivity of 97%, specificity of 94%, accuracy of 95%, positive predicted value of 88%, and negative predicted value of 99% for CT performed for suspected appendicitis. An alternative diagnosis was made for 36 patients (54%). However, an objection to this procedure is that more skilled personnel, technicians, and radiologists must be used and they may not be always available in the average community hospital. Therefore, can less invasive, unenhanced helical CT without oral, rectal, or i.v. contrast material be used? As early as 1993, Malone et al. (28) showed that unenhanced CT was a useful test for diagnosing appendicitis in patients with acute RLQ abdominal pain. Their accuracy was 93%, sensitivity— 87%, specificity—97%, positive predicted value—94%, and negative predicted value—93%. This is not much different than the 1998 Massachusetts General Hospital study (7) in which contrast-enhanced CT was used. Thus noninvasive procedure may be more practical in many more community hospitals that do not have the 24-h coverage of specialized personnel to administer contrast material found in tertiary care institutions. Should CT be the first imaging study in a nongoaldirected strategy in the diagnosis of abdominal pain? Can CT save us from doing the physical examination and lab work traditionally necessary for making an accurate diag-
AJG – May, 2000
nosis? Should every emergency room patient simply undergo routine CT scan before further workup is done in an effort to save time and effort? Benson et al. (29) reviewed the abdominal CT scans of 53 patients who had abdominal pain without objective physical radiographic or laboratory abnormalities. Forty of these 53 patients presented with abdominal pain alone, whereas the remainder had abdominal pain associated with nausea, vomiting, or mild weight loss. Abdominal CT scans in all patients were interpreted as normal. In all but one patient, the final diagnosis was an insignificant benign condition. This would lend proof that the clinician is necessary to suspect patients with appendicitis and CT should be used, but only in a goaldirected fashion as it can improve diagnosis, decrease false negative exploration, and establish other causes of RLQ abdominal pain especially in women of child-bearing age. If time permits, an ultrasound can be done and if negative, it can be followed by a CT as in the study by Zoller et al. (30). This is especially important in children and young women without sufficient fat surrounding the area, which makes the diagnosis less easy to interpret because intraperitoneal fat will show up inflammatory changes much easier. In this particular group of patients, an ultrasound first followed by an unenhanced CT, and then an enhanced CT, is probably the ideal way to make a diagnosis, especially if the patient is capable of pinpointing an area of tenderness in the RLQ or elsewhere in the abdomen. These are clinical judgments that should be made on a case-by-case basis. The clinician is still definitely needed to make these judgments. Perry Hookman, M.D. Jamie S. Barkin, M.D., F.A.C.P., M.A.C.G University of Miami School of Medicine/Mt. Sinai Medical Center Division of Gastroenterology Miami, Florida
REFERENCES 1. Rao PM, Rhea JT, Novelline RA, et al. Prospective evaluation of a helical CT technique for diagnosing appendicitis: The focused appendix CT examination. Radiology 1997;202:139 – 44. 2. Rao PM, Wittenberg J, McDowell RK, et al. The arrowhead sign of appendicitis: A new CT finding pointing to the pathology. Radiology 1997;202:363– 6. 3. Rao PM, Rhea JT, Novelline RA. Helical CT incidence and characterization of appendicitis in 100 patients with appendicitis. Emerg Radiol 1997;2:55– 61. 4. Rao PM, Rhea JT, Novelline RA. CT diagnosis of mesenteric adenitis. Radiology 1997;202:145–9. 5. Rhea JT, Rao PM, Novelline RA, et al. A focused appendiceal CT technique to reduce the cost of caring for patients with clinically suspected appendicitis. AJR 1997;169:113– 8. 6. Rao PM, Rhea JT, Novelline RA, et al. Helical CT scanning with contrast material administered only through the colon for imaging of suspected appendicitis. AJR 1997;169:1275– 80. 7. Rao PM, Rhea JT, Novelline RA, et al. Effect of computed tomography of the appendix on treatment of patients and use of hospital resources. N Engl J Med 1998;338:141– 6.
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8. Rao PM, Rhea JT, Novelline RA. Sensitivity and specificity of the individual CT signs of appendicitis: Experience with 200 helical appendiceal CT examinations. J Comput Assist Tomogr 1997;21:686 –92. 9. Rao PM, Rhea JT, Novelline RA. Distal appendicitis: CT appearance and diagnosis. Radiology 1997;204:709 –12. 10. Reynolds SL. Missed appendicitis in a pediatric emergency department. Pediatr Emerg Care 1993;9:1–3. 11. Rothrock SG, Green SM, Dobson M, et al. Misdiagnosis of appendicitis in nonpregnant women of childbearing age. J Emerg Med 1995;13:1– 8. 12. McCallion J, Canning GP, Knight RV, et al. Acute appendicitis in the elderly: A 5-year retrospective study. Age Ageing 1987;16:256 – 60. 13. Rothrock SG, Skeoch G, Rush JT, et al. Clinical features of misdiagnosed appendicitis in children. Ann Emerg Med 1991; 20:45–50. 14. Bohner H, Yang Q, Franke K, et al. Significance of anamnesis and clinical findings for diagnosis of acute appendicitis. Z Gastroenterol 1994;32:579 – 83. 15. Thautlein JJ, Lambert RL, Miller J. Malpractice in the emergency department—Review of 200 cases. Ann Emerg Med 1984;13:709 –11. 16. Rusnak RA, Borer JM, Fastow JS. Misdiagnosis of acute appendicitis: Common features discovered in cases after litigation. Am J Emerg Med 1994;12:397– 402. 17. Calder JDF, Gajraj H. Recent advances in the diagnosis and treatment of acute appendicitis. Br J Hosp Med 1995;54:129 –33. 18. Velanorich V, Satava R. Balancing the normal appendectomy rate with the perforated appendicitis rate: Implication for quality assurance. Am Surg 1992;58:264 –9. 19. Jess P, Bjerregaard B, Brynitz S, et al. Acute appendicitis: Prospective trial concerning diagnostic accuracy and complications. Am J Surg 1981;141:232– 4. 20. Lewis FR, Holcroft JW, Boey J, et al. Appendicitis: A critical review of diagnosis and treatment in 1,000 cases. Arch Surg 1975;110:677– 84. 21. Izbicki JR, Knoefel WT, Wilker DK, et al. Accurate diagnosis of acute appendicitis: A retrospective and prospective analysis of 686 patients. Eur J Surg 1992;158:227–31. 22. Viahakis-Miliaras E, Miliaras D, Koutsoumis G, et al. Paratubal cysts in young females as an incidental finding in laparotomies performed for right lower quadrant abdominal pain. Pediatr Surg Int 1998;13:141–2. 23. Al Salilli M, Vilos GA. Prospective evaluation of laparoscopic appendectomy in women with chronic right lower quadrant pain. J Am Assoc Gynecol Laparosc 1995;2:139 – 42. 24. Schulte B, Beyer D, Kaiser C, et al. Ultrasonography in suspected acute appendicitis in childhood—Report of 1285 cases. Eur J Ultrasound 1998;8:177– 82. 25. Galindo Gallego M, Calleja Lopez S, Nieto MA, et al. The diagnostic value of echography in appendicitis in children. An Esp Pediatr 1998;48:28 –32. 26. Pohl D, Golub R, Schwartz GE, et al. Appendiceal ultrasonography performed by nonradiologists: Does it help in the diagnostic process? J Ultrasound Med 1998;17:217–21. 27. Funaki B, Grosskreutz SR, Funaki CN. Using un-enhanced helical CT with enteric contrast material for suspected appendicitis in patients treated at a community hospital. Am J Roentgenol 1998;171:997–1001. 28. Malone AJ Jr, Wolf CR, Malmed AS, et al. Diagnosis of acute appendicitis: Value of un-enhanced CT. Am J Roentgenol 1993;160:763– 6. 29. Benson M, Bree RL, Schwab RE, et al. Computed tomographic studies of the painful abdomen. Radiology 1985;155:443– 4. 30. Zoller WG, Kellner H, Schwerk WB. Value of ultrasound in diagnosis of acute appendicitis. Bildegbung 1996;63:78 – 82.
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Therapeutic Face-Off: Band Ligation Versus Beta Blockage for Variceal Bleeding Sarin SK, Lambada GS, Kumar M, et al. Comparison of Endoscopic Ligation and Propranolol for the Primary Prevention of Variceal Bleeding N Engl J Med 1999;340:988 –93
ABSTRACT Sarin et al. prospectively compared propranolol treatment and endoscopic ligation for primary prevention of esophageal variceal bleeding. The patients were randomized to receive either beta-blocker therapy with an aim to decrease heart rate by 25% or weekly variceal ligation until obliteration was achieved. The study population of 89 patients were at high risk for bleeding as determined by the presence of large varices, defined as ⬎5 mm in diameter. Eighty-two of these patients were cirrhotic. Forty-four were treated with propranolol, and 45 underwent variceal ligation. The mean duration of post-treatment follow-up for the medical arm was 14 months compared to 13 months for the endoscopic group. The mean time required to achieve the desired heart rate reduction was approximately 2.5 days, and an average of 3.2 ligation sessions were necessary to achieve variceal obliteration. At 18 months after initiation of treatment, the statistical probability of bleeding was 43% in the propranolol group compared to 15% in the ligation group. Twelve patients in the propranolol group and four in the ligation group exhibited bleeding; however, three of the four in the ligation group bled before complete variceal obliteration. No serious complications occurred in the ligation group, whereas betablocker therapy was discontinued in two patients because of side effects (hypotension, altered mental status). Five deaths occurred in each group; variceal bleeding was the cause in four propranolol and three ligation patients. The authors concluded that endoscopic ligation appears to be a safe and more effective treatment than propranolol for patients with high-risk esophageal varices. (Am J Gastroenterol 2000;95:1358 –1359. © 2000 by Am. Coll. of Gastroenterology)
COMMENT Cirrhotic patients who experience an initial esophageal variceal bleed secondary to large varices incur significant mortality ranging from 30% to 70% (1). For this reason, numerous therapies have been evaluated for primary prophylaxis. Accordingly, nonselective beta-blocker therapy has been recommended as primary prevention for individuals with large esophageal varices. It has been difficult to titrate the dose for maximal treatment efficacy, since this is best determined by measuring the hepatic venous pressure gradient (2). Unfortunately, this invasive technique is not
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readily available. The goal of beta-blocker therapy is to decrease portal venous pressure to 12 mm mercury. This correlates somewhat with decreased heart rate by 25%. Although patients are frequently treated with beta-blockers as primary prevention, studies have demonstrated that the requisite reduction in hepatic vein pressure gradient is rarely achieved (3). Furthermore, associated medication side effects are also frequently limiting factors, especially with the addition of nitrate (4). Rather than decrease portal pressure with the associated secondary effects of medications, endoscopic variceal sclerotherapy has been used to clot off these varices, but it is fraught with a significant complication rate. The development of endoscopic variceal ligation is a possible alternative for primary prevention, in view of its kinder side effect profile. It was compared with medical therapy by Sarin et al. who found that the probability of bleeding was more than double— 43% versus 15% in the propranolol treated groups. In an accompanying editorial, Burroughs and Patch (5) note that the bleeding rate of 43% in the propranolol group was significantly higher than that reported in previous studies, which ranges between 15% and 20%, perhaps because of the lower dose of beta blockers that was employed in this study. In addition, no difference in overall mortality or that caused by bleeding was demonstrated despite a significant reduction in the incidence of bleeding in the ligation group. They suggest that these results be interpreted with caution and recommend that the current practice of instituting nonselective beta blockade be continued as first-line primary prevention of bleeding in these patients. Their editorial also concludes that endoscopic variceal ligation for primary prevention should be reserved for patients who are unsuitable for propranolol, either by presence of contraindications or medication intolerance. Despite caveats enumerated in the editorial, this study offers an attractive alternative to medical treatment to decrease the risk of initial esophageal variceal bleeding in cirrhotics harboring large esophageal varices. Endoscopic variceal ligation has demonstrated an excellent side effect profile and should certainly be considered in patients who are not optimal candidates for beta blockade. These results need to be confirmed in future, large, prospective, randomized, controlled trials. It would also be important to investigate the potential additive effect of medical treatment and endoscopic variceal ligation. Jesse A. Green, M.D. Rafael Amaro, M.D. Jamie S. Barkin, M.D., F.A.C.P., M.A.C.G. University of Miami School of Medicine/Mt. Sinai Medical Center Division of Gastroenterology Miami, Florida Slocum Dickson Medical Group, PC New Hartford, New York
AJG – May, 2000
REFERENCES 1. Smith JL, Graham DY. Variceal hemorrhage: A critical evaluation of survival analysis. Gastroenterology 1982;82:968 – 73. 2. Feu F, Garcia-Pagan JC, Bosch J, et al. Relation between portal pressure response to pharmacotherapy and risk of recurrent variceal hemorrhage in patients with cirrhosis. Lancet 1995;346:1056 –9. 3. Banares R, Garcia-Pagan JC, Piqueras B, et al. Carvedilol, a new non-selective beta-blocker with intrinsic alpha-adrenergic activity, has greater portal hypotensive effect than propranolol in patients with cirrhosis. Hepatology 1997;26(suppl):133A. 4. Silvain C, Chauvin C, Verneau A, et al. Combien de cirrhotique sont-ils susceptibles d’etre traite par le propranolol au decours d’une hemorragie digestive? Gastroenterol Clin Biol 1985;9:670 –3 (in French). 5. Burroughs AK, Patch D. Primary prevention of bleeding from esophageal varices. N Engl J Med 1999;340:1033–5 (editorial).
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staging could not be assigned. Preoperative MR imaging correctly indicated the pathological tumor stage in all 25 patients in whom comparisons were possible; complete agreement between both readers in the assignment of the tumor stage was found. There was also good agreement between the preoperative MR measurements of the depth of extramural tumor penetration and those made on the resected specimens. The authors conclude that preoperative thin-section MR imaging accurately indicates the tumor stage of rectal cancer and depth of extramural tumor infiltration. They also believe that the information is valuable for identifying T3 tumors for preoperative adjuvant therapy in patients who are at high risk of failure of complete excision. (Am J Gastroenterol 2000;95:1359 –1360. © 2000 by Am. Coll. of Gastroenterology)
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Staging Rectal Carcinoma With MR Imaging: Improving Accuracy With Newer Techniques Brown G, Richards CJ, Newcombe RG, et al. Rectal Carcinoma: Thin-Section MR Imaging for Staging in 28 Patients Radiology 1999;211:215–22
ABSTRACT In this investigation, the authors evaluated the accuracy of thin-section magnetic resonance (MR) imaging of rectal carcinoma in the preoperative assessment of the depth of extramural tumor infiltration. A total of 28 consecutive patients (eight women, 20 men; mean age, 62 y) with biopsy-proven rectal carcinoma comprised the study population. Nine tumors were in the upper rectum (10 –15 cm from anal verge); eight in the mid-rectum (5–10 cm from verge); and 11 in the distal rectum (⬍5 cm from verge). All patients had preoperative short-course radiation therapy followed by total mesorectal excision, either by anterior resection or abdominoperitoneal excision. All patients underwent MR imaging with use of a fourelement wrap-around surface coil. No bowel preparation, air insufflation, or antispasmodic agents were used. Standard T1- and T2-weighted images were performed initially to plan T2-weighted, thin-section axial imaging through the rectal tumor. Each of the resected rectal tumors were again examined with MR imaging, and then the extent of tumor spread by histopathological evaluation was determined according to the TNM system. The MR images of both the in vivo carcinomas and the resected specimens were interpreted by two readers independently using strict criteria for T-staging. Histopathological results showed five T2 tumors, 18 T3 tumors, and two T4 tumors; three remaining patients had tumors at the resected margins of the specimens, and T-
The prognosis for patients with rectal carcinoma is related to the stage of disease at the time of diagnosis and the initial treatment used (1, 2). The depth of wall invasion and the presence or absence of lymph node metastases are the major factors influencing prognosis in this disease. Detection of rectal carcinoma before the malignancy has invaded to or through the muscular is propria and before lymph node metastases have occurred offers the best prognosis for the patient and the option of more limited surgery. However, before the emergence of endoluminal ultrasound and magnetic resonance (MR) imaging, assessment of wall invasion by radiological imaging, including computed tomography (CT) examination, was not possible (3, 4). MR imaging combines attributes of both CT and ultrasonography in staging of rectal carcinoma; MR can evaluate the depth of local wall invasion, regional lymph node metastases, and also assess the liver and remainder of the abdomen. Special MR techniques are needed to examine the rectum, including the use of various surface and endorectal coils; also, newer computerized techniques are emerging that help to provide faster acquisition of images and better anatomic resolution. Compared to endorectal ultrasound staging of rectal carcinoma, MR has shown similar results and limitations in both assessing the extent of wall invasion and lymph node involvement (4, 5). In one recent study, endoscopic ultrasound found a 70% accuracy in staging rectal malignancy compared to 80% for MR imaging using an endorectal coil (6). In the present investigation, Brown et al. have shown excellent preoperative prediction of the stage of rectal carcinoma using thin-section MR techniques. Indeed, their results are a substantial improvement over those found in other recent studies using endoluminal ultrasound and MR imaging and warrant further investigations of this modality (4 – 6). Several comments regarding the use of radiation therapy in their patients before surgery and the lack of evaluation of lymph node metastases are needed. All of their
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patients had preoperative radiation, but no discernible histopathological evidence of a radiation effect on the tumors was found; thus, the authors did not consider the treatment to impact on their results. Also, no attempt at lymph node staging by MR imaging was done because of the authors’ reservations about the reliability of imaging modalities for predicting lymph node involvement. Lymph node assessment is certainly important for staging rectal carcinoma and determines specific categories in the Dukes’ classifications and the M staging in the TNM system. However, the accuracy of determining lymph node involvement by imaging has been disappointing, regardless of the technique used (4). In conclusion, thin-section MR imaging of the pelvis for rectal carcinoma staging is a promising innovation that may permit better preoperative assessment of rectal cancer. Further investigations are needed as the MR equipment and methodology improves to assess its role in the management of patients with this disease and to determine if prognosis can be affected. Whether MR imaging might replace endoluminal ultrasound for staging rectal carcinoma is another consideration. Improved MR imaging of the rectum provides a better anatomic depiction of the neoplasm relative to surrounding anatomic structures in the pelvis and, in addi-
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tion, examines the remainder of the abdomen, including the liver. David J. Ott, M.D., F.A.C.G. Department of Radiology Wake Forest University School of Medicine Winston-Salem, North Carolina
REFERENCES 1. Loggie BW. Surgical concepts in the treatment of colorectal cancer. Semin Roentgenol 1996;31:111–7. 2. Skibber JM. Management of colorectal cancer. In: Meyers MA, ed. Neoplasms of the digestive tract. Philadelphia: Lippincott-Raven, 1998:303– 6. 3. Scharling ES, Wolfman NT, Bechtold RE. Computed tomography evaluation of colorectal carcinoma. Semin Roentgenol 1996;31:142–53. 4. Ott DJ, Wolfman NT, Scharling ES, et al. Overview of imaging in colorectal carcinoma. Dig Dis 1998;16:175– 82. 5. Zagoria RJ, Wolfman NT. Magnetic resonance imaging of colorectal cancer. Semin Roentgenol 1996;31:162–5. 6. Zagoria RJ, Schlarb CA, Ott DJ, et al. Assessment of rectal tumor infiltration utilizing endorectal MR imaging and comparison with endoscopic rectal sonography. J Surg Oncol 1997;64:312–7.
Vol. 95, No. 5, 2000 ISSN 0002-9270/00/$20.00 PII S0002-9270(00)00825-X
WORLD LITERATURE REVIEW Editor: David Johnson, M.D., F.A.C.G. REVIEW PANEL Jamie Barkin David Bjorkman Cedric Bremner William Carey Donald J. Clement Harold Conn Jack DiPalma Mark Fendrick M. Brian Fennerty
Mark Flemmer Norman Gitlin Christopher Gostout Robert Hawes Jorge Herrera Brenda Hoffman John Johanson Philip Katz Timothy Koch
Mark Lawson David Metz Anil Minocha Joshua Ofman Edward C. Oldfield III David Ott C. S. Pitchumoni K. Rajender Reddy Douglas Rex
Arvey Rogers Richard Sampliner Marvin Schuster Paul Souney Christina Surawicz Nimish Vakil Harlan Vingan F. Taylor Wooton III
Diagnosis of Acute Right Lower Quadrant Pain and Appendicitis by CT Scan: Do We Still Need the Clinician?
performed in nearly all female and many male patients. (Am J Gastroenterol 2000;95:1355–1357. © 2000 by Am. Coll. of Gastroenterology)
Roa PM, Rhea JT, Ratner DW, et al. Effect of Computer Tomography of the Appendix on Treatment of Patients and Use of Hospital Resources: Introduction of Appendiceal CT Impact on Negative Appendectomy and Appendiceal Perforation Rates Ann Surg 1999;299:344 –9
This is the latest in a series of articles advocating the use of appendiceal computed tomography (CT) (1–9). In their previous articles, the authors defined the radiological criteria for confirming or ruling out appendicitis, which had a 98% sensitivity, 98% specificity, 98% positive predictive value, 98% negative predictive value, and 98% overall accuracy for diagnosing or ruling out appendicitis. A concern is that their population had symptoms for 5 or more days, which may have selected a subpopulation that had a perforated appendix, as pain that lasts longer than 36 h often results in perforation (2). In these studies, appendiceal CT scans were interpreted as negative for appendicitis when the appendiceal lumen filled completely with contrast material, air, or both, or if an appendix measured 6 mm or less in maximum diameter. Appendiceal CT scans were interpreted as positive for appendicitis if enlarged (⬎6 mm in outer diameter). Appendicitis was diagnosed in cases of nonvisualization of the appendix only in the presence of specific CT signs of appendicitis. These included: an appendicolith, focal cecal apical thickening, an arrowhead sign, a cecal bar or an enlarged appendix with periappendiceal fat stranding ⫾ adjacent bowel wall thickening or fluid (8), abscess, or phlegmon (2, 9). Overall, the diagnosis of acute appendicitis is incorrectly made in at least 20% of patients (10 –13). This is further confirmed in a cooperative European Community six-hospital study (14), whose documented rates of negative appendectomies was 30% of 1254 patients. This high negative appendectomy rate occurred despite the presence of “classic textbook symptoms of right lower quadrant (RLQ) pain” (e.g., direct tenderness, rebound tenderness, and guarding). In addition to false-negative surgical exploration, missed acute appendicitis is the most frequently successful malprac-
ABSTRACT This retrospective study was performed to evaluate the impact of appendiceal computed tomography (CT) on negative appendectomy and appendiceal perforation rates. The population consisted of 493 consecutive patients who underwent appendectomy between 1992 and 1995. They were compared with 209 consecutive patients who underwent appendectomy in 1997 (59% of whom had appendiceal CT) and 206 patients who underwent appendiceal CT in 1997 without subsequent appendectomy. The authors found that before the availability of appendiceal CT, 98 of 493 patients (20%) who underwent surgery for suspected appendicitis had a normal appendix. Whereas, after CT availability, only 15 of 209 patients (7%) who were taken to surgery for appendectomy had a normal appendix. In addition to this decrease in negative appendectomy rates, the appendiceal perforation rates also dropped significantly from 22% before CT availability to 14% after CT availability. Of 206 patients who underwent appendiceal CT in 1997, 105 (51%) had a normal appendix, and thus avoided appendectomy. CT identified alternate diagnosis in these patients. Subgroup analysis revealed that the greatest change in negative appendectomy rates was in women in whom the rate decreased from 35% before CT availability to 11% after CT availability. In men, negative appendectomy rates decreased from 11% to 5%. In boys, it changed from 10% to 5%. And in girls, from 18% to 12%. The authors advocate that, as a result of this study, appendiceal CT should be
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tice claim against emergency department physicians (15). In a retrospective review of malpractice claims between 1982 and 1989, Rusnak et al. (16) identified differences between correctly diagnosed and misdiagnosed appendicitis that resulted in litigation. Misdiagnosed patients had a 91% incidence of ruptured appendix, more extensive surgical procedures, and postoperative complications. Misdiagnosis in this study was more likely to occur in patients who presented atypically, were not thoroughly examined, as indexed by lack of proper documentation of complete physical examinations, or were given inappropriate IM narcotic pain medications and then discharged from the emergency department, or were diagnosed with gastroenteritis despite the absence of typical diagnostic criteria and without proper lab confirmation (16). It is also important to note that delayed appendiceal surgery after appendiceal perforation increases the risk of postoperative complications to 39% compared with 8% for simple appendicitis (17, 18). Conversely, the appendix is normal in 15– 40% of patients who undergo emergency appendectomy (14 –21). Therefore, any additional test that can make our clinical examinations more accurate would certainly be welcome— but would it be worth the expense? Previously, the authors (7) performed a prospective study on the value of appendiceal CT in 100 consecutive patients referred for observation of suspected appendicitis or for urgent appendectomy. Treatment plans before CT were compared with the patient’s actual treatment. They found that the results of CT led to changes in the treatment of 59 (59%) patients. In addition, it prevented unnecessary appendectomy in 13 patients, saving $47,281, and eliminating 50 days of unnecessary hospital admission, thereby saving an additional $20,250. This resulted in a net saving of $44,731 ($47,281—20,250 less 100 appendiceal CT studies of $22,800). Thus, CT performed in patients who present with suspected appendicitis not only improves patient care, but also reduces the use of hospital resources. They also found that the negative appendectomy rate in pediatric patients in whom diagnosis may be most difficult, dropped from 13% to 7% (p ⫽ 0.224). Similarly, there was a decrease in the pediatric perforation rate from 23% to 15% (p ⬎ 0.05). Unfortunately, the authors do not address whether there may be a subset of patients in whom clinical diagnosis has such a high accuracy that appendiceal CT use would be of little benefit. Therefore, these results may reflect that clinical accuracy was generally higher in the pediatric patients or simply that the small sample size prevented statistical significance from being obtained. It is important to note that in all of these studies patients were referred for CT through the emergency department of the hospital only if appendicitis was the leading clinical suspicion. Thus, CT was a goal-directed test, and not an “add-on” test or just another test to do in nonspecific abdominal pain. Female patients with suspected appendicitis had the most dramatic drop in negative appendectomy rate (from 31% to 11%) after undergoing appendiceal CT. It is not surprising
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that the misdiagnosis rate of RLQ pain is especially increased in women in the childbearing age as gynecological causes can stimulate appendicitis (22, 23) as well as gastroenteritis, and urinary infections found in adults and children (12). Ultrasound has also successfully been used for diagnosing acute appendicitis. Schulte et al. (24), in a study of 285 patients, found that the diagnosis of acute appendicitis with ultrasound achieved a sensitivity of 92% with a specificity of 98%, a positive predicted value of 90%, and a negative projected value of 98% with an overall accuracy of 98%. Ultrasound-differentiated mesenteric lymphadenitis was found in 12%, and terminal ileitis accompanied by mesenteric lymphadenitis was seen in 9%. Galindo et al. (25), in a study of 112 patients who were younger than 14 y, evaluated the effect of the diagnostic value of sonography in those who had appendicitis and found that the appendectomy rate decreased by 7% and the perforation/gangrenous appendicitis rate decreased by 29%. Thus, ultrasonography performed by trained professionals is also a useful diagnostic tool for evaluating children who are suspected of having appendicitis. Another pro ultrasound study (26) summarized 13 studies of 5000 patients, which showed a sensitivity of 85% and specificity of 96% if the sonography exam was performed by an experienced examiner. The problem with RLQ ultrasound lies less on its technology than the fact that it is so operator dependent. Its sensitivity is diminished because when not performed by an experienced examiner, a negative exam is not reliable. What about use of enhanced helical CT for diagnosing appendicitis or other RLQ problems in the average community hospital? Funaki et al. (27) found a sensitivity of 97%, specificity of 94%, accuracy of 95%, positive predicted value of 88%, and negative predicted value of 99% for CT performed for suspected appendicitis. An alternative diagnosis was made for 36 patients (54%). However, an objection to this procedure is that more skilled personnel, technicians, and radiologists must be used and they may not be always available in the average community hospital. Therefore, can less invasive, unenhanced helical CT without oral, rectal, or i.v. contrast material be used? As early as 1993, Malone et al. (28) showed that unenhanced CT was a useful test for diagnosing appendicitis in patients with acute RLQ abdominal pain. Their accuracy was 93%, sensitivity— 87%, specificity—97%, positive predicted value—94%, and negative predicted value—93%. This is not much different than the 1998 Massachusetts General Hospital study (7) in which contrast-enhanced CT was used. Thus noninvasive procedure may be more practical in many more community hospitals that do not have the 24-h coverage of specialized personnel to administer contrast material found in tertiary care institutions. Should CT be the first imaging study in a nongoaldirected strategy in the diagnosis of abdominal pain? Can CT save us from doing the physical examination and lab work traditionally necessary for making an accurate diag-
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nosis? Should every emergency room patient simply undergo routine CT scan before further workup is done in an effort to save time and effort? Benson et al. (29) reviewed the abdominal CT scans of 53 patients who had abdominal pain without objective physical radiographic or laboratory abnormalities. Forty of these 53 patients presented with abdominal pain alone, whereas the remainder had abdominal pain associated with nausea, vomiting, or mild weight loss. Abdominal CT scans in all patients were interpreted as normal. In all but one patient, the final diagnosis was an insignificant benign condition. This would lend proof that the clinician is necessary to suspect patients with appendicitis and CT should be used, but only in a goaldirected fashion as it can improve diagnosis, decrease false negative exploration, and establish other causes of RLQ abdominal pain especially in women of child-bearing age. If time permits, an ultrasound can be done and if negative, it can be followed by a CT as in the study by Zoller et al. (30). This is especially important in children and young women without sufficient fat surrounding the area, which makes the diagnosis less easy to interpret because intraperitoneal fat will show up inflammatory changes much easier. In this particular group of patients, an ultrasound first followed by an unenhanced CT, and then an enhanced CT, is probably the ideal way to make a diagnosis, especially if the patient is capable of pinpointing an area of tenderness in the RLQ or elsewhere in the abdomen. These are clinical judgments that should be made on a case-by-case basis. The clinician is still definitely needed to make these judgments. Perry Hookman, M.D. Jamie S. Barkin, M.D., F.A.C.P., M.A.C.G University of Miami School of Medicine/Mt. Sinai Medical Center Division of Gastroenterology Miami, Florida
REFERENCES 1. Rao PM, Rhea JT, Novelline RA, et al. Prospective evaluation of a helical CT technique for diagnosing appendicitis: The focused appendix CT examination. Radiology 1997;202:139 – 44. 2. Rao PM, Wittenberg J, McDowell RK, et al. The arrowhead sign of appendicitis: A new CT finding pointing to the pathology. Radiology 1997;202:363– 6. 3. Rao PM, Rhea JT, Novelline RA. Helical CT incidence and characterization of appendicitis in 100 patients with appendicitis. Emerg Radiol 1997;2:55– 61. 4. Rao PM, Rhea JT, Novelline RA. CT diagnosis of mesenteric adenitis. Radiology 1997;202:145–9. 5. Rhea JT, Rao PM, Novelline RA, et al. A focused appendiceal CT technique to reduce the cost of caring for patients with clinically suspected appendicitis. AJR 1997;169:113– 8. 6. Rao PM, Rhea JT, Novelline RA, et al. Helical CT scanning with contrast material administered only through the colon for imaging of suspected appendicitis. AJR 1997;169:1275– 80. 7. Rao PM, Rhea JT, Novelline RA, et al. Effect of computed tomography of the appendix on treatment of patients and use of hospital resources. N Engl J Med 1998;338:141– 6.
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8. Rao PM, Rhea JT, Novelline RA. Sensitivity and specificity of the individual CT signs of appendicitis: Experience with 200 helical appendiceal CT examinations. J Comput Assist Tomogr 1997;21:686 –92. 9. Rao PM, Rhea JT, Novelline RA. Distal appendicitis: CT appearance and diagnosis. Radiology 1997;204:709 –12. 10. Reynolds SL. Missed appendicitis in a pediatric emergency department. Pediatr Emerg Care 1993;9:1–3. 11. Rothrock SG, Green SM, Dobson M, et al. Misdiagnosis of appendicitis in nonpregnant women of childbearing age. J Emerg Med 1995;13:1– 8. 12. McCallion J, Canning GP, Knight RV, et al. Acute appendicitis in the elderly: A 5-year retrospective study. Age Ageing 1987;16:256 – 60. 13. Rothrock SG, Skeoch G, Rush JT, et al. Clinical features of misdiagnosed appendicitis in children. Ann Emerg Med 1991; 20:45–50. 14. Bohner H, Yang Q, Franke K, et al. Significance of anamnesis and clinical findings for diagnosis of acute appendicitis. Z Gastroenterol 1994;32:579 – 83. 15. Thautlein JJ, Lambert RL, Miller J. Malpractice in the emergency department—Review of 200 cases. Ann Emerg Med 1984;13:709 –11. 16. Rusnak RA, Borer JM, Fastow JS. Misdiagnosis of acute appendicitis: Common features discovered in cases after litigation. Am J Emerg Med 1994;12:397– 402. 17. Calder JDF, Gajraj H. Recent advances in the diagnosis and treatment of acute appendicitis. Br J Hosp Med 1995;54:129 –33. 18. Velanorich V, Satava R. Balancing the normal appendectomy rate with the perforated appendicitis rate: Implication for quality assurance. Am Surg 1992;58:264 –9. 19. Jess P, Bjerregaard B, Brynitz S, et al. Acute appendicitis: Prospective trial concerning diagnostic accuracy and complications. Am J Surg 1981;141:232– 4. 20. Lewis FR, Holcroft JW, Boey J, et al. Appendicitis: A critical review of diagnosis and treatment in 1,000 cases. Arch Surg 1975;110:677– 84. 21. Izbicki JR, Knoefel WT, Wilker DK, et al. Accurate diagnosis of acute appendicitis: A retrospective and prospective analysis of 686 patients. Eur J Surg 1992;158:227–31. 22. Viahakis-Miliaras E, Miliaras D, Koutsoumis G, et al. Paratubal cysts in young females as an incidental finding in laparotomies performed for right lower quadrant abdominal pain. Pediatr Surg Int 1998;13:141–2. 23. Al Salilli M, Vilos GA. Prospective evaluation of laparoscopic appendectomy in women with chronic right lower quadrant pain. J Am Assoc Gynecol Laparosc 1995;2:139 – 42. 24. Schulte B, Beyer D, Kaiser C, et al. Ultrasonography in suspected acute appendicitis in childhood—Report of 1285 cases. Eur J Ultrasound 1998;8:177– 82. 25. Galindo Gallego M, Calleja Lopez S, Nieto MA, et al. The diagnostic value of echography in appendicitis in children. An Esp Pediatr 1998;48:28 –32. 26. Pohl D, Golub R, Schwartz GE, et al. Appendiceal ultrasonography performed by nonradiologists: Does it help in the diagnostic process? J Ultrasound Med 1998;17:217–21. 27. Funaki B, Grosskreutz SR, Funaki CN. Using un-enhanced helical CT with enteric contrast material for suspected appendicitis in patients treated at a community hospital. Am J Roentgenol 1998;171:997–1001. 28. Malone AJ Jr, Wolf CR, Malmed AS, et al. Diagnosis of acute appendicitis: Value of un-enhanced CT. Am J Roentgenol 1993;160:763– 6. 29. Benson M, Bree RL, Schwab RE, et al. Computed tomographic studies of the painful abdomen. Radiology 1985;155:443– 4. 30. Zoller WG, Kellner H, Schwerk WB. Value of ultrasound in diagnosis of acute appendicitis. Bildegbung 1996;63:78 – 82.
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Therapeutic Face-Off: Band Ligation Versus Beta Blockage for Variceal Bleeding Sarin SK, Lambada GS, Kumar M, et al. Comparison of Endoscopic Ligation and Propranolol for the Primary Prevention of Variceal Bleeding N Engl J Med 1999;340:988 –93
ABSTRACT Sarin et al. prospectively compared propranolol treatment and endoscopic ligation for primary prevention of esophageal variceal bleeding. The patients were randomized to receive either beta-blocker therapy with an aim to decrease heart rate by 25% or weekly variceal ligation until obliteration was achieved. The study population of 89 patients were at high risk for bleeding as determined by the presence of large varices, defined as ⬎5 mm in diameter. Eighty-two of these patients were cirrhotic. Forty-four were treated with propranolol, and 45 underwent variceal ligation. The mean duration of post-treatment follow-up for the medical arm was 14 months compared to 13 months for the endoscopic group. The mean time required to achieve the desired heart rate reduction was approximately 2.5 days, and an average of 3.2 ligation sessions were necessary to achieve variceal obliteration. At 18 months after initiation of treatment, the statistical probability of bleeding was 43% in the propranolol group compared to 15% in the ligation group. Twelve patients in the propranolol group and four in the ligation group exhibited bleeding; however, three of the four in the ligation group bled before complete variceal obliteration. No serious complications occurred in the ligation group, whereas betablocker therapy was discontinued in two patients because of side effects (hypotension, altered mental status). Five deaths occurred in each group; variceal bleeding was the cause in four propranolol and three ligation patients. The authors concluded that endoscopic ligation appears to be a safe and more effective treatment than propranolol for patients with high-risk esophageal varices. (Am J Gastroenterol 2000;95:1358 –1359. © 2000 by Am. Coll. of Gastroenterology)
COMMENT Cirrhotic patients who experience an initial esophageal variceal bleed secondary to large varices incur significant mortality ranging from 30% to 70% (1). For this reason, numerous therapies have been evaluated for primary prophylaxis. Accordingly, nonselective beta-blocker therapy has been recommended as primary prevention for individuals with large esophageal varices. It has been difficult to titrate the dose for maximal treatment efficacy, since this is best determined by measuring the hepatic venous pressure gradient (2). Unfortunately, this invasive technique is not
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readily available. The goal of beta-blocker therapy is to decrease portal venous pressure to 12 mm mercury. This correlates somewhat with decreased heart rate by 25%. Although patients are frequently treated with beta-blockers as primary prevention, studies have demonstrated that the requisite reduction in hepatic vein pressure gradient is rarely achieved (3). Furthermore, associated medication side effects are also frequently limiting factors, especially with the addition of nitrate (4). Rather than decrease portal pressure with the associated secondary effects of medications, endoscopic variceal sclerotherapy has been used to clot off these varices, but it is fraught with a significant complication rate. The development of endoscopic variceal ligation is a possible alternative for primary prevention, in view of its kinder side effect profile. It was compared with medical therapy by Sarin et al. who found that the probability of bleeding was more than double— 43% versus 15% in the propranolol treated groups. In an accompanying editorial, Burroughs and Patch (5) note that the bleeding rate of 43% in the propranolol group was significantly higher than that reported in previous studies, which ranges between 15% and 20%, perhaps because of the lower dose of beta blockers that was employed in this study. In addition, no difference in overall mortality or that caused by bleeding was demonstrated despite a significant reduction in the incidence of bleeding in the ligation group. They suggest that these results be interpreted with caution and recommend that the current practice of instituting nonselective beta blockade be continued as first-line primary prevention of bleeding in these patients. Their editorial also concludes that endoscopic variceal ligation for primary prevention should be reserved for patients who are unsuitable for propranolol, either by presence of contraindications or medication intolerance. Despite caveats enumerated in the editorial, this study offers an attractive alternative to medical treatment to decrease the risk of initial esophageal variceal bleeding in cirrhotics harboring large esophageal varices. Endoscopic variceal ligation has demonstrated an excellent side effect profile and should certainly be considered in patients who are not optimal candidates for beta blockade. These results need to be confirmed in future, large, prospective, randomized, controlled trials. It would also be important to investigate the potential additive effect of medical treatment and endoscopic variceal ligation. Jesse A. Green, M.D. Rafael Amaro, M.D. Jamie S. Barkin, M.D., F.A.C.P., M.A.C.G. University of Miami School of Medicine/Mt. Sinai Medical Center Division of Gastroenterology Miami, Florida Slocum Dickson Medical Group, PC New Hartford, New York
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REFERENCES 1. Smith JL, Graham DY. Variceal hemorrhage: A critical evaluation of survival analysis. Gastroenterology 1982;82:968 – 73. 2. Feu F, Garcia-Pagan JC, Bosch J, et al. Relation between portal pressure response to pharmacotherapy and risk of recurrent variceal hemorrhage in patients with cirrhosis. Lancet 1995;346:1056 –9. 3. Banares R, Garcia-Pagan JC, Piqueras B, et al. Carvedilol, a new non-selective beta-blocker with intrinsic alpha-adrenergic activity, has greater portal hypotensive effect than propranolol in patients with cirrhosis. Hepatology 1997;26(suppl):133A. 4. Silvain C, Chauvin C, Verneau A, et al. Combien de cirrhotique sont-ils susceptibles d’etre traite par le propranolol au decours d’une hemorragie digestive? Gastroenterol Clin Biol 1985;9:670 –3 (in French). 5. Burroughs AK, Patch D. Primary prevention of bleeding from esophageal varices. N Engl J Med 1999;340:1033–5 (editorial).
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staging could not be assigned. Preoperative MR imaging correctly indicated the pathological tumor stage in all 25 patients in whom comparisons were possible; complete agreement between both readers in the assignment of the tumor stage was found. There was also good agreement between the preoperative MR measurements of the depth of extramural tumor penetration and those made on the resected specimens. The authors conclude that preoperative thin-section MR imaging accurately indicates the tumor stage of rectal cancer and depth of extramural tumor infiltration. They also believe that the information is valuable for identifying T3 tumors for preoperative adjuvant therapy in patients who are at high risk of failure of complete excision. (Am J Gastroenterol 2000;95:1359 –1360. © 2000 by Am. Coll. of Gastroenterology)
COMMENT
Staging Rectal Carcinoma With MR Imaging: Improving Accuracy With Newer Techniques Brown G, Richards CJ, Newcombe RG, et al. Rectal Carcinoma: Thin-Section MR Imaging for Staging in 28 Patients Radiology 1999;211:215–22
ABSTRACT In this investigation, the authors evaluated the accuracy of thin-section magnetic resonance (MR) imaging of rectal carcinoma in the preoperative assessment of the depth of extramural tumor infiltration. A total of 28 consecutive patients (eight women, 20 men; mean age, 62 y) with biopsy-proven rectal carcinoma comprised the study population. Nine tumors were in the upper rectum (10 –15 cm from anal verge); eight in the mid-rectum (5–10 cm from verge); and 11 in the distal rectum (⬍5 cm from verge). All patients had preoperative short-course radiation therapy followed by total mesorectal excision, either by anterior resection or abdominoperitoneal excision. All patients underwent MR imaging with use of a fourelement wrap-around surface coil. No bowel preparation, air insufflation, or antispasmodic agents were used. Standard T1- and T2-weighted images were performed initially to plan T2-weighted, thin-section axial imaging through the rectal tumor. Each of the resected rectal tumors were again examined with MR imaging, and then the extent of tumor spread by histopathological evaluation was determined according to the TNM system. The MR images of both the in vivo carcinomas and the resected specimens were interpreted by two readers independently using strict criteria for T-staging. Histopathological results showed five T2 tumors, 18 T3 tumors, and two T4 tumors; three remaining patients had tumors at the resected margins of the specimens, and T-
The prognosis for patients with rectal carcinoma is related to the stage of disease at the time of diagnosis and the initial treatment used (1, 2). The depth of wall invasion and the presence or absence of lymph node metastases are the major factors influencing prognosis in this disease. Detection of rectal carcinoma before the malignancy has invaded to or through the muscular is propria and before lymph node metastases have occurred offers the best prognosis for the patient and the option of more limited surgery. However, before the emergence of endoluminal ultrasound and magnetic resonance (MR) imaging, assessment of wall invasion by radiological imaging, including computed tomography (CT) examination, was not possible (3, 4). MR imaging combines attributes of both CT and ultrasonography in staging of rectal carcinoma; MR can evaluate the depth of local wall invasion, regional lymph node metastases, and also assess the liver and remainder of the abdomen. Special MR techniques are needed to examine the rectum, including the use of various surface and endorectal coils; also, newer computerized techniques are emerging that help to provide faster acquisition of images and better anatomic resolution. Compared to endorectal ultrasound staging of rectal carcinoma, MR has shown similar results and limitations in both assessing the extent of wall invasion and lymph node involvement (4, 5). In one recent study, endoscopic ultrasound found a 70% accuracy in staging rectal malignancy compared to 80% for MR imaging using an endorectal coil (6). In the present investigation, Brown et al. have shown excellent preoperative prediction of the stage of rectal carcinoma using thin-section MR techniques. Indeed, their results are a substantial improvement over those found in other recent studies using endoluminal ultrasound and MR imaging and warrant further investigations of this modality (4 – 6). Several comments regarding the use of radiation therapy in their patients before surgery and the lack of evaluation of lymph node metastases are needed. All of their
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patients had preoperative radiation, but no discernible histopathological evidence of a radiation effect on the tumors was found; thus, the authors did not consider the treatment to impact on their results. Also, no attempt at lymph node staging by MR imaging was done because of the authors’ reservations about the reliability of imaging modalities for predicting lymph node involvement. Lymph node assessment is certainly important for staging rectal carcinoma and determines specific categories in the Dukes’ classifications and the M staging in the TNM system. However, the accuracy of determining lymph node involvement by imaging has been disappointing, regardless of the technique used (4). In conclusion, thin-section MR imaging of the pelvis for rectal carcinoma staging is a promising innovation that may permit better preoperative assessment of rectal cancer. Further investigations are needed as the MR equipment and methodology improves to assess its role in the management of patients with this disease and to determine if prognosis can be affected. Whether MR imaging might replace endoluminal ultrasound for staging rectal carcinoma is another consideration. Improved MR imaging of the rectum provides a better anatomic depiction of the neoplasm relative to surrounding anatomic structures in the pelvis and, in addi-
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tion, examines the remainder of the abdomen, including the liver. David J. Ott, M.D., F.A.C.G. Department of Radiology Wake Forest University School of Medicine Winston-Salem, North Carolina
REFERENCES 1. Loggie BW. Surgical concepts in the treatment of colorectal cancer. Semin Roentgenol 1996;31:111–7. 2. Skibber JM. Management of colorectal cancer. In: Meyers MA, ed. Neoplasms of the digestive tract. Philadelphia: Lippincott-Raven, 1998:303– 6. 3. Scharling ES, Wolfman NT, Bechtold RE. Computed tomography evaluation of colorectal carcinoma. Semin Roentgenol 1996;31:142–53. 4. Ott DJ, Wolfman NT, Scharling ES, et al. Overview of imaging in colorectal carcinoma. Dig Dis 1998;16:175– 82. 5. Zagoria RJ, Wolfman NT. Magnetic resonance imaging of colorectal cancer. Semin Roentgenol 1996;31:162–5. 6. Zagoria RJ, Schlarb CA, Ott DJ, et al. Assessment of rectal tumor infiltration utilizing endorectal MR imaging and comparison with endoscopic rectal sonography. J Surg Oncol 1997;64:312–7.