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A surgeon's view of hepatobiliary scintigraphy
A Surgeon's View of Hepatobiliary Scintigraphy Marvin L. Gliedman and Peter J. Wilk
Hepatobiliary scintigraphy with analogs of iminodiacetic acid (JDA) has become a valuable diagnostic tool for t h e surgeon. It has clearly become the procedure of choice in suspected acute cholecystitis and several postoperative problems, such as the evaluation of biliary-enteric bypasses and leaks. It
URGEONS, including the authors, have
S generally been less than enthusiastic about the role of nuclear imaging in clinical situations.
This has been because (1) several nuclear imaging procedures have a limited diagnostic accuracy (e.g., colloid liver and pancreatic scans), (2) the scans generated often suffer from a lack of specificity (e.g., identification of a "hot" area on a gallium scan), and (3) the examinations have not been readily available and often had to be scheduled as special procedures. Despite these prior prejudices, our experiences with iminodiacetic acid (IDA) imaging of the biliary tract is, happily, changing our attitude. During the past 4 yr, more than 2000 studies have been performed on patients with suspected biliary tract disease here at Montefiore Hospital and Medical Center. The Division of Nuclear Medicine now provides IDA imaging on a 24-hr, 7-day/wk basis. The images obtained usually can be interpreted by even the most naive surgeon with only a minimal background experience. The anatomy is readily identifiable and quite precise and compares favorably with that observed in contrast media cholangiography. While the primary use of IDA imaging has been in the diagnosis of acute cholecystitis, its realized and potential versatility is limited only by the imagination of the surgeon. We have also successfully used IDA imaging for evaluation of patients with jaundice, ampullary stenosis, duodenal diverticula, biliary-enteric anastomoses, and biliary leaks. In addition, nonbiliary pathol-
From the Department of Surgery, Albert Einstein College of Medicine and the Montefiore Hospital and Medical Center, Bronx, N.Y. Reprint requests should be addressed to Marvin L. Gliedman, M.D., Department of Surgery, Albert Einstein College of Medicine, Bronx, N.g. 10467. 9 1982 by Grune & Stratton, Inc. 0001- 2998/8 2/1201~00 2501.00/0
2
has also added very useful information in patients w i t h jaundice, ampullary stenosis, o b s t r u c t i n g duodenal diverticula, and certain nonbiliary problems
where pain patterns might mimic acute cholecystitis. Its availability on a 7-day, 24-hr/day basis enhances its value as well.
ogy has often been diagnosed on the hepatic, renal, or intestinal phases of the studies. ACUTE CHOLECYSTITIS
The common denominator to the development of acute cholecystitis is cystic duct obstruction. IDA imaging in the acutely ill patient has proven uniquely able to rapidly diagnose or exclude the presence of cystic duct obstruction. In a study previously published from our institution, the overall accuracy of diagnosis in 323 patients with acute cholecystitis was 97.6%. The false positive rate was 0.6% and false negative rate 4.8%) The majority of patients presenting with acute right upper quadrant pain are both very elderly and very ill. Rapid diagnosis and treatment is essential in these patients. However, fully onethird of patients, who subsequently are found to have acute cholecystitis, present with only vague or mild symptoms and signs. The abdominal examination may be nonspecific. The patient's temperature, white count, and liver function test may all be normal. 2 Modalities other than IDA imaging have been unsuccessful in more than 50% of patients in detecting pathognemonic signs of acute cholecystitis (such as a distended gallbladder with stones, or air on the wall of the gallbladder). As indicated above, failure to visualize the gallbladder within 4 hr on IDA imaging in a patient with normal biliary to bowel flow has been 98% accurate in the diagnosis of acute cholecystitis) Equally important is that visualization of the gallbladder in this same patient population has allowed us to rapidly eliminate biliary tract disease from the differential diagnosis and to move expeditiously to the identification of the proper diagnosis. The most difficult biliary tract disease to diagnose is acute acalculous cholecystitis. IDA scanning is unmatched in diagnosing this condiSeminars in Nuclear Medicine, Vol. XII, No. 1 (January), 1982
HEPATOBILIARY SCINTIGRAPHY
tion. In 14 of our 15 patients, the diagnosis was promptly established by nonvisualization of the gallbladder or nonvisualization of both the gallbladder and the common bile duct. The 15th patient visualized the gallbladder, but had no response to intravenous sincalide stimulation. The ability of IDA to correctly diagnose acute acalculous cholecystitis is additionally important because these patients are commonly in the period after unrelated surgery or posttrauma and have considerable bowel distention that often obscures ultrasound visualization of the gallbladder. ACUTE COMMON BILE DUCT OBSTRUCTION
IDA imaging has enabled us to diagnose acute common bile duct (CBD) obstruction prior to the development of jaundice or deteriorating liver function. The diagnosis can now be made prior to dilatation of the common bile duct or intrahepatic radicles and before the anatomic diagnosis of ductal dilatation can be made by ultrasound, percutaneous transhepatic cholangiography (PTC) or endoscopic retrograde cholangiopancreatography (ERCP). 3 Our early studies were all done using dimethyl IDA (HIDA). However HIDA does not visualize the biliary tract well when the bilirubin level excedes 5 mg/dl. In our experience, di-isopropyl IDA (DISIDA) allows visualization of the biliary tract up to a level of 30 mg/dl, and we now favor DISIDA for all studies. Of 323 patients who presented with acute right upper quadrant (RUQ) pain here at Montefiore Hospital and Medical Center, 27 had an IDA pattern consistent with acute CBD obstruction (i.e., good hepatic uptake with no discernable movement of the radiotracer to the intestine over a 4-hr or longer time period). In patients who had both IDA imaging and ultrasonography (within several hours of each other), ultrasonography correctly detected a dilated CBD in only 20%. Seventy percent had a normal sized CBD, and in 10% the CBD could not be detected because of dilated bowel.~ CHRONIC CHOLECYSTITIS
We have not found IDA imaging to be useful in the diagnosis of the patient with symptoms of chronic cholecystitis. While delayed visualization of the gallbladder and delayed biliary to
3
bowel transit time have been reliable indicators of chronic cholecystitis, ultrasonographic detection of stones or oral cholecystography remain our prime means of diagnosis of chronic cholecystitis. The presence of these scintigraphic findings in the acute clinical setting has helped to direct the diagnostic work up to the appropriate area. As a general rule, the routine oral cholecystogram has become reserved for the nonemergent outpatient with symptoms suggestive of gallbladder disease and is now rarely performed as an in-hospital study. The intravenous cholangiogram has virtually disappeared at our institution in the evaluation of patients with suspected biliary tract disease. JAUNDICED PATIENT
In the jaundiced patient our standard approach to identification of the point of obstruction and the cause of the obstruction remains the use of ultrasonography followed by PTC and/or ERCP. IDA scanning, however, has been useful in moderately icteric patients who do not show dilated ducts and the question of mechanical versus parenchymal disease is entertained. Because DISIDA allows visualization of the biliary tract to all levels of jaundice, it has regularly permitted the elimination of the medically jaundiced patient from consideration for surgery by showing patent biliary to bowel flow. The scan is safe, simple and noninvasive and obviates the need for PTC or ERCP in a patient with a nondilated biliary system. Although the IDA scan accurately diagnoses biliary tract obstruction, one of its limitations is its resolution, which is not descrete enough to allow an absolute differential diagnosis of stones, tumor, or lymph nodes as a cause for the obstruction. We still rely on the more anatomically specific imaging techniques to make this distinction, e.g., PTC or ERCP. Nor can information about the absolute sizes of the ductal system or the rates of excretion be accurately obtained. Hopefully, ongoing investigations with computer technology will achieve useful results in these areas. Because of its availability 24 hr/day in our institution, IDA scanning has commonly been used as the first test prior to antibiotic therapy in
4
GLIEDMAN AND WILK
presumed cholangitis and then followed, when the appropriate personnel were available, by PTC and/or ERCP prior to surgery. POSTOPERATIVE IDA SCANNING
Prior to IDA scanning, we used the upper gastrointestinal series (UGI), when feasible, to demonstrate patency of biliary-enteric anastomoses. Now, however, IDA scanning has almost replaced the UGI series for this purpose and allows an appreciation of function as well as definition of an intact anastomosis. In patients with biliary-enteric anastomoses that are remote from the duodenum and out of reach of the endoscope, IDA scanning is the only test that can demonstrate patency or occlusion of the biliary-enteric anastomosis. This is particularly applicable to the patient who is postpancreatieoduodenectomy (Whipple resection) or hepatico-jejunostomy (Rodney Smith procedure). In these patients, when.the bilirubin does not promptly fall, the IDA scan allows differentiation between continuing liver failure and an obstructed biliary-enteric anastomosis. IDA scanning has been valuable in patients with selerosing cholangitis. In one of our patients who was 2 yr postbiliary-enteric anastomosis (hepaticojejunostomy), progression of his jaundice meant that either the anastomosis was strictured or his liver parenchymal disease was progressing. Severe hepatic parenchymal disease can prevent ductal dilatation, making PTC difficult while the Roux-en-Y anastomosis generally precludes ERCP. IDA scanning showed prompt emptying into the intestine thereby identifying progression of his intrahepatic sclerosis. We have encountered leaks in a small group of patients following biliary-enteric anastomoses. Our observations indicate that IDA scanning not only identifies the leak but prognosticates the need for reoperation. Our experience to date has shown that those patients who showed some leak, but still had GI continuity and preferential
flow to the intestine, can be expected to close spontaneously. Those patients who have no GI continuity (total leak) or whose preferential flow is to a subhepatic pocket or drain site, warrant reoperation for either a new anastomosis or better drainage. IDA scanning has made the diagnosis of functional ampullary stenosis much easier and reliable. Previously, the diagnosis of ampullary stenosis was made by time-density studies using the IVC. That is, on serial cholangiograms, the CBD visualized progressively to 2-4 hr as compared to a normal peak time of 1 hr associated with rapid disappearance. Delay in excretion of IDA has proven more reliable, safer, and simpler. In a small group of patients with ampullary or periampullary duodenal diverticula, the diverticulum fills and mechanically obstructs the CBD, resulting in repeated episodes of cholangitis. IDA scanning has successfully demonstrated the sustained distention and stasis in the diverticulum by showing filling of the ampullary diverticulum with delayed CBD emptying and delayed emptying of the diverticulum. These patients have been relieved of their symptoms by choledochoduodenostomy. Finally, nonbiliary pathology has been identified. In about 10% of patients studied for acute RUQ pain, the IDA scan has eliminated the biliary tract as the source of the symptoms by visualizing the gallbladder and directing us to unsuspected nonbiliary sources of the patient's symptoms. These chance findings have included hepatomas, metastases, and hepatic abscesses in the hepatocyte phase; absence of a kidney or obstructive uropathy in the renal phase; and intraabdominal abscesses, pancreatic masses, and intestinal obstruction in the intestinal phase. 4 In summary, IDA scanning has rapidly become our most valuable diagnostic tool in the evaluation of patients with suspected biliary tract disease. It has also allowed physiologic evaluations, heretofore not available without direct interventional measurements.
REFERENCES
1. WeissmannHS, Badia J, Sugarman LA, et al: Spectrum of 9~Tc-IDAcholescintigraphypatternsin acute cholecystitis.Radiology138:167-175, 1981 2. SzlabickRE, Catlo JA, Fink-BennettD, et al: Hepatobiliary scanning in the diagnosisof acute colecystitis.Arch Surg 115:540-544, 1980
3. Weissmann HS, Sugarman LA, Freeman LM: The clinical role of technetium-99miminodiaceticacid cholescintigraphy. Nucl Med Annu 35-80, 1981 4. Weissmann HS, Sugarman LA, Frank MS, et al: Serendipity in technetium-99mdimethyliminodiaceticacid eholescintigraphy.Radiology135:449-454, 1980
Hepatobiliary scintigraphy with analogs of iminodiacetic acid (JDA) has become a valuable diagnostic tool for t h e surgeon. It has clearly become the procedure of choice in suspected acute cholecystitis and several postoperative problems, such as the evaluation of biliary-enteric bypasses and leaks. It
URGEONS, including the authors, have
S generally been less than enthusiastic about the role of nuclear imaging in clinical situations.
This has been because (1) several nuclear imaging procedures have a limited diagnostic accuracy (e.g., colloid liver and pancreatic scans), (2) the scans generated often suffer from a lack of specificity (e.g., identification of a "hot" area on a gallium scan), and (3) the examinations have not been readily available and often had to be scheduled as special procedures. Despite these prior prejudices, our experiences with iminodiacetic acid (IDA) imaging of the biliary tract is, happily, changing our attitude. During the past 4 yr, more than 2000 studies have been performed on patients with suspected biliary tract disease here at Montefiore Hospital and Medical Center. The Division of Nuclear Medicine now provides IDA imaging on a 24-hr, 7-day/wk basis. The images obtained usually can be interpreted by even the most naive surgeon with only a minimal background experience. The anatomy is readily identifiable and quite precise and compares favorably with that observed in contrast media cholangiography. While the primary use of IDA imaging has been in the diagnosis of acute cholecystitis, its realized and potential versatility is limited only by the imagination of the surgeon. We have also successfully used IDA imaging for evaluation of patients with jaundice, ampullary stenosis, duodenal diverticula, biliary-enteric anastomoses, and biliary leaks. In addition, nonbiliary pathol-
From the Department of Surgery, Albert Einstein College of Medicine and the Montefiore Hospital and Medical Center, Bronx, N.Y. Reprint requests should be addressed to Marvin L. Gliedman, M.D., Department of Surgery, Albert Einstein College of Medicine, Bronx, N.g. 10467. 9 1982 by Grune & Stratton, Inc. 0001- 2998/8 2/1201~00 2501.00/0
2
has also added very useful information in patients w i t h jaundice, ampullary stenosis, o b s t r u c t i n g duodenal diverticula, and certain nonbiliary problems
where pain patterns might mimic acute cholecystitis. Its availability on a 7-day, 24-hr/day basis enhances its value as well.
ogy has often been diagnosed on the hepatic, renal, or intestinal phases of the studies. ACUTE CHOLECYSTITIS
The common denominator to the development of acute cholecystitis is cystic duct obstruction. IDA imaging in the acutely ill patient has proven uniquely able to rapidly diagnose or exclude the presence of cystic duct obstruction. In a study previously published from our institution, the overall accuracy of diagnosis in 323 patients with acute cholecystitis was 97.6%. The false positive rate was 0.6% and false negative rate 4.8%) The majority of patients presenting with acute right upper quadrant pain are both very elderly and very ill. Rapid diagnosis and treatment is essential in these patients. However, fully onethird of patients, who subsequently are found to have acute cholecystitis, present with only vague or mild symptoms and signs. The abdominal examination may be nonspecific. The patient's temperature, white count, and liver function test may all be normal. 2 Modalities other than IDA imaging have been unsuccessful in more than 50% of patients in detecting pathognemonic signs of acute cholecystitis (such as a distended gallbladder with stones, or air on the wall of the gallbladder). As indicated above, failure to visualize the gallbladder within 4 hr on IDA imaging in a patient with normal biliary to bowel flow has been 98% accurate in the diagnosis of acute cholecystitis) Equally important is that visualization of the gallbladder in this same patient population has allowed us to rapidly eliminate biliary tract disease from the differential diagnosis and to move expeditiously to the identification of the proper diagnosis. The most difficult biliary tract disease to diagnose is acute acalculous cholecystitis. IDA scanning is unmatched in diagnosing this condiSeminars in Nuclear Medicine, Vol. XII, No. 1 (January), 1982
HEPATOBILIARY SCINTIGRAPHY
tion. In 14 of our 15 patients, the diagnosis was promptly established by nonvisualization of the gallbladder or nonvisualization of both the gallbladder and the common bile duct. The 15th patient visualized the gallbladder, but had no response to intravenous sincalide stimulation. The ability of IDA to correctly diagnose acute acalculous cholecystitis is additionally important because these patients are commonly in the period after unrelated surgery or posttrauma and have considerable bowel distention that often obscures ultrasound visualization of the gallbladder. ACUTE COMMON BILE DUCT OBSTRUCTION
IDA imaging has enabled us to diagnose acute common bile duct (CBD) obstruction prior to the development of jaundice or deteriorating liver function. The diagnosis can now be made prior to dilatation of the common bile duct or intrahepatic radicles and before the anatomic diagnosis of ductal dilatation can be made by ultrasound, percutaneous transhepatic cholangiography (PTC) or endoscopic retrograde cholangiopancreatography (ERCP). 3 Our early studies were all done using dimethyl IDA (HIDA). However HIDA does not visualize the biliary tract well when the bilirubin level excedes 5 mg/dl. In our experience, di-isopropyl IDA (DISIDA) allows visualization of the biliary tract up to a level of 30 mg/dl, and we now favor DISIDA for all studies. Of 323 patients who presented with acute right upper quadrant (RUQ) pain here at Montefiore Hospital and Medical Center, 27 had an IDA pattern consistent with acute CBD obstruction (i.e., good hepatic uptake with no discernable movement of the radiotracer to the intestine over a 4-hr or longer time period). In patients who had both IDA imaging and ultrasonography (within several hours of each other), ultrasonography correctly detected a dilated CBD in only 20%. Seventy percent had a normal sized CBD, and in 10% the CBD could not be detected because of dilated bowel.~ CHRONIC CHOLECYSTITIS
We have not found IDA imaging to be useful in the diagnosis of the patient with symptoms of chronic cholecystitis. While delayed visualization of the gallbladder and delayed biliary to
3
bowel transit time have been reliable indicators of chronic cholecystitis, ultrasonographic detection of stones or oral cholecystography remain our prime means of diagnosis of chronic cholecystitis. The presence of these scintigraphic findings in the acute clinical setting has helped to direct the diagnostic work up to the appropriate area. As a general rule, the routine oral cholecystogram has become reserved for the nonemergent outpatient with symptoms suggestive of gallbladder disease and is now rarely performed as an in-hospital study. The intravenous cholangiogram has virtually disappeared at our institution in the evaluation of patients with suspected biliary tract disease. JAUNDICED PATIENT
In the jaundiced patient our standard approach to identification of the point of obstruction and the cause of the obstruction remains the use of ultrasonography followed by PTC and/or ERCP. IDA scanning, however, has been useful in moderately icteric patients who do not show dilated ducts and the question of mechanical versus parenchymal disease is entertained. Because DISIDA allows visualization of the biliary tract to all levels of jaundice, it has regularly permitted the elimination of the medically jaundiced patient from consideration for surgery by showing patent biliary to bowel flow. The scan is safe, simple and noninvasive and obviates the need for PTC or ERCP in a patient with a nondilated biliary system. Although the IDA scan accurately diagnoses biliary tract obstruction, one of its limitations is its resolution, which is not descrete enough to allow an absolute differential diagnosis of stones, tumor, or lymph nodes as a cause for the obstruction. We still rely on the more anatomically specific imaging techniques to make this distinction, e.g., PTC or ERCP. Nor can information about the absolute sizes of the ductal system or the rates of excretion be accurately obtained. Hopefully, ongoing investigations with computer technology will achieve useful results in these areas. Because of its availability 24 hr/day in our institution, IDA scanning has commonly been used as the first test prior to antibiotic therapy in
4
GLIEDMAN AND WILK
presumed cholangitis and then followed, when the appropriate personnel were available, by PTC and/or ERCP prior to surgery. POSTOPERATIVE IDA SCANNING
Prior to IDA scanning, we used the upper gastrointestinal series (UGI), when feasible, to demonstrate patency of biliary-enteric anastomoses. Now, however, IDA scanning has almost replaced the UGI series for this purpose and allows an appreciation of function as well as definition of an intact anastomosis. In patients with biliary-enteric anastomoses that are remote from the duodenum and out of reach of the endoscope, IDA scanning is the only test that can demonstrate patency or occlusion of the biliary-enteric anastomosis. This is particularly applicable to the patient who is postpancreatieoduodenectomy (Whipple resection) or hepatico-jejunostomy (Rodney Smith procedure). In these patients, when.the bilirubin does not promptly fall, the IDA scan allows differentiation between continuing liver failure and an obstructed biliary-enteric anastomosis. IDA scanning has been valuable in patients with selerosing cholangitis. In one of our patients who was 2 yr postbiliary-enteric anastomosis (hepaticojejunostomy), progression of his jaundice meant that either the anastomosis was strictured or his liver parenchymal disease was progressing. Severe hepatic parenchymal disease can prevent ductal dilatation, making PTC difficult while the Roux-en-Y anastomosis generally precludes ERCP. IDA scanning showed prompt emptying into the intestine thereby identifying progression of his intrahepatic sclerosis. We have encountered leaks in a small group of patients following biliary-enteric anastomoses. Our observations indicate that IDA scanning not only identifies the leak but prognosticates the need for reoperation. Our experience to date has shown that those patients who showed some leak, but still had GI continuity and preferential
flow to the intestine, can be expected to close spontaneously. Those patients who have no GI continuity (total leak) or whose preferential flow is to a subhepatic pocket or drain site, warrant reoperation for either a new anastomosis or better drainage. IDA scanning has made the diagnosis of functional ampullary stenosis much easier and reliable. Previously, the diagnosis of ampullary stenosis was made by time-density studies using the IVC. That is, on serial cholangiograms, the CBD visualized progressively to 2-4 hr as compared to a normal peak time of 1 hr associated with rapid disappearance. Delay in excretion of IDA has proven more reliable, safer, and simpler. In a small group of patients with ampullary or periampullary duodenal diverticula, the diverticulum fills and mechanically obstructs the CBD, resulting in repeated episodes of cholangitis. IDA scanning has successfully demonstrated the sustained distention and stasis in the diverticulum by showing filling of the ampullary diverticulum with delayed CBD emptying and delayed emptying of the diverticulum. These patients have been relieved of their symptoms by choledochoduodenostomy. Finally, nonbiliary pathology has been identified. In about 10% of patients studied for acute RUQ pain, the IDA scan has eliminated the biliary tract as the source of the symptoms by visualizing the gallbladder and directing us to unsuspected nonbiliary sources of the patient's symptoms. These chance findings have included hepatomas, metastases, and hepatic abscesses in the hepatocyte phase; absence of a kidney or obstructive uropathy in the renal phase; and intraabdominal abscesses, pancreatic masses, and intestinal obstruction in the intestinal phase. 4 In summary, IDA scanning has rapidly become our most valuable diagnostic tool in the evaluation of patients with suspected biliary tract disease. It has also allowed physiologic evaluations, heretofore not available without direct interventional measurements.
REFERENCES
1. WeissmannHS, Badia J, Sugarman LA, et al: Spectrum of 9~Tc-IDAcholescintigraphypatternsin acute cholecystitis.Radiology138:167-175, 1981 2. SzlabickRE, Catlo JA, Fink-BennettD, et al: Hepatobiliary scanning in the diagnosisof acute colecystitis.Arch Surg 115:540-544, 1980
3. Weissmann HS, Sugarman LA, Freeman LM: The clinical role of technetium-99miminodiaceticacid cholescintigraphy. Nucl Med Annu 35-80, 1981 4. Weissmann HS, Sugarman LA, Frank MS, et al: Serendipity in technetium-99mdimethyliminodiaceticacid eholescintigraphy.Radiology135:449-454, 1980