Technetium-99m glucoheptonate renal scan in diagnosis of acute renal injury

TECHNETIUM-99m GLUCOHEPTONATE RENAL SCAN IN DIAGNOSIS OF ACUTE RENAL INJURY RICHARD T . CHOPP, M .D . H . HEKMAT-RAVAN, M .D . ROBERT MENDEZ, M .D . From the Departments of Urology and Radiology, University of Southern California Medical Center, Los Angeles . California

ABSTRACT -- Twenty-four patients with suspected renal injury were evaluated using high-dose intravenous pyelography, technetium-99m glucoheptonate radionuclide studies (RNS), and selective renal arteriography . Critical examination of these three diagnostic modalities reveal that BNS are extremely accurate in renal trauma evaluation and are more sensitive than intravenous pyelography . When RNS are used in conjunction with high-dose intravenous pyelography in the initial workup for renal trauma, 60 to 6.5 per cent of diagnostic angiogram .s may be avoided .

The difficulty in assessing the degree of parenchymal injury after renal trauma has caused a great deal of controversy in the past several years . Opinion has been divided between conservative observation and early operation . However, most authors stress the need for accuracy in assessing the location and extent of renal injury before planning management .' -3 The purpose of our study was to evaluate and compare the usefulness of technetium-99m glucoheptonate renal scan high-dose intravenous pyelography, and selective arteriography as a means of providing diagnostic information for the proper management of traumatic renal injury . Material and Methods Twenty-four patients (20 males and 4 females), eighteen to thirty-six years' old, admitted to our institution with signs of renal injury, were evaluated . These patients had sustained both blunt (8 patients) and penetrating injuries (16 patients) shortly before admission . In all instances the patients had either gross or microscopic hematuria, and a urologic evaluation was initiated on that basis . After the patients were examined and found to be stable and

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able to undergo further diagnostic procedures, appropriate blood studies were done, and the patients were transferred to the radiology department for further tests . A high-dose intravenous pyelogram (IVP) (100 cc . of contrast medium) with tomograms was the first test to be done . This was followed by the radionuclide scan . The patient was placed in the supine position on a plastic examining table . A 20 mCi . dose of technetium-99m glucoheptonate was injected into an antecubital vein in the bolus form . The dynamic phase of the study was performed by using the low-energy, all-purpose, parallel hole collimator . Three-second serial Polaroid camera films were obtained for eight to nine frames . Two or three sequential static images accumulating 300 thousand counts were then performed . Delayed images at thirty and sixty minutes postinjection were then obtained using the high resolution converging collimator . Each kidney was imaged separately in posterior and both oblique directions, when indicated, accumulating 300 thousand counts each . The patients were then transferred to the angiography suite and transfemoral selective renal angiography was performed by the method described by Halpern .' These studies were all

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L

1 hr . FIGURE 1 .

Case 1 : (A) IVP, (B) static inuege, and

(C) angiograni .

seen in the ureter (Fig . IA) . The renal scan revealed a defect of the left lower pole (Fig . IB) which was found to be an arteriovenous fistula on angiography (Fig . 1C) .

Case 2 A twenty-one-year-old man received blunt trauma to his right flank in an automobile accident . He was admitted with gross hematuria . IVP revealed a normal left kidney, and the right kidney had obvious gross extrrvasation of dye, hazy outlines, and poor visualization of the collecting system (Fig . 2A) . Renal scan revealed a fracture through the upper pole but with good flow to each section (Fig . 2B) . This nondisplaced fracture was confirmed by angiography (Fig . 2C) .

Case 3 A twenty-five-year-old man sustained a gunshot wound to the left upper abdominal quadrant with subsequent gross hematuria . Highdose IVP revealed loss of the renal outline of the left upper pole (Fig . 3A) . This was noted as a real defect by renal scan (Fig . 3B) and was confirmed by arteriogram (Fig . 3C) . Results In analyzing the results we were most in-

performed on the patients within eight admission . Three representative cases are preseu Case Reports Case I A thirty-eight-year-old woman lust stab wound to the left flank with sub gross hematuria. A high-dose IVP reveal kidney with filling defects and some fur, the lower collecting system . Clots al

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r~ ; of ere

.v

terested in detennining the sensitivity (injury present-positive test) and the specificity (no injury-negative test) of the three diagnostic modalities . The other point of interest was whether the IVP, in combination with the RN S, would give enough information about the extent of injury to either obviate the need for angiography or to indicate which patients needed a more definitive study such as angiography . Of the 24 cases evaluated, 17 were found to have demonstrable renal injury by angiography

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FIGURE 2 . Cas 2 : (A) IVP, (B) (C) angiograni .

static image, and

(Table 1) . Of the 17 cases, 16 had positive renal scans, while only 11 of the 17 had positive findings on IVPs . The one negative scan in this group was in a patient who was found to have a 2-cm . pericapsular hematoma on angiography . The IVY showed only a 64-per cent (11/17) sensitivity compared to 94 per cent (16/17) for the renal scan . Further analysis revealed that the angiogram on these 17 cases gave us additional useful information in only 6 cases which was not available on the IVP and scan . Case 1 was an example where an arteriovenous fistula was revealed . In this group of 17 cases of proved injury, the renal scan was positive in 5 cases in which the urogram revealed no injury or was equivocal . In all instances of a positive urographic finding, the scan was always positive as was the arteriogram . Additionally, when the IVP and renal scan revealed a major type of defect, such as Case 2 or 3 with fractures, wedge

TABLE I .

Evaluationn of patients with (I7)

with no

and

Findings With injury (17 ; Positive Negative Equivocal With no renal injury (7) Positive Negative Equivocal

IVP

(7) renal injury

Scan

11

16

1 5

1

1 1 5

If 6

Angiogram

Additional Information From Angiogram

17*

6

7f

- One

case with 2+ :'n . pericapsidar hematoma . tone cue with .m¢iograai done before scam .

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20 :3

FrcuRE 3. Case 3 : (A) 1VP, (B) static image, and (C) angiogram .

injury was 87 per cent (6/7) . The IVP was negative in only 1 of the 7 cases, positive in 1 case, and equivocal in 5 patients . Comment Accurate diagnosis of the extent of renal injury remains the cornerstone of appropriate therapy . As with most renal pathology, radiographic assessment provides the primary method of diagnosis and especially in renal trauma provides the basis for management . Over the years since the retrograde pyelogram defects, or major disruption, the angiogram always indicated the exact nature of the problem . Of the 7 cases in which there was no injury demonstrated by angiography, the RNS was negative in 6 and positive in 1 (Table I) . Analysis of that 1 case revealed that the arteriogram, which was normal, had been done only hours before the scan . The scan revealed diffuse, spotty areas of under-perfusion . We believe this finding was due to the selective renal arteriogram producing transient vascular changes or spasms in the kidney which were reflected in the scan . The specificity of the scan with no

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was a major diagnostic tool in trauma,' antegrade pyelography has evolved to be one of the better diagnostic tests . However, the routine IVP still is only 30 to 50 per cent accurate in diagnosis .' The accuracy can he increased with high doses of dye and by the addition of tomography .' This, however, leaves a large portion of patients in whom a diagnosis is still inexact . It was realized in the early 1960s that radioisotope scanning probably had a place in the diagnosis and management of renal traumas , ' However, aortography and selective renal angiography were coining into vogue at that time, and therefore renal scanning was not seriously accepted as a routine diagnostic

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modality . Adding to the dilemma was the fact that until the late 1960s and early 1970s, only isotope compounds of mercury were available for scanning . These compounds were usually bound to ehlormerodrin which was retained by the kidney for several weeks, delivering 5 to 10 rads of exposure to the kidney . It was evident, however . from work done at that time that radionuclide studies would be valuable adjuncts in diagnosis .''''" However, additional agents were needed with shorter half lives, less protein-binding, and better perfusion and morphologic defining properties . The addition of technetium-99m to the radionuclides greatly accelerated its use in renal studies ." , " The most common early application of RNS angiography was in the evaluation of carotid intracerebral circulation ; it was subsequently found to have excellent application in following renal transplant acceptance or rejection ." Since then various forms of s 9 "Tc have been developed and used for measurements of glomerular filtration rate, renal perfusion, morphology, and function ." The natural evolution led to its application in trauma . Berg" reported on 52 patients with blunt renal trauma using 99m Te-DTPA-Fe ascorbate as the active agent . After corroboration with IVP and angiography, he believed that contusions, lacerations, and avulsions could be delineated with this agent . This was an important contribution to the use of newer radionuclides in studying renal trauma and is further amplified by this report . The procedure itself has two components . The dynamic perfusion phase provides vascular flow information, and the static phase reveals renal cortical tubular concentration and glomerular filtration images . The relative vascularity of' a lesion identified on the scan can be inferred from the amount of radionuclide flowing to the lesion compared with the amount of radionuclide flowing to the surrounding or opposite kidney . The static portion of the study is the most important part and will give excellent anatomic figures which are easily seen . In our series several points are important . The IVP, even of the high-dose variety, is not as sensitive as renal scanning or angiography . However, it should remain as the primary screening test in the workup of renal trauma . If the IVP is completely and unequivocally normal, no firrther tests need be done . However, in cases in which the IVP is equivocal or unclear, the addition of RNS appears to be of benefit . Radionuclide angiography is not a sub-

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stitute for contrast angiography which is more precise and yields more anatomic information . However, disclosures by the RNS method often may be sufficient to preclude contrast angiography in diagnosis . A normal study offers important reassurance by excluding the presence of serious renal injury while the procedure can identify those patients with abnormalities who would benefit from more definitive studies, such as selective renal angiography (Case 2) . The nature of the contrast angiographic procedure does not lend itself to the performance of repeated studies . On the other hand, the ease and harmlessness of scanning make it ideal for serial follow-up studies, if needed . Therefore, the IVP is followed by RNS if needed and then to angiography if the RNS indicates the need for additional information, In our series of 17 positive angiograms, the IVP mid RNS were sufficient for treatment, be it conservative or surgical in 11 patients . Therefore, 11 of 17, or 65 per cent of the angiograms theoretically would not have been needed to institute correct management in our opinion . Summary Twenty-four cases of renal trauma are presented in which technetium-99m glucoheptonate renal scans were performed . Comparative evaluations between the isotopic procedure and intravenous urography as well as renal angiography are made, The technetium-99m glucoheptonatc renal scan appears to be a highly sensitive and useful examination in combination with IVP for the evaluation of patients with renal injury . There is an excellent correlation of positive findings between the renal scan and renal angiography . A positive scan indicating serious injury can be confirmed by renal angiography . In the face of a negative scan, the renal angiogram probably will be negative . If the RNS show a peripheral lesion (Case 3) and the patient is stable, or if the RNS are negative with an equivocal IVP, angiography does not appear to be necessary . Because of its safety and ease of performance for both physician and patient, it can be repeated as often as needed for followup studies . Its use in patients with renal trauma is recommended as a routine procedure . Certainly more studies are indicated to substantiate further these findings . However, radionuclide angiography appears to be a valuable adjunct in diagnosis of renal trauma .

2(15

Los Angeles County General Hospital 1200 North State Street Los Angeles, California 90033 (DR . CHOPP)

References 1 . Mendez R : Renal trauma, J . Urol . 118 :198 (1977) . 2. Hodges CV, Gilbert DR . and Scott WW : Renal trauma : a study of 71 cases, ibid. 66 : 627 (1951) . 3. Kazim M, Swanson L, and Cockett A : Renal scan : the test of choice in renal trauma, ibid . 97 : 189 (1967) . 4. Halpern M : Angiography in renal trauma, Surg . Clin . North Am . 48 : 1221 (1968). 5. Swan RHJ : Injuries of the kidney, Br . J . Urol . 12 : 161 (1940) . 6, Mahoney SA, and Persky L : Intravenous drip nephrotomog-

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raphy as an adjunct in the evaluation of renal injury, J . Urol . 99 : 513(1968) . . Morrow J, and Mendez R : Renal trauma, ibid . 104 : 649 7 (1970) . 8 . Woodruff J, Cockett A, Cannon R, and Swanson L : Radiologic aspects of renal trauma with emphasis on mtedography and renal isotope scanning, ibid . 97: 649 (1970) . 9 . Winter C : Applications of the scintillation camera in urology, ibid . 104 : 649 (1970) . 10 . Steigman J, and Richards P : Chemistry of technetimn-99m, Semin . Nucl . Med. 4 : 269 (1974) . 11 . Moroff L, and Freedman C : Radionuclide angiography, ibid . 6 : 217 (1976). 12 . Freedman GS, Schiff M, and Zegcr P : The temporal and pathological significance of perfusion £allure following renal transplantation, Radiology 114 : 649 (1975) . 13 . Chervu LR, Freemen LM, and Blaufoz MD : Radiopharmaceuticals for renal studies, Semin . Nucl . Med. 4 : .3 (1974). 14 . Berg B : Radionuclide studies after urinary tract injury, ibid . 4 : 371 (1974).

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