Eddy K. Dunn

Scintigraphic differentiation of bone infarction from osteomyelitis in children with sickle cell disease

Bone scans or bone marrow scans or both were obtained during 42 episodes of bone pain in 40 children with sickle cell disease, and the usefulness of these procedures was compared. On the basis of the subsequent clinical course, a diagnosis of bone infarction was made in 34 episodes, and osteomyelitis in eight. Among 22 patients with bone infarction, uptake on bone scan was increased in 14, decreased in three, and normal in five. Seven of eight patients with osteomyelitis had increased uptake on bone scan; one had normal uptake. In contrast, marrow scan uptake was markedly decreased in 15 of 16 patients with bone infarction, and was normal in five of five patients with osteomyelitis. Thus, decreased uptake on bone marrow scan in a patient with sickle cell disease and bone pain almost invariably indicates infarction, whereas normal uptake strongly suggests the diagnosis of osteomyelitis. We found marrow scans more useful than bone scans for this differential diagnosis.

Pitfalls and limitations of diuretic renography.

We report five pediatric cases that illustrate the methodologic pitfalls and limitations of diuretic renography in suspected ureteropelvic junction obstruction. False positive studies may be related to such avoidable flaws in methodology as premature diuretic administration, inadequate diuretic dose, and bladder distension, or to recent pyeloplasty. False-negative results may occur despite optimum technique, necessitating a follow-up study for confirmation.

Radioisotopic evaluation of renal transplants.

Owing to the noninvasive nature, ready availability, and efficacy, radionuclide studies remain widely utilized following renal transplantation for monitoring changes in the functional status and detection of detrimental complications of the grafted kidney. Whereas surgical complications, including vascular occlusion, urine extravasation, drainage obstruction, hematoma, or lymphocele formation, can often be detected effectively, specification of other underlying causes of deterioration of parenchymal function, including acute tubular necrosis (ATN), various types of rejection, and cyclosporine A nephrotoxicity (CyA-NT), frequently cannot be derived independently from the findings of a study without clinical correlation. Besides imaging, plotting of renogram or time/activity curves, numerous quantitative methods have been introduced to provide objective measurements of the blood flow, as well as to gauge the capability of concentration and excretion of the transplanted kidneys. However, the findings whether qualitative or quantitative all have overlapping zones. There is no abnormal image, graphic, or numeric index absolutely specific for any of the possible posttransplant renal parenchymal complications. The differentiation of such conditions may best be achieved through chronologic association of the sequential changes, with or without quantification, detected in serial studies with the clinical presentation and findings.

Ileal Leiomyosarcoma and Leiomyoma: False-Positive Scintiscans for Meckel??s Diverticulum

Two cases of Heal leiomyomatous neoplasms with positive scintigraphic findings for Meckels diverticulum are presented. The precise mechanism for the abnormal concentration of the Tc-99m pertechnetate is uncertain. Illustrations of the collating barium and computerized tomographic studies are included and the scanning technique utilized is reviewed.

Scintiscan for acute intrascrotal conditions.

The efficacy and merit of testicular imaging, utilizing Tc-99m pertechnetate, were studied prospectively in a group of patients who presented with acute onset of scrotal pain. Consecutive admissions were studied. All were managed according to the likelihood of the problem being testicular torsion, which was determined from the clinical history, physical examination and the routine laboratory data. The final diagnostic outcome, whether by surgical exploration or clinical progress with conservative treatment, is collated with the preoperative scintigraphic interpretations, made with respect to predefined criteria. Analysis of the pretreatment images obtained in 57 patients shows that the radionuclide study is highly reliable in cases of testicular torsion and epididymo-orchitis. It appears to be much less dependable, however, in the other acute scrotal conditions. Torsions that are intermittent in nature or corrected manually apparently can have variable presentations. Certain difficulties and potential pitfalls encountered in interpreting the scintigraphic studies are discussed.

Testicular scintigraphic findings two to three months after torsion. Correlation with sonography and histopathology.

A patient with a nontender testicular mass had sonographic abnormalities compatible with but not entirely typical of a chronic torsion. His scintigraphic studies, done on the same day as ultrasonography and 1 month later, revealed only findings consistent with a very mild subsiding scrotal inflammatory process. On surgical exploration and pathologic examination, it was found that he had an organizing infarct of the testicle secondary to torsion. The clinical history, diagnostic studies, and microscopic slides of the surgical specimen were reviewed. It appeared that tissue granulation and lipogranulomatous changes in the epididymis, known histologic sequelae to the unusually prolonged testicular torsion of 2-3 months, produced scintigraphic findings different from those which have been described for a late or an atrophic torsion.

Attempts at clarification of splenic visualization on reticuloendothelial images: Tc-99m DISIDA compared with heat- denatured Tc-99m RBC imaging.

Four patients with enlarged left hepatic lobes and questionable or difficult splenic visualization on Tc-99m sulphur colloid (SC) images were further examined with additional radionuclide procedures. All four patients had Tc-99m DISIDA imaging, and three of them also had heat-denatured Tc-99m RBC imaging. The hepatobiliary images appear very effective in confirming postsplenectomy expanded enlargement of the left lobe of the liver and in refuting the presence of spleen in such cases. However, distinct visualization of the spleen in these patients can be achieved only through selective spleen imaging with heat-damaged red cells.

Scintigraphic demonstration of postural induced drainage stasis in an en bloc renal allograft.

Within 6 months after an en bloc transplantation of two kidneys from a cadaveric pediatric donor, the recipient was referred for further scintigraphic evaluation because of clinical suspicion of having a postural related function impairment of the grafted kidneys. Tc-99m MAG3 imaging, modified by varying the position of the patient during the procedure, resulted in detection of drainage stasis only with the patient standing. This drainage stasis had not been appreciated in the preceding routine examinations performed with the patient supine. Although the positional outflow stasis by itself may not be severe enough to cause alarming dysfunction of the grafted kidneys, it could conceivably be a significant contributing factor.

Oversized bullseye with central activity : a scintigraphic appearance of hemorrhagic testicular infarct following traumatic rupture of the testicle

Tc-99m pertechnetate testicular scintigraphy and corresponding sonography were performed on a 31 -year-old prisoner 9 days after he was kicked in the scrotum. Surgical exploration the following day revealed a hemorrhagic testicular infarct with rupture of the testicle. Unlike a vascular occlusive infarct of the testis secondary to torsion of the spermatic cord, the scintigraphic «bullseye» was much larger than usual and showed presence of some activity within or overlying its central zone of photopenia. Sonography revealed abnormal features highly suggestive of a traumatic testicular rupture. However, the extent of the infarct could not be as readily appreciated sonographically as with the scintigraphic images

Tc-99m MAG3 evaluation of recipients with dual adult cadaveric renal allografts. Simultaneous transplantation of both kidneys from marginal donors.

PURPOSE The application of Tc-99m mercaptoacetyl triglycine (MAG3) renal scintigraphy in patients who had simultaneous unilateral retroperitoneal transplant of both kidneys from marginal adult cadaveric donors is assessed. METHODS Eighteen patients who had this unusual form of kidney transplant were monitored and evaluated by Tc-99m MAG3 renal scintigraphy. More than 60 of the radioisotopic studies, including immediate postoperative and subsequent follow-up examinations, were performed among these patients. RESULTS In all the studies, the two transplanted kidneys were not equally well visualized by this scintigraphic procedure because of the inherent difference in their depth from the body surface, a feature of this particular surgical design. Despite this limitation, the efficacy of the scintigraphic procedure for such dual renal allografts appears to be similar to that established for kidney transplants performed in the conventional manner. CONCLUSION To use the scintigraphic procedure effectively, certain sensible and logical adjustments are needed for the comparative visual and semiquantitative assessments of the two kidneys in this special form of transplantation.