Clinical comparison of 99mTc-labeled preformed phytate colloid and sulfur colloid: concise communication.

An in vitro preformed colloid preparation of 99mTc-Sn-phytate was compared both qualitatively and quantitatively with a commercial 99mTc-sulfur colloid kit in 30 patients. The degree of liver and spleen deposition of radiocolloid was, for practical purposes, the same. A slightly higher background was visually noted in 33% of the patients receiving preformed colloidal 99mTc-Sn-phytate, but it did not interfere with the diagnostic quality of the liver and spleen images. The only advantage of the phytate compound was a preparation time of less than 5 min.

Technetium-99m red blood cell venography in patients with clinically suspected deep vein thrombosis: a prospective study.

We have compared technetium-99m (99mTc) red blood cell (RBC) venography to serial impedance plethysmography (IPG) in 110 consecutive patients with a first episode of clinically suspected deep vein thrombosis (DVT). IPG was performed at Day 0 and, if abnormal, contrast venography was also performed to rule out a falsely positive result. Patients with an initially normal IPG had the test repeated at Days 1, 3, 5 to 7, and 10 to 14. Contrast venography was not performed and anticoagulant treatment was withheld in all patients who remained normal during repeated IPG testing. Technetium-99m RBC venography was performed at Day 0 in patients with an initially abnormal IPG and during the period of serial IPG testing in those with an initially normal IPG. The sensitivity of [99mTc]RBC venography for proximal DVT was 0.68, with 95% confidence limits (CL) from 0.48 to 0.89. Specificity was 0.88 (95% CL from 0.81 to 0.95). When the findings of [99mTc]RBC venography for the entire lower extremity were compared to the reference method, the sensitivity increased to 0.90 (95% CL from 0.82 to 0.97) but the specificity decreased to 0.56 (95% CL from 0.51 to 0.62). Technetium-99m RBC venography is a sensitive but less specific method for detecting DVT of the entire lower extremity. An abnormal [99mTc]RBC venogram, particularly in the calf region, should always be confirmed by another diagnostic method.

Selective right ventricular dysfunction after coronary artery bypass grafting.

Preoperative and postoperative right (RVEF) and left ventricular ejection fractions (LVEF) were studied by means of radionuclide techniques in 15 patients undergoing coronary bypass operations. Three of them, all with right coronary artery lesions, had postoperative depression of RVEF without concomitant decrease in LVEF. In contrast to those with left ventricular dysfunction, the patients with selective RVEF depression did not have significant elevation of myocardial injury index calculated from creatine kinase isoenzyme (CK-MB) curves.

Quantitative scintigraphy using radiophosphate and radiogallium in patients with rheumatoid arthritis.

Quantitative scintigraphy of the wrist, MCP, and knee joints in patients with RA was performed using Tc-99m-MDP and Ga-67 citrate. Radiopharmaceutical uptake in affected joints was compared with uptake at 2 control reference sites (juxta-articular bone and soft tissue). Following a 6-week course of therapy with Sulindac, the patients' overall assessment of disease was improved, but the results of joint/bone and joint/soft tissue ratios were variable. Improvement using Tc-99m-MDP during the first 2 weeks of NSAID therapy was noted in the minimally inflamed wrist by joint/soft tissue measurement and in the maximally affected MCP joint by joint/bone ratio. There was no change in the joint ratios employing the Ga-67 citrate radiopharmaceutical. The initial qualitative score assigned to a joint using Tc-99m-MDP was in agreement with the calculated quantitative ratio except for the knee joint. Our results suggest that quantitative scintigraphy in its present format cannot be used as a reliable indicator to monitor the course of rheumatoid arthritis during NSAID therapy and subjective measurements are still the best judge of effective treatment.

Systemic amyloidosis involving the diaphragm and acute massive hydrothorax during peritoneal dialysis.

Hydrothorax secondary to trans-diaphragmatic fluid leakage through a peritoneo-pleural communication is an occasional, potentially serious complication of peritoneal dialysis. The etiology of this condition is not clear, being thought to be due either to congenital or acquired diaphragmatic fenestrations or acquired scarcity of muscle fibers in the tendinous part of the diaphragm which are compounded by increased intra-abdominal pressure during the dwell period of peritoneal dialysis. We report a 54-year-old woman who developed irreversible acute renal failure from adjuvant chemotherapy for ovarian cancer previously resected surgically. Three days after the onset of continuous ambulatory peritoneal dialysis, she developed acute respiratory distress associated with a massive right hydrothorax secondary to a peritoneo-pleural communication demonstrated by scintigraphy. At autopsy 2 weeks later, systemic amyloidosis was surprisingly found and histologic examination of the right hemidiaphragm showed the presence of amyloid, among sparse muscle fibers. This is the first case report of a distinct pathological process, i.e. amyloidosis, involving the diaphragm associated with a peritoneo-pleural communication causing massive hydrothorax at the onset of peritoneal dialysis.

A clinical comparison of MDP and DMAD.

Tc-99m labeled dimethyl-amino-diphosphonate (DMAD) was compared with methylene diphosphonate (MDP) in five healthy volunteers and 28 patients with a variety of bony afflictions. Although the normal bone uptake of DMAD is less than MDP, the lesion-to-normal bone ratio is significantly higher with DMAD. All 71 lesions detected with MDP were also seen with DMAD. However, 10 lesions were disclosed with DMAD that were not seen with MDP. These lesions tended to have low grade concentrations of the radiopharmaceutical and were detected with DMAD by virtue of the lower normal bone uptake rather than higher lesion uptake.

Assessment of the utility of gallbladder imaging with 99mTc-IDA.

Cholescintigraphy was performed in 113 patients of whom 38 had normal gallbladders, 37 had acute cholecystitis and 38 had chronic cholecystitis. The radiopharmaceuticals used in the study were either 99mTc-dimethyl acetanilide iminodiacetic acid or 99mTc-paraisopropyl acetanilide iminodiacetic acid, both of which performed equally well. All patients with non-visualized gallbladders had cholecystitis, but visualization did not exclude disease. The rapidity of obtaining the results (within one hour), the complete absence of untoward reactions to the radiopharmaceuticals, the much lower frequency of subtle or indeterminate results, the ability to render useful information in the presence of moderate jaundice and the lack of interference from overlying intestinal contents establishes these radionuclide agents as superior to both radiographic oral and intravenous cholangiography in the investigation of the acute abdomen.

Differential diagnosis of jaundice by 99mTc-IDA hepatobiliary imaging.

The utility of 99mTc-IDA imaging in the differential diagnosis of jaundice was assessed. Although overall accuracy was 84%, this method is still inferior to the reported efficiency of ultrasonography and CT in making the correct diagnosis. Radionuclide imaging is a good alternative when these other modalities are not available and it functions well in an adjuvant capacity. The diagnostic limitations of 99mTc-dimethyl IDA imaging in cases of moderate to severe jaundice are largely overcome by the use of 99mTc-p-butyl IDA.

Radionuclide esophageal transit studies in progressive systemic sclerosis: an analysis of longitudinal data.

Nineteen patients with progressive systemic sclerosis (PSS) were studied by radionuclide esophageal transit (ET) and followed longitudinally for 3 to 5 years. Results were expressed as percent retention at 20 s and 10 min. There was gradual deterioration of ET at both 20 s and 10 min. When results were grouped into quartiles, deterioration occurred in 58.5% of followup studies in patients who initially had potential to deteriorate regarding 20 s retention and in 48% of similar patients regarding 10 min retention.

A crossover study comparing delayed radiohippurate images with furosemide renograms.

109 kidneys in 56 adult patients suspected of having urinary tract obstruction were studied prospectively. All patients underwent a routine 131I-hippurate series for 30 min, and to this was added a delayed image at 2 h. Later in the same day, these patients had a diuretic renogram for the first 30 min in which 40 mg of furosemide were injected simultaneously with a repeat 131I-hippurate dose. In 48 patients (85.7%) the delayed image and diuretic renogram showed mutual agreement as to the presence or absence of urinary tract obstruction, but not necessarily with the final diagnosis. Of the 8 remaining patients with 16 kidneys, there were 6 false positives and 4 false-negatives by diuretic renography, and 1 false positive and no false-negatives by nondiuretic delayed imaging. The only benefit derived from the diuretic renogram was a shortening of the examination from 2 h to 30 min.

Kupffer cell depletion associated with capillarization of liver sinusoids in carbon tetrachloride-induced rat liver cirrhosis.

Rats were made cirrhotic by carbon tetrachloride inhalation associated with phenobarbital in the drinking water over 10 weeks. After a 1-week recovery period a 99mTc sulphur colloid radioisotope scan of the liver was carried out on each animal following bolus injection into the iliac vein. Kupffer cells were then histologically identified by one of three methods: colloidal carbon uptake, iron staining after ferritin-dextran, or endogenous peroxidase staining. The degree of liver injury was classified into four pathological groups and these were correlated with the phagocytic capacity of each liver as recorded on the isotope scan. All three histological markers demonstrated that in normal liver, Kupffer cells are more plentiful in periportal areas. In cirrhotic liver, there were very few Kupffer cells in nodular regenerative areas, where continuous capillaries are found, but Kupffer cells were present in the remaining more normal trabecular-sinusoidal areas. Morphometric counting of carbon- and ferritin-labelled Kupffer cells demonstrated a significant decrease in cirrhotic livers. A close correlation was also found between increasing degree of liver injury and diminished hepatic phagocytic capacity, as demonstrated by the radioisotope scan. The study demonstrates that where regenerative liver is capillarized, with replacement of fenestrated sinusoids, Kupffer cells are absent.

Effect of 99mTc-Sn-colloid incubation time on in vivo distribution.

The in vitro particle size of 99mTc-Sn-colloid preparation increases with the length of incubation time after reconstitution. It was found that the percentage of particles trapped (T) by a 1-micron filter as a function of time (t) could be represented by the logarithmic equation T = 5.3 + 15.7 ln t (r = 0.96). This material was applied to a crossover study involving 25 patients each of whom received preparations of the same reconstituted 99mTc-Sn-colloid that had been incubated for 15 min and (each patient received both) 5 h. It was found that there was a significant shift of radioactivity to the spleen and a significant decrease in background with the material that had been incubated longer. The 99mTc-Sn-colloid is adequate for the disclosure of space-occupying disease in the liver and spleen, but unreliable for drawing conclusions on the status of liver function based on the changes in splenic concentration.

99mTc-IDA imaging in the differential diagnosis of acute cholecystitis and acute pancreatitis.

99mTc-IDA (99mTc-dimethyl-acetanilide-iminodiacetic acid) hepato-biliary imaging was evaluated for its efficacy in distinguishing acute cholecystitis from acute pancreatitis. In a retrospective review, gallbladders were demonstrated by 99mTc-IDA in 13 of 15 patients (87%) with acute pancreatitis. This is significantly higher than reports on the frequency of gallbladder filling with oral and intravenous cholangiography in the presence of acute cholecystitis.