Diagnosis of uterine abnormalities with radionuclide imaging.

A pelvic hypervascular blush often creates a diagnostic dilemma during radionuclide abdominal imaging studies in females. This blush is shown to be due to uterine vascularity that is more prominent in the secretory and menstrual phases of the menstrual cycle. Significant uterine vascularity in the earlier phases is inappropriate and may be pathologic. Three such cases are presented in which increased uterine vascularity on radionuclide imaging during the proliferative phase either lead to a diagnosis or supported a clinical finding.

Radionuclide angiography in evaluation of cold solitary thyroid nodules. Improved diagnostic accuracy using flow and washout analysis.

Radionuclide thyroid angiography was performed in 252 patients with hypofunctioning thyroid nodules to evaluate differences in vascular flow and washout patterns in benign and malignant disease. Time activity curves of Tc-99m pertechnetate flow through the cold nodules were generated using region of interest software. Retention ratios of counts in the nodule at 2 minutes after radionuclide administration versus those at peak activity were derived. Patients subsequently underwent surgical excision and histopathologic examination. One hundred forty-four of the 204 benign nodules were avascular with absent radionuclide flow through the nodule. Fifty-six benign nodules were vascular with a prolonged radionuclide washout pattern with retention ratios ranging from 0.62-0.92. Forty-six of the 48 malignant nodules displayed increased perfusion with rapid radionuclide washout with retention ratios ranging from 0.28-0.48. Four benign nodules exhibited a similar flow and washout pattern. Radionuclide thyroid angiography with vascular flow and washout analysis appears to be a useful technique to differentiate between benign and malignant thyroid nodules with a high degree of sensitivity and specificity.

Evaluation of functional parameters and left ventricular size by radionuclide ventriculography (RNV) in myocardial infarction patients.

Functional parameters like left ventricular ejection fraction (LVEF), peak ejection rate (PER), peak filling rate (PFR), regional wall motion and left ventricular size index were evaluated in 68 patients with myocardial infarction and in 50 normal subjects, by radionuclide ventriculography (RNV). Patients were divided into four groups (I to IV) according to increasing left ventricular size and the parameters were evaluated in each group. LVEF proved to be the most sensitive parameter of overall left ventricular performance. PFR decreased significantly from group I to group III but not from group III to group IV, suggesting that in extreme degrees of left ventricular enlargement some compensatory mechanism acts to prevent a greater fall in left ventricular compliance. LV size and performance were least affected in inferior wall myocardial infarction. LVEF was however a better predictor of LV size than the site of the myocardial infarction.

Differentiation between suppressed thyroid tissue and thyroid hemiagenesis with Tc-99m pertechnetate radionuclide angiography.

Tc-99m pertechnetate thyroid angiography was performed on 62 patients who had unilateral thyroid enlargement and no radionuclide uptake in the contralateral lobe in an attempt to differentiate suppressed thyroid tissue from thyroidal hemiagenesis. In 55 cases of toxic, autonomous functioning thyroid nodules, the suppressed contralateral lobe was unequivocally demonstrated, the flow study showing tracer coursing through this tissue in the sequential arterial images. No arterial flow was demonstrable on the rapid sequence imaging in the agenetic lobe in seven patients who had thyroidal hemiagenesis. Radionuclide thyroid angiography appears a safe, simple, and accurate one-step study for distinguishing between suppressed thyroid tissue and thyroid hemiagenesis and precludes the requirement for additional studies, such as the thyrotropin stimulation test and Tl-201 scintigraphy.

Technetium-99m radiocolloid scintigraphy, planar and SPECT red blood cell imaging and ultrasonography in diagnosis of hepatic hemangioma.

Technetium-99m planar sulfur colloid scintigraphy, red blood cell imaging and ultrasonography were performed in eighteen patients of hepatic hemangioma to evaluate their diagnostic utility. Radiocolloid scans detected fourteen hemangiomas in 12 patients as focal hepatic defects but missed 9 lesions smaller than 2.5 cm in the other 6 patients, accounting for a 61% sensitivity. All 23 lesions were avascular or normovascular on radionuclide flow study. Serial planar red blood cell scintigraphy showed characteristic gradually increasing focal isotopic accumulation in the 14 hemangiomas which had identifiable cold areas on the radiocolloid study. One of 6 patients with normal radiocolloid scan also showed the typical increasing blood pool pattern of hemangioma, five had normal planar scans till 1 1/2 hours. SPECT red blood cell imaging in these 5 patients detected an additional seven hemangiomas. All 7 lesions were smaller than 2.5 cm. One 1.5 cm hemangioma was missed on both planar and SPECT red blood cell imaging. Region of interest ratios in SPECT transaxial images confirmed gradually increasing concentration of labeled red blood cells in the lesions. Ultrasonography detected 22 of the 23 hemangiomas. Ten were hyperechoic, average size 2.25 cm. Twelve were of mixed pattern, generally larger, average size 7.2 cm. Sonography is useful in the detection of hepatic hemangiomas as a focal mass lesion, but the variable sonographic appearance precludes a definite pathological diagnosis. Technetium-99m red blood cell imaging appears a sensitive technique in detection of hepatic hemangioma, with SPECT being especially useful in locating smaller lesions. The addition of useful in locating smaller lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

99mTc(Cu)-mannitol complex: a new agent for dynamic renal function studies.

Mannitol has been labeled with 99mTc by using cuprous chloride as a reducing agent. Blood and kidney clearance of 99mTc(Cu)-mannitol was slightly faster than that of 99mTc(Sn)-DPTA in rat and maximum radioactivity ratio of kidneys to blood was 84.6 at 5 min. A comparative study of 99mTc(Cu)-mannitol, 99mTc(Sn)-DTPA was made in rabbits by taking serial images of kidneys and bladder with a gamma camera. Results show superiority of 99mTc(Cu)-mannitol over other agents for dynamic renal function studies.

Computer-assisted radionuclide perfusion study in solitary cold thyroid nodules for diagnosis of malignancy.

A computer-assisted radionuclide perfusion study was performed in 25 cases of solitary 'cold' thyroid nodules to assess their vascularity relative to that of normal adjoining thyroid tissue. Hypervascularity was seen in 3 malignant nodules; 1 follicular adenoma also showed increased vascularity. The 21 nodules demonstrating equal vascularity or avascularity with respect to normal thyroid tissue were benign in nature. Computer-generated time-activity curves were helpful in distinguishing hypervascular from equally vascular nodules. This technique, in conjunction with clinical evaluation, can be of value in deciding whether patients should undergo surgery or receive conservative management.