The effect of prednisolone, thromboxane, and platelet-activating factor receptor antagonists on lymphocyte and platelet migration in experimental cardiac transplantation.

Three agents that significantly prolong cardiac allograft survival were tested in Lewis rats that were recipients of hearts from Lewis X Brown-Norway F1 hybrid donors. In the presence of azathioprine, the effects of daily administration of either the thromboxane antagonist (L 640,035), the platelet-activating factor (PAF) antagonist (BN 52021) or prednisolone were evaluated on the infiltration of cardiac allografts by syngeneic lymphocytes and platelets labeled with 111indium. As anticipated, platelet deposition was reduced by the thromboxane antagonist and unaffected by the PAF antagonist; the latter is likely due to the known absence of PAF receptors in rat platelets. In addition prednisolone had no effect. The increased accumulation of lymphocytes on days 4-5 was also unaffected by all three drugs. These experiments indicate that, in this model, graft survival is not necessarily related to lymphocyte and platelet infiltration of the graft. The data also provide evidence for the efficacy of the thromboxane receptor antagonist L 640,035 in preventing platelet deposition in vivo.

Detection of degenerative disease of the temporomandibular joint by bone scintigraphy: concise communication.

Nine patients with facial pain were evaluated with limited bone scans. The scintigrams correlated with microscopy in all patients (eight positive, one negative), although radiographs correlated with microscopy in only five patients (four positive, one negative). The degenerative disease process in the temporomandibular joint was more extensive in the patients with radiographic and scintigraphic abnormalities than in those with scintigraphic abnormalities alone. The limited bone scan appears useful in detecting early degenerative changes in the temporomandibular joint.

Fourier amplitude ratio: a new way to assess valvular regurgitation.

The stroke-volume ratio determined from the equilibrium gated blood-pool study has been utilized to assess valvular regurgitation, but it is difficult to get reproducible results using generally available equipment. We have developed a new approach utilizing the Fourier amplitude ratio of the left and right ventricles, which is easily implemented and reproducible. Initial clinical experience shows that 17 patients with valvular regurgitation were clearly distinguished from 30 patients without valve disease.

Bone scintigraphy: differentiating benign cortical irregularity of the distal femur from malignancy.

Two cases of benign cortical irregularity of the distal femur ( BCIDF ), which radiologically simulate malignancy, are presented. The use of bone scintigraphy in differentiating this entity from malignancy is described.

Renal scans in pregnant transplant patients.

This study demonstrates the normal technetium-99m diethylenetriaminepentaacetic acid ([99mTc]DTPA) renal scan in pregnant patients with transplanted kidneys. Five pregnant renal transplant patients had seven [99mTc]DTPA renal studies to assess allograft perfusion and function. All scans showed the uteroplacental complex. The bladder was always compressed and distorted. The transplanted kidney was frequently rotated to a more vertical position. In all patients allograft flow and function were maintained. There was calyceal retention on all studies and ureteral retention activity in three of five patients. Using the MIRD formalism, the total radiation absorbed dose to the fetus was calculated to be 271 mrad. This radiation exposure is well within NRCP limits for the fetus of radiation workers and an acceptable low risk in the management of these high risk obstetric patients.

Rapid bolus injection of gadopentetate dimeglumine: absence of side effects in normal volunteers.

The safety and tolerance of gadopentetate dimeglumine 0.1 mmol/kg when injected at a bolus rate (10 ml/15 sec; four times the recommended rate) was studied in 12 normal men between the ages of 20 and 36 years. Each of the subjects received a single injection of either gadopentetate dimeglumine (0.2 ml/kg) or a placebo (normal saline, 0.2 ml/kg), followed by a 7-day washout and a single injection of the alternative treatment (six subjects per sequence). Measurement parameters included blood pressure, pulse rate, ECG, cardiographic rhythm strips, hematology and blood chemistry evaluations, physical examinations, and adverse drug experiences. Variations of greater than or equal to +/- 15 mm Hg in diastolic blood pressure and greater than or equal to +/- 15 beats per min in heart rate were observed in some subjects after injection of either gadopentetate dimeglumine or the placebo, but no clinically significant changes from baseline were observed for any parameter. Post-gadopentetate dimeglumine results were not significantly different statistically from post-placebo results. No adverse experiences were reported for any subject. It is concluded that gadopentetate dimeglumine is safe and well tolerated when administered to normal men at a rapid injection rate of 10 ml/15 sec.

Hemodynamic effects of Gd-DTPA administered via rapid bolus or slow infusion: a study in dogs.

The hemodynamic effects of rapid (10 sec) versus slow (1 min) IV injection of Gd-DTPA were compared in normal, pentobarbital-anesthetized mongrel dogs. Hypertonic mannitol and isotonic saline were used as equiosmotic and equivolumetric controls. Two dose levels of Gd-DTPA were administered: 0.1 mmol/kg and 0.5 mmol/kg, corresponding to dose volumes of 0.2 and 1.0 ml/kg, respectively. The rapid injection of a high dose (0.5 mmol/kg) produced a transient decrease in arterial blood pressure (21 mm Hg, p less than .001), which returned to control values within 1 min after the injection. Slow IV infusion at this high dose had no statistically significant hemodynamic effects. There were no statistically significant effects of the lower dose (0.1 mmol/kg) administered as a bolus or by infusion, nor of the saline or osmotic control solutions. These results suggest that acute hemodynamic effects of Gd-DTPA are not observed at clinically relevant doses and the vasodilation observed at a higher dose may result from a direct action of the contrast agent.

Noninvasive imaging of the gastrointestinal tract.

Numerous radiographic and scintigraphic imaging modalities are now available for evaluating the gastrointestinal system. With a well-formulated plan based on patient history, physical examination, and laboratory values, together with knowledge of patient preparation techniques and consultation, an efficient customized approach to gastrointestinal disease can be accomplished.

Detection of unsuspected malignant pleural effusion by bone scan.

Technetium-99m phosphate compounds may occasionally accumulate in malignant pleural effusions. A case of metastatic pleural effusion first diagnosed by bone scan, prior to its clinical or roentgenographic detection, is reported.

Bone scintigraphy of osteoid osteoma: a clinical review.

Osteoid osteoma is a painful osteoblastic process. The pre-operative diagnosis is usually made by roentgenogram. Four surgically confirmed cases are examined where the preoperative diagnosis was clarified by bone scintigraphy. The clinical indications, the diseases process, the literature are reviewed.

The scintigraphic evaluation of hip pain in children.

Thirty-eight patients (28 boys and 10 girls) with hip pain were referred for bone scans. In 7 of 8 with Legg-Calvé-Perthes disease, there was decreased uptake of the radiopharmaceutical in the proximal femoral epiphysis; the other had radiographic evidence of joint destruction and showed increased uptake. Three patients with abnormal scans had normal x-rays with Gaucher's disease, toxic synovitis, and Legg-Calvé-Perthes disease, respectively. One patient with avascular necrosis associated with steroid therapy had increased uptake, possibly due to revascularization. Those with toxic synovitis had either normal bone scans for showed a slight generalized increase around the hip joint. It is speculated that the latter may represent those who later present with Legg-Calvé-Perthes. The bone scan is useful for the early detection of Legg-Calvé-Perthes disease in patients with hip pain.

Unusual appearance of a highly vascular lesion on Tc-99m DISIDA hepatobiliary scintigraphy.

A lesion was identified on the late images of a hepatobiliary scintigraphic study, but was not detected on the very early images, due to its enlarged blood pool. This combination of scan findings has not been previously described. The implication of the observation is that one must examine all the images of the hepatobiliary study in an effort to detect space-occupying lesions of the liver.

Variation of the spleen-liver activity ratio due to a change in position.

The ratio of splenic to hepatic activity in the posterior view of a Tc-99m SC liver-spleen scan has been used as an indicator of parenchymal disease. Analysis of liver-spleen scans from a series of patients acquired in both the supine and erect positions revealed that the spleen-liver ratio varied considerably with a change in the patient position. Qualitatively there was a shift of colloid from the liver to the spleen in five of 18 supine views and ten of 18 erect views. Quantitative analysis of 37 cases showed that the median erect spleen-liver ratio was 20% greater than the spleen-liver ratio observed in supine patients. Criteria for an abnormal spleen-liver ratio need to be established in each position.

Thallium/technetium functional imaging of the thyroid and parathyroid. A case report.

This case report demonstrates the usefulness and limitations of technetium/thallium scintigraphy in the diagnosis of parathyroid hyperplasia. In addition, discordant thyroid tracer uptake (Tc-99m but not TI-201) due to colloid cysts is described. Another perspective in the controversy over which radiopharmaceutical, Tc-99m or TI-201, should be injected first also is presented.

Atlas of hepatic arterial perfusion scintigraphy.

Tc-99m MAA intra-arterial perfusion studies are necessary to determine blood flow distribution for hepatic arterial chemotherapy. In this mini-atlas, examples selected from over 900 cases to illustrate important points to aid in a better understanding and interpretation of these studies with particular emphasis on diagnostic and therapeutic interventions are presented.