111In platelet scintigraphy for the noninvasive detection of carotid plaque thrombosis.

BACKGROUND AND PURPOSE: Thrombosis on atherosclerotic lesions in the large extracranial arteries is the main cause of embolization in the distal cerebral circulation and thus is involved in the pathogenesis of ischemic stroke. The assessment of biological characteristics of lesions that are predictive of thrombotic complications might help in stratification of the risk for stroke but is currently imperfect. METHODS: We compared the performance of (111)In-platelet scintigraphy with blood pool subtraction, ultrasound-based tissue texture analyses, and transcranial Doppler techniques in their ability to predict the occurrence of superficial thrombosis or the presence of a lipid pool in carotid artery plaque specimens removed at the time of carotid endarterectomy in 22 patients with unilateral carotid artery stenosis of >70%. RESULTS: Positivity at (111)In-platelet scintigraphy was present in 8 patients and correctly identified the presence of thrombosis superimposed on a complicated plaque. Neither tissue texture analysis nor emboli detection by transcranial Doppler, performed in 12 patients, significantly identified plaque thrombosis. None of the techniques used were able to detect the presence of a significant lipid pool inside the plaque. CONCLUSIONS: Indium-platelet scintigraphy is an accurate noninvasive diagnostic tool to detect thrombotic complications in carotid plaques. Prospective studies should assess its ultimate value in risk stratification, possibly to guide the decision of whether to perform endarterectomy in selected patient categories.

Sentinel node biopsy in clinical stage 1 melanoma: rationale for restaging and follow-up.

Lymph node involvement appears to be the most significant prognostic factor in patients affected by melanoma and has been shown to reduce the five-year survival by 40%. We studied 31 patients (15 M; 16 F; age range, 28-83 years) with clinical stage 1 (CS1) intermediate thickness (0.75-4 mm) melanoma. Scintigraphic examination of the nodes was performed in all patients, 29 of whom underwent surgical biopsy of the SN after 24 hours. Early images were acquired 5, 15 and 79 min and late images 60-180 min following perilesional injection of 2-4 microdoses of 99mTc-nanocolloid (15-20 MBq). A cobalt marker was used to project the SN on the skin surface which was later stained with indelible ink. For intraoperative localization we used a portable probe and perilesional injection of patent blue violet dye, which proved positive in 24/29 patients (83%). After surgery histological examination of the sentinel lymph nodes (SNs) (hematoxylin-eosin and immunohistochemistry) found positivity for metastatic cells in 6 patients. They all underwent elective lymph node dissection (ELND); five are N0+ and are currently undergoing supportive therapy with interferon alpha with an 8-24-month follow-up, while one N+ patient died 14 months after surgery. Follow-up (3-26 months) of N0- patients has not evidenced any locoregional recurrence so far. Only one case showed hematogenic metastases. This procedure might radically change the therapeutic approach to CS1 melanoma because it is simple, scarcely invasive, and shows a favorable cost-benefit ratio.

One laparoscopic puncture for treatment of ovarian cysts with adnexal torsion in early pregnancy. A report of two cases.

In two cases a simple laparoscopic technique was used to treat ovarian cysts with adnexal torsion in early pregnancy. A single laparoscopic route was sufficient. This procedure has great value for girls and young women for whom the preservation of fertility is a major concern.

[Hepato-cholescintigraphy using technetium Tc 99m diethyl IDA in the follow-up of biliodigestive anastomoses]. / L'epato-colescintigrafia con 99m Tc-dietil-IDA nel follow-up delle anastomosi bilio-digestive.

The results of a study conducted on 24 patients given biliodigestive shunts are reported. Follow-up involved cholescintigraphy using 99m-IDA technetium. This examination provided valuable information about the morphodynamics of biliary flow and when the biliary peak and intestinal appearance times were lengthened, it was also able to identify significant obstructions. The technique is considered highly significant.

SPECT perfusion imaging with 123I-HIPDM in a patient with pulmonary embolism.

The use of 123I-N,N,N'trimethyl-N'-2-hydroxy-3-methyl-5-iodobenzyl-1,3-propanediami ne (123I-HIPDM) as a lung perfusion tracer in a patient with pulmonary embolism is shown. 123I-HIPDM is compared with 99mTc-labeled human albumin microspheres (HAM) using both planar and tomographic (SPECT) imaging. Pulmonary segmental defects are shown by 123I-HIPDM as well as by HAM, with a slightly better definition of perfused areas. Tomograms better show segmental shape of perfusion defects. 123I-HIPDM may be proposed as lung perfusion tracer for both clinical and experimental purposes.

Computerized angioscintigraphy and ultrasound imaging in the management of renal transplants.

The effectiveness of Computerized Renal Angioscintigraphy with 99m-Tc-DTPA and Ultrasound in the differential diagnosis of complications after kidney transplant was evaluated. 13 patients were studied; 6 with a normal graft, 2 with acute tubular necrosis and 5 with an acute rejection episode. Technectium scan and ultrasound diagnosis were in good agreement with clinical assessment resulting in 1.00 and 0.92 sensitivity respectively. The most valuable features of radionuclide and ultrasound techniques are: noninvasiveness, simplicity, rapidity and reproducibility. The selection of a course of treatment could be usefully helped or supported by data obtained from scintigraphy and ultrasound.

Peripheral metabolism of thyroid hormones in man. I. Direct measurement of the conversion rate of thyroxine to 3,5,3'-triiodothyronine (T3) and determination of the peripheral and thyroidal production of T3.

We describe here a new method for the direct measurement of the conversion rate of T4 to T3 in man. The metabolic study was performed in 23 subjects: 13 healthy controls, 7 T4-treated hypothyroids, and 3 sick euthyroid patients. The experimental protocol involved the simultaneous iv bolus injection of [125I]T4 and [131I]T3, and the use of Sephadex G-25 column chromatography to determine the plasma concentrations of [125I]T4, [131I]T3, and [125I]T3 newly formed through 5'-monodeiodination of labeled T4 in the peripheral tissues. The T4 and T3 kinetic parameters were determined by noncompartmental analysis. The conversion rate of T4 to T3 was computed by a method based on the precursor-product relationship, using the [131I]T3 disappearance curve for correcting the concentrations of newly formed [125I]T3 (convolution method). The conversion rate of T4 to T3 was 0.2541 +/- 0.0125 (mean +/- SEM) in the control group and was significantly reduced (0.1283 +/- 0.0204; P less than 0.001) in the sick euthyroid patients, while it was slightly, though not significantly, increased in the T4-treated patients (0.2932 +/- 0.0220). A close agreement was found between the values for the conversion rate obtained by the convolution approach and those derived from the ratio between the serum concentrations of [125I]T3 and [125I]T4 at equilibrium. The conversion rates obtained by the convolution approach were also in good agreement with the values estimated from the molar ratio between the turnover rates of T3 and T4. In the control group, 72.0 +/- 3.6% of the circulating T3 was produced by 5'-monodeiodination of T4 in the peripheral tissues, and 28.0 +/- 3.6% of the circulating T3 derived from direct thyroidal secretion. The sick euthyroid patients showed a significantly smaller proportion of circulating T3 deriving from peripheral conversion of T4 (52.5 +/- 3.9%; P less than 0.025).