Toshiaki Higa

Evaluation of radionuclide imaging and echography in the diagnosis of thyroid nodules.

Radionuclide imaging with both Tc-99m sodium pertechnetate and TI-201 chloride was studied in 152 patients with thyroid nodules. Ultrasonography also was performed in 81 of those patients. Tc-99m sodium pertechnetate scans demonstrated nodules in 69.7% of 78 differentiated thyroid carcinomas (DC) and 72.2% of 54 thyroid adenomas (Ad). TI-201 chloride was accumulated in 73.7% of DC and 53.6% of Ad. By combining the Tc-99m sodium pertechnetate and TI-201 chloride scans, the detectability of the nodules was increased to 90.8% for DC and 88.9% for Ad, respectively. The Tc-99m sodium pertechnetate scans showed better visualization of cystic lesions than did the TI-201 chloride imaging. The TI-201 chloride images clearly demonstrated intrathoracic tumor invasions in six cases of carcinoma and two cases of Ad. The TI-201 chloride scan was also of value in detecting regional lymph node involvement and the recurrence and metastasis after thyroidectomy. The detectability of space-occupying lesions by ultrasonography was 96.3% in 81 patients with thyroid nodules. Ultrasonography differentiated well between solid and cystic lesions. The presence and extent of nodular lesions were detected with radionuclide imaging and ultrasonography in 98.8% of patients. Radionuclide imaging combined with ultrasonography provides a rapid, convenient, and useful method for the localization and visualization of thyroid tumors.

Krypton-81m single photon emission tomography and the collateral circulation in carotid occlusion: the role of the circle of Willis and leptomeningeal anastomosis

SummaryCerebral perfusion images were investigated in patients with carotid artery occlusion, using single photon emission computed tomography with the infusion of krypton-81m into the internal, common carotid and vertebral arteries. The contribution of the circle of Willis and cerebral cortical anastomoses to the maintenance of adequate blood supply into the involved hemisphere was analysed. It was concluded that the cerebral perfusion image is superior to angiography in evaluating collateral circulation, and in the case of carotid occlusion, the circle of Willis is important in preventing infarction in the territory of the perforating arteries, while the cerebral cortex mainly receives its blood supply through the cortical leptomeningeal anastomoses, illustrating the major role of the leptomeningeal anastomosis as a collateral channel.ZusammenfassungZerebrale Perfusionsbilder wurden bei Patienten mit Halsschlagaderverschluß untersucht. Dazu wurde eine Infusion mit Krypton 81m in die A. carotis comm., A. carotis int. und in die A. vertebralis vorgenommen und dann computergesteuerte Einzelphotonenemissionstomogramme angefertigt. Analysiert wurde, welchen Beitrag der Gefäßkranz an der Hirnbasis und die Anastomosen der Großhirnrinde leisten, um eine angemessene Blutversorgung des betroffenen Gebietes aufrechtzuerhalten. Man kam zu dem Schluß, daß das zerebrale Perfusionsbild in der Abschätzung von Nebenkreisläufen der Angiographie überlegen ist. Im Fall eines Halsschlagaderverschlusses ist der Gefäßkranz an der Hirnbasis von Bedeutung, einen Infarkt im Gebiet der perforierenden Arterien zu verhüten, während die Großhirnrinde vorwiegend über die Anastomosen der weichen Hirnhaut mit Blut versorgt wird, was die Hauptrolle der Anastomosen der weichen Hirnhaut beweist.

SPECT with N-isopropyl-p iodoamphetamine in occlusive cerebrovascular diseases

The role of SPECT imaging with N-isopropyl-p iodoamphetamine (I-123 IMP) in the detection of angiographically documented occlusive cerebrovascular diseases was evaluated in 24 patients, and the results of regional cerebral blood flow (rCBF) were compared with x-ray CT. Twelve patients had internal carotid occlusion, ten had intracranial occlusion beyond the circle of Willis, one had common carotid occlusion, and one had basilar artery occlusion. SPECT images were obtained with a gamma camera, which was rotated 360° around the patients head 30 minutes after an intravenous injection of 3 mCi of I-123 IMP. CT images in the transverse plane were obtained, and the regions of reduced attenuation were identified for comparison of topographic extension of the lesion with the regions of decreased rCBF seen on SPECT. In six cases, the lesions seen on the SPECT images were distinctly more extensive than those seen on CT. In the remaining 18 cases, the extent of the lesion was identical on both CT and SPECT images. Radiochemical and radionuclide impurities, the distance of the detector from the head, and the nature of the collimator affected the SPECT results. I-123 IMP SPECT imaging complements CT findings in detecting the ischemic zones beyond the regions identified on CT images, and may have a major rule in the management of patients with occlusive cerebrovascular diseases.

Superimposition of Krypton-81m single photon emission CT and X-ray CT images for cerebral blood flow evaluation.

Selective arteriographic infusion of krypton-81m was used to obtain cerebral single photon emission computed tomograms. These were then superimposed on X-ray computed tomograms to assess topographically the perfusion of the entire brain. This method enhances the detecting capability for abnormal perfusion areas and has been used in 21 patients with various brain diseases.

A femocerebral catheter for middle-aged patients of relatively small stature

SummaryThe authors describe a catheter for multiartery studies in middle aged patients of relatively small stature. Experience in more than a thousand cases proved its special usefulness in selecting the left common carotid artery with tortuous aortic arch.