BACKGROUND: Multilocular cystic renal cell carcinomas (MCRCCs) are a recently described variety of renal cell carcinoma with characteristic pathological and clinical features. We found that the radiologic appearances of MCRCCs of smaller size did not fulfill the previously documented criteria of the MCRCCs. This study was conducted to analyze the radiologic characteristics of MCRCCs of smaller sizes. METHODS: The radiologic findings of 13 multilocular cystic renal cell carcinomas of diameter ranging from 10-32 mm (average 22 mm) seen in nine patients were analyzed in correlation with pathologic findings. RESULTS: On US, the tumors were predominantly hyperechoic (11 of 13 tumors) with or without small anechoic areas. Precontrast CT showed the lesions to be either hypodense or hyperdense depending on the presence of hemorrhage. Degree of contrast enhancement was usually slight. The mean increase in CT attenuation was 28 +/- 19 (mean +/- standard deviation) at dynamic phase and 12 +/- 10 at delayed phase. On MR imaging, signal intensities of the tumors were high both on T1- and T2-weighted images (7 of 9 tumors) due to proteinaceous fluid or hemorrhage. Dynamic enhanced MR imaging revealed irregular contrast enhancement within the tumor (5 of 6 tumors). Angiography failed to reveal neovascularity. CONCLUSION: Although multiple cysts were seen within the tumors pathologically, MCRCCs of smaller sizes appeared solid on radiologic examinations. However, contrast enhancement or neovascularity was very slight.

Adult↗

PubMedDate not supplied

Germ cell tumors of the central nervous system originating from non-pineal regions: CT and MR features.

CT and MR findings were retrospectively reviewed in 12 patients with germ cell tumors originating from the non-pineal regions. Cystic or necrotic components were seen in 6 patients. Of 4 germinomas, 2 showed mixed density on the CT. The MR signal intensity of the tumor was non-specific. Of 8 germinomas, 4 were inhomogeneously enhanced on postcontrast CT and T1-weighted MR images. CT and MR features of germinomas originating from non-pineal regions frequently differ from those of germinomas originating from the pineal region. The mass of the tumor often appeared cystic and inhomogeneously enhanced following contrast infusion.

Adolescent↗

PubMedDate not supplied

Preliminary results with technetium-99m MIBI SPECT imaging in patients with brain tumors: correlation with histological and neuroradiological diagnoses and therapeutic response.

SPECT using Tc-99m MIBI was performed in patients with brain tumors in order to determine Tc-99m MIBI uptake in brain tumors and to evaluate the efficacy of MIBI imaging in the assessment of treatment response. A MIBI uptake index was calculated on SPECT imaging. All tumors with a MIBI-index higher than 7.5 were malignant. In the tumors evaluated before and after radiochemotherapy, the MIBI-index immediately following therapy correlated with treatment response 2 months after therapy. Thus, semiquantitative assessment using Tc-99m MIBI SPECT imaging may be useful in the evaluation of treatment response.

Adolescent↗

PubMedDate not supplied

Comparison of MR imaging and CT in discriminating tumor infiltration of bone and bone marrow in the skull base.

We compared MR imaging with CT in revealing tumor infiltration of bone and bone marrow in the skull base of 54 patients. MR imaging had no advantages over when tumor involved the anterior compartment. However, precontrast T1-weighted MR images were more efficient than CT in 37.5% of tumors involving the middle compartment and in 54.5% of tumors involving the posterior compartment, respectively. Precontrast T1-weighted images were more accurate than other pulse sequences in revealing bone and bone marrow that were replaced by tumors.

Adenoma↗

PubMedDate not supplied

Comparison of thallium-201 and gallium-67 imaging in evaluation of head and neck tumors.

PURPOSE: 201Tl imaging was compared with 67Ga imaging in the detection of malignant head and neck tumors. METHOD: Eighteen patients with tumors in the head and neck region underwent both planar and SPECT imaging using 201Tl-chloride and 67Ga-citrate. The detection of primary tumors and lymph node (LN) metastases by visual evaluation was compared between 201Tl and 67Ga imaging. Additionally, quantitative analysis of the SPECT images was performed in eight patients. RESULTS: On visual evaluation, primary tumor uptake was detectable in 100% on the 201Tl SPECT images compared with 44% on the 67Ga SPECT images. The sensitivity, specificity, and accuracy of 201Tl in detecting LN metastases were higher than those of 67Ga SPECT; however, there was no statistical difference between 201Tl and 67Ga. The tumor-to-background ratio was significantly higher on 201Tl SPECT than on 67Ga SPECT. CONCLUSION: This study suggested that 201Tl could be useful in the evaluation of malignant tumors in the head and neck region.

Aged↗

PubMedDate not supplied

Artificial embolization of the middle cerebral artery in primates. Description of an experimental model with extracranial technique.

Artificial embolization of the middle cerebral artery (MCA) was produced in the primate, with a technique similar to that described by Luessenhop and Spence (1960) for the treatment of an inoperable arteriovenous malformation in the territory of the MCA. Silicone spheres (1 to 1.5 mm in diameter) were introduced into the internal carotid artery (ICA) via the external carotid artery (ECA). Emboli (1 to 1.3 mm) passed into the anterior cerebral artery (ACA) in 12%, and into the MCA in 50%. Emboli (1.2 to 1.5 mm) stopped at the ICA bifurcation in 54%. In all primates (82.35%1 in which the emboli occluded the ICA bifurcation or the MCA, immediate contralateral hemiplegia developed. The correlation of the anatomical characteristics of the intracranial vasculature of the ICA bifurcation, the diameter of the emboli, and the anatomical localization of the silicone spheres suggests that this experimental model can produce a selective acute "point" occlusion of the MCA in at least 75% of the cases without violating the cranium, in which the resultant changes in the distribution of water and electrolytes in the brain during the acute ischemic event in the territory of the MCA of the primate can be studied.

Animals↗

PubMedDate not supplied

Experimental regional cerebral ischemia in the middle cerebral artery territory in primates. Part 1: Angio-anatomy and description of an experimental model with selective embolization of the internal carotid artery bifurcation.

Selective embolization of the internal carotid artery bifurcation (ICA bifurcation) was performed in monkeys (Macaca mulatta) to study acute regional cerebral ischemia in the middle cerebral artery (MCA) territory with minimum surgical intervention in the neck under sedated conditions. The anthropomorphic similarity in angio-anatomy of the carotid system of monkeys and the use of silastic spheres, as artificial emboli, of the critical diameter of 1.2 to 1.4 mm resulted in the overall success rate of 87% in localizing the site of embolization to the ICA bifurcation, producing ischemia in the whole middle cerebral artery territory. All the animals with ICA-bifurcation embolization had contralateral deep motor weakness and conjugate eye deviation with nystagmus toward the site of embolization. Simultaneous EEG recording showed flattening of the basic background activities over the affected MCA area and cerebral arteriograms showed definite retrograde filling of the proximally occluded MCA. Clinical recovery was observed in a few animals within two to five hours of embolization. Gross ischemic swelling in the affected MCA territory, particularly in the gray matter, became obvious in six of eight animals which were exposed to four to five hours of ischemia. The angio-anatomical study of the carotid system of this experimental animal as a background for this MCA stroke model confirmed the previous observations of other investigators that the extremely abundant leptomeningeal anastomoses would be one of the major factors leading to the variability in the clinicopathological pictures seen in the models of proximal MCA occlusion. In addition, the pre-parenchymal anastomoses in the base of brain between the medial striate arteries from the proximal anterior cerebral (ACA) and lateral lenticulostriate arteries from the MCA were observed and described as a possible functional collateral to the basal ganglia in case of proximal MCA occlusion.

Animals↗