The polarized single-crystal reflection spectra of Magnus' green salt and two of its tetra-alkylamine analogs have been determined and the corresponding absorption spectra obtained through Kramers—Krönig analyses. It is found that a strong ultraviolet transition exists with the proper polarization for the visible out-of-plane bands to gain their intensity from it through vibronic mixing of zero-order electronic wavefunctions. The correlation of the visible intensity with the nature of the ultraviolet band further confirms this mechanism. Possible assignments of the ultraviolet band are discussed.
Thirty-one adult patients underwent magnetic resonance (MR) imaging after CT scans had demonstrated findings consistent with renal cell carcinoma. MR images were interpreted prospectively and independently of the CT findings. Because the CT scanning was performed at multiple institutions by many examiners, this study was not a direct comparison of CT versus MR. The preoperative diagnoses and staging of the neoplasms, as judged by MR, were compared with those obtained at laparotomy (n = 28), autopsy (n = 1), or biopsy (n = 2). Correct preoperative diagnoses were rendered in 31 patients (100%) on the basis of MR findings. The anatomic staging of 27 renal cell carcinomas was correctly performed by MR in 26 patients (86%). When compared with results of previous studies of the value of CT in the diagnosis and staging of renal neoplasms, MR appears to have several advantages in determination of the origin of the mass; the evaluation of vascular patency; the detection of perihilar lymph node metastases; and the evaluation of direct tumor invasion of adjacent organs. MR is sensitive in determining the extent of tumor thrombus and in evaluating invasion of the inferior vena caval wall. MR should assume an important role in the diagnosis and staging of renal neoplasms.
Review of 22 cases of meningioma indicates that this lesion occurs slightly more frequently on the left but without predilection for sex or age of the patient. The presenting symptoms were nonspecific. Plain radiographs of the skull sometimes demonstrated calcification in the tumor, but more often did not. Cerebral angiography frequently showed enlargement and displacement of the anterior choroidal artery on the side of the tumor; the lateral posterior choroidal artery on the side of the tumor was also enlarged and displaced in seven of nine patients who underwent vertebral arteriography. Pneumoencephalography accurately demonstrated the site and size of the lesion, as did radionuclide scanning if the lesion was vascular. Computerized tomographic (TC) scanning also determined the location and size of the tumors, as well as their mass effect and vascularity; CT scanning also demonstrated calcification that was not visible on the plain skull radiographs in two of six patients who underwent CT scanning and had calcification.
Magnetic resonance (MR) imaging was performed in two groups of patients to determine its usefulness in evaluating fluid-containing renal masses deemed complex with computed tomography (CT). Twenty-two patients in group 1 had indeterminate renal masses by CT, five of which were also indeterminate by ultrasound (US). The results in this group were compared with histologic findings. Group 2 consisted of 20 patients with simple renal cysts diagnosed according to rigid CT criteria. On MR imaging, 11 of the 23 masses in group 1 and 19 of the 20 in group 2 were diagnosed as benign cysts. Fluid within the cyst had long T1 and T2, resulting in a low signal intensity on T1-weighted images. In the 12 remaining lesions in group 1 and in one lesion in group 2, the fluid content was indeterminate and MR did not permit differentiation of cystic renal carcinoma from old hemorrhage or adenoma. When fluid within the cystic mass did not have the MR characteristics of simple fluid, MR was not helpful in characterizing the mass, but when the fluid intensity was similar to normal urine, the cyst was benign.
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