A piperidinyl nitroxide stable free radical derivative, TES, was tested as an NMR contrast enhancer of renal structures in normal animals and animals with experimentally induced unilateral renal ischemia, renal vascular congestion, and hydronephrosis. Physiologic measurements indicated that TES is rapidly excreted in the urine with a clearance rate equal to the glomerular filtration rate. Because the compound is strongly paramagnetic, it increases the observable NMR intensity within the kidneys and urine in relatively low doses (0.04 to 0.9 g/kg). TES-enhanced spin echo renal images clearly demonstrated the presence of disease and functional abnormalities in diseased kidneys. These abnormalities were either not evident or only indirectly suggested on nonenhanced NMR images.

Results of computed tomography (CT), scintigraphy, excretory urography, and other imaging tests used to diagnose and stage 38 cases of neuroblastoma prior to treatment were reviewed. Findings of these examinations were correlated with clinical data, laboratory data, results of biopsy, and surgical findings. CT was the most sensitive single test (100%) for the detection and delineation of the primary tumor. Calcifications that suggested the histologic diagnosis of neuroblastoma were present in 79% of the cases. Rim calcifications, the most specific pattern for neuroblastoma, were identified in 29% of all cases. CT alone accurately staged 82% of cases; when complemented by bone marrow biopsy, staging accuracy was 97%. CT alone was more accurate than any combination of imaging tests that excluded CT. An algorithm using CT is presented for the diagnosis and staging of neuroblastoma at reduced cost and with increased efficiency.

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Nuclear magnetic resonance (NMR) images obtained after unilateral ligation of the ureter, renal artery, or renal vein in the rat were analyzed and compared with NMR images of the normal rat kidney. Anatomic and functional correlation of the induced renal lesions was made by concurrent CT and by gross examination of the excised kidneys. Many normal anatomic structures at the level of the renal hilum can be identified by high resolution NMR imaging. Differentiation of urine from renal parenchyma permits detection of gross changes both in renal function and in the mass of the renal parenchyma. NMR imaging is capable of diagnosing hydronephrosis, acute renal ischemia, and acute venous congestion in this rat model. In addition, a trend toward prolongation of the relaxation times T1 and T2 for abnormal renal parenchyma is demonstrated.