Choroidal melanomas: correlation of NMR spectroscopy and MR imaging

Six freshly enucleated, unfixed human eyes with choroidal melanomas were imaged on a 1.4-T superconducting magnetic resonance (MR) imaging system. Immediately thereafter the eyes were sectioned, and tumor samples were removed for study on a variable-field (0.19-1.4 T) nuclear MR spectroscopy unit. Shorter T1 and T2 relaxation times were observed in those tumors with the greater concentrations of melanin. This is believed to result from the paramagnetic effect of radicals known to exist in melanin. High magnetic field MR imaging can enable one to distinguish between pigmented melanomas; proteinaceous effusions; fresh and subacute hematomas; and nonmelanotic tumors, including amelanotic melanomas; but may not enable melanotic melanoma to be distinguished from fat or amelanotic melanoma from other nonpigmented tumors.     

Spinal cord central echo complex: histoanatomic correlation

Real-time sonography consistently demonstrates an echo complex centrally located in the spinal cord. This echogenic focus is currently attributed to the central canal. The authors sought the source of this central echo with ultrasound (US) and histoanatomic study of both fresh and fixed cadaver spinal cords. Correlative transverse sections of the spinal cord were stained with hematoxylin-eosin and Luxol fast blue for cells and myelin and with Holzer stain for glial fibrils. The central echo complex is produced by the interface between the myelinated ventral white commissure and the central end of the anterior median fissure. Variations in the shape of the central complex seem to reflect varying degrees of flaring of the central end of the anterior median fissure. The inconstant residual central canal and islands of residual ependymal cells are clearly not the source of the central echo complex.     

The opacified maxillary sinus: CT findings in chronic sinusitis and malignant tumors

To distinguish opacification owing to inflammatory conditions (sinusitis) from that caused by nasomaxillary malignancy, computed tomography scans in 24 proved cases of sinusitis or tumor were reviewed for features related to sinus size, wall thickness, and character of bone erosion. An anatomic system was defined for classifying lesions according to the surface and type of bony involvement. In 12 cases of chronic maxillary sinusitis, the involved sinus was usually small and thick walled. The nasal surface of the involved sinus usually was eroded; often the orbital surface was eroded. The erosion was, however, short, irregular, and in the region of a normal dehiscence (semilunar hiatus or infraorbital canal) in all cases. The infratemporal surface was never eroded. In 12 cases of nasomaxillary neoplasia, the sinus was enlarged, one or more walls of the involved sinus being thinned and expanded. Bone erosion was present in all cases; erosion of the infratemporal surface was specific for neoplasia and significant as the usual site of recurrence.     

The angiographic diagnosis of acute hemorrhagic renal cortical necrosis

The authors report a case of acute renal failure resulting from acute cortical necrosis. A selective renal angiogram defined a very unusual, abrupt termination of vascularity at the interlobular and arcuate levels. Nephro-angiography is an important tool in the diagnosis of acute cortical necrosis in the initial phase of acute renal failure.