In order to provide a detailed description of the MR appearance of intracranial ependymoma, the MR examinations of 12 patients (10 with ependymomas and two with subependymomas) were reviewed and correlated with operative and pathologic reports. Three of 10 ependymomas were intraventricular, two were intraparenchymal, and five were transependymal, extending from CSF spaces into parenchyma. Both subependymomas were intraventricular. Solid ependymomas and subependymomas were iso-to hypointense relative to normal white matter on T1-weighted images and hyperintense on proton-density-and T2-weighted images. Foci of signal heterogeneity within solid neoplasms represented methemoglobin, hemosiderin, necrosis, calcification, and encased native vessels or tumor vascularity. Gd-DTPA-enhanced images in two patients differentiated enhancing tumor from surrounding nonenhancing edema and from surrounding normal brain parenchyma. Cystic neoplasms had sharply defined, round or oval margins and uniform signal intensity equivalent to or slightly hyperintense relative to CSF. Tumor-associated calcification was not demonstrated readily by MR. Sagittal and coronal images were valuable in assessing the amount of intraventricular tumor and route of extension.We conclude that the MR differentiation of ependymomas and subependymomas from other gliomas is provided most reliably by the location and morphology of the tumor and not by differences in signal intensity. The typical ependymoma arises within the fourth ventricle as a solid mass with heterogeneous signal intensity. A propensity for spread is seen along the CSF pathways via the foramina of Magendie and Luschka and the aqueduct of Sylvius. Supratentorial ependymomas may be periventricular in location and have cystic components. The two subependymomas in our series were solid, intraventricular tumors with relatively homogeneous signal intensities.AJNR 11:83-91 , January/February 1990; AJR 154: April1990The appearance of intracranial ependymoma and subependymoma, although well characterized on CT [1-3] , ha? not been described in detail on MR . To our knowledge, the MR findings of ependymoma have been reported in only a few cases, as part of larger series of intracranial neoplasms [4][5][6][7][8] ; there is only one prior report on the MR manifestations of subependymoma [9].We correlated the MR findings with operative and pathologic reports in 10 patients with proved intracranial ependymomas and two patients with subependymomas. The appearance of ependymoma at low (0.35 T) and high (1.5 T) field strengths is described. Materials and MethodsWe reviewed 14 MR studies of 1 0 patients with intracranial ependymomas and two patients with subependymomas. The operative and pathologic reports and hospital and outpatient records were available for all but two patients ; these clinical data were correlated with the MR findings . The patients ranged in age from 1.2 to 59 .0 years (mean, 23.6 years). There were six females and six males. MR examinations performed at initial presentation were

A 78-year-old male presented for evaluation of a cold, painful left foot. He had undergone two recent hospital admissions for unexplained fever, fatigue, arthralgias, and an 8-to 10-lb. weight loss over a 4-month period. The patient had a past medical history of hypertension, hyperlipidemia, benign colon polyps, type II mixed cryoglobulinemia, and a bioprosthetic aortic valve that was placed 2 years earlier. Despite extensive evaluations during these two admissions, including three transesophageal echocardiograms that demonstrated a normally functioning aortic bioprosthesis, no diagnosis was established. Type II mixed cryoglobulinemia was documented and treated with oral steroids and brief plasmapheresis.During the present admission, an acute arterial embolus was diagnosed, and an emergent femoral-popliteal embolectomy was performed. A foul-smelling clot was extracted and sent to the microbiology laboratory for testing. An intraoperative transesophageal echocardiogram showed a mobile vegetation on the bioprosthetic valve and ϩ4 tricuspid regurgitation. Six days later, the patient underwent uneventful aortic valve replacement and tricuspid valve repair. Gram stains of the embolus and valve vegetation were both negative. Fungi-Fluor fungal smears of the same specimens showed many yeasts and hyphae. Routine blood cultures remained negative. No fungal blood cultures were performed.

with the injured joint, or joints, immersed in a suitable bath with a positive electrode unit so that a current of 2-3 milliamperes could be passed. The results were most satisfactory, the treated group returning considerably earlier to full duty than the remainder. Unfortunately this suggestive trial experiment roused no interest or further test or follow-up. All this not 50 years ago but nearer half that. With all the incredible advances in the use of electricity on other fronts in the last 25 years why then in medicine alone has there been not only no advance but retrogression? What is needed is a determined and properly sponsored attack on these claims, routing out and condemning the specious while proving to the satisfaction of the profession the value and field of use of those that survive.-I am, etc., C. B. HEALD Chipping Camden, Gloucestershire Lumbar Disc Problems SIR,-I feel that Mr. A. H. G. Murley (26 August, p. 529) has been unfairly criticized for drawing attention to a common misconception that all leg pain accompanying

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