MRI Findings of Central Nervous System Granulocytic Sarcoma (Chloroma)

PURPOSE: To characterize MRI findings of central nervous system(CNS) granulocytic sarcoma (chloroma) and to analyse the points which differentiate it from other CNS tumors. MATERIALS AND METHODS: We evaluated MRI in six patients with CNS granulocytic sarcoma proven by surgery or bone marrow biopsy (intracranical, one case and spine five cases). A 0.5T superconductive MR machine was used for diagnosis and, axial, coronal and sagittal T1- and T2-weighted spin echo images and Gd-DTPA enhanced T1-weighted images were obtained. We retrospectively analized the location, signal intensity, margin, contrast enhancement and homogeneity, and bony change around the tumor. RESULTS: MRI findings of CNS granulocytic sarcomas were as follows : one tumor was seen to be an extra-axial mass in the posterior fossa of the brain, four were epidural, and one was an epidural and presacral masses in the spine ; tumor magins were lobulated and three were smooth. On T1-weighted images, all tumors were of isoignal intensity; on T2-weighted images, four were of isosignal intersity and two were of high signal intensity. Contrast enhancement was inhomogeneous in five of six cases. Bony change around the tumor was seen in two cases. CONCLUSION: On T1-weighted images, CNS granulocytic sarcomas (chloromas) were of isosignal intensity, relative to brain parenchyma or spinal cord ; on T2-weighted images, they were of iso or high signal intensity, with relative contrast enhancement. These points could be useful in differentiating them from other CNS tumors.

CT and MRI Findings of Intraventricular Neurocytoma

PURPOSE: Intraventricular neurocytoma, a recently recognized benign primary cerebral tumor of young adults, can be confused with oligodendroglioma and other neoplasms. The purpose of this paper is to describe the characteristic CT and MR imaging findings of intraventricular neurocytoma. MATERIALS AND METHODS: CT and MR imaging findings of five patients (M:F=2:3, ages 17-64, mean age 41) with intraventricular neurocytoma were retrospectively reviewed. All patients underwent CT scan and cerebral angiography. In four patients, MR imaging was performed and axial, sagittal, and coronal T1- and T2-weighted spin echo and gadolinium enhanced images were obtained. We evaluated the tumors with regard to location, size, shape, CT density, MR intensity, enhancement pattern, and internal texture such as calcification and cystic changes. RESULTS: All tumors were located in the lateral ventricles; especially around the foramen of monro (four cases). Their size varied from 1.0 x 1.5 cm to 4.0 x 3.0 cm and all showed a lobulated appearance. On precontrast CT scan, all tumors showed heterogeneous density due to multiple intratumoral calcifications and cystic changes. MR imaging showed a heterogeneous signal with iso- or slight hyperintensity on T1-weighted and hyperintensity on T2-weighted image, relative to cerebral parenchyme. After contrast injection, varying degrees of enhancement were noted on both CT and MR images. CONCLUSION: An intraventricular mass with or without calcification and cystic changes in the anterior portion of the lateral ventricle is suggestive of intraventricular neurocytoma. MR imaging is better in defining the exact location and cystic changes of the tumor, whereas CT is better for the characterization of calcifications.

Contrast Enhancement Patterns of Hepatic Masses using Three Phase Spiral CT

PURPOSE: To compare the contrast enhancement patterns of hepatocellular carcinomas(HCCs), hemangiomas, and metastases on three-phase images with spiral CT for differential diagnosis. MATERIALS AND METHODS: Three-phasespiral CT scan was performed in 73 patients with hepatic masses. CT scanning was performed with a table speed of 10mm/sec, section thickness of 10mm, and a reconstruction interval of 5mm, 100-150ml of contrast medium was injected intravenously with an automatic injector at a rate of 2-3mL/sec. CT scans were obtained at 30, 70 and 180 seconds after the start of contrast material injection. RESULTS: The enhancement patterns of 136 lesions in 53 patients with HCCs were as follows : 47 lesions(35%) were totally high and 55(40%) were mixed in the early phase ;30 lesions(22%) were mixed and 66(49%) were totally low in the portal phase ; and 105 lesions(78%) were totally low in the delayed phase. In hemangiomas of 23 lesions in 15 patients, 7 lesions(30%) were peripherally high and11(48%) were totally low in the arterial phase ; 4 lesions(17%) were totally high and 12(53%) were peripherally high in the portal phase ; 10 lesions(42%) were totally high and 4(18%) were peripherally high in the deayed phase. In metastatic liver mali gnancies of 42 lesions in 5 patients, 13 lesions(31%) were peripherally high and 22(52%) were totally low in the arterial phase ; 32 lesions(77%) were totally low in the portal phase, and 35(83%)were totally low in the delayed phase. CONCLUSION: Three-phase spiral CT scanning is a useful diagnostic methodin the differential diagnosis of hepatic masses including HCCs, hemangiomas, and hepatic metastases.