title: Loculated intracranial leptomeningeal metastases: CT and MR characteristics.
abstract: Studies of twenty-five patients with loculated leptomeningeal tumor metastases diagnosed by CT and/or MR were analyzed retrospectively. Medulloblastoma was the most frequent primary tumor (8/25, 32%). Four subgroups of loculated patterns were identified. Type A included mass(es) limited to the subarachnoid space without obvious direct parenchymal infiltration; this pattern occurred in 12 patients, of whom five had associated diffuse pattern. Type B was characterized by mass(es) still predominantly in the subarachnoid space but with minor transpinal parenchymal infiltration; this pattern was found in five patients. Type C comprised subarachnoid mass(es) with marked transpinal extension mimicking parenchymal lesion; this pattern was observed in three patients. Type D consisted of subarachnoid mass(es) growing along the perineural CSF space; this pattern was noted in two patients. Additionally, two patients presented with combined A and C patterns, and one patient had a combined B and C pattern. More than half the patients (14/25, 56%) presented with a single lesion. The most frequent locations were the suprasellar cistern, ventricular walls, and lateral recesses of the fourth ventricle, Gd-DTPA-enhanced T1-weighted MR images appeared best for demonstrating the site and extent of disease. Recognition of the loculated patterns of leptomeningeal metastases, which are less common than the diffuse pattern, is important to radiologists and clinicians for correct diagnosis and proper management of patients with this disease.
authors.affiliation: Department of Diagnostic Radiology, University of Texas M.D. Anderson Cancer Center, Houston 77030.
authors.forename: Y Y
authors.initials: YY
authors.lastname: Lee
authors.forename: R D
authors.initials: RD
authors.lastname: Tien
authors.forename: J M
authors.initials: JM
authors.lastname: Bruner
authors.forename: C A
authors.initials: CA
authors.lastname: De Pena
authors.forename: P
authors.initials: P
authors.lastname: Van Tassel
mesh_terms: D001099:Arachnoid / Q000000981:diagnostic imaging / Q000473:pathology; D003287:Contrast Media; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging; D008577:Meningeal Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000556:secondary*; D009942:Organometallic Compounds; D004369:Pentetic Acid; D010841:Pia Mater / Q000000981:diagnostic imaging / Q000473:pathology; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D004369:Pentetic Acid; D019786:Gadolinium DTPA