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Is “black geode” sign a characteristic MRI finding for extracranial schwannomas?
Author(s) -
Kato Hiroki,
Kanematsu Masayuki,
Ohno Takatoshi,
Nishimoto Yutaka,
Oshima Koji,
Hirose Yoshinobu,
Nishibori Hironori
Publication year - 2013
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.23867
Subject(s) - magnetic resonance imaging , gadolinium , sign (mathematics) , nuclear medicine , medicine , nuclear magnetic resonance , anatomy , radiology , materials science , physics , mathematics , mathematical analysis , metallurgy
Purpose: To evaluate whether the “black geode” sign is a characteristic magnetic resonance imaging (MRI) finding for extracranial schwannomas. Materials and Methods: Forty‐three patients with pathologically confirmed extracranial schwannomas underwent preoperative gadolinium‐enhanced MRI. The black geode sign was defined as the appearance of enhanced outer and inner rings. MR images were retrospectively reviewed for size, configuration, and signal intensity of the lesions in addition to the presence of the black geode sign. Results: Gadolinium‐enhanced T1‐weighted images revealed the black geode sign in seven of 43 patients (16%). The thickness of inner rings (mean 0.6 cm, range 0.3–0.8 cm) was significantly greater than that of outer rings (mean 0.2 cm, range 0.1–0.3 cm) ( P < 0.01). While outer rings were circular or elliptical in shape with smooth contours, inner rings had a lobular configuration with irregular thickness and contours. The degrees of enhancement were significantly stronger with inner rings than with outer rings ( P < 0.01). In histopathological correlation of five patients who underwent total excision, inner and outer rings corresponded to peridegenerative areas and fibrous capsules, respectively. Conclusion: The black geode sign may be fairly specific to extracranial schwannomas on gadolinium‐enhanced MR images. J. Magn. Reson. Imaging 2013;37:830–835. © 2012 Wiley Periodicals, Inc.