RadioGraphics の無料総説は教育的である

RadioGraphics の無料総説は教育的である。また、病理との対比もなされている。神経内科医が知っておくべき総説をときどき紹介する。専門医試験にも役立つと思われる。

                       

Patterns of Contrast Enhancement in the Brain and Meninges

RadioGraphics, 27, 525-551, 2007.

http://radiographics.rsna.org/content/27/2/525.full

Abstract

Contrast material enhancement for cross-sectional imaging has been used since the mid 1970s for computed tomography and the mid 1980s for magnetic resonance imaging. Knowledge of the patterns and mechanisms of contrast enhancement facilitate radiologic differential diagnosis. Brain and spinal cord enhancement is related to both intravascular and extravascular contrast material. Extraaxial enhancing lesions include primary neoplasms (meningioma), granulomatous disease (sarcoid), and metastases (which often manifest as mass lesions). Linear pachymeningeal (dura-arachnoid) enhancement occurs after surgery and with spontaneous intracranial hypotension. Leptomeningeal (pia-arachnoid) enhancement is present in meningitis and meningoencephalitis. Superficial gyral enhancement is seen after reperfusion in cerebral ischemia, during the healing phase of cerebral infarction, and with encephalitis. Nodular subcortical lesions are typical for hematogenous dissemination and may be neoplastic (metastases) or infectious (septic emboli). Deeper lesions may form rings or affect the ventricular margins. Ring enhancement that is smooth and thin is typical of an organizing abscess, whereas thick irregular rings suggest a necrotic neoplasm. Some low-grade neoplasms are “fluid-secreting,” and they may form heterogeneously enhancing lesions with an incomplete ring sign as well as the classic “cyst-with-nodule” morphology. Demyelinating lesions, including both classic multiple sclerosis and tumefactive demyelination, may also create an open ring or incomplete ring sign. Thick and irregular periventricular enhancement is typical for primary central nervous system lymphoma. Thin enhancement of the ventricular margin occurs with infectious ependymitis. Understanding the classic patterns of lesion enhancement—and the radiologic-pathologic mechanisms that produce them—can improve image assessment and differential diagnosis.

LEARNING OBJECTIVES FOR TEST 6

After reading this article and taking the test, the reader will be able to:

・Define contrast enhancement as it applies to CT and MR imaging of the brain and meninges.

・Explain the role of the blood-brain barrier and vascularity in contrast enhancement in the central nervous system.

・Use the patterns of enhancement to distinguish different pathologic processes in the brain and meninges.

http://blog.with2.net/link.php/36571

(ブログランキングに登録していますのでよろしく)

marugametorao について

神経内科専門医 neurologist
カテゴリー: 神経内科医, 神経学, 医学, 医学教育, 挑戦 パーマリンク

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