RT Journal Article
SR Electronic
T1 Single-voxel proton MR spectroscopy of nonneoplastic brain lesions suggestive of a neoplasm.
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 1695
OP 1703
VO 19
IS 9
A1 H G Krouwer
A1 T A Kim
A1 S D Rand
A1 R W Prost
A1 V M Haughton
A1 K C Ho
A1 S S Jaradeh
A1 G A Meyer
A1 K A Blindauer
A1 J F Cusick
A1 G L Morris
A1 P R Walsh
YR 1998
UL http://www.ajnr.org/content/19/9/1695.abstract
AB BACKGROUND AND PURPOSE MR spectroscopy is used to characterize biochemical components of normal and abnormal brain tissue. We sought to evaluate common histologic findings in a diverse group of nonneoplastic diseases in patients with in vivo MR spectroscopic profiles suggestive of a CNS neoplasm.METHODS During a 2-year period, 241 patients with suspected neoplastic CNS lesions detected on MR images were studied with MR spectroscopy. Of these, five patients with a nonneoplastic diagnosis were identified retrospectively; a sixth patient without tissue diagnosis was added. MR spectroscopic findings consistent with a neoplasm included elevated choline and decreased N-acetylaspartate and creatine, with or without detectable mobile lipid and lactate peaks.RESULTS The histologic specimens in all five patients for whom tissue diagnoses were available showed significant WBC infiltrates, with both interstitial and perivascular accumulations of lymphocytes, macrophages, histiocytes, and (in one case) plasma cells. Reactive astrogliosis was also prominent in most tissue samples. This cellular immune response was an integral component of the underlying disorder in these patients, including fulminant demyelination in two patients, human herpesvirus 6 encephalitis in one patient, organizing hematoma from a small arteriovenous malformation in one patient, and inflammatory pseudotumor in one patient. Although no histologic data were available in the sixth patient, neoplasm was considered unlikely on the basis of ongoing clinical and neuroradiologic improvement without specific therapy.CONCLUSION Nonneoplastic disease processes in the CNS may elicit a reactive proliferation of cellular elements of the immune system and of glial tissue that is associated with MR spectroscopic profiles indistinguishable from CNS neoplasms with current in vivo MR spectroscopic techniques. Such false-positive findings substantiate the need for histologic examination of tissue as the standard of reference for the diagnosis of intracranial mass lesions.