Proton MR spectroscopy and diffusion-weighted MR imaging for the diagnosis of intracranial tuberculomas. Report of two cases.

With the current prevalence of tuberculosis, the incidence of intracranial tuberculoma may be on the rise in industrialized nations. However, clinical findings suggestive of systemic tuberculosis are frequently subtle or absent in patients with intracranial tuberculoma, and no specific neuroradiologic characteristics of tuberculoma have been defined as yet. We report two cases of ring-enhanced intracranial tuberculoma in which magnetic resonance (MR) proton spectroscopy and diffusion-weighted (DW) imaging were useful in the differential diagnosis between tuberculoma and other ring-enhanced mass lesions. Pulmonary tuberculosis had been diagnosed in one patient, but radiologic lung study and tuberculin skin test were negative in the other. DW imaging showed bright signal intensity in the core of all lesions in both patients. Malignant gliomas and metastatic brain tumors do not have this characteristic. Proton MR spectroscopy of lesion cores showed lipid peaks and a choline peak in one, and a lipid/lactate mixture pattern in the other, which differed distinctively from those of the pyogenic brain abscess. in each case, one lesion was surgically removed. Antituberculosis drugs were started before surgery for one patient and after surgery for the other. In both, the remaining lesions were reduced significantly in size. We discuss the diagnostic potential of these MR techniques and management options of intracranial tuberculoma.