Role of diffusion weighted imaging in differentiation of intracranial tuberculoma and tuberculous abscess from cysticercus granulomas-a report of more than 100 lesions
Introduction
Intracranial tuberculoma is still the commonest cause of intracranial space occupying lesion in the developing countries. It is also on the rise in industrialized nations with the endemicity of AIDS and increasing use of immunosuppressive agents for the management of organ transplantation [1], [2]. Though CT and conventional MRI features have been described for the diagnosis of tuberculomas and tuberculous abscess, these are not very specific of the disease in a number of patients [2]. Addition of proton MR spectroscopy and magnetization transfer MRI to the brain infection protocol has improved the tissue characterization of tuberculomas and tuberculous abscesses considerably [3], [4], [5], [6], [7], [8]. However, there are a small number of patients where it may not always be possible to differentiate these lesions from degenerating neurocysticercosis (NCC).
Currently, a large number of non-stroke neurological conditions have been investigated with DWI, like tumors, abscess, epidermoids, and encephalitis where a restricted diffusion with low ADC may be noted [9], [10]. Recently, few reports have described diffusion changes in patients with intracranial tuberculoma with variable ADC values [11], [12], [13]. We describe spectrum of diffusion abnormalities in patients with tuberculomas and tuberculous abscess with an aim to further understand the pathology of the disease process and to look for its possible role in assisting the current MR techniques in differentiation of these lesions from degenerating cysticercus granuloma.
Section snippets
Subjects
A total of 30 patients formed the study material for the present study. All these patients presented to us with a varied clinical presentation like fever, signs of meningeal irritation, mass lesion with signs and symptoms localized to its topographic location or seizures. Informed consent was taken from the patients or nearest kin of the patients that were included in this study. There were 13 males and 17 females with age range between 3 and 55 years (mean age 31 years). In 12 patients,
Tuberculous lesions
A total of 70 lesions were evaluated for this study in 30 patients. All these lesions showed rim enhancement on post-contrast T1 weighted MT imaging. ADC from the tuberculous lesions is summarized in Table 1.
Group I (T2 hypointense): There were 42 lesions in this category (Fig. 1). Mean ADC values from the core and wall of the lesion were (1.24 ± 0.32) × 10−3 and (1.06 ± 0.15) × 10−3 mm2/s, respectively. The ADC value from the core of these lesions was significantly higher compared to the wall (p <
Discussion
Diffusion weighted imaging is considered the most sensitive technique for early detection of stroke. Recently, a large number of non-stroke conditions have been described where the restricted diffusion is seen. These include encephalitis, abscess, Creutzfeldt-Jakob disease (CJD), multiple sclerosis and hypercellular tumors like medulloblastoma [9], [10]. In the present study we have observed restricted diffusion in T2 frankly hyperintense and T2 minimally hyperintense tuberculomas with ADC
Acknowledgment
Asht M. Mishra acknowledges the financial assistance from Council of Scientific and Industrial Research, New Delhi, India.
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