MRI findings of intracranial tuberculomas

Clinical Imaging 32 (2008) 88 – 92

MRI findings of intracranial tuberculomas Guner Sonmez a,⁎, Ersin Ozturk a , H. Onur Sildiroglu a , Hakan Mutlu a , Ferhat Cuce a , M. Guney Senol b , Ali Kutlu c , C. Cinar Basekim a , Esref Kizilkaya a a

Department of Radiology, GATA Haydarpasa Teaching Hospital, Istanbul, Turkey Department of Neurology, GATA Haydarpasa Teaching Hospital, Istanbul, Turkey c Department of Chest Disease, GATA Haydarpasa Teaching Hospital, Istanbul, Turkey b

Received 25 April 2007; accepted 20 August 2007

Abstract Purpose: Tuberculosis involvement of the central nervous system continues to represent a serious problem, particularly in developing countries. The aim of this study was to characterize the magnetic resonance imaging (MRI) findings of intracranial tuberculoma, a form of neurotuberculosis. Methods: We retrospectively reviewed the data of 27 patients with intracranial tuberculomas. These consisted of 17 women and 10 men with a mean age of 26 years (14–51). MRI was performed on all patients. Results: A total of 64 tuberculomas were found in these patients, of which 41 were distributed in the cerebral hemispheres, 17 in the cerebellar hemispheres, and 6 in the brainstem. Accompanied meningitis was detected in three patients, hydrocephalus in five patients, and hydrocephalus with meningitis in one patient. Conclusion: MRI makes a significant contribution to diagnosis of intracranial tuberculomas and can objectively determine accompanying abnormalities. © 2008 Elsevier Inc. All rights reserved. Keywords: Intracranial tuberculoma; Neurotuberculosis; Central nervous system; MRI

1. Introduction Tuberculosis (TB) is a disease that can involve all systems, and unless treated, can give rise to serious consequences by damaging the involved system. Involvement of the central nervous system (CNS) is the most dangerous form of TB, which continues to represent an endemic public health problem, particularly in developing countries [1,2]. The disease occurs by spreading secondarily to the CNS years after the initial pulmonary infection with reactivation of the bacillus by the hematogenous route. CNS spread results in two interrelated pathological processes, in the form of TB meningitis or intracranial tuberculomas. The most

⁎ Corresponding author. GATA Haydarpasa Egitim Hastanesi, Uskudar, Istanbul, Turkey. Tel.: +90 216 5184959 (home), +90 216 5422805 (work); fax: +90 216 5422808. E-mail address: [email protected] (G. Sonmez). 0899-7071/08/$ – see front matter © 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.clinimag.2007.08.024

commonly seen form is meningitis, followed by tuberculomas and the much rarer TB abscesses [3]. Our aim in this study was to present the magnetic resonance imaging (MRI) findings of intracranial tuberculomas, which may be confused with space-occupying lesions and may follow a fatal course.

2. Materials and methods Our department's records were reviewed, and patients diagnosed with intracranial tuberculoma at our hospital between 2002 and 2007 were evaluated retrospectively. The study population consisted of 27 patients (17 women and 10 men) with ages ranging from 14 to 51 (mean age, 26). Diagnosis of neurotuberculosis was confirmed by means of typical alterations in the brainstem or with microbiological/ histological tests. Cranial MRI images had been obtained from all patients.

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Fig. 1. One peripheral (white arrow) and nodular (black arrow) contrastenhancing tuberculoma located in deep white matter in the left cerebral hemisphere on contrast-enhanced T1 weighted coronal image. Note the contrast enhancement and thickening of the adjacent meninges.

A 1.5-T scanner (Siemens Magnet Vision, Erlangen, Germany) was used for examination. Conventional T1weighted [640/14 (TR/TE) matrix, 192×256] and T2weighted [3900/99 (TR/TE) 264×512] images were obtained, as well as contrast-enhanced T1-weighted images with MT. The number of lesions, their localizations, dimensions, signal characteristics, and contrast enhancement patterns were all recorded. The lesions were divided into two groups

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Fig. 3. Two ring-like contrast enhancing tuberculomas in the right pontocerebellar angle on T1-weighted axial image.

as tuberculomas including caseating and noncaseating granuloma. Then tuberculomas including caseating granuloma were redivided into two subgroups. 3. Results Sixty-four tuberculomas were detected in these patients, of which 41 (64%) were distributed in the cerebral hemispheres, 17 (26.5%) in the cerebellar hemispheres, and 6 (9.4%) in the brain stem (Figs. 1–3). Tuberculoma dimensions varied between 2 and 4.5 cm. Fifty-eight of the lesions were smaller than 2.5 cm, and six were greater than 2.5 cm. Lesions were classified as caseating or noncaseating granuloma depending on their signal intensities and contrast enhancement characteristics, according to which 55 were caseating and nine noncaseating granulomas (Figs. 4 and 5). Edema and mass effect were observed around only four (6.2%) tuberculomas, with none in the others (Fig. 6) (Table 1). Lesions were solitary in three (11%) patients and multiple in 24 (89%). There was accompanying meningitis in three (11.1%) patients and hydrocephalus in five (18.5%) (Fig. 6) (Table 2). 4. Discussion

Fig. 2. Tuberculoma in the left cerebellar hemisphere (arrow) on contrastenhanced T1-weighted coronal image.

There has been an increase in the incidence of extrapulmonary TB, seen in 20% of all TB cases, in recent years. The effect of extrapulmonary TB on the nervous system is known as neurotuberculosis. This, which constitutes 5% of extrapulmonary TB cases, is observed rarely in

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Fig. 4. Tuberculoma including caseating granulomas. (A) Hypointense tuberculoma in the corpus callosum splenium in T1-weighted axial section and (B) in hyperintense signal in T2-weighted section. Hypointense rim and edema are present around the tuberculoma. (C) Ring-like contrast enhancement on T1weighted sagittal image could be seen. Note the diffuse contrast enhancement of the perimesencephalic cistern.

between 0.2% and 2% of patients with systemic TB [4,5]. Mortality in these dangerous forms is 20% in children younger than 5 years, 60% in patients aged over 50 years, and 80% in clinical cases with a duration longer than 2 months [1]. It has been reported at autopsies carried out in the early 20th century that tuberculomas, a form of CNS involvement, represented 34% of intracranial mass lesions [4]. This level was determined at 0.2% in brain tumor cases on which biopsy was performed in one developing country [4]. The incidence of intracranial tuberculoma varies between 0.15% and 0.18% in developed countries. While generally encountered in developing countries, together with an increase in migration from these countries to developed ones and in HIV infection, the incidence in developed countries is also on the increase [6,7]. Intracranial tuberculoma presents a more difficult clinical picture than meningitis. Clinical diagnosis is more difficult than for other space-occupying lesions. Findings of meningeal irritation and headache usually exhibiting a slow progression and subsequent cranial nerve involvement are followed by neurological deficits and progressive mental alteration in a period of a few weeks. There may be no

findings of systemic infection or laboratory correlation because the bacillus is not always present in brain stem fluid and excised material. For that reason, negative test findings do not exclude the possibility of TB. Intracranial tuberculoma may emerge with meningitis or with no meningeal involvement, and may be seen in the form of solitary or multiple tuberculomas [8]. Multiple tuberculomas are more common [7,9–11]. In our study, lesions were multiple in 89% of cases. Kilani et al. [7] reported a combination of meningitis and tuberculoma at a level of 9.8% in a 122-patient study. This was determined as 11% in our study, which is in agreement with the literature. Ozates et al. reported hydrocephalus in 80% of patients diagnosed with neurotuberculosis in one study. Kilani et al. [7], on the other hand, reported that isolated intracranial tuberculomas were accompanied by hydrocephalus at a level of 11.2%. Hydrocephalus was determined at a level of 18.5% in our study, which is compatible with the findings of Kilani et al. Tuberculomas vary between 2 mm and 6 cm in size. Gupta et al. [12] reported that 88% of lesions were less than 2.5 cm in size. Tuberculomas smaller than 2.5 cm were observed at a level of 90.5% in our study.

Fig. 5. Tuberculoma including noncaseating granuloma. (A) Tuberculoma in the right thalamus is hypointense on T1-weighted axial image and (B) hyperintense on T2-weighted axial image. (C) Note the nodular contrast enhancement of the tuberculoma on T1-weighted coronal image.

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Table 2 Observed abnormalities associated with tuberculoma

Fig. 6. Ring-like contrast enhancement of a tuberculoma in the splenium of the corpus callosum in contrast-enhanced T1-weighted axial image. Edema compressing the ventricle is present around the tuberculoma. Note the accompanying hydrocephalus.

Abnormality

Number

Percentage

Meningitis Hydrocephalus Meningitis + Hydrocephalus

3 5 1

11.1 18.5 3.7

rim. In contrast, the centers in lesions including cysticcentered caseating granulomas can be seen in a hyperintense signal [5–7,11–14]. In our study, tuberculomas including caseating cystic-centered granulomas were observed at a level of 85.9%, and those including noncaseating granulomas at a level of 14.1%; no tuberculomas including caseating solid-centered granulomas were identified. Tuberculomas may be present anywhere in the brain, although they are particularly found in the frontoparietal region and basal ganglions, and more rarely in the corpus callosum, quadrigeminal cistern, pontocerebellar angle, and retro-orbital [2,4,9,12]. Although localization in the cerebellar hemispheres and brainstem has rarely been reported, we determined cerebellar hemisphere involvement at a level of 26.5% and brain stem involvement at 9.5%. Edema and mass effect in surrounding tissues is a rare finding observed in the acute inflammatory stage and nonspecific in chronic tuberculomas. We determined a level of 4% in our study. 5. Conclusion

Three types of tuberculoma have been described: noncaseating, caseating with solid center, and caseating with cystic center, according to MRI findings [5,6]. Tuberculomas including noncaseating granulomas generally exhibit a relative low signal compared to the brain tissue on T1-weighted images and are seen hypointense on T2-weighted and fluid-attenuated inversion recovery (FLAIR) images. They generally exhibit homogeneous nodular contrast enhancement at contrast-enhanced examinations. Tuberculomas including caseating granulomas appear relatively hypo-isointense in T1-weighted images and in an iso-hypointense signal on T2-weighted images, and edema may be observed around them. These exhibit ring-like contrast enhancement in contrast-enhanced images. In T2weighted images, these lesions have a peripheral hypointense Table 1 The features of the tuberculomas Tuberculoma

Number

Percentage

N2.5 cm b2.5 cm Including caseating granuloma Including noncaseating granuloma Associated with edema In the cerebral hemisphere In the cerebellar hemisphere In the brainstem

6 58 55 9 4 41 17 6

9.3 90.6 85.9 14.1 6.2 64 26.5 9.4

Due to the increasing incidence in developing countries in particular, intracranial tuberculoma always represents a “doubtful pathology” in the differential diagnosis of intracranial and space-occupying lesions. Since it represents a highly fatal and difficult clinical picture, accurate analysis is of great importance. MRI makes a major contribution to diagnosis and is able to objectively determine accompanying abnormalities. Therefore, it must be one of the first diagnostic techniques applied when intracranial tuberculoma is suspected. References [1] Oncul O, Baylan O, Mutlu H, Cavusiu S, Doganci L. Tuberculous meningitis with multiple intracranial tuberculomas mimicking neurocysticercosis clinical and radiological findings. Jpn J Infect Dis 2005;58:387–9. [2] Desai K, Nadkarni T, Bhatjiwale M, Goel A. Intraventricular tuberculoma. Neurol Med Chir (Tokyo) 2002;42:501–3. [3] Bayindir C, Mete O, Bilgic B. Retrospective study of 23 pathologically proven cases of central nervous system tuberculomas. Clin Neurol Neurosurg 2006;108:353–7. [4] Yanardag H, Uygun S, Yumuk V, Caner M, Canbaz B. Cerebral tuberculosis mimicking intracranial tumour. Singapore Med J 2005;46: 731–3. [5] Huang CR, Lui CC, Chang WN, Wu HS, Chen HJ. Neuroimages of disseminated neurotuberculosis: report of one case. Clin Imaging 1999;23:218–22.

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[6] Tsugawa J, Inoue H, Tsuboi Y, Takano K, Utsunomiya H, Yamada T. Serial MRI findings of intracranial tuberculomas: a case report and review of the literature. No To Shinkei 2006;58: 225–30 [Abstract]. [7] Kilani B, Ammari L, Tiouiri H, Goubontini A, Kanoun F, Zouiten F, Chaabene TB. Neuroradiologic manifestations of central nervous system tuberculosis in 122 adults. Rev Med Interne 2003;24: 86–96. [8] Guzel A, Tatli M, Aluclu U, Yalcin K. Intracranial multiple tuberculomas: 2 unusual cases. Surg Neurol 2005;64:109–12. [9] Ozates M, Kemaloglu S, Gurkan F, Ozkan U, Hosoglu S, Simsek MM. CT of the brain in tuberculous meningitis. A review of 289 patients. Acta Radiol 2000;41:13–7.

[10] Gupta RK, Kathuria MK, Pradhan S. Magnetization transfer MR imaging in CNS tuberculosis. AJNR Am J Neuroradiol 1999;20: 867–75. [11] Kioumehr F, Dadsetan MR, Roohoiamini SA, Au A. Central nervous system tuberculosis: MRI. Neuroradiology 1994;36:93–6. [12] Gupta RK, Jena A, Singh AK, Sharma A, Puri V, Gupta M. Role of magnetic resonance (MR) in the diagnosis and management of intracranial tuberculomas. Clin Radiol 1990;41:120–7. [13] Jinkins JR, Gupta R, Chang KH, Rodriguez-Carbajal J. MR imaging of central nervous system tuberculosis. Radiol Clin North Am 1995;33: 771–86. [14] Pui MH, Ahmad MN. Magnetization transfer imaging diagnosis of intracranial tuberculomas. Neuroradiology 2002;44:210–5.