Intracranial tuberculomas: a CT study

Third ventricular tuberculoma mimicking as a tumor: Report of a very rare case

Intracranial tuberculoma is a common neurosurgical problem in developing countries; however, intraventricular tuberculoma is a rare entity. Here, we report a rare case of third ventricular tuberculoma in a 21-year-old girl who presented with features of raised intracranial pressure. Radiological findings and management of third ventricular tuberculoma would be discussed and literature regarding such lesions will be reviewed.

Frontal lobe tuberculoma

Tuberculomas are usually infratentorial in children, and supratentorial lesions predominate in adults. We present a 4-year-old girl with multiple seizures, papilloedema and brisk reflexes. On investigation, she was found to have a large left parafalcine tuberculoma. She was treated with antitubercular treatment (ATT) and steroids. The child improved, seizures stopped and the papilloedema gradually disappeared. Follow-up magnetic resonance imaging brain after 8 months showed a mild reduction in the size of the lesion. Child is on regular follow-up.

Intra cranial complications of tuberculous otitis media

Tuberculosis is one of the most common infections in the world. It is seen that tuberculous otitis media (TOM) is almost secondary to pulmonary tuberculosis. In this review we have tried to deal with all the aspects of the intra cranial complications of TOM such as tuberculoma, otitic hydrocephalus, brain abscess and tuberculous meningitis. The aspects covered in this review are the pathology, clinical features, and investigations of the intra cranial manifestations.

Disseminated tuberculosis with paradoxical miliary tuberculomas of brain in a child with rickets

Intracranial tuberculomas continue to be a serious complication of central nervous system tuberculosis. Multiple central nervous system tuberculoma is commonly associated with human immunodeficiency virus (HIV) infection. The development of intracranial tuberculomas has been thought to be caused by hematogenous spread of tubercle bacilli on the surface of brain parenchyma from the primary site of infection. Here, we describe the case of a 5-year-old male child with severe protein energy malnutrition (Marasmus) having large cervical lymphadenopathy and severe nutritional rickets with deformity at presentation. The child developed convulsions 20 days after initiation of antituberculous drugs, and neuroimaging confirmed multiple miliary tuberculomas of brain as primary etiology for the convulsions.

Clinico - diagnostic and therapeutic relevance of computed tomography scan of brain in children with partial seizures

Background:

Therapeutic relevance of computed tomography (CT) in children with partial seizures is reported to be remarkably low (1-2%). However, in the developing countries where infections involving the nervous system are common, routine CT scan of brain may help in finding treatable causes of seizures.

Objective:

Aim of this study was to evaluate the significance of CT scan of brain in the management of children with partial seizures.

Materials and Methods:

Children with partial epilepsy, whose predominant seizure type was focal motor seizures, were included in the study. CT scan of brain was done in all children aged between 1 month and 12 years with partial seizures of unknown etiology prospectively. The clinical findings of these children were noted along with the CT findings.

Results:

Between August 2001 and July 2002, of the 200 children with seizure disorder 50 children who satisfied the inclusion criteria were included in the study. CT scan of brain was normal in 16 children (32%) and was abnormal in 34 children (68%). Twenty children (~60% of abnormal scan) had potentially correctable lesions: Tuberculoma (n = 13), neurocysticercosis (n = 3), and brain abscess (n = 4). Five children had changes representing static pathology that did not influence patient management. The clinical features correlated with CT findings in 78% children.

Conclusion:

Children with partial motor seizures have high probability of having abnormal findings on CT scan of brain, especially, neuro-infections which are potentially treatable. Therefore, CT scan brain should be carried out in all children with partial motor seizures especially, in developing countries.

Neurocysticercosis: unraveling the nature of the single cysticercal granuloma

A single enhancing lesion in the brain parenchyma, also called an inflammatory granuloma, is a frequent neurologic diagnosis. One of the commonest causes of this lesion is human neurocysticercosis, the infection by the larvae of the pork tapeworm, Taenia solium. Following the demonstration that viable cysticercosis cysts survive in good conditions for several years in the human brain, single cysticercal granulomas have been consistently interpreted as representing late degeneration of a long-established parasite. On the basis of epidemiologic, clinical, and laboratory evidence detailed in this article, we hypothesize that in most cases these inflammatory lesions correspond to parasites that die in the early steps of infection, likely as the natural result of the host immunity overcoming mild infections.

DTI derived indices correlate with immunohistochemistry obtained matrix metalloproteinase (MMP-9) expression in cellular fraction of brain tuberculoma

We performed in vivo diffusion tensor imaging (DTI) in a total of 33 patients with brain tuberculomas (BT). Thirteen of them had surgical excision of the lesion as it was clinically indicated, and in these samples matrix metalloproteinase-9 (MMP-9) expression was quantified. We correlated the results of DTI indices like fractional anisotropy (FA), mean diffusivity (MD), linear anisotropy (CL), planar anisotropy (CP) and spherical anisotropy (CS) with MMP-9 expression. In addition, the remaining 20 patients had serial DTI studies while on specific anti-tuberculous drug therapy and DTI indices in these patients were quantified. The FA, CL and CP significantly decreased while MD and CS significantly increased in BT compared to normal white matter. The FA, CL and CP showed negative correlation with MMP-9 while CS correlated positively. In serial follow-up studies in 20 patients FA, CL and CP showed significant increase while CS decreased significantly over time. We conclude that DTI indices show strong correlation with MMP-9 and these may be used as a surrogate marker of MMP-9 expression in BT. In addition, these indices may be of value in assessing the therapeutic response in patients with BT who are treated only with specific anti-tuberculous drugs.

Assessment of therapeutic response in brain tuberculomas using serial dynamic contrast-enhanced MRI

AIM

To assess the most useful dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) index in the evaluation of the therapeutic response in brain tuberculoma (BT) patients.

SUBJECTS AND METHODS

Twenty-three patients with 25 BT lesions were serially evaluated using DCE MRI. All lesions were classified into two groups: group I (n=15) included patients who showed clinical, as well as imaging, improvement; and group II (n=10) included patients with either clinical or radiological deterioration. The group I and group II lesions were examined for up to 12 months at 4 monthly intervals. However, the lesions in five patients of group II were excised following clinical deterioration after 4 months of therapy. The perfusion indices, i.e., relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), permeability (k(trans)), and leakage (v(e)), were quantified at each time point. The cellular, necrotic, and total volumes of lesion, together with the oedema volume, were also calculated.

RESULTS

All patients in group I and three in group II showed a significant decrease in all perfusion indices, together with the oedema volume, after 1 year. In these three patients in group II, increase in rCBV was associated with increased cellular volume fraction whereas the k(trans), v(e), and oedema volume decreased significantly after 4 months. In five patients in group II who underwent excision of the lesion after 4 months of therapy due to clinical deterioration, the decrease in rCBV was associated with significant increase in k(trans) and oedema volume without any significant change in lesion volume. The rCBV correlated significantly with the cellular volume, whereas k(trans) showed a significant correlation with the v(e) and oedema volume at each time point.

CONCLUSION

In BT, changes in k(trans) and oedema volume are associated with a therapeutic response at 4 months, even when there is a paradoxical increase in the lesion volume.

Relative cerebral blood volume is a measure of angiogenesis in brain tuberculoma

OBJECTIVE

The aim of this study was to correlate the perfusion indices with magnetic resonance imaging-derived cellular and necrotic fraction of the tuberculoma and angiogenesis metrics on histopathology.

METHODS

We performed dynamic contrast-enhanced magnetic resonance imaging in 13 excised brain tuberculoma patients. Microvascular density and vascular endothelial growth factor (VEGF)-expressing cells were quantified from the excised tuberculoma. The cellular and necrotic fractions of the tuberculomas were quantified on a postcontrast T1-weighted imaging.

RESULTS

Relative cerebral blood volume of cellular portion significantly correlated with cellular fraction volume (r = 0.882, P < 0.001), microvascular density (r = 0.900, P < 0.001), and VEGF (r = 0.886, P < 0.001) of the 13 excised tuberculomas. Microvascular density also correlated significantly with VEGF (r = 0.919, P < 0.001).

CONCLUSIONS

Relative cerebral blood volume is a measure of angiogenesis in the cellular fraction of the brain tuberculoma. This information may be of value in predicting the therapeutic response in future.

Suprasellar tubercular abscess presenting as panhypopituitarism: a common lesion in an uncommon site with a brief review of literature

Following widespread use of imaging, detection rate of abnormal sites of parenchymal neuro-tuberculosis is on a rise. A handful of cases of tuberculomas/abscesses in hypothalamo-pituitary region have been reported and most of them are diagnosed on surgical histopathology. We describe a patient of suprasellar tubercular abscess, who presented with visual disturbances, diabetes insipidus with panhypopituitarism and on histopathology had granulomas and positive acid fast bacilli.

Paradoxical intracranial tuberculoma requiring surgical treatment

Paradoxical enlargement of intracranial tuberculomas or development of new ones during adequate antituberculous chemotherapy is an uncommon event. Treatment of such cases is controversial. Steroid therapy is usually advocated without change in the antituberculous drug program. However, in some patients whose lesions fail medical treatment, or who have superficially located large lesions, surgical therapy may be required. A 15-year-old girl with pulmonary miliary tuberculosis, tuberculous meningitis and multiple intracranial tuberculomas is presented. While her pulmonary lesions and intracranial tuberculomas except one were healed with chemotherapy, one tuberculoma increased in size 1 month after starting chemotherapy. She was followed with dexamethasone treatment in addition to antituberculous therapy for 2 months. Then, the lesion was removed because it had increased in size in spite of appropriate chemotherapy.

Modern imaging of tuberculosis in children: thoracic, central nervous system and abdominal tuberculosis

Tuberculosis (TB) can affect any organ in the body. Children are a high-risk group for contracting the disease and pose a constant challenge to clinicians with regard to making a definitive diagnosis. Radiologists are playing a more active role in diagnosing TB, and armed with more accurate diagnostic investigations such as CT and MRI, they must face the cost implications as well as technical limitations. This review aims to guide the reader through the modern imaging techniques useful for diagnosing TB of the thorax, central nervous system and abdomen in children. The more specific features of each modality in the particular anatomical regions are highlighted.

Cranial computed tomography in partial motor seizures

OBJECTIVE

To identify the pattern of intracranial structural lesions in developmentally normal children with partial motor seizures by computed tomography and to monitor the behavior of single ring enhancing lesion (SREL) after a period of time with or without treatment.

METHODS

Consecutive developmentally normal children between one year and twelve years with partial motor seizures in a tertiary care referral Hospital. After clinical examination and appropriate investigation for tuberculosis and cysticercosis, CT scan was performed. In addition to anticonvulsants, children received antituberculous or anticysticercal therapy if indicated. Repeat CT was performed on children with SREL after 6 months.

RESULTS

Computed tomography was abnormal in 102 (68%) children. Majority of the children (75) had SREL. The lesions were located in decreasing order of frequency in the parietal lobe (65), frontal lobe (7), occipital lobe (1), temporal lobe (1) and cerebellum (1). Repeat CT scan was performed on 50 of the 75 children with SREL. Among these, in 41 children who were only on antiepileptic therapy, the SREL had decreased in size in thirty-two whereas in the rest (9), there was no change in the size.

CONCLUSION

Awareness of the existence of disappearing SREL lesions is essential to avoid unnecessary treatment with antituberculous or anticysticercal therapy and provides ample justification in treating with anticonvulsant drugs only.

Solitary cerebral cysticercus granuloma

Solitary cerebral cysticercus granuloma (SCCG) is one of the commonest causes of seizures in Indian patients. SCCG has been confused in the past with tuberculomas, but by applying a set of diagnostic criteria proposed by the author, they can be diagnosed accurately in the vast majority of patients. Patients with SCCG are managed effectively with antiepileptic drugs (AEDs). The role of cysticidal drugs in their management is controversial. SCCG resolves spontaneously at a variable rate and has a good seizure outcome, with >90% of patients remaining seizure free after discontinuation of AEDs.

Comparative evaluation of magnetization transfer MR imaging and in-vivo proton MR spectroscopy in brain tuberculomas

We have compared and analyzed the value of in vivo proton MR spectroscopy (PMRS) and T1 weighted magnetization transfer (MT) MR imaging in tissue characterization of brain tuberculomas. We studied 33 cases of proven intracranial tuberculomas with in vivo PMRS and T1 weighted MT MR imaging. MT ratios from the rim and core of the tuberculomas were calculated and compared with metabolites seen on PMRS. Final diagnosis of tuberculoma was based on histopathology (n = 26) and/or associated tuberculous meningitis (n = 7) in all the cases. Out of the 33 patients who underwent both PMRS and T1 weighted MT MR imaging, spectroscopy showed only lipids at 0.9 ppm, 1.3 ppm, 2.0 ppm, and 2.80 ppm in 26 cases while lipids at 0.9 ppm, 1.3 ppm, 2.0 ppm and 2.80 ppm along with choline at 3.22 ppm was seen in remaining 7 patients. MT ratios from the core or solid necrosis varied from 21-29% while from the rim or cellular region varied from 16-24%. MT ratios from all the 33 lesions were consistent with tuberculomas while PMRS showed choline along with lipids in 7 predominantly cellular lesions simulating a neoplasm. We conclude that T1 weighted MT MR imaging appears to be more consistent in the tissue characterization of brain tuberculomas.

Prognosis of epilepsy associated with single CT enhancing lesion: a long term follow up study

This is a retrospective analysis to study the long term prognosis of epilepsy associated with single CT enhancing lesion (SCTEL). Follow up CT scan showed resolution of the lesion in all of the 102 patients. Seizures did not recur in 64 (63%) patients after starting antiepileptic drugs. Twenty eight (27.5%) patients had recurrence of seizures for a median period of 2 months before remission was achieved. In the remaining ten (10%) patients seizures remitted only after albendazole therapy and the median period of seizure recurrence was 8 months. Sixteen (42%) of the 38 patients who had recurrence of seizures had type B CT lesion (ring lesion with central enhancing area, probably scolex) (P<0.02 (95% CI 3.2-40.3)). Patients with type B CT lesion had more numbers of seizures and also longer intervals between first and last seizure. Antiepileptic drugs were withdrawn in all the 102 patients. The mean period of follow up was 45 months (range 19-101). Only one patient had a relapse and his follow up CT showed gliotic scar at the site of the previous lesion. We conclude that epilepsy associated with SCTEL is a benign form of epilepsy and seizures recur as long as the lesion persists. Antiepileptic drugs can safely be withdrawn once the follow up CT shows resolution of the lesion.

The syndromic classification of the International League Against Epilepsy: a hospital-based study from South India

PURPOSE

To determine the distribution of various epilepsies and epileptic syndromes in the epileptic population treated in a university hospital in a developing country.

METHODS

Data concerning 2,531 patients with epilepsy seen between January 1989 and June 1994 were analyzed using the International League Against Epilepsy (ILAE) classification.

RESULTS

Of 2,531 cases, 48% fell into ILAE categories 1.3, 3.2, or 4.1 (cryptogenic, without unequivocal generalized or focal seizures; or situation-related seizures, respectively). Localization-related epilepsies (LREs) and epileptic syndromes (1.1, 1.2, 1.3) were found in 1,591 (62.9%) patients; of these patients, symptomatic localization-related epilepsies totaled 62.7%. and idiopathic localization-related epilepsies accounted for only 0.7%. Juvenile myoclonic epilepsy was the most common type of idiopathic generalized epilepsy (IGE), comprising 4.9% of the total study population and 7.7% of patients registered in the epilepsy clinic. A combination of childhood and juvenile absence epilepsies were found in only 0.4% of the total study population. Single computed tomography (CT) enhancing lesion (SCTEL) and focal cerebral calcification (FCC) accounted for 22% of the etiologic factors for localization-related epilepsies. Neurologic deficits were found in 9.5% of patients with SCTEL; none were found with FCC. None of the patients with these lesions had any history of antecedent events that suggested CNS involvement. In patients with localization-related epilepsies with unremarkable clinical data, the proportion of CT scans showing SCTELs was 39 (95% confidence interval [CI], 0.35-0.43) and 0.18 (95% CI, 15-0.21) for FCCs. The proportion for both lesions together was 0.57 (95% CI, 0.53-0.61). Seizures did not recur once the lesion resolved in patients with SCTELs. In patients with FCCs, seizure remission was 71.5% (95% CI, 53.7-85.4) at 3 years.

CONCLUSIONS

This study illustrates the rarity in one patient population of some of the syndromes and categories described in the ILAE classification. Childhood and juvenile absence epilepsies together formed a small proportion. SCTEL and FCC were important etiologic factors for localization related epilepsies. The epilepsy associated with SCTEL was a form of benign epilepsy; epilepsy associated with FCC had remission rates similar to other remote symptomatic epilepsies. Without neuroimaging evidence, these 2 lesions would have been missed and the patients might have been grouped under cryptogenic localization related epilepsy. For this reason, we emphasize the need for neuroimaging in patients with localization related epilepsies with unremarkable clinical findings, before classification into the cryptogenic category. In the absence of neuroimaging, such patients should be classified as "probably cryptogenic."

Cerebral tuberculosis in patients with the acquired immunodeficiency syndrome (AIDS). Report of 6 cases and review

Cerebral tuberculosis (TB) was diagnosed in 6 (4%) of 156 HIV-infected patients with TB seen at our institution over 6 years. We describe here the clinical and radiologic features of these cases and of 15 others reported in the literature. Of the 21 patients, 59% were intravenous drug users. Presenting symptoms were fever (76%), confusion (52%), seizures (38%), and headache (38%). Fourteen patients (66%) had previous or active extracerebral TB at presentation. Cranial CT scan showed ring-(62%) or nodular-(24%) enhancing lesions or mixed forms (14%). Among the 12 patients who underwent a brain biopsy, bacteriologic evidence of TB was found in 9. Four patients (19%) died during hospitalization. Among the 17 others who received antituberculous therapy, only 1 developed neurologic sequelae. Five patients also received steroid therapy to control cerebral edema or paradoxical growth of the cerebral mass lesions. TB should be considered as a cause of cerebral mass lesions in HIV-infected patients, especially if tuberculous infection is suspected at other sites.

CT in simple partial seizures in children: a clinical and computed tomography study

INTRODUCTION

Therapeutic relevance of computed tomography (CT) in children with simple partial seizures (SPS) is reported to be remarkably low (1-2%). There are not studies, however, from the developing countries where neuroinfections are among important causes of seizures. The present study from India is aimed at evaluating the significance of CT in the management of SPS in children and to determine the difference in clinical features of children with and without focal brain lesions in CT.

PATIENTS AND METHODS

CT scans of all patients aged 15 years of younger with SPS, seen over a period of 15 months, were reviewed. The clinical features of the patients with focal lesions in the CT were compared with those of children without focal abnormalities.

RESULTS

Focal structural lesions were present in 117 (59.09%) of 198 children. These included: solitary contrast enhancing CT lesion-16.16%, focal calcification-12.12%, cysticerosis-10.10%, focal atrophy-9.59%, tuberculoma-6.56% and infarction-6.06%. Neuroinfections or their sequelae were responsible for seizures in 89 children (44.94%). There were no statistically significant differences in clinical features of patients with and without focal lesions in CT.

CONCLUSIONS

CT study in children with SPS in developing countries has significant therapeutic relevance. It is not possible to clinically differentiate children with focal lesions from those without focal lesions in CT.

A controlled clinical trial of short-course chemotherapy for tuberculoma of the brain

OBJECTIVE

The efficacy of a short-course regimen in the treatment of brain tuberculoma and computerised tomography (CT) scan appearance before, during and after antituberculosis treatment was studied in a controlled clinical trial.

DESIGN

Patients aged over 5 years with tuberculoma of the brain diagnosed by CT scan were randomly allocated to one of the following 2 regimens: Regimen 1: rifampicin, isoniazid and pyrazinamide daily for an initial 3 months followed by rifampicin and isoniazid twice-weekly for 6 months. Regimen 2: rifampicin, isoniazid and pyrazinamide thrice-weekly for an initial 3 months followed by rifampicin and isoniazid twice-weekly for 6 months. The patients were followed intensively for 2 years from the start of treatment.

RESULTS

Of the 108 patients analysed (regimen 1: 56, regimen 2: 52), at the end of treatment clinical status was normal in 91% in regimen 1 and 88% in regimen 2. Of the 91 patients with scan assessments, CT scan lesions disappeared at 24 months in 77% of 47 patients in regimen 1 and 80% of 44 in regimen 2, and in both groups 88% of the patients were clinically normal. None had relapses requiring treatment.

CONCLUSIONS

Short-course regimens of 9 months' duration are effective in the treatment of tuberculoma of the brain; clinical recovery was faster than scan clearance.

Imaging intracranial tuberculosis in childhood

A morphologically based imaging review of intracranial tuberculosis in childhood is presented. The computed tomography and magnetic resonance features of parenchymal tuberculoma, tuberculous meningitis and meningeal/meniningocerebral tuberculoma are illustrated. Recent insight into the nature of tuberculoma necrosis and its magnetic resonance correlation is reviewed. Pathogenesis, relevant clinical background and the role of modern imaging is discussed.

Predictive value of computed tomography-based diagnosis of intracranial tuberculomas

The need to obtain histological diagnoses of intracranial tuberculomas, before initiating therapy, is not universally accepted, because some clinicians believe that an image-based diagnosis is fairly accurate in patients from endemic regions. To evaluate the sensitivity, specificity, and predictive value of computed tomography (CT)-based diagnosis of an intracranial tuberculoma, we prospectively compared the preoperative imaging diagnoses with histological diagnoses in 105 consecutive patients with intracranial masses. CT differential diagnoses (first or second) of tuberculomas were considered in 21 patients. Seven of them were histologically confirmed to have tuberculomas (true-positive results); 14 had other diseases (false-positive results). The 14 false-positive cases included 6 cases of astrocytomas, 5 of metastases, and 3 with miscellaneous diagnoses. All tuberculomas were correctly diagnosed on the CT scans (5 by both surgeons and 2 by one surgeon). During the study period, we encountered 11 patients who were referred by other clinicians with diagnoses of tuberculomas on the basis of their CT scans. We concurred with their CT diagnoses in 5 of them, but only 1 patient had a histologically verified tuberculoma. Astrocytomas (4 patients), metastases (3 patients), and solitary cysticercus granulomas (3 patients) were the causes of misdiagnosis in this group of patients. Although the sensitivity of CT in the diagnosis of intracranial tuberculomas is 100%, and its specificity is 85.7%, the positive predictive value is only 33% (confidence limits, 24-42%). The negative predictive value is 100%. The low positive predictive value for a diagnosis of intracranial tuberculoma on CT alone indicates the need for a confirming histological diagnosis.

Balo's concentric sclerosis diagnosed intravitam on brain biopsy

A 28-year-old woman presented with acute right hemiparesis evolving to bilateral hemiplegia and a mute state within 1 week on a background of paranoid psychosis of 8 years duration. CT scan revealed multiple bilateral hypodense enhancing lesions in the central white matter. Biopsy of the lesion showed lamellar alternating zones of demyelination and remyelination, typical of Balo's concentric sclerosis, an acute variant of multiple sclerosis. Immunohistochemical staining for neurofilament showed greater damage to the axis cylinders by the disease than generally perceived by silver stains. Steroid therapy produced a gratifying and sustained improvement. Follow up CT scans and psychometry revealed regression of the demyelinating lesions and improvement of the cognitive state.

Differentiating solitary small cysticercus granulomas and tuberculomas in patients with epilepsy. Clinical and computerized tomographic criteria

It is commonly believed that differentiating solitary small cysticercus granulomas and small tuberculomas in patients with seizures is difficult without resorting to an excision biopsy. The aim of this study was to formulate clinical and computerized tomography (CT) criteria to distinguish these two entities in patients with epilepsy. Toward this end, clinical and CT data from six consecutive patients with histologically proven small solitary tuberculomas and 25 consecutive patients with histologically proven solitary cysticercus granulomas were compared. Evidence of raised intracranial tension and a progressive focal neurological deficit was seen only in patients with tuberculomas (two of six cases). All tuberculomas were greater than 20 mm in size and five of the six were irregular in outline. Only tuberculomas were associated with a midline shift on CT (four of six cases). All cysticercus granulomas were less than 20 mm in size and 24 (96%) of the 25 were regular in outline, conforming to one of two characteristic patterns. No cysticercus granuloma was associated with a midline shift. Based on the above clinical findings (evidence of raised intracranial tension and a progressive neurological deficit) and CT criteria (size, shape, and association with a midline shift), it is possible to separate these two entities in a majority of patients with seizures and with a single small lesion on CT.

Vanishing CT lesions in epilepsy

Experience with computed tomography (CT) in patients with epilepsy has drawn attention to specific type of cerebral lesions widely prevalent in this part of the world. The lesions disappear spontaneously while patients receive only anticonvulsant therapy. The exact nature of these lesions is not yet understood. One-hundred and twenty-two such patients (M 77; F 45) were studied. Their age ranged from 3 to 57 (mean 21.8 +/- 12.7) years. Seizures were partial motor in 86 (70.5%), generalised tonic clonic in 31 (25.4%), complex partial in 4 and atonic in one case. Postictal hemiparesis was seen in 6 patients who completely recovered within 5 min to 7 days. One hundred patients underwent EEG examination. It was abnormal in 84 cases; 40 patients showed localisation which correlated with CT findings. Plain CT showed low attenuation lesions in all cases. Morphology on contrast enhancement was ring lesion in 50 (40.9%), disc lesion in 47 (38.5%), target lesion in 3 (2.5%), mixed lesion in 2 (0.8%), no enhancement in 18 (14.8%) and a speck with oedema in 2 (0.8%) cases. All lesions were cerebral, present at cortical-subcortical junction. The first follow-up scan was performed in 78 (63.9%) patients within 6-12 weeks. It showed complete disappearance of the lesion in 47 (60.3%) cases. Reduction in size of the lesion and surrounding oedema was observed in 24 (30.8%) cases. The follow-up scans in these 24 cases revealed disappearance of lesion in 11 cases and almost complete resolution of the lesion with a remaining speck in 13 cases. Cerebrospinal fluid (CSF) was normal in 95 out of 100 cases in which it was performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Etiology and management of single small CT lesions in patients with seizures: understanding a controversy

Single, small (less than 1 cm) enhancing lesions are frequent findings on CT scans of Indian patients with seizures. These lesions have also been reported in patients from other parts of the world. They often resolve spontaneously and their etiology has been disputed for over a decade. Initially diagnosed in Indian patients as tuberculomas, a number of other etiologies have been suggested. More recently, based on biopsy data, we have shown that a majority of these lesions are caused by cysticercosis. This review traces the development of the controversy and reports the current understanding of their etiology. A logical approach to their management is also discussed.

Angiostrongylus cantonensis abscess in the brain

Images

[Non tumor intracranial expansive processes: clinico-topographical correlation]

Presentation of clinical-tomographic correlation in 111 cases of non tumoral intracranial expansive processes seen between 1984-1988 in the Hospital Cayetano Heredia (Lima, Peru). Emphasis is given fundamentally to: (1) the importance of establishing the organicity of partial and late epilepsy; (2) the high incidence rate of inflammatory infectious processes with CNS compromise in underdeveloping countries; (3) the necessity of making public the importance of two parasitic diseases in the differential diagnosis of non tumoral intracranial expansive processes: free living amebiasis, and toxoplasmosis (especially in association with AIDS).

Computed tomography of intracranial tuberculosis

The many clinico-radiological manifestations of intracranial tuberculosis have been well documented; however, few long-term retrospective serial studies of large series of patients on therapy have been reported utilizing computed imaging. The computed tomographic appearance, sequential periodic evolution, and final outcome of all patients with cranial tuberculosis seen at this institution in a period of ten years have been evaluated. A total of 80 subjects with intracranial tuberculosis revealed 17.5% with Type I isolated meningeal involvement, 71.25% with Type II isolated parenchymal forms, and 11.25% with Type III compound parenchymal/meningeal lesions. Only 28.8% had concomitant manifestations of TB outside the CNS. Seventy four of these patients were followed on medical or combined medical/surgical therapy which demonstrated 24.3% (n = 18) resolution without radiographic sequellae, 66.2% (n = 49) resolution with residual stroke, atrophy and/or calcification, and 4.1% (n = 3) with persistent enhancement of the lesion(s) after two years of treatment. Four deaths occurred all of which were in patients with Type III TB. This large group of patients followed from presentation to radiologic resolution of the disease process by computed tomography yields important information on the presentation, prognosis and sequelae of intracranial tuberculosis.

Role of magnetic resonance (MR) in the diagnosis and management of intracranial tuberculomas

Thirty-one patients with intracranial tuberculomas were diagnosed on the basis of magnetic resonance (MR) imaging. The diagnosis was confirmed in 30; one case was a false-positive. A total of 44 tuberculomas was found in these patients of which 41 were distributed in the cerebral hemispheres, two in the brainstem and one in the cerebellum. No correlation was found between the type of lesion seen on CT and those seen on MR imaging. CT was negative in one patient with a low brainstem tuberculoma. The final diagnosis was based on the response to antituberculous drug treatment as judged by serial MR imaging in 29 patients and by biopsy in one; and one was false-positive. Thirty-nine tuberculomas, all under 2.5 cm in size, showed complete resolution after 5-8 months of treatment. The remaining five lesions were larger than 2.5 cm; four showed a 50% reduction in size after 12 months of treatment and one was completely excised. Three types of response are described to the treatment with anti-tuberculous drugs. The diagnosis of intracranial tuberculomas can be made more objectively with MR imaging.

Avoiding empiric therapy for brain masses in Indian patients using CT-guided stereotaxy

Empiric therapy, especially antituberculous therapy, is frequently given to Indian patients with brain masses. This report documents our experience in avoiding such therapy using CT-guided stereotaxy. Out of 101 procedures done on 99 patients with brain masses, 80 were done to obtain a histological diagnosis and 21 for therapeutic purposes. There was no mortality and 2% morbidity. A positive diagnosis was obtained in 94% (75/80) of patients undergoing a biopsy. Diagnosis of tuberculous lesions was based mainly on the presence of acid-fast bacilli in the biopsy specimen or pus. In six patients the radiological diagnosis was wrong and in one the diagnosis was not certain. Inappropriate therapy was given to three patients, on the basis of a CT or MRI scan, before a biopsy was done. It is essential that a histological diagnosis be obtained in all patients with brain masses and there is no role for empirical therapy except in isolated cases.

Gd-DTPA enhanced MR imaging in intracranial tuberculosis

Twenty-six patients with intracranial tuberculosis (Tb) (10 with acute meningitis, 5 with chronic meningitis, 5 with meningitic sequelae and 6 with localized tuberculoma(s)) were examined with MR before and after Gd-DTPA enhancement (0.1 mmol/kg), using 2.0T superconducting unit, and the images were retrospectively analyzed and compared with CT scans. Without Gd-DTPA enhancement, the MR images were generally insensitive to detection of active meningeal inflammation and granulomas. The signal intensity of granulomas was usually isointense to gray matter on both T1- and T2-weighted images, whether they were associated with diffuse meningitis or presented as localized tuberculoma(s). A few granulomas showed focal hypointensity on T2-weighted images. Calcifications seen on CT of the meningitic sequelae group usually appeared markedly hypointense on all spin-echo sequences. On Gd-DTPA enhanced T1-weighted images, abnormal meningeal enhancement indicating active inflammation was conspicuous, and the granulomas often appeared as conglomerated ring-enhancing nodules, which seems to be characteristic of granulomas. Thin rim enhancement around the suprasellar calcifications were observed in two out of 5 patients with meningitic sequelae. Compared with CT, MR detected a few more ischemic infarcts, hemorrhagic infarcts, meningeal enhancement and granulomas in the acute meningitis group, but missed small calcifications in the basal cisterns well shown on CT in the sequelae group. Otherwise, MR generally matched CT scans. MR imaging appears to be superior to CT in evaluation of active intracranial Tb only if Gd-DTPA is used, while CT is better than MR in evaluating meningitic sequelae with calcification.

Tuberculous abscess of the brain stem

Three cases of tuberculous abscess of the brain stem were treated with excision of the abscess supplemented with antitubercular therapy for 12 to 18 months. The lesions were frankly purulent and tubercle bacilli were demonstrated in the pus. A computed tomography scan demonstrated the site and extent of the lesion. Two of three patients developed the abscess during the course of antitubercular therapy for associated tubercular lesions. In spite of modern antitubercular treatment the abscess did not resolve and surgical excision had to be employed as a curative treatment.