Comparative Study Evaluating the In Vivo Characteristics of Ruptured and Unruptured Aneurysms Using serial Digital Subtraction Angiography.

Over the past decade preventive endovascular treatment is increasingly being considered for intracranial aneurysms irrespective of whether ruptured or unruptured. Few studies have dealt with in-vivo characteristics of intracranial aneurysms. We compare the angiographic morphology of ruptured and unruptured intracranial aneurysms using short interval serial DSA. 37 patients with intracranial aneurysms and who underwent at least two digital subtraction angiograms were included in the study. Based on the clinical presentation there were two subgroups of patients, Group A patients presenting acutely with Sub arachnoid haemorrhage (SAH) and Group B patients who had no clinical or imaging features suggestive of bleed. Clinical and serial angiographic data were correlated. Aneurysms in Group A (1.04 mm(3)) were significantly (p=0.010) smaller than in Group B (4.53 mm(3)). Aneurysms in group A showed increase in size and those in Group B showed a decrease in size (p=0.019). Hypertensive patients in both the groups showed a tendency for a decrease in the size of the aneurysms. Aneurysms having stasis at the time of initial angiogram had significantly reduced in size on follow up (p=0.013) at a faster rate (p=0.017). Presence of spasm in adjacent vessels was associated with increase in size of aneurysm on follow up in both Groups. There are significant differences between a ruptured aneurysm and an unruptured one. Ruptured aneurysms are small and show rapid increase in size. The presence of spasm increased the size of the aneurysm in the post rupture period and anti hypertensive medication and stasis were associated with decrease in size.

Automated MRI parcellation study of regional volume and thickness of prefrontal cortex (PFC) in antipsychotic-naïve schizophrenia.

OBJECTIVE: Prefrontal cortical dysfunction is considered to be critical in the pathogenesis of schizophrenia. However, structural magnetic resonance imaging (MRI) studies on the PFC have yielded inconsistent results because of various confounding factors. METHOD: In this study we examined the volume and thickness abnormalities of the PFC in antipsychotic-naïve schizophrenia patients (n = 51) in comparison with age-, sex-, and handedness-matched (as a group) healthy comparison subjects (n = 47) using a newly described automated MRI parcellation analysis. RESULTS: Schizophrenia patients showed i) significant volume deficits in bilateral lateral orbitofrontal and left medial orbitofrontal cortices as well as bilateral pars triangularis; and ii) significant thickness deficit in bilateral medial orbitofrontal cortices. Negative syndrome score had a significant negative correlation with the thickness of the left medial orbitofrontal cortex. CONCLUSION: The study findings emphasize that prefrontal deficit in schizophrenia is differential and involves primarily the regions essential for 'social cognition'.

Stroke with supernumerary phantom limb: case study, review of literature and pathogenesis.

OBJECTIVE: Constitute hypothesis for origin of supernumerary phantom limb (SPL) after stroke. METHOD: Single case description, review of literature and formulation of hypothesis. RESULTS: A 59-year-old lady was evaluated for complaints of left-sided hemiparesis and extra limbs attached to her left shoulder for the past 7 months. Neuropsychological assessment revealed left hemineglect with SPL, and profile suggested bilateral frontal, right parietotemporal and basal ganglia involvement. Magnetic resonance imaging brain scan showed gliotic cavity secondary to the old haematoma in right putamen with white matter changes in the right frontoparietotemporal lobes. CONCLUSIONS: The conceptual framework of body schema can be used to classify many of the neurological disorders of body representation. Generation of SPL comes under the subtype of pathology of updating among the disorders of body schema. The continuous updating allows the body schema to modulate perceptual processing of objects according to their position in space. Brain areas classified as parts of motor system can, under pathological conditions (haemorrhage), influence body perception. So, when she used to move her arm, the representation of the estimated position was not updated by the motor commands. Sensory and motor information therefore becomes discrepant, and failure to integrate these two sources of information leads to loss of normal coherence, and the perceived shape of the body was altered by adding a SPL to accommodate the discrepancy.

Chiari 1 malformations: an Indian hospital experience.

INTRODUCTION: A consensus on the ideal surgical procedure for Chiari 1 malformation has not been achieved. The purposes of the study were to report on the experience of treating this condition in an Indian hospital, and to look into the management of this not too uncommon condition with a view to improve the treatment and prognosis. METHODS: A retrospective case note study of all cases of Chiari 1 malformations operated over a ten-year period from 1989 to 1999 and followed-up for another two years, were analysed for clinical and radiological features. All patients who underwent posterior fossa decompression were included. Patients who underwent other procedures like shunts were excluded. The data obtained included clinical and radiological features. RESULTS: A total of 51 cases were analysed. All patients had posterior fossa decompression with duroplasty in the majority. Many patients had a delayed improvement noticed during the follow-up period. Headache, neck pain and motor features showed an improvement in the majority of the patients but sensory deficits did not. CONCLUSION: This study showed the effectiveness of posterior fossa decompression with duroplasty as a procedure, which benefited most patients with Chiari 1 malformations.

Intrathecal gadolinium-enhanced magnetic resonance cisternography in cerebrospinal fluid rhinorrhea: road ahead?

Accurate localization of cerebrospinal fluid (CSF) fistula in a patient with CSF rhinorrhea is challenging and often involves multiple imaging studies with associated expense and patient discomfort. Intrathecal contrast-enhanced computed tomography (CT) and unenhanced magnetic resonance (MR) cisternography using constructive interference in steady state (CISS-3D) sequences are currently being used in attempt to localize the leakage site but with varying degrees of success. Our purpose is to evaluate the utility of intrathecal gadolinium-enhanced MR cisternography (GdMRC) in patients with CSF rhinorrhea. Ten consecutive patients of CSF rhinorrhea (five spontaneous, four post-traumatic, and one post-operative) were evaluated with GdMRC. Nine of the patients underwent intrathecal contrast CT and CISS-3D examinations in addition. Each of studies was reviewed independently by three neuroradiologists blinded to results of other modalities. Surgery was planned after consensus and surgical correlation obtained in nine cases. The fistulous site was clearly demonstrated by using GdMRC in eight patients, CISS-3D in six, and intrathecal CT in three patients. The site of leakage was confirmed surgically in all the patients. One patient was found to be false negative both by intrathecal CT and GdMRC, and in one patient no fistulous site was demonstrated by any of the modalities and surgery was not offered. No adverse reaction was seen in any of the patients. GdMRC is a novel method of confirmation and localization of CSF fistula with potential for routine clinical application. Diagnosis and localization of fistulous site is better demonstrated due to its high-contrast resolution, absence of bony artifacts, and direct multi-planar imaging.

Neurohydatidosis.

Early and non-invasive evaluation of hydatid infestation of brain and spine is of paramount importance, especially in endemic areas. We present a spectrum of imaging findings in neurohydatidosis with a brief review of literature.

T2 relaxometry of ring lesions of the brain.

AIM: To differentiate two common aetiologies of "ring lesions," tuberculomas and cysticercal cysts, using T2 relaxometry. MATERIALS AND METHODS: Fifty-five ring-enhancing lesions of the brain (32 cysticercal cysts; 23 tuberculomas) in 27 patients with focal seizures were studied for T2 relaxation times. RESULTS: The mean T2 relaxation times of cysticercal cysts was 617 ms (range 305-1365 ms; SD 272.2) and that of tuberculomas 161 ms (range 83-290 ms; SD 60.3; 95% confidence). CONCLUSION: T2 relaxometry is a simple, reliable and valuable non-invasive magnetic resonance imaging (MRI) technique to differentiate between intracranial cysticercal cysts and tuberculomas, and may be incorporated in routine diagnostic protocols.

Quantitative magnetic resonance techniques in the evaluation of intracranial tuberculomas.

PURPOSE: To evaluate intracranial tuberculomas using quantitative magnetic resonance (MR) techniques such as T2 relaxometry, magnetization transfer (MT), and diffusion-weighted imaging (DWI). MATERIAL AND METHODS: Thirty-three patients with intracranial tuberculomas (histologically confirmed in 22) were evaluated using proton density/T2-weighted, T1-weighted (with and without MT), and echo-planar diffusion-weighted imaging sequences. T2 relaxation times, MT ratios (MTR), and apparent diffusion coefficient (ADC) values were calculated from the center of the lesion, the periphery, perilesional edema, and contralateral normal white matter. The mean and standard deviation values of each variable were calculated and correlated using Pearson's test (P = 0.05). RESULTS: The measured mean values of T2 relaxation time, MTR, and ADC in the center of lesions were 155.5 ms, 14.1, and 1.27 x 10(-3) mm(2)/s, respectively, compared to 117 ms, 23.72, and 0.74 x 10(-3) mm(2)/s in normal white matter, and a T2 relaxation time of 187.45 ms in normal gray matter. Significant inverse correlations were noted between T2 relaxation values and MTR (P<0.001) and between MTR and ADC (P = 0.046). Significant positive correlation was seen between T2 relaxation and ADC values (P = 0.03). CONCLUSION: Intracranial tuberculomas are characterized by relatively short T2 relaxation times (compared to normal gray matter), decreased MTR, and mostly no restriction of diffusion. A combination of these quantitative parameters could be of help in the noninvasive diagnosis of tuberculomas.

Clinicoradiological features of tuberculous meningitis in patients over 50 years of age.

BACKGROUND AND AIMS: Tuberculous meningitis (TBM) is a debilitating form of CNS tuberculosis with a high morbidity and mortality in spite of treatment. The diagnosis is based on clinical, radiological and laboratory features. The classical CT features of basal exudates, hydrocephalus, infarcts and granulomas have been mostly reported in younger individuals. Our aim was to study imaging features of TB meningitis in adults over the age of 50 years. MATERIALS AND METHODS: Clinical, imaging and laboratory features of 53 adult patients over the age of 50 years (sixth to eighth decades) were studied retrospectively. Diagnosis of TBM was based on clinical and laboratory features. RESULTS: Imaging features were the conspicuous absence of typical features of TBM (ie, basal meningeal enhancement, hydrocephalus, infarcts/granulomas were seen in only a minority of patients). CONCLUSIONS: CT features of TBM in elderly patients were few, atypical and non-contributory for diagnosis, probably because of age related immune senescence. Strong clinical suspicion and correlation with laboratory findings is necessary for early diagnosis.

Restricted diffusion in Canavan disease.

INTRODUCTION: Canavan disease is a megalencephalic leukodystrophy due to deficiency of the enzyme aspartoacylase. Proton MR spectroscopy finding of elevated N-acetyl-L: -aspartate is considered diagnostic of Canavan disease. CASE REPORT: We report a case of Canavan disease, which showed restricted diffusion in diffusion-weighted imaging and discuss the cause of it.

CT Perfusion in Spinal Disease: an Adjunct Tool to Vertebral Body Biopsy.

Routine diagnostic techniques are inadequate for diagnosis of spinal diseases. The purpose of this study was to determine whether CT perfusion can differentiate inflammatory diseases like tuberculosis from neoplastic diseases of spine. Thirty-two patients with vertebral body lesions associated with paraspinal mass underwent CT guided bone biopsy and histopathological evaluation. CT perfusion was done in all patients before doing biopsy. Perfusion parameters like blood volume (BV), blood flow (BF) and time to peak (TTP) were calculated and correlated with histopathology. Statistical analysis was done using Mann-Whitney test. p value <0.05 was considered significant. Of 32 cases, 20 had tuberculous osteomyelitis and 12 neoplastic disease (seven metastasis, three plasmacytoma, one each lymphoma and chordoma). Mean rBF was [inflammatory lesions, 1.459 and neoplastic lesions, 18.080 (p<0.000). Mean rBV was (inflammatory disease, 2.8589 and neoplastic lesions, 12.2133 (p<0 .000)). Mean rTTP was [inflammatory pathology, 1.041 and neoplastic pathology, 0.703(p<0.079)]. This shows the deconvolution-based CTP technique's potential for noninvasive diagnosis of at least all inflammatory lesions affecting the spine that are associated with paraspinal mass. Validation of the use of deconvolution CTP parameters for differentiation of inflammatory from neoplastic pathology may permit this technique to be used as an adjunct tool when biopsy when routine imaging findings are inconclusive.

Orbital Cysticercosis: Comparing Multi-Slice CT and Steady State MR to Identify Scolex.

Orbital cysticercosis with both ocular and extraocular involvement is common in endemic areas. The presence of scolex is considered diagnostic of cysticercosis. We sought to compare multi-slice CT and 3D steady state MR in the identification of scolex in orbital cysticercosis. Three patients with orbital cysticercosis (two extra-ocular, one ocular) were studied using multi-slice CT with thin coronal and sagittal reformations and 3D steady state MR (CISS 3D - Constructive Interference in Steady State) sequence.

Diffusion-weighted imaging and proton MR spectroscopy in the characterization of acute disseminated encephalomyelitis.

INTRODUCTION: Acute disseminated encephalomyelitis (ADEM) is usually a monophasic illness characterized by multiple lesions involving gray and white matter. Quantitative MR techniques were used to characterize and stage these lesions. METHODS: Eight patients (seven males and one female; mean age 19 years, range 5 to 36 years) were studied using conventional MRI (T2- and T1-weighted and FLAIR sequences), diffusion-weighted imaging (DWI) and proton magnetic resonance spectroscopy (MRS). Apparent diffusion coefficient (ADC) values and MRS ratios were calculated for the lesion and for normal-appearing white matter (NAWM). Three patients were imaged in the acute stage (within 7 days of the onset of neurological symptoms) and five in the subacute stage (after 7 days from the onset of symptoms). RESULTS: ADC values in NAWM were in the range 0.7-1.24 x 10(-3) mm/s2 (mean 0.937 +/- 0.17 mm/s2). ADC values of ADEM lesions in the acute stage were in the range 0.37-0.68 x 10(-3) mm/s2 (mean 0.56 +/- 0.16 mm/s2) and 1.01-1.31 x 10(-3) mm/s2 (mean 1.24 +/- 0.13 mm/s2) in the subacute stage. MRS ratios were obtained for all patients. NAA/Cho ratios were in the range 1.1-3.5 (mean 1.93 +/- 0.86) in the NAWM. NAA/Cho ratios within ADEM lesions in the acute stage were in the range 0.63-1.48 (mean 1.18 +/- 0.48) and 0.29-0.84 (mean 0.49 +/- 0.22) in the subacute stage. The ADC values, NAA/Cho and Cho/Cr ratios were significantly different between lesions in the acute and subacute stages (P < 0.001, P < 0.027, P < 0.047, respectively). ADC values were significantly different between lesions in the acute (P < 0.009) and subacute stages (P < 0.005) with NAWM. In addition, NAA/Cho and Cho/Cr ratios were significantly different between lesions in the subacute stage and NAWM (P < 0.006, P < 0.007, respectively). CONCLUSION: ADEM lesions were characterized in the acute stage by restricted diffusion and in the subacute stage by free diffusion and a decrease in NAA/Cho ratios. Restricted diffusion and progressive decrease in NAA/Cho ratios may help in staging the disease.

Disappearing saccular intracranial aneurysms: do they really disappear?

SUMMARY: Evolution and natural history of cerebral aneurysms is a dynamic process. Spontaneous regression in size or complete disappearance of an aneurysm is a known phenomenon, more commonly noted in giant intracranial aneurysms. However, reappearance or regrowth of such aneurysms is rare with few anecdotal reports. We report a series of four cases including one giant aneurysm, which either disappeared or regressed on sequential angiograms. Regrowth or reappearance of two of these previously disappeared or regressed aneurysms was noted and endovascularly treated while the other two cases are being followed up. The decision to follow up was crucial considering the nature of the aneurysms to change in morphology under the influence of various hemodynamic factors.

Middle meningeal arteriovenous fistula and its spontaneous closure. A case report and review of the literature.

SUMMARY: Middle meningeal artery pseudo-aneurysms and arteriovenous fistulas are usually post-traumatic, although occasional iatrogenic cases have been reported. The treatment has been obliteration of the fistula by surgical or endovascular means. Spontaneous closure of fistula is uncommon. We report a case of non-traumatic middle meningeal arteriovenous fistula in a patient with alcoholism, which resolved spontaneously without treatment.

MRI T(2) relaxometry of brain regions and cognitive dysfunction following electroconvulsive therapy.

BACKGROUND: Although electroconvulsive therapy (ECT) causes no structural brain damage, recent studies reported altered brain perfusion acutely following ECT. This is in keeping with brain edema which was noted in animal experiments following electroconvulsive shock. AIM: This study examined alteration in magnetic resonance imaging (MRI) T(2) relaxation time, a measure of brain edema, and its relation to therapeutic efficacy, orientation and memory impairment with ECT. MATERIALS AND METHODS: Fifteen drug-naive consenting patients of major depressive disorder with melancholia (DSM-IV) received ECT as first-line treatment. MRI scans were done before the first ECT and at 2 hours after the second ECT. T(2) relaxation time was measured bilaterally in thalamus, hippocampus, medial temporal lobes and dorsolateral frontal cortex by a blind rater. RESULTS: Depression scores and memory scores were reduced significantly both after the second and fifth ECT. There was no change in T(2) relaxation time after second ECT. CONCLUSION: The finding suggests that ECT does not produce demonstrable change acutely in brain parenchyma detectable by MRI scans.

MRI volumetric and 31P MRS metabolic correlates of caudate nucleus in antipsychotic-naïve schizophrenia.

OBJECTIVE: To examine the volumetric and metabolic correlates of caudate nucleus in antipsychotic-naïve schizophrenia patients in comparison with healthy controls. METHOD: Twelve antipsychotic-naïve schizophrenia patients and 13 healthy controls underwent (31)P magnetic resonance spectroscopy of basal ganglia. Magnetic resonance imaging volume of caudate nuclei was measured using scion image software. RESULTS: Patients had significantly smaller caudate volume than healthy controls. Phosphocreatine (PCr)/total phosphorous and PCr/total adenosine tri-phosphate ratios of both caudate nuclei were significantly lower in patients than controls. Significant negative correlation was found between the left caudate volume and left PCr/total phosphorus ratio in the patients. Age at onset of psychosis had i) significant negative correlation with right and left caudate volumes and ii) significant positive correlation with left PCr/total phosphorus ratio. CONCLUSION: The metabolic and volumetric abnormalities of caudate nucleus in antipsychotic-naïve schizophrenia patients support neurodevelopmental etiopathogenesis.

Altered structure and expression of RB1 gene and increased phosphorylation of pRb in human vestibular schwannomas.

Tumor-specific alterations at the RB1 gene locus in 30 human vestibular schwannomas including 10 NF2 and 20 sporadic cases were analysed. Southern blot analysis of DNA from these samples revealed loss of heterozygosity (LOH) at the RB1 locus in 6 of 24 informative cases (25%) compared to normal blood DNAs from the same patients. Northern blot analysis showed normal size RB1 mRNA in all the tumor samples. However, there was a 2-5-fold increase in the level of expression of the RB1 gene in all the tumor samples compared to the WI38 cell line which was used as control. Western blot analysis of the RB1 protein, pRb showed a 2.5-5-fold increase in the level of total pRb as compared to normal WI38 cell line. Sixty five to seventy five percent of the total pRb were in phosphorylated form in most tumors. The LOH at the RB1 gene locus suggests genetic instability in these patients. Further, increased levels of RB1 mRNA, total pRb and the phosphorylated form of pRb suggests that RB1 gene in these tumors may have anti-apoptotic function. These results suggest that the RB1 gene has a major role in the development of human vestibular schwannomas.

Basal ganglia high-energy phosphate metabolism in neuroleptic-naive patients with schizophrenia: a 31-phosphorus magnetic resonance spectroscopic study.

OBJECTIVE: This study used 31-phosphorus magnetic resonance spectroscopy ((31)P MRS) to investigate basal ganglia abnormalities in neuroleptic-naive patients with schizophrenia. METHOD: Nineteen schizophrenia patients and 31 age- and sex-matched healthy comparison subjects underwent (31)P MRS. RESULTS: The phosphocreatine/total phosphorus and phosphocreatine/total ATP ratios in both basal ganglia were significantly lower in patients. CONCLUSIONS: Schizophrenia patients showed features of increased metabolism in the basal ganglia consistent with impaired activity of the frontostriatal pathways.

Spectrum of epilepsy in tuberous sclerosis.

Tuberous sclerosis (TS) is an autosomal dominant disease that affects the brain, skin, eye, heart and kidney. The diagnostic criteria for tuberous sclerosis complex (TSC) have recently been revised. There are relatively few Indian studies on this disorder. Twenty-six patients diagnosed as having TS over a period of 18 years are being reported. The onset of seizures ranged from infancy to adolescence. The patterns of epilepsy encountered were generalized tonic clonic seizures (13), complex partial seizures (10), simple partial seizures (9) and myoclonic jerks (4) including infantile spasms (3). Patients often had more than one seizure type. Nineteen patients were mentally subnormal. Cutaneous manifestations were facial angiofibroma i.e. adenoma sebaceum (20), shagreen patches (7), hypopigmented macules (6), ash leaf spots (4), café-au-lait spots (2), facial hypoplasia (2) and periungual fibromas (1). One patient each had retinal phakoma and renal angiomyolipoma. CT scan revealed sub-ependymal calcifications (12), parenchymal tubers (3), cerebral edema (3) and cortical atrophy (1). One patient had enhancement of peri-ventricular sub-ependymal lesions on MRI. Anticonvulsants prescribed were phenobarbitone (20), diphenyl hydantoin (14), carbamazepine (8), sodium valproate (4), benzodiazepines (4), ACTH (2), prednisone (1), mysoline (1) and vigabatrin (1). Most patients were on combinations of anti-convulsants and response to therapy was usually not very satisfactory. However, the child treated with vigabatrin did well.