Visual grading system for vasospasm based on perfusion CT imaging: comparisons with conventional angiography and quantitative perfusion CT.

BACKGROUND: The purpose of this study was to compare simple visual grading of perfusion CT (PCT) maps to a more quantitative, threshold-based interpretation of PCT parameters in the characterization of presence and severity of vasospasm. METHODS: Thirty-three patients with acute subarachnoid hemorrhage were enrolled in a prospective study and underwent a total of 40 paired PCT and digital subtraction angiography (DSA) examinations. A neuroradiologist and a neurologist reviewed the PCT mean transit time (MTT), cerebral blood flow (CBF), and cerebral blood volume maps independently; they evaluated five anatomical regions (frontal, temporal, parietal, occipital/thalami, and basal ganglia/insula) and graded them for abnormality (0 if normal, 1 if abnormal in <50% of the region, and 2 if abnormal in >or=50% of the region). A third neuroradiologist blinded to the PCT results reviewed the DSA examinations and assessed 19 segments for the presence or absence of vasospasm. Correlation between PCT and DSA scores was assessed, as well as the sensitivity and specificity of PCT compared to DSA used as a gold standard. RESULTS: MTT (R(2) = 0.939) and CBF (R(2) = 0.907) scores correlated best with DSA scores (p < 0.001). MTT scoring had a sensitivity of 92% and a specificity of 86% compared to DSA; CBF scoring had a sensitivity of 75% and a specificity of 95%. The interobserver agreement between neuroradiologist and neurologist was found to have kappa = 0.789 for MTT and 0.658 for CBF. CONCLUSION: We propose a user-friendly visual grading system for PCT maps in patients with suspected vasospasm. This visual approach compares favorably to the results of DSA. Sensitive MTT maps should be used for screening, and specific CBF maps for confirmation of vasospasm.

Prospective evaluation of multidetector-row CT angiography for the diagnosis of vasospasm following subarachnoid hemorrhage: a comparison with digital subtraction angiography.

PURPOSE: To evaluate the accuracy of multidetector-row CT angiography (CTA) for the diagnosis of large-vessel vasospasm following subarachnoid hemorrhage by comparison to digital subtraction angiography (DSA). METHODS: Thirty-three patients with acute subarachnoid hemorrhage were enrolled in a prospective study and underwent a total of 40 CTA and DSA examinations within 24 h of each other. Two neuroradiologists reviewed the CTA examinations independently. A third neuroradiologist blinded to the CTA results reviewed the DSA examinations. In each patient, for both techniques, 23 arterial segments were evaluated for their degree of narrowing; the reviewers were asked to attribute every narrowing to 'vasospasm' or 'hypoplasia'. Agreement between CTA and DSA for the degree of narrowing, and agreement between the two CTA readers, were calculated using weighted kappa-coefficients. Sensitivity, specificity, accuracy, positive and negative predictive value (NPV) of CTA to detect large-vessel vasospasm were calculated considering DSA as the gold standard. RESULTS: Substantial correlation (kappa = 0.638) was found between CTA and DSA for the detection of arterial narrowing. Interobserver agreement between the two CTA reviewers for the degree of luminal narrowing was substantial (kappa = 0.712).CTA was 87% accurate for the diagnosis of large-vessel vasospasm; the NPV of CTA was 95%. CTA was more accurate, and interobserver agreement higher, for the proximal arterial segments (basilar and vertebral arteries) than for the distal ones (P2 segments). Using CTA as a screening modality, 83% of unnecessary DSA would have been avoided. CONCLUSION: Compared to the gold standard of DSA, CTA is accurate for the detection of large-vessel vasospasm, and has a very high NPV.

Rapid isolation of Mycobacteria--need of the hour in our settings.

BACKGROUND: To compare Bactec MGIT 960 with LJ media in terms of time taken for the initial isolation of mycobacteria. METHODS: A total of 100 AFB (acid fast bacillus) positive sputum samples were processed and inoculated in both the Lowenstein Jensen (LJ) media and mycobacterium growth indicator tube (MGIT) tubes. RESULTS: Of the 100 samples, positive growth was obtained from all the samples on both the MGIT and LJ media. In MGIT 53% samples grew in 4 days, 30% in 5 days and 17% in 6 days (Mean = 4.6 days) while on LJ media, 44% grew in 30 days, 20% in 35 days and 36% in 44 days (Mean = 37 days). Significant difference was observed between two systems with a p-value of less than 0.05. CONCLUSION: Bactec MGIT 960 is a much faster and efficient system for the initial isolation of mycobacteria.

Anti bacterial activity of Nigella sativa against clinical isolates of methicillin resistant Staphylococcus aureus.

BACKGROUND: Methicillin resistant Staphylococcus aureus (MRSA) continues to be one of the commonest pathogens encountered in clinical as well as laboratory practice. It has become a major health problem worldwide. Newer antimicrobials/agents are urgently needed to combat this problem MRSA resistance to various anti-staphylococcal agents. In the back-drop of this difficult situation Nigella sativa commonly known as black seed (ethanolic extract) was aimed at to evaluate if it had any anti-staphylococcal activity. METHODS: The extract was prepared by reflux extraction method. Disc diffusion and in agar dilution methods were performed to assess the antibacterial activity. Staphylococcus aureus ATCC 25923 was used as the standard reference strain. RESULTS: All tested strains of MRSA were sensitive to N. sativa extract at a concentration of 4 mg/disc while the extract had an MIC range of 0.2-0.5 mg/ml. CONCLUSION: The results indicated that N. sativa has inhibitory effect on MRSA. This finding warrants necessity of further investigation of this product of folk medicine.