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Objective Aim of this study is to evaluate the effect of craniospinal interventions on cerebrospinal fluid (CSF) flow hydrodynamics and study the correlation of postoperative changes in flow alteration with clinical outcome. Materials and Methods Fifty patients who underwent various craniospinal procedures were studied using conventional and phase-contrast magnetic resonance imaging (PCMRI) protocol. CSF flow quantification was performed at cerebral aqueduct, foramen magnum, C2–3, and D12–L1 vertebral levels with site showing maximal alteration of CSF flow dynamics considered as the region of interest. Velocity encoding was kept at 20 cm/s. Patients with pathology atcraniovertebral junction were considered separately (group I) from others (group II) due to different flow dynamics. Follow-up scans were performed after an interval of 1 month for temporal evaluation of changes in CSF flow dynamics. Results Patients in both groups showed a significant change in peak CSF velocity postoperatively (mean change of 1.34 cm/s in group I and 0.28 cm/s in group II) with bidirectional improvement in flow on cine-phase-contrast qualitative images. Regional pain (82%) and headache (46%) were seen in most of the patients preoperatively. Postoperatively clinical symptoms improved in 59.5%, static in 26.2%, and worsened in 14.3%. In both the groups, an improvement in clinical symptomatology had significant correlation with mean changes in peak CSF velocity postoperatively (p = 0.04 in both groups). Conclusion PCMRI can effectively evaluate changes in CSF flow noninvasively both pre- and postoperatively. This may have potential role in determining clinical outcome and prognosis of patients undergoing procedures in craniospinal axis.

Introduction: The popliteal artery branching pattern has multiple variations which have implications in outcomes of various surgical procedures. Amongst cadaveric, Computed Tomography (CT) angiographic and Digital Subtraction Angiographic (DSA) studies, Multidetector Computed Tomography (MDCT) Angiography provides a comprehensive, quick and efficient evaluation of the popliteal arterial anatomy along with surrounding structures and related pathologies of the vascular and non-vascular structures. Aim: To evaluate the patterns of popliteal artery division on MDCT angiography of lower limb in patients presenting to a tertiary medical institute in Northern India. Materials and Methods: This retrospective descriptive study was conducted in Department of Radiology at Shri Guru Ram Rai Institute of Medical and Health Sciences, Dehradun, Uttarakhand, India (tertiary care medical institute of Northern India). Patients presenting for a period of one year from April 2021 to March 2022 were included in the study. The MDCT angiographic findings of 152 patients who were evaluated for various illness including peripheral vascular disease, popliteal arterial aneurysms and trauma were analysed. The branching pattern of popliteal artery was evaluated according to the classification system provided by Kim DU et al., Morphometric analysis of popliteal artery including diameter was also done. The imaging based data was collected and analysed by two radiologists. Chi-square test was used for statistical analysis. Results: The mean age of the patients was 54.18 years with males predominance of 110 (72.37%). Amongst the 304 limbs available for evaluation, the data from six limbs could not be assessed due to atherosclerotic blockage in four patients, extensive calcification in one patient and amputation in one patient. Hence, 298 limbs were evaluated on MDCT angiography for the pattern of branching of popliteal artery. Type IA was the most common pattern of division seen in 268 limbs (89.93%). Out of 298, 30 limbs showed variant anatomy, with unilateral variation in 18 patients and bilateral variation in six patients. Type III pattern (n=12, 4.03%) was more common than Type II pattern (n=11, 3.6%) in the study group. Conclusion: The knowledge of variations of popliteal arterial division and meticulous evaluation is essential to provide a successful roadmap for therapeutic measures.

Introduction: Cerebral Microbleeds (CMBs) are increasingly recognised as an important predictor of small vessel disease and cannot be detected on routine Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) sequences. Aim: CMBs on MRI and to compare the sensitivity of Susceptibility Weighted Imaging (SWI) and T2* Gradient Recalled Echo (GRE) sequences in detection of these microbleeds. Also, to evaluate association between topography (size, number and location) of CMBs and various risk factors. Materials and Methods: This Prospective Observational analytical study comprised of 67 patients with CMBs who were evaluated with Siemens 1.5 Tesla MRI machine. T2*-weighted GRE sequence and SWI were taken in all the patients in addition to routine MRI sequences. Two observers blinded to clinical information, independently interpreted the T2*GRE and SWI sequences. Both observers recorded the topographical details of CMBs which included presence, number, size and location and their association with various risk factors (hypertension, diabetes, smoking and hyperlipidemia). Inter-rater agreement for the number of CMBs on SWI and T2*GRE was calculated using Cohen’s Kappa (κ) as measure of agreement. Intra-Class Correlation Coefficient (ICC) for reliability index in test-retest, intra-rater and inter-rater reliability was also analysed. The intra-rater reliabilities of each rater were compared. The correlations between CMBs and risk factors was performed with Pearson’s correlation Coefficient (r). The p-value

Objective: The objective of the study was to evaluate the cerebrospinal fluid (CSF) flow alterations in meningitis using phase-contrast magnetic resonance imaging (PCMRI). Materials and Methods: Fifty patients with clinically confirmed or strongly suspected infectious meningitis and 20 controls were evaluated with MRI. Quantitative CSF analysis was performed at the level of cerebral aqueduct using cardiac-gated PCMRI. Velocity encoding (Venc) was kept at 20 cm/s. Patients were subdivided into Group I (patients with hydrocephalus [n = 21]) and Group II (patients without hydrocephalus [n = 29]). Results: The mean peak velocity and stroke volume in controls were 2.49 ± 0.86 cm/s and 13.23 ± 6.84 µl and in patients were 2.85 ± 2.90 cm/s and 16.30 ± 20.02 µl, respectively. A wide variation of flow parameters was noted in meningitis irrespective of the degree of ventricular dilatation. A significant difference in peak velocity and stroke volume was noted in Group II as compared to controls. Viral meningitis showed milder alteration of CSF flow dynamics as compared to bacterial and tuberculous etiologies. At a cutoff value of 3.57 cm/s in peak CSF velocity, the specificity was 100% and sensitivity was 22.7% to differentiate between viral and non-viral meningitis. Conclusion: Alteration of CSF flow dynamics on PCMRI can improve segregation of patients into viral and non- viral etiologies, especially in those in whom contrast is contraindicated or not recommended. This may aid in institution of appropriate clinical treatment.

Introduction: Vocal Cord Palsy (VCP) is a common clinical presentation and must be considered as a sign of underlying disease, rather than simply a diagnosis unto itself. Despite of idiopathic causes in nearly half of the cases, imaging studies are still indispensible for evaluating the varied aetiologies. Most of the signs of VCP are clearly demonstrable on axial Computed Tomography (CT) sections except one i.e., flattening of ipsilateral subglottic arch which needs specific evaluation only on coronal reformatted images. The diagnostic value of this sign is still debatable. Aim: To evaluate any additional advantage offered by coronal reformatted images in cases of unilateral VCP especially those with confusing/equivocal findings and to find out most reliable signs of unilateral VCP on axial CT sections. Materials and Methods: This retrospective study comprised of patients with clinical suspicion of VCP who were referred for CT neck and thorax in Department of Radiology at tertiary care hospital in the previous 36 months (July 2014 to June 2017). Only the cases with laryngoscopically confirmed unilateral VCP were included. The cases with laryngeal malignancy were excluded. Various imaging signs of unilateral VCP were evaluated on both axial and coronal reformatted images. Spearman’s rho (ρ) correlation coefficient was calculated to assess correlation between most frequent signs of unilateral VCP individually and also with flattening of ipsilateral subglottic arch (evaluated on coronal reformatted images). Results: Thickening and medialisation of ipsilateral aryepiglottic fold was uniformly present in all the cases of unilateral VCP. Two other most frequent signs which correlated strongly with unilateral VCP were dilatation of ipsilateral laryngeal ventricle (n=29, 93.5%) and dilatation of ipsilateral pyriform sinus (n=27, 87%). Flattening of ipsilateral subglottic arch on coronal reformatted images was seen in only 26% patients. This sign was absent in all four cases with equivocal and contralateral findings in present study. Conclusion: The coronal reformatted images failed to demonstrate any additional advantage over axial sections in diagnosing unilateral VCP even in equivocal or difficult cases. The thickening and medialisation of ipsilateral aryepiglottic fold on routine axial CT images is probably the most reliable and consistent sign for diagnosing unilateral VCP with dilatation of ipsilateral laryngeal ventricle and ipsilateral pyriform sinus as two other major supportive signs.

Introduction: Differentiating calcification from chronic microbleeds on imaging may have important clinical implications. Aim: The present study aimed to evaluate the role and relative advantages of Magnetic Resonance Imaging (MRI) in the detection and differentiation of intracranial calcifications and chronic microbleeds. Materials and Methods: The retrospective study comprised of 100 patients having either intracranial calcifications or microhaemorrhages selected on the basis of Computerized Tomography (CT) and MRI using predefined criteria. Two independent blinded observers evaluated the images qualitatively and quantitatively. Single pixel values were taken in the circular Region of Interest (ROI) on magnitude SWI, phase Susceptibility Weighted Imaging (SWI) and Diffusion Weighted Imaging (DWI) for quantitative analysis. Results: Fifty patients with 76 focal calcifications and another 50 patients with 245 chronic microbleeds formed part of the study. Overall sensitivity of SWI in detection of calcification was 93.9% with good inter observer agreeability (k= 0.7) on phase SWI. All the chronic microbleeds were seen on SWI but there was only moderate inter observer agreeability in evaluation of signal on phase component (k= 0.5). Average pixel values of calcifications and chronic microbleeds were -312.5±187 SD and 541.9±301.7 SD respectively on phase SWI, (p=0.0001

Dysembryoplastic neuroepithelial tumor (DNET) is a mixed glioneuronal tumour which is most commonly seen in the temporal lobe of children and young adults. The patients present with pharmacoresistant complex partial seizures. DNET closely resembles oligodendroglioma clinicopathologically but immunohistochemistry, with positivity of NeuN in neurons and small round cells, aids in the differential diagnosis, which is important as DNET has a better prognosis. We report a case of DNET in a 16 year old female who presented with complex partial seizures and a mass in the right frontal cortex.

Objective: To qualitatively and quantitatively differentiate leptomeningeal and vascular enhancement on Post-contrast Fluid Attenuated Inversion Recovery (PCFLAIR) sequence compared to post-contrast T1-weighted (PCT1W) sequence with fat suppression (FS) and evaluate its role in early detection of infectious meningitis. Materials and Methods: Thirty-one patients with diagnosis of meningitis were evaluated with pre and post-contrast FLAIR and T1-weighted sequences with fat suppression (FS). Qualitative assessment was done by two observers for presence, absence or equivocal status of leptomeningeal enhancement. Further, quantitative estimation of single pixel signal intensities (SPSI) for meningeal and vascular enhancement was undertaken. A statistical comparison was performed using Kappa coefficient and t-test. Results: The overall qualitative accuracy was 90.3% for PCFLAIR compared to 54.8% for PCT1W with FS sequence. PCFLAIR was found to be 100% accurate in the detection of tubercular and pyogenic meningitis and 70% accurate in the detection of viral meningitis while PCT1W with FS sequence showed the corresponding accuracy to be 76.2% and 0% respectively. Both observers rated PCFLAIR images better than PCT1W with FS at detecting meningitis (p

Objective To compare the contrast-enhanced fluid-attenuated inversion recovery (CE-FLAIR), the CE T1-weighted (CE-T1W) sequence with fat suppression (FS) and magnetization transfer (MT) for early detection and characterization of infectious meningitis. Materials and Methods Fifty patients and 10 control subjects were evaluated with the CE-FLAIR and the CE-T1W sequences with FS and MT. Qualitative assessment was done by two observers for presence and grading of abnormal leptomeningeal enhancement. Quantitative assessment included computation of net meningeal enhancement, using single pixel signal intensity software. A newly devised FLAIR based scoring system, based on certain imaging features including ventricular dilatation, ependymal enhancement, infarcts and subdural effusions was used to indicate the etiology. Data were analysed using the Student's t test, Cohen's Kappa coefficient, Pearson's correlation coefficient, the intraclass correlation coefficient, one way analysis of variance, and Fisher's exact test with Bonferroni correction as the post hoc test. Results The CE-FLAIR sequence demonstrated a better sensitivity (100%), diagnostic accuracy (95%), and a stronger correlation with the cerebrospinal fluid, total leukocyte count (r = 0.75), protein (r = 0.77), adenosine deaminase (r = 0.81) and blood glucose (r = -0.6) values compared to the CE-T1W sequences. Qualitative grades and quantitative meningeal enhancement on the CE-FLAIR sequence were also significantly greater than those on the other sequences. The FLAIR based scoring system yielded a diagnostic accuracy of 91.6% and a sensitivity of 96%. A strong inverse Pearson's correlation (r = -0.95) was found between the assigned score and patient's Glasgow Coma Scale at the time of admission. Conclusion The CE-FLAIR sequence is better suited for evaluating infectious meningitis and could be included as a part of the routine MR imaging protocol.

Objective: To validate the additional merits of two-dimensional (2D) single thick-slice Magnetic Resonance Myelography (MRM) in spinal imaging. Materials and Methods: 2D single thick-slice MRM was performed using T2 half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence in addition to routine Magnetic resonance (MR) sequences for spine in 220 patients. The images were evaluated for additional diagnostic information in spinal and extra-spinal regions. A three-point grading system was adopted depending upon the utility of MRM in contributing to the detection of spinal or extra-spinal findings. Grade 1 represented no contribution of MRM while grade 3 would indicate that it was essential to detection of findings. Results: Utility of MRM in spine was categorized as grade 3 in 10.9% cases (24/220), grade 2 in 21.8% (48/220) cases and grade 1 in 67.3% cases (148/220). Thus, the overall additional merit of MRM in spine was seen in 32.7% (72/220) of cases. Besides in 14.1% cases (31/220) extra-spinal pathologies were identified. Conclusion: 2D single thick-slice MRM could have additional merits in spinal imaging when used as an adjunct to routine MR sequences.

Pilomyxoid astrocytoma (PMA) is a recently described brain tumor. PMA shares similar features with pilocytic astrocytoma (PA), the most common central nervous system (CNS) tumor in the pediatric population, yet displays subtle histologic differences. We describe a case of PMA in a six-year-old male involving sellar and suprasellar region presenting with failure to thrive and delayed developmental milestones. The histological findings revealed a tumor composed of a monotonous population of loosely arranged cells with delicate piloid like processes, within a prominent myxoid background. The tumor lacked biphasic appearance, Rosenthal fibers, eosinophilic granular bodies and calcification that are commonly observed in classical PA. Previous studies have shown PMA to behave more aggressively than PA, with shorter progression-free survival as well as a higher rate of recurrence and CNS dissemination. Thus, recognition of PMA and its distinction from classical PA is very important.