Browsing by Author "Muthusami, P"

Now showing 1 - 5 of 5
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    Diffusion Tensor Imaging and Tractography of the Human Language Pathways: Moving Into the Clinical Realm
    (JOURNAL OF MAGNETIC RESONANCE IMAGING, 2014) Muthusami, P; James, J; Thomas, B; Kapilamoorthy, TR; Kesavadas, C
    The functional correlates of anatomical derangements are of interest to the neurological clinician. Diffusion tensor tractography (DTT) is a relatively new tool in the arsenal of functional neuroimaging, by which to assess white matter tracts in the brain. While much import has been given to tracking corticospinal tracts in neurological disease, studying language pathway interconnections using DTT has largely remained in the research realm. Hardware and software advances have allowed this tool to ease into clinical practice, with several radiologists, neurologists, and neurosurgeons now familiar with its applications. DTT images, although visually appealing, are founded in mathematical equations and assumptions, and require a more than basic understanding of principles and limitations before they can be integrated into routine clinical practice. Cognitive pathways like that of language, that are normally hard to assess and especially more so when pathologically affected, have been at the receiving end of several opposing and often controversial hypotheses, and the past decade has seen the clarification, validation or rejection of several of these by the in vivo charting of functional connectivity using DTT. The focus of this review is to illustrate DTT of the language pathways with emphasis on practical considerations, clinical applications, and limitations.
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    Glioma progression as revealed by diffusion tensor metrics
    (NEUROLOGY INDIA, 2012) Muthusami, P; Basti, RS; Thomas, B; Kapilamoorthy, TR; Kesavadas, C
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    Implicating the long styloid process in cervical carotid artery dissection
    (Neuroradiology., 2013-06) Muthusami, P; Kesavadas, C; Sylaja, PN; Thomas, B; Harsha, KJ; Kapilamoorthy, TR
    INTRODUCTION: To look for the presence and strength of association of cervical carotid artery dissection (CCAD) with a long styloid process. METHODS: This case-control analysis included 35 patients with 37 affected carotid arteries. CT angiograms of these patients were analyzed by two raters blinded to clinical and radiological diagnosis. Parameters assessed were styloid process length, its proximity to the cervical internal carotid artery, and its medial and anterior angulations. The same parameters were assessed in 70 CT angiograms in age and sex matched controls. RESULTS: Interrater correlations were 0.87, 0.40, 0.71, and 0.79 for styloid process length, contact distance, medial angulation, and anterior angulation, respectively. The mean styloid process length on the affected side was significantly more than on the contralateral side (37.8 vs. 34.6 mm, p = 0.006). There were also significant length and contact distance differences between the styloid processes ipsilateral to dissection and ipsilateral styloid processes of controls (38.9 vs. 36.2 mm, p = 0.05 and 3.1 vs. 5.0 mm, p = 0.05, respectively). There were increasing odds ratios (OR) for dissection with increasing styloid process length, with OR of 4.36 (95 % CI = 1.04 to 18.4, p = 0.04) for length more than 50 mm. ORs for dissection increased with decreasing contact distance, with OR for distances less than 5 mm being 7.58 (95 % CI = 0.93 to 62.1, p = 0.06). There was no significant association of CCAD with angulation of the styloid process. CONCLUSION: Length and contact distance of the styloid process are risk factors for CCAD, suggesting mechanical impingement.
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    Need for a nomogram of renal sizes in the Indian population-findings from a single centre sonographic study
    (INDIAN JOURNAL OF MEDICAL RESEARCH, 2014) Muthusami, P; Ananthakrishnan, R; Santosh, P
    Background & objectives: Renal size is an important parameter used in the diagnosis and follow up of renal diseases. However, while making decisions, clinicians must be aware of the dependence of these dimensions on the ethnicity of the individual, independent of anthropometric indices. There is no established nomogram for renal sizes in the Indian population. The aim of this study was to assess the applicability of oft-quoted ranges of normal renal sizes in our population. Methods: Renal dimensions including length, width and parenchymal thickness were sonographically measured in 140 individuals with no renal disease. Analysis was done for differences due to age, gender and laterality. The correlation of renal dimensions with anthropometric parameters like weight, height, body mass index (BMI) and body surface area (BSA) was analyzed. Results: The means of length, width and parenchymal thickness of all 280 kidneys of 140 patients were 9.65 +/- 0.63, 4.5 +/- 0.42 and 2.04 +/- 0.2 cm, respectively. There was a significant difference in parenchymal thickness between the right and left kidneys, while there was no significant right-left difference in length or width. Gender-wise analysis showed significant differences between male and female renal breadths but not length and parenchymal thickness. Age group-wise analysis showed significant decrease in renal length and parenchymal thickness beyond the seventh decade. There was a moderate positive correlation of bilateral renal length with body weight and BSA, and a weak positive correlation with body height and BMI. Interpretation & conclusions: Renal sizes in our population are in contrast to commonly quoted normal values in literature. Conclusions about renal sizes need to be made with reference to nomograms and should not be based upon data from other populations. We also present formulae whereby to derive renal sizes from anthropometric indices in our population.
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    The Role of Static Magnetic Resonance Urography in the Evaluation of Obstructive Uropathy
    (UROLOGY, 2013) Muthusami, P; Bhuvaneswari, V; Elangovan, S; Dorairajan, LN; Ramesh, A
    OBJECTIVE To assess the diagnostic accuracy of static magnetic resonance urography (MRU) in hydronephrosis and to compare parameters of hydronephrosis in MRU with intravenous urography (IVU). MATERIALS AND METHODS Sixty-nine patients were included in this study of which 55 patients with a total of 63 hydronephrotic units underwent both IVU and MRU. MRU was performed on a 1.5 T scanner using heavily T2-weighted sequences. The level, grade, and cause of obstruction on each modality were interpreted by 2 radiologists. These were compared with the final diagnosis based on other appropriate modalities including imaging, intraoperative and histopathologic diagnosis. RESULTS The sensitivity and specificity MRU in detecting hydronephrosis were 95% and 100%, respectively. In determining the level of obstruction, the strength of agreement between IVU and MRU using kappa statistics was kappa = 0.66, which corresponds to a good level of agreement. The Spearman correlation coefficient for the grade of hydronephrosis on MRU and IVU was 0.92 (95% confidence interval 0.86-0.95), with a P value of <.0001. The correct diagnosis was made in 89.2% of the cases by IVU and in 93.8% of the cases by MRU. CONCLUSION Along with a high sensitivity and specificity in detecting the presence, level, and grade of hydronephrosis, MRU without contrast also shows a good agreement with IVU. Static MRU can reliably replace IVU when the latter is contraindicated or technically difficult. UROLOGY 81: 623-628, 2013. (c) 2013 Elsevier Inc.