Browsing by Author "Bodhey, Narendra K."
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Item Clinical applications of susceptibility weighted MR imaging of the brain - a pictorial review(NEURORADIOLOGY, 2008)Introduction Susceptibility-weighted imaging (SWI) is a novel magnetic resonance (MR) technique that exploits the magnetic susceptibility differences of various tissues, such as blood, iron and calcification. This pictorial review covers many clinical conditions illustrating its usefulness.Methods SWI consists of using both magnitude and phase images from a high-resolution, three-dimensional fully velocity-compensated gradient echo sequence. Phase mask is created from the MR phase images, and multiplying these with the magnitude images increase the conspicuity of the smaller veins and other sources of susceptibility effects, which is depicted using minimal intensity projection (minIP).Results The phase images are useful in differentiating between diamagnetic and paramagnetic susceptibility effects of calcium and blood, respectively. This unique MR sequence will help in detecting occult low flow vascular lesions, calcification and cerebral microbleed in various pathologic conditions and aids in characterizing tumors and degenerative diseases of the brain. This sequence also can be used to visualize normal brain structures with conspicuity.Conclusion Susceptibility-weighted imaging is useful in differentiating and characterizing diverse brain pathologies.Item Effect of 980-nm Diode Laser and 1064-nm Nd:YAG Laser on the Intervertebral Disc-In Vitro and in Vivo Studies(PHOTOMEDICINE AND LASER SURGERY, 2009)Objective: Our aim was to histologically evaluate the thermal changes in bovine intervertebral discs caused by 980-nm diode and 1064-nm Nd:YAG lasers. Further aims were to standardize the technique for in vivo animal research and to study its efficacy for clinical practice. Background: When conservative methods fail, surgery has so far been the only measure for severe back pain due to disc prolapse and herniation. Recently, the minimally invasive technique of laser disc decompression has become more popular because it has advantages over open surgery in properly selected cases. Methods: In vitro studies were done with Nd: YAG and diode lasers ( 1064 and 980 nm, respectively) on bovine intervertebral discs using a bare fiber tip or a focusing lens attached to a fiber tip. These studies were followed by in vivo studies in a canine model using a Nd: YAG laser with a bare fiber tip. Autopsies were done immediately and at 3, 6, 9, and 12mo after ablation and the histopathology of excised discs was evaluated. Results: Depending upon the depth of ablation and the intensity of charring and carbonization, a standardized energy density and pulse duration were identified. Conclusion: Nd: YAG laser with initial delivery of 40-W laser power and a reduced power of 10-15W thereafter, delivering a total energy density of 1500 2000J/cm(2) using a bare fiber tip, is recommended for clinical applications.Item Endovascular treatment of direct carotid cavernous fistulae: a pictorial review(NEURORADIOLOGY, 2006)Introduction Direct carotid-cavernous fistulae (CCFs) are type A fistulae according to Barrow's classification. Endovascular treatment of these lesions is challenging.Methods The purpose of this review was to evaluate the endovascular treatment of direct CCFs. We also describe the technique, symptomatology and complications associated with the procedure and report on the long-term follow-up in our treated patients.Results A total of 89 patients with a direct CCF were treated. All patients had baseline brain CT or MR imaging. Treatment comprised transarterial balloon or coil embolizations. The patients were followed up at 1 month and then every 6 months thereafter. Detachable balloons were used in 79 fistulae. In 12 fistulae the balloon could not be negotiated through the fistula and these fistulae were treated with transarterial coil occlusion. Clinical outcomes of the treated patients evaluated at 1 month were: 79 patients (88.8%) cured, 9 (10.1%) significantly improved, 1 (1.1%) remaining static.Conclusion Endovascular treatment of direct CCFs is safe and effective and results in long-term cure.Item Imaging features in Hirayama disease(NEUROLOGY INDIA, 2008)Purpose: To evaluate the MR findings in clinically suspected cases of Hirayama disease. Materials and Methods: The pre and post contrast neutral and flexion position cervical MR images of eight patients of clinically suspected Hirayama disease were evaluated for the following findings: localized lower cervical cord atrophy, asymmetric cord flattening, abnormal cervical curvature, loss of attachment between the posterior dural sac and subjacent lamina, anterior shifting of the posterior wall of the cervical dural canal and enhancing epidural component with flow voids. The distribution of the above features in our patient population was noted and correlated with their clinical presentation and electromyography findings. Observations: Although lower cervical cord atrophy was noted in all eight cases of suspected Hirayama disease, the rest of the findings were variably distributed with asymmetric cord flattening, abnormal cervical curvature, anterior shifting of the posterior wall of the cervical dural canal and enhancing epidural component seen in six out of eight (75%) cases. An additional finding of thoracic extension of the enhancing epidural component was also noted in five out of eight cases. Conclusion: Dynamic post contrast MRI evaluation of cervicothoracic spine is an accurate method for the diagnosis of Hirayama disease.Item Percutaneous laser disc decompression: Clinical experience at SCTIMST and long term follow up(NEUROLOGY INDIA, 2006)Background: Low backache (LBA) is now increasing in younger population due to misdirected spinal kinetics secondary to improper posture, heavy load lifting and motorbike driving. Hence minimally invasive procedures are increasingly sought after. Among these, PLDD is currently popular and in use. We present our long term follow-up in the use of Nd:YAG laser for PLDD. Aim: To herniation of lumbar discs & long term follow up results. Materials and Methods: Forty patients with contained lumbar disc herniation on MRI and who did not respond to 6 weeks conservative treatment were subjected to PLDD. L4-5 disc was treated in 31, L5-S1 in 12 and L1-2 and L3-4 in one each. Nd:YAG laser at 1064 nm was used for the procedure. Total laser energy of 1500-2000 Joules was delivered at the disc space depending upon the size. Results: There was immediate pain relief in 32/40 (80%). According to MacNab criteria good to fair response was seen in 37/40 (92%) and 3 patients (7.5%) responded poorly to this treatment. On follow up which ranged from 1 to 7 years, 34/40 (85%) had pain relief with no need for further treatment. Complications: Significant pain at local puncture site was experienced by 8 (20%), pain during lasing was experienced by one. One patient developed muscular spasm. Conclusion: Percutaneous laser disc decompression is a safe, relatively noninvasive and effective treatment modality for contained, nonsequestered, herniated lumbar disc disease in carefully selected patients.Item Retroperitoneal hematoma: An unusual complication after femoral vein cannulation(JOURNAL OF CARDIOTHORACIC AND VASCULAR ANESTHESIA, 2006)