Bit Error Rate (BER) Analysis of Conventional OFDM (DFT - OFDM) And Wavelet Based OFDM (DWT – OFDM)

OFDM has been widely adopted in many applications due to its good spectral performance and low sensitivity to impulse noise and multipath channels. In OFDM that a cyclic prefixes (CP) is appended to each symbol in order to mitigate the effect of Inter-Symbol-Interference (ISI) and intercarrier interference (ICI). However, this reduces the spectral efficiency. A perfect reconstruction using wavelet based OFDM provides good orthogonality and with its use Bit Error Rate is improved. Wavelet based system does not require CP, so spectrum efficiency is increased. In this paper, we are presenting BER analysis of conventional and wavelet based OFDM in LTE using different modulation techniques like QAM 2, QAM 4, QAM 16, QAM 256 and PSK. DOI: 10.17762/ijritcc2321-8169.15018

Surgery in multisegmental cervical spondylotic myelopathy: Outcome analysis in a series of 65 patients

Background: Multi-segmental cervical spondylotic myelopathy (MS-CSM) can be dealt with by either anterior or posterior approaches. The aim of study was to analyze the surgical outcomes of MS-CSM treated by either anterior cervical discectomy with fusion and cervical plating (ACDF) or cervical laminoplasty (LP). Materials and Methods: Sixty-five patients with MS-CSM (two or more levels) underwent either ACDF (n=13) or LP (n=52). ACDF was performed in patients having these criteria: (i) three or less levels involved, (ii) myeloradiculopathy, (iii) pre-dominant anterior compression radiologically, (iv) <50 years age. LP was chosen in: (i) more than three levels involved (ii) posterior compression radiologically, (iii) >50 years age. Patients were evaluated pre- and post-operatively on the basis of modified Japanese Orthopedic Association (mJOA) scoring and Hirabayashi formula. Thirty-five patients were followed up (8 in ACDF group and 27 in LP group). The mean follow-up period was 37.5 months (12.5-54 months). Results: The mean pre-operative mJOA score in the ACDF group and the LP group was 11±2.62 and 10.6±2.04, respectively. The mean final post-operative mJOA score in the ACDF group (n=8) in follow-up was 14.12±2.36 (P<0.05) and in the LP group (n=27) was 14.63±1.64 (P<0.05). 86% had good-to-excellent outcome while 8.5% had poor outcome. Overall, the mean recovery was 64.73±18.9%. On analyzing two groups separately, the mean recovery in the ACDF group was 59.62±24.2, while in the LP group was 66.25±17.3 (P<0.05). Conclusions: The choice of ACDF and LP in MS-CSM depends on pre-operative clinical and radiological parameters. If the surgical approach is chosen correctly, the surgery in MS-CSM can result in significant improvement in the clinical outcome of these patients

Extensive long-segment cervicothoracic traumatic spinal epidural hematoma with avulsion of C7, C8, and T1 nerve roots

Traumatic spinal epidural hematoma (TSEH) is of rare clinical occurrence. We report a case of a young man with posttraumatic long-segment spinal epidural hematoma. Evacuation of the hematoma led to complete neurologic recovery in our patient. Our case highlights the importance of early diagnosis and prompt surgical intervention for the evacuation of hematoma in preservation or maximum recovery of neurologic function. Imaging findings, management options, and the relevant literature are reviewed

Malignant hemangiopericytoma of pituitary fossa

Intracranial hemangiopericytomas are rare tumors with aggressive behavior. Other than the meninges, this lesion has rarely been reported in periventricular and sellar region. We report a case of malignant hemangiopericytoma in sellar region in a 47-year-old male who presented with history of sudden onset of bilateral visual disturbances. To best of our knowledge, this is the second case report of malignant hemangiopericytoma in this location. As this intracranial lesion shows aggressive behavior, in the form of recurrence or extracranial metastasis in comparison to its extracranial counterparts, diagnosis should be made cautiously

Stereotactic radiosurgery in hemangioblastoma: Experience over 14 years

Background: Although gamma knife has been advocated for hemangioblastomas, it is not used widely by neurosurgeons. Objective: We review our experience over 14 years in an attempt to define the role of stereotactic radiosurgery (SRS) in the management of hemangioblastomas. Patients and Methods: A retrospective study was conducted on all patients of hemangioblastoma who underwent SRS at our institute over a period of 14 years (1998–2011). Gamma knife plans, clinical history, and radiology were reviewed for all patients. Results: A total of 2767 patients underwent gamma knife during the study period. Of these, 10 (0.36%) patients were treated for 24 hemangioblastomas. Eight patients (80%) had von Hippel-Lindau disease while two had sporadic hemangioblastomas. The median peripheral dose (50% isodose) delivered to the tumors was 29.9 Gy. Clinical and radiological follow-up data were available for eight patients. Of these, two were re-operated for persisting cerebellar symptoms. The remaining six patients were recurrence-free at a mean follow-up of 48 months (range 19–108 months). One patient had an increase in cyst volume along with a decrease in the size of the mural nodule. Conclusions: SRS should be the first option for asymptomatic hemangioblastomas. Despite the obvious advantages, gamma knife is not widely used as an option for hemangioblastomas

Spinal teratomas: a clinico-pathological study of 27 patients

Background: Spinal cord teratomas are uncommon tumours. The diagnosis is rarely suspected before surgery and final diagnosis is invariably made at histopathological examination. Methods We retrospectively analysed our neuropathology records for the last 20 years and all patients diagnosed as spinal teratomas were retrieved. The clinical and radiological features were noted. Slides were reviewed and the diagnosis was confirmed. Findings: During a period of 20 years, we found 27 examples of spinal teratomas. There was a wide age range and 37.3% presented in adulthood. Male predominance was observed both in children as well as adults. The dorso-lumbar location was common in children as well as in adults but an intramedullary location, in association with a myelomeningocele and split cord malformation, was more common in children. Twenty one patients had associated features of spinal dysraphism. Of the six who were not associated with this, five were adult patients. Radiologically mixed solid and cystic morphology, fat signal and areas of calcification were seen in one third of patients. All tumours except one showed benign (mature) components. Interestingly, two lesions contained mature renal tissue: one exhibited pulmonary differentiation and one had Wilm's tumour as a component of the teratoma. In five patients the initial sections showed epidermis with skin adenexal structures and a diagnosis of dermoid cyst was suspected but serial sectioning revealed other teratomatous components. All patients were treated with surgical excision. Conclusion: Although there are no specific features on imaging, mixed solid and cystic morphology, fat signal and areas of calcification are helpful in the pre-operative diagnosis. Most of these lesions are diagnosed on histopathological examination after surgery and therefore thorough sampling and serial sectioning are mandatory to identify all components of the teratoma in order to avoid misdiagnosis