Visual acuity through Night Vision Goggles (NVGs): A comparative assessment between Gen 2++ and Gen 3 NVGs under different illumination conditions

Introduction: During night flying operations, Night Vision Goggles (NVGs) help the aircrew to visualize by intensifying lights reflected from an object. Night sky illumination and image intensification mechanism are the two important factors that affect visual acuity (VA) through NVG. Hence, assessment of visual acuity through Gen 2++ and Gen 3 NVG under different illumination conditions and comparative analysis between the two NVGs was the desired objective of the study. Material and Methods: In a prospective repetitive measure design, a total of 60 volunteered subjects were examined for their VA through Gen 2++ and Gen 3 NVGs using USAF Tri-Bar Chart in the eye lane room of the NVG Lab. The VA was measured under four different illumination conditions; full moon (FM), half moon (HF)quarter moon (QM), and starlight (SL) conditions. The measured VA was converted to logMAR values and analyzed. Results: VA deteriorated significantly with decreasing illuminations through both Gen 2++ (χ2 = 149.9, P < 0.001) and Gen 3 NVGs (χ2 = 156.5, P < 0.001). For Gen 2++ NVG, the difference in VA was statistically significant in all conditions other than between FM and HM. Whereas, it was almost significant for all illumination conditions for Gen 3 NVG. The VA through Gen 2++ was better than Gen 3 in all conditions and the difference in VA widened with decreasing illuminations. Conclusion: VA declined with decreasing illuminations for Gen 2++ as well as Gen 3 NVG, even though, the difference was not significant between FM and HM for Gen 2++ NVG. VA was observed to be consistently better through Gen 2++ NVG compared to Gen 3 across all four illumination conditions. However, keeping in view the dynamic changes in night sky illuminations during flying operations, the findings of the study need to be validated in operational conditions.

A Survey on Intensification Techniques used in Satellite Images

An image intensification is a required methodology in field of Satellite image research area. The images taken through satellite are captured from very longer distance and because of this images having garbling and noise as lots of airy barriers are present in between the path. The usage of Satellite images is very diverse in research areas like astrological studies, geographical studies, study of geoscience, etc. Nowadays, after taking a snapshot of an image, some of the radiometric or geometric based enhancement techniques are applied on the images taken from satellite but these techniques do not fulfill the requirements in all application areas. This is what there is a need to improvise the quality of an image before it is being actually used. The main objective behind this research work is to understand the different methodologies used in intensification of satellite images and how can we perform more improvements to existing techniques so these type of images which are taken from satellite are intelligible to the human eyes. The meaning of intensification in term of image is nothing but the altering of a look and feel of the image in a way that the information contained by that image is more readily intelligible visually.

Estimated cumulative X-ray exposure and additional cancer risk during the evaluation and treatment of scoliosis in children and young people requiring surgery

Introduction Clinicians and patients must weigh the benefits of radiological imaging against the risks of radiation exposure in the diagnosis and treatment of scoliosis. This report aims to estimate the cumulative absorbed and equivalent dose of radiation in patients undergoing surgical treatment for scoliosis, and to present this as an estimated risk of cancer compared to background radiation levels. Methods Retrospective review of estimated absorbed dose on the Computerised Radiology Information System (CRIS®). Patients undergoing surgical correction of scoliosis (age ≤ 25) from August 2010 to August 2015 investigated. Estimated absorbed dose [milligrays (mGy)] recorded. Pedicle screws inserted using image intensification. Equivalent dose [millisieverts (mSv)] and additional cancer risk calculated from the National Research Council document ‘Health risks from exposure to low levels of ionising radiation’ (2006). Results 271 patients identified. Mean age 15 (range 2–25). Mean total absorbed dose 2136 mGy [standard deviation (SD) 1700 mGy]. Mean number of plain spine radiographs was 8 (SD 3) with total 1884 mGy exposure (SD 1609 mGy). Additional dose provided by CT (mean 0.17 episodes), plain chest and abdominal radiographs and image intensification. Mean number of image intensification episodes was 1.1 with mean estimated exposure 180 mGy (SD 238 mGy). Image intensification accounted for 8% of the estimated absorbed dose during treatment. Estimated mean effective dose delivered was 20.952 mSv equating to an additional cancer risk of 0.27–0.45%. Conclusion Additional cancer risk from cumulative imaging is small and equivalent to approximately 8 years of natural background radiation. Use of image intensification for pedicle screw insertion is a minor contribution (8%) to the total patient dose.

Evaluation of Results of Closed Reamed Nailing for Diaphyseal Fracture of the Tibia-Experience of 35 cases

Introduction: Tibia is a subcutaneous bone and is more prone to trauma. Different treatment modalities exist for fracture shaft of the tibia. Intramedullary nailing in the treatment of fractures of the long bones was technically developed and popularized by Küntscher in the 1940’s. Treatment of tibial fracture in adult is a challenge to orthopedic surgeons due to poor soft tissue coverage and blood supply. Materials and methods: This study was prospective and interventional. This study was carried out in the private hospitals in Rajshahi over a period of 3 years. Total 35 patients with tibial shaft fracture were studied. Inclusion criteria were displaced closed diaphyseal fracture shaft of the Tibia, open fracture with Gustillo 1, 2 and 3A attended within 24 hours. Exclusion criteria were patient’s age below 16 years, grossly lacerated fracture, undisplaced fracture, patient unwilling to operate. Thirty three cases were operated within one week only two cases operated at 2 months due to angulations following conservative treatment. Open fracture was fixed within 24-48 hours. Broad spectrum antibiotic injectable Moxifloxacin was used in most of the cases for 2 doses then oral, Injectable Meropenem was used for the open fracture. Those patients suffering from G-3A fracture wound were covered by Hemisoleal flap Two weeks after primary surgery and were uneventful. In most of the cases image intensification was not used only three cases needed image intensification in case the fractures in lower ¼ th of the shaft to see the end of the Nail. Results: Two patients developed postoperative superficial wound infection which was recovered by regular dressing. Only one patient needed post-operative cast support because the fracture was comminuted. All patients started Knee bending from first post-operative day. Full range of knee movement was found in all patients. All fracture united properly within 12 weeks to 22 weeks with mean of 17 weeks. No cases of implant failure detected during the study period. Conclusion: The results of the current study reveal that the reamed interlocking nail in treatment of tibial diaphyseal fracture is safe, easy, successful and preferable method may be recommended as a stable fixation with early return to daily activities. TAJ 2019; 32(1): 9-16

Displaced Salter-Harris I fracture of the distal ulna physis

A 10-year-old girl presented to the emergency department having sustained a fall onto an outstretched left hand while playing soccer. Clinical and radiographical assessment identified a Salter-Harris I distal ulna fracture, as well as a buckle fracture of the distal radius. The injury was closed, and she had no neurovascular deficits on examination. She was brought to the operating theatre the following morning for closed reduction under general anaesthesia. Image intensification was used to confirm anatomical reduction, and an above-elbow moulded plaster-of-paris cast was applied. Follow-up clinical assessment at 6 weeks confirmed healing of the fracture, and she proceeded to make a full recovery. This case describes the anatomy and physiology of such rare injuries and outlines treatment principles and potential pitfalls based on best available evidence.