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British Journal of Radiology [journal]
- Percutaneous radiofrequency ablation of spinal osteoid osteoma under CT-guidance. [JOURNAL ARTICLE]
- Br J Radiol 2014 Apr 9.:20140003.
Objectives Osteoid osteoma accounts for approximately 10 to 12% of all benign bone tumors and 3% of all bone tumors. Spinal involvement appears in 10 to 25% of all cases. The purpose of this study was to evaluate the safety and efficacy of CT-guided radiofrequency ablation in the treatment of spinal OO's and report our experience. Methods Thirteen patients suffering of spinal osteoid osteoma and treated at the authors' institution using radiofrequency ablation under CT- guidance were retrospectively evaluated. The radiofrequency probe was introduced through a 11G Jamshidi needle and the lesion was heated at 900C for 6 minutes. Results All procedures were considered technically successful as the probe had CT proof of correct positioning. Eleven out of thirteen patients reported pain relief after RF ablation. In two cases, RF ablation was repeated one month after the first procedure. Pain relief was achieved in both cases after the second procedure. No recurrence was reported throughout the follow- up. No complications like skin burn, soft tissue haematoma, infection, vessel damage or neurological deficit were reported. Conclusions The current study demonstrates that CT-guided percutaneous RF ablation is a safe and effective method for the treatment of spinal osteoid osteomas. Advances in knowledge: The data of this study support the efficacy and safety of the recently applied CT-guided percutaneous RF ablation technique for the treatment of spinal osteoid osteoma.
- Radiofrequency Artifacts in Echo-planar Imaging Induced by two 1.5T MR Scanners in Close Proximity. [JOURNAL ARTICLE]
- Br J Radiol 2014 Apr 9.:20130773.
Objectives: The purpose of this study is to assess radiofrequency (RF) artifacts in Echo planar imaging (EPI) induced by two 1.5T MR scanners in close proximity, and find an effective method to correct them. Methods: Based on the intact shielding of rooms, experiments were performed by two MR scanners with similar center-frequencies. Phantom A (PA) was scanned in one scanner in EPI at different bandwidths (BWs). Simultaneously, phantom B was scanned in a fixed sequence for scanning with the other scanner. RF artifact gaps of PA, scanning time and the image signal-noise-ratio (SNR) were measured and recorded. Statistical analysis was performed with the repeated measures analysis of variance test. Based on findings obtained from PA, three healthy volunteers were studied at a conventional BW and a lower BW to observe the artifact variance. Results: EPI RF artifacts were symmetrically situated in both sides of the image following the phase-encoding direction. The gap size of artifact became larger and the SNR was significantly improved with a narrower BW. RF artifacts with a lower BW in volunteers presented the same characteristic as PA. Conclusions: For EPI RF artifacts produced by two 1.5T MR scanners with approximate center-frequencies, we can reduce BW in a suitable range to minimize the effect on MR imaging. Advances in knowledge: MR scanners with the same field strength installed in the vicinity might produce RF artifacts in the sequence at larger BW. Reducing BW properly is effective to control the position of artifacts and improve the image quality.
- How Often do Surgeons Intervene on Shoulder Labral Lesions detected at MR exam? A retrospective review of MR exams correlated with arthroscopy. [JOURNAL ARTICLE]
- Br J Radiol 2014 Apr 9.:20130736.
Objective. We report the prevalence of surgical intervention on shoulder labral lesions detected at MR examination and how surgeons describe labral tears in their arthroscopy reports. Methods and materials. A retrospective review of 100 consecutive patients age fifty or less who had shoulder labral tears on MR and went to surgery was performed.It was determined whether surgical intervention was performed on the MR lesions. Results. Of these one hundred patients, seventy-two had SLAP (superior labral anterior to posterior) tears , thirty eight had posterior labral tears and twenty eight had anterior labral tears on MR exam.All one hundred patients went on to arthroscopy. All lesions described on MR were described on arthroscopy. Of the seventy- two SLAP tears, fifty -one were debrided. The remaining eight SLAP tears were tacked surgically. Of the thirty- eight posterior labral tears, twenty-nine were debrided. Two had surgical tacking performed. Of the twenty- eight anterior labral tears described on MR exam, twenty- six had surgical tacking performed and two were debrided. There were nine additional labral tears seen on arthroscopy not seen on MR examination. Conclusions. In this series, a high percentage of SLAP tears and posterior labral tears described on MR examination did not have surgical tacking. Most anterior labral tears had surgical tacking. Based on the above, our surgeons request we describe superior and posterior labral lesions as fraying and /or tearing unless we can see a displaced tear. Advances in Knowledge MR imaging allows for sensitive detection of labral tears. The tears often are not clinically significant.
- Epipericardial Fat Necrosis: an Underdiagnosed Condition. [JOURNAL ARTICLE]
- Br J Radiol 2014 Apr 8.:20140118.
Objectives: Epipericardial fat necrosis is an uncommon benign and self-limited condition that leads patients to the emergency department due to the onset of acute pleuritic chest pain. The aim of this study was to describe the cases of this disease in our institution and to illustrate the associated clinical and radiological findings. Methods: We reviewed 3604 chest scans referred by the emergency department from November 2011 to July 2013. Patients diagnosed with epipericardial necrosis had their medical records and original tomography reports analyzed. Results: Chest pain was the primary complaint in 426 patients; 11 of them had definitive epipericardial fat necrosis findings characterized by a round soft tissue attenuation lesion with a varying degree of strands. All patients presented with pleuritic chest pain on the same side as the lesion. Pericardial thickening, pleural effusion and mild atelectasis were the associated tomography findings. Cardiac enzyme and d-dimer tests performed during the episode were normal in all cases. Only 27% of the cases were correctly diagnosed as epipericardial fat necrosis at the time of presentation. Conclusions: Epipericardial fat necrosis is a benign inflammatory condition frequently overlooked in the emergency department by physicians and radiologists but is an important factor in the differential diagnosis of patients with acute chest pain. Advances in knowledge: the manuscript adds clinical and radiological useful information about the condition and displays the importance of making this correct diagnosis to avoid uneccessary exams.
- Three-dimensional visualization of rat brain microvasculature following permanent focal ischemia by synchrotron radiation. [JOURNAL ARTICLE]
- Br J Radiol 2014 Apr 7.:20130670.
Objectives: Identifying morphological changes that occur in microvessels under both normal and ischemic conditions is crucial for understanding and treating stroke. However, conventional imaging techniques are not able to detect microvessels on a micron or sub-micron scale without angiography. In the present study, synchrotron radiation (SR)-based X-rays in-line phase contrast imaging (ILPCI) was used to acquire high resolution and high contrast images of rat brain tissues in both normal and ischemic states. Methods: ILPCI was performed at the Shanghai Synchrotron Radiation Facility without the use of contrast agents. Computed tomography (CT) slices were reformatted and then converted into three-dimensional reconstruction images to analyze subtle details of the cerebral microvascular network. Results: By using ILPCI, brain vessels up to 11.8 μm in diameter were resolved. The number of cortical and penetrating arteries detected were found to undergo a remarkable decrease within the infarct area. Three days after permanent ischemia, vascular masses were also observed in the peripheral region of the infarcts. Conclusions: SR-based ILPCI-CT can serve as a powerful tool to accurately visualize brain microvasculature. The morphological parameters of blood vessels in both CT slices and three-dimensional reconstructions were determined, and this approach has great potential for providing an effective diagnosis and evaluation for rehabilitation therapy for stroke. Advances in knowledge: In the absence of contrast agent, the three-dimensional morphology of the brain microvasculature in normal and stroke rats were obtained using SR-based ILPCI. SR imaging is a sensitive and promising method which can be used to explore primary brain function.
- Consistency of Response and Image Recognition, Pulmonary Nodules. [JOURNAL ARTICLE]
- Br J Radiol 2014 Apr 3.:20130767.
Objectives: To investigate the effect of recognition of a previously encountered radiograph on consistency of response in localising pulmonary nodules. Methods: Thirteen radiologists each interpreted 40 radiographs to locate pulmonary nodules. A few days later they again interpreted 40 radiographs. Half of the images in the second set were new. We asked the radiologists whether each image had been in the first set. We used Fisher's exact test and the Kruskal-Wallis test to evaluate the correlation between recognition of an image and consistency in its interpretation. We evaluated the data using all possible recognition levels - definitely, probably or possibly included versus definitely, probably or possibly not included, collapsing the recognition levels into two, and by eliminating the "possibly included" and "possibly not included" scores. Results: With all but one of six methods of looking at the data, there was no significant correlation between consistency in interpretation and recognition of the image. When the "possibly included" and "possibly not included" scores were eliminated, there was borderline statistical significance (p = 0.04) with slightly greater consistency in interpretation of recognised than non-recognised images. Conclusions: We found no convincing evidence that radiologists' recognition of images in an observer-performance study affects their interpretation on a second encounter. Advances in Knowledge: Conscious recognition of chest radiographs did not result in a greater degree of consistency in the tested interpretation as compared with interpretation of images that were not recognised.
- Topical application of sandal wood oil and turmeric based cream prevents radiodermatitis in head and neck cancer patients undergoing external beam radiotherapy: a pilot study. [JOURNAL ARTICLE]
- Br J Radiol 2014 Apr 2.:20130490.
Background: The study objective was to assess effectiveness of a turmeric and sandal oil [Vicco turmeric(r) cream (VTC)] containing on radiodermatitis in head and neck cancer patients undergoing radiotherapy. Methods: A total of fifty head and neck cancer patients requiring more than 60 Gy of curative radiotherapy/chemoradiotherapy were enrolled in the study. The volunteers were randomly divided in two groups of twenty five. Cohort one was assigned to topical application of Johnson's baby oil (JBO) and group two for VTC cream. Prophylactic application of cream was initiated on day 1 and was continued every day till two weeks after the end of treatment. The skin reactions were assessed weekly in accordance to RTOG scores by an investigator unaware of the details. Results: The incidence of radiodermatitis increased with exposure to radiation and was highest in both groups at week seven. However a significant reduction in grades of dermatitis were seen in cohorts applying VTC cream at all time points including two weeks post radiotherapy (p<0.015 to p<0.001). The occurrence of grade 3 dermatitis was lower in cohorts using VTC (p<0.01). Additionally, follow up observation two weeks after completion of radiotherapy also showed reduced degree of radiodermatitis in cohorts applying VTC (p=0.015). Conclusions: VTC is shown to be effective in prevention radiodermatitis and needs to be validated in larger double blind trials. Advances in Knowledge: For the first time, this study shows that the turmeric and sandal oil based cream was effective in preventing radiation-induced dermatitis.
- Towards a framework for analysis of eye-tracking studies in the three dimensional environment: a study of visual search by experienced readers of endoluminal CT colonography. [JOURNAL ARTICLE]
- Br J Radiol 2014 Mar 29.:20130614.
Objective: Eye tracking in three dimensions is novel, but established descriptors derived from two-dimensional (2D) studies are not transferable. We aimed to develop metrics suitable for statistical comparison of eye-tracking data obtained from readers of three-dimensional (3D) "virtual" medical imaging, using CT colonography (CTC) as a typical example. Methods: Ten experienced radiologists were eye tracked while observing eight 3D endoluminal CTC videos. Subsequently, we developed metrics that described their visual search patterns based on concepts derived from 2D gaze studies. Statistical methods were developed to allow analysis of the metrics. Results: Eye tracking was possible for all readers. Visual dwell on the moving region of interest (ROI) was defined as pursuit of the moving object across multiple frames. Using this concept of pursuit, five categories of metrics were defined that allowed characterization of reader gaze behaviour. These were time to first pursuit, identification and assessment time, pursuit duration, ROI size and pursuit frequency. Additional subcategories allowed us to further characterize visual search between readers in the test population. Conclusion: We propose metrics for the characterization of visual search of 3D moving medical images. These metrics can be used to compare readers' visual search patterns and provide a reproducible framework for the analysis of gaze tracking in the 3D environment. Advances in knowledge: This article describes a novel set of metrics that can be used to describe gaze behaviour when eye tracking readers during interpretation of 3D medical images. These metrics build on those established for 2D eye tracking and are applicable to increasingly common 3D medical image displays.
- Femoral neck shaft angle width is associated with hip-fracture risk in males but not independently of femoral neck bone density. [JOURNAL ARTICLE]
- Br J Radiol 2014 Mar 26.:20130358.
Objective: To investigate the specificity of the neck shaft angle (NSA) to predict hip fracture in males. Methods: We consecutively studied 228 males without fracture and 38 with hip fracture. A further 49 males with spine fracture were studied to evaluate the specificity of NSA for hip-fracture prediction. Femoral neck (FN) bone mineral density (FN-BMD), NSA, hip axis length and FN diameter (FND) were measured in each subject by dual X-ray absorptiometry. Between-mean differences in the studied variables were tested by the unpaired t-test. The ability of NSA to predict hip fracture was tested by logistic regression. Results: Compared with controls, FN-BMD (p < 0.01) was significantly lower in both groups of males with fractures, whereas FND (p < 0.01) and NSA (p = 0.05) were higher only in the hip-fracture group. A significant inverse correlation (p < 0.01) was found between NSA and FN-BMD. By age-, height- and weight-corrected logistic regression, none of the tested geometric parameters, separately considered from FN-BMD, entered the best model to predict spine fracture, whereas NSA (p < 0.03) predicted hip fracture together with age (p < 0.001). When forced into the regression, FN-BMD (p < 0.001) became the only fracture predictor to enter the best model to predict both fracture types. Conclusion: NSA is associated with hip-fracture risk in males but is not independent of FN-BMD. Advances in knowledge: The lack of ability of NSA to predict hip fracture in males independent of FN-BMD should depend on its inverse correlation with FN-BMD by capturing, as the strongest fracture predictor, some of the effects of NSA on the hip fracture. Conversely, NSA in females does not correlate with FN-BMD but independently predicts hip fractures.
- An investigation of the radiation doses to the lower legs and feet of staff undertaking interventional procedures. [JOURNAL ARTICLE]
- Br J Radiol 2014 Mar 28.:20130746.
Objectives: Occupational doses from fluoroscopic procedures are some of the highest amongst staff. Protective equipment and dose monitoring are used to minimise and control the risk. Other studies have considered the effectiveness of this protection but this further study considers whether the protection is adequate for the lower leg and foot and to what extent they can be reduced. Method: Scatter air kerma profiles at toe level were measured with an ionisation chamber. TLDs and lower extremity phantoms were used to estimate the dose variation with couch height. A seven week period of in situ toe dose monitoring of four radiologists was also undertaken. Results: Using protective curtains effectively reduced exposure to most of the lower extremity. Toe doses were found to be high and increased with couch height. In situ monitoring indicated annual toe doses of 110 mSv for two of the four radiologists monitored. Conclusion: Protective curtains should be used but they may have limitations with respect to toe dose. Annual toe doses approaching the classification threshold of 150 mSv were measured for two radiologists. Caution should be taken when there is a gap below the curtain and when possible staff should step back from the couch. The lower leg and toes should be included in local radiation protection programmes. Advances in knowledge: Toe doses in interventional radiology may be higher then thought and may require inclusion in radiation protection programmes.