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British Journal of Radiology [journal]
- Ability of 18-fludeoxyglucose positron emission tomography/CT to detect incidental cancer. [JOURNAL ARTICLE]
- Br J Radiol 2014 Aug 13.:20140030.
Objective: To determine the prevalence and clinical features of pathologically-proven incidental cancer (IC) detected by whole-body 18-fludeoxyglucose ((18)F-FDG) positron emission tomography (PET)/CT, as well as the incidence of false positive and false negative results. Methods: We retrospectively reviewed reports derived from (18)F-FDG PET/CT images of 3,079 consecutive patients with known or suspected malignancies for three years. Discrete focal uptake indicating IC was identified from reports as well as pathological or clinical diagnoses and the clinical courses were investigated. False positive result was defined as uptake indicating IC, but not pathologically confirmed as malignant during follow-up. False negative result was defined as pathologically-proven IC detected by another modality at initial clinical workup, or diagnosed during follow-up period. Results: We found (18)F-FDG uptake indicating IC in 6.7 % of all patients and IC was pathologically proven in 2.2 %. The most common sites were the colon, lung, and stomach. The median survival duration of patients with IC was 42.0 months. The results were false positive in 4.5 % of all patients, and the results were false negative in 2.3 % of all patients. Conclusion: (18)F-FDG PET/CT is a valuable tool for detecting IC. The rate of false positive results and false-negative results are within acceptable range. Advances in knowledge: This is the first report to describe the survival of patients with IC, and the detailed features of false negative results at actual clinical settings.
- Development of an applicator for eye lens dosimetry during radiotherapy. [JOURNAL ARTICLE]
- Br J Radiol 2014 Aug 11.:20140311.
Objectives: To develop an applicator for in-vivo measurements of lens dose during radiotherapy Methods: A contact lens-shaped applicator made of acrylic was developed for in-vivo measurements of lens dose. This lens applicator allows the insertion of commercially available MOSFET dosimeters. CT images of an anthropomorphic phantom with and without the applicator were acquired. Each 10 VMAT plans for brain, and head and neck cancer were generated and delivered to an anthropomorphic phantom. The differences between the measured and the calculated doses at the lens applicator, as well as the differences between the measured and the calculated doses at the surface of the eyelid were acquired. Results: The average difference between the measured and the calculated dose with the applicator was 3.1 ± 1.8 cGy with a micro MOSFET and 2.8 ± 1.3 cGy with a standard MOSFET. The average difference without the lens applicator was 4.8 cGy ± 5.2 cGy with micro MOSFET and 5.7 ± 6.5 cGy with standard MOSFET. The maximum difference with micro MOSFET was 10.5 cGy with the applicator and 21.1 cGy without the applicator. For the standard MOSFET, it was 6.8 cGy with the applicator and 27.6 cGy without the applicator. Conclusions: The lens applicator allowed reduction of the differences between the calculated and the measured dose during in-vivo measurement for the lens as compared to in-vivo measurement at the surface of the eyelid. Advances in Knowledge: By using an applicator for in-vivo dosimetry of eye lens, it was possible to reduce the measurement uncertainty.
- Eye Dose Monitoring of PET/CT workers. [JOURNAL ARTICLE]
- Br J Radiol 2014 Aug 11.:20140373.
Objective: The objective of the study was to measure eye dose [Hp(3)] to workers in a busy PET/CT centre. Doses were compared to the proposed new annual dose limit of 20mSv. Methods: We used a newly designed dosimeter to measure eye dose [Hp(3)]. Eye dosimeters were worn with an adjustable headband, with the dose meter positioned adjacent to the left eye. Whole body dose was also recorded using Electronic Personal Dose meters. Exposed staff included radiographers, nurses, and health care assistants. Results: The radiographers received the highest exposure of the staff groups studied, with one radiographer receiving an exposure of 0.5mSv over the three month survey period. The estimated maximum eye dose for one year is approximately 2mSv. The numeric value for eye dose was compared to the numeric value for personal dose equivalent to see if one could be used as an indicator for the other. From our data, a conservative estimate of eye dose Hp(3) (mSv) can be made as being up to approximately twice the numeric value for Hp(10) (mSv). Conclusion: Eye dose was found to be well within the new ICRP and proposed EU limit at our PET/CT centre. Routine whole body dose measurements may be a useful starting point for assessing whether eye dose monitoring should be prioritised in a PET facility. Advances in Knowledge Following the proposal of a reduced eye dose limit, this paper provides new measurement data on staff eye doses for PET/CT workers.
- Musculoskeletal pitfalls and pseudotumors in the pelvis: A pictorial review for body imagers. [JOURNAL ARTICLE]
- Br J Radiol 2014 Aug 6.:20140243.
Many musculoskeletal abnormalities in the pelvis are first seen by body imagers while reviewing pelvic cross-sectional studies, and some of these abnormalities may mimic malignancy or another aggressive process. This paper describes nine musculoskeletal pseudotumors and interpretative pitfalls that may be seen at CT, MRI, and ultrasound imaging of the pelvis. Awareness of these pitfalls and pseudotumors may help avoid misdiagnosis and prevent inappropriate intervention or management.
- Prophylactic radiotherapy against heterotopic ossification following internal fixation of acetabular fractures: a comparative estimate of risk. [JOURNAL ARTICLE]
- Br J Radiol 2014 Aug 4.:20140398.
Objective: Radiotherapy (RT) is effective in preventing heterotopic ossification (HO) around acetabular fractures requiring surgical reconstruction. We audited outcomes and estimated risks from RT prophylaxis, and alternatives of indometacin or no prophylaxis. Methods: Thirty four patients underwent reconstruction of acetabular fractures through a posterior approach, followed by 8 Gy single fraction. Mean age was 44 years. Mean time from surgery to RT was 1.1 days. The major RT risk is radiation-induced fatal cancer. The International Commission on Radiological Protection (ICRP) method was used to estimate risk, and compared to a method (Trott & Kemprad) specifically for estimating RT risk for benign disease. These were compared to risks associated with indometacin and no prophylaxis. Results: Twenty eight patients (82%) developed no HO; 6 developed Brooker Class I, none developed Class II - IV HO. The ICRP method suggests a risk of fatal cancer in the range of 1-in-1000 to 1-in-10,000; the Trott & Kemprad method suggests 1-in-3000. For younger patients this may rise to 1-in-2000; for elderly patients it may fall to 1-in-6000. Risk of death from gastric bleeding or perforation from indometacin is 1-in-180 to 1-in-900, in older patients. Without prophylaxis risk of death from re-operation to remove HO is 1-in-4000 to 1-in-30,000. Conclusions: These results are encouraging, consistent with much larger series, and endorse our multidisciplinary management. Risk estimates can be used in discussion with patients. Advances in knowledge: Risk from RT prophylaxis is small, it is safer than indometacin, and substantially overlaps with the range for no prophylaxis.
- The Role Of Multidetector-Row CT In The Diagnosis, Classification And Management Of Acute Aortic Syndrome. [JOURNAL ARTICLE]
- Br J Radiol 2014 Aug 1.:20140354.
The term acute aortic syndrome ("AAS") encompasses several non-traumatic life threatening pathologies of the thoracic aorta presenting in patients with a similar clinical profile. These include aortic dissection, intramural haematoma, and penetrating atherosclerotic ulcers. These different pathological entities can be indistinguishable on clinical grounds alone and may be confused with other causes of chest pain including myocardial infarction. Multidetector-row computed tomography ("MDCT") is the current modality of choice for imaging AAS with a sensitivity and specificity approaching 100%. Early diagnosis and accurate radiological classification is associated with improved clinical outcomes in AAS. We review the characteristic radiological features of the different pathologies that encompass AAS and highlight the vital role of MDCT in determining the management of these life-threatening conditions.
- Real-Time Phase-Contrast Flow MRI of the Ascending Aorta and Superior Vena Cava as a Function of Intrathoracic Pressure (Valsalva Manoeuvre). [JOURNAL ARTICLE]
- Br J Radiol 2014 Jul 30.:20140401.
Objective: Real-time phase-contrast flow magnetic resonance imaging (MRI) at high spatiotemporal resolution was applied to simultaneously evaluate haemodynamic functions in the ascending aorta and superior vena cava during elevated intrathoracic pressure (Valsalva manoeuvre). Methods: Real-time phase-contrast flow MRI at 3 T was based on highly undersampled radial gradient-echo acquisitions and phase-sensitive image reconstructions by regularized nonlinear inversion. Dynamic alterations of flow parameters were obtained for 19 subjects at 40 ms temporal resolution, 1.33 mm in-plane resolution and 6 mm section thickness. Real-time measurements were performed during normal breathing (10 s), increased intrathoracic pressure (10 s) and recovery (20 s). Results: Real-time measurements were technically successful in all volunteers. During the Valsalva manoeuvre (late strain) and relative to values during normal breathing, the mean peak flow velocity and flow volume decreased significantly in both vessels (p < 0.001) followed by a return to normal parameters within the first 10 s of recovery in the ascending aorta. In contrast, flow in the superior vena cava presented with a brief (1 to 2 heartbeats) but strong overshoot of both the peak velocity and blood volume immediately after pressure release followed by rapid normalization. Conclusion: Real-time phase-contrast flow MRI may assess cardiac haemodynamics non-invasively, in multiple vessels, across the entire luminal area and at high temporal and spatial resolution. Advances in knowledge: Future clinical applications of this technique promise new insights into haemodynamic alterations associated with preclinical congestive heart failure or diastolic dysfunction, especially in cases where echocardiography is technically compromised.
- Diffusion-weighted magnetic resonance imaging as a potential imaging biomarker reflecting the metastatic potential of upper urinary tract cancer. [JOURNAL ARTICLE]
- Br J Radiol 2014 Jul 30.:20130791.
Objectives: To evaluate the role of diffusion-weighted MRI (DW-MRI) as an imaging biomarker for UUTC which has already metastasized or will metastasize soon. Methods: Sixty-one patients clinically diagnosed with UUTC were prospectively enrolled in this study. All the patients underwent MRI including DW-MRI prior to any interventions. Correlations between apparent diffusion coefficient (ADC) and other clinicopathological variables including metastasis-free survival were analysed. Results: Median follow-up period was 938 days. Of 61 patients, 12 patients had any metastases at the initial diagnosis. Eleven patients developed metastases during the follow-up period. These 23 patients were categorized as 'Metastatic'. Of the remaining 38 patients, 35 with a follow-up period longer than 400 days were categorized as 'Localized'. ADC was significantly lower in 'Metastatic' than in 'Localized' (p = 0.0002). Multivariate analysis of preoperative variables identified ADC (cut-off value: 1.08 × 10(-3) mm(2)/s) and clinical T stage based on T2-weighted MRI (T2W-MRI) as an independent predictive factor of metastatic UUTC. Forty-six patients without any metastases at the initial diagnosis were stratified into high-risk group (16 patients with low ADC and clinical T3-4) and low-risk group (30 patients with high ADC or clinical Ta-2). The 3-year metastasis-free survivals were 45% and 93%, respectively. Conclusions: In the current study, UUTC with lower ADC value is more likely to have metastatic potential. Incorporating ADC with clinical T stage helps to differentiate metastatic UUTC at the initial diagnosis. Advances in knowledge: DW-MRI is a potential imaging biomarker reflecting metastatic propensity of UUTC.
- Comparison of 3% sorbitol versus psyllium fibre as oral contrast agents in magnetic resonance enterography. [JOURNAL ARTICLE]
- Br J Radiol 2014 Jul 25.:20140100.
Objectives: To compare the degree of small bowel distension achieved by 3% sorbitol, a high osmolarity solution, and a psyllium based bulk fibre as oral contrast agents (OCAs) in magnetic resonance enterography (MRE). Methods: This retrospective study was approved by our institutional review board. A total of 45 consecutive normal MRE examinations (sorbitol, n=20; psyllium, n=25) were reviewed. The patients received either 1.5L of 3% sorbitol or 2L of 1.6g/kg psyllium prior to imaging. Quantitative small bowel distension measurements were taken in five segments: proximal jejunum, distal jejunum, proximal ileum, distal ileum, and terminal ileum by two independent radiologists. Distension in these five segments were also qualitatively graded from 0 (very poor) to 4 (excellent) by two additional independent radiologists. Statistical analysis comparing the groups and assessing agreement included intraclass coefficients, Students' t-test, and Mann-Whitney U Test. Results: Small bowel distension was not significantly different in any of the 5 small bowel segments between the use of sorbitol and psyllium as OCAs, in both the qualitative (p=0.338-0.908) and quantitative assessments (p=0.083-0.856). The mean bowel distension achieved was 20.1±2.2mm for sorbitol and 19.8±2.5mm for psyllium (p=0.722). Visualization of the ileum was good or excellent in 65% of the examinations in both groups. Conclusion: Sorbitol and psyllium are not significantly different at distending the small bowel and both may be used as OCAs for MRE studies. Advances in knowledge: This is the first study to directly compare the degree of distension in MRE between these two common, readily available and inexpensive OCAs.
- Impact of (18)F-FDG PET/CT on the staging and management of follicular lymphoma. [JOURNAL ARTICLE]
- Br J Radiol 2014 Jul 25.:20140360.
Follicular lymphoma (FL) is the most common indolent lymphoma. Despite the evidence-based utilization of FDG PET/CT in aggressive lymphomas, the utility of PET in FL remains controversial and varies across different jurisdictions. The management of patients with FL differs from aggressive lymphomas and is usually reserved for patients with localized disease in whom long term control may potentially be achieved by involved field radiotherapy (IFRT), or for symptomatic patients with advanced stage disease in whom systemic therapy is indicated. There is a growing body of literature supporting the use of PET/CT in initial staging of FL to guide management decisions. In this review we will summarize the existing literature and present cases from our experience to illustrate current knowledge on the potential role of FDG PET/CT in FL.