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British Journal of Radiology [journal]
- Clinically essential requirement for brain CT with iterative reconstruction. [JOURNAL ARTICLE]
- Br J Radiol 2014 Oct 9.:20140474.
- Ureteral obstruction following renal transplantation: causes, diagnosis and management. [JOURNAL ARTICLE]
- Br J Radiol 2014 Oct 6.:20140169.
Renal transplantation, first performed successfully in the 1950s, is the treatment of choice for most patients with end-stage renal failure. It confers longer-term survival and a better quality of life than both haemodialysis and peritoneal dialysis. The success of renal transplantation is dependent on the preservation of renal graft function and despite the many advances in surgical techniques, immunosuppressive regimens and supportive therapies, many challenges remain including post-operative ureteral obstruction. This complication can pose a risk to graft, and, occasionally, to patient survival. In this pictorial review, we describe the causes of ureteral obstruction following renal transplantation and illustrate the pivotal role of radiology in both diagnosing and managing these complications.
- Mesenteric panniculitis: prevalence, clinicoradiologic presentation and 5-year follow-up. [JOURNAL ARTICLE]
- Br J Radiol 2014 Oct 1.:20140451.
Objectives: To determine prevalence, clinicoradiologic characteristics and outcome of patients with mesenteric panniculitis (MP) in a large hospital-based population. Methods: Consecutive abdominal CT examinations of 3820 patients were evaluated for MP. Clinical characteristics, therapy and outcome of patients with MP were evaluated during a 5-year follow-up period. A matched pair analysis was performed to further investigate the relation between MP and malignancy. Results: 94 (2,5%) MP patients were identified (mean age 66,6 + 11,2 years, 70,2% male). MP coexisted with malignancy (especially prostatic carcinoma) in 48,9% of patients and this was slightly but significantly higher compared to age and sex matched control patients (n=188, 46,3%). In 48 patients MP was presumed to be idiopathic. The most frequent presenting symptom was pain (54,3%). Laboratory findings revealed increased acute-phase reactants in half of the MP patients. CT findings included increased density of mesenterial fat (mean -56,8 + 10,8 HU), fat ring sign, tumoral pseudocapsule and small soft tissue nodules. MP patients (14,6%) developed significantly more malignancies during 5-year follow up compared to the control group (6,9%). One patient was treated with prednisone without satisfactory response. Conclusion: The prevalence of MP in this study was 2,5%. In most patients radiologic features included increased mesenteric fat density, fat ring sign and small soft tissue nodules. MP was associated with a significant higher prevalence of coexisting malignancies and a higher prevalence of future cancer development. Advances in knowledge: A more accurate prevalence of MP on CT is demonstrated. An underlying malignancy may play a role.
- Dynamic MR urography in children with uropathic disease with a combined 2D and 3D acquisition protocol - Comparison with MAG3 scintigraphy. [JOURNAL ARTICLE]
- Br J Radiol 2014 Oct 1.:20140426.
Objectives: The aim of this study was to evaluate combined 2D and 3D dynamic MR urography with respiratory compensation in children with anomalies of the genitourinary tract, allowing for computation of split renal function and assessment of urinary tract obstruction. Methods: Dynamic MR urography was performed in 53 children (3mo to 16y) with anomalies of the urinary tract. A protocol for dynamic MR urography and nephrography was implemented at 1.5T using a navigator triggered 2D TurboFLASH sequence. Split renal function and contrast-medium excretion were assessed after bolus injection of 0.05 mmol/kg body weight gadolinium dimeglumine. In the excretory phase, a 3D gradient-echo data set with high spatial resolution was acquired. In all patients, MAG3 scintigraphy was obtained as a reference standard. Results: In all children, dynamic MR nephrography and urography could be performed with excellent compensation of breathing artifacts providing region-of-interest analysis in nearly identical kidney position. The assessment of contrast-medium excretion into the ureter allowed for discrimination of functional from non-functional stenosis. Split renal function assessed by MRI showed an excellent agreement with the MAG3 reference standard with a correlation coefficient r=0.95. Additionally recorded 3D data sets offered good depiction of anatomical anomalies in all patients. Conclusions: The proposed protocol provides a robust technique for assessment of ureteral obstruction and split renal function with compensation of breathing artifacts, short post-processing time, and excellent 3D spatial resolution. Advances in Knowledge: The combined protocol of 2D and 3D MR urography is an efficient technique for assessment of renal morphology and function.
- Feasibility of automated pancreas segmentation based on dynamic MRI. [JOURNAL ARTICLE]
- Br J Radiol 2014 Oct 1.:20140248.
Objectives: MRI guided radiotherapy is particularly attractive for abdominal targets with low CT contrast. To fully utilize this modality for pancreas tracking, automated segmentation tools are needed. A hybrid gradient, region growth and shape constraint (hGReS) method to segment 2D upper abdominal dynamic MRI is developed for this purpose. Methods: 2D coronal dynamic MR images of 2 healthy volunteers were acquired with a frame rate of 5 f/second. The regions of interest (ROIs) included the liver, pancreas and stomach. The first frame was used as the source where the centers of the ROIs were manually annotated. These center locations were propagated to the next dynamic MRI frame. 4-neighborhood region transfer growth was performed from these initial seeds before refinement using shape constraints. Results from hGReS and 2 other automated segmentation methods using integrated edge detection and region growth (IER), and level set, respectively, were compared to manual contours using Dice's index (DI). Results: For the first patient, hGReS resulted in the organ segmentation accuracy as measure by the DI (0.77) for the pancreas, superior to the level set method (0.72) and IER (0.71). hGReS was shown reproducible on the second subject, achieving a DI of 0.82, 0.92 and 0.93 for the pancreas, stomach and liver, respectively. Motion trajectories derived from the hGReS was high correlated to respiratory motion. Conclusions: We have shown the feasibility of automated segmentation of the pancreas anatomy on dynamic MRI. Advances in knowledge: Using the hybrid method improves segmentation robustness of low-contrast images.
- Phyllodes tumours of the breast. Radiological presentation, management and follow-up. [JOURNAL ARTICLE]
- Br J Radiol 2014 Oct 1.:20140239.
Objectives: Phyllodes tumours (PT) are rare neoplasms accounting for less than 1% of breast lesions. With increased breast awareness and screening programmes, smaller PTs are being detected. The purpose of this study was to determine the clinical, radiological and pathological presentation of PT and to evaluate the role of imaging follow up, for which there are no specific guidelines. Methods: A retrospective study of all patients diagnosed with PT in a symptomatic unit between January 2006 and March 2013 was carried out. Patients were identified using Breast Care and Electronic Patient Record Databases. Results: 53 patients with 54 lesions were diagnosed as having a PT. Median age was 27.5, 35 and 38.5 years for benign, borderline and malignant PT respectively. Borderline and malignant PTs were larger than benign PTs, with mean sizes of 33mm and 42mm compared to 29mm. 38% of PTs were labelled by the reporting radiologist as fibroadenomas including 2 borderline and 1 malignant PT. In 24 % of cases the radiologist raised the possibility of PT in the report. 17 patients (40%) developed a new fibroepithelial breast lesion during follow-up of which 4 were recurrent PT. Conclusion: Despite adequate surgical management, development of further fibroepithelial lesions in the ipsilateral breast is common. Three year clinical surveillance, with the addition of 6-monthly ultrasound is advised for women with initial borderline or malignant PT histology. Advances in knowledge: We propose a follow-up protocol with ultrasound based on the grade of the PT diagnosed for 3 years to detect recurrence.
- Future development of biologically relevant dosimetry. [JOURNAL ARTICLE]
- Br J Radiol 2014 Sep 26.:20140392.
Proton and ion beams are radiotherapy modalities of increasing importance and interest. Because of the different biological dose response of these radiations as compared to high-energy photon beams, the current approach of treatment prescription is based on the product of the absorbed dose to water and a biological weighting factor, but this is found to be insufficient for providing a generic method to quantify the biological outcome of radiation. It is therefore suggested to define new dosimetric quantities which allow a transparent separation of the physical processes from the biological ones. Given the complexity of the initiation and occurrence of biological processes on various time and length scales, and given that neither microdosimetry nor nanodosimetry on their own can fully describe the biological effects as a function of the distribution of energy deposition or ionisation, a multi-scale approach is needed to lay the foundation for the aforementioned new physical quantities relating track structure to relative biological effectiveness in proton and ion beam therapy. This paper reviews the state of the art of microdosimetry, nanodosimetry, track structure simulations, quantification of reactive species, reference radiobiological data, cross section data and multi-scale models of biological response in the context of realising the new quantities. It also introduces the European metrology project, BioQuaRT, which aims to investigate the feasibility of establishing a multi-scale model as the basis of the new quantities. A tentative generic expression of how the weighting of physical quantities at different length scales could be done is presented.
- Impact of the introduction of weekly radiotherapy quality assurance meetings at one UK cancer centre. [Journal Article]
- Br J Radiol 2014 Nov; 87(1043):20140422.
The complexity of radiotherapy planning is increasing rapidly. Delivery and planning is subject to detailed quality assurance (QA) checks. The weakest link is often the oncologists' delineation of the clinical target volume (CTV). Weekly departmental meetings for radiotherapy QA (RTQA) were introduced into the Royal Wolverhampton Hospital, Wolverhampton, UK, in October 2011. This article describes the impact of this on patient care.CTVs for megavoltage photon radiotherapy courses for all radical, adjuvant and palliative treatments longer than five fractions (with the exception of two field tangential breast treatments not enrolled into clinical trials) were reviewed in the RTQA meeting. Audits were carried out in January 2012 (baseline) and September 2013, each over a 4-week period. Adherence to departmental contouring protocols was assessed and the number of major and minor alterations following peer review were determined.There was no statistically significant difference for major alterations between the two study groups; 8 alterations in 80 patients (10%) for the baseline audit vs 3 alterations from 72 patients (4.2%) in the second audit (p = 0.17). A trend towards a reduction in alterations following peer review was observed. There has, however, been a change in practice resulting in a reduction in variation in CTV definition within our centre and greater adherence to protocols. There is increasing confidence in the quality and constancy of care delivered.Introduction of a weekly QA meeting for target volume definition has facilitated consensus and adoption of departmental clinical guidelines within the unit.The weakest areas in radiotherapy are patient selection and definition of the CTV. Engagement in high-quality RTQA is paramount. This article describes the impact of this in one UK cancer centre.
- 4D Radiobiological modelling of the interplay effect in conventionally and hypo-fractionated lung tumour IMRT. [JOURNAL ARTICLE]
- Br J Radiol 2014 Sep 24.:20140372.
Objective: To study the impact of the interplay between respiration-induced tumour motion and MLC leaf movements in IMRT as a function of number of fractions, dose rate on population mean TCP ([Formula: see text]pop) using an in-house developed dose model. Materials and Methods: Delivered dose is accumulated in a voxel-by-voxel basis inclusive of tumour motion over the course of treatment. The effect of interplay on dose and [Formula: see text]pop is studied for conventionally and hypofractionated treatments using DICOM datasets. Moreover, the effect of dose rate on interplay is also studied for single-fraction treatments. Simulations were repeated several times to obtain [Formula: see text]pop for each plan. Results: The average variation observed in mean dose to the target volumes were -0:76±0:36% for the 20 fraction treatment and -0:26±0:68%, -1:05±0:98% for the 3- and single-fraction treatments respectively. For the 20-fraction treatment, the drop in [Formula: see text]pop was -1:05±0:39%, whereas for the 3 and single fraction treatments it was -2:8±1:68% and -4:0±2:84% respectively. By reducing the dose rate from 600 to 300 MU/min for the single-fraction treatments; the drop in [Formula: see text]pop was reduced by ~1.5%. Conclusions: The effect of interplay on [Formula: see text]pop is negligible for conventionally fractionated treatments; whereas considerable drop in [Formula: see text]pop is observed for the 3- and single-fraction treatments. Reduced dose rate could be used in hypofractionated treatments to reduce the interplay effect. Advances in knowledge: A novel in silico dose model is presented to determine the impact of interplay effect in IMRT treatments on [Formula: see text]pop.