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2.  Correlation of the clinical and physical image quality in chest radiography for average adults with a computed radiography imaging system 
The British Journal of Radiology  2013;86(1027):20130077.
Objective:
The purpose of this study was to examine the correlation between the quality of visually graded patient (clinical) chest images and a quantitative assessment of chest phantom (physical) images acquired with a computed radiography (CR) imaging system.
Methods:
The results of a previously published study, in which four experienced image evaluators graded computer-simulated postero-anterior chest images using a visual grading analysis scoring (VGAS) scheme, were used for the clinical image quality measurement. Contrast-to-noise ratio (CNR) and effective dose efficiency (eDE) were used as physical image quality metrics measured in a uniform chest phantom. Although optimal values of these physical metrics for chest radiography were not derived in this work, their correlation with VGAS in images acquired without an antiscatter grid across the diagnostic range of X-ray tube voltages was determined using Pearson’s correlation coefficient.
Results:
Clinical and physical image quality metrics increased with decreasing tube voltage. Statistically significant correlations between VGAS and CNR (R=0.87, p<0.033) and eDE (R=0.77, p<0.008) were observed.
Conclusion:
Medical physics experts may use the physical image quality metrics described here in quality assurance programmes and optimisation studies with a degree of confidence that they reflect the clinical image quality in chest CR images acquired without an antiscatter grid.
Advances in knowledge:
A statistically significant correlation has been found between the clinical and physical image quality in CR chest imaging. The results support the value of using CNR and eDE in the evaluation of quality in clinical thorax radiography.
doi:10.1259/bjr.20130077
PMCID: PMC3922182  PMID: 23568362
3.  Commissioning of a new wide-bore MRI scanner for radiotherapy planning of head and neck cancer 
The British Journal of Radiology  2013;86(1027):20130150.
Objective:
A combination of CT and MRI is recommended for radiotherapy planning of head and neck cancers, and optimal spatial co-registration is achieved by imaging in the treatment position using the necessary immobilisation devices on both occasions, something which requires wide-bore scanners. Quality assurance experiments were carried out to commission a newly installed 1.5-T wide-bore MRI scanner and a dedicated, flexible six-channel phased array head and neck coil.
Methods:
Signal-to-noise ratio (SNR) and spatial signal uniformity were quantified using a homogeneous aqueous phantom, and geometric distortion was quantified using a phantom with water-filled fiducials in a grid pattern. Volunteer scans were also used to determine the in vivo image quality. Clinically relevant T1 weighted and T2 weighted fat-suppressed sequences were assessed in multiple scan planes (both sequences fast spin echo based). The performance of two online signal uniformity correction schemes, one utilising low-resolution reference scans and the other not utilising low-resolution reference scans, was compared.
Results:
Geometric distortions, for a ±35-kHz bandwidth, were <1 mm for locations within 10 cm of the isocentre rising to 1.8 mm at 18 cm away. SNR was above 50, and uniformity in the axial plane was 71% and 95% before and after uniformity correction, respectively.
Conclusion:
The combined performance of the wide-bore scanner and the dedicated coil was adjudged adequate, although superior–inferior spatial coverage was slightly limited in the lower neck.
Advances in knowledge:
These results will be of interest to the increasing number of oncology centres that are seeking to incorporate MRI into planning practice using dedicated equipment.
doi:10.1259/bjr.20130150
PMCID: PMC3922172  PMID: 23690434
4.  Optimisation of coronary angiography exposures requires a multifactorial approach and careful procedural definition 
The British Journal of Radiology  2013;86(1027):20120028.
Objective:
This study investigates the factors associated with higher doses for both single-plane and biplane procedures and establishes centre-specific 75th percentile levels.
Methods:
602 patients undergoing coronary angiography in a large hospital at Sydney were recruited to the study, and causal agents for high radiation doses were investigated: gender, procedural complexity, severity of coronary artery disease, presence of coronary bypass grafts, entry approach (radial or femoral), level of operator experience; and a single-plane or a biplane imaging system was employed.
Results:
The 75th percentile levels were calculated. The results demonstrated that, for both systems, higher exposures were associated with patients who were male (p<0.001), had coronary vessel disease (p<0.001) and had a history of coronary bypass grafts (p<0.001). In addition, for biplane systems, procedural complexity (p<0.001), types of entry approach (p<0.001) and levels of operator experience (p<0.001) significantly impacted upon the dose. Biplane examinations recorded higher doses than single-plane procedures (p<0.001) and the inclusion of left-sided ventriculography contributed to the overall dose by up to 10%.
Conclusion:
The 75th percentile levels in this study represent the tentative reference levels and are 48.9, 44.2 and 56 Gy cm2 for all exposures, single-plane- and biplane-specific exposures, respectively, and compare favourably with the diagnostic reference level values established elsewhere internationally, with only the UK and Irish data being lower.
Advances in knowledge:
Specific agents have been identified for dose-reducing strategies and the importance of operator training is highlighted. The assumption that biplane procedures may reduce the patient dose should be treated with caution.
doi:10.1259/bjr.20120028
PMCID: PMC3922173  PMID: 23719084
5.  Determination and comparison of radiotherapy dose responses for hepatocellular carcinoma and metastatic colorectal liver tumours 
The British Journal of Radiology  2013;86(1027):20130147.
Objective:
The purpose of this study was to seek radiation dose responses separately for primary hepatocellular carcinoma (HCC) and metastatic (MET) colorectal liver tumours to establish tumour control probabilities (TCPs) for radiotherapy (RT) of liver tumours.
Methods:
The records of 36 HCC and 26 MET colorectal liver tumour patients were reviewed. The median dose per fraction and total dose were 4 Gy (2–10 Gy) and 52 Gy (29–83 Gy) for the HCC group and 3.6 Gy (2.0–13.0 Gy) and 55 Gy (30–80 Gy) for the MET group, respectively. Median tumour diameter was 6.6 cm (3.0–18.0 cm) and 5.0 cm (1.0–13.0 cm) for the HCC and MET groups, respectively. A logistic TCP model was fitted to the response data for each group using the maximum likelihood method.
Results:
50% and 90% probabilities of 6-month local control were estimated to be achievable by 2 Gy per fraction equivalent doses (α/β=10 Gy) of 53 Gy and 84 Gy for the HCC group and 70 Gy and 95 Gy for the MET group, respectively. Actuarial 1-year local control for the HCC and MET groups was 65% (45–85%) and 32% (6–58%), respectively, whereas median time to failure was 543 days (374–711 days) and 183 days (72–294 days), respectively.
Conclusion:
Dose–response relationships were found and modelled for the HCC and MET patient groups, with a higher dose required to control MET tumours. RT offers better local control for HCC than for MET colorectal liver tumours at our institution.
Advances in knowledge:
An improved understanding of radiation dose–response relationships for primary and MET colorectal liver tumours will help inform future dose prescriptions.
doi:10.1259/bjr.20130147
PMCID: PMC3922174  PMID: 23690438
6.  Percutaneous ablation of lymph node metastases using CT-guided high-dose-rate brachytherapy 
The British Journal of Radiology  2013;86(1027):20130088.
Objective:
To assess the technical feasibility, safety and clinical outcome of CT-guided high-dose-rate brachytherapy (CT-HDRBT) for achieving local tumour control (LTC) in isolated lymph node metastases.
Methods:
From January 2008 to December 2011, 10 patients (six males and four females) with isolated nodal metastases were treated with CT-HDRBT. Five lymph node metastases were para-aortic, three were at the liver hilum, one at the coeliac trunk and one was a left iliac nodal metastasis. The mean lesion diameter was 36.5 mm (range 12.0–67.0 mm). Patients were followed up by either contrast-enhanced CT or MRI 6 weeks and then every 3 months after the end of treatment. The primary end point was LTC. Secondary end points included primary technical effectiveness rate, adverse events and progression-free survival.
Results:
The first follow-up examination after 6 weeks revealed complete coverage of all nodal metastases treated. There was no peri-interventional mortality or major complications. The mean follow-up period was 13.2 months (range 4–20 months). 2 out of 10 patients (20%) showed local tumour progression 9 and 10 months after ablation. 5 out of 10 patients (50%) showed systemic tumour progression. The mean progression-free interval was 9.2 months (range 2–20 months).
Conclusion:
CT-HDRBT is a safe and effective technique for minimally invasive ablation of nodal metastases.
Advances in knowledge:
CT-HDRBT of lymph node metastases is feasible and safe. CT-HDRBT might be a viable therapeutic alternative to obtain LTC in selected patients with isolated lymph node metastases.
doi:10.1259/bjr.20130088
PMCID: PMC3922177  PMID: 23659925
7.  Reducing metallic artefacts in post-operative spinal imaging: slice encoding for metal artefact correction with dual-source parallel radiofrequency excitation MRI at 3.0 T 
The British Journal of Radiology  2013;86(1027):20120524.
Objective:
To compare the effects of metal artefacts and acquisition time among slice encoding for metal artefact correction (SEMAC), SEMAC with dual-source parallel radiofrequency (SEMAC-DSPRF) transmission and fast spin echo (FSE) images using 3.0-T MRI.
Methods:
The signal-to-noise ratio (SNR) was calculated in a phantom study using a pedicle screw. A total of 16 patients who underwent spinal surgery using pedicle screws were included in the clinical study. T1 weighted FSE, SEMAC and SEMAC-DSPRF images were obtained. Four imaging findings (visibility of the dural sac, neural foramens, bone–implant interface and overall artefacts) were evaluated by using five-point scales independently by two observers. The mean scan time was recorded.
Results:
The mean SNR was 71.2, 25.7 and 28.4 for FSE, SEMAC and SEMAC-DSPRF images, respectively. FSE images were ranked lower than SEMAC and SEMAC-DSPRF images, and ranking of SEMAC and SEMAC-DSPRF images did not differ statistically for all four imaging findings. The mean scan time was 9 min 51 s and 6 min 31 s for SEMAC and SEMAC-DSPRF images, respectively.
Conclusion:
SEMAC can reduce metallic artefacts and improve the visualisation of anatomical structures around metal implants. An additional DSPRF technique can reduce the acquisition time of SEMAC images without the loss of SNR and image quality.
Advances in knowledge:
This study demonstrates that the use of the DSPRF transmission technique can reduce the acquisition time of SEMAC images without loss of image quality in patients with metal implants.
doi:10.1259/bjr.20120524
PMCID: PMC3922180  PMID: 23719085
8.  Optimisation of patient dose for the horizontal beam technique in lateral lumbar spine radiographic examinations 
The British Journal of Radiology  2013;86(1027):20130053.
In the emergency department, patients undergoing lateral lumbar spine radiography examinations are positioned either lying on their side on an X-ray table with the X-ray beam vertical or lying supine on a trolley with the X-ray beam horizontal. The measured dose–area product (DAP) values were found to differ significantly, typically 1.3 Gy cm2 for those patients examined on the X-ray table and 2.7 Gy cm2 for those on a trolley. This work investigates the reason for higher DAP values with the horizontal beam technique. The UK’s current recommended national diagnostic reference level (NDRL) for the lateral lumbar spine is 2.5 Gy cm2. The measurements of body diameter on volunteers showed that rotating the patients from their side to their back resulted in an increase in tissue thickness of between 2 cm and 9 cm for the lumbar region. X-ray absorption increases exponentially with increasing tissue thickness. An increase of 5 cm in body diameter for a lateral lumbar spine at 93 kV will increase the DAP by more than two-fold. Mathematical modelling and measurements with polymethyl methacrylate provided data to predict the tube potential increase necessary to reduce the DAP. For the horizontal beam technique, the tube potential was increased from 93 kV to 102 kV and the average DAP reduced to 2.3 Gy cm2. Radiographic technique should be understood when auditing the dose. Tube potential must be increased to optimise the horizontal beam technique. The 2.5-Gy cm2 NDRL relates predominantly to the more common vertical beam technique. Separate local diagnostic reference levels for horizontal and vertical beam techniques are recommended.
doi:10.1259/bjr.20130053
PMCID: PMC3922181  PMID: 23652542
9.  Technical and dosimetric aspects of iodine-125 seed reimplantation in suboptimal prostate implants 
The British Journal of Radiology  2013;86(1026):20130058.
Objective:
Brachytherapy employing iodine-125 seeds is an established treatment for low-risk prostate cancers. Post-implant dosimetry (PID) is an important tool for identifying suboptimal implants. The aim of this work was to improve suboptimal implants by a subsequent iodine-125 seed top-up (reimplantation), based on the PID results.
Methods:
Of 255 patients treated between 2009 and 2012, 6 were identified as having received suboptimal implants and were scheduled for seed top-up. Needle configurations and the number of top-up seeds were determined based on post-implant CT images as well as a reimplantation treatment plan. An average of 14 seeds per patient were implanted during each top-up. Dosimetric outcome was assessed via target parameters and doses received by organs at risk.
Results:
All six patients had a successful top-up, with a 67% increase in the mean dose delivered to 90% of the prostate volume and a 40% increase in the volume that receives 100% of the prescribed dose. However, the final dosimetric assessment was based on the same seed activity, as the planning system does not account for the decay of the initially implanted seeds. Although physical dosimetry is not influenced by different seed activities (doses are calculated to infinity), the radiobiological implications might be slightly different from the situation when optimal implantation is achieved with one treatment only.
Conclusion:
Seed reimplantation in suboptimal prostate implants is feasible and leads to successful clinical outcomes.
Advances in knowledge:
Suboptimal prostate implants can occur for various reasons. This work shows that seed reimplantation as salvage therapy can lead to an optimal dosimetric outcome with manageable normal tissue effects.
doi:10.1259/bjr.20130058
PMCID: PMC3664978  PMID: 23520225
10.  Skeletal muscle evaluation by MRI in a rabbit model of acute ischaemia 
Zhang, H | Wang, X | Guan, M | Li, C | Luo, L
The British Journal of Radiology  2013;86(1026):20120042.
Objective:
To assess rhabdomyolysis-associated skeletal muscle changes induced by complete ischaemia in rabbits using MRI.
Methods:
Acute ischaemia was induced in the right hind limb of 34 New Zealand white rabbits by arterial ligation. MRI of vastus lateralis was carried out pre-operatively and every hour post-operatively up to 7 h. T1 weighted images, T2 weighted images with fat suppression, T2 maps and diffusion tensor scans were obtained. The correlation of MRI findings with histopathological changes in biopsies of vastus lateralis was examined.
Results:
Histopathology demonstrated early cellular oedema 1 h post ischaemia and irreversible injuries by 7 h, including loss of striation and broken muscle fibres. T2 weighted images with fat suppression showed inhomogeneous high signal intensity of vastus lateralis, which progressively increased from 2 h following ischaemia. The T2 relaxation rate of ischaemic vastus lateralis was significantly greater than normal muscle (p<0.001) and demonstrated a linear increase with time following ischaemia. A similar linear increase was also found in the ischaemic vastus lateralis apparent diffusion coefficient (ADC) 1–5 h post ischaemia (p=0.006). Both the T2 ADC and fractional anisotropy (FA) were significantly higher on the ischaemic side 7 h post ischaemia (for T2, p=0.02; for ADC, p=0.004).
Conclusion:
Muscle oedema is detectable on MR images and is reflected well by T2, ADC and FA values. MRI may have value in clinical evaluation of rhabdomyolysis.
Advances in knowledge:
Ischaemic changes detected by MRI may have value in the diagnosis of rhabdomyolysis.
doi:10.1259/bjr.20120042
PMCID: PMC3664979  PMID: 23658466
11.  The role of the breast radiologist in evaluation of breast incidentalomas detected on 18-fludeoxyglucose positron emission tomography/CT 
The British Journal of Radiology  2013;86(1026):20130034.
Objective:
To evaluate the significance of incidentally discovered breast lesions on 18-fludeoxyglucose (18F-FDG) positron emission tomography (PET)/CT.
Methods:
6050 18F-FDG PET/CT studies, performed between January 2009 and February 2012, were retrospectively reviewed. 55 lesions in 50 patients were identified. Additional work-up, including mammography, ultrasound, follow-up 18F-FDG PET/CT and biopsy, was available for 39 incidental breast lesions in 36 patients. All patients were female, with mean age 61.5 years (range 36–90 years). The maximum standardised uptake value (SUVmax), CT size and CT Breast Imaging Reporting and Data System (BI-RADS®) scores were compared between the malignant and the benign subgroups, using the unpaired t-test and Fisher’s exact test. Tests were two-sided and a p-value of <0.05 was considered to be significant.
Results:
Incidental breast lesions were identified in 50 (0.8%) of 6050 18F-FDG PET/CT studies. 21 (53.8%) of the 39 breast incidentalomas were malignant on biopsy or imaging, of which 15 (38.5%) represented a second primary breast cancer. A statistically significant difference in the mean SUVmax between malignant and benign breast lesions was observed (p=0.021). Malignancy was significantly more common in the CT BI-RADS Category 4 or greater groups (76.2%; p=0.0105).
Conclusion:
Incidental breast lesions detected at 18F-FDG PET/CT are uncommon. When detected, however, they may represent malignancy in up to 53.8% of cases.
Advances in knowledge:
SUVmax and CT findings at 18F-FDG PET/CT can assist with differentiating benign and malignant breast conditions, guiding further evaluation with dedicated breast imaging.
Review of 18F-FDG PET/CT-detected breast lesions by a breast radiologist may be helpful in determining the need for and correlation with further breast imaging.
Radiologists and nuclear medicine physicians should be cognisant of breast pathology when reporting 18F-FDG PET/CT image data sets.
doi:10.1259/bjr.20130034
PMCID: PMC3664982  PMID: 23568361
12.  Effects of the frame acquisition rate on the sensitivity of gastro-oesophageal reflux scintigraphy 
The British Journal of Radiology  2013;86(1026):20130084.
Objective:
To compare the sensitivity of gastro-oesophageal reflux (GOR) scintigraphy at 5-s and 60-s frame acquisition rates.
Methods:
GOR scintigraphy of 50 subjects (1 month–20 years old, mean 42 months) were analysed concurrently using 5-s and 60-s acquisition frames. Reflux episodes were graded as low if activity was detected in the distal half of the oesophagus and high if activity was detected in its upper half or in the oral cavity. For comparison purposes, detected GOR in any number of 5-s frames corresponding to one 60-s frame was counted as one episode.
Results:
A total of 679 episodes of GOR to the upper oesophagus were counted using a 5-s acquisition technique. Only 183 of such episodes were detected on 60-s acquisition images. To the lower oesophagus, a total of 1749 GOR episodes were detected using a 5-s acquisition technique and only 1045 episodes using 60-s acquisition frames (these also included the high-level GOR on 5-s frames counted as low level on 60-s acquisition frames). 10 patients had high-level GOR episodes that were detected only using a 5-s acquisition technique, leading to a different diagnosis in these patients. No correlation between the number of reflux episodes and the gastric emptying rates was noted.
Conclusion:
The 5-s frame acquisition technique is more sensitive than the 60-s frame acquisition technique for detecting both high- and low-level GOR.
Advances in knowledge:
Brief GOR episodes with a relatively low number of radioactive counts are frequently indistinguishable from intense background activity on 60-s acquisition frames.
doi:10.1259/bjr.20130084
PMCID: PMC3664983  PMID: 23520226
13.  CT imaging as a prognostic indicator for patients with pulmonary injury from acute paraquat poisoning 
Zhang, H | Liu, P | Qiao, P | Zhou, J | Zhao, Y | Xing, X | Li, G
The British Journal of Radiology  2013;86(1026):20130035.
Objective:
CT imaging may be an effective diagnostic method for assessing the extent and progression of pulmonary injury in patients with acute paraquat (PQ) poisoning.
Methods:
A retrospective review of 78 patients with acute PQ poisoning (survivor group, n=42; non-survivor group, n=36) was conducted to examine the lung segment involvement and CT image characteristics from baseline (first CT scan at a mean of 2.4 days after poisoning) to treatment time (second CT scan 3 days after the first). We examined the association between prognosis and pulmonary lesions indicated by characteristic effusion, fibrosis and consolidation in CT images.
Results:
Significant differences were apparent in CT images at baseline and after 3 days between the survivor and the non-survivor groups, with higher levels of pulmonary segment involvement, effusion, consolidation and fibrosis observed in the non-survivor group at baseline (p<0.05). The non-survivor group also showed rapid lesion progression. The receiver operating characteristic curve indicated that the best prognostic value of baseline CT scanning was achieved when performed 2–3 days following the initial exposure.
Conclusion:
Prognosis correlated with increasing lung segment involvement, extent of disease characteristics visualised using CT and speed of lesion progression from baseline. Prognostic evaluation using CT scanning can be used to effectively provide earlier treatment for patients at risk for severe complications associated with PQ toxicity, such as acidosis; leukocytosis; and renal, hepatic and pancreatic failures.
Advances in knowledge:
Chest CT scan can be used 2–3 days following acute PQ poisoning to determine prognosis.
doi:10.1259/bjr.20130035
PMCID: PMC3664987  PMID: 23652630
14.  Gd-EOB-DTPA-enhanced MRI for the assessment of liver function and volume in liver cirrhosis 
The British Journal of Radiology  2013;86(1026):20120653.
Objective:
The aims of this study were to use dynamic hepatocyte-specific contrast-enhanced MRI to evaluate liver volume and function in liver cirrhosis, correlate the results with standard scoring models and explore the inhomogeneous distribution of liver function in cirrhotic livers.
Methods:
10 patients with liver cirrhosis and 20 healthy volunteers, serving as controls, were included. Hepatic extraction fraction (HEF), input relative blood flow and mean transit time were calculated on a voxel-by-voxel basis using deconvolutional analysis. Segmental and total liver volumes as well as segmental and total hepatic extraction capacity, expressed in HEFml, were calculated. An incongruence score (IS) was constructed to reflect the uneven distribution of liver function. The Mann–Whitney U-test was used for group comparison of the quantitative liver function parameters, liver volumes and ISs. Correlations between liver function parameters and clinical scores were assessed using Spearman rank correlation.
Results:
Patients had larger parenchymal liver volume, lower hepatocyte function and more inhomogeneous distribution of function compared with healthy controls.
Conclusion:
The study demonstrates the non-homogeneous nature of liver cirrhosis and underlines the necessity of a liver function test able to compensate for the heterogeneous distribution of liver function in patients with diseased liver parenchyma.
Advances in knowledge:
The study describes a new way to quantitatively assess the hepatic uptake of gadoxetate or gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid in the liver as a whole as well as on a segmental level.
doi:10.1259/bjr.20120653
PMCID: PMC3664988  PMID: 23403453
15.  Ultrasonography-guided core needle biopsy for the thyroid nodule: does the procedure hold any benefit for the diagnosis when fine-needle aspiration cytology analysis shows inconclusive results? 
The British Journal of Radiology  2013;86(1025):20130007.
Objective:
We evaluated the diagnostic role of ultrasonography-guided core needle biopsy (CNB) according to ultrasonography features of thyroid nodules that had inconclusive ultrasonography-guided fine-needle aspiration (FNA) results.
Methods:
A total of 88 thyroid nodules in 88 patients who underwent ultrasonography-guided CNB because of previous inconclusive FNA results were evaluated. The patients were classified into three groups based on ultrasonography findings: Group A, which was suspicious for papillary thyroid carcinoma (PTC); Group B, which was suspicious for follicular (Hurthle cell) neoplasm; and Group C, which was suspicious for lymphoma. The final diagnoses of the thyroid nodules were determined by surgical confirmation or follow-up after ultrasonography-guided CNB.
Results:
Of the 88 nodules, the malignant rate was 49.1% in Group A, 12.0% in Group B and 90.0% in Group C. The rates of conclusive ultrasonography-guided CNB results after previous incomplete ultrasonography-guided FNA results were 96.2% in Group A, 64.0% in Group B and 90.0% in Group C (p=0.001). 12 cases with inconclusive ultrasonography-guided CNB results were finally diagnosed as 8 benign lesions, 3 PTCs and 1 lymphoma. The number of previous ultrasonography-guided FNA biopsies was not significantly different between the conclusive and the inconclusive result groups of ultrasonography-guided CNB (p=0.205).
Conclusion:
Ultrasonography-guided CNB has benefit for the diagnosis of thyroid nodules with inconclusive ultrasonography-guided FNA results. However, it is still not helpful for the differential diagnosis in 36% of nodules that are suspicious for follicular neoplasm seen on ultrasonography.
Advances in knowledge:
This study shows the diagnostic contribution of ultrasonography-guided CNB as an alternative to repeat ultrasonography-guided FNA or surgery.
doi:10.1259/bjr.20130007
PMCID: PMC3635802  PMID: 23564885
16.  Predictive value of modelled tumour control probability based on individual measurements of in vitro radiosensitivity and potential doubling time 
The British Journal of Radiology  2013;86(1025):20130015.
Objective:
The aim of this study was to compare patient-specific radiobiological parameters with population averages in predicting the clinical outcome after radiotherapy (RT) using a tumour control probability (TCP) model based on the biological effective dose (BED).
Methods:
A previously published study of 46 head and neck carcinomas with individually identified radiobiological parameters, radiosensitivity and potential doubling time (Tpot), and known tumour size was investigated. These patients had all been treated with external beam RT, and the majority had also received brachytherapy. The TCP for each individual based on the BED using patient-specific radiobiological parameters was compared with the TCP based on the BED using average radiobiological parameters (α=0.3 Gy−1, Tpot=3 days).
Results:
43 patients remained in the final analysis. There was only a weak trend for increasing local tumour control with increasing BED in both groups. However, when the TCP was calculated, the use of patient-specific parameters was better for identifying local control correctly. The sensitivity and specificity for tumour-specific parameters were 63% and 80%, respectively. The corresponding values for population-based averages were 0% and 91%, respectively. The positive predictive value was 92% when tumour-specific parameters were used compared with 0% for population-based averages. A receiver operating characteristic curve confirmed the superiority of patient-specific parameters over population averages in predicting local control.
Conclusion:
Individual radiobiological parameters are better than population-derived averages when used in a mathematical model to predict TCP after curative RT in head and neck carcinomas.
Advances in knowledge:
TCP based on individual radiobiological parameters is better than TCP based on population-based averages for identifying local control correctly.
doi:10.1259/bjr.20130015
PMCID: PMC3635803  PMID: 23479396
17.  MR cholangiopancreatography at 3.0 T in children: diagnostic quality and ability in assessment of common paediatric pancreatobiliary pathology 
The British Journal of Radiology  2013;86(1025):20130036.
Objective:
To assess the diagnostic quality of MR cholangiopancreatography (MRCP) at 3.0 T in children and to assess its diagnostic ability in answering the clinical query. Also, to determine the frequency of artefacts and anatomic variations in ductal anatomy.
Methods:
Consecutive MRCPs performed in children using a 3-T scanner were retrospectively reviewed to note indications, findings, imaging diagnosis, normal variants, quality and artefacts. Analysis was performed based on the final diagnosis assigned by pathology or the combination of clinical, laboratory, imaging features and follow-up to determine whether it was possible to answer the clinical query by MRCP findings.
Results:
There were 82 MRCPs performed at 3.0 T on 77 children. 42/82 (51%) MRCPs were of good quality, 35/82 (43%) MRCPs were suboptimal but diagnostic and the remaining 5/82 (6%) MRCPs were non-diagnostic. MRCP answered the clinical query in 61/82 (74%) cases; however, it did not answer the clinical query in 11/82 (14%) cases and was equivocal in 10/82 (12%) cases. There was significant association between the quality of MRCP and the ability of MRCP to answer the clinical query (p<0.0001). 64/82 (78%) MRCP examinations had at least 1 artefact. Variation in the bile duct anatomy was seen in 27/77 (35%) children.
Conclusion:
MRCP performed at 3.0 T is of diagnostic quality in most cases and is able to provide an answer to the clinical query in the majority of cases.
Advances in knowledge:
3-T MRCP is feasible and useful in the assessment of pancreatobiliary abnormalities in children.
doi:10.1259/bjr.20130036
PMCID: PMC3635804  PMID: 23457194
18.  Ultrasound of distal brachialis tendon attachment: normal and abnormal findings 
The British Journal of Radiology  2013;86(1025):20130004.
Objective:
To demonstrate normal and abnormal findings of distal brachialis tendon attachment in cadavers, normal volunteers and patients by means of ultrasound.
Methods:
3 cadaveric specimens, 30 normal volunteers and 125 patients were evaluated by means of ultrasound. Correlative MRI was obtained in volunteers.
Results:
In all cases, ultrasound demonstrated the distal brachialis tendon shaped by two distinct tendons belonging to the deep head and superficial head of the brachialis muscle. Correlative MRI demonstrated that the brachialis is composed of two distinct tendons in 83% of volunteers (25/30). In the patient group, four avulsions with bony detachment involving the deep head, one delayed onset muscular soreness and three tendinous detachments with no bony avulsion involving one or two tendons were identified. The four patients with bony avulsion were immediately referred to the orthopaedic surgeon for a pre-surgical evaluation. Patients without bony avulsion were not referred to the surgeon.
Conclusion:
Detailed anatomy of the distal tendon is discernible in 100% of cases with ultrasound. There are two distinct tendons, and ultrasound can differentiate isolated lesions. In patients with distal brachialis tendon lesions, ultrasound may modify the clinical management of the patient.
Advances in knowledge
Detailed anatomy of the distal brachialis tendon is discernible with ultrasound and there are two distinct tendons.
doi:10.1259/bjr.20130004
PMCID: PMC3635801  PMID: 23420050
19.  Values of pathological analysis of lost tissue fragments in the vacuum canister during a vacuum-assisted stereotactic biopsy of the breast 
The British Journal of Radiology  2013;86(1025):20120270.
Objective:
Determine values of pathological analysis of the canister content during a vacuum-assisted breast biopsy (VABB).
Methods:
Approval was obtained from the ethical committee. Prospective radiological and pathological analyses of the canister content collected during 231 VABBs performed on 231 patients were carried out. χ2 test was used to determine predictors on canister pathology.
Results:
The canister pathology was reported separately in 212 cases. It showed only blood in 78/212 (37%) cases and benign (including high-risk lesions) and malignant results in, respectively, 113/212 (53%) and 21/212 (10%) cases. Respective specimen analysis was benign, including high-risk lesions in 162/212 cases (76%) and malignant in 50/212 (24%) cases. Microcalcifications were documented on canister X-ray in 70/231 (30%) cases. There was significant association between the canister and the specimen pathology (p<0.0001). In none of the cases was microcalcifications seen exclusively in the canister content or pathological upgrading found in the canister content compared with the specimen.
Conclusion:
Small tissue fragments and microcalcifications may be lost in the canister during a VABB. Nevertheless, our results did not show any significant value for systematic analysis of the canister content.
Advances in knowledge:
There is no added diagnostic value to retrieval and analysis of tissue lost in the canister during a VABB.
doi:10.1259/bjr.20120270
PMCID: PMC3635795  PMID: 23520227
20.  Severe back pain and lower extremities weakness in a young male 
The British Journal of Radiology  2013;86(1025):20110685.
doi:10.1259/bjr.20110685
PMCID: PMC3635793  PMID: 23537521
21.  Clinical correlation of a new practical MRI method for assessing central lumbar spinal stenosis 
The British Journal of Radiology  2013;86(1025):20120180.
Objective:
To evaluate interobserver agreement and determine whether a new MRI grading system agrees with symptoms and neurological signs.
Methods:
We examined 160 patients (72 males and 88 females; mean age 57 years) who underwent MRI of the lumbar spine at our institution and were evaluated by two musculoskeletal radiologists. The presence and grade of central lumbar spinal stenosis (CLSS) at L3–4, L4–5 and L5–S1 were assessed according to a new grading system, the Lee system. The results were correlated with clinical manifestations and neurological examinations [positive neurological manifestation (PNM) and negative neurological manifestation (NNM)]. Statistical analyses were performed using kappa statistics and non-parametric correlation analysis (Spearman’s correlation).
Results:
Interobserver agreement in the grading of CLSS between the two readers was substantial (κ=0.780). Interobserver agreement of the L4–5 level and older age group was high (0.789, 0.814). The correlation coefficient (R) of Reader 1 between MRI Grades 0, 1, 2 or 3 and neurological manifestations (negative or positive) was 0.654; the R of Reader 2 was 0.591. In the younger age group (<57 years), the R of Reader 1 was 0.634 and the R of Reader 2 was 0.500. In the older age group (≥57 years), the R of Reader 1 was 0.650 and the R of Reader 2 was 0.645. Correlation coefficients were higher at the L3–4 level (0.612–0.678) than at other levels but did not show statistical significance (p>0.05).
Conclusion:
Interobserver agreement for the new CLSS grading system was substantial. Grade 0 was associated with NNMs and Grade 3 with PNMs in this cohort. Grade 2 demonstrates more cases of PNM than NNM but requires further evaluation. Correlations between MRI grades and clinical manifestations were moderate and slightly higher in older patients.
Advances in knowledge:
The new practical MRI grading method can be useful in the categorisation of CLSS and shows strong clinical correlation.
doi:10.1259/bjr.20120180
PMCID: PMC3635794  PMID: 23426848
22.  A practical MRI grading system for cervical foraminal stenosis based on oblique sagittal images 
The British Journal of Radiology  2013;86(1025):20120515.
Objective:
To propose a new and practical MRI grading method for cervical neural foraminal stenosis and to evaluate its reproducibility.
Methods:
We evaluated 50 patients (37 males and 13 females, mean age 49 years) who visited our institution and underwent oblique sagittal MRI of the cervical spine. A total of 300 foramina and corresponding nerve roots in 50 patients were qualitatively analysed from C4–5 to C6–7. We assessed the grade of cervical foraminal stenosis at the maximal narrowing point according to the new grading system based on T2 weighted oblique sagittal images. The incidence of each of the neural foraminal stenosis grades according to the cervical level was analysed by χ2 tests. Intra- and interobserver agreements between two radiologists were analysed using kappa statistics. Kappa value interpretations were poor (κ<0.1), slight (0.1≤κ≤0.2), fair (0.2<κ≤0.4), moderate (0.4<κ≤0.6), substantial (0.6<κ≤0.8) and almost perfect (0.8<κ≤1.0).
Results:
Significant stenoses (Grades 2 and 3) were rarely found at the C4–5 level. The incidence of Grade 3 at the C5–6 level was higher than that at other levels, a difference that was statistically significant. The overall intra-observer agreement according to the cervical level was almost perfect. The agreement at each level was almost perfect, except for only substantial agreement at the right C6–7 by Reader 2. No statistically significant differences were seen according to the cervical level. Overall kappa values of interobserver agreement according to the cervical level were almost perfect. In addition, the agreement of each level was almost perfect. Overall intra- and interobserver agreement for the presence of foraminal stenosis (Grade 0 vs Grades 1, 2 and 3) and for significant stenosis (Grades 0 and 1 vs Grades 2 and 3) showed similar results and were almost perfect. However, only substantial agreement was seen in the right C6–7.
Conclusion:
A new grading system for cervical foraminal stenosis based on oblique sagittal MRI provides reliable assessment and good reproducibility. This new grading system is a useful and easy method for the objective evaluation of cervical neural foraminal stenosis by radiologists and clinicians.
Advances in knowledge:
The use of the new grading system for cervical foraminal stenosis based on oblique sagittal MRI can be a useful method for evaluating cervical neural foraminal stenosis.
doi:10.1259/bjr.20120515
PMCID: PMC3635796  PMID: 23410800
23.  Positron emission tomography (PET) attenuation correction artefacts in PET/CT and PET/MRI 
The British Journal of Radiology  2013;86(1025):20120570.
Objective:
To compare the effect of implanted medical materials on 18F-fludeoxyglucose (18F-FDG) positron emission tomography (PET)/MRI using a Dixon-based segmentation method for MRI-based attenuation correction (MRAC), PET/CT and CT-based attenuation-corrected PET (PETCTAC).
Methods:
12 patients (8 males and 4 females; age 58±11 years) with implanted medical materials prospectively underwent whole-body 18F-FDG PET/CT and PET/MRI. CT, MRI and MRAC maps as well as PETCTAC and PETMRAC images were reviewed for the presence of artefacts. Their morphology and effect on the estimation of the 18F-FDG uptake (no effect, underestimation, overestimation compared with non-corrected images) were compared. In PETMRAC images, a volume of interest was drawn in the area of the artefact and in a reference site (contralateral body part); the mean and maximum standardised uptake values (SUVmean; SUVmax) were measured.
Results:
Of 27 implanted materials (20 dental fillings, 3 injection ports, 3 hip prostheses and 1 sternal cerclage), 27 (100%) caused artefacts in CT, 19 (70%) in T1 weighted MRI and 17 (63%) in MRAC maps. 20 (74%) caused a visual overestimation of the 18F-FDG uptake in PETCTAC, 2 (7%) caused an underestimation and 5 (19%) had no effect. In PETMRAC, 19 (70%) caused spherical extinctions and 8 (30%) had no effect. Mean values for SUVmean and SUVmax were significantly decreased in artefact-harbouring sites (p<0.001).
Conclusion:
Contrary to PET attenuation correction artefacts in PET/CT, which often show an overestimation of the 18F-FDG uptake, MRAC artefacts owing to implanted medical materials in most cases cause an underestimation.
Advances in knowledge:
Being aware of the morphology of artefacts owing to implanted medical materials avoids interpretation errors when reading PET/MRI.
doi:10.1259/bjr.20120570
PMCID: PMC3635797  PMID: 23580397
24.  Acceptability of oral iodinated contrast media: a head-to-head comparison of four media 
The British Journal of Radiology  2013;86(1025):20120636.
Objective:
To assess the palatability of iodinated oral contrast media commonly used in abdominopelvic CT and CT colonography (CTC).
Methods:
80 volunteers assessed the palatability of a 20-ml sample of a standard 30 mg ml−1 dilution of Omnipaque® (iohexol; GE Healthcare, Cork, Ireland), Telebrix® (meglumine ioxithalamate; Guerbet, Aulnay-sous-Bois, France), Gastromiro® (iopamidol; Bracco, High Wycombe, UK) and Gastrografin® (sodium diatrizoate and meglumine diatrizoate; Bayer, Newbury, UK) in a computer-generated random order.
Results:
Gastrografin is rated significantly less palatable than the remaining media (p<0.005). Omnipaque and Telebrix are significantly more palatable than Gastromiro. No difference existed between Omnipaque and Telebrix. 39% of participants would refuse to consume the quantities of Gastrografin required for a CTC examination compared with Telebrix (7%) and Omnipaque (9%) (p<0.05).
Conclusion:
Omnipaque and Telebrix are significantly more palatable than both Gastromiro and Gastrografin, with participants more willing to ingest them in larger quantities as well as being less expensive.
Advances in knowledge:
Omnipaque and Telebrix are significantly more palatable iodinated oral contrast media than both Gastromiro and Gastrografin, which has potential implications in compliance with both abdominopelvic CT and CTC.
doi:10.1259/bjr.20120636
PMCID: PMC3635798  PMID: 23564884
25.  Visualisation of the left anterior descending coronary artery on CT images used for breast radiotherapy planning 
The British Journal of Radiology  2013;86(1025):20120643.
Objective:
To assess the visualisation of the left anterior descending (LAD) coronary artery on CT images used for breast radiation treatment planning.
Methods:
Delineation of the LAD artery was achieved for 25 breast patients by 1 radiologist and 1 radiation oncologist independently on two sets of images for each patient: one pre-operative CT scan using intravenous (IV) contrast media to determine the primary gross tumour volume (GTV) and one post-operative CT scan used for treatment planning. A Student’s paired t-test was used to compare the number of CT slices in which the LAD was visible for each patient in the two series. Interpolations and extrapolations of the LAD volume were performed for the left-sided cases using a published heart atlas in order to report doses to the LAD structure.
Results:
There was a non-significant difference between the results with and without IV contrast media (p=0.34 for the radiologist; p=0.90 for the radiation oncologist). The visible LAD artery corresponded to a 30% portion (range 12–47%) of the interpolated structure. The maximum dose to the left artery varied widely, from 2.7 to 41.7 Gy, in the group of patients with left breast tumours. The largest values (>25 Gy) corresponded to those patients in whom the LAD artery distal extremity lay inside the breast fields.
Conclusions:
With the current planning CT protocol, only one-third of the LAD artery could be objectively visualised. Contrast-enhanced imaging used for GTV delineation before the breast surgery did not improve the visualisation of the artery.
Advances in Knowledge:
This study has revealed the lack of consistency that may be encountered when contouring heart vessels, thereby questioning the reliability of dose reporting.
doi:10.1259/bjr.20120643
PMCID: PMC3635799  PMID: 23440165

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