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5.  Three-dimensional airway lumen volumetry: comparison with bronchial wall area and parenchymal densitometry in assessment of airway obstruction in pulmonary emphysema 
The British Journal of Radiology  2012;85(1020):1525-1532.
Objectives
The purpose of this study was to compare three-dimensional airway lumen volumetry with bronchial wall area and parenchymal densitometry in the assessment of airway obstruction in pulmonary emphysema.
Methods
56 patients, who were smokers, underwent CT examination and pulmonary function tests (PFTs). For quantitative assessments, the following parameters were computationally calculated: (1) percentage of voxels −950, −960 and −970 HU in the lung (%LAA−950, %LAA−960 and %LAA−970, respectively); (2) percentage of partial bronchi luminal volumes per total luminal volumes (LVmain, main and distal bronchial volume/total luminal volume; LVlobe, lobar and distal bronchial volume/total luminal volume); and (3) mean wall area percentages of segmental bronchi of the right apical and left apicoposterior segment (WA%seg) and of subsegmental bronchi (WA%sub) in the upper lobes. These parameters were correlated with PFTs and statistically compared between a chronic obstructive pulmonary disease (COPD) group [forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC)<70] and a non-COPD group.
Results
FEV1, maximum mid-expiratory flow rate and forced expiratory flow at 25% vital capacity had significant correlation with LVmain (r>0.53, p<0.0001), LVlobe (r>0.52, p<0.0001), WA%seg (|r|>0.29, p<0.05) and WA%sub (|r|>0.31, p<0.05). FEV1/FVC had significant correlation with all parameters (0.27<|r|<0.52, p<0.05). LVmain and LVlobe and WA%seg and WA%sub were significantly different between the two groups (LVmain and LVlobe; p<0.0001, WA%seg and WA%sub; p<0.05).
Conclusions
Bronchial luminal volumetric assessment better reflected the airflow limitation parameters.
Advances in knowledge
Bronchial luminal volumetric assessment can potentially be used to gauge airflow limitation in pulmonary emphysema.
doi:10.1259/bjr/22602417
PMCID: PMC3611709  PMID: 22932062
6.  Thin-section CT findings in Pseudomonas aeruginosa pulmonary infection 
The British Journal of Radiology  2012;85(1020):1533-1538.
Objective
The aim of this study was to assess clinical and pulmonary thin-section CT findings in patients with acute Pseudomonas aeruginosa (PA) pulmonary infection.
Methods
We retrospectively identified 44 patients with acute PA pneumonia who had undergone chest thin-section CT examinations between January 2004 and December 2010. We excluded nine patients with concurrent infections. The final study group comprised 35 patients (21 males, 14 females; age range 30–89 years, mean age 66.9 years) with PA pneumonia. The patients' clinical findings were assessed. Parenchymal abnormalities, enlarged lymph nodes and pleural effusion were evaluated on thin-section CT.
Results
Underlying diseases included malignancy (n=13), a smoking habit (n=11) and cardiac disease (n=8). CT scans of all patients revealed abnormal findings, including ground-glass opacity (n=34), bronchial wall thickening (n=31), consolidation (n=23) and cavities (n=5). Pleural effusion was found in 15 patients.
Conclusion
PA pulmonary infection was observed in patients with underlying diseases such as malignancy or a smoking habit. The CT findings in patients with PA consisted mainly of ground-glass attenuation and bronchial wall thickening.
Advances in knowledge
The CT findings consisted mainly of ground-glass attenuation, bronchial wall thickening and cavities. These findings in patients with an underlying disease such as malignancy or a smoking habit may be suggestive of pneumonia caused by PA infection.
doi:10.1259/bjr/54468236
PMCID: PMC3611710  PMID: 22844034
7.  Evaluation of the trade-offs encountered in planning and treating locally advanced head and neck cancer: intensity-modulated radiation therapy vs dual-arc volumetric-modulated arc therapy 
The British Journal of Radiology  2012;85(1020):1539-1545.
Objective
The primary purpose of this study was to assess the practical trade-offs between intensity-modulated radiation therapy (IMRT) and dual-arc volumetric-modulated arc therapy (DA-VMAT) for locally advanced head and neck cancer (HNC).
Methods
For 15 locally advanced HNC data sets, nine-field step-and-shoot IMRT plans and two full-rotation DA-VMAT treatment plans were created in the Pinnacle3 v. 9.0 (Philips Medical Systems, Fitchburg, WI) treatment planning environment and then delivered on a Clinac iX (Varian Medical Systems, Palo Alto, CA) to a cylindrical detector array. The treatment planning goals were organised into four groups based on their importance: (1) spinal cord, brainstem, optical structures; (2) planning target volumes; (3) parotids, mandible, larynx and brachial plexus; and (4) normal tissues.
Results
Compared with IMRT, DA-VMAT plans were of equal plan quality (p>0.05 for each group), able to be delivered in a shorter time (3.1 min vs 8.3 min, p<0.0001), delivered fewer monitor units (on average 28% fewer, p<0.0001) and produced similar delivery accuracy (p>0.05 at γ2%/2mm and γ3%/3mm). However, the VMAT plans took more planning time (28.9 min vs 7.7 min per cycle, p<0.0001) and required more data for a three-dimensional dose (20 times more, p<0.0001).
Conclusions
Nine-field step-and-shoot IMRT and DA-VMAT are both capable of meeting the majority of planning goals for locally advanced HNC. The main trade-offs between the techniques are shorter treatment time for DA-VMAT but longer planning time and the additional resources required for implementation of a new technology. Based on this study, our clinic has incorporated DA-VMAT for locally advanced HNC.
Advances in knowledge
DA-VMAT is a suitable alternative to IMRT for locally advanced HNC.
doi:10.1259/bjr/26344684
PMCID: PMC3611711  PMID: 22806619
8.  Incidence of symptomatic brain metastasis following radical radiotherapy for non-small cell lung cancer: is there a role for prophylactic cranial irradiation? 
The British Journal of Radiology  2012;85(1020):1546-1550.
Objective
Brain metastases following radical radiotherapy for non-small cell lung cancer (NSCLC) are a recognised phenomenon; however, the incidence of symptomatic brain metastasis is currently unknown. The aim of the study was to identify the number of patients, staged in accordance with National Institute for Health and Clinical Excellence (NICE) guidance, who developed symptomatic brain metastasis following radical radiotherapy. There are two aims: to evaluate NICE guidance; and to provide vital information on the likely benefit of prophylactic cranial irradiation (PCI) in reducing neurological symptoms from brain metastasis.
Methods
A retrospective review of 455 patients with NSCLC who had undergone radical radiotherapy in 2009 and 2010 was performed. Computer-based systems were used to identify patient and tumour demographics, the staging procedures performed and whether brain imaging had identified brain metastasis in the follow-up period.
Results
The total number of patients with brain metastasis within 6 months was 3.7%. The proportion of brain metastasis within 6 months in Stage I, II and III NSCLC throughout both years was 2.8%, 1.0% and 5.7%, respectively. Within the follow-up period (median 16 months, range 6–30 months), the total number of patients who developed symptomatic brain metastasis was 7.9%.
Conclusion
Patients staged in accordance with NICE guidance, of whom only 7.7% underwent brain staging, have a minimal incidence of brain metastasis following radical radiotherapy. The number of patients developing symptoms from brain metastasis following radical radiotherapy may be less than the morbidity caused by PCI.
Advances in knowledge
This finding supports the NICE guidance and brings into question the potential benefit of PCI.
doi:10.1259/bjr/23314501
PMCID: PMC3611712  PMID: 22993386
9.  Imaging of scleroma in the head and neck 
The British Journal of Radiology  2012;85(1020):1551-1555.
We review the appearance of scleroma in the head and neck on imaging. Scleroma is a chronic granulomatous disease that primarily affects the nasal cavity, but the pharynx and larynx may also be involved. On imaging, nasal scleroma appears as bilateral or unilateral expanded homogeneous nasal masses that may exhibit hyperintense signal on T1 weighted images. Pharyngeal scleroma commonly narrows the pharyngeal lumen and may involve the soft and hard palate. Imaging is essential to detect the extent of subglottic stenosis in patients with laryngeal scleroma. Rarely, scleroma may involve the orbit or the middle ear. Imaging is essential for the early diagnosis of scleroma and for differentiating it from other granulomatous and neoplastic lesions. Also, imaging is important for treatment planning and follow-up of patients after therapy.
doi:10.1259/bjr/15189057
PMCID: PMC3611713  PMID: 22898154
10.  Battlefield radiology 
The British Journal of Radiology  2012;85(1020):1556-1565.
With the increasing tempo of military conflicts in the last decade, much has been learnt about imaging battlefield casualties in the acute setting. Ultrasound in the form of focused abdominal sonography in trauma (FAST) has proven invaluable in emergency triage of patients for immediate surgery. Multidetector CT allows accurate determination of battlefield trauma injuries. It permits the surgeons and anaesthetists to plan their interventions more thoroughly and to be made aware of clinically occult injuries. There are common injury patterns associated with blast injury, gunshot wounds and blunt trauma. While this body of knowledge is most applicable to the battlefield, there are parallels with peacetime radiology, particularly in terrorist attacks and industrial accidents. This pictorial review is based on the experiences of a UK radiologist deployed in Afghanistan in 2010.
doi:10.1259/bjr/33335273
PMCID: PMC3611714  PMID: 22806621
11.  The many faces of posterior reversible encephalopathy syndrome 
The British Journal of Radiology  2012;85(1020):1566-1575.
The classic imaging findings of posterior reversible encephalopathy syndrome (PRES) are of bilateral parietal and occipital subcortical vasogenic oedema, and are well established in the literature. As experience with PRES grows, varied and atypical presentations are being increasingly described. This pictorial review illustrates the variable presentations of PRES, including cases with atypical imaging findings. We illustrate cases of PRES with varying distributions of vasogenic oedema as well as cases with atypical imaging findings, such as variations of haemorrhage and restricted diffusion. Atypical imaging findings should not dissuade the diagnosis of PRES in the appropriate clinical situation, and knowledge of the varied appearance and atypical findings of PRES allows the radiologist to make this diagnosis.
doi:10.1259/bjr/25273221
PMCID: PMC3611715  PMID: 23175479
12.  Technical note: 9-month repositioning accuracy for functional response assessment in head and neck chemoradiotherapy 
The British Journal of Radiology  2012;85(1020):1576-1580.
The use of thermoplastic immobilisation masks in head and neck radiotherapy is now common practice. The accuracy of these systems has been widely studied, but always within the context and time frame of the radiation delivery—some 6–8 weeks. There is growing current interest in the use of functional imaging to assess the response to treatment, particularly in the head and neck. It is therefore of interest to determine the accuracy with which functional images can be registered to baseline CT over the extended periods of time used for functional response assessment: 3–6 months after radiotherapy. In this study, repeated contrast-enhanced diagnostic quality CT and mid-quality localisation CT from a positron emission tomography/CT scanner were available for five time points over a period of 9 months (before, during and up to 6 months after chemoradiotherapy) for a series of eight patients enrolled in a clinical pilot study. All images were acquired using thermoplastic immobilisation masks. The overall set-up accuracy obtained from this 9-month study of 5.5±3.2 mm (1 standard deviation) and 1.9±1.3° (1 standard deviation) is in agreement with published data acquired over 6–8 weeks. No statistically significant change in set-up error was seen with time. This work indicates that thermoplastic immobilisation masks can be used to accurately align multimodality functional image data for assessment of the response to treatment in head and neck patients over extended follow-up periods.
doi:10.1259/bjr/47081873
PMCID: PMC3611716  PMID: 23175480
13.  A right atrial mass—but where is it coming from? 
The British Journal of Radiology  2012;85(1020):1581-1583.
doi:10.1259/bjr/20189031
PMCID: PMC3611717  PMID: 23175481
14.  Index to Authors 2012 
The British Journal of Radiology  2012;85(1020):1584-1594.
PMCID: PMC3611718
15.  Radiation-induced cancer: a modern view 
The British Journal of Radiology  2012;85(1020):e1166-e1173.
Diagnostic medical radiation has been the most rapidly increasing component of population background radiation exposure in Western countries over the past decade. This trend is set to increase as CT scanning is readily available with burgeoning use in everyday clinical practice. Consequently, the issue of cancer induction from the doses received during diagnostic medical exposures is highly relevant. In this review we explain current understanding of potential cancer induction at low doses of sparsely ionising radiation. For cancers that may be induced at low doses, a mechanistic description of radiation-induced cancer is discussed, which, in combination with extrapolation of data based on population cohort studies, provides the basis of the currently accepted linear no-threshold model. We explore the assumptions made in deriving risk estimates, the controversies surrounding the linear no-threshold model and the potential future challenges facing clinicians and policy-makers with regards to diagnostic medical radiation and cancer risk, most notably the uncertainties regarding deriving risk estimates from epidemiological data at low doses.
doi:10.1259/bjr/25026140
PMCID: PMC3611719  PMID: 23175483
16.  Application of breast tomosynthesis in screening: incremental effect on mammography acquisition and reading time 
The British Journal of Radiology  2012;85(1020):e1174-e1178.
Objective
The aim of this study was to supplement the paucity of information available on logistical aspects of the application of three-dimensional (3D) mammography in breast screening.
Methods
We prospectively examined the effect on radiographers' and radiologists' workload of implementing 3D mammography in screening by comparing image acquisition time and screen-reading time for two-dimensional (2D) mammography with that of combined 2D+3D mammography. Radiologists' accuracy was also calculated.
Results
Average acquisition time (measured from start of first-view breast positioning to compression release at completion of last view) for seven radiographers, based on 20 screening examinations, was longer for 2D+3D (4 min 3 s; range 3 min 53 s–4 min 18 s) than 2D mammography (3 min 13 s; range 3 min 0 s–3 min 26 s; p<0.01). Average radiologists' reading time per screening examination (three radiologists reading case-mix of 100 screens: 10 cancers, 90 controls) was longer for 2D+3D (77 s; range 60–90 s) than for 2D mammography (33 s; range 25–46 s; p<0.01). 2D+3D screen-reading was associated with detection of more cancers and with substantially fewer recalls than 2D mammography alone.
Conclusion
Relative to standard 2D mammography, combined 2D+3D mammography prolongs image acquisition time and screen-reading time (at initial implementation), and appears to be associated with improved screening accuracy.
Advances in knowledge
These findings provide relevant information to guide larger trials of integrated 3D mammography (2D+3D) and its potential implementation into screening practice.
doi:10.1259/bjr/19385909
PMCID: PMC3611720  PMID: 23175484
17.  Experimental study of single-pin puncture asymmetrical hydroablation using a conformational radiofrequency ablation electrode in ex vivo ox liver 
The British Journal of Radiology  2012;85(1020):e1179-e1183.
Objective
The aim of this study was to evaluate the feasibility of single-pin puncture asymmetrical hydroablation in liver using the multipole cluster conformable radiofrequency ablation electrode.
Methods
The conformable electrode used in this study consists of both a main electrode in a central cannula and a circle of subelectrodes comprising two groups of six subelectrodes located on opposite sides (A and B) of the circle. The two subelectrode groups can be extended to different lengths independently of one another, resulting in asymmetrical shapes. Ablation experiments were performed using ex vivo ox liver. The experiments included six groups based on six potential electrode deployments in which the subelectrodes on sides A and B were fully extended, half extended or fully retracted. After ablation, the transverse diameters of the resulting necrotic tissue from sides A and B were measured. The experiment was conducted in 12 separate sites for each group.
Results
When the subelectrodes were arranged symmetrically (either fully extended or half extended on both sides), the mean transverse diameter of necrotic tissue was similar for both sides A and B. When the subelectrodes were arranged asymmetrically, the fully extended side showed a significantly greater mean transverse diameter of necrotic tissue than the half extended or fully retracted side.
Conclusion
In this study, the WHK 3-8-4 multipole cluster conformable radiofrequency ablation electrode was able to produce both symmetrical and asymmetrical necrotic tissue patterns in the liver.
Advances in knowledge
The size and shape of the ablation can be altered by both withdrawing and extending the subelectrodes to different lengths.
doi:10.1259/bjr/21634918
PMCID: PMC3611721  PMID: 22932060
18.  Who's the doctor? Patients' perceptions of the role of the breast radiologist: a lesson for all radiologists 
The British Journal of Radiology  2012;85(1020):e1184-e1189.
Objective
The aim of this study was to explore patients' perceptions of the role of the radiologist in their care.
Methods
The questionnaire used was designed in conjunction with a psychologist who had an interest in oncology, and piloted. The final questionnaires were distributed to patients attending the breast clinic at St James's Hospital, Dublin, Ireland, from 1 March to 1 July 2011. Patients requiring imaging (mammography and/or ultrasound) were asked to complete the same questionnaire again after imaging procedures were performed. Paired t-tests were used to assess for changes in parameters, including ranking of members of the breast care team in order of perceived importance and levels of anxiety pre and post consultation with the radiologist.
Results
306 patients were recruited. 76% of patients thought that radiologists were radiographers and only 14% knew that radiologists were medical doctors. Nearly 40% of patients did not consider that radiologists had a role to play in their care. There was no statistically significant difference in the ranking of team members pre and post consultation. There was a significant improvement in patient anxiety levels after consultation with the breast radiologist, which is likely to be due to the patient learning the outcome of tests performed.
Conclusion
There is a lack of awareness amongst patients and amongst our colleagues in paramedical disciplines regarding the roles and responsibilities of the modern radiologist.
Advances in knowledge
Radiology must act to increase public awareness so that future changes in the health service will reflect the scope and importance of the speciality.
doi:10.1259/bjr/74006772
PMCID: PMC3611722  PMID: 22932065
19.  Application of prospective ECG-triggered dual-source CT coronary angiography for infants and children with coronary artery aneurysms due to Kawasaki disease 
Duan, Y | Wang, X | Cheng, Z | Wu, D | Wu, L
The British Journal of Radiology  2012;85(1020):e1190-e1197.
Objectives
The aim of this study was to prospectively evaluate the initial application and value of prospective electrocardiogram (ECG)-triggered dual-source CT coronary angiography (DSCTCA) in the diagnosis of infants and children with coronary artery aneurysms due to Kawasaki disease.
Methods
19 children [12 males; mean age 13.47 months, range 3 months to 5 years; mean heart rate 112 beats per minute (bpm), range 83–141 bpm] underwent prospective ECG-triggered DSCTCA with free breathing. Subjective image quality was assessed on a five-point scale (1, excellent; 5, non-diagnostic) by two blinded observers. The location, number and size of each aneurysm were observed and compared with those of transthoracic echocardiography (TTE) performed within 1 week. Interobserver agreement concerning the subjective image quality was evaluated with Cohen's κ-test. Bland–Altman analysis was used to evaluate the agreement on measurements (diameter and length of aneurysms) between DSCTCA and TTE. The average effective dose required for DSCTCA was calculated for all children.
Results
All interobserver agreement for subjective image quality assessment was excellent (κ=0.87). The mean±standard deviation (SD) aneurysm diameter with DSCTCA was 0.76±0.36 cm and with TTE was 0.76±0.39 cm. The mean±SD aneurysm length with DSCTCA was 2.06±1.35 cm and with TTE was 2.00±1.22 cm. The Bland–Altman plot for agreement between DSCTCA and TTE measurements showed good agreement. The mean effective dose was 0.36±0.06 mSv.
Conclusion
As an alternative diagnostic modality, prospective ECG-triggered DSCTCA with excellent image quality and low radiation exposure has been proved useful for diagnosing infants and children with coronary artery aneurysms due to Kawasaki disease.
Advances in knowledge
Prospective ECG–triggered DSCTCA for infants and children allows rapid, accurate assessment of coronary aneurysms due to Kawasaki diseases, compared with TTE.
doi:10.1259/bjr/18174517
PMCID: PMC3611723  PMID: 22932064
20.  Assessing response of myeloma bone disease with diffusion-weighted MRI 
The British Journal of Radiology  2012;85(1020):e1198-e1203.
Objectives
To measure apparent diffusion coefficient (ADC) values in patients with active myeloma and remission and to determine whether changes differ in those responding/progressing on treatment. The relationship between changes in marrow fat and ADC was also explored.
Methods
20 patients were recruited. T1 weighted, T2 weighted, short tau inversion-recovery, diffusion-weighted and two-point Dixon MRI of the lumbar spine and pelvis were performed at baseline, 4–6 weeks and 20 weeks.
Results
ADC values of active disease (mean 761.2±255×10−6 mm2 s−1) were significantly higher (p=0.047) than marrow in remission (mean 601.8±459×10−6 mm2 s−1). Changes in ADC in responders showed a significant increase at 4–6 weeks (p=0.005) but no significant change between baseline and 20 weeks (p=0.733). ADCs in progressing and stable patients did not change significantly between either time point. Pearson's correlation coefficient between change in fat fraction and change in the number of pixels with an ADC of ≤655×10−6 mm2 s−1 was 0.924, indicating a significant correlation (p<0.001).
Conclusion
ADC values in active myeloma are significantly higher than marrow in remission, indicating the potential for diffusion-weighted MRI to quantify the transition from active disease to remission and vice versa. This study confirms significant changes in ADC in patients responding to treatment and indirect evidence from two-point Dixon MRI suggests that these changes are influenced by changes in marrow fat.
Advances in knowledge
ADC of active myeloma is significantly higher than marrow in remission; the direction of ADC changes on treatment is dependent on the timing of measurements and is influenced by changes in marrow fat.
doi:10.1259/bjr/52759767
PMCID: PMC3611724  PMID: 23175485
21.  Semi-automated and automated glioma grading using dynamic susceptibility-weighted contrast-enhanced perfusion MRI relative cerebral blood volume measurements 
The British Journal of Radiology  2012;85(1020):e1204-e1211.
Objective
Despite the established role of MRI in the diagnosis of brain tumours, histopathological assessment remains the clinically used technique, especially for the glioma group. Relative cerebral blood volume (rCBV) is a dynamic susceptibility-weighted contrast-enhanced perfusion MRI parameter that has been shown to correlate to tumour grade, but assessment requires a specialist and is time consuming. We developed analysis software to determine glioma gradings from perfusion rCBV scans in a manner that is quick, easy and does not require a specialist operator.
Methods
MRI perfusion data from 47 patients with different histopathological grades of glioma were analysed with custom-designed software. Semi-automated analysis was performed with a specialist and non-specialist operator separately determining the maximum rCBV value corresponding to the tumour. Automated histogram analysis was performed by calculating the mean, standard deviation, median, mode, skewness and kurtosis of rCBV values. All values were compared with the histopathologically assessed tumour grade.
Results
A strong correlation between specialist and non-specialist observer measurements was found. Significantly different values were obtained between tumour grades using both semi-automated and automated techniques, consistent with previous results. The raw (unnormalised) data single-pixel maximum rCBV semi-automated analysis value had the strongest correlation with glioma grade. Standard deviation of the raw data had the strongest correlation of the automated analysis.
Conclusion
Semi-automated calculation of raw maximum rCBV value was the best indicator of tumour grade and does not require a specialist operator.
Advances in knowledge
Both semi-automated and automated MRI perfusion techniques provide viable non-invasive alternatives to biopsy for glioma tumour grading.
doi:10.1259/bjr/13908936
PMCID: PMC3611725  PMID: 23175486
22.  Kinetics of intravenous radiographic contrast medium injections as used on CT: simulation with time delay differential equations in a basic human cardiovascular multicompartment model 
The British Journal of Radiology  2012;85(1020):e1212-e1218.
Objectives
To develop a multicompartment model of only essential human body components that predicts the contrast medium concentration vs time curve in a chosen compartment after an intravenous injection. Also to show that the model can be used to time adequately contrast-enhanced CT series.
Methods
A system of linked time delay instead of ordinary differential equations described the model and was solved with a Matlab program (Matlab v. 6.5; The Mathworks, Inc., Natick, MA). All the injection and physiological parameters were modified to cope with normal or pathological situations. In vivo time–concentration curves from the literature were recalculated to validate the model.
Results
The recalculated contrast medium time–concentration curves and parameters are given. The results of the statistical analysis of the study findings are expressed as the median prediction error and the median absolute prediction error values for both the time delay and ordinary differential equation systems; these are situated well below the generally accepted maximum 20% limit.
Conclusion
The presented program correctly predicts the time–concentration curve of an intravenous contrast medium injection and, consequently, allows an individually tailored approach of CT examinations with optimised use of the injected contrast medium volume, as long as time delay instead of ordinary differential equations are used.
Advances in knowledge
The presented program offers good preliminary knowledge of the time–contrast medium concentration curve after any intravenous injection, allowing adequate timing of a CT examination, required by the short scan time of present-day scanners. The injected volume of contrast medium can be tailored to the individual patient with no more contrast medium than is strictly needed.
doi:10.1259/bjr/83724929
PMCID: PMC3611726  PMID: 23175487
23.  Comparison of the clinical characteristics and imaging findings of acute cholangitis with and without biliary dilatation 
The British Journal of Radiology  2012;85(1020):e1219-e1225.
Objective
To evaluate the causes of acute cholangitis without biliary dilatation and to compare the clinical characteristics and the imaging findings between patients with acute cholangitis with and without biliary dilatation.
Methods
93 patients diagnosed with acute cholangitis underwent contrast-enhanced CT. Among them, 17 patients were classified as not having biliary dilatation (Group 1) and 76 patients were classified as having biliary dilatation (Group 2). The causes of acute cholangitis were evaluated in both groups. Clinical characteristics and imaging findings were compared between the two groups.
Results
The causes of acute cholangitis without biliary dilatation included common bile duct (CBD) stones (n=11), CBD sludge (n=3), a passed stone (n=1) and unknown causes (n=2). The total bilirubin levels of Group 1 were significantly lower than those of Group 2 (p=0.001). By contrast, Group 1 had higher median alanine aminotransferase (ALT) levels than Group 2 (p=0.04). The length of hospital stay was significantly longer in Group 2 than in Group 1 patients (p<0.001). In the imaging findings, the extent of transient hepatic attenuation differences (THADs) (p=0.003) were significantly smaller in Group 1 than in Group 2.
Conclusion
CBD stones and sludge were the most common causes of acute cholangitis in patients without biliary dilatation. These patients showed lower levels of bilirubin and higher levels of ALT than those with acute cholangitis with biliary dilatation, and had a shorter duration of hospital stay. The extent of THADs was the only discriminative CT finding between the two groups.
Advances in knowledge
Acute cholangitis can present without biliary dilatation on imaging, and the most common causes are CBD stones and sludge. The patients with acute cholangitis without biliary dilatation have different clinical characteristics and imaging findings compared with those with acute cholangitis presenting with biliary dilatation.
doi:10.1259/bjr/21182091
PMCID: PMC3611727  PMID: 23175488
24.  Sensitivity and specificity of mammographic screening as practised in Vermont and Norway 
The British Journal of Radiology  2012;85(1020):e1226-e1232.
Objective
The aim of this study was to examine the sensitivity and specificity of screening mammography as performed in Vermont, USA, and Norway.
Methods
Incident screening data from 1997 to 2003 for female patients aged 50–69 years from the Vermont Breast Cancer Surveillance System (116 996 subsequent screening examinations) and the Norwegian Breast Cancer Screening Program (360 872 subsequent screening examinations) were compared. Sensitivity and specificity estimates for the initial (based on screening mammogram only) and final (screening mammogram plus any further diagnostic imaging) interpretations were directly adjusted for age using 5-year age intervals for the combined Vermont and Norway population, and computed for 1 and 2 years of follow-up, which ended at the time of the next screening mammogram.
Results
For the 1-year follow-up, sensitivities for initial assessments were 82.0%, 88.2% and 92.5% for 1-, 2- and >2-year screening intervals, respectively, in Vermont (p=0.022). For final assessments, the values were 73.6%, 83.3% and 81.2% (p=0.047), respectively. For Norway, sensitivities for initial assessments were 91.0% and 91.3% (p=0.529) for 2- and >2-year intervals, and 90.7% and 91.3%, respectively, for final assessments (p=0.630). Specificity was lower in Vermont than in Norway for each screening interval and for all screening intervals combined, for both initial (90.6% vs 97.8% for all intervals; p<0.001) and final (98.8% vs 99.5% for all intervals; p<0.001) assessments.
Conclusion
Our study showed higher sensitivity and specificity in a biennial screening programme with an independent double reading than in a predominantly annual screening program with a single reading.
Advances in knowledge
This study demonstrates that higher recall rates and lower specificity are not always associated with higher sensitivity of screening mammography. Differences in the screening processes in Norway and Vermont suggest potential areas for improvement in the latter.
doi:10.1259/bjr/15168178
PMCID: PMC3611728  PMID: 22993383
25.  Comparison of visual grading and free-response ROC analyses for assessment of image-processing algorithms in digital mammography 
The British Journal of Radiology  2012;85(1020):e1233-e1241.
Objective
To compare two methods for assessment of image-processing algorithms in digital mammography: free-response receiver operating characteristic (FROC) for the specific task of microcalcification detection and visual grading analysis (VGA).
Methods
The FROC study was conducted prior to the VGA study reported here. 200 raw data files of low breast density (Breast Imaging–Reporting and Data System I–II) mammograms (Novation DR, Siemens, Germany)—100 of which abnormal—were processed by four image-processing algorithms: Raffaello (IMS, Bologna, Italy), Sigmoid (Sectra, Linköping, Sweden), and OpView v. 2 and v. 1 (Siemens, Erlangen, Germany). Four radiologists assessed the mammograms for the detection of microcalcifications. 8 months after the FROC study, a subset (200) of the 800 images was reinterpreted by the same radiologists, using the VGA methodology in a side-by-side approach. The VGA grading was based on noise, saturation, contrast, sharpness and confidence with the image in terms of normal structures. Ordinal logistic regression was applied; OpView v. 1 was the reference processing algorithm.
Results
In the FROC study all algorithms performed better than OpView v. 1. From the current VGA study and for confidence with the image, Sigmoid and Raffaello were significantly worse (p<0.001) than OpView v. 1; OpView v. 2 was significantly better (p=0.01). For the image quality criteria, results were mixed; Raffaello and Sigmoid for example were better than OpView v. 1 for sharpness and contrast (although not always significantly).
Conclusion
VGA and FROC discordant results should be attributed to the different clinical task addressed.
Advances in knowledge
The method to use for image-processing assessment depends on the clinical task tested.
doi:10.1259/bjr/22608279
PMCID: PMC3611729  PMID: 22844032

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