Showing papers in "British Journal of Radiology in 2012"
TL;DR: The field of nanotechnology with a focus on recent gold nanoparticle research which has led to early-phase clinical trials is introduced, and the pre-clinical evidence for gold nanoparticles as sensitisers with ionising radiation in vitro and in vivo at kilovoltage and megavoltage energies is discussed.
Abstract: Gold nanoparticles are emerging as promising agents for cancer therapy and are being investigated as drug carriers, photothermal agents, contrast agents and radiosensitisers. This review introduces the field of nanotechnology with a focus on recent gold nanoparticle research which has led to early-phase clinical trials. In particular, the pre-clinical evidence for gold nanoparticles as sensitisers with ionising radiation in vitro and in vivo at kilovoltage and megavoltage energies is discussed.
884 citations
TL;DR: This review aims to compare different methods of measuring visceral adiposity with emphasis on their advantages and drawbacks in clinical practice to evaluate the potential risk of development of pathologies as well as providing an accurate prognosis.
Abstract: As a result of the rising epidemic of obesity, understanding body fat distribution and its clinical implications is critical to timely treatment. Visceral adipose tissue is a hormonally active component of total body fat, which possesses unique biochemical characteristics that influence several normal and pathological processes in the human body. Abnormally high deposition of visceral adipose tissue is known as visceral obesity. This body composition phenotype is associated with medical disorders such as metabolic syndrome, cardiovascular disease and several malignancies including prostate, breast and colorectal cancers. Quantitative assessment of visceral obesity is important for evaluating the potential risk of development of these pathologies, as well as providing an accurate prognosis. This review aims to compare different methods of measuring visceral adiposity with emphasis on their advantages and drawbacks in clinical practice.
618 citations
TL;DR: The various EUS techniques available for clinical use are described, the published evidence on musculoskeletal applications of EUS is presented, and the technical issues, limitations and future perspectives of this method in the assessment of the musculOSkeletal system are discussed.
Abstract: Ultrasound elastography (EUS) is a method to assess the mechanical properties of tissue, by applying stress and detecting tissue displacement using ultrasound. There are several EUS techniques used in clinical practice; strain (compression) EUS is the most common technique that allows real-time visualisation of the elastographic map on the screen. There is increasing evidence that EUS can be used to measure the mechanical properties of musculoskeletal tissue in clinical practice, with the future potential for early diagnosis to both guide and monitor therapy. This review describes the various EUS techniques available for clinical use, presents the published evidence on musculoskeletal applications of EUS and discusses the technical issues, limitations and future perspectives of this method in the assessment of the musculoskeletal system.
305 citations
TL;DR: Current understanding of potential cancer induction at low doses of sparsely ionising radiation, 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 are explained.
Abstract: 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.
185 citations
TL;DR: Clinical audit was regarded as a key tool in ensuring that justification becomes an effective, transparent and accountable part of normal radiological practice, and would be facilitated by the "3 As": awareness, appropriateness and audit.
Abstract: Objectives: The Radiation Protection of Patients Unit of the International Atomic Energy Agency (IAEA) is concerned about the effectiveness of justification of diagnostic medical exposures. Recent published work and the report of an initial IAEA consultation in the area gave grounds for such concerns. There is a significant level of inappropriate usage, and, in some cases, a poor level of awareness of dose and risk among some key groups involved. This article aims to address this. Methods: The IAEA convened a second group of experts in November 2008 to review practical and achievable actions that might lead to more effective justification. Results: This report summarises the matters that this group considered and the outcome of their deliberations. There is a need for improved communication, both within professions and between professionals on one hand, and between professionals and the patients/public on the other. Coupled with this, the issue of consent to imaging procedures was revisited. The need for ...
180 citations
TL;DR: The diagnostic accuracy of BT was superior to DM in an enriched population of diseased patients and benign and/or healthy patients and the ability of radiologists to detect breast cancers using one-view breast tomosynthesis and two-view digital mammography was compared.
Abstract: Objective Our aim was to compare the ability of radiologists to detect breast cancers using one-view breast tomosynthesis (BT) and two-view digital mammography (DM) in an enriched population of diseased patients and benign and/or healthy patients. Methods All participants gave informed consent. The BT and DM examinations were performed with about the same average glandular dose to the breast. The study population comprised patients with subtle signs of malignancy seen on DM and/or ultrasonography. Ground truth was established by pathology, needle biopsy and/or by 1-year follow-up by mammography, which retrospectively resulted in 89 diseased breasts (1 breast per patient) with 95 malignant lesions and 96 healthy or benign breasts. Two experienced radiologists, who were not participants in the study, determined the locations of the malignant lesions. Five radiologists, experienced in mammography, interpreted the cases independently in a free-response study. The data were analysed by the receiver operating c...
175 citations
TL;DR: The aim of this review is to present an overview of the role of coronary CT angiography on cardiac imaging, with focus on coronary artery disease in terms of the diagnostic and prognostic value of coronaryCT angiographic.
Abstract: Coronary CT angiography has been increasingly used in the diagnosis of coronary artery disease owing to rapid technological developments, which are reflected in the improved spatial and temporal resolution of the images. High diagnostic accuracy has been achieved with multislice CT scanners (64 slice and higher), and in selected patients coronary CT angiography is regarded as a reliable alternative to invasive coronary angiography. With high-quality coronary CT imaging increasingly being performed, patients can benefit from an imaging modality that provides a rapid and accurate diagnosis while avoiding an invasive procedure. Despite the tremendous contributions of coronary CT angiography to cardiac imaging, study results reported in the literature should be interpreted with caution as there are some limitations existing within the study design or related to patient risk factors. In addition, some attention must be given to the potential health risks associated with the ionising radiation received during cardiac CT examinations. Radiation dose associated with coronary CT angiography has raised serious concerns in the literature, as the risk of developing malignancy is not negligible. Various dose-saving strategies have been implemented, with some of the strategies resulting in significant dose reduction. The aim of this review is to present an overview of the role of coronary CT angiography on cardiac imaging, with focus on coronary artery disease in terms of the diagnostic and prognostic value of coronary CT angiography. Various approaches for dose reduction commonly recommended in the literature are discussed. Limitations of coronary CT angiography are identified. Finally, future directions and challenges with the use of coronary CT angiography are highlighted.
169 citations
TL;DR: Novel imaging techniques are being developed that may improve the ability of MRI and ultrasound to assess tendon and ligament disease, which has been validated against surgical and histological findings.
Abstract: MRI and ultrasound are now widely used for the assessment of tendon and ligament abnormalities. Healthy tendons and ligaments contain high levels of collagen with a structured orientation, which gives rise to their characteristic normal imaging appearances as well as causing particular imaging artefacts. Changes to ligaments and tendons as a result of disease and injury can be demonstrated using both ultrasound and MRI. These have been validated against surgical and histological findings. Novel imaging techniques are being developed that may improve the ability of MRI and ultrasound to assess tendon and ligament disease.
155 citations
TL;DR: Low ADC value was correlated with positive expression of ER, PR, increased Ki-67 index, and increased MVD of breast cancer and no correlations were observed between mean ADC value and human growth factor receptor 2 expression, tumour size and lymph node metastasis.
Abstract: Objective: The aim of this study was to correlate the apparent diffusion coefficient (ADC) value of breast cancer with prognostic factors. Methods: 335 patients with invasive ductal carcinoma not otherwise specified (IDC NOS) and ductal carcinoma in situ (DCIS) who underwent breast MRI with diffusion-weighted imaging were included in this study. ADC of breast cancer was calculated using two b factors (0 and 1000 s mm–2). Mean ADCs of IDC NOS and DCIS were compared and evaluated. Among cases of IDC NOS, mean ADCs were compared with lymph node status, size and immunochemical prognostic factors using Student's t-test. ADC was also correlated with histological grade using the Kruskal–Wallis test. Results: Mean ADC of IDC NOS was significantly lower than that of DCIS (p<0.001). However, the mean ADC of histological grade of IDC NOS was not significantly different (p=0.564). Mean ADC of oestrogen receptor (ER)-positive or progesterone receptor (PR)-positive cancer was significantly lower than that of ER-negativ...
152 citations
TL;DR: Improved survival outcomes consistent with those published in the literature for the addition of concurrent and adjuvant TMZ to radical RT for the treatment of GBM are demonstrated.
Abstract: Objective Glioblastoma multiforme (GBM) accounts for up to 60% of all malignant primary brain tumours in adults, occurring in 2–3 cases per 100 000 in Europe and North America. In 2005, a Phase III clinical trial demonstrated a significant improvement in survival over 2, and subsequently 5, years with the addition of concurrent and adjuvant temozolomide (TMZ) to radical radiotherapy (RT). The aim of this study was to investigate if the demonstrated improved survival in the literature translated to clinical practice. Methods This was a retrospective study including all patients with histologically proven GBM diagnosed from 1999 to 2008 and treated with adjuvant RT at our institution. A total of 273 patients were identified. Statistical analysis was carried out using SPSS® v.18 (SPSS, Chicago, IL). Results The median survival for the whole group (n=273) over the 10-year period was 7.6 months (95% confidence interval 6.7–8.4 months). Overall, the cumulative probability of survival at 1 and 2 years was 31.5% ...
152 citations
TL;DR: It is imperative that dental CBCT examinations on children should be fully justified over conventional X-ray imaging and that dose optimisation by field of view collimation is particularly important in young children.
Abstract: Objectives: Cone beam CT (CBCT) is an emerging X-ray technology applied in dentomaxillofacial imaging. Previous published studies have estimated the effective dose and radiation risks using adult anthropomorphic phantoms for a wide range of CBCT units and imaging protocols. Methods: Measurements were made five dental CBCT units for a range of imaging protocols, using 10-year-old and adolescent phantoms and thermoluminescent dosimeters. The purpose of the study was to estimate paediatric organ and effective doses from dental CBCT. Results: The average effective doses to the 10-year-old and adolescent phantoms were 116 mSv and 79 mSv, respectively, which are similar to adult doses. The salivary glands received the highest organ dose and there was a fourfold increase in the thyroid dose of the 10-year-old relative to that of the adolescent because of its smaller size. The remainder tissues and salivary and thyroid glands contributed most significantly to the effective dose for a 10-year-old, whereas for an adolescent the remainder tissues and the salivary glands contributed the most significantly. It was found that the percentage attributable lifetime mortality risks were 0.002% and 0.001% for a 10-year-old and an adolescent patient, respectively, which are considerably higher than the risk to an adult having received the same doses. Conclusion: It is therefore imperative that dental CBCT examinations on children should be fully justified over conventional X-ray imaging and that dose optimisation by field of view collimation is particularly important in young children.
TL;DR: The multidetector CT findings of LPD are heterogeneous, thereby reflecting the wide spectrum of clinical manifestations of these entities and a demonstration of the breadth of MDCT patterns within this disease spectrum.
Abstract: Pulmonary lymphoproliferative disorders (LPD) are characterised by abnormal proliferation of indigenous cell lines or infiltration of lung parenchyma by lymphoid cells. They encompass a wide spectrum of focal or diffuse abnormalities, which may be classified as reactive or neoplastic on the basis of cellular morphology and clonality. The spectrum of reactive disorders results primarily from antigenic stimulation of bronchial mucosa-associated lymphoid tissue (MALT) and comprises three main entities: follicular bronchiolitis, lymphoid interstitial pneumonia and (more rarely) nodular lymphoid hyperplasia. Primary parenchymal neoplasms are most commonly extranodal marginal zone lymphomas of MALT origin (MALT lymphomas), followed by diffuse large B-cell lymphomas (DLBCLs) and lymphomatoid granulomatosis (LYG). Secondary lymphomatous parenchymal neoplasms (both Hodgkin and non-Hodgkin lymphomas) are far more prevalent than primary neoplasms. Acquired immune deficiency syndrome (AIDS)-related lymphoma (ARL) and post-transplantation lymphoproliferative disorder (PTLD) may also primarily affect the lung parenchyma. Modern advances in treatments for AIDS and transplant medicine are associated with an increase in the incidence of LPD and have heightened the need to understand the range of imaging appearance of these diseases. The multidetector CT (MDCT) findings of LPD are heterogeneous, thereby reflecting the wide spectrum of clinical manifestations of these entities. Understanding the spectrum of LPD and the various imaging manifestations is crucial because the radiologist is often the first one to suggest the diagnosis and has a pivotal role in differentiating these diseases. The current concepts of LPD are discussed together with a demonstration of the breadth of MDCT patterns within this disease spectrum.
TL;DR: Baseline figures for Irish CT DRLs are provided on the most frequently performed CT examinations, and wide variations in mean doses across sites suggest a large potential for optimisation of examinations.
Abstract: Objective: To propose Irish CT diagnostic reference levels (DRLs) by collecting radiation doses for the most commonly performed CT examinations. Methods: A pilot study investigated the most frequent CT examinations. 40 CT sites were then asked to complete a survey booklet to allow the recording of CT parameters for each of 9 CT examinations during a 12-week period. Dose data [CT volume index (CTDIvol) and dose–length product (DLP)] on a minimum of 10 average-sized patients in each category were recorded to calculate a mean site CTDIvol and DLP value. The rounded 75th percentile was used to calculate a DRL for each site and the country by compiling all results. Results are compared with international DRL data. Results: Data were collected for 3305 patients. 30 sites responded with data for 34 scanners, representing 54% of the national total. All equipment had multislice capability (2–128 slices). DRLs are proposed using CTDIvol (mGy) and DLP (mGy cm) for CT head (66/58 and 940, respectively), sinuses (16 and 210, respectively), cervical spine (19 and 420, respectively), thorax (9/11 and 390, respectively), high resolution CT (7 and 280, respectively), CT pulmonary angiography (13 and 430, respectively), multiphase abdomen (13 and 1120, respectively), routine abdomen/pelvis (12 and 600, respectively) and trunk examinations (10/12 and 850, respectively). These values are lower than current DRLs and comparable to other international studies. Wide variations in mean doses are noted across sites. Conclusions: Baseline figures for Irish CT DRLs are provided on the most frequently performed CT examinations. The variations in dose between CT departments as well as between identical scanners suggest a large potential for optimisation of examinations.
TL;DR: Combined 2D+3D mammography prolongs image acquisition time and screen-reading time (at initial implementation), and appears to be associated with improved screening accuracy.
Abstract: 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...
TL;DR: The spectrum of neoplastic and non-neoplastic diseases that may show the reversed halo sign and offer helpful clues for assisting in the differential diagnosis is presented.
Abstract: The reversed halo sign is characterised by a central ground-glass opacity surrounded by denser air-space consolidation in the shape of a crescent or a ring. It was first described on high-resolution CT as being specific for cryptogenic organising pneumonia. Since then, the reversed halo sign has been reported in association with a wide range of pulmonary diseases, including invasive pulmonary fungal infections, paracoccidioidomycosis, pneumocystis pneumonia, tuberculosis, community-acquired pneumonia, lymphomatoid granulomatosis, Wegener granulomatosis, lipoid pneumonia and sarcoidosis. It is also seen in pulmonary neoplasms and infarction, and following radiation therapy and radiofrequency ablation of pulmonary malignancies. In this article, we present the spectrum of neoplastic and non-neoplastic diseases that may show the reversed halo sign and offer helpful clues for assisting in the differential diagnosis. By integrating the patient's clinical history with the presence of the reversed halo sign and other accompanying radiological findings, the radiologist should be able to narrow the differential diagnosis substantially, and may be able to provide a presumptive final diagnosis, which may obviate the need for biopsy in selected cases, especially in the immunosuppressed population.
TL;DR: In this article, the authors evaluated reader variability in screening mammograms according to the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) assessment and breast density categories.
Abstract: Objective The aim of this study was to evaluate reader variability in screening mammograms according to the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) assessment and breast density categories. Methods A stratified random sample of 100 mammograms was selected from a population-based breast cancer screening programme in Barcelona, Spain: 13 histopathologically confirmed breast cancers and 51 with true-negative and 36 with false-positive results. 21 expert radiologists from radiological units of breast cancer screening programmes in Catalonia, Spain, reviewed the mammography images twice within a 6-month interval. The readers described each mammography using BI-RADS assessment and breast density categories. Inter- and intraradiologist agreement was assessed using percentage of concordance and the kappa (κ) statistic. Results Fair interobserver agreement was observed for the BI-RADS assessment [κ=0.37, 95% confidence interval (CI) 0.36–0.38]. When the categories were coll...
TL;DR: Significant changes in ADC in patients responding to treatment are confirmed and indirect evidence from two-point Dixon MRI suggests that these changes are influenced by changes in marrow fat.
Abstract: 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 m...
TL;DR: Diagnostic accuracy studies of CT, MRI, ultrasound or PET/CT for staging of hilar cholangiocarcinoma are sparse and have moderate methodological quality, but primarily concern CT, which has an acceptable accuracy for assessment of ductal extent, portal vein and hepatic artery involvement, but low sensitivity for nodal status.
Abstract: Objective To obtain diagnostic performance values of CT, MRI, ultrasound and 18-fludeoxyglucose positron emission tomography (PET)/CT for staging of hilar cholangiocarcinoma. Methods A comprehensive systematic search was performed for articles published up to March 2011 that fulfilled the inclusion criteria. Study quality was assessed with the quality assessment of diagnostic accuracy studies tool. Results 16 articles (448 patients) were included that evaluated CT (n=11), MRI (n=3), ultrasound (n=3), or PET/CT (n=1). Overall, their quality was moderate. The accuracy estimates for evaluation of CT for ductal extent of the tumour was 86%. The sensitivity and specificity estimates of CT were 89% and 92% for evaluation of portal vein involvement, 83% and 93% for hepatic artery involvement, and 61% and 88% for lymph node involvement, respectively. Data were too limited for adequate comparisons of the different techniques. Conclusion Diagnostic accuracy studies of CT, MRI, ultrasound or PET/CT for staging of hi...
TL;DR: This review identifies five distinct types of radiation damage and classifies the radioprotective agents into five relevant categories, and stresses the necessity of establishing and funding central committees that guide systematic clinical research into evaluating the novel agents revealed in the era of molecular medicine.
Abstract: Exposure to ionising radiation results in mutagenesis and cell death, and the clinical manifestations depend on the dose and the involved body area. Reducing carcinogenesis in patients treated with radiotherapy, exposed to diagnostic radiation or who are in certain professional groups is mandatory. The prevention or treatment of early and late radiotherapy effects would improve quality of life and increase cancer curability by intensifying therapies. Experimental and clinical data have given rise to new concepts and a large pool of chemical and molecular agents that could be effective in the protection and treatment of radiation damage. To date, amifostine is the only drug recommended as an effective radioprotectant. This review identifies five distinct types of radiation damage (I, cellular depletion; II, reactive gene activation; III, tissue disorganisation; IV, stochastic effects; V, bystander effects) and classifies the radioprotective agents into five relevant categories (A, protectants against all types of radiation effects; B, death pathway modulators; C, blockers of inflammation, chemotaxis and autocrine/paracrine pathways; D, antimutagenic keepers of genomic integrity; E, agents that block bystander effects). The necessity of establishing and funding central committees that guide systematic clinical research into evaluating the novel agents revealed in the era of molecular medicine is stressed.
TL;DR: 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 are illustrated.
Abstract: 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.
TL;DR: MRI is a safe, accurate and precise imaging modality for measuring both visceral and subcutaneous adipose tissue, making it a favourable alternative to CT for quantification of these adipose depots.
Abstract: Objective CT is considered the gold standard imaging modality for measurement of visceral adipose tissue area. However, as CT imaging exposes subjects to ionising radiation, a comparable imaging technique without this exposure is desirable, such as MRI. Therefore, we compared the agreement of measures of visceral adipose tissue and subcutaneous adipose tissue area from single-slice images obtained at the umbilicus using a 3 T MRI scanner with single-slice images obtained via CT scan. Methods 64 images were obtained from 27 subjects who underwent MRI and CT scanning on the same day, after 10–12 hours of fasting. Visceral and subcutaneous adipose tissue depots were manually separated and quantified using a multimodality image-processing software program. Results We found good agreement between CT and MRI for the measurement of both visceral adipose tissue and subcutaneous adipose tissue. Bland–Altman difference analysis demonstrated a mean bias of −2.9% (as a portion of total abdominal area) for visceral ad...
TL;DR: The first epidemiological study to show an excess incidence of leukaemia and brain cancer in children and adolescents who had received CT scans is published in The Lancet, providing human epidemiological data supporting the notion that doses as low as those involved in CT scans can induce a detectable cancer incidence in humans.
Abstract: In 2008, as part of the BJR Hounsfield review series, we published “Cancer risks from diagnostic radiology” [1], which included an estimate of the lifetime cancer risk as a function of age at exposure, from the radiation associated with a head CT scan and an abdominal CT scan. These risk estimates were based on age-specific, gender-specific and organ-specific cancer risks derived primarily from the Japanese A-bomb survivors [2,3]. We estimated that these risk estimates were probably good to within a factor of three, in both directions.
Now, Pearce et al [4] have published in The Lancet the first epidemiological study to show an excess incidence of leukaemia and brain cancer in children and adolescents who had received CT scans. The authors studied a cohort of 178 604 children who underwent a CT scan between 1985 and 2002 in various hospitals in the UK, estimated organ doses involved, and then identified subsequent malignancies via linkage to the National Health Service Central Registry. The average follow-up time was a little under 10 years. This study was possible in the UK because of the available electronic records, but would be incredibly difficult to repeat in many other countries, including the USA. It is a large, well-conducted, record-based cohort study, and so deserves attention.
We know from the ongoing study of the Japanese A-bomb survivors that to obtain lifetime risk estimates the irradiated population needs to be studied for at least 50–60 years! To focus on leukaemia (and to an extent brain cancer) in children is effectively a shortcut because these malignancies have a short latent period in children. For example, the great majority of radiation-induced leukaemias appear within 10 years of exposure.
Pearce et al [4] reported that the risk of leukaemia was positively associated with estimated doses delivered by CT scans to the red bone marrow, as was the risk of brain cancers associated with estimated doses delivered by CT scans to the brain. Quantitatively, having two to three head scans triples the estimated risk of brain cancer, while five to ten head scans triples the estimated risk of leukaemia. Of course, these very small radiation risks must be viewed in the context of the extraordinary clinical usefulness of CT in a great variety of clinical settings.
Human epidemiology trumps all calculations and estimates, of course. So how do these new data impact our review [1] of what was known in 2008?
The new data confirm that the cancer risk associated with the radiation from a CT scan is very small, but not zero. It can be detected in a cohort of a few hundred thousand children. The individual risk is very small and is far outweighed by the benefit of the diagnosis, provided the scan is clinically justified. The new study is important because it provides human epidemiological data supporting the notion that doses as low as those involved in CT scans can induce a detectable cancer incidence in humans.
Our estimated lifetime risk of leukaemia from one paediatric head CT scan, based on the A-bomb data, was about 1 in 10 000 [1,2]. The estimate of Pearce et al [4] based on the epidemiological data was also about 1 in 10 000. Good agreement!
Our estimate of the lifetime risk of brain cancer from a paediatric head CT scan was about 1 in 2000 [1,2]. The risk estimate of Pearce et al [4] was 1 in 10 000, to the end of follow-up. A big difference here, but there is a simple explanation: the average length of follow-up in the Pearce et al paper is only about 8–10 years. The study of children epilated with X-rays for the treatment of tinea capitis [5] shows that only about 10% of the final lifetime risk of brain cancer shows up in the first decade after irradiation. If this factor of 10 is corrected for, the lifetime brain tumour risk estimate would be about 1 in 1000, agreeing reasonably well with the A-bomb-derived estimate of 1 in 2000. The reason for the difference may be that some of the CT scans were performed on children with early symptoms of a brain tumour that was only diagnosed much later. The authors tried to avoid this problem as far as possible by excluding brain tumours occurring within 5 years of the scan.
In order to get a result in a relatively short time, Pearce et al [4] focused on leukaemia and brain cancer in irradiated children. It is therefore quite a limited study. A knowledge of the spectrum of all the other solid cancers after paediatric CT, and all malignancies after adult CT, must await further studies, and these are likely to take many years and involve significant difficulties. There are many other groups studying (or planning to study) national cohorts of CT patients. Some will have a longer follow-up and larger numbers, so they may well contribute further information about cancer induction at low radiation doses. However, they all suffer from the same limitation; namely, that these efforts focus on paediatric CT. They will not provide data relevant to the vast majority of CT scans, given that at least 90% of all CT scans are in adults.
Meanwhile, for most CT scans, we have estimates based only on organ doses and the Japanese A-bomb data. These estimates have proved to be in reasonable agreement with the epidemiological data in the few cases where it is possible to check them (i.e. for leukaemia and brain cancer from a head CT scan). Based on the Japanese A-bomb data, the risk estimates for abdominal CT scans are about 10 times larger than for head CT scans because of all of the radiogenic organs located in the trunk of the body, and, as pointed out above, there are no epidemiological data in sight to check these numbers. Estimates are all we will have for the foreseeable future, but even if they are only approximate, they are important at a time of increasing concern about the major increase in the collective dose from medical radiation over the past two decades, with much of it due to the burgeoning use of CT. The current estimate is almost 5 million CT scans per year in the UK, and about 85 million per year in the United States. The Pearce et al study [4] is an important piece of additional evidence to show that low doses of radiation do carry some (admittedly small) risk, which must be taken into account.
TL;DR: The international variations in practice and options available for S/GA for imaging children under general anaesthesia vary from country to country, but the ultimate goal of S/ GA in radiology remains the same; namely, to provide safety and comfort for the patients.
Abstract: Objectives In this article we will give a comprehensive literature review on sedation/general anaesthesia (S/GA) and discuss the international variations in practice and options available for S/GA for imaging children. Methods The key articles were obtained primarily from PubMed, MEDLINE, ERIC, NHS Evidence and The Cochrane Library. Results Recently, paediatric radiology has seen a surge of diagnostic and therapeutic procedures, some of which require children to be still and compliant for up to 1 h. It is difficult and sometimes even impossible to obtain quick and high-quality images without employing sedating techniques in certain children. As with any medical procedure, S/GA in radiological practice is not without risks and can have potentially disastrous consequences if mismanaged. In order to reduce any complications and practice safety in radiological units, it is imperative to carry out pre-sedation assessments of children, obtain parental/guardian consent, monitor them closely before, during and af...
TL;DR: The aim of this review is to illustrate the potential of different and newer ultrasound techniques beyond conventional B-mode imaging, including colour Doppler ultrasound, contrast-enhanced ultrasound (CEUS) and tissue elastography, in the characterisation of both benign and malignant intratesticular lesions.
Abstract: The aim of this review is to illustrate the potential of different and newer ultrasound techniques beyond conventional B-mode imaging, including colour Doppler ultrasound, contrast-enhanced ultrasound (CEUS) and tissue elastography, in the characterisation of both benign and malignant intratesticular lesions. Normally, testicular malignancies, either primary or secondary, demonstrate an increase in colour Doppler signal. However, there is a diversity of benign testicular lesions that may mimic testicular malignancies. The use of CEUS improves characterisation of testicular lesions, and confirms lack of vascularity in benign abnormalities such as epidermoid cysts, infarctions, abscesses and changes following trauma. Tissue elastography allows further evaluation of the cellular consistency of the abnormality. Familiarity with the appearances seen with these ultrasound techniques in both benign and malignant abnormalities should aid in improving confidence in arriving at the correct diagnosis.
TL;DR: The methods available to clinicians and radiologists that are used to assess skeletal muscle injury and the spectrum of muscle injuries sustained in the elite athlete population are discussed and illustrated.
Abstract: Injuries to muscle in the elite athlete are common and may be responsible for prolonged periods of loss of competitive activity. The implications for the athlete and his/her coach and team may be catastrophic if the injury occurs at a critical time in the athlete's diary. Imaging now plays a crucial role in diagnosis, prognostication and management of athletes with muscle injuries. This article discusses the methods available to clinicians and radiologists that are used to assess skeletal muscle injury. The spectrum of muscle injuries sustained in the elite athlete population is both discussed and illustrated.
TL;DR: Anatomical variants of the biliary tree with surgical significance are described, followed by comparison of CT and MR cholangiographies.
Abstract: Recent developments in imaging technology have enabled CT and MR cholangiopancreatography (MRCP) to provide minimally invasive alternatives to endoscopic retrograde cholangiopancreatography for the pre- and post-operative assessment of biliary disease. This article describes anatomical variants of the biliary tree with surgical significance, followed by comparison of CT and MR cholangiographies. Drip infusion cholangiography with CT (DIC-CT) enables high-resolution three-dimensional anatomical representation of very small bile ducts (e.g. aberrant branches, the caudate branch and the cystic duct), which are potential causes of surgical complications. The disadvantages of DIC-CT include the possibility of adverse reactions to biliary contrast media and insufficient depiction of bile ducts caused by liver dysfunction or obstructive jaundice. Conventional MRCP is a standard, non-invasive method for evaluating the biliary tree. MRCP provides useful information, especially regarding the extrahepatic bile ducts and dilated intrahepatic bile ducts. Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced MRCP may facilitate the evaluation of biliary structure and excretory function. Understanding the characteristics of each type of cholangiography is important to ensure sufficient perioperative evaluation of the biliary system.
TL;DR: Novel modalities including contrast-enhanced modes and elastography as well as fusion techniques for increasing the sensitivity of TRUS-guided prostate-targeted biopsies are discussed along with their role in the diagnosis and management of prostate cancer.
Abstract: Transrectal ultrasound (TRUS) was first developed in the 1970s. TRUS-guided biopsy, under local anaesthetic and prophylactic antibiotics, is now the most widely accepted method to diagnose prostate cancer. However, the sensitivity and specificity of greyscale TRUS in the detection of prostate cancer is low. Prostate cancer most commonly appears as a hypoechoic focal lesion in the peripheral zone on TRUS but the appearances are variable with considerable overlap with benign lesions. Because of the low accuracy of greyscale TRUS, TRUS-guided biopsies have become established in the acquisition of systematic biopsies from standard locations. The number of systematic biopsies has increased over the years, with 10-12 cores currently accepted as the minimum standard. This article describes the technique of TRUS and biopsy and its complications. Novel modalities including contrast-enhanced modes and elastography as well as fusion techniques for increasing the sensitivity of TRUS-guided prostate-targeted biopsies are discussed along with their role in the diagnosis and management of prostate cancer.
TL;DR: Adding DWI to T2 WI is helpful for detecting viable tumours after neoadjuvant CRT compared with T2WI alone or PET/CT in patients with locally advanced rectal cancer.
Abstract: Objectives: To evaluate the added value of diffusion-weighted imaging (DWI) in combination with T2 weighted imaging (T2WI) compared with T2WI alone or positron emission tomography (PET)/CT for detecting viable tumour after neoadjuvant chemoradiation therapy (CRT) in patients with locally advanced rectal cancer. Methods: 50 consecutive patients with locally advanced rectal cancer (≥T3 or lymph node positive) who underwent neoadjuvant CRT and subsequent surgery were enrolled in this retrospective study. All patients underwent 3.0 T rectal MRI and PET/CT after completing CRT. For qualitative analysis, two radiologists independently reviewed T2WI alone and DWI with T2WI over a 1-month interval. One nuclear medicine physician reviewed PET/CT images using a five-point scale. Diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for detecting viable tumour were assessed. For quantitative analysis, the apparent diffusion coefficients (ADCs) of the lesio...
TL;DR: The prevalence, clinical signs and radiological features of breast lymphoma were determined, and intramammary masses were the most commonly seen on mammography and CT, most lesions presented as circumscribed round or oval masses with moderate or high enhancement.
Abstract: Objectives: The purpose of this study was to determine the prevalence, clinical signs and radiological features of breast lymphoma. Methods: This is a retrospective review of 36 patients with breast lymphoma (22 primary and14secondary).35 patientswere femaleand1 wasmale; theirmedian agewas65years (range 24–88 years). In all patients, the diagnosis was confirmed histopathologically. Results: The prevalence of breast lymphoma was 1.6% of all identified cases with non-Hodgkin lymphoma and 0.5% of cases with breast cancer. B-cell lymphoma was found in 94% and T-cell lymphoma in 6%. 96 lesions were identified (2.7 per patient). The mean size was 15.8i8.3mm. The number of intramammary lesions was higher in secondary than in primary lymphoma. The size of the identified intramammary lesions was larger in primary than in secondary lymphoma. Clinically, 86% of the patients presented with solitary or multiple breast lumps. In 14%, breast involvement was diagnosed incidentally during staging examinations. Conclusion: On mammography, intramammary masses were the most commonly seen (27 patients, 82%). Architectural distortion occurred in three patients (9%). In three patients (9%), no abnormalities were found on mammography. On ultrasound, the identified lesions were homogeneously hypoechoic or heterogeneously mixed hypo- to hyperechoic. On MRI, the morphology of the lesions was variable. After intravenous administration of contrast medium, a marked inhomogeneous contrast enhancement was seen in most cases. On CT, most lesions presented as circumscribed round or oval masses with moderate or high enhancement.
TL;DR: A MEDLINE search and critically reviewed studies using the three imaging techniques in evaluating anal sphincter integrity and the need for technique standardisation, validation and reporting is of paramount importance.
Abstract: Endoanal ultrasound is now regarded as the gold standard for evaluating anal sphincter pathology in the investigation of anal incontinence. The advent of three-dimensional ultrasound has further improved our understanding of the two-dimensional technique. Endoanal ultrasound requires specialised equipment and its relative invasiveness has prompted clinicians to explore alternative imaging techniques. Transvaginal and transperineal ultrasound have been recently evaluated as alternative imaging modalities. However, the need for technique standardisation, validation and reporting is of paramount importance. We conducted a MEDLINE search (1950 to February 2010) and critically reviewed studies using the three imaging techniques in evaluating anal sphincter integrity.