Making computed tomography safer for patients with Crohn's disease.

Background and aims: Computed tomography (CT), often more accessible than magnetic resonance imaging (MRI), remains widely used though radiation exposure is an obvious disadvantage. We previously showed that modern CT technology can achieve over 70% reduction in radiation-dose without loss of accuracy. Here, we compare low- versus conventional-dose CT in patients with known Crohn's disease to assess clinical confidence and accuracy of the low-dose procedure in the semi-acute setting.Methods: A comparative study of low-dose CT with full iterative reconstruction (IR) versus conventional-dose CT was conducted in 50 consecutive outpatients with Crohn's disease. Clinicians were provided with the low-dose images and reports, whereas conventional-dose images were reviewed after 4 weeks.Results: The clinical question was adequately addressed with low-dose IR imaging in all cases. Complications of Crohn's were detected in 37/50 (74%) with no disagreement between low- and conventional-dose imaging. The effective radiation dose reduction was 76.5% (low-dose mean 2.15 mSv versus conventional-dose CT 6.99 mSv).Conclusion: Low-dose IR CT is safe and accurate for evaluating distribution and complications of known Crohn's disease in the outpatient setting. We propose that low-dose radiation imaging should be adopted as standard-of-care for the evaluation of Crohn's disease and an acceptable alternative to MR particularly in the acute setting. ClinicalTrials.gov: NCT03140306.

Computed tomography in cystic fibrosis lung disease: a focus on radiation exposure.

Thoracic computed tomography (CT) is the imaging reference method in the diagnosis, assessment and management of lung disease. In the setting of cystic fibrosis (CF), CT demonstrates increased sensitivity compared with pulmonary function tests and chest radiography, and findings correlate with clinical outcomes. Better understanding of the aetiology of CF lung disease indicates that even asymptomatic infants with CF can have irreversible pulmonary pathology. Surveillance and early diagnosis of lung disease in CF are important to preserve lung parenchyma and to optimise long-term outcomes. CF is associated with increased cumulative radiation exposure due to the requirement for repeated imaging from a young age. Radiation dose optimisation, important for the safe use of CT in children with CF, is best achieved in a team environment where paediatric radiologists work closely with paediatric respiratory physicians, physicists and radiography technicians to achieve the best patient outcomes. Despite the radiation doses incurred, CT remains a vital imaging tool in children with CF. Radiologists with special interests in CT dose optimisation and respiratory disease are key to the appropriate use of CT in paediatric imaging. Paediatric radiologists strive to minimise radiation dose to children whilst providing the best possible assessment of lung disease.

Fast acquisition abdominal MRI study for the investigation of suspected acute appendicitis in paediatric patients.

OBJECTIVES: To assess the diagnostic accuracy of fast acquisition MRI in suspected cases of paediatric appendicitis presenting to a tertiary referral hospital. MATERIALS AND METHODS: A prospective study was undertaken between May and October 2017 of 52 children who presented with suspected appendicitis and were referred for an abdominal ultrasound. All patients included in this study received both an abdominal ultrasound and five-sequence MRI consisting of axial and coronal gradient echo T2 scans, fat-saturated SSFSE and a diffusion-weighted scan. Participants were randomised into groups of MRI with breath-holds or MRI with free breathing. A patient satisfaction survey was also carried out. Histopathology findings, where available, were used as a gold standard for the purposes of data analysis. Statistical analysis was performed, and p values < 0.05 were considered statistically significant. RESULTS: Ultrasound had a sensitivity and specificity of 25% and 92.9%, respectively. MRI with breath-hold had a sensitivity and specificity of 81.8% and 66.7%, respectively, whilst MRI with free breathing was superior with sensitivity and specificity of 92.3% and 84.2%, respectively. MRI with free breathing was also more time efficient (p < 0.0001). Group statistics were comparable (p < 0.05). CONCLUSIONS: The use of fast acquisition MRI protocols, particularly free breathing sequences, for patients admitted with suspected appendicitis can result in faster diagnosis, treatment and discharge. It also has a statistically significant diagnostic advantage over ultrasound. Additionally, the higher specificity of MR can reduce the number of negative appendectomies performed in tertiary centres.

Low-dose CT imaging of the acute abdomen using model-based iterative reconstruction: a prospective study.

OBJECTIVES: Performance of a modified abdominopelvic CT protocol reconstructed using full iterative reconstruction (IR) was assessed for imaging patients presenting with acute abdominal symptoms. MATERIALS AND METHODS: Fifty-seven patients (17 male, 40 female; mean age of 56.5 ± 8 years) were prospectively studied. Low-dose (LD) and conventional-dose (CD) CTs were contemporaneously acquired between November 2015 and March 2016. The LD and CD protocols imparted radiation exposures approximating 10-20% and 80-90% those of routine abdominopelvic CT, respectively. The LD images were reconstructed with model-based iterative reconstruction (MBIR), and CD images with hybrid IR (40% adaptive statistical iterative reconstruction (ASIR)). Image quality was assessed quantitatively and qualitatively. Independent clinical interpretations were performed with a 6-week delay between reviews. RESULTS: A 74.7% mean radiation dose reduction was achieved: LD effective dose (ED) 2.38 ± 1.78 mSv (size-specific dose estimate (SSDE) 3.77 ± 1.97 mGy); CD ED 7.04 ± 4.89 mSv (SSDE 10.74 ± 5.5 mGy). LD-MBIR images had significantly lower objective and subjective image noise compared with CD-ASIR (p < 0.0001). Noise reduction for LD-MBIR studies was greater for patients with BMI < 25 kg/m2 than those with BMI ≥ 25 kg/m2 (5.36 ± 3.2 Hounsfield units (HU) vs. 4.05 ± 3.1 HU, p < 0.0001). CD-ASIR studies had significantly better contrast resolution, and diagnostic acceptability (p < 0.0001 for all). LD-MBIR studies had significantly lower streak artifact (p < 0.0001). There was no difference in sensitivity for primary findings between the low-dose and conventional protocols with the exception of one case of enteritis. CONCLUSIONS: Low-dose abdominopelvic CT performed with MBIR is a feasible radiation dose reduction strategy for imaging patients presenting with acute abdominal pain.

Low-Dose Computed Tomography for the Optimization of Radiation Dose Exposure in Patients with Crohn's Disease.

Magnetic resonance imaging (MRI) is the mainstay method for the radiological imaging of the small bowel in patients with inflammatory bowel disease without the use of ionizing radiation. There are circumstances where imaging using ionizing radiation is required, particularly in the acute setting. This usually takes the form of computed tomography (CT). There has been a significant increase in the utilization of computed tomography (CT) for patients with Crohn's disease as patients are frequently diagnosed at a relatively young age and require repeated imaging. Between seven and eleven percent of patients with IBD are exposed to high cumulative effective radiation doses (CEDs) (>35-75 mSv), mostly patients with Crohn's disease (Newnham E 2007, Levi Z 2009, Hou JK 2014, Estay C 2015). This is primarily due to the more widespread and repeated use of CT, which accounts for 77% of radiation dose exposure amongst patients with Crohn's disease (Desmond et al., 2008). Reports of the projected cancer risks from the increasing CT use (Berrington et al., 2007) have led to increased patient awareness regarding the potential health risks from ionizing radiation (Coakley et al., 2011). Our responsibilities as physicians caring for these patients include education regarding radiation risk and, when an investigation that utilizes ionizing radiation is required, to keep radiation doses as low as reasonably achievable: the "ALARA" principle. Recent advances in CT technology have facilitated substantial radiation dose reductions in many clinical settings, and several studies have demonstrated significantly decreased radiation doses in Crohn's disease patients while maintaining diagnostic image quality. However, there is a balance to be struck between reducing radiation exposure and maintaining satisfactory image quality; if radiation dose is reduced excessively, the resulting CT images can be of poor quality and may be nondiagnostic. In this paper, we summarize the available evidence related to imaging of Crohn's disease, radiation exposure, and risk, and we report recent advances in low-dose CT technology that have particular relevance.

Review of the role of abdominal imaging in irritable bowel syndrome.

The role of radiologic imaging in the investigation of irritable bowel syndrome (IBS) remains a subject of debate and there is some evidence, from recent studies of utilization of imaging in IBS, which focused on associated costs and radiation exposure, that imaging is being used relatively widely in these patients. This review aims to assess current best evidence to accurately define the role of radiologic imaging in IBS patients. Primary and secondary literature searches were performed. Evidence suggests that the lack of "red flag" or alarm features in IBS patients should reassure the clinician that the diagnosis of IBS is correct and United States and United Kingdom guidelines recommend no radiologic imaging for IBS patients if alarm features are not present. In patients presenting with IBS symptoms and alarm features, radiologic testing may be used to exclude an alternative diagnosis and the imaging modality should be chosen based on the most likely alternative diagnosis.

Using body mass index to estimate individualised patient radiation dose in abdominal computed tomography.

BACKGROUND: The size-specific dose estimate (SSDE) is a dose-related metrics that incorporates patient size into its calculation. It is usually derived from the volume computed tomography dose index (CTDIvol) by applying a conversion factor determined from manually measured anteroposterior and lateral skin-to-skin patient diameters at the midslice level on computed tomography (CT) localiser images, an awkward, time-consuming, and not highly reproducible technique. The objective of this study was to evaluate the potential for the use of body mass index (BMI) as a size-related metrics alternative to the midslice effective diameter (DE) to obtain a size-specific dose (SSDE) in abdominal CT. METHODS: In this retrospective study of patients who underwent abdominal CT for the investigation of inflammatory bowel disease, the DE was measured on the midslice level on CT-localiser images of each patient. This was correlated with patient BMI and the linear regression equation relating the quantities was calculated. The ratio between the internal and the external abdominal diameters (DRATIO) was also measured to assess correlation with radiation dose. Pearson correlation analysis and linear regression models were used. RESULTS: There was good correlation between DE and patient BMI (r = 0.88). An equation allowing calculation of DE from BMI was calculated by linear regression analysis as follows: DE = 0.76 (BMI) + 9.4. A weak correlation between radiation dose and DRATIO was demonstrated (r = 0.45). CONCLUSIONS: Patient BMI can be used to accurately estimate DE, obviating the need to measure anteroposterior and lateral diameters in order to calculate a SSDE for abdominal CT.

The impact of sarcopenia and myosteatosis on postoperative outcomes in patients with inflammatory bowel disease.

BACKGROUND: Inflammatory bowel disease (IBD) is a relatively common disorder with significant associated morbidity. Sarcopenia and myosteatosis are associated with adverse postoperative outcomes. This study investigated outcomes in IBD patients undergoing surgical resection relative to the presence of sarcopenia and myosteatosis. METHODS: A retrospective analysis of a prospectively maintained surgical database was conducted. All patients undergoing elective or emergency resection for IBD between 2011 and 2016, with a contemporaneous perioperative computed tomography (CT) scan, were included. Patient demographics, clinical and biochemical measurements were collected. Skeletal muscle index and attenuation were measured on perioperative CT scans using Osirix version 5.6.1. Univariate and multivariate regression analysis was used to identify risk factors for adverse postoperative outcomes. RESULTS: Seventy-seven patients (46 male, 31 female; mean age 42 years, range 20-80 years) were included. Thirty patients (30%) had sarcopenia and 26 (34%) had myosteatosis. Myosteatosis was significantly associated with increased hospital stay postoperatively (9 versus 13 days). Sarcopenia and myosteatosis were associated with hospital readmission within 30 days on univariate analysis. Multivariate regression analysis demonstrated an independent association between myosteatosis and hospital readmission. Sixteen patients (21%) had a clinically relevant postoperative complication, but an association with sarcopenia and myosteatosis was not observed. A neutrophil-lymphocyte ratio greater than 5 was predictive of clinically relevant postoperative complications on multivariate regression analysis. CONCLUSIONS: Myosteatosis was associated with increased hospital stay and increased 30-day hospital readmission rates on multivariate regression analysis. Sarcopenia and myosteatosis in IBD were not associated with clinically relevant postoperative complications.

Sarcopenia and Post-Operative Morbidity and Mortality in Patients with Gastric Cancer.

PURPOSE: Surgical resection for gastric adenocarcinoma is associated with significant post-operative morbidity and mortality. The aim of this study was to assess the prognostic significance of sarcopenia in patients undergoing resection for gastric adenocarcinoma with respect to post-operative morbidity and survival. MATERIALS AND METHODS: A retrospective analysis was conducted on a cohort of consecutive patients who underwent surgical resection for gastric adenocarcinoma between 2008 and 2014. Patient demographics, radiological parameters, and pathological data were collected. OsiriX software (Pixmeo) was used to measure skeletal muscle area, which was normalized for height to calculate skeletal muscle index. RESULTS: A total of 56 patients (41 male, 15 female; mean age, 68.4 ± 11.9 years) met the inclusion criteria. Of these, 36% (20 of 56) of the patients were sarcopenic pre-operatively. Both sarcopenic and non-sarcopenic patient groups were equally matched with the exception of weight and body mass index (P=0.036 and 0.001, respectively). Sarcopenia was associated with a decreased overall survival (log-rank P=0.003) and was an adverse prognostic predictor of overall survival in multivariate analysis (hazard ratio, 10.915; P=0.001). Sarcopenia was a predictor of serious in-hospital complications in multivariate analysis (odds ratio, 3.508; P=0.042). CONCLUSIONS: In patients undergoing curative resection for gastric cancer, there was a statistically significant association between sarcopenia and both decreased overall survival and serious post-operative complications. The measurement and reporting of skeletal muscle index on pre-operative computed tomography should be considered.

A comparison of clinical- and patient-reported outcomes of the cemented ATTUNE and PFC sigma fixed bearing cruciate sacrificing knee systems in patients who underwent total knee replacement with both prostheses in opposite knees.

BACKGROUND: The ATTUNE Knee by DePuy Synthes was introduced in 2013. It is designed to provide better range of motion and address patient-reported instability. The PFC Sigma Knee, an earlier prosthesis by DePuy Synthes, is a common knee replacement with a strong clinical track record. Our aim is to compare the outcomes after primary total knee replacement for end-stage knee osteoarthritis of the PFC and ATTUNE knee systems in 21 patients who each have prosthesis in opposite knees using WOMAC, Oxford Knee and SF-12 scores and evaluation of range of motion. METHODS: A review was carried out on 21 patients who underwent primary total knee replacement with both the ATTUNE and PFC knee systems. These were staged operations performed in the same institution and by the same surgeon. All cases were followed up for a minimum of 6 months. WOMAC, Oxford Knee and SF-12 scores, as well as knee range of motion were recorded preoperatively and at 6 months postoperatively. RESULTS: There was a significant difference in pre- to 6-month post-operative outcomes in PFC and ATTUNE groups with regard to improvement in range of motion (10° ± 8 and 13° ± 11, respectively). There was also a significant improvement in WOMAC scores (PFC group) and Oxford Knee Scores (ATTUNE group) (8.9 ± 7.7 and 12.1 ± 8.4, respectively). There was a significant improvement in SF-12 Score in both groups (10.1 ± 9.3 for PFC and 15.8 ± 13.3 for ATTUNE). The minimum clinically important difference (MCID) in scoring systems at 6 months was reached by 6 patients in the PFC group and 12 in the ATTUNE group. CONCLUSION: A significant difference was demonstrated in clinical outcome at 6 months postoperatively between PFC and ATTUNE knee systems in patients who underwent total knee arthroplasty with both prostheses. Superior results were recorded for the ATTUNE knee system.