A prospective feasibility study of sub-millisievert abdominopelvic CT using iterative reconstruction in Crohn's disease.

OBJECTIVE: Iterative reconstruction (IR) allows diagnostic CT imaging with less radiation exposure than filtered back projection (FBP). We studied an IR low-dose CT abdomen/pelvis (LDCTAP) protocol, designed to image at an effective dose (ED) approximating 1 mSv in patients with Crohn's disease (CD). METHODS: Forty patients, mean age 37 ± 13.4 years (range 17-69), with CD underwent two synchronous CT protocols (conventional-dose (CDCTAP) and LDCTAP). CDCTAP and LDCTAP images were compared for diagnostic acceptability, yield, image quality and ED (in millisieverts). The optimal level of IR for LDCTAP was also studied. RESULTS: LDCTAP yielded a mean ED of 1.3 ± 0.8 mSv compared with 4.7 ± 2.9 mSv for CDCTAP, reducing ED by 73.7 ± 3.3 % (mean dose reduction, 3.5 ± 2.1 mSv; P < 0.001) and dose length product by 73.6 ± 2.6 % (P < 0.001). Sub-millisievert (0.84 mSv) imaging was performed for patients with a body mass index (BMI) less than 25 (i.e. 63 % of our cohort). LDCTAP resulted in increased image noise and reduced diagnostic acceptability compared with CDCTAP despite use of IR, but detection of extra-luminal complications was comparable. CONCLUSION: Patients with suspected active CD can be adequately imaged using LDCTAP, yielding comparable information regarding extent, activity and complications of CD compared with CDCTAP, but with 74 % less dose. LDCTAP at doses equivalent to that of two abdominal radiographs represents a feasible alternative to CDCTAP. KEY POINTS: • Radiation dose is a concern when imaging patients with Crohn's disease. • New techniques allow low-dose abdominopelvic CT with acceptable image quality. • Using hybrid iterative reconstruction, its diagnostic yield compares well with that of conventional CT. • Sub-millisievert CT of patients with Crohn's disease appears technically and clinically feasible.

Computed tomography assessment of intestinal gas volumes in functional gastrointestinal disorders.

BACKGROUND/AIMS: Many patients with functional gastrointestinal disorders (FGIDs) rank sensations of bloating and distension among their most debilitating symptoms. Previous studies that have examined intestinal gas volume (IGV) in patients with FGIDs have employed a variety of invasive and imaging techniques. These studies are limited by small numbers and have shown conflicting results. The aim of our study was to estimate, using CT of the abdomen and pelvis (CTAP), IGV in patients attending FGID clinic and to compare IGV in patients with and without FGID. METHODS: All CTAP (n = 312) performed on patients (n = 207) attending a specialized FGID clinic over 10-year period were included in this study. Patients were classified into one of 3 groups according to the established clinical grading system, as organic gastrointestinal disorder (OGID, ie, patients with an organic non-functional disorder, n = 84), FGID (n = 36) or organic and functional gastrointestinal disorder (OFGID, ie, patients with an organic and a functional disorder, n = 87). Two independent readers blinded to the diagnostic group calculated IGV using threshold based 3D region growing with OsiriX. RESULTS: Median IGVs for the FGID, OGID, and OFGID groups were 197.6, 220.6 and 155.0 mL, respectively. Stepwise linear regression revealed age at study, gender, and calculated body mass index to predict the log IGV with an r(2) of 0.116, and P < 0.001. There was a significant positive correlation between age and IGV in OGID (Spearman's = 0.253, P = 0.02) but this correlation was non-significant in the other groups. CONCLUSIONS: Although bloating is a classic symptom in FGID patients, IGV may not be increased compared with OGID and OFGID patients.

Evaluation of the efficacy and safety of percutaneous biopsy of lung.

INTRODUCTION: Percutanous needle biopsy of the lung (PNBL), under image guidance, has established itself as a safe and effective minimally-invasive method of obtaining a tissue diagnosis of pulmonary lesions, for selected patients with suspected pathologic processes. The purpose of this study was to evaluate the diagnostic yield and safety of percutaneous core biopsy of the lung (PCBL) without Fine Needle Aspiration Biopsy (FNAB), with specific attention to potential risk factors that may predict post-biopsy pneumothorax. MATERIALS AND METHODS: A retrospective analysis of 75 consecutive PCBL procedures between January 2006 to March 2008 involving 72 patients with a documented pulmonary nodule or mass lesion on CT scan of Thorax. The study population included 38 males (52.8%) and 34 females (47.2%) aged 20-85 years (mean age 63.6 years). A co-axial cutting system with a 19-gauge outer needle and a 20-gauge inner automated cutting needle (Temno, Allegiance Healthcare Corporation, Ohio, USA) was used in all patients. RESULTS: Lesions varied in size from 0.7cm to 10.7cm (mean maximum trans-axial diameter 3.1cm). The mean number of core biopsy samples obtained was 3.1 (range 1-5). Of the 75 PCBL procedures, 71 yielded specimens adequate for histopathologic evaluation, consistent with a technical success rate of 95%. Malignancy was detected in 48 specimens (64%) and benign diagnoses were identified in 23 specimens (31%). As mentioned, 4 specimens (5%) were nondiagnostic. The most common biopsy-induced complication was pneumothorax, occurring in 15 patients (20%), with 4 (5.3%) requiring thoracostomy tube placement. CONCLUSION: PCBL without FNAB, under CT fluoroscopy guidance, has an excellent diagnostic accuracy in obtaining a conclusive histologic diagnosis of thoracic lesions and is comparable to FNAB in terms of safety and rates of occurence of complications.

Minimization of Radiation Exposure due to Computed Tomography in Inflammatory Bowel Disease.

Patient awareness and concern regarding the potential health risks from ionizing radiation have peaked recently (Coakley et al., 2011) following widespread press and media coverage of the projected cancer risks from the increasing use of computed tomography (CT) (Berrington et al., 2007). The typical young and educated patient with inflammatory bowel disease (IBD) may in particular be conscious of his/her exposure to ionising radiation as a result of diagnostic imaging. Cumulative effective doses (CEDs) in patients with IBD have been reported as being high and are rising, primarily due to the more widespread and repeated use of CT (Desmond et al., 2008). Radiologists, technologists, and referring physicians have a responsibility to firstly counsel their patients accurately regarding the actual risks of ionizing radiation exposure; secondly to limit the use of those imaging modalities which involve ionising radiation to clinical situations where they are likely to change management; thirdly to ensure that a diagnostic quality imaging examination is acquired with lowest possible radiation exposure. In this paper, we synopsize available evidence related to radiation exposure and risk and we report advances in low-dose CT technology and examine the role for alternative imaging modalities such as ultrasonography or magnetic resonance imaging which avoid radiation exposure.

Is serum C-reactive protein a reliable predictor of abdomino-pelvic CT findings in the clinical setting of the non-traumatic acute abdomen?

The aim of this study was to determine if serum C-reactive protein (CRP), an acute phase reactant which exhibits a rapid rise in serum in inflammatory conditions, is a reliable predictor of abdomino-pelvic CT findings in the clinical setting of the non-traumatic acute abdomen. All patients presenting with symptoms of acute abdominal pain to a level-1 emergency department over a 12-month period were included. Patients with serum CRP measured on admission and within 24 h of the abdomino-pelvic CT scan were subselected and those with a history of recent surgery, malignancy, and inflammatory bowel disease were excluded (n = 241). CT findings were graded in consensus by two radiologists and visceral adipose volume and severity of adipose stranding were also assessed. Statistical analysis was performed using SPSS v17. Positive imaging findings were evident on 176 CTs (73 %). There were equal numbers of positive and negative CT scans in patients with low serum level of CRP (0-5 mg/L). As CRP level increased the proportion of positive CTs increased (p < 0.001, Chi-square test for trend). The likelihood ratio for positive CT findings in patients with a CRP level greater than 130 mg/L was 3.45 with reported specificity and sensitivity of 90.9 and 31.4 %, respectively. A low CRP level (0-5 mg/L) does not out rule positive findings on CT in the clinical setting of the acute abdomen. Increasing levels of CRP predict, with increasing likelihood, positive findings on CT.

An assessment of the feasibility and effectiveness of an e-learning module in delivering a curriculum in radiation protection to undergraduate medical students.

PURPOSE: Integrating radiation protection (RP) education in the undergraduate medical curriculum is gaining importance and is mandatory in certain jurisdictions. An e-learning module for RP was developed at the authors' medical school and was integrated into year 4 of the 5-year undergraduate medical program. The aim of this study was to investigate its impact on RP knowledge, student preferences for various teaching methods, self-assessment of RP knowledge, and perceptions of career prospects in radiology. Likert-type 5-point scale evaluations and general comments about the RP module and various methods of teaching were also obtained. METHODS: An e-learning module in RP was designed and presented to year 4 medical undergraduates. All students were required to complete premodule and postmodule questionnaires. RESULTS: Eighty-nine percent (n = 113) and 99% (n = 126) of the 127 medical students successfully completed and returned the premodule and postmodule questionnaires, respectively. After the e-learning module, students' postmodule RP knowledge had improved significantly. Analysis of postmodule RP knowledge suggested that a favorable self-assessment of knowledge of RP, perception of career prospects in radiology, and completion of the e-learning module with an increased number of sessions were factors predictive of improved RP knowledge. Students expressed a preference for didactic lectures and clinical attachment for instruction in RP over e-learning. CONCLUSIONS: The development of an e-learning module in RP is feasible and results in improved knowledge of RP among medical undergraduates. Combining e-learning and more traditional educational programs such as a clinical radiology rotation is likely to improve student experience.

Emergency CT brain: preliminary interpretation with a tablet device: image quality and diagnostic performance of the Apple iPad.

Tablet devices have recently been used in radiological image interpretation because they have a display resolution comparable to desktop LCD monitors. We identified a need to examine tablet display performance prior to their use in preliminary interpretation of radiological images. We compared the spatial and contrast resolution of a commercially available tablet display with a diagnostic grade 2 megapixel monochrome LCD using a contrast detail phantom. We also recorded reporting discrepancies, using the ACR RADPEER system, between preliminary interpretation of 100 emergency CT brain examinations on the tablet display and formal review on a diagnostic LCD. The iPad display performed inferiorly to the diagnostic monochrome display without the ability to zoom. When the software zoom function was enabled on the tablet device, comparable contrast detail phantom scores of 163 vs 165 points were achieved. No reporting discrepancies were encountered during the interpretation of 43 normal examinations and five cases of acute intracranial hemorrhage. There were seven RADPEER2 (understandable) misses when using the iPad display and 12 with the diagnostic LCD. Use of software zoom in the tablet device improved its contrast detail phantom score. The tablet allowed satisfactory identification of acute CT brain findings, but additional research will be required to examine the cause of "understandable" reporting discrepancies that occur when using tablet devices.

Bowel preparation in CT colonography: electrolyte and renal function disturbances in the frail and elderly patient.

PURPOSE: Elderly patients are at increased risk of biochemical disturbances secondary to cathartic medications. This study investigates the renal function, electrolyte and clinical disturbances associated with CT colonography (CTC) with sodium picosulphate-magnesium citrate (SPS-MC) in a subgroup of frail, elderly patients. METHODS: Patients aged over 70 years considered at risk of complication during SPS-MC administration by a physician specialised in care of the elderly were included in this retrospective study. Biochemical parameters pre- and post-CTC and the presence of co-morbidities were recorded. Imaging findings and quality of bowel preparation at CTC were graded by consensus by two radiologists. RESULTS: Of the 72 patients 56% had co-morbidities that caution the use of SPS-MC. No significant changes in serum urea, sodium, potassium or estimated glomerular filtration rate (eGFR) occurred post-CTC (p > 0.10). Serum magnesium increased by 0.11 mmol/L in 14 patients (p = 0.03) without clinical sequelae. Good overall preparation was achieved in 88% of patients, allowing confident identification of signs of colonic neoplasia in 20 patients (27%). A mild increase in serum magnesium but no other significant biochemical disturbance was observed. CONCLUSION: In our group CTC with SPS-MC was safe and effective; however, we advise an alternate preparation be considered in patients with decreased renal function due to decreased magnesium clearance.