What’s New in Gastrointestinal Imaging? – May 2022

4 months ago

ACORE GI- Dane Eskildsen

Low-dose Abdominal CT for evaluating suspected appendicitis in adolescents and young adults: review of evidence – Korean Journal of Radiology

Concerns about carcinogenic risk have prompted attempts to reduce CT radiation dose for diagnosis of appendicitis. One option to mitigate this risk is low-dose appendiceal CT (LDCT), although adoption has been slow. This review article aims to assess the evidence for reducing CT dose for diagnosis of appendicitis in young adults and adolescents. The article first discusses the current utilization of CT for appendicitis, CT radiation dose and the carcinogenic risks of CT radiation. The carcinogenic risks of CT radiation are of particular concern for adolescent and pediatric populations. The authors then discuss the diagnostic effectiveness of LDCT vs conventional-dose CT (CDCT). Specifically, they examined clinical outcomes and diagnostic performance of LDCT vs CDCT throughout the literature, in addition to trials comparing the use of LDCT vs CDCT for complicated vs uncomplicated appendicitis. Studies regarding the use of LDCT for ruling out alternative diagnoses to appendicitis were also discussed. The authors concluded that there is compelling evidence that LDCT is comparable to CDCT for diagnosis of appendicitis in adolescents and young adults.

Park JH, Salminen P, Tannaphai P, Lee KH.   Low-Dose Abdominal CT for Evaluating Suspected Appendicitis in Adolescents and Young Adults: Review of Evidence.   Korean J Radiol. 2022 May;23(5):517-528.   https://doi.org/10.3348/kjr.2021.0596


Predictors of transmural intestinal necrosis in patients presenting with acute mesenteric ischemia on computed tomography – Abdominal Radiology

Acute mesenteric ischemia (AMI) is a potentially fatal condition that occurs when the bowel receives insufficient blood flow, which may lead to irreversible intestinal necrosis if untreated. AMI is divided into occlusive and nonocclusive etiologies. AMI is potentially reversible if early intervention is performed. Physical findings and laboratory workup are not sensitive and specific enough for diagnosis of AMI, thus, early imaging is essential for accurate diagnosis. This retrospective case-control study evaluated 48 cases of AMI (of which, 26 had pathologically confirmed transmural necrosis) to identify significant imaging characteristics that may predict bowel necrosis. The authors found the most significant predictor of transmural necrosis in occlusive causes to be vascular occlusion >70%. Pneumatosis intestinalis was also found to be a statistically significant predictor of transmural necrosis. The presence or absence of ostial stenosis, number of vessels involved, and length of occlusion were not found to predict necrosis. Additionally, other factors such ascites or fat stranding were not significant predictors.

Atre, I.D., Eurboonyanun, K., O’Shea, A. et al. Predictors of transmural intestinal necrosis in patients presenting with acute mesenteric ischemia on computed tomography. Abdom Radiol 47, 1636–1643 (2022). https://doi.org/10.1007/s00261-020-02558-8



CT Enterography Using Four Different Endoluminal Contrast Agents: A Comparative Study– Journal of Gastrointestinal and Abdominal Radiology

CT enterography (CTE) is useful for diagnosis of small bowel pathology. In CTE, oral and IV contrast are given to the patient who is then imaged at specific time intervals. Multiple oral contrast agents can be used, classified as neutral (similar in attenuation to water) or positive (attenuation higher than enhancing structures). This study attempts to determine the ideal endoluminal contrast agents, among water, polyethylene glycol (PEG), mannitol (neutral agents) and iohexol (positive agent). 120 patients had CTE performed with 30 patients each receiving one of the tested oral contrast agents. Quantitative and qualitative assessment of small bowel distention, bowel morphology (I.e. wall enhancement, luminal contents, stratification) and overall imaging quality were evaluated. Patient tolerance to the contrast materials was also evaluated using a questionnaire. PEG was found to provide the best CTE images based on each of the previously mentioned criteria, except for patient tolerance. From this data the authors determined that neutral contrast agents were superior to positive agents and that PEG is the most suitable agent to carry out CTE.

Singla, D., Chandak, S., et al CT Enterography Using Four Different Endoluminal Contrast Agents: A Comparative Study J of Gast and Abd Radiol, 2022-01, Vol.5 (1), p.016-022


Algorithmic Approach to the Splenic Lesion Based on Radiologic-Pathologic Correlation – Radiographics


Splenic masses are uncommon and pose a diagnostic challenge to radiologists. Splenic lesions are also often found incidentally, making imaging diagnosis of these lesions very important. While most splenic masses are benign, differentiating benign from malignant splenic masses is crucial. The authors of this article propose an algorithmic approach to splenic lesions based on their number and consistency. Radiologic-Pathologic correlation for various pathologic and radiologic features of splenic masses is emphasized. Following the algorithm as proposed by the authors, splenic masses are first divided into cystic vs solid. After mass consistency is established, the differential is further divided into solitary vs. Multiples masses. The radiologic and pathologic features of various splenic masses which fall into each of these categories are described. The subdivision of solitary solid splenic mass is further divided into vascular vs nonvascular entities. The authors posit that this stepwise approach may aid in the diagnosis of incidental splenic lesions.

Kim, N., Auerbach, A. and Manning, M., 2022. Algorithmic Approach to the Splenic Lesion Based on Radiologic-Pathologic Correlation. RadioGraphics, 42(3), pp.683-701.

Colorectal Cancer: Performance and Evaluation for CT Colonography Screening— A Multicenter Cluster-randomized Controlled Trial – Radiology (RSNA)

CT colonography (CTC) is used as a screening for colorectal cancer (CRC) and premalignant polyps when colonoscopy is not possible. In the UK, where this trial took place, most radiologists are not required to undergo performance accreditation for CTC. The authors aimed to determine if a 1-day individualized training in CTC improved diagnostic sensitivity of experienced radiologists. Clusters from 72 hospitals within the national health system (NHS) participated in the trial, with 3 hospitals not meeting inclusion criteria. These included radiologists of varying training levels. 38 clusters (59 radiologists, some of whom were lost to follow-up) received no individualized 1-day CTC training while 31 clusters (80 radiologists, some of whom were lost to follow-up) did receive training. Both the control and intervention groups interpreted unique CTC exams: 10 at baseline then at 1 month, 6 month and 12-month intervals, respectively. CTC exams were chosen to represent the spectrum of colorectal lesions that may be seen in practice. The authors found that radiologists who received the 1-day CTC training had greater diagnostic sensitivity for colorectal lesions greater than 0.6 cm than those that had not had the training. They also found that this benefit persisted after 6 and 12 months. For experienced radiologists in this trial, a 16.7% increase in detection of clinically relevant colorectal lesions was observed.

Obaro AE, Plumb AA, Halligan S, et al. Colorectal Cancer: Performance and Evaluation for CT Colonography Screening—A Multicenter Cluster-randomized Controlled Trial. Radiology 2022;303(2):361–370.


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