Crohn’s disease active inflammation assessment with iodine density from dual-energy CT enterography: comparison with endoscopy and conventional interpretation – Abdominal Radiology

Endoscopic healing is a widely accepted treatment target for Crohn’s disease (CD). Despite this, ileocolonoscopy cannot evaluate disease proximal to the terminal ileum (TI) and can miss submucosal inflammation in up to 57% of cases. Thus, cross sectional imaging, particularly CT enterography (CTE), is critical for assessing CD activity. This study aims to compare iodine density Dual energy CT enterography (DECTE) to conventional CTE and endoscopic disease activity assessment in patients with CD.  After multiple exclusion criteria 33 patients with CD who underwent DECTE and endoscopy (within 14 days of each other) were selected. A gastroenterologist, blinded to imaging findings evaluated the ileocolonoscopic images and endoscopic reports to determine the presence of endoscopically active inflammation. DECTE images were reviewed for active inflammation by two fellowship-trained body radiologists blinded to endoscopy and pathology results. Mean iodine density from DECTE had 94.4% sensitivity, 92.3% specificity, and 90.3% accuracy for the diagnosis of endoscopically active inflammation in CD patients. However, there was no statistically significant difference in sensitivity, specificity, or accuracy for the iodine density parameters compared with conventional CTE interpretation. The authors concluded that normalized iodine density is a reliable figure in defining endoscopically active CD and may be considered as a CD treatment target as a surrogate for endoscopy.

Dane, B., Kernizan, A., O’Donnell, T. et al. Crohn’s disease active inflammation assessment with iodine density from dual-energy CT enterography: comparison with endoscopy and conventional interpretation. Abdom Radiol 47, 3406–3413 (2022). https://doi.org/10.1007/s00261-022-03605-2

Accurate staging of non-metastatic colon cancer with CT: the importance of training and practice for experienced radiologists and analysis of incorrectly staged cases – Abdominal Radiology

One concern about neoadjuvant chemotherapy for colon cancer is avoiding unnecessary treatment of low-risk patients through accurate radiologic staging. The role of pre-treatment CT for colon cancer includes detection of distant metastases and locoregional staging. Due to multiple factors, this locoregional staging is challenging, with a steep learning curve. This study investigated whether staging and radiologist confidence can be improved by repetition and by receiving training and feedback, with an emphasis on overstaging. 45 patients who underwent presurgical CT and colon resection through the MATCH study were selected. Five abdominal radiologists interpreted imaging for T staging (0-4), N staging and reading time.  They first read 5 cases as they normally would during practice, to establish baseline accuracy, after which they had a 45 minute lecture on CT staging for colon cancer. The radiologists then interpreted 40 cases over 4 weeks. After interpretation, some of the radiologists received feedback with comparison of their performance to histopathologic data, while some of the radiologists received no feedback. The ability to distinguish T1-2 vs. T3-4 disease improved significantly with increasing number of reviewed cases. In this study, incorrect staging was more frequently caused by under rather than over-staging. No improvement in detection of lymph nodes was seen in any of the radiologist groups. Interestingly, longer reading times and lower confidence in staging were seen in the group receiving feedback, possibly due to more detailed assessment and raised awareness of imaging limitations. This study ultimately suggests that experienced radiologists can improve diagnostic performance in locoregional staging of colon cancer on CT after training and repetition.

van de Weerd, S., Hong, E., van den Berg, I. et al. Accurate staging of non-metastatic colon cancer with CT: the importance of training and practice for experienced radiologists and analysis of incorrectly staged cases. Abdom Radiol 47, 3375–3385 (2022). https://doi.org/10.1007/s00261-022-03573-7

Comparison of contrast-enhanced fat-suppressed T1-3D-VIBE and T1-TSE MRI in evaluating anal fistula – abdominal radiology

Anal fistulas (AF) are a relatively common ano-rectal pathology, which can be excellently demonstrated on magnetic resonance imaging (MRI). It has been proposed that 3D MRI acquisitions may be an alternative to 2D acquisitions and could be optimally combined with other sequences to characterize AF. This study investigated the effectiveness of T1-weighted volumetric interpolated breath-hold examination (T1-VIBE) and T1-weighted turbo spin echo (T1-TSE) sequences in assessing AF prior to surgery. This prospective study selected 102 patients having been diagnosed with AF, after multiple exclusion criteria. These patients underwent MRI examination which included both T1-VIBE and T1-TSE sequences, after which the images were reviewed by two independent radiologists. Various MR imaging characteristics of the fistulas were described for preoperative use. Surgery was then performed by two anal-rectal surgeons, with surgery considered the gold standard for evaluating AF. The authors found that the T1-VIBE sequence was superior to T1-TSE in accurately diagnosing complex fistula, in addition to having the advantages of thinner slice thickness, shorter acquisition times and higher image quality. The implication being that T1-VIBE is more valuable for preoperative planning for AF.

Zhao, J., Lu, F., Wang, Q. et al. Comparison of contrast-enhanced fat-suppressed T1-3D-VIBE and T1-TSE MRI in evaluating anal fistula. Abdom Radiol 47, 3688–3697 (2022). https://doi.org/10.1007/s00261-022-03661-8

Positive Versus Neutral Oral Contrast Material for Detection of Malignant Deposits in Intraabdominal Nonsolid Organs on CT – American Journal of Radiology

The detection of tumor deposits in nonsolid organs is critical for proper staging, treatment and management of malignancy. This study compared the use of neutral vs positive oral contrast material for detection of malignant deposits in nonsolid organs within the abdominal cavity on CT. After a selection process this retrospective study included 265 patients who underwent an abdominopelvic CT exam which showed no suggestion of malignant deposits (study exam) and a subsequent CT exam performed within 6 months that did show at least one definite malignant deposit (follow up exam).
Of these 265 patients, 100 received positive oral contrast and 165 received neutral oral contrast. Initially, one radiologist retrospectively reviewed all imaging to identify study exams which had malignant deposits and assigned the deposit to one of seven anatomic compartments of the intraabdominal cavity. This radiologist also graded the adequacy of bowel filling on a scale of 1 (very poor) to 5 (very good). Eighteen months later, two radiologists reviewed the study exams (without reviewing the follow up exam) and recorded the presence or absence of malignant deposits for each of the seven compartments. The negative predictive value for malignant deposits was 65.8% for positive contrast with adequate bowel filling, 45.2% for positive contrast with inadequate bowel filling and 35.2% for neutral oral contrast. Thus, positive contrast was superior to neutral contrast in detecting malignant deposits on nonsolid organs. This detection was further improved with adequate filling of the bowel.

An C, Obmann MM, Sun Y, et al. Positive Versus Neutral Oral Contrast Material for Detection of Malignant Deposits in Intraabdominal Nonsolid Organs on CT. American Journal of Roentgenology. 2022;219(2):233-243. doi:10.2214/ajr.21.27319

Preoperative prediction of inadvertent enterotomy during adhesive small bowel obstruction surgery using combination of CT features – European radiology

Small bowel obstruction is a common pathological entity that is most often caused by single adhesive bands or matted dense adhesions. Inadvertent enterotomy (IE) is a complication of surgery for adhesive small bowel obstruction (ASBO), which increases patient morbidity (lengthened hospital stay, higher complication rates) and mortality.  This study aims to identify CT imaging features that may be associated with occurrence of IE after ASBO surgery. After exclusion criteria, 169 patients with surgically treated ASBO who had CT scans available were selected. Various characteristics of the patients imaging, and surgical reports were analyzed by abdominal radiologists and digestive surgeons, respectively. Patients who had a higher number of prior laparotomies had a higher incidence of IE, and IE was more frequent with patients with matted dense adhesions vs single adhesive bands. The authors found that two CT features were predictive of IE: diffuse intestinal adhesions (long adhesions of bowel loops to each other) and acute transition point angulation. CT features which were found to suggest protection from IE were the fat notch sign (oval fat density at the transitional zone corresponding to the extrinsic extraluminal band compression) and mesenteric haziness. Using these CT imaging features the authors developed a scoring system to stratify the risk of IE.

Zein, L., Calame, P., Chausset, C. et al. Preoperative prediction of inadvertent enterotomy during adhesive small bowel obstruction surgery using combination of CT features. Eur Radiol 32, 6646–6657 (2022). https://doi.org/10.1007/s00330-022-08951-9