Radiological predictive factors of transmural intestinal necrosis in acute mesenteric ischemia: systematic review and meta-analysis – European Radiology

Zeng, Y., Yang, F., Hu, X. et al. Radiological predictive factors of transmural intestinal necrosis in acute mesenteric ischemia: systematic review and meta-analysis. Eur Radiol 33, 2792–2799 (2023). https://doi.org/10.1007/s00330-022-09258-5

Acute mesenteric ischemia (AMI) occurs when there is inadequate blood supply to the intestine and may result in intestinal inflammatory injury and necrosis. A high mortality makes rapid diagnosis imperative. Clinical diagnosis can be challenging due to nonspecific patient presentation and lab values, making imaging extremely important for diagnosis. The presence of transmural intestinal necrosis (TIN) is one feature which can help distinguish between reversible early ischemia and late, nonreversible ischemia which necessitates surgery. This review and meta-analysis aims to review the current literature on the radiological predictors of TIN in patients with AMI. After exclusion criteria, 11 studies from multiple countries were selected, which included a total of 1037 patients. After meta-analysis, the authors found that bowel wall thinning, decreased or absent bowel wall enhancement, bowel dilation, pneumatosis intestinalis, porto-mesenteric venous gas, and arterial occlusive AMI versus venous occlusive AMI were risk factors. An important pitfall for imaging of AMI is interpretation of bowel dilation and wall thinning as being caused by obstruction or ileus rather than AMI. Close attention to the vessels is vital to avoiding this pitfall.

Combined ultrasonography and CT for prognosis and predicting clinical outcomes of patients with pseudomyxoma peritonei – European Radiology

Pseudomyxoma peritonei (PMP) most commonly originates from ruptured appendiceal neoplasms and is often treated with cytoreductive surgery (CRS). The surgical peritoneal cancer index (S-PCI), obtained by surgical exploration, can predict outcomes and benefits in patients undergoing CRS for PMP, however surgical exploration can be limited due to adhesions, making preoperative imaging helpful for preoperative planning. Computed tomography (CT) remains the best option for preoperative imaging, however it may underestimate the true PCI due to insufficient soft tissue contrast. Ultrasonography (US) remains under-investigated as an adjunctive imaging technique. The authors compared outcome prediction accuracy of CT alone vs. combined US/CT in addition to the predictive value of CT and US for incomplete cytoreduction. This retrospective study ultimately selected 504 patients with PMP scheduled for CRS. Tumor burden (PCI), as determined by preoperative US and CT (US-CT-PCI) vs. surgical findings was evaluated. The prognostic value of US-CT for PCI in determining the completeness of cytoreduction was also evaluated. The authors found that US + CT PCI demonstrated a high PCI accuracy under moderate tumor burden, with higher PCI accurately predicting incomplete resection. Some imaging features, such as mesenteric involvement, were found to be predictors of incomplete resection.

Han, X., Zhang, Q., Zhou, N. et al. Combined ultrasonography and CT for prognosis and predicting clinical outcomes of patients with pseudomyxoma peritonei. Eur Radiol 33, 2800–2808 (2023). https://doi.org/10.1007/s00330-022-09242-z

Making intussusception reductions easier: use of medical air in lieu of manual pump – Pediatric Radiology

Intussusception, one of the most common urgent abdominal conditions in children and infants, is currently most often treated with air reduction enema. Since the early 90’s, reduction using a handheld insufflator and pressure gauge device designed for use with one hand has been standard. Some downfalls of this method are fatigue to the operator and the frequent requirement of additional operators during lengthy reductions. A modified technique has been developed which makes use of hospital wall air to reduce these downfalls. This retrospective study aimed to compare ease of use, safety, and clinical efficacy of the wall air technique to the currently standard hand-insufflation technique and report on logistics of implementation, in addition to describing their experience with the technique. Intussusceptions of 167 patients over a several year period were reviewed and compared. A questionnaire was sent to radiologists and fluoroscopy techs who were familiar with both techniques. The authors found that between the two techniques there was no statistical difference in procedure duration or success rate. The wall air technique was found to be preferred, while being easier to use. Most that responded to the questionnaire believed the wall air technique to be faster, with a higher success rate, despite there being no significant difference. The authors conclude that hospital wall air can be used to successfully reduce intussusceptions without incurring time burden or loss of effectiveness.

Snyder, E.J., Pruthi, S. & Hernanz-Schulman, M. Making intussusception reductions easier: use of medical air in lieu of manual pump. Pediatr Radiol 53, 217–222 (2023). https://doi.org/10.1007/s00247-022-05461-0

Multiplexed sensitivity-encoding diffusion-weighted imaging (MUSE) in diffusion-weighted imaging for rectal MRI: a quantitative and qualitative analysis at multiple b-values – Abdominal Radiology

The most used diffusion weighted (DWI) magnetic resonance image (MRI) sequence is single-shot echo planar imaging (ss-EPI). These MRI sequences are essential for imaging of rectal cancer. Ss-EPI is very susceptible to main field inhomogeneities and local gradients, which can severely degrade images. Multiplexed sensitivity encoding (MUSE) is a recently developed sequence that can correct motion-induced phase errors which can occur with multi shot-EPI (ms-EPI), which is itself used to increase spatial resolution and decrease artifact with ss-EPI. Another promising new DWI sequence is field-of-view (FOV) optimized and constrained undistorted single-shot (FOCUS). This study aims to compare ss-EPI b800, FOCUS b1500, MUSE b800, and b1500 in rectal MRI for image quality, rectal contour, and lesion conspicuity, and to assess the difference in their signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC). After exclusion criteria, the imaging for 30 patients who underwent MRI on a 3T scanner were reviewed. Two radiologists, blinded to DWI sequence and clinical findings, scored the images for image quality, sharpness of the rectum, and rectal lesion conspicuity.  MUSE b800 scored significantly higher for image quality, rectal contour, and lesion conspicuity compared to ss-EPI and significantly higher for image quality and rectal contour versus all other sequences. Lesion conspicuity was superior for both MUSE b800 and MUSE b1500.

El Homsi, M., Bates, D.D.B., Mazaheri, Y. et al. Multiplexed sensitivity-encoding diffusion-weighted imaging (MUSE) in diffusion-weighted imaging for rectal MRI: a quantitative and qualitative analysis at multiple b-values. Abdom Radiol 48, 448–457 (2023). https://doi.org/10.1007/s00261-022-03710-2

Follow-up ultrasonographic findings among children treated conservatively for uncomplicated acute appendicitis – Pediatric Radiology

Acute appendicitis, generally surgically treated, is the most common surgical emergency in children, however recent research has shown conservative management with antibiotics is feasible in children with uncomplicated AA. Ultrasound (US) is a key initial modality for evaluation of children with suspected AA, but the usefulness of US for follow-up of patients treated nonoperatively for uncomplicated acute appendicitis is limited. This study aims to evaluate the outcomes of children with AA treated nonoperatively, describe the follow-up appearance of the appendix, to identify signs predictive of recurrent acute appendicitis and to assess ultrasound follow-up as a tool. After exclusion criteria, this cohort study followed 204 patients. By the end of follow-up, 29 (14.2%) of the children developed recurrent AA and 175 recovered uneventfully. In general, progressive decrease in appendiceal diameter was noted on follow-up ultrasound. Appendiceal diameter > 6 mm and intraluminal fluid or sludge were found to be increased in children who later developed recurrent AA. The study suggests that that US can be a useful tool for follow-up in children with conservatively treated AA and may help predict recurrence.

Stackievicz, R., Milner, R., Werner, M. et al. Follow-up ultrasonographic findings among children treated conservatively for uncomplicated acute appendicitis. Pediatr Radiol 53, 223–234 (2023). https://doi.org/10.1007/s00247-022-05497-2