Faculty Bibliography

INTRODUCTION/BACKGROUND:The purpose of this study was to evaluate the role of body mass index (BMI) in predicting postoperative complications following myocutaneous free flap transfer. In addition, we sought to identify certain body composition variables that may be used to stratify patients into low- versus high-risk for gracilis myocutaneous free flap with skin paddle failure. METHODS:Using the National Surgical Quality Improvement Program database, we collected data for all patients who underwent myocutaneous free flap transfer from 2015 to 2021. Demographic data, medical history, surgical characteristics, and postoperative outcomes, including complications, reoperations, and readmissions, were collected. Body mass index was correlated with outcome measures to determine its role in predicting myocutaneous free flap reliability. Subsequently, we retrospectively obtained measurements of perigracilis anatomy in patients who underwent computed tomography angiography bilateral lower extremity scans with intravenous contrast at our institution. We compared body composition data with mathematical equations calculating the potential area along the skin of the thigh within which the gracilis perforator may be found. RESULTS:Across the United States, 1549 patients underwent myocutaneous free flap transfer over the 7-year study period. Being in obesity class III (BMI ≥40 kg/m2) was associated with a 4-times greater risk of flap complications necessitating a return to the operating room compared with being within the normal BMI range. In our computed tomography angiography analysis, average perigracilis adipose thickness was 18.3 ± 8.0 mm. Adipose thickness had a strong, positive exponential relationship with the area of skin within which the perforator may be found. CONCLUSIONS:In our study, higher BMI was associated with decreased myocutaneous free flap reliability. Specifically, inner thigh adipose thickness can be used to estimate the area along the skin within which the gracilis perforator may be found. This variable, along with BMI, can be used to identify patients who are considered high-risk for flap failure and who may benefit from additional postoperative monitoring, such as the use of a color flow Doppler probe and more frequent and prolonged skin paddle monitoring.

Although extraintestinal manifestations of inflammatory bowel disease (IBD) are common, pulmonary IBD is extremely rare. Owing to its nonspecific clinical, radiologic, and pathologic features, pulmonary IBD is difficult to diagnose and may mimic more concerning disease processes. We present a rare case of a patient with known Crohn's disease whose initial presentation was highly suspicious for malignancy before further investigation revealed pulmonary IBD.

PURPOSE/OBJECTIVE:To determine optimal iodine density thresholds for active inflammation in CD patients with PCCT enterography and determine if iodine density can be used to stratify CD activity severity. METHODS:A retrospective PACS search identified patients with CD imaged with PCCT enterography from 4/11/2022 to 10/30/2022 and with clinical notes, endoscopic/surgical pathology and available source PCCT data for iodine density analysis. Two abdominal radiologists with expertise in CD each drew two region of interest measurements within the visibly most affected region of terminal or neoterminal ileum wall on commercially available system (SyngoVia). Radiologists were blinded to clinical information and pathologic findings. Disease activity and severity were recorded from the pathology report. Harvey-Bradshaw Index, medications, and laboratory values were recorded. Receiver operating characteristic (ROC) curves were utilized to determine the optimum iodine density threshold for active inflammation and mild versus moderate-to-severe inflammation. Intra- and inter-reader agreement was assessed by intra-class correlation coefficient (ICC). RESULTS:23 CD patients (15 females; mean [SD] age: 52 [17] years) imaged with PCCT enterography were included. 15/23 had active inflammation: 9/15 mild, 4/15 moderate, and 2/15 severe active inflammation. The optimal iodine density threshold for active inflammation was 2.7 mg/mL, with 97% sensitivity, 100% specificity, and 98% accuracy (AUC = 1.00). The optimal iodine density threshold for distinguishing mild from moderate-to-severe inflammation was 3.4 mg/mL, with 83% sensitivity, 89% specificity, and 87% accuracy (AUC = 0.85). Intra-reader reliability (R1/R2) ICC was 0.81/0.86. Inter-reader reliability ICC was 0.94. CONCLUSION/CONCLUSIONS:Iodine density from PCCT enterography can distinguish mild from moderate-to-severe active inflammation.

Compared to conventional single-energy CT (SECT), dual-energy CT (DECT) provides additional information to better characterize imaged tissues. Approaches to DECT acquisition vary by vendor and include source-based and detector-based systems, each with its own advantages and disadvantages. Despite the different approaches to DECT acquisition, the most utilized DECT images include routine SECT equivalent, virtual monoenergetic, material density (eg, iodine map), and virtual non-contrast images. These images are generated either through reconstructions in the projection or image domains. Designing and implementing an optimal DECT workflow into routine clinical practice depends on radiologist and technologist input with special considerations including appropriate patient and protocol selection and workflow automation. In addition to better tissue characterization, DECT provides numerous advantages over SECT such as the characterization of incidental findings and dose reduction in radiation and iodinated contrast.

The differential diagnosis for left lower quadrant pain is wide and conditions range from the benign and self-limited to life-threatening surgical emergencies. Along with patient history, physical examination, and laboratory tests, imaging is often critical to limit the differential diagnosis and identify life-threatening abnormalities. This document will discuss the guidelines for the appropriate use of imaging in the initial workup for patients who present with left lower quadrant pain, patients with suspected diverticulitis, and patients with suspected complications from diverticulitis. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Ileal pouch surgery is the surgical gold standard treatment for patients with ulcerative colitis (UC) and familial adenomatous polyposis (FAP). However, ileal pouch surgery is a technically challenging procedure and is associated with high morbidity. Clinical presentations of pouch complications are often nonspecific but imaging can identify many of these complications and is essential in clinical management. This paper will focus on magnetic resonance imaging (MRI) of the ileal pouch, including recommended MRI protocol and approach to imaging interpretation with an emphasis on those ileal pouch complications particularly well evaluated with MRI.

PURPOSE/OBJECTIVE:Given that ileal pouch-anal anastomosis (IPAA) surgery is a technically challenging and high-morbidity procedure, there are numerous pertinent imaging findings that need to be clearly and efficiently communicated to the IBD surgeons for essential patient management and surgical planning. Structured reporting has been increasingly used over the past decade throughout various radiology subspecialties to improve reporting clarity and completeness. We compare structured versus non-structured reporting of pelvic MRI for ileal pouch to evaluate for clarity and effectiveness. METHODS:164 consecutive pelvic MRI's for ileal pouch evaluation, excluding subsequent exams for the same patient, acquired between 1/1/2019 and 7/31/2021 at one institution were included, before and after implementation (11/15/2020) of a structured reporting template, which was created with institutional IBD surgeons. Reports were assessed for the presence of 18 key features required for complete ileal pouch assessment: anastomosis (IPAA, tip of J, pouch body), cuff (length, cuffitis), pouch body (size, pouchitis, stricture), pouch inlet/pre-pouch ileum (stricture, inflammation, sharp angulation), pouch outlet (stricture), peripouch mesentery (position, mesentery twist), pelvic abscess, peri-anal fistula, pelvic lymph nodes, and skeletal abnormalities. Subgroup analysis was performed based on reader experience and divided into three categories: experienced (n = 2), other intra-institutional (n = 20), or affiliate site (n = 6). RESULTS:57 (35%) structured and 107 (65%) non-structured pelvic MRI reports were reviewed. Structured reports contained 16.6 [SD:4.0] key features whereas non-structured reports contained 6.3 [SD:2.5] key features (p < .001). The largest improvement following template implementation was for reporting sharp angulation of the pouch inlet (91.2% vs. 0.9%, p < .001), tip of J suture line and pouch body anastomosis (both improved to 91.2% from 3.7%). Structured versus non-structured reports contained mean 17.7 versus 9.1 key features for experienced readers, 17.0 versus 5.9 for other intra-institutional readers, and 8.7 versus 5.3 for affiliate site readers. CONCLUSION/CONCLUSIONS:Structured reporting of pelvic MRI guides a systematic search pattern and comprehensive evaluation of ileal pouches, and therefore facilitates surgical planning and clinical management. This standardized reporting template can serve as baseline at other institutions for adaptation based on specific radiology and surgery preferences, fostering a collaborative environment between radiology and surgery, and ultimately improving patient care.

This manuscript is part of the ileal pouch symposium and will describe the water-soluble contrast enema, CT, and small bowel series. MRI and other imaging modalities are discussed elsewhere in the symposium. Water-soluble contrast enema and CT are excellent for the evaluation of the ileal pouch. Contrast enema and CT with anal contrast administration can allow for anastomotic integrity and pouch assessment. Pre-pouch ileum, extra-intestinal manifestations, and acute symptomatology are best assessed with CT. The contrast small bowel examination is of limited utility in pouch patients and should not be performed. Indications, imaging technique, and anatomic pouch assessment with water-soluble contrast enema, CT, and contrast small bowel examination will be reviewed here.

The sections of this special issue on the ileal pouch demonstrate that in the nearly 45 years since the ileal pouch has been utilized to treat patients with colitis and familial adenomatous polyposis, a substantial number of patients experience both short- and long-term morbidity and that imaging plays an important role in their management. Further, referral centers are encountering an increasing number of patients with pouch and peri-pouch complications and dysfunction. Many of these patients have had their pouches for years, and many have experienced a reduced quality of life as a result of their symptoms.As we look to the future, what are the specific questions that arise from this compilation of experience from institutions that see large numbers of patients with an ileal pouch? In what areas are we deficient? In what areas are we using the wrong methods? What should we be doing differently?

OBJECTIVE:To analyze the findings of proctitis in patients with laboratory-confirmed Mpox and correlate the patient clinical presentation and laboratory findings. METHODS:21 patients with PCR-positive Mpox who obtained abdominopelvic CT were retrospectively identified by electronic medical record search. Three radiologists independently evaluated CT images, measuring rectal wall thickness (cm), degree of perirectal fat stranding on a 5-point Likert scale, and size of perirectal lymph nodes (cm, short axis). Mann-Whitney U-test (Wilcoxon rank sum test) was used to assess the association of rectal wall thickness and perirectal fat standing between patients with rectal symptoms and patients without rectal symptoms. RESULTS:20 of 21 patients presented with perirectal fat stranding, with mean Likert score of 3.0 ± 1.4, indicating moderate perirectal stranding. Mean transverse rectal wall thickness was 1.1 ± 0.5 cm (range 0.3-2.3 cm); it was thicker among patients with HIV (1.2 cm vs 0.7 cm; p = .019). Mean perirectal fat stranding was greater among patients presenting with HIV, and with rectal symptoms, though not significantly so. 17/21 (81%) patients had abnormal mesorectal lymph nodes by at least two of three readers, with mean short-axis measurement 1.0 ± 0.3 cm (range 0.5-1.6 cm). Multiple linear regression showed no significant correlation between rectal thickness and laboratory values or HIV status. CONCLUSION/CONCLUSIONS:Nearly all patients with Mpox who presented with additional symptoms warranting a CT demonstrated proctitis. Degree of proctitis varied greatly within the cohort, with greatest thickening among patients with HIV. Physicians should have a high suspicion for proctitis in patients with suspected Mpox.