The Peritoneum: Anatomy, Pathologic Findings, and Patterns of Disease Spread.

Disease spread in the abdomen and pelvis generally occurs in a predictable pattern in relation to anatomic landmarks and fascial planes. Anatomically, the abdominopelvic cavity is subdivided into several smaller spaces or compartments by key ligaments and fascial planes. The abdominal cavity has been traditionally divided into peritoneal, retroperitoneal, and pelvic extraperitoneal spaces.

Imaging after Pancreatic Surgery: Expected Findings and Postoperative Complications.

Pancreatic surgery is considered one of the most technically challenging surgical procedures, despite the evolution of modern techniques. Neoplasms remain the most common indication for pancreatic surgery, although inflammatory conditions may also prompt surgical evaluation. The choice of surgical procedure depends on the type and location of the pathologic finding because different parts of the pancreas have separate vascular supplies that may be shared by adjacent organs.

ACR Appropriateness Criteria® Left Lower Quadrant Pain: 2023 Update.

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.

MRI assessment of rectal cancer response to neoadjuvant therapy: a multireader study.

Objectives: A watch and wait strategy with the goal of organ preservation is an emerging treatment paradigm for rectal cancer following neoadjuvant treatment. However, the selection of appropriate patients remains a challenge. Most previous efforts to measure the accuracy of MRI in assessing rectal cancer response used a small number of radiologists and did not report variability among them.

Targeted degradation via direct 26S proteasome recruitment.

Engineered destruction of target proteins by recruitment to the cell's degradation machinery has emerged as a promising strategy in drug discovery. The majority of molecules that facilitate targeted degradation do so via a select number of ubiquitin ligases, restricting this therapeutic approach to tissue types that express the requisite ligase. Here, we describe a new strategy of targeted protein degradation through direct substrate recruitment to the 26S proteasome.

ACR Appropriateness Criteria® Right Lower Quadrant Pain: 2022 Update.

This document focuses on imaging in the adult and pregnant populations with right lower quadrant (RLQ) abdominal pain, including patients with fever and leukocytosis. Appendicitis remains the most common surgical pathology responsible for RLQ abdominal pain in the United States. Other causes of RLQ pain include right colonic diverticulitis, ureteral stone, and infectious enterocolitis.

ACR Appropriateness Criteria® Hernia.

Abdominopelvic hernias are common clinical entities composed of a wide variety of congenital, traumatic, and iatrogenic etiologies. Any weakness in the body wall may result in hernia of cavity contents with concomitant risks of morbidity and mortality. Presentations may be specific, palpable body wall mass/bulge, or vague, nonspecific pain through bowel obstruction.

Review of uterine fibroids: imaging of typical and atypical features, variants, and mimics with emphasis on workup and FIGO classification.

Uterine fibroids are the most common gynecologic neoplasm. Although non-degenerated fibroids are easily identifiable on imaging, degenerated fibroids, fibroid variants, and fibroids with unusual growth patterns can constitute a diagnostic dilemma. Identification of these abnormal morphologic features can alter the diagnosis of presumed uterine fibroids and hence change management plans.

ACR Appropriateness Criteria® Staging of Colorectal Cancer: 2021 Update.

Preoperative imaging of rectal carcinoma involves accurate assessment of the primary tumor as well as distant metastatic disease. Preoperative imaging of nonrectal colon cancer is most beneficial in identifying distant metastases, regardless of primary T or N stage. Surgical treatment remains the definitive treatment for colon cancer, while organ-sparing approach may be considered in some rectal cancer patients based on imaging obtained before and after neoadjuvant treatment.

ACR Appropriateness Criteria® Anorectal Disease.

This review summarizes the relevant literature for the selection of the initial imaging in 4 clinical scenarios in patients with suspected inflammatory disease or postoperative complication of the anorectum. These clinical scenarios include suspected perianal fistula or abscess; rectovesicular or rectovaginal fistula; proctitis or pouchitis; and suspected complication following proctectomy, coloproctectomy, or colectomy with a pouch or other anastomosis. The appropriateness of imaging modalities as they apply to each clinical scenario is rated as usually appropriate, may be appropriate, and usually not appropriate to assist the selection of the most appropriate imaging modality in the corresponding clinical scenarios of anorectal disease.

Can Hernia Sac to Abdominal Cavity Volume Ratio Predict Fascial Closure Rate for Large Ventral Hernia? Reliability of the Tanaka Score.

Background: The hernia sac to abdominal cavity volume ratio (VR) on abdominal CT was described previously as a way to predict which hernias would be less likely to achieve fascial closure. The aim of this study was to test the reliability of the previously described cutoff ratio in predicting fascial closure in a cohort of patients with large ventral hernias.

Methods: Patients who underwent elective, open incisional hernia repair of 18 cm or larger width at a single center were identified.

Activation of the IRE1 RNase through remodeling of the kinase front pocket by ATP-competitive ligands.

Inositol-Requiring Enzyme 1 (IRE1) is an essential component of the Unfolded Protein Response. IRE1 spans the endoplasmic reticulum membrane, comprising a sensory lumenal domain, and tandem kinase and endoribonuclease (RNase) cytoplasmic domains. Excess unfolded proteins in the ER lumen induce dimerization and oligomerization of IRE1, triggering kinase trans-autophosphorylation and RNase activation.

ACR Appropriateness Criteria® Crohn Disease.

Three common clinical scenarios involving use of imaging in Crohn disease are covered. These include the initial evaluation of Crohn disease when the diagnosis has not been previously established, the evaluation for anticipated exacerbation of known disease, and the evaluation of disease activity during therapy monitoring. The appropriateness of a given imaging modality for each scenario is rated as one of three categories (usually appropriate, may be appropriate, usually not appropriate) to help guide evaluation.

ACR Appropriateness Criteria® Suspected Small-Bowel Obstruction.

Small-bowel obstruction is a common cause of abdominal pain and accounts for a significant proportion of hospital admissions. Radiologic imaging plays the key role in the diagnosis and management of small-bowel obstruction as neither patient presentation, the clinical examination, nor laboratory testing are sufficiently sensitive or specific enough to diagnose or guide management. This document focuses on the imaging evaluation of the two most commonly encountered clinical scenarios related to small-bowel obstruction: the acute presentation and the more indolent, low-grade, or intermittent presentation.

Cyanopyrrolidine Inhibitors of Ubiquitin Specific Protease 7 Mediate Desulfhydration of the Active-Site Cysteine.

Ubiquitin specific protease 7 (USP7) regulates the protein stability of key cellular regulators in pathways ranging from apoptosis to neuronal development, making it a promising therapeutic target. Here we used an engineered, activated variant of the USP7 catalytic domain to perform structure-activity studies of electrophilic peptidomimetic inhibitors. Employing this USP7 variant, we found that inhibitors with a cyanopyrrolidine warhead unexpectedly promoted a β-elimination reaction of the initial covalent adducts, thereby converting the active-site cysteine residue to dehydroalanine.

Small bowel transplant: state-of-the-art vascular and nonvascular imaging.

Background: Small bowel transplant (SBT) is a surgical procedure that may be used in patients with pathology resulting in severe intestinal failure resistant to conventional forms of surgical and nonsurgical treatment. Intestinal failure is defined as the failure of enterocytes to absorb sufficient macronutrients, water, and/or electrolytes to sustain homeostasis and/or promote growth. With the advancement of surgical techniques and advancements in perioperative transplant management, SBT has become an increasingly common treatment for intestinal failure, with survival rates for SBT comparable to those for other solid organ transplants.

Endothelial intercellular cell adhesion molecule 1 contributes to cell aggregate formation in CHO cells cultured in serum-free media.

Chinese hamster ovary (CHO) cells have been adapted to grow in serum-free media and in suspension culture to facilitate manufacturing needs. Some CHO cell lines, however, tend to form cell aggregates while being cultured in suspension. This can result in reduced viability and capacity for single cell cloning (SCC) via limiting dilution, and process steps to mitigate cell aggregate formation, for example, addition of anti-cell-aggregation agents.

ACR Appropriateness Criteria® Palpable Abdominal Mass-Suspected Neoplasm.

Palpable abdominal masses may arise from the abdominal cavity or the abdominal wall. The differential diagnosis is broad for each variant ranging from benign lipomas, inflammatory processes, to malignant tumors. The imaging approach to diagnosis varies by location.

ACR Appropriateness Criteria Left Lower Quadrant Pain-Suspected Diverticulitis.

This review summarizes the relevant literature regarding imaging of suspected diverticulitis as an etiology for left lower quadrant pain, and imaging of complications of acute diverticulitis. The most common cause of left lower quadrant pain in adults is acute sigmoid or descending colonic diverticulitis. Appropriate imaging triage for patients with suspected diverticulitis should address the differential diagnostic possibilities and what information is necessary to make a definitive management decision.

Hepatic capsular retraction: An updated MR imaging review.

Hepatic capsular retraction is a morphologic descriptor that refers to invagination or focal flattening of the typical smooth contour of the liver capsule. It is an uncommon finding that, when combined with other imaging features and clinical context, can help to refine the differential diagnosis in patients with liver lesions. Although this descriptor has historically been used in reference to a small subset of benign and malignant lesions, the differential has since been expanded with the discovery of new entities causing capsular retraction as well as with novel and increased use of liver-directed treatment techniques.

Iron-Containing Abdominal Pathologies: Exploiting Magnetic Susceptibility Artifact on Dual-Echo Gradient-Echo Magnetic Resonance Imaging.

A multitude of pathologic entities involve abnormal iron deposition in the abdomen. These lesions demonstrate decreased signal on longer magnetic resonance sequences with longer echo time due to T2* effect. Dual-echo gradient-echo sequences demonstrate increased susceptibility artifact with longer echo sequences.

Diagnostic accuracy of MRI with extracellular vs. hepatobiliary contrast material for detection of residual hepatocellular carcinoma after locoregional treatment.

Purpose: To compare the diagnostic accuracy of extracellular gadolinium-based contrast-enhanced MRI (Gd-MRI) and gadoxetic acid-enhanced MRI (EOB-MRI) for the assessment of hepatocellular carcinoma (HCC) response to locoregional therapy (LRT) using explant correlation as the reference standard.

Methods: Forty-nine subjects with cirrhosis and HCC treated with LRT who underwent liver MRI using either Gd-MRI (n = 26) or EOB-MRI (n = 23) within 90 days of liver transplantation were included. Four radiologists reviewed the MR images blinded to histology to determine the size and percentage of viable residual HCC using a per-lesion explant reference standard.

Acquired Cystic Disease-associated Renal Cell Carcinoma (ACD-RCC): A Multiinstitutional Study of 40 Cases With Clinical Follow-up.

The incidence of renal cell carcinoma (RCC) is known to be higher in patients with end-stage renal disease, including those with acquired cystic kidney disease due to dialysis. Acquired cystic disease (ACD)-associated RCC was recently incorporated into the 2016 WHO Classification of Tumors of the Urinary System and Male Genital Tract as a distinct entity and is reportedly the most common RCC arising in end-stage renal disease. In this study, we sought to further describe clinicopathologic findings in a large series of ACD-RCC, emphasizing histologic features, immunophenotype, clinical outcome, and patterns of disease spread.