Assessment of Amniotic Fluid Volume in Pregnancy.

Amniotic fluid (AF) is an integral part of the fetal environment and is essential for fetal growth and development. Pathways of AF recirculation include the fetal lungs, swallowing, absorption through the fetal gastrointestinal tract, excretion through fetal urine production, and movement. In addition to being a marker for fetal health, adequate AF is necessary for fetal lung development, growth, and movement. The role of diagnostic imaging is to provide a detailed fetal survey, placental evaluation, and clinical correlation with maternal conditions to help identify causes of AF abnormalities and thereby enable specific therapy. Oligohydramnios prompts evaluation for fetal growth restriction as well as genitourinary issues, including renal agenesis, multicystic dysplastic kidneys, ureteropelvic junction obstruction, and bladder outlet obstruction. Premature preterm rupture of membranes should also be clinically excluded as a cause of oligohydramnios. Clinical trials evaluating amnioinfusion are underway as a potential intervention for renal causes of oligohydramnios. Most cases of polyhydramnios are idiopathic, with maternal diabetes being a common cause. Polyhydramnios prompts evaluation for fetal gastrointestinal obstruction and oropharyngeal or thoracic masses, as well as neurologic or musculoskeletal anomalies. Amnioreduction is performed only for maternal indications such as symptomatic polyhydramnios causing maternal respiratory distress. Polyhydramnios with fetal growth restriction is paradoxical and can occur with maternal diabetes and hypertension. When these maternal conditions are absent, this raises concern for aneuploidy. The authors describe the pathways of AF production and circulation, US and MRI assessment of AF, disease-specific disruption of AF pathways, and an algorithmic approach to AF abnormalities. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Positive Versus Neutral Oral Contrast Material for Detection of Malignant Deposits in Intraabdominal Nonsolid Organs on CT.

BACKGROUND. Data are limited regarding utility of positive oral contrast material for peritoneal tumor detection on CT. OBJECTIVE. The purpose of this article is to compare positive versus neutral oral contrast material for detection of malignant deposits in nonsolid intraabdominal organs on CT. METHODS. This retrospective study included 265 patients (133 men, 132 women; median age, 61 years) who underwent an abdominopelvic CT examination in which the report did not suggest presence of malignant deposits and a subsequent CT examination within 6 months in which the report indicated at least one unequivocal malignant deposit. Examinations used positive (iohexol; n = 100) or neutral (water; n = 165) oral agents. A radiologist reviewed images to assess whether the deposits were visible (despite clinical reports indicating no deposits) on unblinded comparison with the follow-up examinations; identified deposits were assigned to one of seven intraabdominal compartments. The radiologist also assessed adequacy of bowel filling with oral contrast material. Two additional radiologists independently reviewed examinations in blinded fashion for malignant deposits. NPV was assessed of clinical CT reports and blinded retrospective readings for detection of malignant deposits visible on unblinded comparison with follow-up examinations. RESULTS. Unblinded review identified malignant deposits in 58.1% (154/265) of examinations. In per-patient analysis of clinical reports, NPV for malignant deposits was higher for examinations with adequate bowel filling with positive oral contrast material (65.8% [25/38]) than for examinations with inadequate bowel filling with positive oral contrast material (45.2% [28/62], p = .07) or with neutral oral contrast material regardless of bowel filling adequacy (35.2% [58/165], p = .002). In per-compartment analysis of blinded interpretations, NPV was higher for examinations with adequate and inadequate bowel filling with positive oral contrast material than for examinations with neutral oral contrast regardless of bowel filling adequacy (reader 1: 94.7% [234/247] and 92.5% [382/413] vs 88.3% [947/1072], both p = .045; reader 2: 93.1% [228/245] and 91.6% [361/394] vs 85.9% [939/1093], both p = .01). CONCLUSION. CT has suboptimal NPV for malignant deposits in intraabdominal nonsolid organs. Compared with neutral material, positive oral contrast material improves detection, particularly with adequate bowel filling. CLINICAL IMPACT. Optimization of bowel preparation for oncologic CT may help avoid potentially severe clinical consequences of missed malignant deposits.

Sequelae of Eating Disorders at Imaging.

Although eating disorders are common, they tend to be underdiagnosed and undertreated because social stigma tends to make patients less likely to seek medical attention and less compliant with medical treatment. Diagnosis is crucial because these disorders can affect any organ system and are associated with the highest mortality rate of any psychiatric disorder. Because of this, imaging findings, when recognized, can be vital to the diagnosis and management of eating disorders and their related complications. The authors familiarize the radiologist with the pathophysiology and sequelae of eating disorders and provide an overview of the related imaging findings. Some imaging findings associated with eating disorders are nonspecific, and others are subtle. The presence of these findings should alert the radiologist to correlate them with the patient's medical history and laboratory results and the clinical team's findings at the physical examination. The combination of these findings may suggest a diagnosis that might otherwise be missed. Topics addressed include (a) the pathophysiology of eating disorders, (b) the clinical presentation of patients with eating disorders and their medical complications and sequelae, (c) the imaging features associated with common and uncommon sequelae of eating disorders, (d) an overview of management and treatment of eating disorders, and (e) conditions that can mimic eating disorders (eg, substance abuse, medically induced eating disorders, and malnourishment in patients with cancer). Online supplemental material is available for this article. ©RSNA, 2022.

Diagnosis of acute mesenteric ischemia assisted by dual-energy CT: a case report.

In this case report, dual-energy CT was critical in the diagnosis of acute mesenteric ischemia by differentiating normal contrast-enhanced bowel and hemorrhagic necrosis. Iodine map showed a segment of small bowel with minimal contrast enhancement, and virtual non-contrast imaging revealed hyperattenuating bowel. This finding changed management for the patient and prevented complications from impending bowel perforation. Histopathological analysis confirmed hemorrhagic necrosis of the bowel segment. In cases of suspected bowel ischemia, dual-energy CT can distinguish bowel wall hemorrhage from contrast enhancement and allow for accurate diagnosis.

Amyloidosis: Multisystem Spectrum of Disease with Pathologic Correlation.

Amyloidosis is a group of conditions defined by extracellular deposition of insoluble proteins that can lead to multiorgan dysfunction and failure. The systemic form of the disease is often associated with a plasma cell dyscrasia but may also occur in the setting of chronic inflammation, long-term dialysis, malignancy, or multiple hereditary conditions. Localized forms of the disease most often involve the skin, tracheobronchial tree, and urinary tract and typically require tissue sampling for diagnosis, as they may mimic many conditions including malignancy at imaging alone. Advancements in MRI and nuclear medicine have provided greater specificity for the diagnosis of amyloidosis involving the central nervous system and heart, potentially obviating the need for biopsy of the affected organ in certain circumstances. Specifically, a combination of characteristic findings at noninvasive cardiac MRI and skeletal scintigraphy in patients without an underlying plasma cell dyscrasia is diagnostic for cardiac transthyretin amyloidosis. Histologically, the presence of amyloid is denoted by staining with Congo red and a characteristic apple green birefringence under polarized light microscopy. The imaging features of amyloid vary across each organ system but share some common patterns, such as soft-tissue infiltration and calcification, that may suggest the diagnosis in the appropriate clinical context. The availability of novel therapeutics that target amyloid protein fibrils such as transthyretin highlights the importance of early diagnosis. Online supplemental material is available for this article. ©RSNA, 2021.

Müllerian Duct Anomalies: Role in Fertility and Pregnancy.

Müllerian duct anomalies (MDAs) have important implications for the reproductive health of female patients. In patients with both infertility and recurrent pregnancy loss, the incidence of MDAs is as high as 25%. Congenital uterine anomalies are often only part of a complex set of congenital anomalies involving the cervix, vagina, and urinary tract. Multiple classification systems for MDAs exist, each with different criteria that vary most for the diagnosis of septate uterus. Recognizing the features that guide clinical management is essential for interpretation. Identification of an MDA should prompt evaluation for associated urinary tract anomalies. In patients with infertility who seek to use assisted reproductive technologies such as intrauterine insemination, recognition of MDAs may have an affect on reproductive success, particularly in patients who have an incomplete and clinically occult septum that divides the cervix. Two-dimensional US is the first-line modality for evaluating the uterus and adnexa. Three-dimensional (3D) US or MRI may help to visualize the external uterine fundal contour and internal indentation of the endometrial cavity, which are two morphologic characteristics that are keys to the diagnosis of congenital uterine anomalies. Hysterosalpingo contrast-enhanced US may be performed in conjunction with 3D US to evaluate uterine morphologic characteristics, the endometrial cavity, and tubal patency in a single examination. MRI helps to characterize rudimentary uteri in patients with müllerian hypoplasia and allows assessment for ectopic ureters, abnormally positioned ovaries, or associated deep infiltrative endometriosis. Online supplemental material is available for this article. ©RSNA, 2021.

The Flipped Ovary Sign in Ovarian Torsion.

The diagnosis of ovarian torsion is challenging and relies mostly on morphologic findings. Occasionally, women or children with acute pelvic pain who have undergone an initial ultrasound (US) evaluation with results interpreted as negative for ovarian torsion will return with recurrent or increasing pain, prompting an US reevaluation. The flipped ovary sign refers to a demonstrable change in the orientation of the ovary on follow-up US examinations, recognized by changing positions of ovarian landmarks established by follicles, cysts, or masses. This sign is valuable for identifying ovarian torsion in these patients, even in the absence of classic morphologic or Doppler features of ovarian torsion.

Imaging of Renal Transplant Complications throughout the Life of the Allograft: Comprehensive Multimodality Review.

The kidney is the most commonly transplanted solid organ. Advances in surgical techniques, immunosuppression regimens, surveillance imaging, and histopathologic diagnosis of rejection have allowed prolonged graft survival times. However, the demand for kidneys continues to outgrow the available supply, and there are efforts to increase use of donor kidneys with moderate- or high-risk profiles. This highlights the importance of evaluating the renal transplant patient in the context of both donor and recipient risk factors. Radiologists play an integral role within the multidisciplinary team in care of the transplant patient at every stage of the transplant process. In the immediate postoperative period, duplex US is the modality of choice for evaluating the renal allograft. It is useful for establishing a baseline examination for comparison at future surveillance imaging. In the setting of allograft dysfunction, advanced imaging techniques including MRI or contrast-enhanced US may be useful for providing a more specific diagnosis and excluding nonrejection causes of renal dysfunction. When a pathologic diagnosis is deemed necessary to guide therapy, US-guided biopsy is a relatively low-risk, safe procedure. The range of complications of renal transplantation can be organized temporally in relation to the time since surgery and/or according to disease categories, including immunologic (rejection), surgical or iatrogenic, vascular, urinary, infectious, and neoplastic complications. The unique heterotopic location of the renal allograft in the iliac fossa predisposes it to a specific set of complications. As imaging features of infection or malignancy may be nonspecific, awareness of the patient's risk profile and time since transplantation can be used to assign the probability of a certain diagnosis and thus guide more specific diagnostic workup. It is critical to understand variations in vascular anatomy, surgical technique, and independent donor and recipient risk factors to make an accurate diagnosis and initiate appropriate treatment.©RSNA, 2019.

CT Findings of Acute Small-Bowel Entities.

Although a broad spectrum of entities can induce acute pathologic changes in the small bowel, there are relatively few imaging features that are characteristic of a specific diagnosis on the basis of CT findings. Specific clinical information, including time course and onset of disease, patient risk factors, and any recent pharmacologic or radiation therapy, is often instrumental in refining the differential diagnosis. A wide spectrum of disorders is reviewed in this article; however, given the breadth of disorders associated with the small bowel, neoplastic and infectious conditions affecting the small bowel that can manifest acutely are not specifically discussed. Vascular diseases that can affect the small bowel regionally or diffusely, including thromboembolic and hypoperfusion phenomena, as well as a spectrum of vasculitides, are reviewed. Iatrogenic causes of small bowel disorders are discussed, including angiotensin-converting enzyme inhibitor-induced angioedema, and chemotherapy- and radiation therapy-associated patterns of disease. Autoimmune and hereditary conditions that can affect the small bowel, including systemic lupus erythematosus and genetic C1 esterase inhibitor deficiency, respectively, are reviewed. ©RSNA, 2018.

Abdominal CT findings characteristic of castleman disease: multi-center review of 76 adult cases with abdominopelvic nodal involvement.

OBJECTIVE: Characterize the CT findings of abdominopelvic Castleman disease, including a new observation involving the perinodal fat. METHODS: Multi-center search at 5 institutions yielded 76 adults (mean age, 42.1 ± 14.3 years; 38 women/38 men) meeting inclusion criteria of histopathologically-proven Castleman disease with nodal involvement at abdominopelvic CT. Retrospective review of the dominant nodal mass was assessed for size, attenuation, and presence of calcification, and for prominence and soft-tissue infiltration of the perinodal fat. Hypervascular nodal enhancement was based on both subjective and objective comparison with aortic blood pool attenuation. RESULTS: Abdominal involvement was unicentric in 48.7% (37/76) and multicentric in 51.3% (39/76), including 31 cases with extra-abdominal involvement. Histopathologic subtypes included hyaline vascular variant (HVV), plasma cell variant (PCV), mixed HVV/PCV, and HHV-8 variant in 39, 25, 3 and 9 cases, respectively. The dominant nodal mass measured 4.4 ± 1.9 cm and 3.2 ± 1.7 cm in mean long- and short-axis, respectively, and appeared hypervascular in 58.6% (41/70 with IV contrast). Internal calcification was seen in 22.4% (17/76). Infiltration of the perinodal fat, with or without hypertrophy, was present in 56.6% (43/76), more frequent with hypervascular vs. non-hypervascular nodal masses (80.5% vs. 20.7%; p < 0.001). Among HVV cases, 76.9% were unicentric, 71.1% appeared hypervascular, and 69.2% demonstrated perinodal fat infiltration. CONCLUSION: Hypervascular nodal masses demonstrating prominence and infiltration of perinodal fat at CT can suggest the specific diagnosis of Castleman disease, especially the hyaline vascular variant. ADVANCES IN KNOWLEDGE: Abdominopelvic nodal masses that demonstrate hypervascular enhancement and prominent infiltration of the perinodal fat at CT can suggest the diagnosis of Castleman disease, but nonetheless requires tissue sampling.

A Case Report of Uterine Torsion in a Postmenopausal Female with a Large Leiomyoma.

This case report discusses a diagnosis of uterine torsion in an 84-year-old woman who presented with five days of right lower quadrant abdominal pain, nausea, vomiting, constipation, and poor intake. Computed tomography (CT) imaging demonstrated a whorled configuration at the junction of the cervix and lower uterine segment, with the left gonadal vein crossing midline, and two previously known right leiomyomas now appearing on the left. These findings were consistent with the diagnosis of uterine torsion. She then underwent an urgent exploratory laparotomy, and the uterus was found to be dextroverted 270 degrees, with dark mottled purple tissue and engorged vessels. A supracervical hysterectomy and bilateral salpingo-oopherectomy were performed. Final pathology demonstrated extensive necrosis. This case reviews the classic presentation and imaging findings for the rare diagnosis of uterine torsion and options for management of both non-gravid and gravid patients.

Training the New Radiologists: Approaches for Education.

The field of Radiology is continually changing, requiring corresponding evolution in both medical student and resident training to adequately prepare the next generation of radiologists. With advancements in adult education theory and a deeper understanding of perception in imaging interpretation, expert educators are reshaping the training landscape by introducing innovative teaching methods to align with increased workload demands and emerging technologies. These include the use of peer and interdisciplinary teaching, gamification, case repositories, flipped-classroom models, social media, and drawing and comics. This publication aims to investigate these novel approaches and offer persuasive evidence supporting their incorporation into the updated Radiology curriculum.

Overexpression of CXCL5 is associated with poor survival in patients with pancreatic cancer.

Epithelial neutrophil-activating peptide-78 (CXCL5), a member of the CXC chemokine family, has been shown to be involved in angiogenesis, tumor growth, and metastasis. The objective of this study was to determine the relationship between CXCL5 expression and tumor progression in human pancreatic cancer and to elucidate the mechanism underlying CXCL5-mediated tumor angiogenesis and cancer growth. We report herein that CXCL5 is overexpressed in human pancreatic cancer compared with paired normal pancreas tissue. Overexpression of CXCL5 is significantly correlated with poorer tumor differentiation, advanced clinical stage, and shorter patient survival. Patients with pancreatic cancer and CXCL5 overexpression who underwent resection of cancer had a mean survival time 25.5 months shorter than that of patients who did not overexpress CXCL5. Blockade of CXCL5 or its receptor CXCR2 by small-interfering RNA knockdown or antibody neutralization attenuated human pancreatic cancer growth in a nude mouse model. Finally, we demonstrated that CXCL5 mediates pancreatic cancer-derived angiogenesis through activation of several signaling pathways, including protein kinase B (Akt), extracellular signal-regulated kinase (ERK), and signal transducer and activator of transcription (STAT) in human endothelial cells. These data suggest that CXCL5 is an important mediator of tumor-derived angiogenesis and that it may serve as a survival factor for pancreatic cancer. Blockade of either CXCL5 or CXCR2 may be a critical adjunct antiangiogenic therapy against pancreatic cancer.

Reduction of Peristalsis-Related Streak Artifacts on the Liver with Dual-Layer Spectral CT.

Background: Peristalsis-related streak artifacts on the liver compromise image quality and diagnostic accuracy. Purpose: To assess dual-layer spectral-detector computed tomography (CT) image reconstructions for reducing intestinal peristalsis-related streak artifacts on the liver. Methods: We retrospectively evaluated 220 contrast-enhanced abdominal dual-energy CT scans in 131 consecutive patients (mean age: 68 ± 10 years, 120 men) who underwent routine clinical dual-layer spectral-detector CT imaging (120 kVp, 40 keV, 200 keV, virtual non-contrast (VNC), iodine images). Two independent readers evaluated bowel peristalsis streak artifacts on the liver qualitatively on a five-point Likert scale (1 = none to 5 = severe) and quantitatively by depth of streak artifact extension into the liver and measurements of Hounsfield Unit and iodine concentration differences from normal liver. Artifact severity between image reconstructions were compared by Wilcoxon signed-rank and paired t-tests. Results: 12 scans were excluded due to missing spectral data, artifacts on the liver originating from metallic foreign materials, or oral contrast material. Streak artifacts on the liver were seen in 51/208 (25%) scans and involved the left lobe only in 49/51 (96%), the right lobe only in 0/51 (0%), and both lobes in 2/51 (4%) scans. Artifact frequency was lower in iodine than in 120 kVp images (scans 18/208 vs. 51/208, p < 0.001). Artifact severity was less in iodine than in 120 kVp images (median score 1 vs. 3, p < 0.001). Streak artifact extension into the liver was shorter in iodine than 120 kVp images (mean length 2 ± 4 vs. 12 ± 5 mm, p < 0.001). Hounsfield Unit and iodine concentration differed significantly between bright streak artifacts and normal liver in 120 kVp, 40 keV, 200 keV, and VNC images (p < 0.001, each), but not in iodine images (p = 0.23). Conclusion: Intestinal peristalsis-related streak artifacts commonly affect the left liver lobe at CT and can be substantially reduced by viewing iodine dual-energy CT image reconstructions.

The SCARD Fellowship Policy and the Abdominal Imaging Fellowship: A Follow-up Survey After the First Year.

RATIONALE AND OBJECTIVES: To assess resident and fellowship program director (PD) perceptions of the abdominal radiology fellowship application process following the first cycle in which an embargo on interviews until December 1, 2019 was set according to the Society of Chairs of Academic Radiology Departments (SCARD) timeline for the 2021-2022 abdominal imaging fellowship year. MATERIALS AND METHODS: Eligible study participants included fellowship PDs of all abdominal imaging programs in the United States and residents that attended the Society of Abdominal Radiology (SAR) 2020 Annual Meeting. A questionnaire was developed by content and survey experts, pilot tested, and administered from May to June 2020. RESULTS: A total of 39% (36/92) of all PDs and 30% (46/152) of all individuals identified as residents with valid email addresses that attended the SAR 2020 Annual Meeting responded to the survey with an overall response rate of 34%. Only 42% of PDs and 33% of residents supported moving to a match, while 62% of PDs and 70% of residents thought that a match would limit the autonomy of applicants. While most PDs and residents also agreed that the first iteration of the SCARD timeline allowed residents to make a more informed choice, the majority of PDs were dissatisfied with their experience. Most PDs and residents additionally want applications to be accepted no earlier than July and/or August of the R3 year (initial SCARD guidelines did not restrict timing), interviews to begin on November 1st or earlier of the R3 year (compared to December 1st set in the first iteration of the guidelines), and a gap of 2-4 weeks between the date of first interviews and notification of first offers (initial SCARD guidelines did not restrict timing). Lastly, an overwhelming majority of PDs and residents agreed that SAR should enforce the abdominal imaging fellowship application process. CONCLUSION: Following the first cycle of abdominal imaging fellowship applications conducted according to the SCARD guidelines, a majority of trainees and PDs felt the changes were favorable and were opposed to a formal match. Specific suggestions for improvement were elicited from stakeholders and will be incorporated for the next cycle.