CT imaging of intrauterine devices (IUD): expected findings, unexpected findings, and complications.

Intrauterine devices (IUDs) are a commonly used form of long-acting reversible contraception, which either contain copper or levonorgestrel to prevent pregnancy. Although symptomatic patients with indwelling IUDs may first undergo ultrasound to assess for device malposition and complications, IUDs are commonly encountered on CT in patients undergoing evaluation for unrelated indications. Frequently, IUD malposition and complications may be asymptomatic or clinically unsuspected. For these reasons, it is important for the radiologist to carefully scrutinize the IUD on any study in which it is encountered. To do so, the radiologist must recognize that normally positioned IUDs are located centrally within the uterine cavity. IUDs are extremely effective in preventing pregnancy, though inadvertent pregnancy risk is higher with malpositioned IUDs. Presence of fibroids or Mullerian abnormalities may preclude proper IUD placement. Radiologists play an important role in identifying complications when they arise and special considerations when planning for an IUD placement. There is a wide range of IUD malposition, affecting IUDs differently depending on the type of IUD and its mechanism of action. IUD malposition is the most common complication, but embedment and/or partial perforation can and can lead to difficulty when removed. Retained IUD fragments can result in continued contraceptive effect. Perforated IUDs do not typically cause intraperitoneal imaging findings.

Nongynecologic Findings Seen at Pelvic US.

Ultrasonography (US) is frequently the first imaging modality used to examine women with symptoms involving the pelvis. It is widely available and involves no exposure to ionizing radiation. Images can be acquired with a transabdominal, endovaginal, or translabial approach, and the use of video clips and three-dimensional reconstructions can be helpful. US is excellent for assessment of the uterus, ovaries, and adnexa. Occasionally, nongynecologic pelvic diseases arising from the gastrointestinal, genitourinary, and musculoskeletal systems and the pelvic peritoneal and extraperitoneal spaces may be detected and can be a source of diagnostic dilemma. US can be helpful not only in the detection but also occasionally in the characterization of such entities. Computed tomography and magnetic resonance imaging are useful in complicated cases. In this article, the normal US appearance of the bowel and US signs of bowel disease and specific entities, including appendicitis, diverticular disease, bowel obstruction, appendiceal mucocele, and intestinal tumors, are reviewed. The lower urinary tract is included in the field of view in every pelvic US examination; commonly encountered entities related to the urinary bladder, distal ureter, and urethra are illustrated. In addition to arising in the gastrointestinal and genitourinary tracts, pathologic conditions in the pelvis can arise in the peritoneal or extraperitoneal space. Although conditions of the pelvic peritoneal and extraperitoneal spaces are rare, it is important to recognize these entities and distinguish them from the more common gynecologic diseases. Owing to the implications for diagnosis and management, radiologists and other physicians who perform pelvic US should be aware of the spectrum of nongynecologic pathologic entities that can be detected. ©RSNA, 2017.

MR Imaging of Müllerian Fusion Anomalies.

Müllerian duct anomalies, also called congenital uterine anomalies, are developmental structural disorders of the female genital tract. These anomalies are clinically relevant in patients with a history of infertility and pregnancy-related complications. The American Society for Reproductive Medicine classification system is the most well known, although newer systems, such as from the European Society of Human Reproduction and Embryology/European Society for Gynaecological Endoscopy, are becoming more widely accepted. MR imaging remains the optimal imaging modality due to its superior multiplanar capability and spatial resolution. This review article describes the typical MR appearance of congenital uterine anomalies.

Beyond the Bowel: Extraintestinal Manifestations of Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) is a chronic, relapsing immune-mediated inflammation of the gastrointestinal tract. IBD includes two major disease entities: Crohn disease and ulcerative colitis. Imaging plays an important role in the diagnosis and surveillance of these complex disorders. Computed tomographic and magnetic resonance enterographic techniques have been refined in recent years to provide a superb means of evaluating the gastrointestinal tract for suspected IBD. Although the intestinal imaging manifestations of IBD have been extensively discussed in the radiology literature, extraintestinal imaging manifestations of IBD have received less attention. Multiple extraintestinal manifestations may be seen in IBD, including those of gastrointestinal (hepatobiliary and pancreatic), genitourinary, musculoskeletal, pulmonary, cardiac, ocular, and dermatologic disorders. Although many associations between IBD and extraintestinal organ systems have been well established, other associations have not been fully elucidated. Some extraintestinal disorders may share a common pathogenesis with IBD. Other extraintestinal disorders may occur as a result of unintended treatment-related complications of IBD. Although extraintestinal disorders within the abdomen and pelvis may be well depicted with cross-sectional enterography, other musculoskeletal and thoracic disorders may be less evident with such examinations and may warrant further investigation with additional imaging examinations or may be readily apparent from the findings at physical examination. Radiologists involved in the interpretation of IBD imaging examinations must be aware of potential extraintestinal manifestations, to provide referring clinicians with an accurate and comprehensive profile of patients with these complex disorders. © RSNA, 2017.

Heterotopic Pancreas: Histopathologic Features, Imaging Findings, and Complications.

Heterotopic pancreas is a congenital anomaly in which pancreatic tissue is anatomically separate from the main gland. The most common locations of this displacement include the upper gastrointestinal tract-specifically, the stomach, duodenum, and proximal jejunum. Less common sites are the esophagus, ileum, Meckel diverticulum, biliary tree, mesentery, and spleen. Uncomplicated heterotopic pancreas is typically asymptomatic, with the lesion being discovered incidentally during an unrelated surgery, during an imaging examination, or at autopsy. The most common computed tomographic appearance of heterotopic pancreas is that of a small oval intramural mass with microlobulated margins and an endoluminal growth pattern. The attenuation and enhancement characteristics of these lesions parallel their histologic composition. Acinus-dominant lesions demonstrate avid homogeneous enhancement after intravenous contrast material administration, whereas duct-dominant lesions are hypovascular and heterogeneous. At magnetic resonance imaging, the heterotopic pancreas is isointense to the orthotopic pancreas, with characteristic T1 hyperintensity and early avid enhancement after intravenous gadolinium-based contrast material administration. Heterotopic pancreatic tissue has a rudimentary ductal system in which an orifice is sometimes visible at imaging as a central umbilication of the lesion. Complications of heterotopic pancreas include pancreatitis, pseudocyst formation, malignant degeneration, gastrointestinal bleeding, bowel obstruction, and intussusception. Certain complications may be erroneously diagnosed as malignancy. Paraduodenal pancreatitis is thought to be due to cystic degeneration of heterotopic pancreatic tissue in the medial wall of the duodenum. Recognizing the characteristic imaging features of heterotopic pancreas aids in differentiating it from cancer and thus in avoiding unnecessary surgery. © RSNA, 2017.

Gestational Trophoblastic Disease: Clinical and Imaging Features.

Gestational trophoblastic disease (GTD) is a spectrum of both benign and malignant gestational tumors, including hydatidiform mole (complete and partial), invasive mole, choriocarcinoma, placental site trophoblastic tumor, and epithelioid trophoblastic tumor. The latter four entities are referred to as gestational trophoblastic neoplasia (GTN). These conditions are aggressive with a propensity to widely metastasize. GTN can result in significant morbidity and mortality if left untreated. Early diagnosis of GTD is essential for prompt and successful management while preserving fertility. Initial diagnosis of GTD is based on a multifactorial approach consisting of clinical features, serial quantitative human chorionic gonadotropin (ß-hCG) titers, and imaging findings. Ultrasonography (US) is the modality of choice for initial diagnosis of complete hydatidiform mole and can provide an invaluable means of local surveillance after treatment. The performance of US in diagnosing all molar pregnancies is surprisingly poor, predominantly due to the difficulty in differentiating partial hydatidiform mole from nonmolar abortion and retained products of conception. While GTN after a molar pregnancy is usually diagnosed with serial ß-hCG titers, imaging plays an important role in evaluation of local extent of disease and systemic surveillance. Imaging also plays a crucial role in detection and management of complications, such as uterine and pulmonary arteriovenous fistulas. Familiarity with the pathogenesis, classification, imaging features, and treatment of these tumors can aid in radiologic diagnosis and guide appropriate management. ©RSNA, 2017.

Organ-confined prostate cancer: effect of prior transrectal biopsy on endorectal MRI and MR spectroscopic imaging.

OBJECTIVE: Our aim was to determine the effect of prior transrectal biopsy on endorectal MRI and MR spectroscopic imaging findings in patients with organ-confined prostate cancer. MATERIALS AND METHODS: Endorectal MRI and MR spectroscopic imaging were performed in 43 patients with biopsy-proven prostate cancer before radical prostatectomy confirming organ-confined disease. For each sextant, two independent reviewers scored the degree of hemorrhage on a scale from 1 to 5 and recorded the presence or absence of capsular irregularity. A spectroscopist recorded the number of spectrally degraded voxels in the peripheral zone. The outcome variables of capsular irregularity and spectral degradation were correlated with the predictor variables of time from biopsy and degree of hemorrhage after biopsy. RESULTS: Capsular irregularity was unrelated to time from biopsy or to degree of hemorrhage. Spectral degradation was inversely related to time from biopsy (p < 0.01); the mean percentage of degraded peripheral zone voxels was 18.5% within 8 weeks of biopsy compared with 7% after 8 weeks. Spectral degradation was unrelated to the degree of hemorrhage. CONCLUSION: In organ-confined prostate cancer, capsular irregularity can be seen at any time after biopsy and is independent of the degree of hemorrhage, whereas spectral degradation is seen predominantly in the first 8 weeks after biopsy. MRI staging criteria and guidelines for scheduling studies after biopsy may require appropriate modification.