Ectopic pregnancy: a resident's guide to imaging findings and diagnostic pitfalls.

Ectopic pregnancy (EP) is a term used to describe any pregnancy which does not implant into the uterine cavity. There are several types of EPs: tubal, interstitial, ovarian, abdominal, heterotopic, cervical, and cesarean scar. Ectopic pregnancies can acutely rupture and are the number one cause of maternal death in the first trimester of pregnancy. Therefore, prompt recognition and accurate localization have significant clinical implications on patient outcome. Unfortunately, EPs have many mimickers, which can make the diagnosis challenging in certain cases. In this review, we aim to describe and illustrate sonographic findings of each type of EP, as well as present mimickers and various imaging pitfalls. We will clarify how to avoid potential misdiagnoses that could adversely affect patient outcomes. Lastly, we will briefly address management of each type of EP and discuss potential complications.

Prevalence of Low-Attenuation Homogeneous Papillary Renal Cell Carcinoma Mimicking Renal Cysts on CT.

OBJECTIVE: The objective of our study was to determine the attenuation range of homogeneous papillary renal cell carcinomas (RCCs) on contrast-enhanced CT. MATERIALS AND METHODS: This retrospective study was performed at two institutions from January 1, 2007, to January 1, 2017. Multiphasic CT studies with and without IV contrast material of 114 patients with pathologically proven papillary RCCs were independently reviewed by two sets of two abdominal radiologists. Seventy-two cases were excluded because of subjective lesion heterogeneity, leaving 42 homogeneous RCCs. Three ROIs were placed on all lesions for all CT phases, and the mean attenuations were calculated. RESULTS: Mean lesion size was 2.8 cm (range, 1.2-11.0 cm). The attenuation range for each CT phase was as follows: unenhanced, 14.7-50.7 HU; corticomedullary, 32.2-99.5 HU; portal venous, 40.8-95.1 HU; nephrographic, 17.9-90.8 HU; and excretory, 18.0-73.0 HU. Two of 114 (1.8%; 95% CI, 0.2-6.5%) RCCs were homogeneous and less than 30 HU on the portal venous or nephrographic phase. One of these RCCs was a solid hypoenhancing mass, and the other was a homogeneous cystic RCC. Of the cases with an unenhanced phase, three of 107 (2.8%; 95% CI, 0.6-8.8%) were both homogeneous and were less than 20 HU in attenuation. CONCLUSION: Papillary RCCs are rarely both subjectively homogeneous and less than 20 HU at unenhanced CT and less than 30 HU at portal venous or nephrographic phase CT.

Imaging Pregnant and Lactating Patients.

As use of imaging in the evaluation of pregnant and lactating patients continues to increase, misperceptions of radiation and safety risks have proliferated, which has led to often unwarranted concerns among patients and clinicians. When radiologic examinations are appropriately used, the benefits derived from the information gained usually outweigh the risks. This review describes appropriateness and safety issues, estimated doses for imaging examinations that use iodizing radiation (ie, radiography, computed tomography, nuclear scintigraphy, and fluoroscopically guided interventional radiology), radiation risks to the mother and conceptus during various stages of pregnancy, and use of iodinated or gadolinium-based contrast agents and radiotracers in pregnant and lactating women. Maternal radiation risk must be weighed with the potential consequences of missing a life-threatening diagnosis such as pulmonary embolus. Fetal risks (ie, spontaneous abortion, teratogenesis, or carcinogenesis) vary with gestational age and imaging modality and should be considered in the context of the potential benefit of medically necessary diagnostic imaging. When feasible and medically indicated, modalities that do not use ionizing radiation (eg, magnetic resonance imaging) are preferred in pregnant and lactating patients. Radiologists should strive to minimize risks of radiation to the mother and fetus, counsel patients effectively, and promote a realistic understanding of risks related to imaging during pregnancy and lactation.

CT of acute perianal abscesses and infected fistulae: a pictorial essay.

Computed tomography (CT) is an effective, readily available diagnostic imaging tool for evaluation of the emergency room (ER) patients with the clinical suspicion of perianal abscess and/or infected fistulous tract (anorectal sepsis). These patients usually present with perineal pain, fever, and leukocytosis. The diagnosis can be easy if the fistulous tract or abscess is visible on inspection of the perianal skin. If the tract or abscess is deep, then the clinical diagnosis can be difficult. Also, the presence of complex tracts or supralevator extension of the infection cannot be judged by external examination alone. Magnetic resonance imaging (MRI) is the best imaging test to accurately detect fistulous tracts, especially when they are complex (Omally et al. in AJR 199:W43-W53, 2012). However, in the acute setting in the ER, this imaging modality is not always immediately available. Endorectal ultrasound has also been used to identify perianal abscesses, but this modality requires hands-on expertise and can have difficulty localizing the offending fistulous tract. It may also require the use of a rectal probe, which the patient may not be able to tolerate. Contrast-enhanced CT is a very useful tool to diagnose anorectal sepsis; however, this has not received much attention in the recent literature (Yousem et al. in Radiology 167(2):331-334, 1988) aside from a paper describing CT imaging following fistulography (Liang et al. in Clin Imaging 37(6):1069-1076, 2013). An infected fistula is indicated by a fluid-/air-filled soft tissue tract surrounded by inflammation. A well-defined round to oval-shaped fluid/air collection is indicative of an abscess. The purpose of this article is to demonstrate the usefulness of contrast-enhanced CT in the diagnosis of acute anorectal sepsis in the ER setting. We will discuss the CT appearance of infected fistulous tracts and abscesses and how CT imaging can guide the ER physician in the clinical management of these patients.

De-misty-fying the mesentery: an algorithmic approach to neoplastic and non-neoplastic mesenteric abnormalities.

Mesenteric abnormalities are often incidentally discovered on cross-sectional imaging performed during daily clinical practice. Findings can range from the vague "misty mesentery" to solid masses, and the possible etiologic causes encompass a wide spectrum of underlying pathologies including infectious, inflammatory, and neoplastic processes. Unfortunately, the clinical and imaging findings are often non-specific and may overlap. This article discusses the various diseases that result in mesenteric abnormalities. It provides a framework to non-invasively differentiate these entities, when possible.

Ultrasound-guided lymph node fine-needle aspiration for evaluating post-vaccination germinal center responses in humans.

The lymph node (LN) is a critical biological site for immune maturation after vaccination as it includes several cell populations critical for priming the antibody response. Here, we present a protocol for sampling the LN and isolating cell populations to evaluate immunogens targeting germline cells. We describe steps for media and tube preparation and sample collection using an ultrasound-guided LN fine-needle aspiration procedure. This protocol is safe, quick, low-cost, and less invasive than excisional biopsy. For complete details on the use and execution of this protocol, please refer to Leggat et al. (2022).1.

The unicornuate uterus and its variants: clinical presentation, imaging findings, and associated complications.

This article will describe the different variants of the unicornuate uterus, their clinical presentation and imaging findings, as well their associated complications. We will also review the associated renal anomalies. Patients' symptoms and their imaging findings will vary depending on the unicornuate subtype. Radiologic evaluation includes a combination of hysterosalpingography, sonography, and magnetic resonance imaging. Complications include obstetric ones related to the small uterine size and endometriosis and ectopic pregnancies when a cavitary rudimentary uterine horn is present. Radiologists should be familiar with all variants of the unicornuate uterus as well as their clinical presentation and associated imaging findings.

Multimodality imaging of the essure permanent birth control device: emphasis on commonly overlooked abnormalities.

OBJECTIVE: The purpose of this pictorial essay is to review the imaging findings of normally and abnormally positioned Essure permanent birth control devices across the different imaging techniques and to show common sites of device migration. CONCLUSION: The Essure device is easily visualized on all imaging techniques, and radiologists should be familiar with its appearance and be able to identify cases of device migration on ultrasound and hysterosalpingography that would suggest malfunction.

The Rare, the Odd, and the Atypical: A Pictorial Essay of Testicular and Paratesticular Diseases.

ABSTRACT: Understanding a variety of scrotal diseases is essential to developing an accurate differential diagnosis and is critical in providing optimal patient care. Ultrasound is the imaging modality of choice when evaluating for scrotal pathology, with the major purpose of locating such pathology to either the testis, or epididymis, or other intrascrotal structures, as well as characterizing lesions as solid or cystic. It is generally assumed that most solid intratesticular masses are more likely malignant, whereas most extratesticular ones are benign, although some exceptions to that rule exist. This pictorial essay will focus on rare and less commonly encountered benign and malignant testicular and paratesticular pathologies, which may pose a diagnostic dilemma for interpreting radiologists and treating physicians. Knowledge of their imaging characteristics will help narrow the differential diagnosis and assist in proper patient management and care.

Imaging of Benign Adnexal Disease.

This article provides an overview of the imaging evaluation of benign ovarian and adnexal masses in premenopausal and postmenopausal women and lesions discovered during pregnancy. Current imaging techniques are discussed, including pitfalls and differential diagnosis when necessary, as well as management. It also reviews the now well-established American College of Radiology (ACR)/Society of Radiologists in Ultrasound consensus guidelines and covers the more recently introduced Ovarian-Adnexal Reporting and Data System by the ACR and the recently published ADNEx Scoring System.

Imaging of Infertility, Part 1: Hysterosalpingograms to Magnetic Resonance Imaging.

Infertility, or subfertility, is the inability to achieve a clinical pregnancy after a 1-year period of regular unprotected sexual intercourse in women younger than 35 and after 6 months in women older than 35. Although initial assessment involves a multitude of factors, including a detailed medical history, physical examination, semen analysis, and hormonal evaluation, diagnostic imaging of the female partner often plays an important role in establishing the etiology for infertility. This article provides an overview of the multimodality imaging assessment of female infertility and details the developmental and acquired pelvic abnormalities in which diagnostic imaging aids in evaluation.

Imaging of Infertility, Part 2: Hysterosalpingograms to Magnetic Resonance Imaging.

Infertility, or subfertility, is the inability to achieve a clinical pregnancy after a 1-year period of regular unprotected sexual intercourse in women younger than 35 and after 6 months in women older than 35. Although initial assessment involves a multitude of factors, including a detailed medical history, physical examination, semen analysis, and hormonal evaluation, diagnostic imaging of the female partner often plays an important role in establishing the etiology for infertility. This article provides an overview of the multimodality imaging assessment of female infertility and details the developmental and acquired pelvic abnormalities in which diagnostic imaging aids in evaluation.

ACR Appropriateness Criteria® Multiple Gestations.

Women with twin or higher-order pregnancies will typically have more ultrasound examinations than women with a singleton pregnancy. Most women will have at minimum a first trimester scan, a nuchal translucency evaluation scan, fetal anatomy scan at 18 to 22 weeks, and one or more scans in the third trimester to evaluate growth. Multiple gestations are at higher risk for preterm delivery, congenital anomalies, fetal growth restriction, placenta previa, vasa previa, and velamentous cord insertion. Chorionicity and amnionicity should be determined as early as possible when a twin pregnancy is identified to permit triage of the monochorionic group into a closer surveillance model. Screening for congenital heart disease is warranted in monochorionic twins because they have an increased rate of congenital cardiac anomalies. In addition, monochorionic twins have a higher risk of developing cardiac abnormalities in later gestation related to right ventricular outflow obstruction, in particular the subgroups with twin-twin transfusion syndrome or selective intrauterine growth restriction. Monochorionic twins have unique complications including twin-to-twin transfusion syndrome, twin embolization syndrome, and acardius, or twin-reversed arterial perfusion sequence. 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 include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria Assessment of Fetal Well-Being.

Although there is limited evidence that antepartum testing decreases the risk for fetal death in low-risk pregnancies, women with high-risk factors for stillbirth should undergo antenatal fetal surveillance. The strongest evidence supporting antepartum testing pertains to pregnancies complicated by intrauterine fetal growth restriction secondary to uteroplacental insufficiency. The main ultrasound-based modalities to determine fetal health are the biophysical profile, modified biophysical profile, and duplex Doppler velocimetry. In patients at risk for cardiovascular compromise, fetal echocardiography may also be indicated to ensure fetal well-being. Although no single antenatal test has been shown to be superior, all have high negative predictive values. Weekly or twice-weekly fetal testing has become the standard practice in high-risk pregnancies. The timing for the initiation of assessments of fetal well-being should be tailored on the basis of the risk for stillbirth and the likelihood of survival with intervention. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (the RAND/UCLA Appropriateness Method and the Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The role of ultrasound in renal insufficiency: the essentials.

Sonography is the best screening modality to evaluate patients presenting with renal insufficiency. Ultrasound findings can be normal in patients with renal disease, especially in prerenal azotemia and acute parenchymal renal disease. Echogenic kidneys indicate the presence of parenchymal renal disease; the kidneys may be of a normal size or enlarged. Small kidneys suggest advanced stage chronic kidney disease. Uncommonly, cystic disease of the kidney, especially adult type polycystic kidney disease may be the cause of the patient's renal insufficiency with bilaterally enlarged kidneys containing multiple cysts of various sizes. If hydronephrosis is present, the level and cause of the obstruction should be sought. When ultrasound cannot diagnose the level and cause of obstruction, other imaging modalities, including CT and MRI may be useful. When renovascular disease (arterial stenosis or venous thrombosis) is suspected, spectral and color Doppler can be useful in detecting abnormalities.

ACR Appropriateness Criteria pelvic floor dysfunction.

Pelvic floor dysfunction is a common and potentially complex condition. Imaging can complement physical examination by revealing clinically occult abnormalities and clarifying the nature of the pelvic floor defects present. Imaging can add value in preoperative management for patients with a complex clinical presentation, and in postoperative management of patients suspected to have recurrent pelvic floor dysfunction or a surgical complication. Imaging findings are only clinically relevant if the patient is symptomatic. Several imaging modalities have a potential role in evaluating patients; the choice of modality depends on the patient's symptoms, the clinical information desired, and the usefulness of the test. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions; they are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals, and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

ACR appropriateness Criteria® infertility.

Appropriate imaging for women undergoing infertility workup depends upon the clinician's suspicion for potential causes of infertility. Transvaginal US is the preferred modality to assess the ovaries for features of polycystic ovary syndrome (PCOS), the leading cause of anovulatory infertility. For women who have a history or clinical suspicion of endometriosis, which affects at least one third of women with infertility, both MRI and pelvic US can provide valuable information. If tubal occlusion is suspected, whether due to endometriosis, previous pelvic inflammatory disease, or other cause, hysterosalpingogram (HSG) is the preferred method of evaluation. To assess for anatomic causes of recurrent pregnancy loss (RPL) such as Müllerian anomalies, synechiae, and leiomyomas, saline infusion sonohysterography, MRI and 3-D US are most appropriate. Up to 10% of women suffering recurrent pregnancy loss have a congenital Müllerian anomaly. When assessment of the pituitary gland is indicated, MRI is the imaging exam of choice.The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Ultrasound of the scrotum.

Ultrasound plays an important role in the diagnostic workup of scrotal diseases. It can differentiate a testicular mass from an extratesticular mass and determine whether the mass is cystic, solid, or complex. Using this information a likely diagnosis can be ascertained. In the acute scrotum, acute epididymitis/epididymo-orchitis can in most cases be distinguished from testicular torsion. Following scrotal trauma, surgery is needed to salvage the testis if there is testicular disruption and ultrasound can help with this diagnostic dilemma. When a large hydrocele is present, ultrasound allows evaluation of the underlying testis and epididymis and it can detect varicoceles, especially in the infertile male. In patients at risk for a testicular tumor (cryptorchid testis, testicular microlithiasis), ultrasound is the best imaging modality for follow-up. CT, MRI, and nuclear medicine scanning may be necessary for further evaluation of scrotal diseases and this will be briefly addressed.

ACR appropriateness Criteria® second and third trimester bleeding.

Vaginal bleeding occurring in the second or third trimesters of pregnancy can variably affect perinatal outcome, depending on whether it is minor (i.e. a single, mild episode) or major (heavy bleeding or multiple episodes.) Ultrasound is used to evaluate these patients. Sonographic findings may range from marginal subchorionic hematoma to placental abruption. Abnormal placentations such as placenta previa, placenta accreta and vasa previa require accurate diagnosis for clinical management. In cases of placenta accreta, magnetic resonance imaging is useful as an adjunct to ultrasound and is often appropriate for evaluation of the extent of placental invasiveness and potential involvement of adjacent structures. MRI is useful for preplanning for cases of complex delivery, which may necessitate a multi-disciplinary approach for optimal care.The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every two years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.