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Compression of the left renal vein by the superior mesenteric artery, known as nutcracker phenomenon (NCP), can cause retrograde flow and congestion in communicating venous systems. It has recently been speculated that NCP can result in retrograde flow and congestion of the lumbar veins and epidural venous plexus (EVP), thereby affecting the central nervous system. This study describes the novel use of time-resolved magnetic resonance angiography (trMRA) to evaluate for retrograde left second lumbar vein (L2LV) flow and early EVP enhancement in patients with chronic daily headache (CDH) with and without NCP.A retrospective analysis was performed of 31 patients with CDH (27 females and 4 males; median age, 38 years [range, 18-63 years]) who underwent trMRA centered over the L2LV to evaluate the direction of blood flow and presence of early EVP enhancement from May 2020 to March 2022. Descriptive statistics were performed, and anatomic associations were analyzed in patients with and without retrograde L2LV flow and early EVP enhancement. The accuracy of magnetic resonance imaging findings in detecting these flow patterns was also assessed.Patients with NCP who demonstrated narrowing of the left renal vein, a positive beak sign (P = 0.052), decreased aortomesenteric distance (P = 0.038), and decreased SMA angle demonstrated increased rates of retrograde L2LV flow and early EVP enhancement. A positive beak sign was 83% specific, and an aortomesenteric distance of ≤6.5 mm was 61% sensitive and 83% specific for identifying retrograde L2LV flow with early regional EVP enhancement in patients with CDH.Retrograde L2LV flow with early EVP enhancement in CDH patients can be effectively evaluated using trMRA and was seen with greater propensity in those patients with NCP.

Medical simulation training can be used to improve clinician performance, teach communication and professionalism skills, and enhance team training. Radiology residents can benefit from simulation training in diagnostic ultrasound, procedural ultrasound, and communication skills prior to direct patient care experiences. This paper details a weeklong ultrasound simulation training curriculum for radiology residents during the PGY-1 clinical internship. The organization of established teaching methods into a dedicated course early in radiology residency training with the benefit of a multi-disciplinary approach makes this method unique. This framework can be adapted to fit learners at different skill levels or with specific procedural needs.

Focal nodular hyperplasia (FNH) is a benign lesion occurring in a background of normal liver. FNH is seen most commonly in young women and can often be accurately diagnosed at imaging, including CT, MRI, or contrast-enhanced US. In the normal liver, FNH frequently must be differentiated from hepatocellular adenoma, which although benign, is managed differently because of the risks of hemorrhage and malignant transformation. When lesions that are histologically identical to FNH occur in a background of abnormal liver, they are termed FNH-like lesions. These lesions can be a source of diagnostic confusion and must be differentiated from malignancies. Radiologists' familiarity with the imaging appearance of FNH-like lesions and knowledge of the conditions that predispose a patient to their formation are critical to minimizing the risks of unnecessary intervention for these lesions, which are rarely symptomatic and carry no risk for malignant transformation. FNH is thought to form secondary to an underlying vascular disturbance, a theory supported by the predilection for formation of FNH-like lesions in patients with a variety of hepatic vascular abnormalities. These include abnormalities of hepatic outflow such as Budd-Chiari syndrome, abnormalities of hepatic inflow such as congenital absence of the portal vein, and hepatic microvascular disturbances, such as those that occur after exposure to certain chemotherapeutic agents. Familiarity with the imaging appearances of these varied conditions and knowledge of their association with formation of FNH-like lesions allow radiologists to identify with confidence these benign lesions that require no intervention.

Contrast-enhanced US (CEUS), similar to other radiologic modalities, requires specific technical considerations and is subject to image artifacts. These artifacts may affect examination quality, negatively impact diagnostic accuracy, and decrease user comfort when using this emerging technique. Some artifacts are related to commonly known gray-scale US artifacts that can also appear on the contrast-only image (tissue-subtracted image obtained with the linear responses from background tissues nulled). These may include acoustic shadowing and enhancement; reverberation, refraction, and reflection; and poor penetration. Other artifacts are exclusive to CEUS owing to the techniques used for contrast mode image generation and the unique properties of the microbubbles that constitute ultrasound-specific contrast agents (UCAs). UCA-related artifacts may appear on the contrast-only image, the gray-scale image, or various Doppler mode images. Artifacts related to CEUS may include nonlinear artifacts and unintentional microbubble destruction resulting in pseudowashout. The microbubbles themselves may result in specific artifacts such as pseudoenhancement, signal saturation, and attenuation and shadowing and can confound the use of color and spectral Doppler US. Identifying and understanding these artifacts and knowing how to mitigate them may improve the quality of the imaging study, increase user confidence, and improve patient care. The authors review the principles of UCAs and the sound-microbubble interaction, as well as the technical aspects of image generation. Technical considerations, including patient positioning, depth, acoustic window, and contrast agent dose, also are discussed. Specific artifacts are described, with tips on how to identify and, if necessary, apply corrective measures, with the goal of improving examination quality.

The authors provide a commentary on the current status of the Abdominal Radiology Fellowship recruitment process, which is not presently governed by a formal Match. Abdominal Radiology is the largest radiology subspecialty fellowship that remains outside of the Match. The Society of Abdominal Radiology convened a task force in 2019 to assess stakeholder viewpoints on a Match and found that the community was divided. Radiology departments and Abdominal Radiology fellowship program directors have voluntarily complied with a series of guidelines laid out by the Society of Chairs in Academic Radiology Departments during the two most recent recruiting cycles, but challenges in the process persist. Stakeholders report improved organization and fairness as a result of these procedural changes, and the authors suggest that Abdominal Radiology may continue to consider a formal fellowship Match in coming years.

Ruptured abdominal aortic aneurysm (AAA) carries high morbidity and mortality. Elective repair of AAA with endovascular stent-grafts requires lifetime imaging surveillance for potential complications, most commonly endoleaks. Because endoleaks result in antegrade or retrograde systemic arterialized flow into the excluded aneurysm sac, patients are at risk for recurrent aneurysm sac growth with the potential to rupture. Multiphasic CT has been the main imaging modality for surveillance and symptom evaluation, but contrast-enhanced US (CEUS) offers a useful alternative that avoids radiation and iodinated contrast material. CEUS is at least equivalent to CT for detecting endoleak and may be more sensitive. The authors provide a general protocol and technical considerations needed to perform CEUS of the abdominal aorta after endovascular stent repair. When there are no complications, the stent-graft lumen has homogeneous enhancement, and no contrast material is present in the aneurysm sac outside the stented lumen. In patients with an antegrade endoleak, contrast material is seen simultaneously in the aneurysm sac and stent-graft lumen, while delayed enhancement in the sac is due to retrograde leak. Recognition of artifacts and other potential pitfalls for CEUS studies is important for examination performance and interpretation.

Thyroid ultrasound with gray-scale and color Doppler is the most helpful imaging modality to differentiate normal thyroid parenchyma from diffuse or nodular thyroid disease by evaluating glandular size, echogenicity, echotexture, margins, and vascularity. The various causes of diffuse thyroid disease often have overlapping sonographic imaging features. Thyroid nodules may be hyperplastic or neoplastic, with most due to benign hyperplastic changes in architecture and benign follicular adenomas; only a small percentage are malignant. A systematic approach to nodule morphology that includes evaluation of composition, echogenicity, margin, shape, and any echogenic foci can guide decision to biopsy or follow nodules.

Hemangioma is the most common benign liver tumor and is frequently encountered as an incidental finding on imaging. The classic enhancement pattern of hemangioma is diagnostic on contrast-enhanced ultrasound (CEUS), and it follows the same pattern of enhancement on computed tomography and magnetic resonance imaging. However, there is a subset of hemangiomas that demonstrate atypical enhancement patterns on CEUS. The ability to recognize the different enhancement patterns and discern when additional imaging or biopsy may be necessary is essential to accurately interpret an atypical hemangioma on CEUS. This article reviews various enhancement patterns of hemangioma on CEUS to avoid pitfalls in characterization of focal liver lesions on CEUS.

Endovaginal sonographic imaging has been shown to reliably identify pelvic endometriosis, but most United States imaging practices do not adequately assess locations and features of endometriosis beyond ovarian endometrioma. In this article, we propose a protocol for sonographer-acquired images and maneuvers to be interpreted subsequently by sonologists (radiologists or gynecologists). The purpose is to improve the sensitivity of endovaginal sonography for the detection of endometriosis in imaging practices that involve the non-physician sonographer as part of their workflow.

To determine if a specific population of patients with a daily persistent headache from onset have underlying nutcracker physiology and to propose a pathogenesis model for their headaches utilizing a novel MRI protocol.A single case report of a daily persistent headache associated with nutcracker syndrome was recently published. As the left renal vein has a connection to the spinal lumbar veins and secondarily to the spinal epidural venous plexus, one could hypothesize that renal vein compression could lead to persistent headache by altering spinal and cerebral venous pressure with secondary alterations in CSF pressure. The authors have published on a series of patients with a unique subtype of daily persistent headache from onset that appears to be caused by an abnormal reset of CSF pressure to an elevated state. The goal of the present study was to look for the presence of nutcracker physiology in this unique patient subgroup and to propose a pathogenesis model utilizing a novel MRI protocol to evaluate for retrograde lumbar vein flow and regional spinal epidural venous plexus congestion.Case series of patients with a daily persistent headache from onset, head pressure, and whose headaches worsened in the Trendelenburg position. Patients were imaged with a 3 T MRI in the supine position from the lower diaphragm to the top of the pelvis with a dynamic angiogram centered over the left L2 lumbar vein.12 patients were studied of which 8 were positive for left renal vein compression, lumbar vein dilation and early spinal epidural venous plexus enhancement. All were women. Mean age of headache onset was 39 years. Six of the 8 patients had a lumbar puncture, and all had a normal opening pressure. All improved with CSF volume removal although pain resolution lasted from hours to 6 months. The patient's headaches were marked by holocranial pressure and the majority displayed migrainous associated symptoms although none had a prior headache history. They did not complain of typical symptoms or signs of nutcracker syndrome.We suggest that patients with a daily persistent headache from onset who worsen in the Trendelenburg position may have underlying nutcracker physiology. From our imaging findings, it can be hypothesized that left renal vein compression leads to retrograde flow through the valveless lumbar vein which then leads to spinal epidural venous congestion and subsequently causes congestion of the cerebral venous system leading to an elevation of CSF pressure and to a daily headache. What appears to be unique about these patients is that a daily headache is their only manifestation of nutcracker physiology.

Crizotinib is a tyrosine kinase inhibitor that has been found to be effective in the treatment of anaplastic lymphoma kinase (ALK) positive non-small cell lung cancer. This targeted cancer therapy agent has been shown to have superior efficacy over standard chemotherapy in this small subset of lung cancer patients. An adverse effect of this drug therapy is the development of complex renal cysts. Here, we present a case of a 68-year-old patient with non-small cell lung cancer on Crizotinib therapy who developed complex bilateral renal cysts. It is important to recognize this drug-related complication in order to avoid mistaking it for disease progression, primary renal malignancy, or renal infection.

Ultrasound (US)-guided intervention is a well-established medical procedure and offers advantages such as real-time guidance, portability, reduced cost, shortened procedure time compared with computed tomography, and lack of ionizing radiation. Ultrasound contrast agents (UCAs) are a useful adjunct to US-guided procedures. The addition of microbubble UCAs during US-guided interventions can assist with biopsy planning and lesion selection, aid in identification of target lesions, and direct the biopsy toward viable tissue. Ultrasound contrast agents have been in use outside of the United States for many years and have been used off label at select institutions across the United States before the Food and Drug Administration approval of Lumason (Bracco Diagnostics) for liver lesion evaluation in April 2016. After Food and Drug Administration approval, the use of UCAs has expanded rapidly, and UCAs are being used for a variety of clinical applications. Ultrasound contrast agents have been shown to be safe, and there is no renal toxicity. In this article, we will discuss the indications and techniques for using contrast-enhanced ultrasound during US-guided interventions, and we will present case examples where contrast-enhanced ultrasound added value.

Transformation of benign endometriosis to endometriosis-associated ovarian carcinoma (EAOC) is rare; however, women with endometriosis are four times more likely to develop EAOC which can present 20 years earlier than de novo ovarian cancer. Presenting symptoms are often vague and the radiologist’s role in recognizing EAOC is critical for early detection and treatment. Histopathologic evaluation remains the mainstay for definitive diagnosis. Using a case-based approach, this article will review the sonographic, CT, and MRI features of EAOC with an emphasis on MRI. Histopathologic correlation of benign and malignant endometriosis will be reviewed. Multiple factors contribute to the malignant transformation of endometriosis including genetic alterations, hormonal influences, oxidative stress, and inflammation. Malignancy most often occurs in ovarian endometriomas with less common sites involving the rectovaginal septum, rectosigmoid colon, and abdominal wall scars. The most common pathologic subtypes are endometrioid adenocarcinoma and clear cell carcinoma. MRI is the most specific imaging modality for evaluating EAOC. Key MR features include solid enhancing nodules (accentuated by subtraction imaging), nodular septations, loss of T2 shading within the endometrioma, and diffusion restriction. EAOC is a distinct disease that affects women with benign endometriosis at younger ages than classic ovarian cancer. Understanding the imaging features of malignant transformation of endometriosis is essential for early diagnosis and timely definitive treatment.

Thyroid ultrasound with gray-scale and color Doppler is the most helpful imaging modality to differentiate normal thyroid parenchyma from diffuse or nodular thyroid disease by evaluating glandular size, echogenicity, echotexture, margins, and vascularity. The various causes of diffuse thyroid disease often have overlapping sonographic imaging features. Thyroid nodules may be hyperplastic or neoplastic, with most due to benign hyperplastic changes in architecture and benign follicular adenomas; only a small percentage are malignant. A systematic approach to nodule morphology that includes evaluation of composition, echogenicity, margin, shape, and any echogenic foci can guide decision to biopsy or follow nodules.

Purpose The aim of this study was to systematically improve ultrasound image quality via the implementation of a quality control (QC) sonographer. Methods The position of a QC sonographer was created, whose responsibility was to preview ultrasound examinations performed by other sonographers and audit ultrasound examinations for image quality and protocol adherence. Retrospective audits of examinations performed before and after the implementation of the QC sonographer position were performed. Examinations from 17 sonographers were audited (16 examinations per sonographer), with a sample size of 272 examinations per audit. The QC sonographer graded the following imaging quality parameters (IQPs) as acceptable or needing improvement: gain, depth, color Doppler, spectral Doppler, and protocol adherence. Statistical comparisons were performed by a biostatistician using a χ2 test, with P Results The baseline audit (September 1, 2015 to November 30, 2015) revealed 439 instances of IQPs that required improvement. A second audit after establishing the QC sonographer role (August 1, 2016 to October 31, 2016) found 176 instances of IQPs that required improvement. A third, follow-up audit (May 1, 2018 to September 30, 2018) found 172 instances of IQPs that required improvement. Conclusions Removing a sonographer from the clinical line to work as a QC sonographer resulted in a 60% decrease in parameter errors that was maintained over time. Another benefit of the QC sonographer role is improved sonographer education.

Leiomyomas are the most common neoplasm found in the uterus and can present with a variety of symptoms or be entirely asymptomatic. Most often, the characteristic imaging appearance of leiomyoma does not pose a diagnostic dilemma. However, leiomyomas can demonstrate atypical imaging features that may be confusing. It is essential for the radiologist to be aware of both the typical and atypical findings to better assist the referring clinician with diagnosis and management decisions. Additionally, as uterine-sparing treatment alternatives with locoregional therapies become more popular, it is important to be aware of pre- and post-procedural imaging questions that may be encountered. Lastly, when atypical features are seen, it is important to understand the characteristics that may suggest a diagnosis of leiomyosarcoma. The goal of this study is to review imaging features of atypical leiomyoma with case-based examples.

Objective: Diagnostic work-up of suspicious renal masses has traditionally been conducted with contrast-enhanced computed tomography (CECT) and/or magnetic resonance imaging (MRI). However,...

Although common nonspecific symptoms (i.e., rectal bleeding, pelvic pressure, and change in bowel habits) are associated with rectal cancer, occasionally these are related to a different underlying disease. Over the past few years, considerable progress has been made in imaging of the rectum. Specifically, new magnetic resonance techniques and capabilities provide impressive high-resolution assessment of the rectal wall and enable evaluation and characterization of the perirectal tissues. This paper reviews imaging findings of uncommon causes of rectal and perirectal pathology that may be clinically confounded with rectal cancer. Radiologists need to be aware of uncommon pathologies in this region in order to facilitate optimal management decisions.

OBJECTIVE. Nonresectoscopic endometrial ablation techniques are being used as an alternative first-line management for menorrhagia. With these techniques, patients are at risk of developing delayed complications including painful obstructed menses, such as central hematometra and cornual hematometra, and postablation tubal sterilization syndrome. Pregnancy and the detection of endometrial cancer after ablation pose challenges in management. CONCLUSION. Radiologists should recognize the normal imaging findings in patients who have undergone endometrial ablation, be aware of the causes of treatment failure, and accurately identify delayed complications associated with these procedures.

There are many considerations in the evaluation of liver malignancy before planned surgical treatment. This article focuses on interpretation of MR imaging of the liver for surgical treatment planning of hepatocellular carcinoma, colorectal cancer metastases, and hilar cholangiocarcinoma. Clinical status, anatomic variants, future liver remnant, and underlying liver disease are all important factors in the decision to proceed with liver resection. The primary objective of preoperative imaging is to correctly identify patients who are candidates for curative intervention and to accurately stage their disease. Treatment planning for these complex patients is best done with a multidisciplinary team approach.

The purpose of this pictorial review is to describe the normal appearance of the endometrium and to provide radiologists with an overview of endometrial pathology utilizing case examples. The normal appearance of the endometrium varies by age, menstrual phase, and hormonal status with differing degrees of acceptable endometrial thickness. Endometrial pathology most often manifests as either focal or diffuse endometrial thickening, and patients frequently present with abnormal vaginal bleeding. Endovaginal ultrasound (US) is the first-line modality for imaging the endometrium. This article will discuss the endometrial measurements used to direct management and workup of symptomatic patients and will discuss when additional imaging may be appropriate. Three-dimensional US is complementary to two-dimensional ultrasound and can be used as a problem-solving technique. Saline-infused sonohysterogram is a useful adjunct to delineate and detect focal intracavitary abnormalities, such as polyps and submucosal fibroids. Magnetic resonance imaging is the preferred imaging modality for staging endometrial cancer because it best depicts the depth of myometrial invasion and cervical stromal involvement. Unique imaging features and complications of endometrial ablation will be introduced. At the completion of this article, the reader will understand the spectrum of normal endometrial findings and will understand the workup of common endometrial pathology.

Extra-adrenal paragangliomas of the urinary bladder are rare. Typically, patients present with symptoms related to catecholamine hypersecretion or mass effect, but these tumors can also be encountered incidentally on imaging studies obtained for a different purpose. It is important to recognize the key imaging features of this entity so that it may be suggested as a possible differential diagnosis in the setting of a newly identified bladder mass.

There are many considerations in the evaluation of liver malignancy before planned surgical treatment. This article focuses on interpretation of MR imaging of the liver for surgical treatment planning of hepatocellular carcinoma, colorectal cancer metastases, and hilar cholangiocarcinoma. Clinical status, anatomic variants, future liver remnant, and underlying liver disease are all important factors in the decision to proceed with liver resection. The primary objective of preoperative imaging is to correctly identify patients who are candidates for curative intervention and to accurately stage their disease. Treatment planning for these complex patients is best done with a multidisciplinary team approach.

OBJECTIVE. This article reviews the range of adnexal masses that present in pediatric females. The preferred imaging modalities, the appearance of the normal ovaries, and the epidemiology of ovarian diseases and abnormalities are discussed. The illustrated abnormalities include simple and complex ovarian and paraovarian cysts, neoplasms, ovarian torsion, ectopic pregnancy, and tuboovarian abscess, with attention to the imaging features and vascular flow patterns that help distinguish surgical from nonsurgical cases, malignant from benign lesions, and ovarian abnormalities from mimickers. CONCLUSION. The critical clinical questions to the radiologist in the setting of adnexal lesions are the site of origin, benign versus malignant features, and presence of infection or abscess. Pairing clinical presentation and imaging findings will direct appropriate management, whether it is reassurance, follow-up imaging, or surgery.