Current update on the role of endoanal ultrasound: a primer for radiologists.

Endoanal ultrasound (EAUS) is a valuable imaging modality for the evaluation of anal and perianal pathologies. It provides detailed information about the anatomy and physiology of the anorectal region and has been used in pre-and post-operative settings of anorectal pathologies. EAUS is not only useful in the evaluation of benign pathologies but also in loco-regional staging of anal and rectal tumors. EAUS has several advantages over MRI, including reduced cost, better patient tolerance, and improved scope of application in patients with contraindications to MRI. Despite its benefits, EAUS is not widely performed in many centers across the globe. This article aims to educate radiologists, trainees, and surgeons about the indications, contraindications, patient preparation, imaging technique, and findings of EAUS. We will also highlight the technical difficulties, diagnostic challenges, and procedural complications encountered during EAUS, along with a comparative analysis of EAUS with other imaging approaches.

Imaging of inferior vena cava normal variants, anomalies and pathologies, Part 2: Acquired.

The inferior vena cava (IVC) is an uncommon site for primary pathologies and secondary involvement is also infrequent, but involvement of the IVC can often drastically change management. It is therefore important to be cognizant of IVC pathologies. This review discussed common and rare neoplastic and non-neoplastic pathologies of the IVC as well as pathology mimics. Primary and secondary neoplasms can lead to tumour extension or bland thrombus formation and it is often important to distinguish between these two entities. It is also important to be aware of pseudo-lesions for accurate diagnosis. Inferior vena cava filter placement and endovascular treatment of the aorta are commonly performed procedures that can be associated with devastating complications, which are luckily infrequent. The calibre of the IVC also has its own clinical significance. Inferior vena cava pathologies, although rare, have a dramatic impact on the patient's outcome and knowledge of these pathologies is prudent. Contribution: Understand the principles of IVC imaging, the common as well as the rare primary and secondary IVC tumours, differentiate between tumour thrombus and bland thrombus, and recognise IVC lesion mimics and life-threatening pathologies involving the IVC.

Imaging of inferior vena cava normal variants, anomalies and pathologies, Part 1: Congenital.

The embryology of the inferior vena cava (IVC) is complex, involving the sequential appearance and regression of multiple segments that ultimately form the IVC. Any alteration in this process during embryogenesis can result in congenital anomalies of the IVC. This study aimed to recognise common as well as rare anomalies of the IVC and associated veins, and their clinical implications. The anomalies tend to have diverse appearances based on the timing and segments involved. The development of the IVC is intertwined with the development of other veins like the renal vein, azygos vein and portal vein, and these veins may also be anomalous. Additionally, IVC anomalies are associated with various other congenital anomalies including cardiac anomalies, the recognition of which may be important for patient care. The IVC tends to have multiple normal variants and anomalies because of a complex process involving multiple segments contributing to the adult IVC. Knowledge of these variants is crucial for preoperative planning of procedures. Contribution: This study would help in understanding the embryogenesis of the IVC and correlation with the imaging appearances and the clinical implications of each of these common as well as rare types of congenital anomalies.

CT guided injection of 99mTc-MAA for lung nodule localization prior to VATS.

AIM: CT guided technetium99m-macroaggregated albumin (99mTc-MAA) injection for lung nodule localization prior to video-assisted thoracoscopic surgery (VATS) is employed at our institution for more than a decade. We retrospectively studied the success rate, factors that affect outcomes, and complications of this procedure. MATERIALS AND METHODS: 147 patients with 164 nodules underwent this procedure before VATS. Imaging and procedure characteristics, complications of the procedure, successful intra-operative localization and wedge resection, if there was conversion of primary VATS to open thoracotomy and if so the reason, and histopathological diagnosis for each nodule were reviewed by two radiologists in consensus. In case of unsuccessful wedge resection, reasons for failure were derived from electronic medical record. The impact of nodule and procedure characteristics on successful intra-operative localization was assessed. RESULTS: Excluding 9 nodules with unsuccessful localization due to non-procedure related reasons, the CT guided procedure was successful in 96.1% for intraoperative localization (149/155). Pleural leak of the radiotracer, split injection within the lobe, injection into a wrong nodule and gamma probe malfunction were primary reasons for failure. Nodule size, depth from pleura, and time between radiotracer injection and surgical incision did not impact success of the procedure. Among the 6 cases with procedure related failure, only 1 required conversion to open thoracotomy. CONCLUSION: CT guided 99mTc-MAA injection for intra-operative lung nodule localization is a feasible procedure with a high success rate and low complication rate. Attention to technique can potentially avoid procedure failure.

Twists and turns in acute abdomen: imaging spectrum of torsions and volvulus.

Twisting of the abdominal organs usually leads to acute abdomen, and a timely diagnosis is critical to salvage organ viability. Early diagnosis and prompt intervention are essential to avoid complications of ischemia and gangrene. Volvulus/torsion of the abdominal and pelvic organs present with non-specific clinical symptoms such as acute severe abdominal or pelvic pain generally necessitating imaging diagnosis. Since the timely critical diagnosis is necessary, emergency radiologists need to be well versed with the pertinent imaging findings of this acute surgical condition.

Current update on status of saline infusion sonohysterosalpingography.

The purpose of this article is to elucidate the current role of saline infusion sonohysterosalpingography (SIS) in evaluation of various uterine pathologies. SIS improves visualization of the endometrium and pathologies related to endometrial cavity, as well as it can simultaneously assess tubal patency. SIS provides high-resolution images, and three-dimensional (3D) reformatted images provide excellent orientation for radiologists as well as the clinicians about the underlying pathologies. This article will discuss imaging technique, indications, pearls, and pitfalls in imaging, diverse disease pathologies, and ultimately compare performance of SIS among other different imaging modalities. SIS as an adjunct imaging modality results in a greater diagnostic yield for diverse uterine pathologies.

Problem-solving with MRI in acute abdominopelvic conditions, part 1: gastrointestinal, hepatobiliary, and pancreatic diseases.

The purpose of this article is to review the benefit and added value and advantages of magnetic resonance imaging (MRI) compared with other cross-sectional imaging in patients presenting with abdominopelvic emergencies. During the past decade, there has been increased utilization of MRI in the emergency department with widespread availability of MR scanners, improvement in rapid imaging techniques, and methods to overcome motion-related artifacts. This has benefited patients at higher risk of radiation, particularly children and pregnant women, and patients with contraindications to iodinated contrast including allergy and renal dysfunction. Still the challenges are: on site MR scanner in the emergency department, after-hour services, as well as availability of time slot to rapidly scan emergency patient. MRI has additional advantages over other imaging modalities due to its high contrast resolution, which allows it to better characterize tissue and fluid collections, and may avoid the need for intravenous contrast. Radiologists must be familiar with the role and added value of MRI, spectrum of imaging findings, and problem-oriented modified MR protocols in abdominal and pelvic emergencies. In part 1, we will discuss the utility of MRI in gastrointestinal, hepatobiliary, and pancreatic diseases. In part 2, the authors will focus on the key MR imaging features of female pelvic gynecological diseases, pregnancy related complications, abdominal vascular complications, and renal diseases.

Imaging of ureter: a primer for the emergency radiologist.

In this review article, we will discuss the gamut of abnormalities involving the ureters. In the emergency department, ureterolithiasis is the most common indication for imaging abdomen and pelvis. However, spectrum of ureteral abnormalities including congenital, infectious and inflammatory, primary and secondary ureteral malignancies, retroperitoneal fibrosis rare described in this article may be encountered. Thus, we will describe acute subacute as well as chronic conditions that may affect ureter. Knowledge of common, as well as rare entities and their imaging features, is of utmost importance to enable appropriate management.

Rare presentation of chronic recurrent multifocal osteomyelitis of the Iliac wing mimicking Ewing's sarcoma.

This report describes a case of chronic recurrent multifocal osteomyelitis (CRMO) in an 11-year-old girl, involving the iliac bone as an initial, solitary site. Atypical imaging features were suspicious of a bone tumour, such as Ewing's sarcoma. Chronic recurrent multifocal osteomyelitis is a great masquerader and can present atypically. Radiologists should be familiar with both typical and atypical presentations, to determine an accurate diagnosis and guide appropriate management. Timely diagnosis may avoid invasive bone biopsy and inappropriate long-term antibiotic prescription for children.

Pancreatic cystic neoplasms: a review of current recommendations for surveillance and management.

Pancreatic cystic neoplasms (PCN) comprise of a diverse array of pancreatic cysts, including intraductal papillary mucinous neoplasms (IPMN), mucinous cystic neoplasms (MCN), serous cystic neoplasms (SCN), cystic neuroendocrine tumors (cNET), and many others. Increasing use of cross-sectional imaging has resulted in greater numbers of PCNs discovered incidentally. The overall risk of malignancy is low, but can vary considerably between different classes of PCNs. Furthermore, many pancreatic cysts are indeterminate on imaging, and the inability to reliably predict the course of disease remains a challenge for radiologists. Due to the variability in disease course and a lack of high-quality studies on PCNs, there is no universal consensus when it comes to balancing optimal surveillance while avoiding the risk for overtreatment. Currently, there are three widely accepted international guidelines outlining guidelines for surveillance and management of PCNs: the American Gastroenterological Association (AGA) in 2015, the International Association of Pancreatology (IAP) last revised in 2017, and the European Study Group on Cystic Tumours of the Pancreas (European) last revised in 2018. In 2017, the American College of Radiology released its own comprehensive set of recommendations for managing indeterminate pancreatic cysts that are detected incidentally on CT or MRI. The purpose of this paper is to describe the key differences between the ACR recommendations and the aforementioned three sets of guidelines regarding cyst management, imaging surveillance, performance, and cost-effectiveness.

Papillary Urothelial Carcinoma of Urinary Bladder Identified on 18F-Fluciclovine PET/CT.

ABSTRACT: 18F-fluciclovine is a radiolabeled synthetic amino acid recently approved by the Food and Drug Administration for evaluating recurrent prostate cancer. Upregulated amino acid transporters in prostate cancer cells result in elevated radiotracer uptake in sites of tumor recurrence. However, 18F-fluciclovine is not specific for prostate cancer. Nonprostatic malignancies and benign conditions can also demonstrate uptake. This information combined with the knowledge about common patterns of prostate cancer recurrence helps guide appropriate management. We present an 87-year-old man with biochemical recurrence for prostate cancer but found to have a urinary bladder wall mass on 18F-fluciclovine PET/CT with moderate avidity. Biopsy revealed papillary urothelial carcinoma.

Gas Where It Shouldn't Be! Imaging Spectrum of Emphysematous Infections in the Abdomen and Pelvis.

OBJECTIVE. The purpose of this article is to review the spectrum, etiopathogenesis, clinical presentation, imaging features, differential diagnoses, and management of emphysematous infections of the abdomen and pelvis. CONCLUSION. Emphysematous infections are associated with high morbidity and mortality and thus need urgent medical and surgical interventions. CT is the most sensitive modality to detect gas; CT provides definitive diagnosis in most cases and can depict the extent of involvement.

"Perifollicular rim sign" in an enlarged ovary-an additional non-contrast CT finding in ovarian torsion.

PURPOSE: To look for the presence of "perifollicular rim sign" on non-contrast CT in surgically proven cases of ovarian or adnexal torsion. METHODS: A retrospective analysis of abdominopelvic non-contrast CT examinations in surgically proven cases of ovarian or adnexal torsion was conducted seeking the presence of "perifollicular rim sign" in torsed ovaries. "Perifollicular rim sign" was defined as a complete ring of perifollicular hyperdensity around ovarian follicles with an attenuation value of > 50 HU and thickness > 1-2 mm. A positive sign was equated to the presence of perifollicular hemorrhage. Pre-operative non-contrast CT was available in 7 out of the 39 ovarian or adnexal torsions included in our study. RESULTS: "Perifollicular rim sign" was present in 5 out of the 7 ovarian torsions on pre-operative non-contrast CT. MRI correlation was available in one patient. Ovarian enlargement (>4 cm) was present in all 7 cases. CONCLUSION: In an appropriate clinical setting, presence of "perifollicular rim sign" in an enlarged ovary on non-contrast CT examination can be considered a useful additional sign for ovarian torsion.

Imaging spectrum of common and rare infections affecting the lower genitourinary tract.

In this review, we will discuss the imaging findings of common as well as uncommon lower genitourinary tract infections. For both clinicians and radiologists, it is imperative to understand etiopathogenesis, epidemiological information, clinical presentation, imaging findings and management options of such conditions. Knowledge of salient imaging features of these infections is of utmost importance because prompt recognition enables appropriate management.

Utility of MRI in Management of a Rare Case of Unilateral Dichorionic-Diamniotic Twin Tubal Ectopic Pregnancy.

Twin tubal ectopic pregnancies are rare events but critical diagnoses to make in emergency settings. They are common in patients who received in vitro- fertilization and in those with history of PID. Unless 2 embryos are live with detectable heart beats, ultrasound cannot definitely diagnose twin tubal EP. In clinically stable patients, MRI may provide other concrete findings to establish the diagnosis and lead to better management. In literature, to best of our knowledge, there has been no reported case of twin tubal EP evaluated with MRI. In this article, we have briefly reviewed the role of MRI in different types of EP and its limitations. We report an interesting case of ruptured tubal twin EP diagnosed with MRI which was sub optimally evaluated with ultrasound.

Imaging of non-epithelial neoplasms of the prostate.

The purpose of this article is to review the spectrum of rare non-epithelial tumors of the prostate. This focused article will help the readers to understand the imaging findings of such rare entities attributed to their clinicopathological features. Radiologists must be familiar with the spectrum of non-epithelial tumors of the prostate, which helps to suggest alternate diagnosis other than adenocarcinoma, when imaging features are atypical. This is important because these tumors have different management approaches and prognoses when compared to adenocarcinoma of the prostate.

Agenesis of the piriformis muscle: A case report with review of literature.

Agenesis of the piriformis muscle is an extremely rare occurrence. Knowledge about this anatomic variant is important because of its close proximity with the sciatic nerve and sacral plexus. The piriformis muscle also serves as an important anatomic landmark for image-guided intervention and hip surgery. We report a case of piriformis muscle agenesis in a 28-year-old woman, incidentally detected on magnetic resonance imaging of the lumbosacral spine and pelvis, performed for low back pain.

Extraprostatic extension in prostate cancer: primer for radiologists.

The presence of extraprostatic extension (EPE) on multiparametric MRI (mpMRI) is an important factor in determining the management of prostate cancer. EPE is an established risk factor for biochemical recurrence of prostate cancer after radical prostatectomy (RP) and patients with EPE may be considered for wider resection margins, non-nerve-sparing surgery, adjuvant radiation therapy (RT), or androgen deprivation therapy (ADT). Several statistical nomograms and scoring systems have been developed to predict pathological stage at time of RP but with varying accuracies. Using the current PI-RADS v2 mpMRI staging guidelines results in high specificity but lacks in sensitivity. These findings reveal the need for more standardization and further refinement of existing MRI protocols and prostate cancer prediction tools. Current studies have looked into indirect additional imaging criteria such as index tumor volume, length of capsular contact, and apparent diffusion coefficient. Measuring for these features can improve the robustness of mpMRI in staging prostate cancer, as they have been shown to be independent predictors of EPE. MRI/ultrasound fusion-guided targeted biopsy can detect EPE not found on standard biopsy. Collectively, these measurements and imaging techniques can augment the detection of EPE and subsequent risk stratification.