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.

Superior Mesenteric Artery Thrombosis and Intestinal Ischemia as a Consequence of COVID-19 Infection.

COVID-19-associated arterial and venous thrombotic events are multifactorial in origin, resulting in significant morbidity and mortality. Intestinal ischemia due to thrombus is a rare manifestation of COVID infection. Here, we report the case of a patient who presented with fever, malaise, and diarrhea, and was found to be COVID-19 positive; his clinical course was further complicated by devastating thrombosis of the superior mesentery artery (SMA) associated with COVID-19 infection.

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.

Management and Outcome of Heparin-Induced Thrombocytopenia in Pregnancy: A Systematic Review.

OBJECTIVE: Safety and efficacy of therapeutic agents used for heparin-induced thrombocytopenia are not established in pregnancy. METHODS: MEDLINE database was searched in November 2014 to identify all patients who received therapy for HIT during pregnancy. RESULTS: A total of 12 patients with the median age of 28 years (range 21-39) were diagnosed with HIT at the median gestational age of 20 weeks (range 5-34). Clinical probability (4T) score for HIT was high (50%) or intermediate (50%) and associated with thrombosis in 50%. Patients were initially managed with lepirudin (33%), argatroban (25%), danaparoid (25%) or fondaparinux (17%) and ultimately bridged to vitamin K antagonist or maintained on lepirudin. All patients had resolution of HIT. Complications included therapeutic abortion prior to valve replacement for valve thrombosis (8%), preterm delivery (18%) and preeclampsia (8%). Except for one instance of hypoplastic lung related to preterm delivery, none of the other newborns had any complications during delivery. CONCLUSION: Confirmed cases of HIT in pregnant patients appear to be rare. Within the limits of retrospective analysis, the use of argatroban, danaparoid, fondaparinux and lepirudin may be effective in preventing the thrombotic complications of HIT in pregnancy. The effect of HIT or its therapy on obstetrical complications cannot be determined based on this study since many of the obstetrical complications are common in otherwise healthy pregnancies. Although this study did not identify any fetal teratogenicity except hypoplastic lung related to preterm delivery, small number of cases treated with various therapies precludes any definite conclusion.

Emerging therapy options in heparin-induced thrombocytopenia.

Heparin-induced thrombocytopenia (HIT) is a life and limb-threatening thrombotic complication of heparin, which is the result of platelet activation by anti-PF4/heparin antibodies. With lepirudin and danaparoid no longer available in the US, treatment options are limited to argatroban, fondaparinux (off-label use) and bivalirudin (for patients undergoing percutaneous coronary intervention). Both argatroban and bivalirudin are parenteral drugs and require close monitoring and hospitalization. Fondaparinux is contraindicated in patients with significant renal impairment and is associated with a small risk of HIT. Anticoagulants approved for thromboprophylaxis and management of thromboembolic conditions such as rivaroxaban, dabigatran, and apixaban have fixed oral dose, rapid onset of action and does not require monitoring. These novel agents do not interact with anti-PF4/heparin antibody and offer attractive therapy options for HIT. Their utility in HIT has been supported by a few clinical reports, however, larger studies are needed before they can be utilized in clinical practice. Therapeutic plasma exchange has been utilized with some success in patients with HIT, who need heparin reexposure for cardiac surgery but their safety and efficacy needs further exploration. 2-O, 3-O desulfated heparin, which lacks any anticoagulant effect, has been shown to reduce the development of HIT in murine models. Finally, novel targets based on the molecular pathogenesis of HIT are being studied for therapeutic drug development. We hope that the availability of novel therapies in the future will expand the options available for the management of HIT.