Imaging of Renal Transplant Complications throughout the Life of the Allograft: Comprehensive Multimodality Review.

The kidney is the most commonly transplanted solid organ. Advances in surgical techniques, immunosuppression regimens, surveillance imaging, and histopathologic diagnosis of rejection have allowed prolonged graft survival times. However, the demand for kidneys continues to outgrow the available supply, and there are efforts to increase use of donor kidneys with moderate- or high-risk profiles. This highlights the importance of evaluating the renal transplant patient in the context of both donor and recipient risk factors. Radiologists play an integral role within the multidisciplinary team in care of the transplant patient at every stage of the transplant process. In the immediate postoperative period, duplex US is the modality of choice for evaluating the renal allograft. It is useful for establishing a baseline examination for comparison at future surveillance imaging. In the setting of allograft dysfunction, advanced imaging techniques including MRI or contrast-enhanced US may be useful for providing a more specific diagnosis and excluding nonrejection causes of renal dysfunction. When a pathologic diagnosis is deemed necessary to guide therapy, US-guided biopsy is a relatively low-risk, safe procedure. The range of complications of renal transplantation can be organized temporally in relation to the time since surgery and/or according to disease categories, including immunologic (rejection), surgical or iatrogenic, vascular, urinary, infectious, and neoplastic complications. The unique heterotopic location of the renal allograft in the iliac fossa predisposes it to a specific set of complications. As imaging features of infection or malignancy may be nonspecific, awareness of the patient's risk profile and time since transplantation can be used to assign the probability of a certain diagnosis and thus guide more specific diagnostic workup. It is critical to understand variations in vascular anatomy, surgical technique, and independent donor and recipient risk factors to make an accurate diagnosis and initiate appropriate treatment.©RSNA, 2019.

Incidental Findings on Bedside Ultrasonography: Detection Rate and Accuracy of Resident-Performed Examinations in the Acute Setting.

BACKGROUND: Bedside ultrasonography has become a valuable tool in the emergent care setting for triage and rapid evaluation of patients who are acutely ill. Given the cross-sectional nature of ultrasound technology, incidental findings are frequently encountered during imaging. These can impact clinical management and can pose a diagnostic dilemma for emergency medicine (EM) physicians and EM residents. PURPOSE: Our retrospective study was designed to evaluate the prevalence and detection rate of incidental findings on bedside ultrasound examinations performed by EM residents. We also sought to identify types of incidental findings encountered and the diagnostic accuracy of those findings. MATERIALS AND METHODS: Board-certified radiologists retrospectively reviewed bedside ultrasonography examinations performed and interpreted by EM residents at a large urban academic hospital. Our sample included patients who presented with traumatic and nontraumatic symptoms in the acute setting. Findings were defined as incidental only if they were previously unknown and not related to a patients presenting symptoms. The results were corroborated with electronic medical records and additional pertinent imaging when available. RESULTS: Of 196 examinations analysed, EM residents identified incidental findings on 26% of the studies, which mostly involved the renal and biliary system. Radiologist review detected incidental findings in 20.9% but was more accurate when supplemental imaging was available. EM residents detected incidental findings at rates similar to that published previously and had moderate interobserver agreement with radiologist review. Worrisome and indeterminate findings were confirmed by additional work-up and further imaging. CONCLUSION: Incidental findings are frequently encountered on bedside ultrasonography and have the potential to alter clinical management. Expertise in detection and knowledge of the presence and spectrum of these incidental findings is essential for appropriate triage, patient management, and follow-up.

Colorectal emergencies and related complications: a comprehensive imaging review--noninfectious and noninflammatory emergencies of colon.

OBJECTIVE: In this article, we illustrate imaging findings of colorectal emergencies encountered in the acute setting that are primarily noninfectious and noninflammatory in origin. Our review should enable the reader to identify and understand common colorectal emergencies and related complications in clinical practice. CONCLUSION: The diagnosis of colorectal emergencies is mostly straightforward, but it can be challenging because of the overlap of presenting symptoms and imaging findings. Therefore, it is essential to clarify the cause, narrow the differential diagnosis, and identify associated complications.

Colorectal emergencies and related complications: a comprehensive imaging review--imaging of colitis and complications.

OBJECTIVE: Colorectal emergencies are a common presentation in the emergency medicine setting and their timely diagnosis plays a crucial role in avoiding dreaded complications. The quintessential role of a radiologist lies in identifying the cause, narrowing the differential diagnosis according to imaging features, and, most importantly, identifying the associated complications. CONCLUSION: This review focuses on imaging features of the spectrum of colitides and the complications related to colitides.

Nontraumatic acute aortic emergencies: Part 1, Acute aortic syndrome.

OBJECTIVE: The aim of this article is to illustrate the imaging findings and analyze the spectrum of findings seen in patients with acute aortic syndrome. We also will discuss the overlaps in pathophysiologic and imaging findings among aortic syndromes. CONCLUSION: Acute aortic syndrome includes acute aortic dissection, intramural hematoma, and penetrating atherosclerotic ulcer. The most common clinical presentation is severely painful and potentially life-threatening abnormalities of the aorta. Differentiating among these aortic diseases is impossible by symptoms or physical evaluation. Therefore, any clinical suspicion should prompt immediate action including confirmatory noninvasive imaging. Prognosis of acute aortic syndromes is clearly related to prompt diagnosis and appropriate management. Accurate imaging interpretation can modify the natural history of acute aortic syndrome and improve prognosis.

Nontraumatic acute aortic emergencies: Part 2, Pre- and postsurgical complications related to aortic aneurysm in the emergency clinical setting.

OBJECTIVE: The aim of this article is to illustrate the imaging findings and spectrum of disease entities affecting the aorta. The clinical presentation and assessment of acute aortic pathology can be elusive or deceptive, making the diagnosis challenging. The widespread availability of advanced cross-sectional imaging technology in the emergency setting puts the radiologist at the forefront of accurate and timely diagnosis. CONCLUSION: Cross-sectional imaging plays a pivotal role in the diagnosis and delineation of aortic pathology. Awareness of the imaging findings and complications can help in swift and accurate diagnosis.

Incidental findings detected on abdomino-pelvic multidetector computed tomography performed in the acute setting.

OBJECTIVE: The objective of the study is to determine the prevalence and significance of incidental findings in patients with a chief complaint of abdominal pain presenting to the emergency department (ED) who received abdomino-pelvic multidetector computed tomography. MATERIALS AND METHODS: We conducted a retrospective review of data collected for 290 patients over a period of 5 months (April to September 2012) from 3 different university-affiliated EDs. Two board-certified radiologists reviewed the original images independently and recorded the incidental findings. These findings were classified as benign, indeterminate, and worrisome. Only those findings present in the original report were included in the study. If an indeterminate or worrisome incidental finding was identified, the patient's medical records were reviewed to determine if the incidental finding was previously known, whether recommendation was made for further evaluation, and whether this recommendation led to any change in management. RESULTS: We identified 283 incidental findings­144 benign (51%), 114 indeterminate (40%), and 25 worrisome (9%) findings. A statistically significant difference was observed in the percentage of patients who experienced a change in management among those who received recommendations as compared with those who did not, in both previously known (87% vs 22%, P=.001) and previously unknown (70% vs 2%, P=.001) indeterminate findings. CONCLUSION: Unlike benign incidental findings, indeterminate and worrisome findings frequently alter the course of management. Recommendation from radiologists appears to significantly contribute to the management of indeterminate incidental findings.