Contrast-enhanced US in Renal Transplant Complications: Overview and Imaging Features.

Renal transplant is the first-line treatment of end-stage renal disease. The increasing number of transplants performed every year has led to a larger population of transplant patients. Complications may arise during the perioperative and postoperative periods, and imaging plays a key role in this scenario. Contrast-enhanced US (CEUS) is a safe tool that adds additional value to US. Contrast agents are usually administered intravenously, but urinary tract anatomy and complications such as stenosis or leak can be studied using intracavitary administration of contrast agents. Assessment of the graft and iliac vessels with CEUS is particularly helpful in identifying vascular and parenchymal complications, such as arterial or venous thrombosis and stenosis, acute tubular injury, or cortical necrosis, which can lead to graft loss. Furthermore, infectious and malignant graft involvement can be accurately studied with CEUS, which can help in detection of renal abscesses and in the differentiation between benign and malignant disease. CEUS is also useful in interventional procedures, helping to guide percutaneous aspiration of collections with better delimitation of the graft boundaries and to guide renal graft biopsies by avoiding avascular areas. Potential postprocedural vascular complications, such as pseudoaneurysm, arteriovenous fistula, or active bleeding, are identified with CEUS. In addition, newer quantification tools such as CEUS perfusion are promising, but further studies are needed to approve its use for clinical purposes. ©RSNA, 2024 Supplemental material is available for this article.

Replaced right hepatic artery arising from the distal renal artery, a new variation.

PURPOSE: Arterial irrigation of the liver is highly variable and widely studied due to its importance in the correct planification of the surgical or endovascular treatment of the hepatobilary area. Various classifications have been published of the common and uncommon anatomic variations of the hepatic arterial distribution. While the classic anatomic pattern of the proper hepatic artery-when it originates from the celiac trunk dividing into left and right branches-represents 50-83% of the described patterns, there are numerous uncommon distributions based on the presence of replaced or accessory hepatic arteries. In this article, we present a case of a replaced right hepatic artery originating from the right distal renal artery. METHODS: Contrast enhanced computed tomography (CECT) examination was performed on a 67 years-old male patient with compensated alcoholic cirrhosis as part of the disease monitoring. RESULTS: The replaced right hepatic artery of the patient arises from the right distal renal artery and-after its cranial course-enters the porta hepatis posterior to the main portal vein. After giving off the cystic artery, it irrigates the right hepatic lobe. The left hepatic artery does not show any variation. CONCLUSION: We present CT angiography images of an extremely rare anatomic variation of the hepatic arterial irrigation in a cirrhotic patient.

Liver Hydatid Cyst Rupture with Respiratory Distress During COVID-19 Pandemic.

We present a case of a young male patient who was brought to the emergency room with abdominal pain, fever, dyspnea and hypoxemia, and was initially oriented as an acute COVID-19 pneumonia. A thoracoabdominal computed tomography (CT) was performed to rule out pneumonia and the abdominal extension of the study revealed a hepatic hydatid cyst with rupture into the abdominal cavity with respiratory distress secondary to an anaphylactic reaction that, if left untreated, may lead to a fatal outcome. An urgent laparotomy was performed with cyst resection. The follow-up and complications are briefly described.

Susceptibility artifacts and PIRADS 3 lesions in prostatic MRI: how often is the dynamic contrast-enhance sequence necessary?

PURPOSE: To assess the need of the dynamic contrast-enhanced (DCE) sequence in addition to T2-weighted imaging (T2-WI) and diffusion-weighted imaging (DWI) for the detection of clinically significant prostate cancer in the presence of artifacts associated with rectal gas (which compromise the diffusion assessment) and/or PIRADS 3 lesions. METHODS: This retrospective study was approved by the institutional review board; informed consent was not required. Patients referred consecutively over a period of 5 months for elevated PSA underwent multiparametric magnetic resonance imaging (mpMRI). mpMRI was performed using a 3T MRI system without an endorectal coil. The MRI findings were reviewed by two radiologists and were scored according to the Prostate Imaging Reporting and Data System version 2.0 (PI-RADSv2). Any discrepancies were resolved by consensus. For statistical purposes, lesions were classified as PIRADS 1-2, PIRADS 3, or PIRADS 4-5. First, all studies were reviewed using a biparametric assessment (T2-WI + DWI), and the presence or absence of susceptibility artifacts was assessed for each prostate. Subsequently, all images were analyzed using the standard multiparametric approach (T2-WI + DWI + DCE). RESULTS: The biparametric evaluation (T2-WI + DWI) showed artifacts (due to the presence of rectal gas or other) in 87 patients (43.5%) and no artifacts in 113 patients (56.5%). In the latter group, 15 patients had peripheral zone (PZ) PIRADS 3 lesions. Thus, a total of 102 patients (51%) had artifacts or PZ PIRADS 3 lesions and therefore required DCE. When evaluating the group of prostates without artifacts, 13.3% of prostates required DCE. A total of 17 (23.9%) PIRADS 4-5 prostate lesions would have not been detected without the use of DCE. CONCLUSION: Biparametric evaluation of the prostate revealed some limitation due to the presence of artifacts or PIRADS 3 PZ lesions. Artifacts were present in almost 44% of our patients, but when the DWI was correctly evaluated, only 13.3% of prostates required DCE.

The role of contrast enhanced ultrasound in the differential diagnosis of segmental testicular infarction.

A 43-year-old male presented to the emergency department with acute left testicular pain. Physical exam showed a tender left testicle and epididymis with mild swelling. Doppler and contrast enhanced ultrasound revealed a heterogeneous, avascular lesion with hyper vascularized surrounding. Follow-up contrast enhanced ultrasound performed a few days later showed persistence of the sparsely vascularized lesion with more hypoechoic echo structure. Despite the tumor markers being negative, a necrotic tumor could not be ruled out and a left orchiectomy was performed. Pathology report described an extensive segmental testicular infarction with no evidence of malignant tissue. We present the ultrasound and pathology findings, differential diagnostic pearls and clinical perspective of segmental testicular infarction.

Persistent damage on magnetic resonance enterography in patients with Crohn's disease in endoscopic remission.

BACKGROUND: In Crohn's disease, it is essential to distinguish between persistent damage and abnormalities that can heal with anti-inflammatory therapy. AIM: To assess magnetic resonance enterography (MRE) lesions that persist in patients in long-standing endoscopic remission, analyse their relationship with baseline characteristics, and determine their prognostic implications. METHODS: We systematically reviewed pre- and post-treatment MRE findings in patients with Crohn's disease and severe inflammation (segmental CDEIS ≥ 7 or ulcers in at least one segment) who achieved endoscopic remission (CDEIS < 2) after 1 year of treatment with TNF-inhibitors or autologous haematopoietic stem-cell transplantation. Logistic regression analysis was used to identify predictors of persistent abnormalities. RESULTS: Endoscopic remission was achieved in 73 intestinal segments in 28 patients (69% females; 9.95 years disease duration, 67.9% inflammatory phenotype; 39.3% ileal location). Creeping fat and intestinal wall fat deposits were unchanged on pre- and post-treatment MRE despite the endoscopic remission. Luminal strictures persisted in 6 out of the 8 segments with baseline strictures, and wall thickening in 23 out of the 72 of segments with thickening at baseline. Predictors of persistent mural thickening were pre-treatment wall thickness > 5.9 mm (OR = 4.38, P = 0.027) and refractory disease prior to baseline (OR = 2.35, P = 0.001). Creeping fat was the only predictor for persistence of creeping fat (OR = 36.43, P < 0.001). Persistence of strictures at MRE is associated with earlier recurrence (P = 0.014). CONCLUSIONS: Persistent MRE abnormalities are frequent in patients with Crohn's disease despite achieving endoscopic remission. Significant wall thickening, intestinal fat deposition, strictures, and creeping fat at baseline MRE are signs of established damage.