Imaging Modalities Employed in the TAVR Procedure With a Focus on CTA: What the Radiologist Needs to Know.

RATIONALE AND OBJECTIVES: Aortic stenosis (AS) is one of the most common valvular heart disease. Symptomatic AS is associated with a high mortality rate which prompts fast intervention. The introduction of transcatheter aortic valve replacement (TAVR) has drastically improved the outcome of high surgical risk for mortality patients with severe AS. However, this procedure requires the employment of multimodality imaging in the pre-procedural planning, intra-procedural optimization, and post-procedural follow-up stages. This also requires an accurate understanding of the indications, measurements, strength, and limitations of each imaging modality during the different TAVR stages. CONCLUSION: In this review, we aim to outline to radiologists the evidence-based approach and indications of different imaging modalities through the pre, peri, and post TAVR stages.

Hepatic granuloma mimicking recurrent lymphoma on 18F-FDG PET/CT in a patient with primary mediastinal diffuse large B-cell lymphoma.

18F-Flurodeoxyglucose (FDG) PET/CT has been considered the modality of choice in detecting, staging, restaging and following-up with lymphoma patients. However, it has an uncertain role in differentiating hepatic lymphomatous relapse from other granulomatous diseases such as in candidiasis or sarcoidosis. Therefore, it is important to correlate the imaging findings with other modalities such as ultrasound, CT scan, MRI, and histology to direct the diagnosis and treatment. We present a case of a 33-year-old woman with large B-cell lymphoma in complete remission following treatment presenting with neutropenic fever following her final cycle of chemotherapy. Ultrasound of the abdomen and enhanced CT scan of the abdomen and pelvis were negative. The FDG PET/CT scan showed multiple FDG-avid hypodense hepatic lesions that were suggestive either of lymphoproliferative involvement or nonmalignant process. However, MRI of the abdomen performed four days later was suggestive of an infectious process, rather than a lymphoproliferative disorder. A subsequent CT-guided biopsy of a hepatic lesion showed granulomatous inflammation, with no evidence of malignancy or Tuberculosis. The patient was started on Caspofungin followed by Fluconazole. After 5 weeks, the clinical condition resolved, and the subsequent FDG PET/CT showed complete resolution of the FDG-avid multiple hepatic lesions.

Comparison Between Liver Stiffness Measurement by Fibroscan and Splenic Volume Index as NonInvasive Tools for the Early Detection of Oxaliplatin-induced Hepatotoxicity.

Background: Oxaliplatin remains an essential component of many chemotherapy protocols for gastrointestinal cancers; however, neurotoxicity and hepatotoxicity may be dose-limiting. The gold standard for the diagnosis of oxaliplatin-induced hepatotoxicity is liver biopsy, which is invasive and costly. Splenomegaly has also been used as a surrogate for liver biopsy in detecting oxaliplatin-induced sinusoidal obstruction syndrome (SOS), but splenic measurement is not routine and can be inaccurate and complex. We investigated the correlation between increased liver elasticity assessed by Fibroscan and the increase in spleen volume on cross-sectional imaging after oxaliplatin as a noninvasive technique to assess liver stiffness associated with oxaliplatin-induced SOS. Methods: Forty-six patients diagnosed with gastrointestinal cancers and planned to take oxaliplatin containing regimens were included in this prospective study at the American University of Beirut Medical Center (AUBMC). Measurement of spleen volume using cross-sectional imaging and of liver elasticity using Fibroscan was performed at baseline, 3 and 6 months after starting oxaliplatin. Mean liver elasticity measurements were compared between patients stratified by the development of splenomegaly using the Student t-test. Splenomegaly was defined as 50% increase in spleen size compared with baseline. Results: Patients who developed splenomegaly after oxaliplatin use had significantly higher mean elasticity measurements as reported by Fibroscan at 3 (16.2 vs. 7.8 kPa, P = 0.036) and 6 (9.3 vs. 6.7 kPa, P = 0.03) months. Conclusion: Measurement of elasticity using Fibroscan could be potentially used in the future as a noninvasive test for predicting oxaliplatin-induced hepatotoxicity.