Feasibility of Ultra-Low Volume Contrast-Saline Mixture Injection With Dual-Flow Technique in a Pre-TAVI Computed Tomography Angiography.

BACKGROUND: To explore the feasibility and image quality of ultra-low volume contrast-saline mixture injection with dual-flow injection technique in a computed tomography angiography (CTA) protocol in patients scheduled for transcatheter aortic valve implantation (TAVI). METHODS: Forty (40) TAVI candidates underwent investigation with CTA using a third-generation dual-source CT scanner between September and November 2020. Different volumes of a monophasic contrast-saline mixture at an 80:20 ratio were administered at an infusion rate of 3 mL/s in 20 patients (group A). The injected volume was based on patient body mass index (BMI): 50 mL if BMI <29 kg/m2 and 63 mL if BMI >29 kg/m2. The other 20 patients (group B)-the control cases-received a total of 65 mL of contrast medium (CM), in multiphasic injections at different flow rates, followed by 10 mL of saline. The images that were obtained were prospectively evaluated for image quality, vessel attenuation (HU), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and estimated radiation dose. RESULTS: Image quality of the aortic root and ilio-femoral vessels was diagnostic in all patients. Vascular attenuation was >200 HU and CNR >3 at any vessel level. CONCLUSIONS: Data from this study suggest that a monophasic ultra-low volume contrast-saline mixture injection with a dual-flow technique can provide clear visualisation of the aortic root and ilio-femoral vessels in pre-TAVI CTA, which is comparable with a standard multiphasic volume injection protocol.

Percutaneous Trans-Hepatic Embolization of an Iatrogenic Extra-Hepatic Pseudoaneurysm of the Right Hepatic Artery in a Patient With Previous Occlusion of the Proper Hepatic Artery: An Endovascular Procedure to Avoid a Difficult Surgical Repair.

We report a case of successful percutaneous transhepatic, embolization of an iatrogenic extra-hepatic pseudoaneurysm (PsA) of the right hepatic artery (RHA) under combined fluoroscopic and ultrasonographic guidance. A 73-year-old man underwent percutaneous transhepatic biliary drainage placement in another hospital, complicated by haemobilia and development of a RHA PsA. Endovascular embolization was attempted, resulting in coil embolization of the proper hepatic artery, and persistence of the PsA. At this point, the patient was referred to our hospital. Computed tomography and direct angiography confirmed the iatrogenic extra-hepatic PsA of the RHA, refilled by small collaterals from the accessory left hepatic artery (LHA) and coil occlusion of the proper hepatic artery. Attempted selective catheterization of these vessels was unsuccessful due to the tortuosity and very small caliber of the intra-hepatic collaterals, the latter precluding endovascular treatment of the PsA. Percutaneous trans-hepatic combined fluoroscopic and ultrasound-guided embolization of the PsA was performed with Lipiodol® and cyanoacrylate-based glue (Glubran®2). Real time fluoroscopic images and computed tomography confirmed complete occlusion of the pseudoaneurysm. Surgical repair, although feasible, was considered at high risk. In our patient, we decided to perform a percutaneous trans-hepatic combined fluoroscopic and ultrasound-guided embolization of the PsA using a mix of Lipiodol® and Glubran®2 because of the fast polymerization time of the glue allowing the complete occlusion of the PsA in few seconds, thus eliminating the risk of coil migration, reducing the risk of PsA rupture and avoid a difficult surgical repair.

Feasibility of combined ECG-Gated and Helical acquisition mode in a pre-TAVI computed tomography angiography protocol using a fixed low-volume contrast medium injection.

BACKGROUND: To investigate the feasibility, image quality, and clinical implications of a combined ECG-gated and helical acquisition mode in a computed tomography angiography (CTA) protocol in patients scheduled for transcatheter aortic valve implantation (TAVI) using a fixed, low-volume, contrast medium injection. METHODS: Between July and October 2019, 43 TAVI candidates underwent investigation with CTA using a 64-slice CT scanner. Images obtained were prospectively evaluated. 65 mL of low iodine dose contrast medium (CM), followed by 25 mL of saline, were administered using a fixed multiphasic injection protocol in all patients. Patients were divided into three groups based on BMI: Group 1 (n = 9) with BMI < 22 kg/m2; Group 2 (n = 22) with BMI 22-29 kg/m2; Group 3 (n = 12) with BMI > 29 kg/m2. Images were evaluated for image quality, vessel attenuation (HU), Signal-to-Noise Ratio (SNR), Contrast-to-Noise Ratio (CNR) and estimated radiation dose. Image quality of the aortic root and iliac-femoral vessels was diagnostic in all patients. RESULTS: Vascular attenuation was > 200 HU and CNR > 3 at all vessel levels. CONCLUSION: Data from our study suggest that it is possible to image the aortic annulus and aorto-iliac anatomy and obtain high image quality in all patients by using a combined ECG-gated and helical acquisition mode in a computed tomography angiography (CTA) protocol with a fixed low-volume contrast medium injection (65 mL). This allows for accurate CT measurements of the aortic annulus, recruitment of patients for TAVI and facilitates pre-procedural planning in these high surgical risk patients.