Single-source dual-energy CT angiography with reduced iodine load in patients referred for aortoiliofemoral evaluation before transcatheter aortic valve implantation: impact on image quality and radiation dose.

OBJECTIVES: To compare image quality and radiation dose of pre-transcatheter aortic valve implantation (TAVI) aortoiliofemoral CT angiography (AICTA) provided by standard vs. dual-energy mode with reduced iodine load protocols. METHODS: One hundred and sixty-one patients underwent a two-step CTA protocol before TAVI including cardiac CTA with injection of 65 mL of iodinated contrast agent (ICA), immediately followed by AICTA. From this second acquisition, the following three different patient groups were identified: Group 1: 52 patients with standard AICTA (60 mL ICA, 100 kVp, mA automodulation); Group 2: 48 patients with dual-energy AICTA with 50 % iodine load reduction (30 mL ICA, fast kVp switching, 600 mA); Group 3: 61 patients with an identical protocol to Group 2, but exposed to 375 mA. The qualitative/subjective image quality (13-point score) and quantitative/objective image quality (contrast attenuation and image noise) were evaluated. The radiation dose was recorded. RESULTS: There was no significant difference in non-diagnostic images between the three protocols. Contrast attenuation, signal-to-noise ratio and contrast-to-noise ratio were significantly higher, whereas noise was significantly lower in the standard protocol (all P < 0.05). The radiation dose was lower in the dual-energy protocol at 375 mA (P < 0.05). CONCLUSIONS: Dual-energy AICTA before TAVI results in a reduction of iodine load while maintaining sufficient diagnostic information despite increased noise. KEY POINTS: • Dual-energy AICTA before TAVI results in a 50 % reduction of iodine load. •The reduction of iodine load maintains sufficient image quality despite increased noise. • Using 375 mA in dual-energy mode results in a reduction of radiation dose. • A high tube current setting (600 mA) should be used in overweight patients.

64-Slice CT angiography of the abdominal aorta and abdominal arteries: comparison of the diagnostic efficacy of iobitridol 350 mgI/ml versus iomeprol 400 mgI/ml in a prospective, randomised, double-blind multi-centre trial.

PURPOSE: The purpose of this study was to assess the influence of iodine concentration on diagnostic efficacy in multi-detector-row computed tomography (MDCT) angiography of the abdominal aorta and abdominal arteries. METHODS: IRB approval and informed consent were obtained. In this double-blind trial, patients were randomised to undergo MDCT angiography of the abdominal arteries during administration of iobitridol (350 mgI/ml) or iomeprol (400 mgI/ml). Each centre applied its own technique for delivery of contrast medium, regardless of iodine concentration. Diagnostic efficacy, image quality, visualisation of the arterial wall and arterial enhancement were evaluated. A total of 153 patients received iobitridol and 154 received iomeprol. RESULTS: The ability to reach a diagnosis was "satisfactory" to "totally satisfactory" in 152 (99.3%) and 153 (99.4%) patients respectively. Image quality was rated as being "good" to "excellent" in 94.7 and 94.8% segments respectively. Similar results were observed for image quality of arterial walls (84.3 vs. 83.2%). The mean relative changes in arterial enhancement between baseline and arterial phase images showed no statistically significant differences. CONCLUSION: This study demonstrated the non-inferiority of the 350 versus 400 mgI/ml iodine concentration, in terms of diagnostic efficacy, in abdominal MDCT angiography. It also confirmed the high robustness and reliability of this technique across multi-national practices.

Late supra-diaphragmatic lymph node recurrence following resection of a fibrolamellar hepatocarcinoma: an unusual case.

We report the case of a patient who presented with a supra-diaphragmatic lymph node recurrence 8 years after resection of a right liver fibrolamellar carcinoma. Treatment of this recurrence consisted of local excision by a right thoracotomy approach. Postoperative course was uneventful and the patient did not experience recurrence within 2 years. Based on this observation, we describe the major lymphatic vessels of the liver, in order to explain this unusual metastatic site occurrence.