Comparison of radiation dose and image quality between flat panel computed tomography and multidetector computed tomography in a hybrid CT-angiography suite.

The purpose of this study was to compare, using the same radiation dose and image quality metrics, flat panel computed tomography (FPCT) to multidetector CT (MDCT) in interventional radiology. A single robotic angiography system with FPCT was compared to a single MDCT system, both installed in a hybrid CT-angiography laboratory and both operating under automatic exposure control. Radiation dose was measured on the central axis (Dc ) of a CT dosimetry phantom 30 cm in diameter and 60 cm in length using default protocols for FPCT and MDCT with the imaged length in MDCT matched to the field of view of FPCT. The noise power spectrum (NPS), modulation transfer function (MTF), and z-axis resolution were measured using the same phantom. Iodine contrast to noise ratio (CNR) was also measured. Radiation dose (Dc ) was 41%-69% lower in MDCT compared to FPCT when default protocols and automatic exposure control were used. While spatial resolution could generally be matched with appropriate choice of kernel in MDCT, MTF dropped more quickly at higher spatial frequency for MDCT than FPCT. Image noise was 49%-120% higher for MDCT compared to FPCT for comparable in-plane spatial resolution. Z-axis resolution was slightly better for MDCT than FPCT, while iodine CNR depended on protocol selection. Radiation dose was much lower for MDCT compared to FPCT, but image noise was much higher. Matching image noise in MDCT to FPCT would result in similar radiation doses. Iodine contrast depended on dose modulation settings for MDCT

Minimally invasive image-guided therapies for hepatocellular carcinoma

Mohamed E Abdelsalam,1 Ravi Murthy,1 Rony Avritscher,1 Armeen Mahvash,1 Michael J Wallace,1 Ahmed O Kaseb,2 Bruno C Odisio,1 1Department of Interventional Radiology, 2Department of Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA Abstract: Hepatocellular carcinoma (HCC) is the fifth most frequently occurring cancer globally and predominantly develops in the setting of various grades of underlying chronic liver disease, which affects management decisions. Image-guided percutaneous ablative or transarterial therapies have acquired wide acceptance in HCC management as a single treatment modality or combined with other treatment options in patients who are not amenable for surgery. Recently, such treatment modalities have also been used for bridging or downsizing before definitive treatment (ie, surgical resection or liver transplantation). This review focuses on the use of minimally invasive image-guided locoregional therapies for HCC. Additionally, it highlights recent advancements in imaging and catheter technology, embolic materials, chemotherapeutic agents, and delivery techniques; all lead to improved patient outcomes, thereby increasing the interest in these invasive techniques. Keywords: hepatocelleular carcinoma, locoregional therapy, TACE, ablation, 90

Improving CT-guided transthoracic biopsy of mediastinal lesions by diffusion-weighted magnetic resonance imaging

OBJECTIVES: To evaluate the preliminary results obtained using diffusion-weighted magnetic resonance imaging and the apparent diffusion coefficient for planning computed tomography-guided biopsies of selected mediastinal lesions. METHODS: Eight patients with mediastinal lesions suspicious for malignancy were referred for computed tomography-guided biopsy. Diffusion-weighted magnetic resonance imaging and apparent diffusion coefficient measurement were performed to assist in biopsy planning with diffusion/computed tomography fused images. We selected mediastinal lesions that could provide discordant diagnoses depending on the biopsy site, including large heterogeneous masses, lesions associated with lung atelectasis or consolidation, lesions involving large mediastinal vessels and lesions for which the results of biopsy using other methods and histopathological examination were divergent from the clinical and radiological suspicion. RESULTS: In all cases, the biopsy needle was successfully directed to areas of higher signal intensity on diffusion-weighted sequences and the lowest apparent diffusion coefficient within the lesion (mean, 0.8 [range, 0.6-1.1]×10-3 mm2/s), suggesting high cellularity. All biopsies provided adequate material for specific histopathological diagnoses of four lymphomas, two sarcomas and two thymomas. CONCLUSION: Functional imaging tools, such as diffusion-weighted imaging and the apparent diffusion coefficient, are promising for implementation in noninvasive and imaging-guided procedures. However, additional studies are needed to confirm that mediastinal biopsy can be improved with these techniques

Yttrium-90 resin microspheres as an adjunct to sorafenib in patients with unresectable hepatocellular carcinoma

Armeen Mahvash,1 Ravi Murthy,1 Bruno C Odisio,1 Kanwal Pratap Raghav,2 Lauren Girard,2 Sheree Cheung,1 Van Nguyen,3 Joe Ensor,4 Sameer Gadani,5 Khaled M Elsayes,6 Reham Abdel-Wahab,1,7 Manal Hassan,1 Ahmed S Shalaby,1 James C Yao,1 Michael J Wallace,1 Ahmed O Kaseb2 1Department of Interventional Radiology, 2Department of Gastrointestinal Medical Oncology, 3Department of Pharmacy, 4Department of Statistics, The University of Texas MD Anderson Cancer Center, Houston, TX, 5Department of Radiology, Saint Louis University Hospital, St Louis, MO, 6Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA; 7Department of Clinical Oncology, Assiut University Hospital, Assiut, Egypt Purpose: The safety and efficacy of the combined use of sorafenib and yttrium-90 resin microspheres (Y90 RMS) to treat advanced hepatocellular carcinoma (HCC) is not well established. We determined the incidence of adverse events with this combination therapy in patients with advanced HCC at our institution and analyzed the treatment and survival outcomes. Materials and methods: We reviewed the records of 19 patients with Barcelona Clinic Liver Cancer class B or C HCC who underwent treatment with Y90 RMS (for 21 sessions) while receiving full or reduced doses of sorafenib between January 2008 and May 2010. Therapy response was evaluated using Response Evaluation Criteria in Solid Tumors. We evaluated median overall survival (OS) and progression-free survival (PFS) as well as hepatic and extrahepatic disease PFS and incidence of adverse events. Results: The median patient age was 67 years, and portal or hepatic venous invasion was present in eight patients (42%). Ten patients received reduced doses of sorafenib. The median Y90 radiation activity delivered was 41.2 mCi. The partial response of Response Evaluation Criteria in Solid Tumors was observed in four patients (19%). The median hepatic disease PFS was 7.82 months, extrahepatic disease PFS was 8.94 months, OS was 19.52 months, and PFS was 6.63 months. Ninety days after treatment with Y90 RMS, five patients (26%) had grade II adverse events and four patients (21%) had grade III adverse events. Conclusion: OS and PFS outcomes were superior to those observed in prior studies evaluating sorafenib alone in patients with a similar disease status, warranting further study of this treatment combination. Keywords: yttrium-90, sorafenib, hepatocellular carcinom