Randolph M. Setser

Early experience with X-ray magnetic resonance fusion for low-flow vascular malformations in the pediatric interventional radiology suite

This technical innovation describes our experience using an X-ray magnetic resonance fusion (XMRF) software program to overlay 3-D MR images on real-time fluoroscopic images during sclerotherapy procedures for vascular malformations at a large pediatric institution. Five cases have been selected to illustrate the application and various clinical utilities of XMRF during sclerotherapy procedures as well as the technical limitations of this technique. The cases demonstrate how to use XMRF in the interventional suite to derive additional information to improve therapeutic confidence with regards to the extent of lesion filling and to guide clinical management in terms of intraprocedural interventional measures.

Metal artefact reduction algorithm for correction of bone biopsy needle artefact in paediatric C-arm CT images: a qualitative and quantitative assessment

Metal artefact reduction algorithm for correction of bone biopsy needle artefact in paediatric C-arm CT images: a qualitative and quantitative assessment S. Shellikeri *, E. Girard , R. Setser , J. Bao , A.M. Cahill a a The Children’s Hospital of Philadelphia, Department of Radiology, 34th and Civic Center Boulevard, Philadelphia, PA 10914, USA b Siemens Medical Solutions USA, Inc., Healthcare Technology Center, 755 College Road East, Princeton, NJ 08540, USA c Siemens Medical Solutions USA, Inc., Hoffman Estates, IL 60192, USA d Siemens Healthcare, Forchheim, Bayern 91301, Germany

Blood flow measurement using digital subtraction angiography for assessing hemodialysis access function

Blood flow rate is a critical parameter for diagnosing dialysis access function during fistulography where a flow rate of 600 ml/min in arteriovenous graft or 400-500 ml/min in arteriovenous fistula is considered the clinical threshold for fully functioning access. In this study, a flow rate computational model for calculating intra-access flow to evaluate dialysis access patency was developed and validated in an in vitro set up using digital subtraction angiography. Flow rates were computed by tracking the bolus through two regions of interest using cross correlation (XCOR) and mean arrival time (MAT) algorithms, and correlated versus an in-line transonic flow meter measurement. The mean difference (mean ± standard deviation) between XCOR and in-line flow measurements for in vitro setup at 3, 6, 7.5 and 10 frames/s was 118±63; 37±59; 31±31; and 46±57 ml/min respectively while for MAT method it was 86±56; 57±72; 35±85; and 19±129 ml/min respectively. The result of this investigation will be helpful for selecting candidate algorithms while blood flow computational tool is developed for clinical application.

Prospective evaluation of MR overlay on real-time fluoroscopy for percutaneous extremity biopsies of bone lesions visible on MRI but not on CT in children in the interventional radiology suite

Magnetic resonance imaging (MRI) often provides better visualization of bone marrow abnormalities than computed tomography (CT) or fluoroscopy, but bone biopsies are usually performed using conventional CT or, more recently, C-arm CT guidance. Biopsies of bone lesions solely visible on MRI are often challenging to localize and require the operator to review the MRI on a separate console to correlate with MRI anatomical landmarks during the biopsy. The MR overlay technique facilitates such biopsies in the angiographic suite by allowing the pre-procedural 3-D MRI to be overlaid on intraprocedural 2-D fluoroscopy. This study describes our initial experience with the MR overlay technique in the angiography suite during pediatric percutaneous extremity bone biopsies of lesions visible on MRI but not on CT or fluoroscopy and demonstrates its utility in relevant clinical cases.

Relationship between cone-beam CT technique and diagnostic usefulness in patients undergoing embolotherapy for hepatocellular carcinoma☆

AIM To determine the effect of different numbers of projection images in C-arm cone-beam computed tomography (CBCT) on diagnostic content and image quality in patients undergoing angiographic embolotherapy for hepatocellular carcinoma (HCC). MATERIALS AND METHODS A total of 29 patients who underwent contrast-enhanced conventional multidetector CT (MDCT) within 6 weeks prior to CBCT acquired during embolotherapy for HCC between 2010 and 2013 were included in the study. CBCT was acquired in each patient using a 5-s (248 projection images) or 8-s (396 projection images) protocol. Anonymised images were reviewed independently by an interventional radiologist blinded to CBCT group. MDCT was used as a reference to the patients anatomy, and performance of CBCT was compared to that of MDCT in each group. The level of concordance between CBCT and MDCT within each group was assessed for the following variables: number of foci >1 cm, largest tumour diameter, highest order branching vessel identified, image quality, diagnostic quality, signal-to-noise ratio, and contrast-to-noise ratio (CNR). CBCT radiation dose was recorded. RESULTS There was no significant difference between MDCT and CBCT within each group in the number of tumour foci >1 cm identified or size of the largest focus measured. MDCT had superior image quality compared to both CBCT groups (p<0.01), but CBCT demonstrated subsegmental branches more often in each group than MDCT. Both CBCT groups demonstrated higher CNR than MDCT (p<0.01). The dose-area product (3675±1295 versus 6598±1252 μGy·m2; p<0.001) and skin dose (119±41 versus 212±38 mGy; p<0.001) were significantly lower with 5-s CBCT than with 8-s CBCT. CONCLUSION The relationship between MDCT and CBCT in both groups was consistent. The information obtained with 5-s CBCT was equivalent to that obtained with 8-s CBCT but with a lower radiation dose.