Tharindu DeSilva reports clinical utility of LevelCheck.

October 26, 2016

The “LevelCheck” algorithm for automatic radiographic labeling of the spine during surgery was evaluated by Tharindu De Silva and colleagues in a recent paper published in Spine. The clinical utility was assessed, and scenarios in which LevelCheck was most likely to be the beneficial were assessed in a retrospective study of 398 cases.

The results showed that LevelCheck was helpful in 42.2% of the cases (168/398), to improved confidence in 30.6% of the cases (122/398), and in no case diminished performance (0/398), supporting its potential as an independent check and assistant to decision support in spine surgery.

The scenarios for which LevelCheck was most likely to be beneficial included: cases with a lack of conspicuous anatomical landmarks; level counting across long spine segments; vertebrae obscured by other anatomy (e.g., shoulders); poor radiographic image quality; and anatomical variations/abnormalities.

The method demonstrated 100% geometric accuracy (i.e., correctly overlaid spine labels within the correct vertebral level in all cases) and did not introduce ambiguity in image interpretation.  The study shows LevelCheck to be a potentially useful means of decision support in spine surgery target localization and motivates translation to prospective clinical studies.

Read the full paper in Spine.



I-STARs at 102nd RSNA Meeting in Chicago

October 6, 2016

I-STARs present their research at the 102nd RSNA assembly and annual meeting in Chicago, Illinois.

Dr. Michael Brehler discussed “Quantitative Assessment of Trabecular Bone Microarchitecture Using High-Resolution Extremities Cone-Beam CT” on  Sunday November 27th  from 11:55-12:05pm.

Jeff Siewerdsen, PhD presented a talk entitled, Open Gantry Systems: Advances, Challenges, and New Applications on Sunday November 27th from 2:00-3:0 30pm.

Tharindu De Silva, PhD presented research on “Development and Clinical Translation of the “LevelCheck” Algorithm for Decision Support in Spine Surgery” at the Physics Tuesday Poster Discussion on Tuesday, Novmeber 29th from 12:15-12:45pm.

Dr. Jennifer Xu discussed “A Point-of-Care Cone-Beam CT System for Imaging of Intracranial Hemorrhage: Performance Characterization for Translation to Clinical Studies” on Wednesday, November 30th from 11:30-11:40am.

Matthew Jacobson, PhD presented his research on “Mobile C-Arm Cone-Beam CT: A New Prototype Incorporating Model-Based Image Reconstruction and Soft-Tissue Contrast Resolution” on Wednesday, November 30th from 11:40-11:50am.

Wojciech Zbijewski, PhD participated in an educational talk on Extremity CT, specifically MSK on Thursday, December 1st from 4:30-6:30pm.


Paper by Jen Xu: Image quality for a new cone-beam CT head scanner

September 16, 2016

A recent publication in Physics in Medicine and Biology entitled: “Evaluation of detector readout gain mode and bowtie filters for cone-beam CT imaging of the head”, reports evaluation of the efficacy and benefits of various detector gain modes and/or use of bowtie filters on the image quality (in terms of contrast and noise) in a Cone-Beam CT (CBCT) system, with application to high-quality imaging of low-contrast lesions in the head. The work develops a model of digitization noise as related to inherent additive electronics noise and panel gain mode, with applications to generalized analysis of the effects of gain mode and imaging dose on detective quantum efficiency analysis. Three bowtie filters of varying curvature and thickness were designed to evaluate tradeoffs in image quality from bowtie shape. The changes to dose distribution within the object imparted by bowtie filters was evaluated with a fast, GPU-based Monte Carlo simulation. The results from this evaluation were used in determination of the clinical protocols for a prototype CBCT scanner dedicated to imaging of acute intracranial hemorrhage.

This paper includes co-authors from Johns Hopkins Department of Biomedical Engineering (A. Sisniega, W. Zbijewski, H. Dang, JW. Stayman, JH. Siewerdsen), Department of Neuropathology (V. Koliatsos), Department of Neuroradiology (N. Aygun) and Carestream Health (DH. Foos, X. Wang).

J. Xu et al., Phys. Med. Biol. 61:5973 (2016)

Qian Cao Improving High-Resolution CT

July 14, 2016

Graduate student Qian Cao was chosen for the prestigious Howard Hughes Medical Institute International Student Research Fellowship, awarded to just 45 international predoctoral students studying in the United States. The award provides funding through the fifth year of PhD studies.

Qian’s research involves creating new technology for high-resolution CT scanning to detect minute bone changes that signal the early stages of osteoarthritis

“Osteoarthritis,” Cao explains, “is growing steadily more prevalent in the United States as the population ages.” Some estimates suggest that more than 67 million individuals will have osteoarthritis by 2030. “New research is showing that it can be detected in the early stages of progression, before damage to the joint and cartilage begin.”

Cao’s research is under way in the I-STAR Laboratory at Johns Hopkins, where he works under the mentorship of Dr. Wojciech Zbijewski and Dr. Jeffrey Siewerdsen in Biomedical Engineering at Hopkins. “Qian’s work is helping to break the conventional limits of spatial resolution in CT,” says Zbijewski.

(Link to full article)

ISTARS Attend The 4th International Conference on Image Formation in X-Ray Computed Tomography

July 8, 2016

I-STARs will present new research in CT Imaging at the 4th International Conference on Image Formation in X Ray Computed  Tomography between July 18th and July 22nd, 2016 at the Welcome Kongresshotel Bamberg, Germany.

Aswin Mathews, PhD presents research related to “Design of  Dual  Multiple  Aperture  Devices  forDynamical Fluence Field Modulated CT” (General Session Tuesday July 19 9:00-9:20)

Alejandro Sisniega, PhD presents his research on “Motion Estimation Using a Penalized Image Sharpness Criterion for Resolution Recovery in Extremities Cone-Beam CT” (CBCT session, Thursday July 21, 15:40-16:00)

Grace Gang, PhD discusses “Task-Based Design of Fluence Field Modulation in CT for Model-Based Iterative Reconstruction” (Iterative Reconstruction Session, Thursday July 21, 11:20-11:40am)

PhD candidate, Steven Tilley shows research on “Modeling Shift-Variant X-Ray Focal Spot Blur for High-Resolution Flat-Panel Cone-Beam CT” (Thursday July 21, 13:20-15:00, Poster Session 3)

Hao Dang provides insight on “Task-Based Regularization Design for Detection of Intracranial Hemorrhage in Cone-Beam CT” (CBCT Session Thursday July 21 16:20-16:40)