# Monitoring of fractures with internal fixators using weight-bearing quantitative cone beam CT

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 2021 · $361,069

## Abstract

PROJECT SUMMARY / ABSTRACT
The healthcare burden of fractures is exacerbated for patients who suffer from non-unions and delayed unions.
Prediction of non-unions and development of new therapies stimulating bone growth is challenged by a lack of
quantitative, non-invasive tests to simultaneously assess the two primary aspects of bone healing: (i) mineral
density of the callus and fracture gap; and (ii) mechanical stability under weight-bearing. To address this
challenge, we proposed to use a novel extremity cone-beam CT system (CBCT) that provides a unique capability
of weight-bearing 3D imaging at high spatial resolution. This will allow measurement of the motion of bone
fragments by estimating their displacement between weight-bearing and non-weight-bearing scans of the
extremity. In addition, much like conventional CT, CBCT can perform bone mineral density (BMD) measurements
of the fracture. To enable quantitative weight-bearing assessment of fracture repair on extremities CBCT,
artifacts and image nonuniformity due to metal fixation hardware must be mitigated. The scientific premise of
this work is that the effects of metal hardware can be minimized by a combination of novel Dual Energy (DE)
techniques suitable for extremities CBCT and advanced model-based image reconstruction (MBIR) incorporating
prior knowledge of the surgical hardware. DE imaging will provide a robust correction of the attenuation value
inaccuracy due to beam hardening. Efficient, single-scan implementation of DE CBCT will be achieved using the
innovative multi-source configuration on the extremities CBCT scanner. The Known-Component Reconstruction
algorithm (KCR) will be used to address metal-induced photon starvation and nonlinear partial volume effects by
exploiting prior knowledge of the shape and pose of the metal component. Inherent in this approach is a
component registration step that will provide a precise estimate of implant deformation under weight-bearing,
resulting in a novel approach to asses fracture stability. The following specific aims will be pursued: 1) Enable
Dual Energy CBCT from multi-source CBCT data by means of an novel DE MBIR algorithm and optimized DE
imaging protocols to yield detection of ~5% relative change in bone mineral density in phantoms; 2) Integrate
prior knowledge of surgical hardware in MBIR DE reconstruction by exploiting accurate (~0.5 mm Target
Registration Error) deformable 3D-2D registration of fracture fixation hardware to estimate component pose and
deformation; 3) Perform clinical translation of the Known-Component DE algorithms in implanted cadaveric
extremities under controlled load and in pilot patient study. Fracture patients will be imaged at 2, 4, 8 and 12
weeks post-fracture to demonstrate detection of changes in callus mineralization during fracture repair. This
research will establish an innovative quantitative imaging approach for simultaneous, non-invasive assessment
of two primary biomarkers of fracture repair: mi...

## Key facts

- **NIH application ID:** 10140345
- **Project number:** 5R01EB025470-04
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** JOSEPH Webster STAYMAN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $361,069
- **Award type:** 5
- **Project period:** 2018-07-01 → 2023-09-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10140345

## Citation

> US National Institutes of Health, RePORTER application 10140345, Monitoring of fractures with internal fixators using weight-bearing quantitative cone beam CT (5R01EB025470-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10140345. Licensed CC0.

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