Image-based precision medicine

In the Cardiac Center’s 3D Imaging Review Suite, the result of an innovative collaboration between diagnostic imaging experts, cardiac clinicians take images from sources such as 3D echocardiograms, CTs and MRIs, and review these images through SlicerVR — virtual reality (VR) software based on the open-source platform 3D Slicer and further developed by a team led by CHOP cardiac anesthesiologist Matt Jolley, MD. The resulting virtual images can be resized, interacted with and even stepped into.

With recent funding from the Cardiac Center, CHOP clinicians are leveraging the capabilities of VR to educate surgical trainees, develop novel interventions and deliver highly-individualized, precision care.

Mapping surgical procedures

In the clinical care setting, 3D images can give surgeons access to latent information not always visible on a 2D scan. This is particularly the case when planning complicated surgical procedures, such as complex ventricular septal defects (VSD) repairs.

In the case of a complex VSD, an echocardiogram doesn’t always show the true size and location of the defects, a problem further complicated by “fake-outs,” gaps between the trabecula that may appear on the echocardiogram as holes. Without 3D imaging, surgeons and complex VSD patients are more susceptible to lengthy, imperfect procedures and residual defects.

While a VSD can sometimes be closed through transcatheter intervention, it’s critical that the procedure not disrupt the chordae tendinea — the delicate structural support system of the tricuspid valve — which can be difficult to see on a 2D scan.

In order to plan the appropriate intervention for a patient with multiple VSDs, a cardiac clinician needs to know exactly where — and how large — the defects are.

A Cardiac Center clinician reviews a patient’s heart anatomy in virtual reality.

The right tool for the job

In the Cardiac Center’s 3D Imaging Review Suite, cardiac clinicians can review a patient’s anatomy in multiple modalities — including 3D PDFs, printed models and VR — to ensure they have all of the information necessary to make clinical decisions that optimize a patient’s care.

While other 3D technologies — such as 3D PDFs or printed models — are often the tools of choice for surgical procedures involving the spatial relationships of extracardiac vessels, VR provides a detailed image of the heart’s internal anatomy while also being less costly and more time efficient than other modalities.

“We’ve gone from 3D technology being a helpful modality to being a routine clinical tool,” says Reena Ghosh, MD, who runs the 3D Imaging Review Suite with cardiac MRI attending Kevin Whitehead, MD, PhD. “Now a surgeon can walk through a patient’s heart before a case and figure out the best approach for that child.”

A Cardiac Center clinician uses VR to simulate device selection and placement.

The following case study demonstrates the utility of VR in complex VSD repairs.

A second chance

At one week old, a baby boy with congenital heart disease underwent surgery in Seattle, W.A. to repair a large muscular VSD and aortic coarctation. The coarctation was repaired, and a pulmonary artery band was placed, temporarily restricting blood flow to the lungs. The family subsequently moved to Pennsylvania, where the child was referred to Jonathan Chen, MD, Co-director of the Cardiac Center and Chief of the Division of Cardiothoracic Surgery. When at 1 year old, the child experienced changes in oxygen level and two brief periods of altered consciousness, a second surgery was recommended.

MRI imaging suggested that the patient’s VSD would be very difficult to get to. For further evaluation, Dr. Chen requested VR imaging of the heart. In the 3D Imaging Review Suite, the patient’s MRI scans were put into Mimics — image processing software used for 3D modeling. The resulting 3D image could be viewed on a 2D screen. From this perspective, it was clear that the defect was much larger than originally thought — likely too large for a transcatheter repair. Together with Jack Rome, MD, FACC, Dr. Chen then viewed the images in VR. With the heart anatomy enlarged, both doctors were able to step inside the virtual heart and consider the VSD up close.

The team determined that the VSD should be repaired surgically in the Cardiac Center’s hybrid operating room, a procedural space that combines the aspects of a traditional operating room with an image-guided interventional suite. If surgical closure didn’t work, Dr. Rome would be there to close the defect with a transcatheter device.

What Dr. Chen found, however, was that the VR imaging provided a near-perfect replica of the patient’s heart anatomy, down to the exact distance between the defect and other structural aspects of the heart. The repair was difficult, but Dr. Chen was ultimately able to surgically close the VSD with no residual defects.

An annotated heart specimen is explored in virtual reality.

Precision imaging

This case illustrates that the use of VR in pre-surgical planning enables a surgeon to see the heart anatomy exactly as it is, from multiple angles and perspectives, thereby eliminating surprises and preventing additional, unexpected procedures. 

Says Dr. Chen, “There’s nothing else that gives you that kind of GPS.”

The Cardiac Center is currently conducting research that compares virtual reality to other 3D technologies with the goal of determining which technology is most beneficial for different types of heart disease.

To make a referral, call 267-426-9600 or contact us online.