Shreyas Vasanawala, MD/PhD

Overview:

Associate Professor of Radiology
Chief of Body MRI & MRI Co-Director
Lucile Packard Children's Hospital and Stanford Hospital & Clinics
Stanford University
650-723-8087

Clinical Interests:

Abdominal and pelvic MRI: Application of fast volumetric imaging to adult and pediatric abdominal tumors, solid organ transplants, renal function, and inflammatory bowel disease.

Pediatric Cardiovascular MRI: MRI of congenital heart disease.

Pediatric Musculoskeletal MRI: Applications of fast high-resolution volumetric MRI to sports injuries, tumors, and inflammatory arthropathies.

Research Interests and Members/Collaborators:

Novel MRI hardware: We are actively developing miniaturized radiofrequency receiver arrays for optimized and personalized MRI exams.

Researchers:
Left image is from a 3D acquisition on a young child with a custom high-density coil. Middle image is a reformat of the source data and compares favorably with directly acquired 2D images in the same plane. This capability to reformat into arbitrary plans can greatly speed MRI exams.
Fast MRI techniques: To enable more children to undergo MRI and to enable higher resolution imaging in adults, we are exploring methods that combine advanced parallel imaging, compressed sensing, motion correction, and higher dimensional data acquisition strategies.

Researchers:
Compressed sensing acquisition in an MRA on a child with four fold acceleration. a) and c) are parallel imaging reconstructions, whereas b) and d) are compressed sensing reconstructions with the L₁-SPIRiT algorithm. Note nicely recovered features with the compressed sensing algorithm.

Similar example, but of compressed sensing image reconstructions of an MRA in a four year old with 12.5 fold acceleration of image acquisition.

Compressed sensing acquisition enables acceleration to restrict data acquisition to only a portion of the cardiac and respiratory cycles, thereby reducing motion artifacts.

Highly accelerated liver dynamic contrast enhanced exam with 4 second temporal resolution.

Similar highly accelerated acquisition, this time in an individual with rapidly enhancing hepatocellular carcinomas that only hold on to contrast briefly.

Example of navigated T1-weighted acquisitions, which enable free-breathing contrast-enhanced exams. Note hemangioma (black arrow) and ring-enhancing metastasis (white arrow). The metastasis is evident only with navigation (right image), not without (left image).

Magnitude image from a compressed-sensing time resolved volumetric phase contrast acquisition shows nice demonstration of a right coronary artery in a child, despite the small structure, fast movement, and high heart rate.
Quantitative MRI methods: Development and validation of accurate and precise cardiovascular flow and function measurements, noninvasive renal function assessment, and tumor therapy response.

Researchers: