Hernan Jara PhD, Presenter: Patent holder, qMRI algorithms Research Grant, General Electric Company Royalties, World Scientific Publishing Co

Asim Zia Mian MD, Abstract Co-Author: Stockholder, Boston Imaging Core Lab, LLC

Stephan W. Anderson MD, Abstract Co-Author: Nothing to Disclose

Osamu Sakai MD, PhD, Abstract Co-Author: Speaker, Bracco Group Speaker, KYORIN Holdings, Inc Speaker, Eisai Co, Ltd

Jorge A. Soto MD, Abstract Co-Author: Nothing to Disclose

Alexander M. Norbash MD, Abstract Co-Author: Stockholder, Boston Imaging Core Laboratories, LLC Co-founder, Boston Imaging Core Laboratories, LLC

Transient brain enhancement of up 30% has been visualized with fast IR-prepared pulse sequences in combination with matching image-processing algorithms. To our knowledge, this is the first demonstration of an MRI technique for visualizing the CE effects of normal saline in the brain.

Normal saline (NS) is a nontoxic and biologically compatible sodium chloride aqueous solution that can significantly increase the MR relaxation times (T1, T2, T2*) of blood by transient hematocrit reduction (hemodilution) (Fig. 1a). The purpose of this work is to describe inversion recovery (IR) T1-weighted dynamic pulse sequences and the image processing algorithms suitable for visualizing the contrast enhancement effects of NS injections.

Normal saline can be used as a T1-lengthening MRI contrast agent that is safe, widely available, and inexpensive. Practical experience with NS as an MRI contrast agent is at an embryonic stage: the pulse sequences and processing algorithms described herein could become standard tools for NS-CE-MRI examinations.

HIPAA compliant prospective study approved by our IRB: MRI scanning (1.5T Achieva, Philips Healthcare) with head array and body coil for RX/TX. Three and five patients were scanned with an IR-EPI and IR-TSE sequence respectively. The IR pulse sequences were run during and after the NS injection for up to 5min: 100cc of NS were power injected into antecubital veins at 3-4cc/s. NS injection related enhancement of up to 30% was observed with both pulse sequences. The IR-TSE pulse sequence (Fig. 1b) produced improved image quality than IR-EPI albeit at threefold slower temporal resolution (10s). IR-TSE begins with a large flip angle pulse; at time TI, an excitation pulse is applied; it converts the partially recovered longitudinal magnetizations into transverse magnetizations, which are then interrogated at multiple spin echo times according with turbo spin echo (TSE) acquisition principle. Images were processed with Mathcad (2001i, PTC, Needham, MA) algorithms to map maximum enhancement (maxENH), area under the curve (AUC), time-to-peak (TTP), mean-transit-time (MTT), and to generate ROI time series in selected areas.

Jara, H, Mian, A, Anderson, S, Sakai, O, Soto, J, Norbash, A, MRI Scanning and Image Processing Techniques for Visualizing the Dynamic Contrast Enhancement Effects of Normal Saline Injections.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14013988.html