Abdominal diffusion mapping with use of a whole-body echo-planar system

Area of Science:

• Medical Imaging
• Biophysics
• Radiology

Background:

• Diffusion measurements provide insights into tissue microstructure.
• Magnetic resonance (MR) imaging offers a non-invasive method for assessing tissue properties.
• Apparent diffusion coefficients (ADCs) quantify water molecule diffusion within tissues.

Purpose of the Study:

• To measure apparent diffusion coefficients (ADCs) of water in the liver, spleen, kidney, and muscle.
• To establish baseline ADC values in healthy volunteers.
• To investigate ADC variations in patients with abdominal pathologies.

Main Methods:

• Utilized a 1.5-T echo-planar MR imaging system.
• Employed a stimulated-echo acquisition mode (STEAM)-type excitation with echo-planar imaging (EPI) readout.
• Scanned ten healthy volunteers and nine patients with various liver conditions.

Main Results:

• Established mean ADC values for healthy volunteers: liver (1.39 x 10⁻³ mm²/sec), spleen (0.95 x 10⁻³ mm²/sec), muscle (1.99 x 10⁻³ mm²/sec), and kidney (3.54 x 10⁻³ mm²/sec).
• Observed distinctive ADC values in patients with hepatic diseases, including liver cysts (3.9-5.3 x 10⁻³ mm²/sec), hemangiomas (2.0-2.8 x 10⁻³ mm²/sec), hepatocellular carcinoma (1.7 x 10⁻³ mm²/sec), and cirrhosis (0.9-1.2 x 10⁻³ mm²/sec).
• Demonstrated significant differences in ADC values between healthy organs and diseased states.

Conclusions:

• In vivo diffusion measurements using MR imaging are feasible for abdominal organs.
• ADC values show potential for differentiating between normal and abnormal abdominal tissues.
• This technique may aid in the identification and classification of abdominal diseases.