Youichi Sato MD, Presenter: Nothing to Disclose

Eito Kozawa MD, Abstract Co-Author: Nothing to Disclose

Makoto Amanuma MD, Abstract Co-Author: Nothing to Disclose

Fumiko Kimura MD, Abstract Co-Author: Nothing to Disclose

The purpose of this study is to evaluate age-related change using the apparent diffusion coefficient value (ADC) of diffusion-weighted MRI (DWI) in the vertebrae of the lumbar spine.

Forty-two consecutive patients (26 men, 16 women; 20 to 82 years old, mean 54.8) suspected of having disk hernia were entered into the study. Inclusion criteria included normal bone marrow, determined by normal blood cell count, without history of malignant, hematologic, or systemic diseases. Patients were studied with 1.5-T MRI units (Magnetom Symphony Quantum and Sonata, Siemens, Germany) with phased-array spine coils. In addition to routine sequences, such as T1-weighted and fast short tau inversion recovery (STIR) images at sagittal image, DWIs were obtained with spin echo sequences with GRAPPA (accel. factor = 2) and the following parameters: TR = 1000, TE = 38, FOV = 280 x 280 mm, thickness = 5mm, and 3 b factors = 0, 400, and 800. The 2 groups were a young to middle-aged group (AM: 20 to 39; 11 patients) and an old-aged group (OL: 40-82; 31 patients). ADC was measured from regression using 3 b-values in each vertebra with software of MRI system. Measurement of the region of interest was done mid-sagittally, excluding cortex. Mean and standard deviation (SD) were calculated for ADCs of the L2 vertebra. The mean values of ADC were compared by unpaired t-test using commercially available software (JMP; SAS Institute Inc.). Significance was defined as P < 0.01.

The mean ADC were 0.67 +/-0.15 x 10-3 mm2/sec (mean +/-SD) for AM and 0.31+/-0.17 x 10-3mm2/sec for OL. The differences in ADCs were significant in each group (p< 0.01).

The ADC of normal bone marrow could be strongly influenced by age.

Recently ADC is used for the evaluation of vertebral metastasis, and normal ADC knowledge with aging is needed in the accurate interpretation and evaluation of vertebral metastasis.

Sato, Y, Kozawa, E, Amanuma, M, Kimura, F, Quantitative Assessment of Normal Spinal Bone Marrow Using Apparent Diffusion Coefficient with GRAPPA.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4434887.html