Yawu Liu MD, Presenter: Nothing to Disclose

Ville Soppi MD, Abstract Co-Author: Nothing to Disclose

Mervi Kononen MSc, Abstract Co-Author: Nothing to Disclose

Jaakko Rinne MD, Abstract Co-Author: Nothing to Disclose

Ritva Liisa Vanninen MD, Abstract Co-Author: Nothing to Disclose

To study if subarachnoid hemorrhage (SAH) can cause changes in the apparent diffusion coefficient (ADC) in normal-appearing brain tissue.

Fifty-three patients (51 ± 10 years) with aneurysmal SAH underwent conventional and diffusion-weighted MRI 9 ± 2 days after SAH to evaluate possible ischemic lesions caused by SAH, its treatment or vasospasm. Sixteen healthy age-matched volunteers (52 ± 15 years) also underwent MRI with the same imaging protocol. All patients were treated either surgically (nonferromagnetic clips, n=39) or endovascularly (detachable coils, n=14) before MRI. ADC-values were measured from bilateral regions in the normal-appearing gray and white matter (parietal, frontal, temporal, occipital lobes, and cerebellum), body of lateral ventricle, caudate nucleus, putamen, thalamus, and pons.

In SAH patients, the ADC values (×10¯³mm²/s) in normal-appearing white matter were significantly higher than those of healthy volunteers (parietal lobe 0.77 ± 0.04 vs. 0.74 ± 0.05, p =0.004; frontal lobe 0.81 ± 0.07 vs. 0.78 ± 0.04, p=0.011; temporal lobe 0.79 ± 0.06 vs. 0.75 ± 0.04, p<0.001; occipital lobe 0.78 ± 0.05 vs. 0.75 ± 0.05, p=0.013, cerebellum 0.69 ± 0.04 vs. 0.66 ± 0.05, p=0.004). The ADC values of cortical or deep gray matter, body of lateral ventricle, and pons did not significantly differ in patients and volunteers, with the single exception in temporal lobe cortical gray matter (0.79 ± 0.06 vs. 0.75 ± 0.04, p<0.001). In the 33 patients with middle cerebral artery or internal carotid artery aneurysms, the ADC-values tended to be lower in ipsilateral parietal, frontal, and temporal gray matter (p<0.118) than compared to the contralateral side.

SAH and its treatment may cause slight vasoedema which is undetectable on T2 weighted and isotropic diffusion weighted images but is detectable by measuring the ADC-values at subacute stage.

Liu, Y, Soppi, V, Kononen, M, Rinne, J, Vanninen, R, Apparent Diffusion Coefficient in Normal Appearing Brain Tissue in Patients with Subarachnoid Hemorrhage.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4406643.html