Objective: Discriminating pyogenic brain abscesses from cystic or necrotic tumors is
sometimes difficult with CT or conventional MR imaging. Diffusion MR imaging is a valuable
diagnostic test in cases of intracranial cystic masses.
Methods: This work was conducted from July 2008 to June 2013 on 90 patients; 43 males and 47
females. Their ages range from 5 to 70 years. All patients were subjected to routine MRI examination
and diffusion weighted imaging using 1.5 T MRI scanner. Gadolinium was given to some cases
on routine MRI. Diffusion weighted imaging was performed with a single-shot spin-echo echoplanar
pulse sequence (b=0–1000 s/mm2). The apparent diffusion coefficient values and ratio were
measured.
Results and conclusions: Patients in this study were categorized into three main groups; first group
is brain abscesses (36 cases), 91.6% of them showed restricted diffusion, second group is malignant
cystic or necrotic brain tumors, 28 cases of high grade necrotic glioma, 60.7% of them are free
diffusion, and third group is benign cystic masses, arachnoid and epidermiod cysts (11 cases); all
arachnoid cysts are free diffusion. From these results diffusion-weighted imaging is playing an
important role in discrimination of cystic intracranial masses.