J Korean Neurosurg Soc.  2007 Jun;41(6):371-376.

Preoperative Assessment of Cystic Brain Lesion: Significance of Diffusion-Weighted Image and ADC (Apparent Diffusion Coefficiency) Values

• Choi HC
• Lee SW
• Ji C

Abstract

OBJECTIVES
The aim of this study was to investigate the usefulness of diffusion-weighted imaging (DWI) and apparent diffusion coefficiency (ADC) in distinguishing brain abscesses from cystic or necrotic brain tumors, which are difficult to be differentiated by conventional magnetic resonance imaging techniques.
METHODS
Seven patients with brain abscesses and ten patients with cystic brain tumors were studied from September 2003 to October 2005. Abscess, subdural empyema and ventriculitis were categorized to the abscess group and cystic or necrotic brain gliomas or metastatic brain tumors into the tumor group. Preoperative magnetic resonance images were perfomed in all patients and diffusion-weighted images and apparent diffusion coefficiency values of lesions were calculated directly from software of 1.5 tesla MRI (General Electrics, USA). The ratio of the ADC of the lesion to contralateral regional ADC was also measured (relative ADC, rADC).
RESULTS
The average ADC value of pyogenic abscesses group was 0.82+/-0.14x10-3 (mean+/-S.D.) mm(2)/s and mean rADC was 0.75. Cystic or necrotic areas had high ADC values (2.49+/-0.79x10-3 mm(2)/s, mean rADC=2.14). ADC and rADC values of abscesses group showed about three times lower values than those of cystic or necrotic tumor group.
CONCLUSION
This study results based on numerical comparison of signal intensities and quantitative analysis to distinguish between brain abscess and cystic or necrotic tumor, DWI and ADC mapping are thought to be very useful diagnostic tools.

Keyword

Abscess; Brain tumor; Magnetic resonance imaging; Diffusion-weighted imaging; Apparent-diffusion coefficiency

MeSH Terms

Abscess
Brain Abscess
Brain Neoplasms
Brain*
Diffusion*
Empyema, Subdural
Glioma
Humans
Magnetic Resonance Imaging