Diagnostic Accuracy of Perfusion CT in Differentiating Brain Abscess from Necrotic Tumor
Orasa Chawalparit MD*, Chenchira Artkaew MD*, Thanomsak Anekthananon MD**, Nanthasak Tisavipat MD***, Panida Charnchaowanish BSc*, Tumtip Sangruchi MD****
Affiliation : * Department of Radiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand ** Department of Preventive Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand *** Department of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand **** Department of Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
Objective : To evaluate the diagnostic accuracy of perfusion computed tomography (CTP) in differentiating
between brain abscess and necrotic tumor.
Material and Method: Prospective study was performed in patients suspected of a space taking lesion in
the brain. CTP was done at the suspected levels and post-processing measurement of cerebral blood
volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and permeability surface index (PS) were
evaluated at ring enhanced area, central non-enhanced area, edema and contralateral normal brain.
Results : Seventeen patients with 21 lesions were studied. Of the 21 lesions, 12 were abscess and nine were
tumors. By comparing means, only MTT at the ring enhanced area showed statistically significant difference
between brain abscess and tumor (p = 0.009, 95% CI = 1.403 to 4.900). When ratio of CBV, CBF, and MTT of
the ring enhanced area and contralateral normal brain were analyzed (CBVr, CBFr, MTTr respectively), there
were significant differences of CBVr and CBFr between the two groups (p = 0.003, 95% CI = -4.266 to -1.051
and p = 0.006, 95% CI = -9.934 to -1.969 respectively). With the threshold of CBVr more than or equal to 1.5
and CBFr more than or equal to 1, the sensitivity, specificity, positive predictive value, negative predictive
value, and accuracy for diagnosis of tumor were 100%, 75%, 75%, 100%, and 85.7% respectively.
Conclusion : The CTP was shown to be useful in differentiating brain abscess from tumor. With CBVr less than
1.5, tumor can be excluded.
Keywords : Brain abscess, Brain neoplasms, Diagnosis, Differential, Necrosis, Tomography, X-ray computed
