Diffusion-Weighted Imaging in the Assessment of Brain Abscesses Therapy
Fabiola W. Cartes-Zumelzua,
Ioannis Stavroub,
Mauricio Castilloc,
Edith Eisenhubera,
Engelbert Knospb and
Majda M. Thurnhera
a Department of Radiology, Neuroradiology Section, University Hospital, Vienna
b the Department of Neurosurgery, University Hospital, Vienna
c the Department of Neuroradiology, University of North Carolina School of Medicine, Chapel Hill
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FIG 1. Patient 1. A 40-year-old man with mild ataxia and homonymous hemianopia. CRP level was initially 0.5 mg/dL and did not change in the clinical course. WBC count was mildly increased initially and decreased soon after surgical drainage. DW images were well correlated with conventional MR images, showing no re-accumulation of pus.
A, Axial contrast-enhanced T1-weighted image shows a ring-enhancing lesion in the left occipital region, with perifocal edema.
B and C, Trace DW images show a hyperintense lesion and a low ADC indicating restricted diffusion. Clinical and imaging findings were consistent with brain abscess.
D–F, Four days after surgical drainage, contrast-enhanced T1-weighted image (D) shows that the lesion is diminished, with predominantly low signal intensity on a DW image (E) and a high ADC on ADC map (F); these finding suggest clear fluid in the abscess cavity.
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FIG 2. Patient 1. Additional images.
A–C, Follow-up images obtained 9 days later (2 weeks after drainage) show further decrease in the size of the abscess (A), persistence of low signal intensity on DW imaging (B), and a high ADC (C).
D-F, Last DW images (E) (1 month after drainage) show no enhancement and no abnormality.
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FIG 3. Patient 2. A 31-year-old man with fever, seizures, and weakness of the left upper extremity. DW images were superior to conventional MR images showing re-accumulation of pus and well correlated with increased CRP levels and WBC counts.
A–C, Axial contrast-enhanced T1-weighted shows a peripheral enhancing lesion with a hypointense center in the right parietal region. Hyperintensity at DW imaging (B) and a low ADC (C) suggest abscess formation with restricted diffusion due to pus.
D–F, One day after surgery, images show decreased size of the abscess (D), hypointensity at DW imaging (E), and a high ADC of 2.56 x 10 –3mm 2/s (F).
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FIG 4. Patient 2. Additional MR images.
A–C, Follow-up image (A) obtained 15 days after surgical intervention shows reduced size of the abscess cavity. Corresponding DW image (B) shows hyperintensity in the abscess cavity with a decreased ADC to 0.76 x 10 –3mm 2/s (C), indicating reappearance of pus. Second drainage was performed 1 day later.
D–F, Forty days after second intervention, follow-up images show resolution of the abscess cavity, with residual hypointensity on contrast-enhanced T1-weighted image and no abnormality on DW images.
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