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Differentiation of pyogenic and fungal brain abscesses with susceptibility-weighted MR sequences
Ronald Antulov1, Kresimir Dolic, Julia Fruehwald-Pallamar
1Department of Radiology, Clinical Hospital Centre Rijeka, Rijeka, Croatia.
Introduction:
Conventional magnetic resonance imaging (MRI) techniques are insufficient to determine the causative agent of brain abscesses. We investigated: (1) the value of susceptibility-weighted MR sequences (SWMRS) in the differentiation of fungal and pyogenic brain abscesses; and (2) the effect of different SWMRS (susceptibility-weighted imaging (SWI) versus venous blood oxygen level dependent (VenoBOLD)) for the detection of specific imaging characteristics of pyogenic brain abscesses.
Methods:
We studied six patients with fungal and ten patients with pyogenic brain abscesses. Imaging characteristics on conventional MRI, diffusion-weighted imaging (DWI) and SWMRS were recorded in all abscesses. All lesions were assessed for the presence of a "dual-rim sign" on SWMRS.
Results:
Homogenously hyperintense lesions on DWI were present in 60 % of patients with pyogenic abscesses, whereas none of the patients with fungal abscesses showed such lesions. On SWMRS, 90 % of patients with pyogenic abscesses and 60 % of patients with fungal abscesses had only lesions with a low-signal-intensity rim. On SWI, the dual-rim sign was apparent in all pyogenic abscesses. None of the fungal abscesses on SWI (P = 0.005) or any of the pyogenic abscesses on VenoBOLD (P = 0.005) were positive for a dual-rim sign.
Conclusions:
In fungal abscesses, the dual-rim sign is not present but a prominent peripheral rim or central susceptibility effects on SWI will be seen. The appearance of pyogenic abscesses on SWMRS depends on the used sequence, with the dual-rim sign a specific feature of pyogenic brain abscesses on SWI.
Insights
Susceptibility-weighted MR sequences (SWMRS) help differentiate fungal and pyogenic brain abscesses. The dual-rim sign on susceptibility-weighted imaging (SWI) specifically identifies pyogenic abscesses, aiding diagnosis.
Area of Science:
- Radiology
- Neuroimaging
- Medical Diagnostics
Background:
- Conventional MRI lacks specificity in differentiating brain abscess etiologies.
- Distinguishing between fungal and pyogenic brain abscesses is crucial for effective treatment.
Purpose of the Study:
- To evaluate susceptibility-weighted MR sequences (SWMRS) for differentiating fungal and pyogenic brain abscesses.
- To assess the utility of different SWMRS, specifically susceptibility-weighted imaging (SWI) and VenoBOLD, in detecting pyogenic abscess characteristics.
Main Methods:
- Retrospective analysis of six fungal and ten pyogenic brain abscess cases.
- Assessed conventional MRI, diffusion-weighted imaging (DWI), and SWMRS findings.
- Evaluated for the presence of a "dual-rim sign" on SWMRS.
Main Results:
- Homogenously hyperintense DWI lesions were observed in 60% of pyogenic abscesses, but not in fungal abscesses.
- A low-signal-intensity rim was present in 90% of pyogenic and 60% of fungal abscesses on SWMRS.
- The dual-rim sign was evident in all pyogenic abscesses on SWI, but absent in fungal abscesses and not detected on VenoBOLD.
Conclusions:
- The dual-rim sign is a specific indicator of pyogenic brain abscesses on SWI.
- Fungal abscesses exhibit different SWI characteristics, such as prominent rims or central susceptibility effects.
- SWMRS, particularly SWI, enhances the differentiation of brain abscess types compared to conventional MRI.
