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Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Diffusion-weighted imaging in brain aspergillosis
M Charlot1, J-B Pialat, N Obadia
1Department of Radiology, Claude Bernard University, Hospices Civils de Lyon, Lyon, France.
Abstract:
Brain aspergillosis is a rare pathology, occurring mainly in immunocompromised patients, responsible for multiple cerebral septic infarctions. Some researchers have described magnetic resonance (MR) findings in cerebral invasive aspergillosis, but diffusion-weighted imaging (DWI) has rarely been reported, especially in typical non-enhancing lesions, while it may be helpful for early differential diagnosis and may allow earlier antifungal treatment. We describe three cases of patients presenting brain aspergillosis, with MR imaging including diffusion-weighted sequences and apparent diffusion coefficient (ADC) cartography. The three patients described in this study presented a total of 23 circular lesions, and one patient presented an infarction area in the territory of the right middle cerebral artery. Lesions were ring-enhancing for one patient, and presented no enhancement for the other two. Eleven lesions were very bright on DWI, with reduced ADC values. Twelve lesions, either enhancing or not enhancing, presented a 'target-like' aspect with central and peripheral hypointense areas on DWI, corresponding to higher ADC value areas, and intermediate marked hypersignal on DWI. This typical aspect of aspergillosis lesions on DWI may allow early diagnosis and treatment of cerebral aspergillosis, and is helpful for differentiating aspergillosis lesions from other infectious or malignant lesions affecting immunocompromised patients.
Insights
Diffusion-weighted imaging (DWI) reveals characteristic patterns in brain aspergillosis, aiding early diagnosis. These findings help differentiate fungal infections from other brain lesions in immunocompromised patients.
Area of Science:
- Neurology
- Radiology
- Infectious Diseases
Background:
- Brain aspergillosis is a rare, severe infection primarily affecting immunocompromised individuals, often causing cerebral infarctions.
- Magnetic resonance (MR) imaging is used to diagnose brain aspergillosis, but diffusion-weighted imaging (DWI) findings, particularly in non-enhancing lesions, are less understood.
- Early diagnosis is crucial for timely antifungal treatment to improve patient outcomes.
Observation:
- This study analyzed MR imaging, including DWI and apparent diffusion coefficient (ADC) mapping, in three patients with brain aspergillosis.
- A total of 23 circular lesions were observed across the patients, with one also showing an infarction in the middle cerebral artery territory.
- Lesions exhibited varied enhancement patterns: one ring-enhancing, two non-enhancing.
Findings:
- Eleven lesions showed high signal intensity on DWI with reduced ADC values.
- Twelve lesions displayed a 'target-like' appearance on DWI, with central and peripheral hypointense areas (higher ADC) and intermediate hypersignal.
- This 'target-like' DWI appearance is a typical finding in brain aspergillosis.
Implications:
- The characteristic DWI 'target-like' sign can facilitate early diagnosis of brain aspergillosis.
- This imaging finding is valuable for differentiating aspergillosis from other infectious or malignant brain lesions in immunocompromised patients.
- Earlier diagnosis via DWI may enable prompt initiation of antifungal therapy, potentially improving prognosis.
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