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Dyke award. Gd-DTPA-enhanced MR imaging of experimental bacterial meningitis: evaluation and comparison with CT
V P Mathews1, M A Kuharik, M K Edwards
1Department of Radiology, University Hospital, Indianapolis, IN 46223.
Abstract:
Gd-DTPA-enhanced MR images of experimental bacterial meningitis were obtained after Staphylococcus aureus was inoculated directly into the cisterna magna of four dogs. Each animal was studied with both unenhanced and enhanced MR and CT with Gd-DTPA and meglumine iothalamate, respectively. The enhancement patterns resulting from these techniques were compared and images were correlated with histopathology. All animals demonstrated abnormal leptomeningeal enhancement on MR with Gd-DTPA, but only one of four dogs exhibited abnormal contrast enhancement on CT. In these animals Gd-DTPA-enhanced MR also identified complications of meningitis, such as ventriculitis and cerebritis, more effectively than CT did. Unenhanced MR was not helpful in identifying meningitis. Histologic evaluation demonstrated that the abnormal areas of contrast enhancement on MR and CT correlated with inflammatory cell infiltration. However, some regions of mild leptomeningitis, ependymitis, and cerebritis identified histologically did not demonstrate abnormal enhancement. Since the animal model used was clinically and pathologically similar to human meningitis, we propose that Gd-DTPA-enhanced MR will subsequently be found more effective than unenhanced MR and IV contrast-enhanced CT for demonstrating meningitis and its complications in humans.
Insights
Gadolinium-DTPA-enhanced MRI effectively detects bacterial meningitis and complications in dogs, outperforming CT scans. This imaging technique shows promise for human meningitis diagnosis.
Area of Science:
- Veterinary Neurology
- Medical Imaging
- Infectious Diseases
Background:
- Bacterial meningitis is a serious infection affecting the central nervous system.
- Accurate and early diagnosis is crucial for effective treatment and patient outcomes.
- Current imaging modalities have limitations in detecting meningitis and its complications.
Purpose of the Study:
- To compare the efficacy of gadolinium-DTPA-enhanced magnetic resonance imaging (MR) and computed tomography (CT) in diagnosing experimental bacterial meningitis.
- To evaluate the ability of these imaging techniques to identify complications such as ventriculitis and cerebritis.
- To correlate imaging findings with histopathological results.
Main Methods:
- Bacterial meningitis was induced in four dogs by direct inoculation of Staphylococcus aureus into the cisterna magna.
- Animals underwent unenhanced and Gd-DTPA-enhanced MR imaging, as well as meglumine iothalamate-enhanced CT.
- Imaging results were compared with each other and correlated with post-mortem histopathology.
Main Results:
- All dogs showed abnormal leptomeningeal enhancement on Gd-DTPA-enhanced MR.
- Only one dog exhibited abnormal contrast enhancement on CT.
- Gd-DTPA-enhanced MR identified complications like ventriculitis and cerebritis more effectively than CT.
- Unenhanced MR was not effective in diagnosing meningitis.
Conclusions:
- Gd-DTPA-enhanced MR is superior to CT for detecting experimental bacterial meningitis and its complications in this canine model.
- The findings suggest Gd-DTPA-enhanced MR may be a more effective diagnostic tool for human meningitis than unenhanced MR or IV contrast-enhanced CT.
- Histopathology confirmed inflammatory changes correlating with enhancement patterns, though some mild inflammation was not visualized on imaging.