MR vessel wall imaging in tubercular meningitis

Analysis of risk factors for acute cerebral infarction in patients with intracranial tuberculosis

Objective

Acute cerebral infarction is a common complication of intracranial tuberculosis (TB), causing irreversible damage to brain tissue and significantly affecting patient prognosis. This study aims to explore the risk factors associated with acute cerebral infarction in patients with intracranial tuberculosis.

Methods

We retrospectively analyzed data from eligible intracranial TB patients treated at our hospital between January 2020 and March 2023. Based on MRI findings, patients were categorized into a cerebral infarction group and a non-infarction group. Clinical data, cerebrospinal fluid (CSF) examinations, and imaging features (such as hydrocephalus, cerebral arteritis, and meningeal thickening) were compared between the two groups. Binary logistic regression analysis was used to identify risk factors for acute cerebral infarction in patients with intracranial TB.

Results

A total of 102 patients were included, with 24 in the cerebral infarction group and 78 in the non-infarction group. Male patients accounted for 87.5% in the infarction group and 58.3% in the non-infarction group. Patients with a Glasgow Coma Scale (GCS) score of 3-10 accounted for 45.8% in the infarction group compared to 15.4% in the non-infarction group. The incidence of hydrocephalus, cerebral arteritis, and meningeal thickening was significantly higher in the infarction group (37.5, 54.2, and 79.2%, respectively) compared to the non-infarction group (6.4, 6.4, and 43.6%, respectively) (p < 0.05). The parenchymal type of intracranial TB was less frequent in the infarction group (20.8%) than in the non-infarction group (56.4%), while the mixed type was more frequent in the infarction group (62.5%) compared to the non-infarction group (26.9%) (p < 0.05). Patients with meningeal thickening involving the cisterns and basal cisterns had a higher risk of cerebral infarction (p < 0.05). Multivariate binary logistic regression analysis revealed that male sex (OR = 13.56; 95% CI 1.25-38.30) and cerebral arteritis (OR = 19.32; 95% CI 0.94-37.64) were independent risk factors for cerebral infarction in intracranial TB patients.

Conclusion

Male sex and the presence of cerebral arteritis are independent risk factors for acute cerebral infarction in patients with intracranial tuberculosis.

Assessment of Post-COVID-19 Changes in Brain-Clinical and Imaging Evaluation Using MRI Vessel Wall Imaging and Complementary MRI Methods

Background/Objectives: The aim of the study was to evaluate the usefulness of vessel wall imaging and MRI in assessment of the post-COVID-19 changes in the brain. VWI is a progressive MRI technique that provides precise imaging of the pathological process in the wall of the vessel. It might help us to better understand the pathophysiology of COVID-19-related neurological lesions and may have an impact on management protocols. Methods: A total of 43 patients were included in the study; the post-COVID-19 group included 23 patients hospitalized for COVID-19 (mean age of the group: 53.52 years; 26% male, 74% female). The control group consisted of 20 patients from the general population who did not suffer from COVID-19 (mean age: 52.15 years; 35% male, 65% female). MRI examinations were performed on a 3T scanner (Biograph mMR, Siemens). The VW-MRI protocol included T1-weighted SPACE FS black-blood images, FLAIR images, SWI, and MRA. Results: Several radiological changes in post-COVID-19 patients were described: hyperintense foci in the white matter of the brain hemispheres, in the lower parts of the temporal lobes, and in the structures of the posterior cranial fossa; presence of engorgement of deep medullary veins or perivascular enhancement; presence of inflammatory vessel thickening in VWI images; changes in hippocampus size; presence of cortical atrophy; and thickening of the mucous membrane of the paranasal sinuses. The presence of atherosclerotic vessel thickening in VWI and the width of the third ventricle depended on the age of the patient. Conclusions: VWI and MRI may be useful in the assessment of post-COVID-19 lesions in the brain.

Predicting cerebral infarction in tuberculous meningitis and its prognostic significance

Aim: Tuberculous meningitis (TBM) often causes cerebral infarction, but its predictive factors are not well understood. Methods: Patients aged ≥13 years admitted with TBM were enrolled prospectively. Cerebral infarction was diagnosed using magnetic resonance imaging. Results: Of 186 patients, 80 (43%) had infarction. Most infarctions were multiple and located in the cortical areas, basal ganglia and subcortical regions. Independent predictors of infarction at admission included high blood pressure, short illness duration, low Glasgow coma scale and hydrocephalus. Neuroimaging inflammation signs, cerebrospinal fluid analysis abnormalities and pre-existing cardiovascular risks did not predict infarction. In-hospital mortality was higher in TBM with infarction, particularly in those with advanced TBM (stage 3). Conclusion: Baseline parameters of raised intracranial pressure predict cerebral infarction in TBM.

Magnetic resonance imaging findings in central nervous system tuberculosis: A pictorial review

Central nervous system (CNS) tuberculosis is a post-primary form of tuberculosis. It has high mortality and morbidity rates despite early diagnosis and treatment. CNS tuberculosis can manifest as subacute/chronic meningitis, parenchymal tuberculous lesions, and spinal tuberculosis. Hematogenous spread of tuberculous bacilli to the brain results in the development of so called "rich foci" on the pial surface, ependyma, and grey-white matter junction. Rupture of these "rich foci" into the subarachnoid space triggers an intense granulomatous inflammatory reaction. Tuberculous meningitis can manifest as leptomeningitis or pachymeningitis. Intracranial parenchymal tuberculous lesions may present as tuberculoma, tuberculous abscess, cerebritis, rhombencephalitis, and encephalopathy, with atypical presentations not uncommon. Complications of CNS tuberculosis encompass hydrocephalus, syrinx formation, vasculitis, infarcts, neuritis, and enduring neurological deficits. Post-contrast 3D fluid-attenuated inversion recovery (FLAIR) and post-contrast T1 spin-echo sequences excel in detecting tuberculous meningitis compared to other conventional magnetic resonance imaging (MRI) sequences. In proton magnetic resonance spectroscopy (PMRS), the presence of a lipid peak at 1.3 ppm is indicative of tuberculous lesions. Magnetization transfer (MT) imaging enhances the detection of tuberculous lesions, as the magnetization transfer ratio (MTR) of tuberculous pathologies, owing to their high lipid content, is lower than that in bacterial or fungal pathologies and higher than that in viral pathologies. This review article delves into the various typical and atypical imaging presentations of CNS tuberculosis in MRI, along with recent advances in imaging techniques.

MRI advances in the imaging diagnosis of tuberculous meningitis: opportunities and innovations

Tuberculous meningitis (TBM) is not only one of the most fatal forms of tuberculosis, but also a major public health concern worldwide, presenting grave clinical challenges due to its nonspecific symptoms and the urgent need for timely intervention. The severity and the rapid progression of TBM underscore the necessity of early and accurate diagnosis to prevent irreversible neurological deficits and reduce mortality rates. Traditional diagnostic methods, reliant primarily on clinical findings and cerebrospinal fluid analysis, often falter in delivering timely and conclusive results. Moreover, such methods struggle to distinguish TBM from other forms of neuroinfections, making it critical to seek advanced diagnostic solutions. Against this backdrop, magnetic resonance imaging (MRI) has emerged as an indispensable modality in diagnostics, owing to its unique advantages. This review provides an overview of the advancements in MRI technology, specifically emphasizing its crucial applications in the early detection and identification of complex pathological changes in TBM. The integration of artificial intelligence (AI) has further enhanced the transformative impact of MRI on TBM diagnostic imaging. When these cutting-edge technologies synergize with deep learning algorithms, they substantially improve diagnostic precision and efficiency. Currently, the field of TBM imaging diagnosis is undergoing a phase of technological amalgamation. The melding of MRI and AI technologies unquestionably signals new opportunities in this specialized area.

Intracranial vessel wall magnetic resonance imaging features of infectious vasculitis

Vasculitis is a complication of several infectious diseases affecting the central nervous system, which may result in ischemic and/or hemorrhagic stroke, transient ischemic attack, and aneurysm formation. The infectious agent may directly infect the endothelium, causing vasculitis, or indirectly affect the vessel wall through an immunological mechanism. The clinical manifestations of these complications usually overlap with those of non-infectious vascular diseases, making diagnosis challenging. Intracranial vessel wall magnetic resonance imaging (VWI) enables the evaluation of the vessel wall and the diseases that affect it, providing diagnostic data beyond luminal changes and enabling the identification of inflammatory changes in cerebral vasculitis. This technique demonstrates concentric vessel wall thickening and gadolinium enhancement, associated or not with adjacent brain parenchymal enhancement, in patients with vasculitis of any origin. It permits the detection of early alterations, even before a stenosis occurs. In this article, we review the intracranial vessel wall imaging features of infectious vasculitis of bacterial, viral, and fungal etiologies.

MRI-based radiomics signature for identification of invisible basal cisterns changes in tuberculous meningitis: a preliminary multicenter study

OBJECTIVE

To develop and evaluate a radiomics signature based on magnetic resonance imaging (MRI) from multicenter datasets for identification of invisible basal cisterns changes in tuberculous meningitis (TBM) patients.

METHODS

Our retrospective study enrolled 184 TBM patients and 187 non-TBM controls from 3 Chinese hospitals (training dataset, 158 TBM patients and 159 non-TBM controls; testing dataset, 26 TBM patients and 28 non-TBM controls). nnU-Net was used to segment basal cisterns in fluid-attenuated inversion recovery (FLAIR) images. Subsequently, radiomics features were extracted from segmented basal cisterns in FLAIR and T2-weighted (T2W) images. Feature selection was carried out in three steps. Support vector machine (SVM) and logistic regression (LR) classifiers were applied to construct the radiomics signature to directly identify basal cisterns changes in TBM patients. Finally, the diagnostic performance was evaluated by the receiver operating characteristic (ROC) curve analysis, calibration curve, and decision curve analysis (DCA).

RESULTS

The segmentation model achieved the mean Dice coefficients of 0.920 and 0.727 in the training and testing datasets, respectively. The SVM model with 7 T2WI-based radiomics features achieved best discrimination capability for basal cisterns changes with an AUC of 0.796 (95% CI, 0.744-0.847) in the training dataset, and an AUC of 0.751 (95% CI, 0.617-0.886) with good calibration in the testing dataset. DCA confirmed its clinical usefulness.

CONCLUSION

The T2WI-based radiomics signature combined with deep learning segmentation could provide a fully automatic, non-invasive tool to identify invisible changes of basal cisterns, which has the potential to assist in the diagnosis of TBM.

KEY POINTS

• The T2WI-based radiomics signature was useful for identifying invisible basal cistern changes in TBM. • The nnU-Net model achieved acceptable results for the auto-segmentation of basal cisterns. • Combining radiomics and deep learning segmentation provided an automatic, non-invasive approach to assist in the diagnosis of TBM.

High-resolution intracranial vessel wall imaging in cerebral viral infections evaluations

Purpose

Vascular complications can be seen in various viral CNS infections. Variable neuro-imaging findings have been described in the literature elucidating the parenchymal changes with vascular involvement. Vessel wall imaging (VWI) can help to detect these vascular involvements. We aimed to describe the role and usefulness of VWI in the evaluation of various viral CNS infections.

Methods

In this prospective study, we included 15 cases of various diagnosed viral CNS infections (varicella, HIV encephalopathy, HSV encephalitis, Japanese encephalitis, dengue, COVID-19). VWI and time-of-flight MR angiography (TOF MRA) were included in imaging protocol. All cases were evaluated for the presence of cerebral parenchymal changes, vascular enhancement, and vascular stenosis.

Results

We found infarctions in all 5 cases of varicella, 1 case of HIV encephalopathy, and 1 case of COVID-19 encephalopathy. All these cases also showed vascular enhancement and stenosis on VWI. The rest of the cases, including 1 case of HIV encephalopathy, 3 cases of herpes encephalitis, 2 cases of dengue, and 2 cases of Japanese encephalitis did not have any vascular complication, and also did not show vascular enhancement or stenosis.

Conclusion

VWI can be useful in the detection of vascular involvement in various viral infections of CNS which show a relatively higher cerebrovascular complication rate like varicella, HIV encephalopathy, and COVID-19. However, VWI may not be useful in the routine evaluation of other viral infections like herpes, dengue, and Japanese encephalitis, which have a very low rate of cerebrovascular complication rate.

MR vessel wall imaging in cerebral bacterial and fungal infections

Purpose

Central nervous system (CNS) bacterial and fungal infections can cause secondary vasculitis which worsens the prognosis due to development of complications like infarctions or hemorrhages. In this prospective study, we aim to study intracranial vessel wall imaging findings in bacterial and fungal infections.

Methods

We included 12 cases of nontubercular bacterial and fungal CNS infections each, in whom definitive microbiological diagnosis could be made. High-resolution vessel wall imaging (VWI) and time of flight MR angiography (TOF MRA) were incorporated in the routine imaging protocol. All cases were evaluated for the presence of vascular enhancement, pattern of enhancement, and stenosis on VWI. Statistical analysis was done to evaluate association between findings of vessel wall imaging and infarctions.

Results

We found infarctions in 5 out of 12 cases (41.7%) of the bacterial group and 7 out of 12 cases (58.3%) of the fungal group. Vessel wall enhancement was seen in 5 cases (41.7%) of the bacterial group and 9 cases (75%) of the fungal group. There was a significant association between infarctions and vessel wall enhancement in the fungal group. However, pattern of enhancement or stenosis on VWI was not significantly associated with presence of infarction. VWI detected more cases of vascular involvement than TOF MRA.

Conclusion

Secondary infectious vasculitis in bacterial and fungal infections can be detected by VWI, which can play an important role in better patient management as detection of vascular involvement can prompt early treatment to prevent complications like infarctions or hemorrhages.