diffusion tensor imaging

Carpal tunnel syndrome (CTS) is a common peripheral nerve entrapment disorder that is diagnosed using clinical signs and symptoms and confirmed via nerve conduction studies (NCSs). While NCS is a semi-invasive procedure, magnetic resonance imaging (MRI) is a non-invasive diagnostic tool that detects macroscopic nerve abnormalities and evaluates a patient's surgical or medication treatment options. This study assessed magnetic resonance neurography (MRN)’s diagnostic and grading value by comparing it to electrodiagnostic studies in patients with CTS and healthy individuals. This was a cross-sectional study on 27 wrists with CTS and 27 healthy wrists. After history taking and physical examination, we employed an NCS to confirm and determine the severity of CTS, then MRN and diffusion tensor imaging (DTI) were used to calculate apparent diffusion coefficient (ADC), fractional anisotropy (FA), and cross-sectional area (CSA). 18 patients with CTS (27 median nerves) and 15 healthy controls (27 median nerves) were evaluated. The mean FA in the CTS group was significantly lower (0.38 ± 0.05 vs. 0.45 ± 0.06, P < 0.001). The mean CSA and ADC were higher in patients with CTS but not statistically significant. FA’s diagnostic cut-off was 0.42, with a sensitivity of 70.4% and a specificity of 63%. MRN with DTI can be an effective and non-invasive diagnostic technique for the detection of CTS. The FA measure demonstrated adequate sensitivity and specificity for differentiating patients with CTS from healthy individuals.

The importance of diffusion in prostate cancer (PCa) diagnosis has been widely proven. Several studies investigated diffusion models in PCa diagnosis.

This systematic review and meta?analysis study was performed to evaluate the ability of three diffusion models to diagnose PCa from the scientific electronic databases Embase, PubMed, Scopus, and Web of Science (ISI) for the period up to March 2022 to identify all relevant articles.

Eighteen studies were included in the systematic review section (7 diffusion kurtosis imaging [DKI] studies, 4 diffusion tensor imaging [DTI] studies, 4 intravoxel incoherent motion [IVIM] studies, and 3 IVIM?DKI studies). Pooled sensitivity, specificity, accuracy, and summary area under each diffusion model’scurve (AUC) and 95% confidence intervals (CIs) were calculated. The pooled accuracy and 95% CI on detection (differentiation of tumor from normal tissue and benign prostatic hyperplasia/prostatitis) were obtained for apparent diffusion coefficient (ADC) at 87.97% (84.56%–91.38%) for DKI parameters (Gaussian diffusion [DK] 87.94% [78.71%–97.16%] and deviation from Gaussian diffusion[K] 86.84% [81.83%–91.85%]) and IVIM parameters (true molecular diffusion [DIVIM] 81.73% [72.54%–90.91%], perfusion?related diffusion [D*] 65% [48.47%–81.53%] and perfusion fraction [f] 80.36% [64.23%–96.48%]). The AUC values and 95% CI in the detection of PCa were obtained for ADC at 0.95 (0.92–0.97), for DKI parameters (DK 0.94 [0.89–0.99] and K 0.93 [0.90–0.96]) and for IVIM parameters (DIVIM 0.85 [0.80–0.91], D* 0.60 [0.43–0.77] and f 0.73 [0.63–0.84]). Two studies showed that the DTI accuracy values were 97.34% and 85%. For IVIM–kurtosis model in PCa detection, two studies stated that the DIVIM?K and KIVIM?K accuracy values were 85% and 84.44% (the pooled accuracy; 84.64% with 95% CI 75.78%–93.50%), and 72.50% and 71.11% (the pooled accuracy, 72.10% with 95% CI 64.73%–79.48%), respectively.

Our findings showed that among the DKI, IVIM, and ADC parameters,it seems that ADC, Dk, DIVIM, and K are the most important, which can be used as an indicator to distinguish PCa from normal tissue. The DKI model probably has a higher ability to detect PCa from normal tissue than the IVIM model. DKI probably has the same diagnostic performance in PCa detection and grading compared to diffusion?weighted imaging and ADC.

Disruption in the descending pathways may lead to gait impairments in Cerebral Palsy (CP) children. Though, the mechanisms behind walking problems have not been completely understood.

We aimed to define the relationship between the structure of the corticoreticular tract (CRT) and walking capacity in children with CP.

This is a retrospective, observational, and cross-sectional study. Twenty-six children with CP between 4 to 15 years old participated. Also, we used existed data of healthy children aged 4 to 15 years old. CRT structure was characterized using diffusion tensor imaging (DTI). The DTI parameters extracted to quantify CRT structure included: fractional anisotropy (FA), mean (MD), axial (AD), and radial (RD) diffusivity. Balance and walking capacity was evaluated using popular clinical measures, including the Berg balance scale (BBS), Timed-Up-and-Go (TUG; balance and mobility), six-minute walk test (6 MWT; gait endurance), and 10-meter walk Test (10 MWT; gait speed).

There are significant differences between MD, AD, and RD in CP and healthy groups. Brain injury leads to various patterns of the CRT structure in children with CP. In the CP group with abnormal CRT patterns, DTI parameters of the more affected CRT are significantly correlated with walking balance, speed, and endurance measures. 

Considering the high inter-subject variability, the variability of CRT patterns is vital for determining the nature of changes in CRT structure, their relationship with gait impairment, and understanding the underlying mechanisms of movement disorders. This information is also important for the development or prescription of an effective rehabilitation target for individualizing treatment.

 Cerebral small vessel disease (CSVD) is a chronic disorder affecting small vessels within the brain, increasing the risk of stroke in patients with chronic kidney disease (CKD). Diffusion tensor imaging (DTI) is a newer quantitative method for diagnosing CSVD at an early stage of pathogenesis.

 This study compares various DTI parameters in multiple white matter tracts of the brain in CKD patients undergoing maintenance hemodialysis with normal controls in the Indian population using the volume of interest (VOI) method. Additionally, it correlates these DTI parameters with each other at different locations to gain insights into the pathogenesis of CSVD.

 After obtaining institutional ethics approval, a cross-sectional study was conducted at a tertiary care hospital over one year (June 2022 to May 2023). The study comprised seventy-five patients in the hemodialysis group and twenty-five controls. All participants underwent MRI brain examinations on a 3 Tesla MRI scanner, and the four DTI parameters - fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD) - were reviewed for nine white matter tracts to evaluate statistical differences and correlations.

 Fractional anisotropy was significantly decreased at anterior locations – corpus callosum genu (P = 0. 357 × 10-7), right anterior corona radiata (P = 0.001), and left anterior corona radiata (P = 0.45 × 10-5). In these locations, FA negatively correlated with RD (R = -0.7904, P < 0.00001), and RD was also significantly increased. Axial diffusivity was significantly increased at posterior locations in the corpus callosum splenium (P = 0.108 × 10-5) and left posterior corona radiata (P = 0.244 × 10-5). However, none of the four DTI parameters showed significant differences between hemodialysis patients and the control group for the subset of patients with normal routine brain MRI features. The intraclass correlation coefficients (ICCs) were high for all four DTI parameters for both patients (0.78 to 0.85) and controls (0.82 to 0.89).

 This study on CKD patients undergoing maintenance hemodialysis reveals significant differences in some DTI parameters in widespread white matter tracts of the brain using the VOI method, with acceptable to excellent interobserver agreement.

Diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI) present the ability to selectively protect functional regions and fiber tracts of the brain when brain tumors are treated with radiotherapy. This study aimed to assess whether the incorporation of fMRI and DTI data into the radiation treatment planning process of brain tumors could prevent the neurological parts of the brain from high doses of radiation. In this investigational theoretical study, the fMRI and DTI data were obtained from eight glioma patients. This patient-specific fMRI and DTI data were attained based on tumor location, the patient’s general conditions, and the importance of the functional and fiber tract areas. The functional regions, fiber tracts, anatomical organs at risk, and the tumor were contoured for radiation treatment planning. Finally, the radiation treatment planning with and without fMRI & DTI information was obtained and compared. The mean dose to the functional areas and the maximum doses were reduced by 25.36% and 18.57% on fMRI & DTI plans compared with the anatomical plans. In addition, 15.59% and 20.84% reductions were achieved in the mean and maximum doses of the fiber tracts, respectively.  This study demonstrated the feasibility of using fMRI and DTI data in radiation treatment planning to maximize radiation protection of the functional cortex and fiber tracts. The mean and maximum doses significantly decreased to neurologically relevant brain regions, resulting in reducing the neuro-cognitive complications and improving the patient’s quality of life.

There are limited data on the possible association between conventional and advanced magnetic resonance imaging (MRI) findings and cognitive function in patients with multiple sclerosis (MS). Therefore, this systematic review and meta-analysis aimed to explore the correlation between MRI-derived metrics and cognitive tests in patients with MS. An electronic literature search of the PubMed, Web of Sciences, Embase, and Scopus databases was performed to identify related studies. The correlation coefficients of the MRI indices and cognitive tests were pooled. Thirteen studies were selected for inclusion of 824 patients diagnosed with MS. Most evaluated patients (60.44%) had relapsing-remitting MS (RRMS). The Paced Auditory Serial Addition Test (PASAT-3), Brief Visuospatial Memory Test (BVMT), and Symbol Digit Modalities Test (SDMT) were inversely correlated with the mean diffusivity (MD) of the brain with pooled correlation coefficient of -0.225, -0.361, and -0.438, respectively (P<0.0001). The SDMT test positively correlated with fractional anisotropy (FA) with a correlation coefficient of 0.351 (P<0.0001) and inversely correlated with T2 lesion volume with a correlation coefficient of -0.367 (P<0.0001). In the case of other tests, there was low number of studies with significant correlations being reported. We found significant correlations between some neuropsychological tests and MRI findings in patients with MS. Brain atrophy might disrupt the process of correct registration between anatomical and MRI diffusion scans. However, we did not have enough studies with exactly matched anatomical areas to evaluate correlations and we recommend that histological validation of diffusion tensor imaging (DTI) findings for brain atrophy is needed as a basis for picture processing procedures and correlation with cognition status.

 Most brain gliomas are high-grade and likely to spread locally. Consequently, these patients commonly have a poor prognosis. Accurate identification of the malignancy grade of brain glioma before treatment is of great clinical significance.

 This study aimed to explore the correlation of diffusion tensor imaging (DTI) parameters, fractional anisotropy (FA), and apparent diffusion coefficient (ADC) with the pathological grade of brain glioma and expression of vascular endothelial growth factor (VEGF) and Ki-67.

 A total of 116 patients were selected for this study from January 2018 to December 2019. All the participants underwent magnetic resonance imaging (MRI) and DTI before surgery, and the FA and ADC values were measured for the regions of interest. Surgically resected tumor specimens were collected for immunohistochemical assay. Finally, the FA and ADC values and positive expression rates of VEGF and Ki-67 were compared.

 A significantly higher FA, besides the positive expression of VEGF and Ki-67, was reported in the high-grade group, whereas a lower ADC was found in this group compared to the low-grade group (P < 0.05). Areas of normal white matter and peritumoral edema had higher FA values, whereas lower ADCs were measured in these areas compared to the cerebrospinal fluid (P < 0.05). The FA of tumor parenchymal area was positively correlated with the World Health Organization (WHO) WHO class of tumors (r = 0.588, P = 0.028), and the expression of VEGF and Ki-67 was positively correlated with the WHO grade (r = 0.843, P = 0.002 and r = 0.743, P = 0.006, respectively). The FA of tumor parenchymal area was positively correlated with the expression of VEGF and Ki-67 (r = 0.654, P = 0.008 and r = 0.567, P = 0.012, respectively). However, the ADC of tumor parenchymal area was not significantly correlated with the WHO grade, VEGF expression, or Ki-67 expression (r = 0.143, P = 0.156, r = 0.232, P = 0.116, and r = 0.054, P = 0.179, respectively).

 The FA value, as a DTI parameter, is valuable for assessing the malignancy grade of tumor cells and can provide a proper reference for formulating treatment regimens for brain gliomas.

The methods to detect brain activation with functional MRI (fMRI), and MRI provide a way to measure the anatomical connections which enable lightning-fast communication among neurons that specialize in different kinds of brain functions. Diffusion tensor imaging (DTI) can measure the direction of bundles of the axonal fibers which are all aligned. Besides mapping white matter fiber tracts, these methods can enable us to detect and characterize white matter disorders in diseases. The objective of this narrative review is to overview current knowledge concerning DTI as one of the
prominent popular MRI techniques that provide a planned tool for comprehensive, noninvasive, functional anatomy mapping of the human brain in both research and practical field. This review summarizes the DTI development in recent years concerning the specificity and utility of this technique in brain surgery.

Methods and Materials/Patients:

 The significance of mapping the structure of white matter tracts, constructively the brain’s wiring by visualization and characterization of white matter fasciculi in two and three dimensions enables us to profound how different brain regions are connected and how diseases affect white matter and cause neurological problems. And we noted that while DTI proposes a potent tool to study and visualize white matter, it suffers from inherent artifacts and limitations. Additionally, some materials about the origin of the DTI signal and unique information on white matter and 3D visualization of neuronal tracts have been raised.

This article focuses on DTI modality and its computational techniques, and investigates significant considerations in this regard. Moreover, an inspection of the white matter structure and integrity of normal and diseased brains (e.g. multiple sclerosis, stroke, aging, dementia, schizophrenia, etc.) have been raised as a clinical application of tractography.

The utilization of advances in diffusion-tensor (DT) imaging techniques considerably enables us to map the white matter tractography (WMT) in the normal brain. These techniques impress the operative decision in a surgical operation, especially concerning cerebral neoplasms. Also, it is possible to judge with the assistance of DTI in each subject.

Diffusion Tensor Imaging (DTI)-based tractography can help us visualize the spatial relation of fiber tracts to brain lesions. Several factors may interfere with the procedure of diffusion-based tractography, especially in brain tumors. The current study aims to discuss several solutions to improve the procedure of fiber reconstruction adjacent to or inside brain lesions. Illustrative cases are also presented.

Methods and Materials/Patients

 The paper is a narrative review of methods that can improve DTI-based fiber reconstruction in the area of brain tumors. To provide up-to-date information, we briefly reviewed related articles extracted from Google Scholar, Medline, and PubMed.

We proposed five techniques to improve fiber reconstruction. Technique 1 is a very low Fractional Anisotropy (FA) application. Technique 2 includes resampling techniques, such as q-ball and High Angular Resolution Diffusion Imaging (HARDI). Technique 3 is the reconstruction of fiber tracts by defining the separated Region of Interest (ROIs). Technique 4 explains the selection of the ROIs according to functional Magnetic Resonance Imaging (fMRI) since the anatomical configuration is distorted by neoplasm. Technique 5 consists of using unprocessed images for preoperative planning and correlation with the clinical situation.

DTI tractography is highly sensitive to noise and artifacts. The application of tractography techniques can improve fiber imaging in the area of brain tumors and edema.

Fibromyalgia is recognized as a chronic pain syndrome. Widespread pain is a common symptom in fibromyalgia, indicating a potential dysfunction in the processing of painful sensations in the central nervous system.

This study aimed to investigate changes in the severity of clinical symptoms in fibromyalgia patients and to evaluate the apparent diffusion coefficients and metabolites in the brain of these patients.

 

This cross-sectional study included 28 female outpatients with complaints of widespread pain, who were diagnosed with fibromyalgia syndrome. Magnetic resonance imaging, magnetic resonance spectroscopy, and diffusion tensor examinations were applied to evaluate patients diagnosed with fibromyalgia before treatment.

The mean age of the patients included in this study was 39.1 ± 8.6 years (range, 24 - 55 years). A statistically significant strong positive correlation was found between the scores of the visual analog scale and the fibromyalgia impact questionnaire. Besides, significant associations were found between the scores of the visual analog scale and fibromyalgia impact questionnaire and the results of fractional anisotropy, apparent diffusion coefficient, and peak values of some metabolites in spectroscopy.

The results of this study suggest that metabolites play an inhibitory or excitatory role in the central pain mechanisms of fibromyalgia as a chronic pain syndrome.

Recently, it has been proven that assuming the Gaussian model in DTImethod is inappropriate for propagation in a complex substrate such as human braintissue. High Angular Resolution Diffusion Imaging (HARDI) (or so called q-ball imaging)is known as a model free method that allows to more accurately detect changes in diffusionwith different orientations. In this study, after finding the best angle threshold at the OpticRadiation (OR) level, the length and number of reconstructed nerve fibers in this anglewere measured using q-ball imaging and were compared with DTI. Tractographs of q-ball images from the human brains of 10healthy volunteers (30 to 50 years old) were studied using a 3-Tesla scanner. 64 directionsof diffusion encoding in two b-values (1000 and 2000 s/mm2), were used for q-ballimaging and in routine b-value of 1000 s/mm2 for DTI. The tractographs were comparedat the OR level with the tractography based on q-ball and DTI images. The results wereanalyzed using t-test. The angle threshold for tractography was selected at 45 degrees bycomparing the tractographs in 13 angles. Consequently, the number and length of nerve fibers of OR, measured usingthe q-ball imaging, were significantly higher than those using the DTI. Finally, the betterquality of the tractographs as well as the analyzed quantities, are indicators of larger signalto-noise ratio in q-ball imaging and indicate that q-ball imaging compared to DTI plays animportant role in the development of brain nerve mapping.

Brain injury in premature infants (BIPI) is a severe brain damage in premature infants, resulting in a series of neurological sequelae. Diffusion tensor imaging (DTI), as a magnetic resonance imaging (MRI) technique, is more widely used for premature infants. It is of paramount importance to improve the early diagnosis, treatment, and intervention for this population by using DTI. There are few reports on the application of DTI for the evaluation of BIPI in low-birth-weight (LBW) and very-low-birth-weight (VLBW) infants.

To analyze the clinical characteristics of BIPI in LBW and VLBW infants and to explore the value of MRI-based DTI in the evaluation of BIPI in LBW infants.

This prospective study was conducted on 31 cases of BIPI (16 LBW and 15 VLBW infants) and 20 normal control premature infants, undergoing MRI-based DTI at the postmenstrual age (PMA). Differences in fractional anisotropy (FA) and apparent diffusion coefficient (ADC) between the BIPI and control groups and also between the LBW and VLBW groups with BIPI were analyzed. Also, differences with normal controls in terms of the FA and ADC values were investigated in different brain regions.

The FA values in the central white matter of the frontal lobe, central white matter of the occipital lobe, centrum semiovale, posterior limb of the internal capsule (PLIC), and ventral thalamus were significantly lower in the BIPI group as compared to the control group (P < 0.05). The ADCs were lower in the BIPI group compared to the control group, and there was a significant difference (P < 0.05). Comparison of FA and ADC values in the central white matter of the frontal lobe, central white matter of the occipital lobe, centrum semiovale, PLIC, and ventral thalamus did not show any significant differences between the LBW and VLBW groups with BIPI (P > 0.05).

The FA and ADC values of DTI can be used for the quantitative evaluation of BIPI in LBW and VLBW infants. The FA value was found to be more accurate than the ADC. Overall, different FA values in different brain areas reflect differences in the brain development of normal premature infants.

Obstructive nephropathy is a common clinical disease.

To explore the value of diffusion tensor imaging (DTI) in obstructive nephropathy.

Forty healthy Sprague-Dawley (SD) rats were examined in this study. Thirty-two animals underwent complete obstruction of the left ureter, while eight animals underwent a sham surgery. Magnetic resonance imaging (MRI) was performed before surgery and within different intervals after surgery. Eight rats from the experimental group and two rats from the sham group were used in each interval. Following MRI, the animals were sacrificed and sent for medical examinations. The scanning sequences included positioning, transverse T2-weighted (T2W), coronal, and coronal DTI sequences. Image postprocessing was performed after DTI to measure DTI parameters, including apparent diffusion coefficient (ADC) and fractional anisotropy (FA), and to reconstruct DTI fiber traces. One-way analysis of variance was used to compare the parameters between the cortex and medulla and between different intervals.

The fiber tracing showed that the obstructed renal fiber bundles were sparse and disordered. The ADC and FA values of the renal cortex, extrarenal medulla, and inner medulla decreased with prolonged hydrops and were negatively correlated with the expression of alpha-smooth muscle actin (α-SMA) and the renal tubulointerstitial lesion grade (r < 0, P < 0.001). Comparison of the cortex, extrarenal medulla, and inner medulla showed the following trends for the ADC and FA values: cortex > extrarenal medulla > inner medulla and cortex < extrarenal medulla < inner medulla, respectively.

DTI in obstructive nephropathy not only can reflect the degree of renal interstitial fibrosis and accurately indicate the renal function, but also can provide information regarding renal blood perfusion, water metabolism, and ultrastructural changes.

Traumatic brain injury (TBI) seriously affects the quality of life of patients. The present study evaluated the role of diffusion tensor imaging (DTI) combined with Neuron-Specific Enolase (NSE) and S100 calcium-bindingproteinB (S100B)protein in predicting the prognosis of moderate and severe TBI.

The TBI patients were divided into moderate TBI (TBIm) and severe TBI (TBIs) groups according to the Glasgow Coma Scale (GCS) after admission. The patients were then divided into good and poor prognosis groups according to the Glasgow Outcome Scale (GOS); moreover, their follow-ups were recorded at 3 and 6 months after injury. This study also included 65 healthy individuals with matched age and gender as the control group. The fractional anisotropy (FA) values of DTI, serum neuron-specific enolase (NSE), and S100B protein levels were detected in this study. The data were analyzed in SPSS software (version 22.0) to evaluate the role of DTI combined with NSE and S100B protein in predicting the prognosis in TBIm and TBIs.

After TBI, the FA values of DTI in the TBI group were lower than those in the control group (P<0.05); moreover, the serum NSE and S100B values in the TBI group were higher than those in the control group (P<0.05). In the TBIm patients, the FA values of the corpus callosum in the good prognosis group werehigher than that in the poor prognosis group (P<0.05); however, there was no significant difference between the two groups regarding the FA values of the internal capsule and the cerebral peduncle (P>0.05). The serum levels of NSE and S100B in the good prognosis group were significantly lower than those in the poor prognosis group (P<0.05). In the TBIs patients, the FA value of all areas in the good prognosis group was significantly higher than that in the poor prognosis group (P<0.05). However, there was no significant difference between the two prognosis groups regarding the serum levels of NSE and S100B (P>0.05).

Although DTI combined with NSE and S100B protein can effectively predict the prognosis of patients with moderate and severe TBI in the early stages, various other measures have been used in the studies to predict the prognosis of TBI patients. Accordingly,comparison with other measures is essential in further studies.

 Parkinson's disease (PD) is a chronic and progressive neurodegenerative disease that affects the dopamine-containing neurons. In this study, the role of the Diffusion Tensor imaging (DTI) method was investigated in the detection of PD.

 The purpose of this study was to investigate the microstructural damage of the brain's white matter in PD using a non-invasive DTI technique.

 Twenty patients with PD were studied with comprehensive clinical assessments and DTI data. Also, 10 normal subjects were investigated. Fractional anisotropic (FA) and mean diffusivity (MD) values were calculated by drawing region of interest (ROI) on eight distinctive areas of the brain.

 The level of FA and MD in substantia nigra (SN) was significantly different between the PD and healthy control (HC) groups. Also, differences were found in DTI parameters between PD and HC groups in some regions, such as genu, anterior limb of internal capsule (ALIC), splenium, and putamen.

 To summarize, DTI as a non-invasive method can be useful in the detection of Parkinson's disease.

Multiple Sclerosis (MS), distinguished by aggravating the function of central nervous system because of inflammatory demyelination. The most sensitive method for MS diagnosis is Magnetic resonance imaging (MRI). To distinguish inactive and active MS lesions, contrast-enhanced T1-weighted imaging (CE T1WI) is being used as a gold standard. There are some contraindications in gadolinium based contrast agents (GBCAs) usage. Moreover, diffusion-weighted imaging (DWI) can discover diffusion changes involved inflammatory lesions.

The current research aims at investigating if typical DWI (3 directional) and 12 directional DWI could be a substitute for CE T1WI in order to show active lesions of MS.

In this cross-sectional study, 138 patients with CNS symptoms were examined. For all patients, along with CE T1WI, 3 & 12 directional DWI were performed. Intraclass correlation coefficient (ICC), receiver operating characteristic (ROC), the sensitivity versus specificity plot and the area under the curve (AUC) were calculated.

There was a contrast enhancement in CE T1WI for 114 patients (82.6%); in addition, hyper-intense lesions on DWI 3 and DWI 12 were shown in 107 (77.5%) and 117 patients (84.7%) in order. Sensitivity, specificity and AUC were 94.7%, 62.5% and 84% for DWI 12. Moreover, the results were 86%, 62.5 and 79% for the sensitivity, specificity and AUC for DWI 3 respectively.

In spite of lower sensitivity of 12 directional DWI compared to CE T1WI, it could be used as a diagnostic sequence in differentiating enhanced lesions from non-enhanced ones when CE-MRI is a worry.

Tuberculous meningitis (TBM) is a highly devastating manifestation of tuberculosis. So far, the major role of the neuroradiology in the management of TBM has been restricted to diagnosis and follow-up of the complications. This study aimed to establish the use of advanced magnetic resonance imaging (MRI) techniques in the early detection of sequelae of TBM like vasculitis and hydrocephalous.

In this prospective observational study, 30 patients of TBM were recruited during 1 year at a tertiary care health center of northern India and their serial MRI brain was done. Patients were between 18 and 45 years of age.

Basal/Sylvian exudates were seen in 90% of patients, hydrocephalus was found in 30% of patients and infarcts were found in 27% of patients. No significant difference was found between the mean, mean diffusivity (MD), and mean fractional anisotropy (FA) in frontal white matter, basal ganglia, thalamus, pons of cases and controls. A significant difference was seen between mean cerebral blood flow (CBF) in the region of basal ganglia of cases and controls (P < 0.05). No significant difference was seen between mean CBF in frontal white matter, thalamus of cases and controls. Diffusion tensor imaging parameters, MD, and FA were abnormal in the region of infarcts (basal ganglia) in three patients in the first scan, the parameters normalized in one patient (late subacute to chronic infarct in the first scan), and they remained abnormal in two patients.

Advanced MRI techniques (magnetization transfer imaging) is helpful in visualizing hyperintense thickened meninges in basal cisterns and Sylvian fissures on pre-contrast imaging, and in identifying reduced CBF in the region of basal ganglia.