Differentiation of multiple sclerosis lesions and low-grade brain tumors on MRS data: machine learning approaches.

Some multiple sclerosis (MS) lesions may have great similarities with neoplastic brain lesions in magnetic resonance (MR) imaging and thus wrong diagnoses may occur. In this study, differentiation of MS and low-grade brain tumors was performed with computer-aided diagnosis (CAD) methods by magnetic resonance spectroscopy (MRS) data. MRS data belonging to 51 MS and 39 low-grade brain tumor patients were obtained. The feature extraction from MRS data was performed by the help of peak integration (PI) and full spectra (FS) methods and the most significant features were identified. For the classification step, artificial neural network (ANN), support vector machine (SVM), and linear discriminant analysis (LDA) methods were used and the differentiation between MS and brain tumor was performed automatically. Examining the results, one can conclude that data which belong to MS and low-grade brain tumor cases were automatically differentiated from each other with the help of ANN with 100% accuracy, 100% sensitivity, and 100% specificity. Using of MR spectroscopy and artificial intelligence methods may be useful as a complementary imaging technique to MR imaging in the differentiation of MS lesions and low-grade brain tumors.

Relationships of Language Lateralization with Diffusion Tensor Imaging Metrics of Corpus Callosum, Tumor Grade, and Tumors Distance to Language-Eloquent Areas in Glial Neoplasms.

PURPOSE: The aim of the study was to search relationships between language lateralization and corpus callosum (CC) connectivity, tumor grade, and tumors distance to language-eloquent areas in glial neoplasms. MATERIALS AND METHODS: The functional magnetic resonance imaging and CC diffusion tensor imaging (DTI) metrics of 42 patients with glial neoplasm were evaluated for relationships of language lateralization (left, right, and bilateral) with CC DTI metrics (tracts number, voxel, volume, length, fractional anisotropy [FA], and apparent diffusion coefficient), tumor grade, and tumors distance to language-eloquent areas and relationships of CC DTI metrics with tumor grade. Kruskal-Wallis, Mann-Whitney U, and χ tests were used. All were repeated in 26 patients with left hemispheric masses. RESULTS: In glial masses, language bilateralism was more common than normal population and more pronounced in low grade than high grade. In right lateralism and bilateralism, tumor settlement nearby language-eloquent areas was more common. In the left lateralism, highest CC tract number, higher tumor grade, and more remote tumor settlements were noted. There was no relationship between CC DTI metrics and tumor grade but increase in CC tracts number and FA with increasing tumor grade. CONCLUSIONS: Increased bilateralism in glial masses than normal population and in low grade tumors than high grade and increased nearby tumor settlement in right lateralism and bilateralism support interhemispheric reorganization and plasticity. This is more pronounced in low grade because of higher life span. Highest CC tract number, higher tumor grade, and more remote tumor settlement in left lateralized group suggest intact CC integrity with limited hemispheric destruction. Increasing CC tracts number and FA with increasing tumor grade support preserved CC integrity in the shorter life span of high-grade tumors.

Normal Pressure Hydrocephalus: Clinical Symptoms, Cerebrospinal Fluid Flow Metrics and White Matter Changes.

PURPOSE: The aim of this study was to investigate correlations between clinical symptoms, cerebrospinal fluid flow metrics, hydrocephalus index, small-vessel disease, and white matter (WM) changes in normal pressure hydrocephalus (NPH). METHODS: Aquaductal stroke volumes (ASVs), Z Evans index, Fazekas grading (FG), and diffusion tensor imaging measurements from WM bundles of 37 patients with NPH were retrospectively evaluated. Mann-Whitney U test between clinical symptoms and other variables and Spearman ρ correlations for relationships between variables and Kruskal-Wallis to correlate FG with nonclinical variables were used. RESULTS: Patients with NPH had increased ASV (median 53 µL). No correlation was found between Z Evans index and ASV. Three groups of patients with dementia or ataxia or incontinence had increased ASV values than their counterparts without symptoms (55 vs 48.5 µL, 75 vs 47 µL, 64 vs 49.5 µL, respectively). Patients having 2 common symptoms of dementia and ataxia and patients having all 3 symptoms of dementia, ataxia, and incontinence were compared with ASV values of 63.5 versus 78 µL, respectively. Patients with FG 1 had median ASV values of 45 µL; FG 2, 82.5 µL; and FG 3, 59 µL. Patients with dementia had significantly higher apparent diffusion coefficient (ADC) values of corona radiata (CR) on both sides. There were no significant WM changes in patients with ataxia and incontinence. The Z Evans index was positively correlated with ADC values of CR on both sides and genu of corpus callosum. Fazekas grading was found positively correlated with ADC and negatively correlated with FA values of CR. CONCLUSIONS: Patients with NPH, regardless of stages of the diseases, have increased ASV values and could benefit from shunting. Decreasing ASV values of patients with FG 3 comparing with those with FG 2 support the hypothesis of decreasing compliance of brain with aging and increasing severity of small-vessel disease.

MRI findings and utility of DWI in the evaluation of solid parathyroid lesions.

PURPOSE: To evaluate the MRI findings of solid parathyroid lesions and to elaborate on a possible improvement of MRI detection of parathyroid lesions by the use of additional DWI. MATERIALS AND METHODS: MRI and DWI properties of pathologically proven 20 solid parathyroid lesions were retrospectively reviewed. Mean ADC values (b50 + b400 + b800/3) of parathyroid lesions were compared with that of normal appearing thyroid parenchyma (TP), sternocleidomastoid muscle (SCM) and jugulodigastric lymph nodes (JDLN). RESULTS: Of lesions, 4 were parathyroid hyperplasia, 13 parathyroid adenoma and 3 parathyroid adenocarcinoma. All parathyroid lesions were very bright on fat-saturated T2W images. Parathyroid hyperplasia and adenoma were small sized, homogenous, well-defined and low on T1W, high on T2W and avidly enhancing. Parathyroid carcinoma was large sized, ill-defined and very heterogeneous on MRI including DWI. Means ADC values of parathyroid hyperplasia, adenoma, and adenocarcinoma, TP, SCM and JDLN were measured as 2.3 ± 0.14 × 10-3, 1.7 ± 0.45 × 10-3, 1.5 ± 1.48 × 10-3, 0.87 ± 0.40 × 10-3, 0.55 ± 0.21 × 10-3 and 0.96 ± 0.33 × 10-3 mm2/s, respectively. All parathyroid lesions had high diffusion properties comparing other soft tissue structures of head and neck region. By increasing strength (b value) of diffusion tensor on DWI, solid parathyroid lesions still kept their brightness comparing other soft tissue structures of head and neck region because of their high T2 properties. CONCLUSION: Solid parathyroid lesions had higher diffusion properties comparing other soft tissues structures of head and neck region. This feature makes them easily differentiate from nearby structures on fat-saturated T2W and DWI.

Evaluation of CSF flow metrics in patients with communicating hydrocephalus and idiopathic intracranial hypertension.

PURPOSE: To search for CSF dynamics of idiopathic intracranial hypertension (IIH) and communicating hydrocephalus and any correlation between MRI findings, CSF metrics and CSF opening pressure in IIH. MATERIALS AND METHODS: Healthy subjects (30) and subjects with IIH (29) and high-pressure communicating hydrocephalus (43) were enrolled. Nonparametric Kruskal-Wallis test (p = 0.05) was used to compare three groups, Mann-Whitney U test with Bonferroni correction to compare two groups (p = 0.016). Correlation of MRI findings of IIH with CSF metrics and CSF opening pressure was analyzed by Spearman's Rank correlation coefficient (p = 0.05). RESULTS: In IIH, no correlation between MRI findings and aqueductal stroke volume (ASV) but statistically significantly CSF opening pressure in the presence of transverse sinus compression was noted. Comparing with healthy subjects, ASV was nonsignificantly lower and standardized diastolic and sum and difference of systolic and diastolic flow durations were statistically significantly lower. Comparing with hydrocephalus, the width of prepontine cistern (PPC)/the width of aqueductus sylvii (AS) was significantly higher and other CSF metrics with standardized systolic and sum of systolic and diastolic flow durations were significantly lower. In hydrocephalus, ASV and peak velocities were significantly higher. Compared with normal group, PPC/AS and reverse/forward flow duration were significantly lower and other CSF metrics were significantly higher. CONCLUSION: In hydrocephalus, significant increase in ASV and peak velocities were noted. In IIH, CSF opening pressure was statistically significantly high in the presence of transverse sinus compression and standardized diastolic flow durations were statistically significantly short that are probably effects of increased impedance of CSF flow against increased intracranial pressure and unchanged or even decreased intraventricular CSF volume.

Comparison of Delay-Sensitive and Delay-Insensitive Computed Tomography Perfusion Methods in Acute Ischemic Stroke and Their Variability According to Location of Critical Vascular Stenosis.

OBJECTIVE: The aim of this study was to evaluate visual and quantitative differences of delay-sensitive (singular value deconvolution [SVD]) and delay-insensitive (SVD+) computed tomography perfusion (CTP) postprocessing methods in acute ischemic stroke patients and their variability according to location of critical stenosis. METHODS: The CTPs of 45 patients were retrospectively processed with 2 different methods. Comparing with the contralateral normal hemisphere, relative and difference of metrics were calculated (relative cerebral blood volume, relative cerebral blood flow [rCBF], relative mean transite time [rMTT], and difference mean transite time [dMTT]). Patients were categorized into 5 groups according to superiority in visual assessment of penumbra between postprocessing methods. Locations of critical stenosis and their percentages in each group were identified and compared. RESULTS: Differences were formulated as (rCBF/1.4, rMTT × 1.4, dMTT/3.8) SVD = (rCBF, rMTT, dMTT) SVD+. In group 1, penumbra was noted in SVD, whereas pseudohyperperfusion was noted in SVD+. In groups 2 and 3, penumbra was better distinguished in SVD than in SVD+ in decreasing easiness, respectively. In group 4, penumbra assessment was similar in both. In group 5, penumbra was better distinguished in SVD+. Groups 1 and 5 were the groups in which the frequency of critical distal stenosis was 100%. Groups 2, 3, and 4 were the groups having high rates of proximal critical stenosis in decreasing proportions, respectively (90%, 87%, and 77%). CONCLUSIONS: In both CTP methods, the most prominent difference was found in dMTT. Visually, penumbra was better distinguished by SVD in proximal critical stenosis, whereas was better distinguished by SVD+ in distal critical stenosis. In cases having both ipsilateral critical proximal and distal stenoses, penumbra was noted in SVD but pseudohyperperfusion in SVD+. This finding showed that extraction of contrast delay in the SVD+ method might cause false results in cases of ipsilateral critical proximal and distal stenoses.

Investigation of Brain Impairment Using Diffusion-Weighted and Diffusion Tensor Magnetic Resonance Imaging in Experienced Healthy Divers.

BACKGROUND The aim of this study was to understand the changes of decompression illness in healthy divers by comparing diffusion-weighted (DWI) and diffusion tensor MRI findings among healthy professional divers and healthy non-divers with no history of diving. MATERIAL AND METHODS A total of 26 people were recruited in this prospective study: 11 experienced divers with no history of neurological decompression disease (cohort) and 15 healthy non-divers (control). In all study subjects, we evaluated apparent diffusion coefficient (ADC) and type of diffusion tensor metric fractional anisotropy (FA) values of different brain locations (e.g., frontal and parieto-occipital white matter, hippocampus, globus pallidus, putamen, internal capsule, thalamus, cerebral peduncle, pons, cerebellum, and corpus callosum). RESULTS ADC values of hippocampus were high in divers but low in the control group; FA values of globus pallidus and putamen were lower in divers compared to the control group. DWI depicted possible changes due to hypoxia in different regions of the brain. Statistically significant differences in ADC values were found in hypoxia, particularly in the hippocampus (p=0.0002), while FA values in the globus pallidus and putamen were statistically significant (p=0.015 and p=0.031, respectively). We detected forgetfulness in 6 divers and deterioration in fine-motor skills in 2 divers (p=0.002 and p=0.17, respectively). All of them were examined using neuro-psychometric tests. CONCLUSIONS Repeated hyperbaric exposure increases the risk of white matter damage in experienced healthy divers without neurological decompression illness. The hippocampus, globus pallidus, and putamen are the brain areas responsible for memory, learning, navigation, and fine-motor skills and are sensitive to repeated hyperbaric exposure.

Contribution of diffusion-weighted imaging to dynamic contrast-enhanced MRI in the characterization of papillary breast lesions.

Papillary lesions have a broad spectrum of appearances on magnetic resonance imaging (MRI). The purpose of this study was to evaluate whether apparent diffusion coefficient (ADC) values of papillary lesions can be used to characterize lesion as benign or malignant. This retrospective study included 29 papillary lesions. Diagnostic values of dynamic contrast-enhanced MRI (DCE-MRI), DWI-ADC, and DCE-MRI plus DWI-ADC were separately calculated. The malignant papillary lesions (0.744×10-3  mm2 /s) exhibited significantly lower mean ADC values than the benign lesions (1.339×10-3  mm2 /s). Addition of DWI to standard DCE-MRI provided 100% sensitivity. We hypothesized that this combination may prevent unnecessary excisional biopsies.

Spinal cord ischemia after endoscopic ultrasound guided celiac plexus neurolysis: case report and review of the literature.

INTRODUCTION: Endosonography guided celiac plexus neurolysis is efficacious in the management of severe pain due to advanced pancreatic cancer. Although endoscopic ultrasound (EUS) guided celiac neurolysis (CN) is mostly a safer procedure than the percutaneous posterior approach, severe complications such as paraplegia have been reported. CASE REPORT: We describe a patient with advanced adenocarcinoma of the pancreas and severe pain who developed irreversible paraplegia after EUS guided CN. CONCLUSIONS: Endosonography guided celiac plexus neurolysis also might be complicated with paraplegia as already observed with percutaneous approach. The underlying mechanism could not be explained clearly until now. We detected concomitant embolic occlusion of Adamkiewicz and anterior radicularis magna arteries in magnetic resonance angiography. So, this procedure must be considered only for malignancy patients.

Reliability of magnetic resonance imaging versus arthroscopy for the diagnosis and classification of superior glenoid labrum anterior to posterior lesions.

PURPOSE: The physical examination of the shoulder is usually not reliable for the true diagnosis of superior glenoid labrum anterior to posterior (SLAP) lesions. Magnetic resonance imaging (MRI) has been routinely used for the diagnosis. This prospective study investigates the radiological diagnosis of the SLAP lesions and compares accuracy of arthroscopic and MRI classifications. METHODS: One hundred thirty-two patients with positive physical examination signs using O'Brien, Yergason, resistance supination external rotation and Krank tests and MRI findings are included in the study. Shoulder MRIs were obtained for all patients within three months prior to the surgeries. SLAP lesion is detected in 90 and 102 patients according to MRI and arthroscopy, respectively. Arthroscopic and MRI classifications of the patients were performed according to modified Snyder classification. RESULTS: Sensitivity and specificity of the MRI were found as 70.59 and 40%, respectively. No difference was detected between MRI and arthroscopy classifications in 52 (39%) patients. Although the diagnosis was compatible with arthroscopy in 34 (25%) patients, the classification was incompatible. In 46 (34%) of patients the diagnosis was incompatible with the MRI. CONCLUSION: Although MRI is a good diagnostic tool for SLAP lesions, its use for the classification is limited. Level of evidence Level III, Diagnostic study.

Hyperperfusion in carotid stenting patients.

PURPOSE: This study aimed to define hyperperfusion in carotid stenting patients without excluding patients with stenosis on the contralateral side. MATERIALS AND METHODS: A total of 32 patients were enrolled. Prestent computed tomography perfusions were performed within 1 week before stenting, poststent perfusions 3 days after stenting. Prestent relative cerebral blood volume, relative cerebral blood flow, and relative mean transient time (rMTT) were calculated by dividing measurements from ipsilateral stent sides to contralateral sides and prestent difference mean transit time (dMTT) by subtracting contralateral mean transient time (MTT) from ipsilateral MTT. Poststent values were calculated similarly. For differences between prestent and poststent values, independent t test was used between groups and paired sample t test within the groups. RESULTS: Of the 31 patients, 4 showed poststent clinical hyperperfusion syndrome. Six showed poststent radiologic hyperperfusion with increased cerebral blood flow, increased or spared cerebral blood volume, and shortened MTT values, but only 1 demonstrated clinical hyperperfusion. Between normal and hyperperfused groups, only appreciable difference was noted in prestent and poststent dMTT without statistical significance. Within the groups, only statistical difference (P < 0.001) was noted in rMTT and dMTT in normal groups and no significant difference in the hyperperfused group. CONCLUSIONS: Radiologic hyperperfusion does not match clinical hyperperfusion. Normal group responded to stenting with statistically significant changes of rMTT and dMTT. Hyperperfusion mostly occurred in the contralateral critically stenosed patients. The hyperperfused group, due to similar MTT of both hemispheres and ipsilateral internal carotid artery being the main feeder of both hemispheres, did not show significant changes in their rMTT and dMTT values after stenting. This shows that reduced hemodynamic reserve is the main reason behind the hyperperfusion after carotid stenting.

The effect of obesity on brain diffusion alteration in patients with obstructive sleep apnea.

PURPOSE: We investigated diffusion alterations in specific regions of the brain in morbid obese, obese, and nonobese OSA patients and searched whether there is a correlation between BMI and ADC values. MATERIALS AND METHODS: DWIs of 65 patients with OSA were evaluated. The patients were classified according to BMI as morbid obese (n = 16), obese (n = 27), and nonobese (control, n = 22) groups. ADC measurements were performed from 24 different regions of the brain in each patient. The relationship of BMI with ADC values was searched. RESULTS: The ADC values in hypothalamus, insular cortex, parietal cortex, caudate nucleus, frontal white matter, and posterior limb of internal capsule were all increased in obese patients (n = 43) compared to control group. The ADC values of midbrain, hypothalamus, orbitofrontal cortex, and parietal cortex were significantly increased in morbid obese compared to obese patients. In obese patients, the degree of BMI was positively correlated with ADC values of orbitofrontal cortex, parietal cortex, and hypothalamus. CONCLUSION: We observed increasing brain vasogenic edema with increasing BMI, suggesting that the main reason of brain diffusion alteration in patients with OSA could be obesity related.

MRI findings in crural compartment syndrome: a case series.

Compartment syndrome occurs when the pressure inside a closed fascial compartment increases to a level that compromises the blood supply to the structures. Untreated compartment syndrome commonly leads to muscle necrosis, limb amputation, and, if it is severe, which is seen in large compartments, renal failure and death may occur. We discussed MRI findings of crural compartment syndrome based on the case series.

Differential Diagnosis of Diabetic Foot Osteomyelitis and Charcot Neuropathic Osteoarthropathy with Deep Learning Methods.

Our study aims to evaluate the potential of a deep learning (DL) algorithm for differentiating the signal intensity of bone marrow between osteomyelitis (OM), Charcot neuropathic osteoarthropathy (CNO), and trauma (TR). The local ethics committee approved this retrospective study. From 148 patients, segmentation resulted in 679 labeled regions for T1-weighted images (comprising 151 CNO, 257 OM, and 271 TR) and 714 labeled regions for T2-weighted images (consisting of 160 CNO, 272 OM, and 282 TR). We employed both multi-class classification (MCC) and binary-class classification (BCC) approaches to compare the classification outcomes of CNO, TR, and OM. The ResNet-50 and the EfficientNet-b0 accuracy values were computed at 96.2% and 97.1%, respectively, for T1-weighted images. Additionally, accuracy values for ResNet-50 and the EfficientNet-b0 were determined at 95.6% and 96.8%, respectively, for T2-weighted images. Also, according to BCC for CNO, OM, and TR, the sensitivity of ResNet-50 is 91.1%, 92.4%, and 96.6% and the sensitivity of EfficientNet-b0 is 93.2%, 97.6%, and 98.1% for T1, respectively. For CNO, OM, and TR, the sensitivity of ResNet-50 is 94.9%, 83.6%, and 97.9% and the sensitivity of EfficientNet-b0 is 95.6%, 85.2%, and 98.6% for T2, respectively. The specificity values of ResNet-50 for CNO, OM, and TR in T1-weighted images are 98.1%, 97.9%, and 94.7% and 98.6%, 97.5%, and 96.7% in T2-weighted images respectively. Similarly, for EfficientNet-b0, the specificity values are 98.9%, 98.7%, and 98.4% and 99.1%, 98.5%, and 98.7% for T1-weighted and T2-weighted images respectively. In the diabetic foot, deep learning methods serve as a non-invasive tool to differentiate CNO, OM, and TR with high accuracy.

Brain diffusion changes in obstructive sleep apnoea syndrome.

BACKGROUND: Obstructive sleep apnoea syndrome (OSAS) is a disorder characterized by repeated apnoeic episodes during sleep. Neurocognitive changes secondary to OSAS are likely to occur due to hypoxia in certain brain locations. Advances in magnetic resonance imaging technology, such as diffusion-weighted imaging (DWI), enable non-invasive and accurate identification of OSAS-induced changes. OBJECTIVE: We aimed to use DWI to investigate changes in the brain secondary to hypoxia in OSAS. METHODS: Eighty-eight patients underwent polysomnography and were classified as non-OSAS, mild-moderate OSAS and severe OSAS sufferers. DWI was used to evaluate 14 areas of the brain, and apparent diffusion coefficients (ADCs) were calculated. We investigated whether there were differences in the ADC values in specific areas of the brain between the non-OSAS and OSAS patients. RESULTS: We measured the ADC values of the 68 newly diagnosed OSAS patients (21 mild, 15 moderate and 32 severe) and of 20 healthy controls. There were significant increases in the ADC values in the hippocampus, amygdala and putamen in OSAS patients. Compared to the non-OSAS subjects, the ADC values of the putamen in severe OSAS patients, those of the hippocampus in moderate or severe OSAS patients and those of the amygdala in moderate OSAS patients were significantly increased. A negative correlation between the lowest oxygen saturation during sleep and the ADC values of the hippocampus and amygdala was found. CONCLUSIONS: Increased ADC levels in the hippocampus, amygdala and putamen in OSAS patients indicate hypoxia and likely cause vasogenic oedema in specific regions of the brain.

Radiomics method in the differential diagnosis of diabetic foot osteomyelitis and charcot neuroarthropathy.

OBJECTIVES: Our study used a radiomics method to differentiate bone marrow signal abnormality (BMSA) between Charcot neuroarthropathy (CN) and osteomyelitis (OM). METHODS AND MATERIALS: The records of 166 patients with diabetic foot suspected CN or OM between January 2020 and March 2022 were retrospectively examined. A total of 41 patients with BMSA on MRI were included in this study. The diagnosis of OM was confirmed histologically in 24 of 41 patients. We clinically followed 17 patients as CN with laboratory tests. We also included 29 nondiabetic patients with traumatic (TR) BMSA on MRI as the third group. Contours of all BMSA on T 2 - and T1 -weighted images in three patient groups were segmented semi-automatically on ManSeg (v.2.7d). The T1 and T2 features of three groups in radiomics were statistically evaluated. We applied the multi-class classification (MCC) and binary-class classification (BCC) methodologies to compare results. RESULTS: For MCC, the accuracy of Multi-Layer Perceptron (MLP) was 76.92% and 84.38% for T1 and T2, respectively. According to BCC, for CN, OM, and TR BMSA, the sensitivity of MLP is 74%, 89.23%, and 76.19% for T1, and 90.57%, 85.92%, 86.81% for T2, respectively. For CN, OM, and TR BMSA, the specificity of MLP is 89.16%, 87.57%, and 90.72% for T1 and 93.55%, 89.94%, and 90.48% for T2 images, respectively. CONCLUSION: In diabetic foot, the radiomics method can differentiate the BMSA of CN and OM with high accuracy. ADVANCES IN KNOWLEDGE: The radiomics method can differentiate the BMSA of CN and OM with high accuracy.

Comparing Perfusion Data of CE-MRI, SWI, and CTA with MR Perfusion in Stroke.

BACKGROUND: To evaluate the perfusion status of patients with acute stroke, different imaging tools are used depending on the condition. CT-CT Angiography and MRI are indispensable imaging tools to diagnose and manage stroke patients. Susceptibility-weighted imaging (SWI) also has been used lately to evaluate vascular structures and consequences of stroke in the brain. We aimed to compare CE-MRI, SWI, and CTA with DSC-MRP in terms of perfusion. METHODS: Stroke cases of CE-MRI, SWI, CTA and DSC-MRP of 44 patients were included. Collateralization was assessed on CTA; leptomeningeal-pial collateralization (LPC) and parenchymal enhancement (PE) on CE-MRI; prominent vessel sign (PVS) and hemorrhagic transformation on SWI. Results were compared with MRP maps and the ratio of penumbra/infarct core. RESULTS: LPC was correlated with increased CBV (p<0,001), decreased CBF (p=0,026), and prolonged MTT and TTP (p=0,001 and p=0,003). LPC was observed more often in cases with infarct zones with penumbra compared to those without penumbra (p=0,024). PE was positively correlated with prolonged MTT and TTP (p=0,015 and p=0,031). Moreover, there was a positive relationship between PE and increased penumbra ratio over the infarct core (p=0,037). Ipsilateral PVS was associated with increased CBV (p=0,004) and decreased CBF (p=0,002). No relationship was found between collateralization grading on CTA and perfusion metrics or penumbra ratio. CONCLUSION: In conclusion; ipsilateral PVS can be a measure of CBV and CBF. LPC on CE-MRI can be a sign of an increase in CBV. PE can show larger penumbra. CE-MRI with SWI can be used to evaluate perfusion status.

MRI findings in thoracic outlet syndrome.

We discuss MRI findings in patients with thoracic outlet syndrome (TOS). A total of 100 neurovascular bundles were evaluated in the interscalene triangle (IS), costoclavicular (CC), and retropectoralis minor (RPM) spaces. To exclude neurogenic abnormality, MRIs of the cervical spine and brachial plexus (BPL) were obtained in neutral. To exclude compression on neurovascular bundles, sagittal T1W images were obtained vertical to the longitudinal axis of BPL from spinal cord to the medial part of the humerus, in abduction and neutral. To exclude vascular TOS, MR angiography (MRA) and venography (MRV) of the subclavian artery (SA) and vein (SV) in abduction were obtained. If there is compression on the vessels, MRA and MRV of the subclavian vessels were repeated in neutral. Seventy-one neurovascular bundles were found to be abnormal: 16 arterial-venous-neurogenic, 20 neurogenic, 1 arterial, 15 venous, 8 arterial-venous, 3 arterial-neurogenic, and 8 venous-neurogenic TOS. Overall, neurogenic TOS was noted in 69%, venous TOS in 66%, and arterial TOS in 39%. The neurovascular bundle was most commonly compressed in the CC, mostly secondary to position, and very rarely compressed in the RPM. The cause of TOS was congenital bone variations in 36%, congenital fibromuscular anomalies in 11%, and position in 53%. In 5%, there was unilateral brachial plexitis in addition to compression of the neurovascular bundle. Severe cervical spondylosis was noted in 14%, contributing to TOS symptoms. For evaluation of patients with TOS, visualization of the brachial plexus and cervical spine and dynamic evaluation of neurovascular bundles in the cervicothoracobrachial region are mandatory.

Follow-Up of High-Grade Glial Tumor; Differentiation of Posttreatment Enhancement and Tumoral Enhancement by DCE-MR Perfusion.

PURPOSE: To search for the utility of DCE-MRP to differentiate between posttreatment enhancement (PT) and tumoral enhancement (TM) in high-grade glial tumors. MATERIALS AND METHODS: Thirty-four patients with glioma (11 grade 3; 23 grade 4) were enrolled. Enhancement in the vicinity of the resection cavity demonstrated by DCE-MRP was taken into consideration. Based on the follow-up scans, reoperation or biopsy results, the enhancement type was categorized as PT or TM. Measurements were performed at the enhancing area near the resection cavity (ERC), nearby (NNA) and contralateral nonenhancing areas (CLNA). Perfusion parameters of the ERC were also subtracted from NNA and CLNA. Intragroup comparison (paired sample t-test) and intergroup comparison (Student's t-test) were made. RESULTS: There were 7 PTs and 27 TMs. In the PT, the subtracted values of Ve and IAUC from the CLNA and NNA and the subtracted value of Kep from NNA were statistically different. In TM, all metrics were significantly different comparing the CLNA and NNA. Comparing PT with TM, Ktrans, IAUC, Kep, and subtracted values of Ktrans and IAUC from both NNA and CLNA were significantly different. CONCLUSIONS: In PT, only Ktrans values did not reveal any difference comparing NNA and CLNA. To differentiate PT from TM, Ktrans, Kep, IAUC, and subtracted values of Ktrans and IAUC from NNA and CLNA can be used. These findings are in concordance with literature.

Dynamic Contrast-Enhanced MR Perfusion in Differentiation of Benign and Malignant Brain Lesions.

BACKGROUND: We aimed to differentiate Glioblastoma Multiforme (GBM) from benign lesions like Developmental Venous Anomaly (DVA) and Cavernous Malformation (CM) by Dynamic Contrast-Enhanced MR Perfusion (DCE-MRP) markers such as Ktrans, Ve, Kep, and IAUC. METHODS: We retrospectively evaluated 20 patients; 10 GBM as the malignant group, 5 CM and 5 DVA as the benign group. Ktrans, Kep, Ve, and IAUC parameters were measured by DCE-MRP, within the lesion, at perilesional nonenhancing white matter (PLWM) and contralateral normal appearing white matter (CLWM). RESULTS: All benign and malignant lesions exhibited significantly increased Ktrans, Ve, and IAUC values compared to PLWM and CLWM (p < 0.001, p=0.006 and p<0.001). Subtracted Kep values between lesion and PLWM were significantly different between the benign and malignant groups, as the malignant group exhibited higher subtracted Kep values (p 0.035). For the malignant group; Ktrans and IAUC values at the lesion were positively correlated (r 0.911), while Kep and Ve at CLWM were negatively and strongly correlated (r 0.798). For the benign group; Ktrans with Ve and Ktrans with IAUC at lesion (r 0.708 and r 0.816 respectively), Ktrans and IAUC at PLWM (r 0.809), Ktrans and IAUC at CLWM(r 0.798) were strongly and positively correlated. Ktrans, Ve, and IAUC values can be used to restrict the lesion in both groups. CONCLUSION: Ktrans strongly correlates with IAUC and they can be used instead of each other in both benign and malignant lesions. Classical DCE-MRP parameters cannot be used in the differentiation of malignant lesions from benign vascular lesions. However, subtracted Kep values can be used to differentiate GBM from benign vascular lesions.