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.

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.

Early stage T1-weighted perfusion magnetic resonance imaging: a factor that predicts local control response in patients with meningioma who underwent gamma-knife radiosurgery.

BACKGROUND: Gamma-knife radiosurgery (GKRS) is an alternative treatment option for selected intracranial meningiomas. The study's aim is to demonstrate the advantages of T1-weighted perfusion magnetic resonance imaging (T1-PMRI) by measuring the volume transfer coefficient (Ktrans) values in the prediction of local response for patients with meningioma who have undergone GKRS consecutively. METHODS: The data of patients diagnosed radiologically with WHO grade 1 intracranial meningiomas was collected prospectively. The patients who were treated consecutively with GKRS at our institution (September 2017-September 2018) were included. After GKRS, the patients were followed up at the defined periods with routine contrast-enhanced MRI and T1-PMRI by measuring the Ktrans. The comparison between the pre-treatment and third-month post-treatment (PO3M) Ktrans was done using the Wilcoxon signed-rank test. RESULTS: Thirty-one patients with 36 tumors have undergone GKRS. Twenty-two patients were female. The mean age was 55.3 years. The mean pre-GKRS volume was 7.67 ccs. The mean 50% radiation isodose was 12.2 Gy. The local tumor control rate was 100%. Fourteen tumors were regressed fully at the last MRI. PO3M Ktrans decreased when compared with the pre-GKRS values (p < 0.0001). However, the numerical decrease in tumor volumes on contrast-enhanced MRI was not statistically significant (p = 0.117). CONCLUSION: Changes between Ktrans on PO3M and pre-GKRS T1-PMRI were more useful in determining the early response to GKRS in patients with meningioma than volumetric changes. Therefore, Ktrans should be taken as a reference to predict the early response to GKRS in follow-up imaging scans.

Evaluation of CT and MRI Imaging Results of Radicular Cysts, Odontogenic Keratocysts, and Dentigerous Cysts and their Contribution to the Differential Diagnosis.

AIM: This study aimed to evaluate the contribution of the MRI and CT results to the differential diagnosis of histopathologically different odontogenic cysts. BACKGROUND: Odontogenic cysts are commonly seen in the jaw bone and their surgical operations have an important place in the practice of maxillofacial surgery; treatment options for these cysts differ according to their histopathology. Differential results that can be obtained from the radiological evaluations of different cyst groups will allow the surgeon to plan a more accurate approach at the beginning of the operation. In this study, computed tomography (CT) and magnetic resonance imaging (MRI) results of different cyst groups were interpreted together with their histopathological diagnosis. METHODS: CT and MRI results of 17 patients aged between 19-61 were evaluated, whose histopathological diagnosis consisted of 3 radicular cysts (RC), a total of 9 odontogenic keratocysts (OKC) of which 4 were inflamed, and a total of 5 dentigerous cysts (DC) of which one of them was inflammatory. RESULTS: In the CT scan, all cysts showed lytic, a sclerotic surrounding, and showed MRI peripheral enhancement, whereas solid nodular enhancement was only observed in OKCs. Edema and/or air in the surrounding bone medulla was observed in the infected lesions. OKC was heterogeneous, whereas RC and DC were more homogeneous. Diffusion restriction was observed to be frequent in OKCs. The OKCs were ellipsoidal in appearance and were located parallel to the long axis of the bone, and their dimensions were observed to be larger than the other cysts. OKCs may be accompanied by unerupted teeth. Radicular cysts were located perpendicular to the long axis of the bone and were globular in appearance, and their dimensions were smaller and more homogeneous compared to the OKCs. Dentigerous cysts are also accompanied by an unerupted tooth, and their peripheral enhancement is minimal and homogeneous. However, dentigerous cysts can be dense in content and smaller in size, and ellipsoidal localization is more common than OKCs. CONCLUSION: In addition to classic panoramic radiography in the evaluation and differential diagnosis of maxillary and mandibular lesions, CT and MRI evaluations can provide helpful information to the surgeon and pathologist in making the diagnosis and may further help plan the operation.

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.

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.

Three dimensional patient-specific guides for guide pin positioning in reverse shoulder arthroplasty: An experimental study on different glenoid types.

INTRODUCTION: Incorrect positioning is one of the main factors for glenoid component loosening in reverse shoulder arthroplasty and component placement can be challenging. This study aimed to assess whether Patient-Specific Instrumentation (PSI) provides better guide pin positioning accuracy and is superior to standard guided and freehand instrumentation methods in cases of glenoid bone deformity. MATERIALS AND METHODS: Based on the Walch classification, five different scapula types were acquired by computed tomography (CT). For each type, two different surgeons placed a guide pin into the scapula using three different methods: freehand method, conventional non-patient-specific guide, and PSI guide. Each method was repeated five times by both surgeons. In these experiments, a total of 150 samples of scapula models were used (5 × 2 × 3 × 5 = 150). Post-operative CT scans of the samples with the guide pin were digitally assessed and the accuracy of the pin placement was determined by comparison to the preoperative planning on a three-dimensional (3D) model. RESULTS: The PSI method showed accuracies to the preoperative plan of 2.68 (SD 2.10) degrees for version angle (p < .05), 2.59 (SD 2.68) degrees for inclination angle (p < .05), and 1.55 (SD 1.26) mm for entry point offset (p < .05). The mean and standard deviation errors compared to planned values of version angle, inclination angle, and entry point offset were statistically significant for the PSI method for the type C defected glenoid and non-arthritic glenoid. CONCLUSION: Using the PSI guide created by an image processing software tool for guide pin positioning showed advantages in glenoid component positioning over other methods, for defected and intact glenoid types, but correlation with clinical outcomes should be examined.

A Treatment-Response Comparison Study of Resting-State Functional Magnetic Resonance Imaging Between Standard Treatment of SSRI and Standard Treatment of SSRI Plus Non-dominant Hand-Writing Task in Patients With Major Depressive Disorder.

Background: Researches have recently shifted from functional/structural imaging studies to functional connectivity (FC) studies in major depressive disorder (MDD). We aimed to compare treatment response of two treatment groups before and after treatment, in terms of both with psychiatric evaluation scales and resting-state functional connectivity (RSFC) changes in order to objectively demonstrate the possible contribution of the non-dominant hand-writing exercise (NHE) effect on depression treatment. Methods: A total of 26 patients who were right-handed women with similar sociodemographic characteristics were enrolled. Their pre-treatment resting-state functional magnetic resonance imaging (rs-fMRI) and neuropsychiatric tests were recorded, and then, patients were divided into two groups randomly. A standard treatment (ST) (fix sertraline 50 mg/day) was given to both groups. One randomly selected group was given the NHE in addition to the ST. After 8 weeks of treatment, all patients were reevaluated with rs-fMRI and neuropsychiatric tests. Pre- and post-treatment FC changes within the groups and post-treatment connectivity changes between groups were evaluated. Results: Post-treatment neuropsychiatric tests were significantly different in both groups. Post-treatment, two brain regions' connectivity changed in the ST group, whereas 10 brain regions' connectivity changed significantly in the ST + NHE group. When treatment groups were compared with each other after the treatment, the FC of 13 regions changed in the ST + NHE group compared to the ST group (p-unc/p-PFD <0.05). The density of connectivity changes in the frontal and limbic regions, especially connectivities shown to change in depression treatment, in the ST + NHE group indicates a positive contribution to depression treatment, which is also supported by neuropsychiatric scale changes. Conclusion: NHE, which we developed with inspiration from the Eye Movement Desensitization and Reprocessing (EMDR) method, showed significantly more connecitivity changes related with MDD treatment. Beyond offering a new additional treatment method, our study will also contribute to the current literature with our efforts to evaluate all brain regions and networks that may be related to MDD and its treatment together, without being limited to a few regions. Trial Registration: The rs-fMRI and treatment registers were recorded in the BizMed system, which is the patient registration system of Bezmialem Vakif University Medicine Faculty, under the BAP support project approval code and the registration number 3.2018/8.

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.

Differentiation of relapsing-remitting and secondary progressive multiple sclerosis: a magnetic resonance spectroscopy study based on machine learning.

INTRODUCTION: Magnetic resonance imaging (MRI) is the most important tool for diagnosis and follow-up in multiple sclerosis (MS). The discrimination of relapsing-remitting MS (RRMS) from secondary progressive MS (SPMS) is clinically difficult, and developing the proposal presented in this study would contribute to the process. OBJECTIVE: This study aimed to ensure the automatic classification of healthy controls, RRMS, and SPMS by using MR spectroscopy and machine learning methods. METHODS: MR spectroscopy (MRS) was performed on a total of 91 participants, distributed into healthy controls (n=30), RRMS (n=36), and SPMS (n=25). Firstly, MRS metabolites were identified using signal processing techniques. Secondly, feature extraction was performed based on MRS Spectra. N-acetylaspartate (NAA) was the most significant metabolite in differentiating MS types. Lastly, binary classifications (healthy controls-RRMS and RRMS-SPMS) were carried out according to features obtained by the Support Vector Machine algorithm. RESULTS: RRMS cases were differentiated from healthy controls with 85% accuracy, 90.91% sensitivity, and 77.78% specificity. RRMS and SPMS were classified with 83.33% accuracy, 81.81% sensitivity, and 85.71% specificity. CONCLUSIONS: A combined analysis of MRS and computer-aided diagnosis may be useful as a complementary imaging technique to determine MS types.

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.

Comparison of Subtracted Computed Tomography from Computed Tomography Perfusion and Digital Subtraction Angiography in Residue Evaluation of Treated Intracranial Aneurysms.

BACKGROUND: Assessing clipped intracranial aneurysms for residues or incomplete occlusions is critical. Digital subtraction angiography (DSA) has been the gold standard for this. Previously, we presented subtracted computed tomography angiography (sub-CTA) from computed tomography perfusion as a more effective noninvasive technique for clipped aneurysms. The aim of this study was to compare effectiveness of sub-CTA with DSA in residue evaluation. METHODS: A retrospective study of 17 patients with aneurysmal subarachnoid hemorrhage operated on at our institution between November 1, 2016, and December 31, 2018, was performed. Residue aneurysms were evaluated with both sub-CTA and DSA. Positive predictive value and negative predictive value were calculated. Correlation between techniques was determined by the McNemar test and κ value. RESULTS: Sensitivity of sub-CTA in residue evaluation was low in aneurysms ≤3 mm (positive predictive value = 60%). DSA detected residue aneurysm in 29% (5/17) of patients, whereas sub-CTA detected residue aneurysm in 11% (2/17). Only 40% of aneurysms (2/5) were demonstrated by sub-CTA, all >3 mm; 60% (3/5) were missed, all ≤3 mm. CONCLUSIONS: This is the first study comparing the effectiveness of sub-CTA from computed tomography perfusion with DSA in residue aneurysm evaluation. Our results were suggestive, but not conclusive. DSA is still the gold standard in residue evaluation. Sub-CTA from computed tomography perfusion can be a reliable method in evaluation of residual aneurysm >3 mm.

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.

Magnetic Resonance Spectroscopy Features of the Visual Pathways in Patients with Glaucoma.

PURPOSE: The aim of the study was to investigate any metabolic changes on magnetic resonance spectroscopy (MRS) throughout the visual pathway of the brain in patients with glaucoma and a control group and correlate the results with clinical findings. MATERIAL AND METHODS: A total of 87 patients were enrolled in the study, 30 healthy controls, 25 glaucoma, 16 suspected glaucoma (GS) and 16 ocular hypertension (OHT) patients. A single voxel MRS on TE 30 ms was performed by placing the volume of interest (VOI) on the corpus geniculatum laterale (CGL) and primary visual cortex (VC). Peak values of metabolites, such as N­acetyl aspartate (NAA), creatine (Cr), choline (Cho) and Myo-inositol (Ins) were investigated on MRS. The MRS results were correlated with age, intraocular pressure (IOP), retinal nerve fiber length (RNFL), mean deviation (MD) and cup disk ratio (CD). RESULTS: The NAA values obtained from the CGL in glaucoma and GS cases were lower than the healthy control group. The Cho values at CGL in glaucoma were lower than GS and controls. There was a negative correlation between NAA values of the VC and CD in glaucoma cases. Additionally, there was a negative correlation between age and RNFL in both glaucoma and GS cases. CONCLUSION: The use of MRS can reveal neurodegeneration in CGL and VC in patients with glaucoma. Depiction of metabolic changes throughout the visual pathways via MRS will guide the treatment planning and follow-up in glaucoma and GS cases.

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.

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.

Craniocervical Dissections: Radiologic Findings, Pitfalls, Mimicking Diseases: A Pictorial Review.

BACKGROUND: Craniocervical Dissections (CCD) are a crucial emergency state causing 20% of strokes in patients under the age of 45. Although DSA (digital substraction angiography) is regarded as the gold standard, noninvasive methods of CT, CTA and MRI, MRA are widely used for diagnosis. AIM: Our aim is to illustrate noninvasive imaging findings in CCD. CONCLUSION: Emphasizing on diagnostic pitfalls, limitations and mimicking diseases.

Pontine bleeding following drainage of subdural hematoma in craniospinal hypotension.

Craniospinal hypotension is the syndrome of orthostatic headache associated with low cerebrospinal fluid pressure. Imaging findings are usually explained by Monro-Kellie hypothesis stating that the craniospinal compartment is incompressible and any increase in volume of one of the craniospinal constituents (blood, cerebrospinal fluid, and parenchyma) must be compensated by a decrease in volume of another constituent or vice versa. We report a case of craniospinal hypotension in whom drainage of subdural hematoma upon clinical impairments resulted in pontine hemorrhage, supporting Monro-Kellie hypothesis.