Conventional Magnetic Resonance Imaging Findings Research Articles

Usefulness of Olfactory Bulb Measurement in 3D-FIESTA in Differentiating Parkinson Disease from Atypical Parkinsonism.

Parkinson disease is a prevalent disease, with olfactory dysfunction recognized as an early nonmotor manifestation. It is sometimes difficult to differentiate Parkinson disease from atypical parkinsonism using conventional MR imaging and motor symptoms. It is also known that olfactory loss occurs to a lesser extent or is absent in atypical parkinsonism. To the best of our knowledge, no study has examined olfactory bulb changes to differentiate Parkinson disease from atypical parkinsonism, even in an early diagnosis, and its association with conventional MR imaging findings. Hence, we aimed to assess the utility of olfactory bulb measurements in differentiating Parkinson disease from atypical parkinsonism even in the early stage. In this retrospective study, we enrolled 108 patients with Parkinson disease, 13 with corticobasal syndrome, 15 with multiple system atrophy, and 17 with progressive supranuclear palsy who developed parkinsonism. Thirty-nine age-matched healthy subjects served as controls. All subjects underwent conventional MR imaging and 3D FIESTA for olfactory bulb measurements using manual ROI quantification of the cross-sectional olfactory bulb area using the coronal plane. Bilateral olfactory bulb measurements were averaged. For group comparisons, we used the Welch t test, and we assessed diagnostic accuracy using receiver operating characteristic analysis. Patients with Parkinson disease had a mean olfactory bulb area of 4.2 (SD, 1.0 mm2), significantly smaller than in age-matched healthy subjects (6.6 [SD, 1.7 mm2], P < .001), and those with corticobasal syndrome (5.4 [SD, 1.2 mm2], P < .001), multiple system atrophy (6.5 [SD, 1.2 mm2], P < .001), and progressive supranuclear palsy (5.4 [SD, 1.2 mm2], P < .001). The receiver operating characteristic analysis for the olfactory bulb area measurements showed good diagnostic performance in differentiating Parkinson disease from atypical parkinsonism, with an area under the curve of 0.87, an optimal cutoff value of 5.1 mm2, and a false-positive rate of 18%. When we compared within 2 years of symptom onset, the olfactory bulb in Parkinson disease (4.2 [SD, 1.1 mm2]) remained significantly smaller than in atypical parkinsonism (versus corticobasal syndrome (6.1 [SD, 0.7 mm2]), P < .001; multiple system atrophy (6.3 [SD, 1.4 mm2]), P < .001; and progressive supranuclear palsy (5.2 [1.3 mm2], P = .003, respectively). 3D FIESTA-based olfactory bulb measurement holds promise for distinguishing Parkinson disease from atypical parkinsonism, especially in the early stage.

Conventional magnetic resonance imaging key features for distinguishing pathologically confirmed corticobasal degeneration from its mimics: a retrospective analysis of the J-VAC study.

Due to the indistinguishable clinical features of corticobasal syndrome (CBS), the antemortem differentiation between corticobasal degeneration (CBD) and its mimics remains challenging. However, the utility of conventional magnetic resonance imaging (MRI) for the diagnosis of CBD has not been sufficiently evaluated. This study aimed to investigate the diagnostic performance of conventional MRI findings in differentiating pathologically confirmed CBD from its mimics. Semiquantitative visual rating scales were employed to assess the degree and distribution of atrophy and asymmetry on conventional T1-weighted and T2-weighted images. Additionally, subcortical white matter hyperintensity (SWMH) on fluid-attenuated inversion recovery images were visually evaluated. In addition to 19 patients with CBD, 16 with CBD mimics (progressive supranuclear palsy (PSP): 9, Alzheimer's disease (AD): 4, dementia with Lewy bodies (DLB): 1, frontotemporal lobar degeneration with TAR DNA-binding protein of 43kDa(FTLD-TDP): 1, and globular glial tauopathy (GGT): 1) were investigated. Compared with the CBD group, the PSP-CBS subgroup showed severe midbrain atrophy without SWMH. The non-PSP-CBS subgroup, comprising patients with AD, DLB, FTLD-TDP, and GGT, showed severe temporal atrophy with widespread asymmetry, especially in the temporal lobes. In addition to over half of the patients with CBD, two with FTLD-TDP and GGT showed SWMH, respectively. This study elucidates the distinct structural changes between the CBD and its mimics based on visual rating scales. The evaluation of atrophic distribution and SWMH may serve as imaging biomarkers of conventional MRI for detecting background pathologies.

MRI-based Texture Analysis in Differentiation of Benign and Malignant Vertebral Compression Fractures.

The diagnosis and characterization of vertebral compression fractures are very important for clinical management. In this evaluation, which is usually performed with diagnostic (conventional) imaging, the findings are not always typical or diagnostic. Therefore, it is important to have new information to support imaging findings. Texture analysis is a method that can evaluate information contained in diagnostic images and is not visually noticeable. This study aimed to evaluate the magnetic resonance images of cases diagnosed with vertebral compression fractures by the texture analysis method, compare them with histopathological data, and investigate the effectiveness of this method in the differentiation of benign and malignant vertebral compression fractures. Fifty-five patients with a total of 56 vertebral compression fractures were included in the study. Magnetic resonance images were examined and segmented using Local Image Feature Extraction (LIFEx) software, which is an open-source program for texture analysis. The results were compared with the histopathological diagnosis. The application of the Decision Tree algorithm to the dataset yielded impressively accurate predictions (≈95% in accuracy, precision, and recall). Interpreting tissue analysis parameters together with conventional magnetic resonance imaging findings can improve the abilities of radiologists, lead to accurate diagnoses, and prevent unnecessary invasive procedures. Further prospective trials in larger populations are needed to verify the role and performance of texture analysis in patients with vertebral compression fractures.

Evaluation of Uterine Carcinosarcoma and Uterine Endometrial Carcinoma Using Magnetic Resonance Imaging Findings and Texture Features.

Aim This study aimed to evaluate the diagnostic feasibility of magnetic resonance imaging (MRI) findings and texture features (TFs) for differentiating uterine endometrial carcinoma from uterine carcinosarcoma. Methods This retrospective study included 102 patients who were histopathologically diagnosed after surgery with uterine endometrial carcinoma (n=68) or uterine carcinosarcoma (n=34) between January 2008 and December 2021. We assessed conventional MRI findings and measurements (cMRFMs) and TFs on T2-weighted images (T2WI) and apparent diffusion coefficient (ADC) map, as well as their combinations, in differentiating between uterine endometrial carcinoma and uterine carcinosarcoma. The least absolute shrinkage and selection operator (LASSO) was used to select three features with the highest absolute value of the LASSO regression coefficient for each model and construct a discriminative model. Binary logistic regression analysis was used to analyze the disease models and conduct receiver operating characteristic analyses on the cMRFMs, T2WI-TFs, ADC-TFs, and their combined model to compare the two diseases. Results A total of four models were constructed from each of the three selected features. The area under the curve (AUC) of the discriminative model using these features was 0.772, 0.878, 0.748, and 0.915 for the cMRFMs, T2WI-TFs, ADC-TFs, and a combined model of cMRFMs and TFs, respectively. The combined model showed a higher AUC than the other models, with a high diagnostic performance (AUC=0.915). Conclusion A combined model using cMRFMs and TFs might be helpful for the differential diagnosis of uterine endometrial carcinoma and uterine carcinosarcoma.

Occipital emissary vein existence and its impact on the diagnosis of idiopathic intracranial hypertension in pediatric patients.

This study aimed to investigate the efficacy of occipital emissary vein (OEV) detection in the diagnosis of idiopathic intracranial hypertension (IHH) in the pediatric age group, and to compare the prevalence and luminal diameter of OEV in patients with IHH and in healthy control subjects. Conventional magnetic resonance imaging findings were assessed in the patients with IHH and in healthy control subjects who were under the age of 18, by two observers. The presence and luminal dimension of OEV and transverse sinus stenosis were also evaluated and compared between these two groups with magnetic resonance venography techniques. The rate of OEV existence was 7 times higher in the IIH group compared to the control group based on the second observer outcome (p = 0.010, OR = 7.0), with a very good interobserver agreement (Ƙ = 0.85). The dimension of OEV ranged between 0.6 and 2.5mm. There was no correlation found between the opening pressure and the dimension of OEV (p = 0.834). In conclusion, OEV existence could be an additional radiological finding for diagnosing IHH among pediatric patients, alongside other conventional findings.

The correlation of conventional and advanced MRI findings with cognitive function in multiple sclerosis: A systematic review and meta-analysis

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&lt;0.0001). The SDMT test positively correlated with fractional anisotropy (FA) with a correlation coefficient of 0.351 (P&lt;0.0001) and inversely correlated with T2 lesion volume with a correlation coefficient of -0.367 (P&lt;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.

Cystic Renal Masses: characterization with Diffusion- Weighted Imaging versus ContrastEnhanced Magnetic Resonance Imaging

Purpose To compare the diagnostic performance of magnetic resonance imaging (MRI), and MRI with diffusion-weighted imaging (DWI) in the characterization of cystic renal lesions. Materials and Methods Thirty-six adult patients underwent MRI (at 1.5 T), and DWI (at b-values of 0, 400 and 800 s/mm2) for characterization of 63 cystic renal lesions. There were 16 malignant renal cystic lesions (9 cystic clear cell RCC, 4 cystic papillary RCC, 3 massively necrotic RCC) opposite to 37 benign renal cystic lesions, 6 renal abscesses and 4 renal hemorrhagic cysts. A composite reference standards including histology, typical imaging criteria, and follow-up imaging was employed. To determine the diagnostic performance of imaging modalities, area-under-curve (AUC) was calculated by receiver-operating-characteristic analysis and compared. Fisher's exact test was used to compare the diagnostic accuracies and confidence levels with MRI, and MRI + DWI. Furthermore, DWI-ADC cutoff point to detect malignant cystic renal lesions, had been estimated and its diagnostic performance had been tested in term of sensitivity and specificity, PPD and NPV as compared to that of CE-MRI Results AUC for CE-MRI (0.915) and DW-MRI (0.834) in the differentiation between benign and malignant lesions (among all study cases) were within corresponding 95% confidence interval (CI) (P &amp;gt; 0.5), furthermore A cutoff ADC point of ≤ 2.26 x10 − 3 mm2/s can be considered as diagnostic threshold for malignant cystic renal lesion lesions (among all study cases) with 87.5% sensitivity, 87.2% specificity, 70.0% PPV, 95.3% NPV, opposite to 100% sensitivity, 82.9% specificity, 66.7% PPV, 100% NPV for the CE-MRI. AUC for CE-MRI (0.976) and DW-MRI (0.917) in the differentiation between benign and malignant lesions (after exclusion of renal abscess and renal hemorrhagic cysts from study cases) were within corresponding 95% confidence interval (CI) (P = &amp;gt;0.5), A cutoff ADC point of ≤ 2.84 x10 − 3 mm2/s could be considered as diagnostic threshold for malignant cystic renal lesion lesions (after exclusion of renal abscess and renal hemorrhagic cysts from study cases) with 93.7% sensitivity, 91.9% specificity, 83.3 PPV, 97.1 NPV, opposite to 100% sensitivity, 95.12% specificity, 88.9% PPV, 100% NPV for the CE-MRI. Conclusions Our study showed that malignant cystic renal masses had tendency toward restricted diffusivity and significant lower ADCs in comparison to benign ones, and diagnostic performance of DWI-ADC at b-value of 0-400-800 s/mm2 appeared as efficient as that of CE-MRI in differential between benign and malignant cystic lesions, especially when usage of contrast medium is contraindicated, however there is noticeable ADC overlapping among some malignant and benign lesions, specifically for renal carcinomas versus renal abscesses as well as for renal cell carcinoma versus renal hemorrhagic cysts, For such situation we need to consider clinical data, follow up notes, and correlates with findings of conventional MRI to optimize the characterization of cystic renal lesion before establishment of proper management plan.

Diagnostic performance of a 3D double-echo steady-state sequence at 3 T using radial reformats for detecting and grading rotator cuff tears: a pilot diagnostic accuracy study with magnetic resonance imaging and arthroscopic correlation.

In diagnosing rotator cuff tears (RCTs), magnetic resonance imaging (MRI) is the imaging modality of choice, and its accuracy is improving constantly. To evaluate the diagnostic performance of a high-resolution 3D double-echo steady-state (DESS) sequence with radial and paracoronal 3-T MRI regarding the grading of RCTs in correlation with conventional 2D MRI and arthroscopic findings. We retrospectively compared arthroscopic findings of RCTs with preoperative MRI, including conventional 2D sequences and radial and paracoronal DESS images in 20 patients. Two observers evaluated supraspinatus (SSP), infraspinatus (ISP), and subscapularis (SSC) tendon tears using a grading system. For statistical analysis, arthroscopy was used as the reference standard. Inter-observer agreement for detecting and grading SSP, ISP, and SSC tendon tears on radial and paracoronal sliced 3D DESS MRI was excellent (intraclass-correlation [ICC] = 0.92-0.98; all P < 0.001). Regarding the detection of SSP lesions, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 93.8%, 50%, 88.2%, and 66.7% for both radial and paracoronal DESS imaging. A sensitivity of 100%, specificity of 61.1%, PPV of 22.2%, and NPV of 100% were noted for detecting ISP tendon tears using radially reformatted DESS images. Regarding detecting SSC tendon tears using radially reformatted DESS images, sensitivity, specificity, PPV, and NPV were 100%, 81.3%, 50%, and 100%, respectively. The results with standard 2D MRI were similar. The DESS technique with radially reformatted images provided excellent sensitivity and high inter-observer agreement in detecting RCTs. It showed a moderate to high correlation between MRI and arthroscopy for diagnosing SSP and SSC tendon tears.

A Prospective Study to Evaluate the Clinical and Diffusion Tensor Imaging (DTI) Correlation in Patients with Lumbar Disc Herniation with Radiculopathy.

Conventional magnetic resonance imaging findings frequently do not correlate with the symptoms of lumbar disc herniation (LDH). Diffusion-weighted imaging can reveal important details about the microstructure of tissues. This study assessed the role of diffusion-weighted imaging (DTI) in LDH with radiculopathy and explored the relationship between DTI values and clinical scores. Forty-five patients with LDH with radiculopathy were evaluated via DTI at the intraspinal (IS), intraforaminal (IF), and extraforaminal (EF) levels. A visual analog scale (VAS) was used for low back and leg pain. The Japanese Orthopaedic Association (JOA) scoring system, Oswestry Disability Index (ODI), and Roland-Morris Disability Questionnaire (RMDQ) were used for functional evaluation. There was a statistically significantly (p<0.05) difference between the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values on the affected side compared with those on contralateral normal side. The VAS score had a weak positive correlation with RMDQ score (r=0.279, P=0.050). The JOA score had a moderate negative correlation with RMDQ score (r=-0.428, P=0.002), whereas the ODI score had a moderate positive correlation with RMDQ score (r=0.554, P<0.001). There was a moderate positive correlation between ADC values at the IF level and the RMDQ score on the affected side (r=0.310, P=0.029). There was no correlation between FA values and JOA score. ODI had a significantly positive correlation with the contralateral normal side FA values at the IF (r=0.399, P=0.015), EF (r=0.368, P=0.008) and IS (r=0.343, P=0.015) levels. RMDQ had a weak positive correlation with the contralateral normal side FA values at the IF (r=0.311, P=0.028), IS (r=0.297, P=0.036) and EF (r=0.297, P=0.036) levels. The decrease in FA values and the increase in ADC values are useful markers of compression. ADC correlates well with the patient's neurological symptoms and functional status. Conversely, FA correlates well with the patient's neurological symptoms, but is not correlated well with the functional status.

Accuracy of apparent diffusion coefficient values for distinguishing between pineal germ cell tumour and pineoblastoma

To differentiate between pineal germ cell tumour and pineoblastoma using apparent diffusion coefficient (ADC) values due to their overlapping imaging findings on magnetic resonance imaging (MRI). This retrospective study was conducted on 33 patients with pineal germ cell tumours and eight patients with pineoblastoma who underwent pretreatment MRI. Twenty-seven patients (21 with pineal germ cell tumour and six with pineoblastoma) were included for ADC measurement. The minimum and mean ADC values of the tumours were measured, with normalized tumour to control ADC ratios generated. The MRI characteristics of the tumours were evaluated. The mean and minimum ADC values, normalized mean and minimum ADC ratios of pineal germ cell tumours were significantly higher than those of pineoblastomas (all p<0.005). A cut-off value of 0.92 for the normalized mean ADC ratio was used to distinguish between pineal germ cell tumour and pineoblastoma and achieved an area under the curve of 0.95, sensitivity of 90.5%, specificity of 83.3%, and accuracy of 92.6%. An equal degree of contrast enhancement to the adjacent venous sinus was the only MRI characteristic that suggested the diagnosis of pineal germ cell tumour. The ADC values could help differentiate between pineal germ cell tumour and pineoblastoma, specifically when conventional MRI findings are indeterminate.

Effectiveness of ADC histogram analysis in the diagnosis of focal liver lesions; is a contrast agent necessary?

Objective: The diagnostic success of apparent diffusion coefficient (ADC) histogram analysis in focal liver lesions, and the effects of quantitative data added to contrast-enhanced abdominal magnetic resonance imaging (MRI) on the diagnostic accuracy were investigated. Materials and Methods: The conventional MRI findings of 524 lesions in total were retrospectively examined. Contrast enhancement kinetics and ADC values for each lesion were found through an image analysis software. Results: Three hundred and fifty (67%) of the lesions were diagnosed as benign and 174 (33%) as malignant. Statistically significant difference was found between the benign and malignant lesion groups in terms of the minimum, maximum and mean ADC values (p&amp;lt;0.001). When optimal thresholds for minimum, maximum and mean ADC were taken as 1.47x10-3mm2/s; 1.85x10-3mm2/s; 1.72x10-3mm2/s respectively, sensitivity was found to be 97%; 83%; 95%, specificity was 100%; 98%; 99%, NPV was 100%; 99%; 99%, and PPV was 93%; 74%; 90%. ADC values added to MRI increased the diagnostic success for metastases (92%→96%), HCC (63%→73%), hemangioma (90%→99%) and FNH (56%→75%). Conclusion: ADC measurement could not show reasonable success in the diagnosis of specific lesions while being successful in the differentiation of benign and malignant lesions. Minimum ADC is more successful than mean and maximum ADC. A non-contrastenhanced MRI protocol based on the ADC measurement applicable to the selected patient group may be helpful.

Conventional and advanced MR imaging findings in a cohort of pathology-proven dermoid cysts of the pediatric scalp and skull.

In the pediatric population, dermoid cysts are among the most frequent lesions of the scalp and skull. Imaging plays a key role in characterizing scalp and skull lesions in order to narrow the differential diagnoses. In general, dermoids are described as heterogeneous T1-/T2-hypo- to hyperintense lesions on magnetic resonance imaging. The goal of this retrospective study is to evaluate the diffusion weighted imaging findings while reviewing the conventional T1-/T2-/T1+C-weighted MR characteristics in a pathology-proven series of 14 dermoids of the pediatric scalp and skull. In our pediatric cohort (eight boys, six girls, age range 3-95 months), half of the dermoids were homogeneous T1-hypointense and homogeneous T2-hyperintense. We found a mixture of restricted (45.5%) and increased diffusion (54.5%) in dermoids. The vast majority of dermoids (91.7%) showed rim enhancement. Most dermoids (57.1%) were located at the midline and adjacent to one of its sutures. This study suggests that dermoids may have more variable imaging appearances than hitherto assumed and are frequently seen in close proximity or adjacent to the anterior fontanelle.

MRI Spectrum of Japanese Encephalitis in Northeast India: A Cross-Sectional Study.

Objective Japanese encephalitis (JE) is an arthropod-borne flavivirus infection having high mortality and morbidity. This study was performed to evaluate the conventional magnetic resonance imaging (MRI) findings in JE and to find out any difference between pediatric and adult JE. Materials and Methods This retrospective study was performed on serologically positive 54 JE patients presented to a tertiary care hospital with acute encephalitic symptoms between April 2016 and October 2019. Relevant neurological examination, cerebrospinal fluid analysis, and MRI scan of the brain were performed. Results Fifty-four JE patients ( n = 31 males and n = 23 females) having 32 pediatric and 22 adult JE were included in the study sample. Group 1 JE ( n = 16) patients had encephalitic symptoms with duration less than 15 days up to the day of MRI scan and group 2 JE ( n = 38) had symptoms more than 15 days. Group 1 JE had mean apparent diffusion coefficient (ADC) value of 0.563 ± 0.109 (standard deviation [SD]) × 10 –3 mm 2 /sec and group 2 JE had 1.095 ± 0.206 (SD) × 10 –3 mm 2 /sec. The mean ADC value of pediatric JE was 0.907 ± 0.336 (SD) × 10 –3 mm 2 /sec and adult JE was 0.982 ± 0.253 (SD) × 10 –3 mm 2 /sec. Conclusion The majority of the JE patient shows abnormal signal alterations in bilateral thalami and substantia nigra. Diffusion-weighted imaging with ADC mapping helps in evaluating the stage of the JE. No statistical significance of the various conventional MRI findings was found between the pediatric JE and adult JE.

Correlation of Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy of Basal Ganglia with APGAR Score in Perinatal Asphyxia: A Cross-sectional Study

Introduction: Birth asphyxia is leading cause of perinatal and neonatal mortality and morbidity especially in developing countries. Around 20% of neonatal deaths in India are due to birth asphyxia. There are around one million cases of birth asphyxia per year worldwide. Majority of deaths and disabilities can be prevented by timely identification of pathologies and early initiation of rehabilitation. Magnetic Resonance Imaging (MRI) and Magnetic Resonance Spectroscopy (MRS) plays a vital role by helping in identification of such pathologies. Aim: To assess the severity of injury to brain in hypoxic ischaemic encephalopathy infants using MRI and MRS which helps in prognosticating the disease outcome. Materials and Methods: A cross-sectional study was conducted on 30 term infants with low Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) score in the Department of Radiodiagnosis, from all the Hospitals attached to Bangalore Medical College and Research Institute, Bengaluru, Karnataka, India from November 2018 to May 2020. Patients were subjected to brain MRI and basal ganglia MRS. All MR imaging examinations were performed on a SIEMENS magneto Avanto 1.5 Tesla system. Conventional MR imaging findings were documented and MR spectroscopy values of Basal Ganglia (BG) N-Acetyl Aspartate (NAA), Creatinine (Cr), Choline (Cho) and lactate were obtained. Metabolite levels were correlated with APGAR scores by performing Pearson correlation. Chi-square test was applied with Fisher’s-exact correction to see the association between lactate peak and diffusion changes in brain. Results: A total of 30 term neonates with low APGAR score at birth were selected, of which 12 were females and 18 were males. Babies with APGAR score of 2 at one minute showed only subcortical and parasagittal areas of diffusion restriction. Basal ganglia diffusion restriction is noted only in babies with very low APGAR score of 1 at one minute. Positive correlation was noted between APGAR score and BG-NAA and BG-Cr. Negative correlation was noted between BG-Cho and APGAR score. Hence, BG-NAA:Cr, NAA:Cho and Cho:Cr can be used to assess severity of hypoxic ischaemic encephalopathy (p-value &lt;0.001). Conclusion: Basal ganglia is a sensitive region in defining asphyxia related metabolite abnormalities. Involvement of basal ganglia and thalamus indicates severe asphyxia. BG metabolite levels may alter even in the absence of brain changes on MR imaging. Presence of lactate peak indicates severe asphyxia. Thus, MRS helps in early diagnosis of birth asphyxia, grading of its severity and prognostication.

Conventional and Diffusion-Weighted MR Imaging Findings of Parotid Gland Tumors.

To investigate diffusion-weighted magnetic resonance imaging (MRI) findings of parotid gland lesions in addition to conventional MRI findings and demographic data. A retrospective evaluation was made of the demographic data, histopathologic data, preoperative conventional and diffusion-weighted MRI of 74 patients who underwent parotidectomy. The patients were categorized according to the histopathology (pleomorphic adenoma [PA], Warthin's Tumor [WT] and malignant Tumor [MT]). Histologically, 30 patients had PA, 27 patients had WT, and the remaining 17 patients had MT. The mean age of the PA, WT and MT groups were 44±21 (20-72), 55±10 (41-71) and 62±20 (21-76) years, respectively. The WT (81%) and MT (70%) groups were male dominant, while the PA group showed female dominance (55%). The PA group showed statistically significant difference in terms of age (p<0.05) and gender (p=0.009) compared to the other two groups. The median apparent diffusion coefficient (ADC) values for the PA, WT and MT groups were 1.99±0.94 (1.10-2.41) × 10-3 mm2/s, 0.92±0.35 (0.21-1.79) × 10-3 mm2/s and 1.20±0.34 (0.78-1.47) × 10-3 mm2/s, respectively. PA was differentiated from the other two groups (p=0.001). The sensitivity and specificity for distinguishing PAs from WT was 97% and 85%, respectively, when the ADC cutoff value was 1.25; and for distinguishing PAs from MT was 77% and 83%, respectively, when the ADC cutoff value was 1.35. ADC measurements are useful for the differentiation of PA from both WT and MT; and can be used as a complementary tool to predict the histopathology in the preoperative planning of parotid tumors.

Arterial spin labeling hyperperfusion in seizures associated with non-ketotic hyperglycaemia: is it merely a post-ictal phenomenon?

A 53-year-old chronic uncontrolled diabetic patient presented with one episode of generalized seizures followed by drowsiness and post-ictal confusion. MR imaging at admission revealed left temporal subcortical T2/FLAIR hypointensities with overlying cortical T2/FLAIR hyperintensities and increased perfusion on arterial spin labeling (ASL). Follow-up imaging at 4- and 8-week interval revealed persistent ASL hyperperfusion with significant resolution of conventional MR imaging findings. Delayed persistent ASL hyperperfusion suggests that hyperglycemia-induced increased blood-brain barrier permeability rather than a mere post-ictal phenomenon in non-ketotic hyperglycemia (NKH) and may result in long-term cognitive disturbances.

The role of ADC values within the normal-appearing brain in the prognosis of multiple sclerosis activity during interferon-\u03b2 therapy in the 3-year follow-up: a preliminary report

Predictors of multiple sclerosis (MS) activity during disease-modifying treatment are being extensively investigated. The aim of this study was to assess the prognosis of NEDA (no evidence of disease activity) status during IFN-β (interferon-β) treatment, using apparent diffusion coefficient (ADC) measurements obtained at initial MRI (magnetic resonance imaging). In 87 MS patients treated with IFN-β, ADC values were calculated for 13 regions of normal-appearing white and grey matter (NAWM, NAGM) based on MRI performed with a 1.5 T magnet before (MS0, n = 45) or after one year of therapy (MS1, n = 42). Associations were evaluated between ADC, conventional MRI findings, demographic and clinical factors and NEDA status within the following 3 years using logistic, Cox and multinomial logistic regression models. NEDA rates in the MS0 group were 64.4%, 46.5% and 33.3% after the 1st, 2nd and 3rd year of treatment, respectively and in MS1 patients 71.4% and 48.7% for the periods 1st–2nd and 1st–3rd years of treatment, respectively. ADC values in the NAWM regions contributed to loss of NEDA and its clinical and radiological components, with a 1–3% increase in the risk of NEDA loss (p = 0.0001–0.0489) in both groups. ADC measurements may have an additional prognostic value with regard to NEDA status.

Conventional MR and DW imaging findings of cerebellar primary CNS lymphoma: comparison with high-grade glioma

Primary central nervous system lymphomas (PCNSLs) and high-grade gliomas (HGGs) arising in the cerebellum is extremely low, making the differential diagnosis difficult or even impossible. The purpose of this study was to define the MR features of cerebellar PCNSL in immunocompetent patients, and to determine whether a combination of conventional MR and DW imaging can assist in the differentiation of PCNSLs and HGGs. Twelve PCNSLs and 15 HGGs confirmed by pathological analysis were retrospectively identified. The apparent diffusion coefficient (ADC) and conventional MRI parameters were compared for differences between PCNSL and HGG groups using the independent sample t test or chi-square test. Both ADCmin and ADCtotal values were lower in the PCNSL group than those in the HGG group (ADCmin: 0.53 × 10−3 vs. 0.83 × 10−3 mm2/sec, P < 0.001; ADCtotal: 0.66 × 10−3 vs. 0.98 × 10−3 mm2/sec, P = 0.001). As for conventional MR features, there were significant difference in the tumor size, enhancement patterns, the presence of cystic changes, edema degree and streak-like edema (all P < 0.01); but there were no significant difference in lesion type, the presence of bleeding, and involvement of brain surface between two groups (P = 0.554, 0.657 and 0.157, respectively). The results revealed that several conventional MR features, including enhancement patterns, branch-like enhancement and streak-like edema may be useful for the differentiation of PCNSL and HGG in cerebellum and, when combined with ADC values, further improve the discriminating ability.

Clinical-radiological dissociation in a patient with nitrous oxide-induced subacute combined degeneration: a case report

BackgroundSeveral recent studies have reported subacute combined degeneration (SCD) induced by nitrous oxide (N2O) abuse. However, the association between the evolution of dynamic neuroimaging and clinical manifestations has not been reported in patients with N2O-induced SCD.Case presentationWe described the case of a 24-year-old man who developed SCD with inverted V-sign hyperintensities over the posterior aspect of the spinal cord caused by frequent, excessive N2O inhalation. One month after treatment, his weakness and paresthesia resolved and serum vitamin B12 levels exceeded the normal levels. However, the hyperintensities had extended horizontally and longitudinally on T2-weighted magnetic resonance imaging (MRI), compared to those on the initial scan. Two months after treatment, the patient experienced some residual numbness in the distal limbs, and his serum homocysteine levels were normal, but the abnormal signals seen on cervical T2-weighted MRI had decreased only slightly compared to those seen on the one-month follow-up MRI. The evolution of conventional MRI findings lagged compared to the clinical manifestation, which was suggestive of a clinical-radiological dissociation.ConclusionsClinical-radiological dissociation might have occurred in this case because T2-weighted imaging was not sensitive enough to reveal cytotoxic edema. Moreover, the serum vitamin B12 level is not a good indicator of cellular vitamin B12. Thus, clinicians should recognize this phenomenon, comprehensively assess the condition of patients with N2O-induced SCD, and avoid terminating treatment based on the resolution of clinical symptoms and serological results.

The Specific Magnetic Resonance Imaging Indicators in Predicting Clear-Cell Renal Cell Carcinoma Metastatic to the Sinonasal Region.

The aim of this study was to determine the valuable magnetic resonance imaging (MRI) features of sinonasal metastatic clear-cell renal cell carcinoma (cc-RCC), especially focusing on its dynamic-enhanced characteristics. The conventional and dynamic-enhanced MRI findings of 8 patients with histopathologically confirmed sinonasal metastatic cc-RCC were reviewed by 2 radiologists. The control group of 8 patients with capillary hemangioma underwent the same MRI protocol. Metastatic cc-RCCs arose from the nasoethmoid region, maxillary sinus, posterior ethmoid and sphenoid sinus, and nasal cavity in 2 patients in each. These lesions were well circumscribed and the mean maximum dimension was 42 mm. The signal intensity of these lesions was isointense to brain stem on both MR T1- and T2-weighted images. All metastatic tumors showed vivid enhancement on enhanced T1-weighted image. Multiple flow voids within these metastatic lesions were identified in 6 patients. Peripheral cyst was detected around the metastatic tumor in 4 patients. Metastatic cc-RCCs exhibited a characteristic type 4 time intensity curve (TIC) similar to that of the internal carotid artery, whereas capillary hemangiomas showed a type 3 TIC on dynamic-enhanced MRI. A hypervascular mass with the characteristic type 4 TIC in the sinonasal region is highly suggestive of a metastatic cc-RCC.