Comparison of ASL and DSC perfusion methods in the evaluation of response to treatment in patients with a history of treatment for malignant brain tumor.

OBJECTIVE: Perfusion MRI is of great benefit in the post-treatment evaluation of brain tumors. Interestingly, dynamic susceptibility contrast-enhanced (DSC) perfusion has taken its place in routine examination for this purpose. The use of arterial spin labeling (ASL), a perfusion technique that does not require exogenous contrast material injection, has gained popularity in recent years. The aim of the study was to compare two different perfusion techniques, ASL and DSC, using qualitative and quantitative measurements and to investigate the diagnostic effectiveness of both. The fact that the number of patients is higher than in studies conducted with 3D pseudo-continious ASL (pCASL), the study group is heterogeneous as it consists of patients with both metastases and glial tumors, the use of 3D Turbo Gradient Spin Echo (TGSE), and the inclusion of visual (qualitative) assessment make our study unique. METHODS: Ninety patients, who were treated for malignant brain tumor, were enrolled in the retrospective study. DSC Cerebral Blood Volume (CBV), Cerebral Blood Flow (CBF) and ASL CBF maps of each case were obtained. In qualitative analysis, the lesions of the cases were visually classified as treatment-related changes (TRC) and relapse/residual mass (RRT). In the quantitative analysis, three regions of interest (ROI) measurements were taken from each case. The average of these measurements was compared with the ROI taken from the contralateral white matter and normalized values (n) were obtained. These normalized values were compared across events. RESULTS: Uncorrected DSC normalized CBV (nCBV), DSC normalized CBF (nCBF) and ASL nCBF values of RRT cases were higher than those of TRC cases (p < 0.001). DSC nCBV values were correlated with DSC nCBF (r: 0.94, p < 0.001) and correlated with ASL nCBF (r: 0.75, p < 0.001). Similarly, ASL nCBF was positively correlated with DSC nCBF (r: 0.79 p < 0.01). When the ROC curve parameters were evaluated, the cut-off values were determined as 1.211 for DSC nCBV (AUC: 0.95, 93% sensitivity, 82% specificity), 0.896 for DSC nCBF (AUC; 0.95, 93% sensitivity, 82% specificity), and 0.829 for ASL nCBF (AUC: 0.84, 78% sensitivity, 75% specificity). For qualitative evaluation (visual evaluation), inter-observer agreement was found to be good for ASL CBF (0.714), good for DSC CBF (0.790), and excellent for DSC CBV (0.822). Intra-observer agreement was also evaluated. For the first observer, good agreement was found in ASL CBF (0.626, 70% sensitive, 93% specific), in DSC CBF (0.713, 76% sensitive, 95% specific), and in DSC CBV (0.755, 87% sensitive - 88% specific). In the second observer, moderate agreement was found in ASL CBF (0.584, 61% sensitive, 97% specific) and DSC CBF (0.649, 65% sensitive, 100% specific), and excellent agreement in DSC CBV (0.800, 89% sensitive, 90% specific). CONCLUSION: It was observed that uncorrected DSC nCBV, DSC nCBF and ASL nCBF values were well correlated with each other. In qualitative evaluation, inter-observer and intra-observer agreement was higher in DSC CBV than DSC CBF and ASL CBF. In addition, DSC CBV is found more sensitive, ASL CBF and DSC CBF are found more specific for both observers. From a diagnostic perspective, all three parameters DSC CBV, DSC CBF and ASL CBF can be used, but it was observed that the highest rate belonged to DSC CBV.

Detection and vascular territorial classification of stroke on diffusion-weighted MRI by deep learning.

PURPOSE: Rapid detection and vascular territorial classification of stroke enable the determination of the most appropriate treatment. In this study, we aimed to investigate the performance of convolutional neural network (CNN) models in the detection and vascular territorial classification of stroke on diffusion-weighted images (DWI). METHODS: DWI of 421 cases (271 acute ischemic stroke patients and 150 cases without any ischemia findings on DWI) obtained between January 2017 to April 2020 were reviewed. We created two custom datasets. A stroke detection dataset was created with 1800 slices (900 S and 900 normal) consisting of 1400 for training, 200 for validation, 200 for test. A vascular territorial type dataset was created with 1717 slices (883 middle cerebral artery stroke, 416 posterior circulatory stroke, and 418 watershed stroke) consisting of 1117 slices for training, 300 for validation, 300 for test. A transfer learning approach based on MobileNetV2 and EfficientNet-B0 CNN architecture was used. The performance of the models was evaluated. RESULTS: Modified MobileNetV2 and EfficientNet-B0 models achieved 96% (κ: 0.92) and 93% (κ: 0.86) accuracy in stroke detection, respectively. In vascular territorial classification of stroke as middle cerebral artery, posterior circulation, or watershed infarction, an accuracy of 93% (κ: 0.895) was achieved with modified MobileNetV2 model and 87% (κ: 0.805) with modified EfficientNet-B0 CNN model. CONCLUSION: Transfer learning approach with custom top CNN models achieve sufficiently high performance for both the detection of ischemic stroke and the classification of its vascular territorial type on DWI.

The relationship between patellar tilt and quadriceps patellar tendon angle with anatomical variations and pathologies of the knee joint.

PURPOSE: To investigate the association between the knee joint anatomical variations and pathologies, and to describe the quadriceps patellar tendon angle (QPA). METHODS: MRIs of 406 cases with a lateral patellar tilt angle (LPT)>5° and a control group of 40 cases with an LPT<5° were retrospectively evaluated. QPA, LPT, trochlear sulcus angle (TSA), tibial tubercle-trochlear groove distance (TT-TG), Insall-Salvati index (ISI), patellar tendon length (PTL), patellar height (PH), lateral trochlear inclination (LTI), trochlear facet asymmetry ratio (TFA) and trochlear depth (TD) were measured. Presence of fat-pad oedema, patellar and trochlear chondromalacia, patellar and quadriceps tendinosis and effusion were evaluated. RESULTS: The medians of TSA, PTL, ISI and TT-TG were significantly higher; LTI, TFA and TD were significantly lower in the patient group. The prevalence of SL-Hoffa, non-SL-Hoffa, suprapatellar and prefemoral fat-pad oedema, effusion and chondromalacia were significantly higher in the patient group. LPT was found to be positively correlated with TSA and TT-TG, and negatively correlated with LTI and TD. Cases with trochlear dysplasia, patellar chondromalacia and quadriceps tendinosis had significantly higher LPT. There was a positive correlation between QPA and TSA and a negative correlation between QPA and LTI. Cases with trochlear dysplasia, non-SL-Hoffa oedema, prefemoral fat-pad oedema and quadriceps tendinosis had significantly higher QPA. We found 10°

Assessment of the compliance with minimum acceptable technical parameters proposed by PI-RADS v2 guidelines in multiparametric prostate MRI acquisition in tertiary referral hospitals in the Republic of Turkey.

PURPOSE: Although the clinical use of multiparametric prostate magnetic resonance imaging (mpMRI) is increasing, the adherence to parameters for mpMRI, which had been described in the Prostate Imaging-Reporting and Data System version 2 (PI-RADS v2) for an optimum image acquisition is unknown. In this paper, we aimed to determine the compliance with the minimum acceptable technical parameters for prostate mpMRI defined by PI-RADS v2 in tertiary care centers in Turkey. METHODS: We sent a survey to all radiology departments of tertiary referral hospitals in Turkey (n=120) to evaluate their adherence to PI-RADS v2 technical specifications. Statistical analysis was performed using chi-square, Fisher exact, ANOVA, and the Student t tests. The cutoff values for image acquisition times were also determined with receiver operating characteristics (ROC) analysis. P values <0.05 were considered statistically significant. RESULTS: One hundred and eleven clinics responded to our survey (response rate, 92.5%). Prostate MRI was reported to be performed in 61 centers, of which 26 (42.6%) used 3 T (Tesla) scanner while 35 (57.4%) used 1.5 T. The adherence to slice thickness, in-plane phase and frequency resolutions on T2-weighted imaging were 68.9%, 41%, and 9.8%, respectively. The adherence to the same parameters on diffusion-weighted imaging (DWI) were higher compared with T2-weighted imaging (85.2%, 62.3%, and 78.7%, respectively). In comparative analysis, the adherence to slice thickness, field of view (FOV) and in-plane phase resolution on T2-weighted imaging were higher for 3 T compared with 1.5 T scanners (P = 0.004, P = 0.041, and P = 0.001, respectively). T2-weighted imaging acquisition time was significantly longer for the centers that adhered to FOV (P = 0.034) and in-plane T2-weighted imaging phase resolution (P = 0.028). The DWI scan time was significantly longer when they adhered to DWI-FOV (P = 0.014) and b value ≥1400 s/mm2 (P = 0.008). The calculated cutoff of scan times were 220 s in T2-weighted imaging and 312 s in DWI to ensure the compliance with voxel sizes and b value criteria. CONCLUSION: The tertiary referral centers in Turkey did not meet majority of the technical specifications of PI-RADS v2 during prostate MRI acquisition. Awareness to the minimum acceptable technical parameters of mpMRI should be increased to potentially improve the quality of prostate cancer imaging.

Developmental Venous Anomaly With Asymmetrical Basal Ganglia Calcification: Two Case Reports and Review of the Literature.

Developmental venous anomaly (DVA) is a common lesion formerly known as venous angioma. DVAs drain normal brain parenchyma; however, parenchymal abnormalities surrounding DVAs have been reported. Unilateral putamen and caudate calcification in the drainage territory of DVAs has so far been reported in 7 cases, all with deep venous drainage. We present two additional cases of DVAs, one with superficial and the other one with deep venous drainage, associated with basal ganglia calcifications. We emphasize that DVAs should be in the differential diagnosis of unilateral basal ganglia calcifications.

Reactive changes of disc space and foreign body granuloma due to bone wax in lumbar spine.

Bone wax is a well-known agent used to prevent bleeding from the bone that can be used in different surgical procedures. Bone wax is a safe agent, but it may rarely lead to significant foreign body reactions. In this report, we present a patient who developed bone wax-related disc space foreign body granuloma following L4 total laminectomy, extremely rare complication.

Intracranial chronic subdural haematoma as a complication of epidural anesthesia.

We report the case of a 39-year-old woman with unilateral intracranial chronic subdural haematoma that occurred after epidural anesthesia for excision of a skin scar, complicated by postdural puncture headache. The patient had no history of trauma, headache, coagulation abnormalities, or neurological disorders. Most physicians encountering a case of headache after epidural or spinal anesthesia first think of a postdural puncture headache. Nonetheless, the symptoms subside within 7 days when treated with analgesics and bed rest in the majority of cases. The presence of a continued postdural puncture headache without neurological deterioration, as in this case, should prompt a search for an intracranial lesion.

Unilateral acute foot drop due to diffuse axonal injury after head trauma.

Acute foot drop due to diffuse axonal injury (DAI) has not been previously described in the literature. In this report, we present a patient with unilateral acute foot drop caused by a DAI lesion after head trauma.