Deep learning for assessing image quality in bi-parametric prostate MRI: A feasibility study.

BACKGROUND: Although systems such as Prostate Imaging Quality (PI-QUAL) have been proposed for quality assessment, visual evaluations by human readers remain somewhat inconsistent, particularly among less-experienced readers. OBJECTIVES: To assess the feasibility of deep learning (DL) for the automated assessment of image quality in bi-parametric MRI scans and compare its performance to that of less-experienced readers. METHODS: We used bi-parametric prostate MRI scans from the PI-CAI dataset in this study. A 3-point Likert scale, consisting of poor, moderate, and excellent, was utilized for assessing image quality. Three expert readers established the ground-truth labels for the development (500) and testing sets (100). We trained a 3D DL model on the development set using probabilistic prostate masks and an ordinal loss function. Four less-experienced readers scored the testing set for performance comparison. RESULTS: The kappa scores between the DL model and the expert consensus for T2W images and ADC maps were 0.42 and 0.61, representing moderate and good levels of agreement. The kappa scores between the less-experienced readers and the expert consensus for T2W images and ADC maps ranged from 0.39 to 0.56 (fair to moderate) and from 0.39 to 0.62 (fair to good). CONCLUSIONS: Deep learning (DL) can offer performance comparable to that of less-experienced readers when assessing image quality in bi-parametric prostate MRI, making it a viable option for an automated quality assessment tool. We suggest that DL models trained on more representative datasets, annotated by a larger group of experts, could yield reliable image quality assessment and potentially substitute or assist visual evaluations by human readers.

Does the Application of Platelet-Rich Fibrin in Anterior Cruciate Ligament Reconstruction Enhance Graft Healing and Maturation? A Comparative MRI Study of 44 Cases.

BACKGROUND: Anterior cruciate ligament (ACL) reconstruction performed with growth factors and activated platelets has been suggested to accelerate tendon ligamentization, leading to earlier return to daily activities and sports. HYPOTHESES: Platelet-rich fibrin (PRF) will result in improved graft maturation and healing as evaluated by magnetic resonance imaging (MRI) in patients undergoing hamstring ACL reconstruction. Hemostatic and analgesic properties of PRF will lead to less postoperative blood loss and pain. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A total of 44 patients with isolated ACL injuries who underwent arthroscopic all-inside anatomic single-bundle ACL reconstruction with semitendinosus tendon graft were enrolled. Group 1 included 23 patients who had PRF sprayed to the surface of the graft; group 2 included 21 patients for whom no PRF was used. Patients were discharged after 24 hours and examined for hemarthrosis that needed to be aspirated. MRI was performed at the fifth postoperative month. A blinded radiologist evaluated graft maturation according to its signal intensity and the presence of synovial fluid at the tunnel-graft interface. RESULTS: PRF-treated grafts demonstrated lower MRI signal intensity and less fluid in the graft-tunnel interface as compared with controls for the entire length of the graft. The mean full-length MRI signal intensities were 9.19 versus 16.59 (P = .047) for groups 1 and 2, respectively. Subgroup analysis of the semitendinosus grafts demonstrated a signal intensity of 11.57 versus 23.98 (P = .044) for the proximal third, 9.53 versus 13.83 (P = .237) for the midbody, and 6.48 versus 11.98 (P = .087) for the distal third. Synovial fluid at the graft-tunnel interface was detected in 1 patient in group 1 (4.3%) and 3 patients in group 2 (14.3%; P < .001). Patients in group 1 had significantly less hemarthrosis that needed to be aspirated (P = .003), while postoperative analgesia requirements were similar in both groups (P = .08). No clinical benefit of PRF could be demonstrated in clinical outcomes. CONCLUSION: Application of PRF led to superior graft integration and maturation in the proximal third of the ACL graft. There was no significant difference in MRI signal intensity in the midbody or distal tibial graft. Application of PRF also resulted in significantly lower rates of postoperative hemarthrosis that needed to be aspirated.

Diffusion tensor imaging findings of the brainstem in subjects with tonsillar ectopia.

We aimed to evaluate the differences between apparent diffusion coefficient (ADC), fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) values obtained from different cranial sites in subjects with Chiari I Malformation (CM-I) and borderline tonsillar ectopia (BTE), and to determine correlations between diffusion tensor imaging (DTI) metrics and the severity of tonsillar ectopia. A total of 73 subjects with CM-I and BTE and 35 control underwent MRI and DTI. In our study, ADC values measured from the level of medulla oblongata and the RD values measured in middle cerebellar peduncles, thalamus, and globus pallidus were higher in CM-I patients than in controls. FA values at the medulla oblongata level and AD values at the medulla oblongata and pons level higher in patients with CM-I. ADC and AD values measured at the pons level were higher in BTE subjects than in controls. Compared with BTE, the CM-I subjects' ADC values at the medulla oblongata and AD values at the pons level were higher. In addition, FAs at the pons and medulla oblongata level were higher. At the medulla oblongata level, a positive correlation was observed between ADC and the size of tonsillar ectopia. AD and FA values measured at the level of medulla oblongata and pons were positively correlated with the size of tonsillar ectopia. These findings may be related to the severity of microstructural changes involving neuronal tracts at the brainstem level due to tonsillar ectopia. DTI may be useful in determining the extent of microstructural changes at the tissue level in subjects with tonsillar ectopia.

MRI findings in parosteal osteosarcoma: correlation with histopathology.

PURPOSE: To assess the role of magnetic resonance imaging (MRI), particularly signal intensity changes, in predicting the dedifferentiation of parosteal osteosarcoma, and to evaluate other factors that may affect grading on MRI. MATERIALS AND METHODS: MRI of 12 patients with parosteal osteosarcoma diagnosed on plain radiography were reviewed with regard to size, location, extent, soft tissue component, intramedullary invasion, and signal characteristics. The findings are correlated with histopathologic results. RESULTS: By histopathological examination there were 6 Grade I, 3 Grade II, and 3 Grade III tumors. Average size was 11 cm. All cases had a soft tissue component. Intramedullary extension was evident in 3/6 of the Grade I cases, 2/3 of the Grade II cases, and all (3/3) of the Grade III cases. T1-weighted images revealed lesions of marked hypointensity. Signal intensity on T2-weighted images varied with the presence of necrosis and hemorrhage in relation to size, regardless of the grade of the tumor. Contrast-enhanced images revealed enhancement of the solid components; no enhancement was observed in the necrotic or hemorrhagic parts. CONCLUSION: High and heterogeneous signal on T2-weighted images of Grade I, II, and III tumors is not specific for the dedifferentiated component, due to hemorrhage and necrosis in large masses. Therefore, high signal intensity on T2-weighted images is not always a reliable way to predict the grade of the tumor. Contrast enhanced T1-weighted images can be valuable to show the solid component in the heterogeneous areas on T2-weighted images, and can be useful in guiding the biopsy.

[The diagnostic efficiency of multislice CT virtual bronchoscopy in detecting endobronchial tumors]. / Endobronsiyal tümörlerde çok kesitli BT sanal bronkoskopinin tanisal etkinligi.

In this study, the diagnostic efficiency of virtual bronchoscopy, which is a new and helpful method to conventional fiberoptic bronchoscopy, has been investigated for endobronchial lung tumors and its clinical applications are discussed. 36 patients with clinically suspected lung cancer (28 males, 8 females, mean age 61; range from 39 to 74) underwent multislice computed tomography (MSCT) virtual bronchoscopy and then conventional bronchoscopy on the same day. For all patients, investigators were uninformed about results of conventional bronchoscopy. Sensitivity, specificity, positive and negative predictive values of virtual bronchoscopy were calculated using conventional bronchoscopy results as standard reference values. In 12 patients, conventional bronchoscopy did not show pathologic findings. In 24 cases pathologic findings were detected; mucosal infiltration was observed in three cases, vegetating lesions were detected in 21 cases. Review of these 21 cases demonstrated preocclusive stenosis in five and various degrees of luminal stenosis in 16 cases. All 21 tumoral lesions observed with conventional bronchoscopy were also detected with virtual bronchoscopy. Retrospective evaluation of six lesions visualized with virtual bronchoscopy but not detected with conventional bronchoscopy showed that they consisted of highly viscous mucous secretion. No abnormalities were detected on both conventional and virtual bronchoscopy in six patients. Three mucosal infiltrations observed on conventional bronchoscopy were not visualised on virtual bronchoscopy. The sensitivity of MSCT virtual bronchoscopy was 88% and specificity was 50% which is concordant with the literature. Positive predictive value, negative predictive value and accuracy was found 78%, 66% and 75%, respectively.

Diffusion MR findings in cyclosporin-A induced encephalopathy.

Cyclosporin encephalopathy is a well-known entity, which is clinically characterized by altered mental status, vision problems, focal neurological deficits and seizures. The exact pathophysiology of the cyclosporin encephalopathy has not yet been defined. We report the diffusion-weighted MR imaging and proton MR spectroscopy findings in a case of cyclosporin encephalopathy. The white-matter lesions with reversible restricted diffusion supported the hypothesis of reversible vasospasm induced by the cyclosporin.