Multi-parametric MRI-based radiomics signature for preoperative prediction of Ki-67 proliferation status in sinonasal malignancies: a two-centre study.

OBJECTIVE: To assess the predictive ability of a multi-parametric MRI-based radiomics signature (RS) for the preoperative evaluation of Ki-67 proliferation status in sinonasal malignancies. METHODS: A total of 128 patients with sinonasal malignancies that underwent multi-parametric MRIs at two medical centres were retrospectively analysed. Data from one medical centre (n = 77) were used to develop the predictive models and data from the other medical centre (n = 51) constitute the test dataset. Clinical data and conventional MRI findings were reviewed to identify significant predictors. Radiomics features were determined using maximum relevance minimum redundancy and least absolute shrinkage and selection operator algorithms. Subsequently, RSs were established using a logistic regression (LR) algorithm. The predictive performance of RSs was assessed using calibration, decision curve analysis (DCA), accuracy, and AUC. RESULTS: No independent predictors of high Ki-67 proliferation were observed based on clinical data and conventional MRI findings. RS-T1, RS-T2, and RS-T1c (contrast enhancement T1WI) were established based on a single-parametric MRI. RS-Combined (combining T1WI, FS-T2WI, and T1c features) was developed based on multi-parametric MRI and achieved an AUC and accuracy of 0.852 (0.733-0.971) and 86.3%, respectively, on the test dataset. The calibration curve and DCA demonstrated an improved fitness and benefits in clinical practice. CONCLUSIONS: A multi-parametric MRI-based RS may be used as a non-invasive, dependable, and accurate tool for preoperative evaluation of the Ki-67 proliferation status to overcome the sampling bias in sinonasal malignancies. KEY POINTS: • Multi-parametric MRI-based radiomics signatures (RSs) are used to preoperatively evaluate the proliferation status of Ki-67 in sinonasal malignancies. • Radiomics features are determined using maximum relevance minimum redundancy (mRMR) and least absolute shrinkage and selection operator (LASSO) algorithms. • RSs are established using a logistic regression (LR) algorithm.

Practical value of three-dimensional high resolution magnetic resonance Vessel Wall imaging in identifying suspicious intracranial vertebrobasilar dissecting aneurysms.

BACKGROUND: Direct evidence of intimal flaps, double lumen and intramural haematomas (IMH) is difficult to detect on conventional angiography in most intracranial vertebrobasilar dissecting aneurysms (VBDAs). Our purpose was to assess the value of three-dimensional high-resolution magnetic resonance vessel wall imaging (3D HRMR VWI) for identifying VBDAs. METHODS: Between August 2013 and January 2016, consecutive patients with suspicious VBDAs were prospectively enrolled to undergo catheter angiography and VWI (pre- and post-contrast). The lesion was diagnosed as definite VBDA when presenting direct signs of dissection; as possible when only presenting indirect signs; and as segmental ectasia when there was local dilation and wall thickness similar to adjacent normal artery's without mural thrombosis. RESULTS: Twenty-one patients with 27 lesions suspicious for VBDAs were finally included. Based on findings of VWI and catheter angiography, definite VBDA was diagnosed in 25 and 7 lesions (92.6%, vs 25.9%, p <  0.001), respectively; possible VBDA in 0 and 20 (0 vs 74.1%), respectively; and segmental ectasia in 2 and 0 (7.4% vs 0%), respectively. On VWI and catheter angiography, intimal flap was detected in 21 and 7 lesions (77.8% vs 25.9%, p = 0.001), respectively; double lumen sign in 18 and 7 (66.7% vs 25.9%, p = 0.003), respectively; and IMH sign in 14 and 0 (51.9% vs 0), respectively. CONCLUSIONS: 3D HRMR VWI could detect direct dissection signs more frequently than catheter angiography. This may help obtain definite diagnosis of intracranial VBDAs, and allow accurate differentiation between dissecting aneurysm and segmental ectasia as well. Further prospective study with larger sample was required to investigate the superiority of HRMR VWI for definite diagnosis of intracranial VBDAs than catheter angiography.

Interactive effect of susceptibility-diffusion mismatch and recanalization status on clinical outcome in large vessel occlusion stroke.

OBJECTIVE: To investigate the interactive effect of susceptibility-diffusion mismatch and recanalization status on clinical outcome in patients with acute ischemic stroke due to large vessel occlusion. METHODS: In this prospective study, consecutive ischemic stroke patients admitted within 24 h from symptom onset underwent emergency multimodal MRI at admission, including diffusion-weighted imaging (DWI), susceptibility-weighted imaging (SWI), and time-of-flight magnetic resonance angiography (TOF-MRA). Patients with large vessel occlusion within the anterior circulation were recruited. Follow-up MRI was performed within 24 h after recanalization therapy (intravenous thrombolysis, endovascular therapy, or both). Multivariable logistic regression analysis was performed to estimate the interaction between SWI-DWI mismatch score and recanalization status on clinical outcome. RESULTS: A total of 90 patients were enrolled. A multiplicative interaction between SWI-DWI mismatch score and recanalization status on clinical outcome was observed (P=0.037). The interaction term "SWI-DWI mismatch score × successful recanalization" was significantly associated with favorable outcome (modified Rankin Scale score of 0-2 at 90 days; adjusted odds ratio [aOR], 2.162; 95% confidence interval [CI], 1.046-4.468). Stratified analysis showed that the likelihood of favorable outcome increased with the increase of SWI-DWI mismatch score in the successful recanalization group (OR, 2.140; 95% CI, 1.376-3.326), while there was no significant relationship between SWI-DWI mismatch score and clinical outcome in the unsuccessful recanalization group (OR, 1.212; 95% CI, 0.933-1.574). CONCLUSIONS: The effects of SWI-DWI mismatch and recanalization status on clinical outcome were realized through their interaction. In anterior circulation stroke due to large vessel occlusion, patients with both high SWI-DWI mismatch scores and successful recanalization were more likely to achieve a favorable outcome, while patients with unsuccessful recanalization, or with successful recanalization but low SWI-DWI mismatch scores, were less likely to have a good prognosis.

Delay-sensitive and delay-insensitive deconvolution perfusion-CT: similar ischemic core and penumbra volumes if appropriate threshold selected for each.

INTRODUCTION: Perfusion-CT (PCT) processing involves deconvolution, a mathematical operation that computes the perfusion parameters from the PCT time density curves and an arterial curve. Delay-sensitive deconvolution does not correct for arrival delay of contrast, whereas delay-insensitive deconvolution does. The goal of this study was to compare delay-sensitive and delay-insensitive deconvolution PCT in terms of delineation of the ischemic core and penumbra. METHODS: We retrospectively identified 100 patients with acute ischemic stroke who underwent admission PCT and CT angiography (CTA), a follow-up vascular study to determine recanalization status, and a follow-up noncontrast head CT (NCT) or MRI to calculate final infarct volume. PCT datasets were processed twice, once using delay-sensitive deconvolution and once using delay-insensitive deconvolution. Regions of interest (ROIs) were drawn, and cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) in these ROIs were recorded and compared. Volume and geographic distribution of ischemic core and penumbra using both deconvolution methods were also recorded and compared. RESULTS: MTT and CBF values are affected by the deconvolution method used (p < 0.05), while CBV values remain unchanged. Optimal thresholds to delineate ischemic core and penumbra are different for delay-sensitive (145 % MTT, CBV 2 ml × 100 g(-1) × min(-1)) and delay-insensitive deconvolution (135 % MTT, CBV 2 ml × 100 g(-1) × min(-1) for delay-insensitive deconvolution). When applying these different thresholds, however, the predicted ischemic core (p = 0.366) and penumbra (p = 0.405) were similar with both methods. CONCLUSION: Both delay-sensitive and delay-insensitive deconvolution methods are appropriate for PCT processing in acute ischemic stroke patients. The predicted ischemic core and penumbra are similar with both methods when using different sets of thresholds, specific for each deconvolution method.

[Brown syndrome: clinical and radiological correlation].

OBJECTIVE: Brown syndrome is characterized by limitation of elevation in adduction, with complex mechanisms involving muscle, tendon, and trochlea. Here, we investigated mechanisms of Brown syndrome by magnetic resonance (MR) imaging. METHODS: It was a retrospective case series study. Fourteen patients with unilateral Brown syndrome between 3 and 54 years of age (10 cases of congenital and 4 cases with acquired disease) were included in the study. All patients underwent complete ophthalmic and orthoptic evaluation. Imaging of the ocular motor nerves at the brainstem was performed on 3D-FIESTA sequence, the orbits were imaged with FSE T1, T2WI using surface coils. RESULTS: Nine of 10 with congenital Brown syndrome demonstrated hypoplasia of the superior oblique (SO) of the affected side. Abnormal low signal intensity in the trochlea area was found in one patient. Three of 4 acquired patients had a history of trauma and were demonstrated fracture of the trochlea, extensive scarring, and superior orbital fracture. One acquired case was demonstrated scarring of anterior part of the SO and hypoplasia of the posterior part. CONCLUSION: Brown syndrome consists of a series of diseases. Their clinical features are quite similar while their anatomical mechanism varies in numerous ways. Therefore, based on patient's individual pathophysiology, the management in Brown syndrome should be personalized.

Influence of chronic hyperglycemia on cerebral microvascular remodeling: an in vivo study using perfusion computed tomography in acute ischemic stroke patients.

BACKGROUND AND PURPOSE: To investigate the effect of chronic hyperglycemia on cerebral microvascular remodeling using perfusion computed tomography. METHODS: We retrospectively identified 26 patients from our registry of 2453 patients who underwent a perfusion computed tomographic study and had their hemoglobin A1c (HbA1c) measured. These 26 patients were divided into 2 groups: those with HbA1c>6.5% (n=15) and those with HbA1c≤6.5% (n=11). Perfusion computed tomographic studies were processed using a delay-corrected, deconvolution-based software. Perfusion computed tomographic values were compared between the 2 patient groups, including mean transit time, which relates to the cerebral capillary architecture and length. RESULTS: Mean transit time values in the nonischemic cerebral hemisphere were significantly longer in the patients with HbA1c>6.5% (P=0.033), especially in the white matter (P=0.005). Significant correlation (R=0.469; P=0.016) between mean transit time and HbA1c level was observed. CONCLUSIONS: Our results from a small sample suggest that chronic hyperglycemia may be associated with cerebral microvascular remodeling in humans. Additional prospective studies with larger sample size are required to confirm this observation.

Association of Homocysteine Levels With Medial Temporal Lobe Atrophy Among Carriers and Non-carriers of APOE ε4 in MCI Subjects.

Background: Different clinical subtypes of mild cognitive impairment (MCI) involve heterogeneous underlying etiologies. This study investigated the association between demographics, neuropsychological performance, apolipoprotein E (APOE) genotype and magnetic resonance imaging (MRI) measures in patients with MCI (amnestic [aMCI] and non-amnestic [naMCI]). Methods: This case-control study included 130 aMCI patients, 58 naMCI patients, and 1,106 healthy controls (HCs). APOE genotypes, medial temporal lobe atrophy (MTA), neurological evaluation results, and white matter hyperintensities (WMH) were investigated. Serum folate and vitamin B12 concentrations were analyzed by radioimmunoassay, and plasma hyperhomocysteinemia (Hcy) was assessed by a high-performance liquid chromatography-fluorescence method. Results: Serum folate levels were significantly lower, but plasma Hcy levels were higher, in patients with aMCI and naMCI than in healthy controls. There were significantly higher MTA scores in the aMCI group than the healthy control group. Multiple linear regression showed that serum Hcy and folate concentrations were positively associated with MTA (p < 0.05), while APOE4 showed a significant negative association with MTA in the aMCI group (p < 0.01). In addition, moderate/severe WMH showed a significant negative association with MTA in the naMCI and HC groups (p < 0.01). Conclusion: The combined presence of APOE4 and Hcy is associated with aMCI in elderly individuals, while moderate/severe WMH is related to naMCI, which suggests etiological differences across MCI subtypes.

Significant improvement of procedural safety in stenting for basilar stenosis: A historically controlled study.

The basilar artery has the most perioperative complications in stenting compared to the other intracranial arteries. We aim to study whether the procedural safety in stenting for basilar stenosis has improved. This study was a single-arm, non-randomized trial that included historically controlled patients for comparison. Between January 2012 and March 2019, 147 consecutive patients with symptomatic basilar stenoses receiving elective stenting treatment were included in current basilar artery stenting (BAS) group. The prospectively collected and registered 120 patients by the same interventional team from September 2001 to November 2011 were set as historical BAS group for control. A total of 267 individuals were included in this study, with a mean age of 59.5 ±â€…8.1 years. The proportion of patients with lesion length >15 mm was 26.5% (39/147) in the current BAS group versus 4.2% (5/120) in the historical BAS group. We found significant differences between these 2 groups in Mori A (17.7% vs 42.5%) and Mori C patients (42.9% vs 13.3%). The proportion of patients receiving preoperative high-resolution magnetic resonance (HRMRI) evaluation was 83.0% (122/147) in the current BAS group versus 20.8% (25/120) in the historical group (P < .05). Balloon-expendable stent (BES) (n = 1), Wingspan (n = 34), and Enterprise (n = 112) stents were placed in the current BAS group. In contrast, only balloon-expendable stent (BES) (n = 48) and Wingspan (n = 72) were deployed in the historical BAS group. The incidence of the safety endpoint (SE) was 4.1% (involving 6 patients) in the current BAS group versus 11.7% (involving 14 patients) in the historical BAS group (P < .05). In multivariate analysis, no risk factor was associated with the occurrence of the safety endpoint (SE). When BAS cases operated by the surgical team accumulated to 120 to 150, the incidence of complications decreased significantly. This is the largest sample size study to discuss the safety of BAS. The significantly decreased incidence of complications indicates that the improving technical measures and the accumulation of operation experience are necessary.

MRI radiomic features-based machine learning approach to classify ischemic stroke onset time.

PURPOSE: We aimed to investigate the ability of MRI radiomics features-based machine learning (ML) models to classify the time since stroke onset (TSS), which could aid in stroke assessment and treatment options. METHODS: This study involved 84 patients with acute ischemic stroke due to anterior circulation artery occlusion (51 in the training cohort and 33 in the independent test cohort). Region of infarct segmentation was manually outlined by 3D-slicer software. Image processing including registration, normalization and radiomics features calculation were done in R (version 3.6.1). A total of 4312 radiomic features from each image sequence were captured and used in six ML models to estimate stroke onset time for binary classification (≤ 4.5 h). Receiver-operating characteristic curve (ROC) and other parameters were calculated to evaluate the performance of the models in both training and test cohorts. RESULTS: Twelve radiomics and six clinic features were selected to construct the ML models for TSS classification. The deep learning model-based DWI/ADC radiomic features performed the best for binary TSS classification in the independent test cohort, with an AUC of 0.754, accuracy of 0.788, sensitivity of 0.952, specificity of 0.500, positive predictive value of 0.769, and negative predictive value of 0.857, respectively. Furthermore, adding clinical information did not improve the performance of the DWI/ADC-based deep learning model. The TSS prediction models can be visited at: http://123.57.65.199:3838/deeptss/ . CONCLUSIONS: A unique deep learning model based on DWI/ADC radiomic features was constructed for TSS classification, which could aid in decision making for thrombolysis in patients with unknown stroke onset.

[Vertical retraction syndrome caused by anomalous orbital structures].

OBJECTIVE: To described the clinical feature and MRI imaging of six children with vertical retraction syndrome. METHODS: Six children with unilateral vertical retraction syndrome between 15 months and 8 years of age, mean age was (5.01 ± 1.27) years old. Strabismus examination included diopter, prism diopters, eye movement examination, binocular vision and fundus examination. Imaging of the ocular motor nerves at the brainstem was performed in 0.8 mm thickness image planes using 3D-FIESTA sequence, the orbits were imaged with FSE T1, T2WI using surface coils, and within 2.0 mm thick planes. RESULTS: Four children showed hypertropia, characterized by limited depression, a light retraction of the globe during downward gaze and eyelid lag. The MRI imaging showed anomalous orbital structure in the superonasal quadrant that between medial rectus and superior rectus or adjacent to the superior rectus. Two children showed intermittent exotropia, characterized by limited elevation, retraction of the globe and narrowing of the palpebral fissure during upward gaze. The MRI imaging showed anomalous orbital structure was present in the inferotemporal quadrant, one originate in inferior rectus and another close to the lateral rectus. CONCLUSION: Anomalous orbital structures are a main cause of vertical retraction syndrome. The presence of specific unusual eye movement and MRI imaging may assist in diagnosis. When the eyelid lag was found since the early age, anomalous orbital structures were implied.

Imaging Manifestations and Evaluation of Postoperative Complications of Bone and Joint Infections under Deep Learning.

To explore and evaluate the imaging manifestations of postoperative complications of bone and joint infections based on deep learning, a retrospective study was performed on 40 patients with bone and joint infections in the Department of Orthopedics of Orthopedics Hospital of Henan Province of Luoyang City. Sensitivity and Dice similarity coefficient (DSC) were used to evaluate the image results by convolutional neural network (CNN) algorithm. Imaging features of postoperative complications in 40 patients were analyzed. Then, three imaging methods were used to diagnose the features. Sensitivity and specificity were used to evaluate the diagnostic performance of three imaging methods for imaging features. Compared with professional doctors and biomarker algorithms, the sensitivity of CNN algorithm proposed was 90.6%, and DSC was 84.1%. Compared with traditional methods, the CNN algorithm has higher image resolution and wider and more accurate lesion area recognition and division. The three manifestations of soft tissue abscess, periosteum swelling, and bone damage were postoperative imaging features of bone and joint infections. In addition, compared with X-ray, CT examination and MRI examination were better for the examination of imaging characteristics. CT and MRI had higher sensitivity and specificity than X-ray. The experimental results show that CNN algorithm can effectively identify and divide pathological images and assist doctors to diagnose the images more efficiently in clinic.

Susceptibility-diffusion mismatch correlated with leptomeningeal collateralization in large vessel occlusion stroke.

OBJECTIVE: To investigate the relationship between asymmetric prominent hypointense vessels (prominent vessel sign, PVS) on susceptibility-weighted imaging (SWI) and leptomeningeal collateralization in patients with acute ischemic stroke due to large vessel occlusion. METHODS: We retrospectively enrolled patients with M1 segment occlusion of the middle cerebral artery who underwent emergency magnetic resonance imaging and digital subtraction angiography within 24 hours from stroke onset. The extent of PVS on SWI was assessed using the Alberta Stroke Program Early CT Score (ASPECTS). Leptomeningeal collateralization on digital subtraction angiography images was assessed using the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) scale. Spearman's rank correlation test was performed to explore the correlation of ASITN/SIR scores with SWI-ASPECTS and SWI-diffusion-weighted imaging (DWI) mismatch scores. RESULTS: Thirty-five patients were enrolled. There was no significant correlation between SWI-ASPECTS and ASITN/SIR scores. However, SWI-DWI mismatch scores were positively correlated with ASITN/SIR scores. CONCLUSION: The range of PVS on SWI did not closely reflect the collateral status, while the range of SWI-DWI mismatch was significantly correlated with the leptomeningeal collateralization. In patients with acute anterior circulation stroke due to large vessel occlusion, larger SWI-DWI mismatch was associated with better leptomeningeal collaterals.

Factors associated with prominent vessel sign on susceptibility-weighted imaging in acute ischemic stroke.

The prominent vessel sign (PVS) on susceptibility-weighted imaging (SWI) is not displayed in all cases of acute ischemia. We aimed to investigate the factors associated with the presence of PVS in stroke patients. Consecutive ischemic stroke patients admitted within 24 h from symptom onset underwent emergency multimodal MRI at admission. Associated factors for the presence of PVS were analyzed using univariate analyses and multivariable logistic regression analyses. A total of 218 patients were enrolled. The occurrence rate of PVS was 55.5%. Univariate analyses showed significant differences between PVS-positive group and PVS-negative group in age, history of coronary heart disease, baseline NIHSS scores, total cholesterol, hemoglobin, anterior circulation infarct, large vessel occlusion, and cardioembolism. Multivariable logistic regression analyses revealed that the independent factors associated with PVS were anterior circulation infarct (odds ratio [OR] 13.7; 95% confidence interval [CI] 3.5-53.3), large vessel occlusion (OR 123.3; 95% CI 33.7-451.5), and cardioembolism (OR 5.6; 95% CI 2.1-15.3). Anterior circulation infarct, large vessel occlusion, and cardioembolism are independently associated with the presence of PVS on SWI.

Value of MR imaging in the differentiation of benign and malignant orbital tumors in adults.

PURPOSE: To prospectively evaluate magnetic resonance (MR) imaging including dynamic contrast-enhanced MR imaging in the differentiation of benign from malignant orbital masses and to evaluate which MR imaging features are most predictive of malignant tumors. MATERIALS AND METHODS: The study was approved by the institutional review board and signed informed consent was obtained. Nonenhanced, static, and dynamic contrast-enhanced MR imaging was performed in 102 adult patients with an orbital mass. Diagnosis was based on histologic findings. MR imaging features of benign and malignant orbital lesions were evaluated correlated with histological findings. Multivariate logistic regression analysis was employed to identify the best combination of MR imaging features that might be predictive of malignancy. RESULTS: Nonenhanced, static, and dynamic enhancement MR imaging was significantly superior to two other models in prediction of malignancy (p < 0.05). Multivariate logistic regression analysis identified that the most discriminating MR imaging features were isointense mass on T2-weighted imaging and a washout-type time-intensity curve for both observers. CONCLUSION: Nonenhanced, static, and dynamic enhancement MR imaging improved differentiation between benign and malignant orbital masses in adult patients.

Melanin-Like Nanomaterials for Advanced Biomedical Applications: A Versatile Platform with Extraordinary Promise.

Developing efficient, sustainable, and biocompatible high-tech nanoplatforms derived from naturally existing components in living organisms is highly beneficial for diverse advanced biomedical applications. Melanins are nontoxic natural biopolymers owning widespread distribution in various biosystems, possessing fascinating physicochemical properties and playing significant physiological roles. The multifunctionality together with intrinsic biocompatibility renders bioinspired melanin-like nanomaterials considerably promising as a versatile and powerful nanoplatform with broad bioapplication prospects. This panoramic Review starts with an overview of the fundamental physicochemical properties, preparation methods, and polymerization mechanisms of melanins. A systematical and well-bedded description of recent advancements of melanin-like nanomaterials regarding diverse biomedical applications is then given, mainly focusing on biological imaging, photothermal therapy, drug delivery for tumor treatment, and other emerging biomedicine-related implementations. Finally, current challenges toward clinical translation with an emphasis on innovative design strategies and future striving directions are rationally discussed. This comprehensive and detailed Review provides a deep understanding of the current research status of melanin-like nanomaterials and is expected to motivate further optimization of the design of novel tailorable and marketable multifunctional nanoplatforms in biomedicine.

[Magnetic resonance imaging of the ocular motor nerves in normal volunteers].

OBJECTIVE: To display the detail functional anatomy of ocular motor nerves in the orbits, cavernous sinus and brainstem by high-resolution MRI. METHODS: Twenty normal subjects between 24 and 38 years of age, mean age was 28.25 +/- 4.07 (SD). Imaging of the ocular motor nerves at the brainstem was performed in 0.8 mm thickness image planes using 3D-FIESTA sequence; nerves in the cavernous sinus was imaged with a head coil, the FSE/T(1)WI was obtained in coronal planes; nerves to extraocular muscles (EOMs) in the orbits were imaged with FSE/T(1)WI oblique-coronal planes using surface coils, and within 2.0 mm thick planes. A human orbit was celloidin embedding and serially sectioned at 0.1 mm of thickness for HE stain, which would be used to distinguish motor nerves to the EOMs. RESULTS: Oculomotor nerves (CN3) and abducens (CN6) of the cisternal segment were well demonstrable in all normal subjects. Trochlear nerves (CN4) were depicted 95%. CN3 could be demonstrated consistently in the cavernous sinus, because of their small diameter, CN4 and CN6 not always detectable. The larger inferior division of CN3 and branches to the target EOMs and CN6 were demonstrated well in all species. The superior division of CN3 was demonstrated 60%, CN4 was showed 40%. CONCLUSION: 3D-FIESTA Sequence combined with MPR (Multiplanar Reformation) could precisely show the ocular motor nerves, as well as the relationships with adjacent structures in the cistern. The inferior division of CN3 and the CN6 could be well depicted in the orbits. But of the small sizes and complicated neighboring structures in the orbit, the superior division of the CN3 and the CN4 could not be demonstrated consistently. The capabilities of MRI can be fully used only with thorough knowledge of the complicated topographic relationships in the corresponding region.

Measurement and scan reproducibility of parameters of intravoxel incoherent motion in renal tumor and normal renal parenchyma: a preliminary research at 3.0 T MR.

PURPOSE: To prospectively estimate measurement and scan reproducibility of parameters of intravoxel incoherent motion (IVIM) in renal tumors, normal renal cortex, and medulla. METHODS: Twenty-four consecutive patients (twelve males and twelve females; median age 56.7 years, range 32-71 years) with 25 renal tumors (20 renal cell carcinomas, one urothelium carcinoma, three angiomyolipomas, and one oncocytoma) were examined twice using IVIM1 and IVIM2 with 9 and 16 b values, respectively, at 3.0 T. All the patients were re-scanned in 24-48 h. Regions of interest (ROIs) were placed in solid part of tumor, normal cortex, and medulla to derive IVIM parameters D (true diffusion coefficient), D* (pseudodiffusion coefficient), and f (perfusion fraction of pseudodiffusion). Differences in parameters between two IVIM sets and intra-observer, inter-observer, and scan-rescan differences were assessed using paired t tests. Intra-observer, inter-observer, and scan-rescan reproducibility were assessed by measuring coefficient of variation and Bland-Altman limits of agreements. RESULTS: Intra-observer reproducibility of renal tumors, normal renal cortex, and medulla was excellent for apparent diffusion coefficient (ADC; CV: 3.45%-5.34%, BA-LA: -14% to 18%) and D (CV: 3.65% to 6.04%, BA-LA: -18% to 19%), good for f (CV: 11.96%-16.08%, BA-LA: -76.4% to 92.1% except f of medulla with CV of 32.59% and BA-LA of -76.4% to 92.1% in IVIM1), and poor for D* (CV: 25.0% to 75.4%, BA-LA: -111% to 150%). The same order was in inter-observer reproducibility analysis. Scan-rescan reproducibility was the worst of the three parameters. Renal medulla showed worse reproducibility than renal tumors and the normal cortex. The metrics of IVIM2 had better reproducibility than IVIM1. CONCLUSION: Excellent reproducibility evaluation for ADC and D, good for f, and poor for D* derived from IVIM was performed in renal tumors, normal renal cortex, and medulla. D* has limited reliability and scan-rescan reproducibility should be improved.

Brain Abnormalities in Congenital Fibrosis of the Extraocular Muscles Type 1: A Multimodal MRI Imaging Study.

PURPOSE: To explore the possible brain structural and functional alterations in congenital fibrosis of extraocular muscles type 1 (CFEOM1) patients using multimodal MRI imaging. METHODS: T1-weighted, diffusion tensor images and functional MRI data were obtained from 9 KIF21A positive patients and 19 age- and gender-matched healthy controls. Voxel based morphometry and tract based spatial statistics were applied to the T1-weighted and diffusion tensor images, respectively. Amplitude of low frequency fluctuations and regional homogeneity were used to process the functional MRI data. We then compared these multimodal characteristics between CFEOM1 patients and healthy controls. RESULTS: Compared with healthy controls, CFEOM1 patients demonstrated increased grey matter volume in bilateral frontal orbital cortex and in the right temporal pole. No diffusion indices changes were detected, indicating unaffected white matter microstructure. In addition, from resting state functional MRI data, trend of amplitude of low-frequency fluctuations increases were noted in the right inferior parietal lobe and in the right frontal cortex, and a trend of ReHo increase (p<0.001 uncorrected) in the left precentral gyrus, left orbital frontal cortex, temporal pole and cingulate gyrus. CONCLUSIONS: CFEOM1 patients had structural and functional changes in grey matter, but the white matter was unaffected. These alterations in the brain may be due to the abnormality of extraocular muscles and their innervating nerves. Future studies should consider the possible correlations between brain morphological/functional findings and clinical data, especially pertaining to eye movements, to obtain more precise answers about the role of brain area changes and their functional consequence in CFEOM1.

CT and MR imaging findings of sinonasal angiomatous polyps.

OBJECTIVE: To characterize the CT and MR imaging findings of patients with sinonasal angiomatous polyps (SAPs) and evaluate their respective clinical value in the diagnosis of SAP. METHODS: CT and MR imaging findings of 15 patients with pathologically proven SAP were examined. Assessed image features included location, size, margin, attenuation, and change of the bony walls of the sinonasal cavity on CT, and signal intensity and enhancement pattern on MR. RESULTS: On CT, the SAP was mostly isoattenuated with patches of slight hyperattenuation. Most lesions caused changes in the adjacent bone, including expansile remodeling (n=8), defect or destruction (n=7), and hyperostosis (n=6). All lesions examined by MR showed heterogeneous isointense signal intensity on T1-weighted images and mixed obvious hyperintense and hypointense signal intensity with linear hypointense septum internally (n=10), and hypointense peripheral rim on T2-weighted images (n=10). Postcontrast MR images demonstrated areas of heterogeneous and marked enhancement with an unenhanced hypointense rim and septa (n=7). CONCLUSIONS: CT and MR imaging have respective advantages in the diagnosis of SAP. Combined application of CT and MR examinations is necessary for patients with suspected SAP.