Specificity Of Magnetic Resonance Imaging Research Articles

Accuracy of Multiplanar MR Images in Determination of Actual Tumour Size in Comparison to the Pelvic Examination of Carcinoma Cervix

Accurate staging of patients with cervical carcinoma is crucial for appropriate management planning and tumor size has consistently been a key component & major determinant when deciding management plan in especially with early-stages as it dictates whether a patient is a candidate for conservative surgery, radical hysterectomy or chemoradiation. Tumor size also provides a prognostic value, as larger tumors predict risk for distant spread of disease and poor prognostic outcomes. The objective of this study was to determine the sensitivity and specificity of Magnetic Resonance Imaging in the measurement of actual tumor size of invasive cervical carcinoma in comparison to pelvic examination taking histopathology as gold standard. This prospective cross sectional study was conducted in the Department of Radiology and Imaging, BSMMU, Dhaka during the period of September 2018 to August 2020. A total of 60 patients were selected purposively and all were undergone pelvic examination clinically by EUA. Then all of them underwent MRI in Department of Radiology and Imaging, BSMMU. Images of uterine cervix, corpus, vagina and parametrium are taken with a prefixed standard protocol and reporting was done by Radiologist. Comparison was done between the MRI and clinical assessment of actual tumour size. Out of 60 patients in this study the mean age was found 47.5±10.1 years with range from 22 to 60 years. Positive correlation (r=0.993; p=0.001) between histopathological size and MRI size of tumour. Positive correlation (r=0.950; p=0.001) between histopathological size and FIGO size of tumour. MRI findings more correlates with histopathology than clinically detected tumor size. Based on pathologic findings, accuracy was estimated by the degree of agreement with a difference of <0.5 or 1.0 cm between the measurements of tumor size obtained by pelvic examination and imaging modality. Pelvic examination and imaging modality had an accuracy of 53.3% and 75%, respectively, with a difference of <0.5 cm, and an accuracy of 88.3% and 100%, respectively, with a difference of 0.5-1.0 cm. The study also concluded MRI staging was more concordant with pathological stage compared to the clinical stage. Concordance rate of 95.0% in MRI and 65.0% in clinical staging respectively. FIGO staging concurred with histopathology in 39 (65.0%) cases and differed in 21 (35.0%) cases. Magnetic resonance imaging (MRI) is a sensitive and specific modality for accurate determination of tumour size as well as staging of cervical carcinoma in comparison to pelvic examination taking histopathology as gold standard.

Diffusion Weighted Magnetic Resonance Imaging in Differentiation of Benign and Malignant Thyroid Nodules

Abstract Background: Thyroid nodules are common; their clinical significance is mainly related to excluding malignancy. Re-gardless of the careful reporting of FNAC and frozen section biopsies, there is significant number of discordance with final histopathology reports, which leads to unnecessary thyroid-ectomies. DWI-MRI can help in the differentiation of benign and malignant thyroid nodules providing qualitative and quantitative information about the diffusion properties. Aim of Study: Is to determine the diagnostic accuracy of Diffusion-Weighted Imaging (DWI) and Apparent Diffusion Coefficient (ADC) mapping in differentiating benign from malignant thyroid nodules by taking histopathology as the gold standard. Patients and Methods: This study was performed on 32 cases who were diagnosed by ultrasonography to have thyroid nodules; in the General Naval Military Hospital. The patients were referred from the Surgery Department to the Radiology Department over a period of 18 months (January 2018-June 2018). Results: In this study the sensitivity of DWI and ADC mapping in differentiating benign from malignant thyroid nodules reached 100%. Conclusion: Quantitative DWI has a high sensitivity, and may be a reliable, non-invasive and non-radiative imaging modality for the detection of thyroid nodules. ADC values seem to be able to differentiate benign from malignant thyroid disease.

Actionable and incidental neuroradiological findings in twins with neurodevelopmental disorders

While previous research has investigated neuroradiological findings in autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD), the entire range of neurodevelopmental disorders (NDDs) has not yet been well-studied using magnetic resonance imaging (MRI). Considering the overlap among NDDs and simultaneous development of the brain and face, guided by molecular signaling, we examined the relationship of actionable and incidental (non-actionable) MRI findings and NDD diagnoses together with facial morphological variants and genetic copy number variants (CNVs). A cross-sectional study was conducted with a twin cohort 8–36 years of age (57% monozygotic, 40% dizygotic), including 372 subjects (46% with NDDs; 47% female) imaged by MRI, 280 with data for facial morphological variants, and 183 for CNVs. Fifty-one percent of participants had MRI findings. Males had a statistically significantly higher percentage of MRI findings (57.7%) compared with females (43.8%, p = 0.03). Twin zygosity was not statistically significantly correlated with incidence or severity of specific MRI findings. No statistically significant association was found between MRI findings and any NDD diagnosis or facial morphological variants; however, MRI findings were statistically significantly associated with the number of CNVs (OR 1.20, 95% CI 1.00–1.44, p = 0.05, adjusted OR for sex 1.24, 95% CI 1.03–1.50, p = 0.02). When combining the presence of MRI findings, facial morphological variants, and CNVs, statistically significant relationships were found with ASD and ADHD diagnoses (p = 0.0006 and p = 0.002, respectively). The results of this study demonstrate that the ability to identify NDDs from combined radiology, morphology, and CNV assessments may be possible. Additionally, twins do not appear to be at increased risk for neuroradiological variants.

Maltodextrin-Conjugated Gd-Based MRI Contrast Agents for Specific Diagnosis of Bacterial Infections.

Bacterial infections are one of the most serious health risks worldwide, and their rapid diagnosis remains a major challenge in clinic. To enhance the relaxivity and bacterial specificity of magnetic resonance imaging (MRI) contrast agents, here, a kind of gadolinium-based nanoparticles (NPs) of impressive biocompatibility is constructed as a contrast agent for maltodextrin-mediated bacteria-targeted diagnosis. To realize this, positively charged ultrasmall gadolinium oxide (Gd2O3, 2-3 nm) NPs are embedded in mesoporous silica NPs (MSN) with pore size around 6.38 nm. The resulting Gd2O3@MSN exhibits enhanced r1 value and T1-weighted MRI performance. Interestingly, upon conjugation of Gd2O3@MSN with maltodextrin to produce Gd2O3@MSN-Malt NPs, a remarkable decrease in internalization by osteosarcoma cells, alongside an increased adsorption toward E. coli and S. aureus, is achieved. It is therefore conceivable that the bacteria-targeted Gd2O3@MSN-Malt might be a promising MRI contrast agent for effective discrimination of bacterial infections from tumor.

An integrative multivariate approach for predicting functional recovery using magnetic resonance imaging parameters in a translational pig ischemic stroke model.

Magnetic resonance imaging (MRI) is a clinically relevant, real-time imaging modality that is frequently utilized to assess stroke type and severity. However, specific MRI biomarkers that can be used to predict long-term functional recovery are still a critical need. Consequently, the present study sought to examine the prognostic value of commonly utilized MRI parameters to predict functional outcomes in a porcine model of ischemic stroke. Stroke was induced via permanent middle cerebral artery occlusion. At 24 hours post-stroke, MRI analysis revealed focal ischemic lesions, decreased diffusivity, hemispheric swelling, and white matter degradation. Functional deficits including behavioral abnormalities in open field and novel object exploration as well as spatiotemporal gait impairments were observed at 4 weeks post-stroke. Gaussian graphical models identified specific MRI outputs and functional recovery variables, including white matter integrity and gait performance, that exhibited strong conditional dependencies. Canonical correlation analysis revealed a prognostic relationship between lesion volume and white matter integrity and novel object exploration and gait performance. Consequently, these analyses may also have the potential of predicting patient recovery at chronic time points as pigs and humans share many anatomical similarities (e.g., white matter composition) that have proven to be critical in ischemic stroke pathophysiology. The study was approved by the University of Georgia (UGA) Institutional Animal Care and Use Committee (IACUC; Protocol Number: A2014-07-021-Y3-A11 and 2018-01-029-Y1-A5) on November 22, 2017.

Multi‐institutional Evaluation of Radiologic Findings Associated With Pediatric Congenital Idiopathic Bilateral Vocal Fold Dysfunction

To report brain magnetic resonance imaging (MRI) and ultrasonography findings in pediatric patients with congenital idiopathic bilateral vocal fold dysfunction and analyze factors associated with its etiology and resolution. Case series with retrospective review. Tertiary care multi-institutional setting: Nationwide Children's Hospital, Indiana University, University of North Carolina, and Cleveland Clinic. Pediatric patients with congenital idiopathic bilateral vocal fold dysfunction were included in this review. Congenital idiopathic bilateral vocal fold dysfunction was identified in 74 patients from 2000 to 2018. Brain MRI scans were performed in all patients and ultrasonography in 30 (40.5%). Normal imaging results were most commonly found in patients born full-term (P < .0001) or via vaginal delivery (P < .01). Abnormal brain MRI and ultrasound results were found in 38 of 74 (51.3%) and 16 of 30 (53.3%), respectively. Type I Chiari malformation was not identified in any patient. No specific brain MRI or ultrasound abnormality was associated with patients' bilateral vocal fold dysfunction. Complete/incomplete bilateral vocal fold resolution occurred in 45 of 74 (60.8%) patients over the study interval and was not associated with brain MRI or ultrasound findings or birth complications but was associated with vaginal delivery (P = .02). Resolution rates were highest for patients with bilateral vocal fold paramedian paralysis (P = .05). In this multi-institutional study, no specific brain MRI or ultrasound abnormality was associated with patients' bilateral vocal fold dysfunction or subsequent resolution rates. While imaging is often performed to detect and treat any reversible causes of bilateral vocal fold dysfunction, in this series, imaging findings were heterogeneous and did not identify any treatable causes, such as type I Chiari malformation.

Role of Diffusion-Weighted and Chemical Shift Magnetic Resonance Imaging in Differentiation of Benign and Malignant Spinal Fractures

Atraumatic spinal compression fractures are common clinical problem. Differentiating benign osteoporotic fractures from pathological fractures due to malignant/metastatic lesions affects the management and prognoses in patients with known extraspinal malignancy. The objective of the research was to assess the role of conventional magnetic resonance imaging sequences with diffusion-weighted imaging and chemical-shift imaging in differentiating benign and malignant acute spinal compression fractures.&#x0D; Materials and Methods. The study included 40 patients with acute spinal compression fractures. Patients were evaluated using magnetic resonance imaging with diffusion-weighted imaging and chemical-shift imaging to differentiate benign etiology from malignant one. The results obtained were compared with histopathological follow-up for 6 months for definite clinical diagnoses.&#x0D; Results. No significant difference was noted in signal characteristics of benign and malignant fractures on T1, T2 and short-tau inversion recovery. However, posterior element involvement, soft tissue component and post-contrast enhancement were seen more frequently in malignant fractures (p&lt;0.05). On diffusion-weighted images, 77.8% of malignant fractures were hyperintense and 59.1% of benign fractures were hypointense (p&lt;0.05). The mean apparent diffusion coefficient value was 0.81 ± 0.19 for malignant and 1.24 ± 0.24 for benign fractures (p&lt;0.5). The mean signal intensity ratio for malignant fractures was 0.91 ± 0.125, whereas the signal intensity ratio for benign fractures was 0.64 ± 0.096 (p&lt;0.001).&#x0D; Conclusions. Signal characteristics on T1, T2 and short-tau inversion recovery sequences do not differentiate benign from malignant fractures; however, posterior element involvement, soft tissue and post contrast enhancement help in differentiating the etiology. Diffusion-weighted imaging and apparent diffusion coefficient values, as well as using chemical shift imaging further improve the diagnostic accuracy of magnetic resonance imaging.

Magnetic resonance imaging abnormalities as a marker of multiple system atrophy in isolated rapid eye movement sleep behavior disorder.

Patients with isolated rapid eye movement (REM) sleep behavior disorder (IRBD) develop Parkinson disease (PD), dementia with Lewy bodies (DLB), or multiple system atrophy (MSA). Magnetic resonance imaging (MRI) is abnormal in MSA showing abnormalities in the putamen, cerebellum, and brainstem. Our objective was to evaluate the usefulness of MRI to detect MRI abnormalities in IRBD and predict development of MSA and not PD and DLB. In IRBD patients that eventually developed PD, DLB, and MSA, we looked for the specific structural MRI abnormalities described in manifest MSA (e.g. hot cross-bun sign, putaminal rim, and cerebellar atrophy). We compared the frequency of these MRI changes among groups of converters (PD, DLB, and MSA) and analyzed their ability to predict development of MSA. The clinical and radiological features of the IRBD patients that eventually converted to MSA are described in detail. A total of 61 IRBD patients who underwent MRI phenoconverted to PD (n = 30), DLB (n = 26), and MSA (n = 5) after a median follow-up of 2.4 years from neuroimaging. MRI changes typical of MSA were found in four of the five (80%) patients who converted to MSA and in three of the 56 (5.4%) patients who developed PD or DLB. MRI changes of MSA had sensitivity of 80.0%, specificity of 94.6%, positive likelihood ratio of 14.9 (95% CI 4.6-48.8), and negative likelihood ratio of 0.2 (95% CI 0.04-1.2) to predict MSA. In IRBD, conventional brain MRI is helpful to predict conversion to MSA. The specific MRI abnormalities of manifest MSA may be detected in its premotor stage.

MRI Features as Prognostic Factors in Myxofibrosarcoma: Proposal of MRI Grading System

Myxofibrosarcoma (MFS) is a common soft tissue sarcoma in the elderly patients with both clinical and magnetic resonance imaging (MRI) peculiar features: very high recurrence rate, relatively low risk of distant metastases. On MRI it shows an infiltrative pattern ("tail sign") and high myxoid matrix content with water-like appearance on fluid-sensitive sequences. Due to these unusual characteristics, we propose a specific MRI grading system to stratify the risk of local recurrence (LR) and offer other prognostic information. Two expert radiologists retrospectively and blindly reviewed preoperative MRI of 150 patients affected by MFS of the extremities treated at a single Institution. Myxoid matrix component and contrast enhancement of the tumor were evaluated and graded with a semiquantitative method. The presence of an infiltrative pattern, the depth of the tumor (deep and/or superficial) and tumor sizes were also recorded. MRI features were analyzed separately and correlated to LR risk, sarcoma specific survival and distant metastases rate. Then, according to the statistical significance of the correlation between MRI features and prognosis a 3-grade scoring system was proposed and evaluated to assess the risk of LR. Mean age was 66.1 ± 14.4 years; mean follow-up was 16 ± 28.3 months. The MRI features most associated with higher risk of LR resulted to be: lesion sizes (both volume and maximum diameter with a cut-off of 20 cm - p = 0.01), the "tail sign" (p = 0.045), and high myxoid matrix content with MRI water-like appearance (p = 0.0493). Ninety-four patients (94 of 150- 62.7%) were grade 1, 33 (22.0%) grade 2, and 23 (15.3%) grade 3. Interobserver agreement was substantial with K= 0.779 (95%CI 0.685-0.874). Higher grades of MRI grading system proposed were significantly associated with an increased LR risk, hazard ratio = 2.031 (95%CI 1.366-3.019; p < 0.001). This is the largest series evaluating MRI features as prognostic factors for MFS. The MRI grading system proposed is significantly able to stratify the risk of LR in MFS of the extremities. The system is applicable to all the standard MRI studies protocols, might help in surgical planning, and may offer prognostic information.

Brain MRI Pattern Recognition in Neurodegeneration With Brain Iron Accumulation

Most neurodegeneration with brain iron accumulation (NBIA) disorders can be distinguished by identifying characteristic changes on magnetic resonance imaging (MRI) in combination with clinical findings. However, a significant number of patients with an NBIA disorder confirmed by genetic testing have MRI features that are atypical for their specific disease. The appearance of specific MRI patterns depends on the stage of the disease and the patient's age at evaluation. MRI interpretation can be challenging because of heterogeneously acquired MRI datasets, individual interpreter bias, and lack of quantitative data. Therefore, optimal acquisition and interpretation of MRI data are needed to better define MRI phenotypes in NBIA disorders. The stepwise approach outlined here may help to identify NBIA disorders and delineate the natural course of MRI-identified changes.

Tumor microenvironment responsive hollow mesoporous Co9S8@MnO2-ICG/DOX intelligent nanoplatform for synergistically enhanced tumor multimodal therapy

The development of multifunctional nanoplatform with combination of tumor microenvironment (TME)-responsive dual T1/T2 magnetic resonance (MR) imaging and synergistically self-enhanced photothermal/photodynamic/chemo-therapy is of significant importance for tumor theranostic, which still remains a great challenge. Herein, a novel hollow mesoporous double-shell Co9S8@MnO2 nanoplatform loaded with photodynamic agent of indocyanine green molecules (ICG) and chemotherapy drug of doxorubicin (DOX) was designed for TME responsive dual T1/T2 enhanced MR imaging and synergistically enhanced anti-tumor therapy. The designed nanoplatform with MnO2 shell can act as a TME-responsive oxygen self-supplied producer to alleviate tumor hypoxia and simultaneously improve photodynamic therapy (PDT) efficiency. Moreover, the TME-induced MnO2 dissolving and near-infrared (NIR) triggered photothermal nature from Co9S8 shell can further promote the tumor-targeted DOX release, leading to the synergistically improved anti-tumor efficacy. And the simultaneous enhancement in dual T1/T2 MR signal was achieved for highly specific tumor diagnosis. The in vivo and in vitro results confirmed that the designed TME-triggered nanoplatform with synergistic combination therapy presented good biocompatibility, and superior inhibition of tumor growth than monotherapy. This study provides the opportunities of designing intelligent TME-activated nanoplatform for highly specific tumor MR imaging and collaborative self-enhanced tumor therapy.

AUTOMATED CLASSIFICATION FOR BRAIN MRIS BASED ON 2D MF-DFA METHOD

Magnetic resonance image (MRI) is an important tool to diagnose human diseases effectively. It is very important for research and clinical application to classify the normal and abnormal human brain MRI images automatically. In this paper, an accurate and efficient technique is proposed to extract features of MRIs and classify these images into normal and abnormal categories. We use two-dimensional multifractal detrended fluctuation analysis (2D MF-DFA) to obtain image features. These features are the local generalized Hurst exponents calculated by 2D MF-DFA. In this regard, the values of Hurst exponents are given as the training input vector and are taken to the classifiers. We use [Formula: see text]-nearest neighbor ([Formula: see text]-NN) and support vector machine (SVM) to classify a specific brain MRI as normal or glioma affected. For SVM, we apply the leave-one-out cross-validation method for experimental verification. The 2D MF-DFA-SVM system achieved accuracy, sensitivity, and specificity of [Formula: see text] ±[Formula: see text], [Formula: see text], and [Formula: see text] ±[Formula: see text], respectively. The 2D MF-DFA-[Formula: see text]-NN system achieved accuracy, sensitivity, and specificity of [Formula: see text], [Formula: see text], and [Formula: see text], respectively. We find that when performing binary classification for brain MRIs, the SVM is superior to [Formula: see text]-NN. In addition, our experimental results indicate that the proposed 2D MF-DFA-SVM achieved excellent outcomes compared to those of the previous works. The proposed system is a promising system to clinical use.

Cost-effectiveness of Breast Cancer Screening With Magnetic Resonance Imaging for Women at Familial Risk

For women with a 20% or more familial risk of breast cancer without a known BRCA1/2 (BRCA1, OMIM 113705; and BRCA2, OMIM 114480) or TP53 (OMIM 151623) variant, screening guidelines vary substantially, and cost-effectiveness analyses are scarce. To assess the cost-effectiveness of magnetic resonance imaging (MRI) screening strategies for women with a 20% or more familial risk for breast cancer without a known BRCA1/2 or TP53 variant. In this economic evaluation, conducted from February 1, 2019, to May 25, 2020, microsimulation modeling was used to estimate costs and effectiveness on a lifetime horizon from age 25 years until death of MRI screening among a cohort of 10 million Dutch women with a 20% or more familial risk for breast cancer without a known BRCA1/2 or TP53 variant. A Dutch screening setting was modeled. Most data were obtained from the randomized Familial MRI Screening (FaMRIsc) trial, which included Dutch women aged 30 to 55 years. A health care payer perspective was applied. Several screening protocols with varying ages and intervals including those of the randomized FaMRIsc trial, consisting of the mammography (Mx) protocol (annual mammography and clinical breast examination) and the MRI protocol (annual MRI and clinical breast examination plus biennial mammography). Costs, life-years, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) were calculated and discounted by 3%. A threshold of €22 000 (US $24 795.87) per QALY was applied. This economic evaluation modeling study estimated that, on a lifetime horizon per 1000 women with the Mx protocol of the FaMRIsc trial, 346 breast cancers would be detected, and 49 women were estimated to die from breast cancer, resulting in 22 885 QALYs and total costs of €7 084 767 (US $7 985 134.61). The MRI protocol resulted in 79 additional QALYs and additional €2 657 266 (US $2 994 964.65). Magnetic resonance imaging performed only every 18 months between the ages of 35 and 60 years followed by the national screening program was considered optimal, with an ICER of €21 380 (US $24 097.08) compared with the previous nondominated strategy in the ranking, when applying the National Institute for Health and Care Excellence threshold. Annual screening alternating MRI and mammography between the ages of 35 and 60 years, followed by the national screening program, gave similar outcomes. Higher thresholds would favor annual MRI screening. The ICER was most sensitive to the unit cost of MRI and the utility value for ductal carcinoma in situ and localized breast cancer. This study suggests that MRI screening every 18 months between the ages of 35 and 60 years for women with a family history of breast cancer is cost-effective within the National Institute for Health and Care Excellence threshold for all densities. Higher thresholds would favor annual MRI screening. These outcomes support a change of current screening guidelines for this specific risk group and support MRI screening.

Value of diffusion weighted and ADC value - magnetic resonance imaging in differentiation between benign and malignant solid parotid gland masses

Background: magnetic resonance imaging (MRI) is becoming an essential tool for assessment of parotid gland pathology. Diffusion weighted imaging (DWI) provides quantitative and qualitative information reflecting the changes in tissue cellularity and integrity of cell membranes. Objective: To evaluate the diagnostic accuracy of diffusion weighted -MRI in the differentiation between benign and malignant solid parotid gland masses using 1.5 Tesla MRI scanner and to obtain the best cutoff value of apparent diffusion coefficient (ADC) to differentiate between benign and malignant masses. Patients and methods: prospective cross-sectional analytic study was conducted in Al Imamein Al Kadhumein Medical City, at the period between January 2019 and January 2020, 50 patients were included in the study. DWI was acquired at following b-values [50, 1000 millimeter (mm) 2/second (sec)], in this study the results were obtained and depending on b-value 1000 mm2/sec. Results: The mean level of ADC value of malignant masses (0.599 ± 0.117 SD x 10-3 mm2/sec), while for benign masses (1.590 ± 0.363 SD x10-3 mm2/sec); According to Receiver operating characteristic (ROC) curve the optimal cutoff point of ADC value was (0.914x10-3 mm2/sec) with sensitivity 100%, specificity 97%. The association between MRI diagnosis and histopathological diagnosis was significant (P value< 0.001). Conclusion: Diffusion weighted- MRI and ADC values are highly sensitive and specific to differentiate between benign and malignant solid parotid gland masses and the best ADC cut off value was (0.914x10-3 mm2/sec).

Clinical features and MRI characteristics of presumptive constrictive myelopathy in 27 pugs.

Constrictive myelopathy has been described in pugs with paraparesis and is characterized by fibrous connective and granulation tissue within the dura mater causing spinal cord compression and focal gliosis. An association between constrictive myelopathy and caudal articular process (CAP) dysplasia is suspected; however, some studies have reported CAP dysplasia as an incidental finding. The imaging appearance of constrictive myelopathy is currently limited to a small number of cases. The aim of this multicenter, retrospective, descriptive study was to detail the magnetic resonance imaging (MRI) characteristics and to correlate these with clinical signs of presumptive constrictive myelopathy in pugs. Medical databases from five veterinary referral hospitals were reviewed to identify pugs with pelvic limb ataxia and paresis, that had a complete record of signalment, neurological examination, and MRI of the thoracolumbar spinal cord. The exclusion criteria were pugs with other conditions, such as unequivocal subarachnoid diverticula, hemivertebrae causing vertebral canal stenosis, intervertebral disc extrusions/protrusions, and multifocal/diffuse lesions. Twenty-seven pugs met the inclusion criteria. All cases were ambulatory with paraparesis and ataxia. Nearly 60% were incontinent. Magnetic resonance imaging revealed a focal myelopathy in all cases showing one or more of the following lesions: CAP dysplasia (25/27), focal subarachnoid space irregular margination (26/27) with circumferential or dorsal contrast enhancement (10/12), and a symmetric V-shaped ventral extradural lesion (23/27). This study describes specific MRI features of pugs with presumptive constrictive myelopathy, which authors hypothesize to be a consequence of chronic micro-motion. Our results may help in diagnosing and subsequently treating this condition, which may warrant vertebral stabilization.

MRI of intestinal endometriosis.

Endometriosis is a common gynecological condition of unknown etiology, which mainly affects women of reproductive age. The commonest site of gastrointestinal endometriosis is the rectosigmoid colon. Involvement of the sigmoid, cecum, appendix, and small bowel are less common, but one third of rectosigmoid endometriosis is associated with right-sided extra-pelvic bowel endometriosis. Intestinal endometriosis represents one of the most severe forms of deep endometriosis (DE). Magnetic resonance imaging (MRI) is recommended as a second-line technique in the preoperative workup of DE, especially for gastrointestinal endometriosis. An optimal MRI protocol is required for a complete mapping of endometriotic lesions. MRI could be used as a triage test in the diagnosis of rectosigmoid colon endometriosis. Magnetic resonance enterography should be additionally performed requiring a specific additional MRI protocol for the evaluation of multicentric intestinal endometriotic lesions. Except other imaging techniques, the aim of this chapter is to expose indications for MRI, technical requirements, patient preparation, MRI protocols, and criteria for the diagnosis of intestinal endometriosis.

MRI and Clinical Risk Indicators for Osteomyelitis.

Introduction. The sensitivity and specificity for magnetic resonance imaging (MRI) diagnosis of osteomyelitis is 90% and 80%, respectively; findings include bone marrow edema, T2-weighted image hyperintensity (HI-T2WI), T1-weighted image confluent signal(CS-T1WI), and cortical erosion (CE). The goal is to determine which risk factors and MRI findings are most predictive of osteomyelitis. Materials and Methods. After institutional review board approval, records of patients who underwent bone biopsy of the foot/ankle between 2015 and 2017 were reviewed. Diagnosis was determined histologically. Blinded MRI review identified indicators of osteomyelitis: HI-T2WI, CS-T1WI, ulcer depth, and CE. Bivariate and multivariate regression determined an association between osteomyelitis and radiographic indicators. Results. Of 59 subjects, 41 (69.5%) and 18 (30.5%) had pathologic evidence of osteomyelitis or were indeterminate. The sensitivity and specificity by radiologist diagnosis was 51.4% and 91.7%, respectively. Diabetes (relative risk [RR]=2.9, 95% CI = 1.0.8-7.77, P = .034), CS-T1WI (RR = 1.6, 95% CI = 1.23-2.20, P < .001), and CE (RR = 1.8, 95% CI = 1.34-2.28, P < .001) were risk factors on bivariate analysis. Ulcer depth demonstrated a trend toward statistical significance. Diabetes (RR = 2.4, 95% CI = 1.00-5.69, P = .049) and CE (RR = 1.7, 95% CI = 1.27-2.37, P < .001) were independent risk factors on multivariate analysis. Discussion. Diabetes and CS-T1WI are independent risk factors for pedal osteomyelitis. Patients with diabetes, CS-T1WI, and CE should be evaluated for osteomyelitis with recommendation for bone biopsy in appropriate clinical settings.Levels of Evidence: Level III Retrospective Comparative Study.

Modern methods of radiologic diagnosis of gastric cancer

The patients with gastric cancer (GC) sometimes have a very poor prognosis. In general, it depends on the time of GC verification, which dramatically changes prognosis and treatment plans. This article reflects current data on the epidemiology, mortality rate, and rates of the incidence of gastric cancer in different countries of the world. The most common and clinically convenient classifications and staging systems for gastric cancer are given, the need for the earliest possible diagnosis and verification of the stage of the tumor process is substantiated. There are considered in details the modern methods of the gastric cancer diagnostics, including esophagogastroduodenoscopy (EGD), as the method of choice for the primary detection of gastric cancer, and various methods of radiation imaging, including multispiral computed tomography and endoscopic ultrasonography (EUS), combined with chromoendoscopy, narrow-band tomography, and confocal laser endoscopy. Particular attention is paid to the presentation of various methods of preoperative T-staging and N-staging of gastric cancer, comparing the diagnostic accuracy of MSCT and endoscopic ultrasonography. Diagnostic accuracy, sensitivity, and specificity of magnetic resonance imaging (MRI) and positron emission tomography (PET) are presented. Special attention is paid to the comparative analysis of the effectiveness of various imaging techniques in assessing the effectiveness of neoadjuvant chemotherapy; the results of tumor volumetry are compared with the histological response according to the Mandard score. Further prospects for the application and development of radiological research techniques are discussed.

Assessment of Meniscal Healing Status by Magnetic Resonance Imaging T2 Mapping After Meniscal Repair

Background: Although the sensitivity and specificity of magnetic resonance imaging (MRI) for the diagnosis of primary meniscal tears are high, these values are lower for the assessment of healing status of repaired menisci. Purpose: To compare the accuracy of MRI T2 mapping and conventional MRI in assessing meniscal healing after repair. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Patients who underwent meniscal repair with concurrent anterior cruciate ligament reconstruction between 2012 and 2016 and had a follow-up second-look arthroscopy were enrolled. The patients were divided into healed and incompletely/not healed groups based on the second-look arthroscopy findings. For the repaired menisci, the following were compared between the groups, (1) Stoller and Crues classification on conventional MRI with a proton density-weighted fat-saturated sequence and (2) the remaining colored meniscal tear line on T2 mapping coincident with the high signal line showing the primary tear on conventional MRI were compared. The change of T2 relaxation time (ΔT2) of the colored meniscal tear line pre- to postoperatively was compared between the groups. The mean T2 relaxation time of the whole area of the postoperative meniscus at each slice was also compared with that of control menisci to assess the whole quality of the repaired meniscus. Results: A total of 26 menisci from 24 knees were assessed (16 healed menisci, 10 incompletely/not healed menisci). According to the Crues classification on conventional MRI, 8 of 16 healed menisci and 3 of 10 incompletely/not healed menisci improved from grade 3 to 2, with there being no significant difference between the groups (P = .43). However, the colored meniscal tear line remained in only 3 of the 16 healed menisci as compared with 9 of the 10 incompletely/not healed menisci, and the presence of this colored line allowed differentiation between healed menisci and incompletely/not healed menisci (sensitivity, 81.3%; specificity, 90.0%; odds ratio, 39.0; P = .001). The mean (SD) ΔT2 was −31.1 ± 3.2 and −19.9 ± 4.4 ms in the healed and incompletely/not healed groups, respectively (P < .001). Receiver operating characteristic curve analysis showed a cutoff ΔT2 value of −22.3 ms for separation of meniscal healing (P < .001). The T2 relaxation times of the whole area of the repaired menisci were 31.7 ± 3.4 and 32.8 ± 3.8 ms in the healed and incompletely/unhealed groups, respectively (P = .69), with these values being significantly longer than the 26.9 ± 2.2 ms in the controls (P < .001). Conclusion: MRI T2 mapping allowed the differentiation of healing status after meniscal repair, with high sensitivity and specificity as compared with conventional MRI.

The effect of ApoE ε 4 on clinical and structural MRI markers in prodromal Alzheimer's disease.

Apolipoprotein E (ApoE) ε 4 has been identified as the strongest genetic risk factor for Alzheimer's disease (AD). However, the importance of ApoE ε 4 on clinical and biological heterogeneity of AD is still to be determined, particularly at the prodromal stage. Here, we evaluate the association of ApoE ε 4 with clinical cognition and neuroimaging regions in mild cognitive impairment (MCI) participants based on the AT (N) system, which is increasingly essential for developing a precise assessment of AD. We stratified 178 A+T+MCI participants (prodromal AD) into ApoE ε 4 (+) and ApoE ε 4 (-) according to ApoE genotype from the Alzheimer's Disease Neuroimaging Initiative (ADNI). We determined Aβ-positivity (A+) by the standardized uptake values ratios (SUVR) means of florbetapir-PET-AV45 (the cut-off value of 1.1) and fibrillar tau-positivity (T+) by cerebrospinal fluid (CSF) phosphorylated-tau at threonine 181 position (p-Tau) (cut-off value of 23 pg/mL). We evaluated the effect of ApoE ε 4 status on cognitive conditions and brain atrophy from structural magnetic resonance imaging (MRI) scans. A multivariate analysis of variance was used to compare the differences of cognitive scores and brain atrophy from structural MRI regions of interest (ROIs) between both groups. Furthermore, we performed a linear regression model to assess the correlation between signature ROIs of structural MRI and cognitive scores in the prodromal AD participants. ApoE ε 4 (+) prodromal AD participants had lower levels of CSF Aβ 1-42, higher levels of t-Tau, more memory and global cognitive impairment, and faster decline of global cognition, compared to ApoE ε 4 (-) prodromal AD. ApoE ε 4 (+) prodromal AD participants had a thinner cortical thickness of bilateral entorhinal, smaller subcortical volume of the left amygdala, bilateral hippocampus, and left ventral diencephalon (DC) relative to ApoE ε 4 (-) prodromal AD. Furthermore, the cortical thickness average of bilateral entorhinal was highly correlated with memory and global cognition. ApoE ε 4 status in prodromal AD participants has an important effect on clinical cognitive domains. After ascertaining the ApoE ε 4 status, specific MRI regions can be correlated to the cognitive domain and will be helpful for precise assessment in prodromal AD.