In order to evaluate the quality of different brands of magnetic resonance imaging system, optimize the quality of equipment repair and maintenance, and ensure the quality and safety of the equipment in clinical use. Meanwhile build the reliability evaluation model of magnetic resonance imaging equipment based on the large failure data collected by magnetic resonance repair system. In this paper, using the fault data of a certain brand of magnetic resonance in the past two years, applying the statistical judgment criterion, selecting the appropriate statistical distribution model, and finally fitting the equipment reliability evaluation model based on the non-homogeneous Poisson process, and then obtaining the magnetic resonance imaging equipment. Reliability evaluation indicators such as cumulative fault strength function, magnetic resonance imaging equipment fault density function, and mean time between failures. According to the calculated reliability index, on the one hand, it can evaluate the system reliability quality of a certain brand of magnetic resonance imaging equipment, and then evaluate the quality of different brands of magnetic resonance imaging equipment, on the other hand, it can help hospital equipment managers to carry out operational optimization, maintenance strategy development and safety management of magnetic resonance imaging equipment.
Equipment and Supplies, Hospital/standards* ; Magnetic Resonance Imaging/instrumentation* ; Reproducibility of Results

The quality inspection of magnetic resonance imaging (MRI) performance parameters is an important means to ensure the image quality and the reliability of diagnosis results. There are some problems in the manual calculation and eye recognition of the quality inspection parameters, such as strong subjectivity and low efficiency. In view of these facts, an automatic analysis system for MRI quality detection based on QT is proposed and implemented in C++ language. The image processing algorithm is introduced to automatically measure and calculate the quality inspection parameters. The software with comprehensive functions is designed to systematically manage the quality inspection information of MRI. The experimental results show that the automatically calculated parameters are consistent with the manually calculated ones. Accordingly, the accuracy and reliability of the algorithm is verified. The whole system is efficient, convenient and easy to operate, and it can meet the actual needs of MRI quality inspection.
Algorithms ; Image Processing, Computer-Assisted ; Magnetic Resonance Imaging ; standards ; Reproducibility of Results

ISO 14708-3 "Implants for surgery-active implantable medical devices-Part 3:implantable neurostimulators" 2017 version and 2008 version are compared, and changes in the standard are interpreted combined with the characteristics of the neurostimulator. The new version of the standard for the first time in the introduction mentioned a new type of non-electrode or extension's neurostimulator. Key issues that have significant impact on safety concerns such as wireless charging temperature rise, MRI acceptance criteria, etc., are given for the first time in the new version. New requirements to the wireless communication section are added, and the electromagnetic compatibility part is greatly adjusted. With more miniature non-electrode or extension's neurostimulator entering the market, standards such as electromagnetic compatibility and MRI, there will be greater adjustments.
Electromagnetic Phenomena ; Implantable Neurostimulators ; standards ; Magnetic Resonance Imaging ; Prostheses and Implants ; Reference Standards

Animals ; Macaca mulatta ; surgery ; Magnetic Resonance Imaging ; Neuronavigation ; standards ; Stereotaxic Techniques ; standards

Whole body integrated magnetic resonance imaging (MR)/positron emission tomography (PET) imaging systems have recently become available for clinical use and are currently being used to explore whether the combined anatomic and functional capabilities of MR imaging and the metabolic information of PET provide new insight into disease phenotypes and biology, and provide a better assessment of oncologic diseases at a lower radiation dose than a CT. This review provides an overview of the technical background of combined MR/PET systems, a discussion of the potential advantages and technical challenges of hybrid MR/PET instrumentation, as well as collection of possible solutions. Various early clinical applications of integrated MR/PET are also addressed. Finally, the workflow issues of integrated MR/PET, including maximizing diagnostic information while minimizing acquisition time are discussed.
Coordination Complexes/chemistry/diagnostic use ; Heart/radiography ; Humans ; *Magnetic Resonance Imaging ; Neoplasm Metastasis ; Neoplasm Staging ; Neoplasms/pathology/radiography ; *Positron-Emission Tomography ; Radiopharmaceuticals/diagnostic use ; Tomography, X-Ray Computed ; Whole Body Imaging/*standards/*trends

The objective of this article is to research magnetic resonance compatibility for coronary mental stents, and to evaluate the magnetic resonance compatibility based on laboratory testing results. Coronary stents magnetic resonance compatibility test includes magnetically induced displacement force test, magnetically induced torque test, radio frequency induced heating and evaluation of MR image. By magnetic displacement force and torque values, temperature, and image distortion values to determine metal coronary stent demagnetization effect. The methods can be applied to test magnetic resonance compatibility for coronary mental stents and evaluate its demagnetization effect.
Equipment Design ; Magnetic Resonance Imaging ; Magnetics ; Metals ; Radio Waves ; Stents ; standards ; Temperature ; Torque

Perfusion is a fundamental biological function that refers to the delivery of oxygen and nutrients to tissue by means of blood flow. Perfusion MRI is sensitive to microvasculature and has been applied in a wide variety of clinical applications, including the classification of tumors, identification of stroke regions, and characterization of other diseases. Perfusion MRI techniques are classified with or without using an exogenous contrast agent. Bolus methods, with injections of a contrast agent, provide better sensitivity with higher spatial resolution, and are therefore more widely used in clinical applications. However, arterial spin-labeling methods provide a unique opportunity to measure cerebral blood flow without requiring an exogenous contrast agent and have better accuracy for quantification. Importantly, MRI-based perfusion measurements are minimally invasive overall, and do not use any radiation and radioisotopes. In this review, we describe the principles and techniques of perfusion MRI. This review summarizes comprehensive updated knowledge on the physical principles and techniques of perfusion MRI.
Arteries/chemistry ; Brain Neoplasms/radiography ; Contrast Media/diagnostic use ; Humans ; Magnetic Resonance Imaging/standards/*trends ; Spin Labels ; Stroke/radiography

OBJECTIVE: To investigate the interobserver reproducibility and diagnostic feasibility of a visual grading system for assessing atrophy of the supraspinatus muscle on magnetic resonance imaging (MRI). MATERIALS AND METHODS: Three independent radiologists retrospectively evaluated the occupying ratio of the supraspinatus muscle in the supraspinatus fossa on 192 shoulder MRI examinations in 188 patients using a 3-point visual grading system (1, > or = 60%; 2, 30-59%; 3, < 30%) on oblique sagittal T1-weighted images. The inter-reader agreement and the agreement with the reference standard (3-point grades according to absolute occupying ratio values quantitatively measured by directly contouring the muscles on MRI) were analyzed using weighted kappa. The visual grading was applied by a single reader to a group of 100 consecutive patients who had undergone rotator cuff repair to retrospectively determine the association between the visual grades at preoperative state and postsurgical occurrences of retear. RESULTS: The inter-reader weighted kappa value for the visual grading was 0.74 when averaged across three reader pairs (0.70-0.77 for individual reader pairs). The weighted kappa value between the visual grading and the reference standard ranged from 0.75 to 0.83. There was a significant difference in retear rates of the rotator cuff between the 3 visual grades of supraspinatus muscle atrophy on MRI in univariable analysis (p < 0.001), but not in multivariable analysis (p = 0.026). CONCLUSION: The 3-point visual grading system may be a feasible method to assess the severity of supraspinatus muscle atrophy on MRI and assist in the clinical management of patients with rotator cuff tear.
Adult ; Aged ; Feasibility Studies ; Female ; Humans ; Joint Diseases ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Muscular Atrophy/diagnosis/*pathology ; Observer Variation ; Reference Standards ; Reproducibility of Results ; Retrospective Studies ; Rotator Cuff/*pathology ; Young Adult

OBJECTIVE: The purpose of this study was to compare the image quality of standard single-shot echo-planar imaging (ss-EPI) and that of readout-segmented EPI (rs-EPI) in patients with breast cancer. MATERIALS AND METHODS: Seventy-one patients with 74 breast cancers underwent both ss-EPI and rs-EPI. For qualitative comparison of image quality, three readers independently assessed the two sets of diffusion-weighted (DW) images. To evaluate geometric distortion, a comparison was made between lesion lengths derived from contrast enhanced MR (CE-MR) images and those obtained from the corresponding DW images. For assessment of image parameters, signal-to-noise ratio (SNR), lesion contrast, and contrast-to-noise ratio (CNR) were calculated. RESULTS: The rs-EPI was superior to ss-EPI in most criteria regarding the qualitative image quality. Anatomical structure distinction, delineation of the lesion, ghosting artifact, and overall image quality were significantly better in rs-EPI. Regarding the geometric distortion, lesion length on ss-EPI was significantly different from that of CE-MR, whereas there were no significant differences between CE-MR and rs-EPI. The rs-EPI was superior to ss-EPI in SNR and CNR. CONCLUSION: Readout-segmented EPI is superior to ss-EPI in the aspect of image quality in DW MR imaging of the breast.
Adult ; Aged ; Aged, 80 and over ; Artifacts ; Breast/pathology ; Breast Neoplasms/pathology ; Contrast Media/diagnostic use ; Diffusion Magnetic Resonance Imaging/methods/*standards ; Echo-Planar Imaging/methods/*standards ; Female ; Humans ; Image Enhancement/methods/*standards ; Middle Aged ; Observer Variation ; Retrospective Studies ; Sensitivity and Specificity ; Signal-To-Noise Ratio

OBJECTIVE: To evaluate the accuracy of magnetic resonance imaging (MRI) with lumen distention for rectal cancer staging and circumferential resection margin (CRM) involvement prediction. MATERIALS AND METHODS: Seventy-three patients with primary rectal cancer underwent high-resolution MRI with a phased-array coil performed using 60-80 mL room air rectal distention, 1-3 weeks before surgery. MRI results were compared to postoperative histopathological findings. The overall MRI T staging accuracy was calculated. CRM involvement prediction and the N staging, the accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were assessed for each T stage. The agreement between MRI and histological results was assessed using weighted-kappa statistics. RESULTS: The overall MRI accuracy for T staging was 93.6% (k = 0.85). The accuracy, sensitivity, specificity, PPV and NPV for each T stage were as follows: 91.8%, 86.2%, 95.5%, 92.6% and 91.3% for the group < or = T2; 90.4%, 94.6%, 86.1%, 87.5% and 94% for T3; 98,6%, 85.7%, 100%, 100% and 98.5% for T4, respectively. The predictive CRM accuracy was 94.5% (k = 0.86); the sensitivity, specificity, PPV and NPV were 89.5%, 96.3%, 89.5%, and 96.3% respectively. The N staging accuracy was 68.49% (k = 0.4). CONCLUSION: MRI performed with rectal lumen distention has proved to be an effective technique both for rectal cancer staging and involved CRM predicting.
Adult ; Aged ; *Air ; Dilatation/methods ; Female ; Humans ; Magnetic Resonance Imaging/*methods/standards ; Male ; Middle Aged ; Neoplasm Staging/*methods ; Prospective Studies ; Rectal Neoplasms/*pathology/surgery ; Rectum/*pathology ; Sensitivity and Specificity