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

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

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

This paper introduces the significance, the present development situation and some suggestions of the medical measurements.
Diagnostic Equipment ; standards ; Equipment and Supplies ; standards ; Magnetic Resonance Imaging ; instrumentation ; standards ; Medical Staff ; education ; Research Design ; standards ; Tomography, X-Ray Computed ; standards

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

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

Our purpose is to introduce and analyze the data quality assurance (DQA) protocol of functional magnetic resonance imaging (fMRI). A water phantom was scanned to get DQA indexes. An fMRI sequence was used to get signal noise ratio (SNR) and Drift, which was calculated from maximum difference ratio of the average signal intensity in the region of interest (ROI) of image serials. The long period application of this method demonstrated that this DQA protocol can reflect imaging performance and the state of stability of the MRI scanner. Some application experience and discussion involved in DQA were also presented here.
Algorithms ; Artifacts ; Artificial Intelligence ; Humans ; Image Processing, Computer-Assisted ; methods ; Magnetic Resonance Imaging ; methods ; Phantoms, Imaging ; standards ; Quality Control

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

The clinical staging system for cervical carcinoma presently recommended by the International Federation of Gynecology and Obstetrics (FIGO) does not include MRI or CT findings and thus suffers limited accuracy. Recently however, the positive contributions of MRI and CT to preoperative staging have been reported. This study involves a determination of the value of routine cystoscopy and intravenous urography, in the detection of bladder invasion or hydronephrosis resulting from cervical carcinoma, among patients who had undergone MRI or CT. Among a total 296 patients with cervical carcinoma, 271 patients (92%) had undergone MRI and 25 (8%) CT. Bladder invasion was identified pathologically by cystoscopic biopsy in 8 (57%) of the 14 patients with suspected bladder invasion on MRI or CT. There was no bladder invasion in any of the other cases lacking in bladder invasion evidence on MRI or CT. Hydronephrosis was identified by intravenous urography in 18 patients, as it also was in all of these cases on MRI or CT, confirming a negative predictive value for MRI or CT, in detecting bladder invasion or hydronephrosis from cervical carcinoma, of 100%. Therefore, although MRI or CT cannot totally replace cystoscopy, the latter is unnecessary in the absence of bladder invasion evidence on MRI or CT. Intravenous urography, however, can be safely omitted whenever MRI or CT is performed.
Adult ; Aged ; Aged, 80 and over ; Carcinoma/*diagnosis/pathology ; Cervix Neoplasms/*diagnosis/pathology ; Cystoscopy/*standards ; Female ; Human ; Magnetic Resonance Imaging/*standards ; Middle Age ; Neoplasm Staging ; *Tomography, X-Ray Computed/*standards ; Urography/*standards

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