Reduced Imaging Time and Improved Image Quality of 3D Isotropic T2-Weighted Magnetic Resonance Imaging with Compressed Sensing for the Female Pelvis

This study is to compare three-dimensional(3D)isotropic T2-weighted magnetic resonance imaging(MRI)with compressed sensing-sampling perfection with application optimized contrast(CS-SPACE)and the conventional image(3D-SPACE)sequence in terms of image quality,estimated signal-to-noise ratio(SNR),relative contrast-to-noise ratio(CNR),and the lesions’conspicuous of the female pelvis.Thirty-six females(age:51,28-73)with cervical carcinoma(n=20),rectal carcinoma(n=7),or uterine fibroid(n=9)were included.Patients underwent magnetic resonance(MR)imaging at a 3T scanner with the sequences of 3D-SPACE,CS-SPACE,and twodimensional(2D)T2-weighted turbo-spin echo(TSE).Quantitative analyses of estimated SNR and relative CNR between tumors and other tissues,image quality,and tissue conspicuity were performed.Two radiologists assessed the difference in diagnostic findings for carcinoma.Quantitative values and qualitative scores were analyzed,respectively.The estimated SNR and the relative CNR of tumor-to-muscle obturator internus,tumor-to-myometrium,and myometrium-to-muscle obturator internus was comparable between 3D-SPACE and CS-SPACE.The overall image quality and the conspicuity of the lesion scores of the CS-SPACE were higher than that of the 3D-SPACE(P<0.01).The CS-SPACE sequence offers shorter scan time,fewer artifacts,and comparable SNR and CNR to conventional 3D-SPACE,and has the potential to improve the performance of T2-weighted images.

Cardiac functional magnetic resonance imaging at 7T:Image quality optimization and ultra-high field capabilities

BACKGROUND 7T cardiac magnetic resonance imaging(MRI)introduces several advantages,as well as some limitations,compared to lower-field imaging.The capabilities of ultra-high field(UHF)MRI have not been fully exploited in cardiac functional imaging.AIM To optimize 7T cardiac MRI functional imaging without the need for conducting B1 shimming or subject-specific tuning,which improves scan efficiency.In this study,we provide results from phantom and in vivo scans using a multi-channel transceiver modular coil.METHODS We investigated the effects of adding a dielectric pad at different locations next to the imaged region of interest on improving image quality in subjects with different body habitus.We also investigated the effects of adjusting the imaging flip angle in cine and tagging sequences on improving image quality,B1 field homogeneity,signal-to-noise ratio(SNR),blood-myocardium contrast-to-noise ratio(CNR),and tagging persistence throughout the cardiac cycle.RESULTS The results showed the capability of achieving improved image quality with high spatial resolution(0.75 mm×0.75 mm×2 mm),high temporal resolution(20 ms),and increased tagging persistence(for up to 1200 ms cardiac cycle duration)at 7T cardiac MRI after adjusting scan set-up and imaging parameters.Adjusting the imaging flip angle was essential for achieving optimal SNR and myocardium-toblood CNR.Placing a dielectric pad at the anterior left position of the chest resulted in improved B1 homogeneity compared to other positions,especially in subjects with small chest size.CONCLUSION Improved regional and global cardiac functional imaging can be achieved at 7T MRI through simple scan set-up adjustment and imaging parameter optimization,which would allow for more streamlined and efficient UHF cardiac MRI.

Role of pulmonary perfusion magnetic resonance imaging for the diagnosis of pulmonary hypertension:A review

Among five types of pulmonary hypertension,chronic thromboembolic pulmonary hypertension(CTEPH)is the only curable form,but prompt and accurate diagnosis can be challenging.Computed tomography and nuclear medicine-based techniques are standard imaging modalities to non-invasively diagnose CTEPH,however these are limited by radiation exposure,subjective qualitative bias,and lack of cardiac functional assessment.This review aims to assess the methodology,diagnostic accuracy of pulmonary perfusion imaging in the current literature and discuss its advantages,limitations and future research scope.

A modified method for locating parapharyngeal space neoplasms on magnetic resonance images: implications for differential diagnosis

The parapharyngeal space(PPS) is an inverted pyramid-shaped deep space in the head and neck region, and a variety of tumors, such as salivary gland tumors, neurogenic tumors, nasopharyngeal carcinomas with parapharyngeal invasion, and lymphomas, can be found in this space. The differential diagnosis of PPS tumors remains challenging for radiologists. This study aimed to develop and test a modified method for locating PPS tumors on magnetic resonance(MR) images to improve preoperative differential diagnosis. The new protocol divided the PPS into three compartments: a prestyloid compartment, the carotid sheath, and the areas outside the carotid sheath. PPS tumors were located in these compartments according to the displacements of the tensor veli palatini muscle and the styloid process, with or without blood vessel separations and medial pterygoid invasion. This protocol, as well as a more conventional protocol that is based on displacements of the internal carotid artery(ICA), was used to assess MR images captured from a series of 58 PPS tumors. The consequent distributions of PPS tumor locations determined by both methods were compared. Of all 58 tumors, our new method determined that 57 could be assigned to precise PPS compartments. Nearly all(13/14; 93%) tumors that were located in the pre-styloid compartment were salivary gland tumors. All 15 tumors within the carotid sheath were neurogenic tumors. The vast majority(18/20; 90%) of trans-spatial lesions were malignancies. However, according to the ICA-based method, 28 tumors were located in the pre-styloid compartment, and 24 were located in the post-styloid compartment, leaving 6 tumors that were difficult to locate. Lesions located in both the pre-styloid and the post-styloid compartments comprised various types of tumors. Compared with the conventional ICA-based method, our new method can help radiologists to narrow the differential diagnosis of PPS tumors to specific compartments.

Optimized cardiac magnetic resonance imaging inversion recovery sequence for metal artifact reduction and accurate myocardial scar assessment in patients with cardiac implantable electronic devices

Late gadolinium enhancement(LGE) cardiovascular magnetic resonance(CMR) is the gold standard for imaging myocardial viability.An important application of LGE CMR is the assessment of the location and extent of the myocardial scar in patients with ventricular tachycardia(VT), which allows for more accurate identification of the ablation targets.However, a large percentage of patients with VT have cardiac implantable electronic devices(CIEDs), which is a relative contraindication for cardiac magnetic resonance imaging due to safety and image artifact concerns.Previous studies showed that these patients can be safely scanned on 1.5 T scanners provided that an adequate imaging protocol is adopted.Nevertheless, imaging patients with a CIED result in metal artifacts due to the strong frequency off-resonance effects near the device; therefore, the spins in the surrounding myocardium are not completely inverted, and thus give rise to hyperintensity artifacts.These artifacts obscure the myocardial scar tissue and limit the ability to study the correlation between the myocardial scar structure and the electro-anatomical map during catheter ablation.In this study, we developed a modified inversion recovery technique to alleviate the CIED-induced metal artifacts and improve the diagnostic image quality of LGE images in patients with CIEDs without increasing scan time or requiring additional hardware.The developed technique was tested in phantom experiments and in vivo scans, which showed its capability for suppressing the hyperintensity artifacts without compromising myocardium nulling in the resulting LGE images.

The Role of Clinical Cardiac Magnetic Resonance Imaging in China:Current Status and the Future

Cardiac magnetic resonance(CMR)imaging plays an important role in the diagnosis and management of cardiovascular diseases.The state-of-the-art CMR imaging has many advantages in cardiac imaging,including excellent spatial and temporal resolution,unrestricted imaging fi eld,no exposure to ionizing radiation,excellent tissue contrast,and unique myocardial tissue characterization.Clinical CMR imaging is used during the cardiovascular diagnostic workup in the United States and some European countries.Use of CMR imaging is emerging in hospitals in China and has a promising future.This review briefl y describes the real-world clinical application of CMR imaging in China and discuss obstacles for its future development.

Role of cardiac magnetic resonance imaging in the diagnosis and management of COVID-19 related myocarditis: Clinical and imaging considerations

There is a growing evidence of cardiovascular complications in coronavirusdisease 2019 (COVID-19) patients. As evidence accumulated of COVID-19 mediatedinflammatory effects on the myocardium, substantial attention has beendirected towards cardiovascular imaging modalities that facilitate this diagnosis.Cardiac magnetic resonance imaging (CMRI) is the gold standard for thedetection of structural and functional myocardial alterations and its role inidentifying patients with COVID-19 mediated cardiac injury is growing. Despiteits utility in the diagnosis of myocardial injury in this population, CMRI’s impacton patient management is still evolving. This review provides a framework for theuse of CMRI in diagnosis and management of COVID-19 patients from theperspective of a cardiologist. We review the role of CMRI in the management ofboth the acutely and remotely COVID-19 infected patient. We discuss patientselection for this imaging modality;T1, T2, and late gadolinium enhancementimaging techniques;and previously described CMRI findings in other cardiomyopathieswith potential implications in COVID-19 recovered patients.

Application of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)combined with magnetic resonance spectroscopy(MRS)in prostate cancer diagnosis

Objective The aim of the study was to investigate the application of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)combined with magnetic resonance spectroscopy(MRS)in prostate cancer diagnosis.Methods In the outpatient department of our hospital(Sichuan Cancer Hospital,Chengdu,China),60 patients diagnosed with prostate disease were selected randomly and included in a prostate cancer group,60 patients with benign prostatic hyperplasia were included in a proliferation group,and 60 healthy subjects were included in a control group,from January 2013 to January 2017.Using Siemens Avanto 1.5 T high-field superconducting MRI for DCE-MRI and MRS scans,after the MRS scan was completed,we used the workstation spectroscopy tab spectral analysis,and eventually obtained the crest lines of the prostate metabolites choline(Cho),creatine(Cr),citrate(Cit),and the values of Cho/Cit,and(Cho+Cr)/Cit.Results Participants who had undergone 21-s,1-min,and 2-min dynamic contrast-enhanced MR revealed significant variations among the three groups.The spectral analysis of the three groups revealed a significant variation as well.DCE-MRI and MRS combined had a sensitivity of 89.67%,specificity of 95.78%,and accuracy of 94.34%.Conclusion DCE-MRI combined with MRS is of great value in the diagnosis of prostate cancer.

Cardiac Amyloidosis: The Role of Magnetic Resonance Imaging

Amyloidosis, an infiltrative disease characterized by deposition of high molecular weight insoluble protein has a low detection rate and poor prognosis with congestive heart failure being the most common cause of death. Although definitive diagnosis is based on endomyocardial biopsy, this is rarely performed due to procedural risk and sampling error. Traditional non-invasive imaging, such as transthoracic echocardiography (TTE) and electrocardiogram (ECG) lacks sensitivity detecting the disease in its early stages. This case report demonstrates the utility of cardiac Magnetic Resonance Imaging in addition to traditional imaging modalities in this often clinically challenging problem.

Generalized Nonconvex Low-Rank Algorithm for Magnetic Resonance Imaging (MRI) Reconstruction

In recent years,utilizing the low-rank prior information to construct a signal from a small amount of measures has attracted much attention.In this paper,a generalized nonconvex low-rank(GNLR) algorithm for magnetic resonance imaging(MRI)reconstruction is proposed,which reconstructs the image from highly under-sampled k-space data.In the algorithm,the nonconvex surrogate function replacing the conventional nuclear norm is utilized to enhance the low-rank property inherent in the reconstructed image.An alternative direction multiplier method(ADMM) is applied to solving the resulting non-convex model.Extensive experimental results have demonstrated that the proposed method can consistently recover MRIs efficiently,and outperforms the current state-of-the-art approaches in terms of higher peak signal-to-noise ratio(PSNR) and lower high-frequency error norm(HFEN) values.

Effects of Weight Loss on Pericardial Fat and Left Ventricular Mass Assessed with Cardiac Magnetic Resonance Imaging in Morbid Obesity

Background: Obesity is a risk factor for cardiovascular disease and mortality. Significant weight loss has beneficial effects on left ventricular structure, in particular on regression of left ventricular hypertrophy (LVH). We therefore evaluated the consequences of significant weight loss on left ventricular morphology, hemodynamics and pericardial fat. Methods: We performed volumetric cardiac magnetic resonance (CMR) imaging before and after significant weight loss due to laparoscopic adjustable gastric banding (LAGB). CMR was used to measure cardiac mass, volume and function, as well as to quantify pericardial fat. Results: Eleven patients (age 40.5 ± 10 yrs, body mass index 42.5 ± 3.9 kg/m2) underwent CMR imaging before and a median 15.4 months after gastric banding. The BMI declined by 9.3 ± 3.3 kg/m2 (p Discussion: Significant weight loss in obesity is accompanied by a marked regression of LVH, with no apparent change in cardiac volume or function. The local effect of a diminished amount of pericardiac fat tissue may be more important than absolute weight loss with respect to the regression of LVH in obesity.

Cardiac involvement in hydrocarbon inhalant toxicity--role of cardiac magnetic resonance imaging:A case report

BACKGROUND We report a patient who was diagnosed with toxic myopericarditis secondary to hydrocarbon abuse using cardiac magnetic resonance imaging(CMR).CASE SUMMARY A 25-year-old male presented to emergency department with chest pain for 3 d.Patient also reported sniffing hydrocarbon containing inhalant for the last 1 year.Labs showed elevated troponin and electrocardiography was suggestive of acute pericarditis.Echocardiogram showed left ventricular(LV)ejection fraction(EF)of 40%.Given patient’s troponin elevation and reduced EF,cardiac catheterization was performed which showed normal coronaries.CMR was performed for myocardial infarction with non-obstructive coronary arteries evaluation.CMR showed borderline LV function with edema in mid and apical LV suggestive of myocarditis.CONCLUSION CMR can be used to diagnose toxic myopericarditis secondary to hydrocarbon abuse.

Role of cardiac magnetic resonance imaging in troponinemia syndromes

Cardiac magnetic resonance imaging(MRI)is an evolving technology,proving to be a highly accurate tool for quantitative assessment.Most recently,it has been increasingly used in the diagnostic and prognostic evaluation of conditions involving an elevation in troponin or troponinemia.Although an elevation in troponin is a nonspecific marker of myocardial tissue damage,it is a frequently ordered investigation leaving many patients without a specific diagnosis.Fortunately,the advent of newer cardiac MRI protocols can provide additional information.In this review,we discuss several conditions associated with an elevation in troponin such as myocardial infarction,myocarditis,Takotsubo cardiomyopathy,coronavirus disease 2019 related cardiac dysfunction and athlete’s heart syndrome.

Correlation between myocardial infarction activity assessed by cardiac magnetic resonance imaging and the evolution of cardiac function after PCI

Objective:To investigate the correlation of cardiac magnetic resonance imaging(MRI)in the assessment of myocardial activity in patients with myocardial infarction and the outcome of cardiac function after PCI.Methods:30 patients with myocardial infarction(MI)who had complete clinical and imaging data from July 2016 to December 2018 after PCI were analyzed retrospectively.MR and echocardiogram were performed before and 6 months after PCI,and the parameters related to left ventricular function were measured by post-processing software of MRI workstation.The left ventricular transmural degree of CMR late gadolinium enhancement was compared with the left ventricular wall motion degree of 6-month echocardiography as a standard to judge the viable myocardium.Result:There were 193 left ventricular segmental abnormalities in 30 cases,including 121 viable myocardium and 72 non viable myocardium in CMR-LGE before operation.Six months after PCI,echocardiography showed that 125 of 193 abnormal segments of left ventricle detected by CMR-LGE before PCI were viable myocardium and 68 were non viable myocaridium.The sensitivity and specificity of CMR-LGE to determinate of viable myocardium were 92.0%and 91.1%respectively.The larger the non-viable myocardial area of the left ventricular wall,the worse the recovery of wall motion ability,and there was a negative correlation between them(r=0.416,P<0.05).The first-pass perfusion time in CMR-LEG region was significantly longer than that in normal myocardial region(4.85(+)1.51)s and(3.79(+)1.73)s,respectively.The difference was statistically significant(t=5.191,P<0.05).Conclusion:MRI can evaluate the myocardial activity of myocardial infarction,reflect the range of viable myocardium,and provide imaging basis for clinical treatment and prognosis.

Computer-aided differential diagnosis system for Alzheimer’s disease based on machine learning with functional and morphological image features in magnetic resonance imaging

Alzheimer’s disease (AD) is a dementing disorder and one of the major public health problems in countries with greater longevity. The cerebral cortical thickness and cerebral blood flow (CBF), which are considered as morphological and functional image features, respectively, could be decreased in specific cerebral regions of patients with dementia of Alzheimer type. Therefore, the aim of this study was to develop a computer-aided classification system for AD patients based on machine learning with the morphological and functional image features derived from a magnetic resonance (MR) imaging system. The cortical thicknesses in ten cerebral regions were derived as morphological features by using gradient vector trajectories in fuzzy membership images. Functional CBF maps were measured with an arterial spin labeling technique, and ten regional CBF values were obtained by registration between the CBF map and Talairach atlas using an affine transformation and a free form deformation. We applied two systems based on an arterial neural network (ANN) and a support vector machine (SVM), which were trained with 4 morphological and 6 functional image features, to 15 AD patients and 15 clinically normal (CN) subjects for classification of AD. The area under the receiver operating characteristic curve (AUC) values for the two systems based on the ANN and SVM with both image?features were 0.901 and 0.915, respectively. The AUC values for the ANN-and SVM-based systems with the morphological features were 0.710 and 0.660, respectively, and those with the functional features were 0.878 and 0.903, respectively. Our preliminary results suggest that the proposed method may have potential for assisting radiologists in the differential diagnosis of AD patients by using morphological and functional image features.

Brain Tumor Classification in Magnetic Resonance Images Using Deep Learning and Wavelet Transform

A brain tumor is a mass of abnormal cells in the brain. Brain tumors can be benign (noncancerous) or malignant (cancerous). Conventional diagnosis of a brain tumor by the radiologist is done by examining a set of images produced by magnetic resonance imaging (MRI). Many computer-aided detection (CAD) systems have been developed in order to help the radiologists reach their goal of correctly classifying the MRI image. Convolutional neural networks (CNNs) have been widely used in the classification of medical images. This paper presents a novel CAD technique for the classification of brain tumors in MRI images. The proposed system extracts features from the brain MRI images by utilizing the strong energy compactness property exhibited by the Discrete Wavelet Transform (DWT). The Wavelet features are then applied to a CNN to classify the input MRI image. Experimental results indicate that the proposed approach outperforms other commonly used methods and gives an overall accuracy of 99.3%.

MAGNETIC RESONANCE IMAGES OF THE HYPOTHALAMIC-PITUITARY AREA IN IDIOPATHIC GROWTH DEFICIENCY

In order to describe the magnetic resonance imaging (MRI) findings in hypothaiamic-pituitary area and its clinical relevance in patients with idiopathic growth hormone deficiency (IGHD), the MR imagings of 26 patients with IGHD were analyzed. On MRI, 24 out of 26 cases (92. 3%) showed apparent pituitary upper margin depresslon t 8 out of 26 cases (30. 8%) showed defmlte pituitary stalk transeetlon; 22 out of 26 cases (84. 6%) showed absence of the normal posterior pituitary bright spot. The bright lipidlike signal on TIW1 images at the median eminence distal to the breaking point (so-called ectople posterior lobe) was found in 4 out of 26 cases (15.4%). According to the MRI findings of iehe pituitary stalks, the 26 cases were divided into three groups; group A of 8 cases (31%) characterized by the definite transaction of stalk; group B of 13 cases (50%) defined by the possible stalk transection; and group C of 5 eases (19%) with no definite stalk transection. MRI findings were consistent with the clinical and endocrine tests. The stalk transection was staristically significantly difference in insulin test, L-dopa/p test, and height standard deviation score (P<0. 05). The MRI of hypothalamic-pltuitary area may differentiate partial IGHD form stalk-transected,doubtful transection and without transection.

Targeted prostate biopsy： value of multiparametric magnetic resonance imaging in detection of localized cancer

Prostate cancer is the second most common cancer in men, with 1.1 million new cases worldwide reported by the World Health Organization in one recent year. Transrectal ultrasound （TRUS）-guided biopsy has been used for the diagnosis of prostate cancer for over 2 decades, but the technique is usually blind to cancer location. Moreover, the false negative rate of TRUS biopsy has been reported to be as high as 47%. Multiparametric magnetic resonance imaging （mp-MRI） includes T1- and T2-weighted imaging as well as dynamic contrast-enhanced （DCE） and diffusion-weighted imaging （DWI）. mp-MRI is a major advance in the imaging of prostate cancer, enabling targeted biopsy of suspicious lesions. Evolving targeted biopsy techniquesmincluding direct in-bore biopsy, cognitive fusion and software-based MRI-ultrasound （MRI-US） fusion--have led to a several-fold improvement in cancer detection compared to the earlier method. Importantly, the detection of clinically significant cancers has been greatly facilitated by targeting, compared to systematic biopsy alone. Targeted biopsy via MRI-US fusion may dramatically alter the way prostate cancer is diagnosed and managed.

Impact of cardiac magnet resonance imaging on management of ventricular septal rupture after acute myocardial infarction

A 74-year-old man was admitted to the cardiac catheterization laboratory with acute myocardial infarction. After successful angioplasty and stent implantation into the right coronary artery, he developed cardiogenic shock the following day. Echocardiography showed ventricular septal rupture. Cardiac magnet resonance imaging (MRI) was performed on the critically ill patient and provided detailed information on size and localization of the ruptured septum by the use of fast MRI sequences. Moreover, the MRI revealed that the ventricular septal rupture was within the myocardial infarction area, which was substantially larger than the rupture. As the patient's condition worsened, he was intubated and had intra-aortic balloon pump implanted, and extracorporeal membrane oxygenation was initiated. During the following days, the patient's situation improved, and surgical correction of the ventricular septal defect could successfully be performed. To the best of our knowledge, this case report is the first description of postinfarction ventricular septal rupture by the use of cardiac MRI in an intensive care patient with cardiogenic shock and subsequent successful surgical repair.