There are various examination methods for cardiovascular diseases. Non-invasive diagnosis and prognostic information acquisition are the current research hotspots of related imaging examinations. Positron emission tomography (PET)/magnetic resonance imaging (MRI) is a new advanced fusion imaging technology that combines the molecular imaging of PET with the soft tissue contrast function of MRI to achieve their complementary advantages. This article briefly introduces several major aspects of cardiac PET/MRI in the diagnosis of cardiovascular disease, including atherosclerosis, ischemic cardiomyopathy, nodular heart disease, and myocardial amyloidosis, in order to promote cardiac PET/MRI to be more widely used in precision medicine in this field.
ObjectiveTo investigate the changes and clinical significance of cardiac structure and function evaluation by cardiac magnetic resonance imaging (CMR) for patients with pectus excavatum deformity at preoperation. MethodsWe retrospectively analyzed 54 patients (24 children and 30 adults) who underwent pectus excavatum surgery from June 2012 to June 2014. There were 48 males and 6 females at age of 7-33 (19.08±5.17) years. All the patients underwent CMR using 1.5 Tesla scanner for evaluation of compressing and displacement of the heart. The major and minor dimensions of right ventricle were measured. The right ventricle end-diastole volume (RVEDV), right ventricle end-systolic volume (RVESV), and right ventricle ejection fraction (RVEF) were also recorded and analyzed. ResultsThe heart compression and displacement occurred in 83.3% of the children group and 90.0% of the adults group. The extent of heart displacement in the adults was more serious than that in the children (76.86%±13.30% vs. 67.99%±8.15%, P<0.05). The structure of right ventricle were striking distorted because right atrum or right ventricule below valve ring was compressed locally, with the major dimension of right ventricle obviously increased, and the minor dimension of right ventricle obviously decreased. The indices of right ventricle major dimension and right ventricle minor dimension were 61.14±0.44 mm/m2 and 14.82±2.52 mm/m2 in the children, 49.54±15.40 mm/m2 and 18.90 ±3.14 mm/m2 in the adults. The RVEDV and RVESV were significantly higher in the adults than those in the children (139.09±29.08 ml vs. 121.50±31.27 ml; 73.61±16.05 ml vs. 64.92±19.28 ml; P<0.05). RVEF was similar between the children and the adults (45.29%±4.14% vs. 46.30±6.09%). The patients' symptoms disappeared after correction of pectus excavatum. ConclusionCMR is an useful method for evaluating right ventricular structure and functions in patients with cardiac compression and distortion by pectus excavatum before operation, which can bring strong indications for pectus excavatum repair surgery.
Objective To assess value and limitations of non-invasive methods in assessing liver fibrosis．Methods By summarized current situation and advancement of serum fibrotic markers, ultrasound, CT and MRI in assessing liver fibrosis, we investigated their value and limitations. Results In addition to diagnosis, non-invasive methods of assessing liver fibrosis assess severity of liver fibrosis. For liver fibrosis, however, non-invasive methods can not monitor effectively reaction to therapy and progression. Conclusion Non-invasive methods play important roles in diagnosis and assessing severity of liver fibrosis, and reduce the need of liver biopsy.
Objective To investigate the application of the dynamic contrast enhanced MRI (DCE-MRI ) combined with magnetic resonance spectroscopy (MRS) in the diagnosis of prostate cancer. Method A total of 60 patients with prostate cancer and 60 patients with benign prostatic hyperplasia diagnoses in Sichuan Cancer Hospital from January 2011 to January 2014 were included as prostate cancer group and proliferative group respectively. Sixty healthy individuals during the same period were included as the control group. We used Siemens Avanto 1.5 T high field superconducting MRI for DCE-MRI scan and MRS scan. After the MRS scan was finished, we used the workstation spectroscopy tab spectral analysis. Eventually we got the crest lines of prostate metabolites choline (Cho), creatine (Cr) and citrate (Cit). Then we calculated Cho/Cit, (Cho+Cr)/Cit and their average. Results Comparing the signal value in 21 seconds, 1 minute, 2 minutes of DCE-MRI, the differences among the three groups were statistically significant (P<0.05). Comparing the results of spectral analysis, the differences among the three groups were statistically significant (P<0.05). The sensitivity was 89.67%, the specificity was 95.45% and the accuracy was 94.34% when using DCE-MRI combined with MRS. Conclusion DCE-MRI combined with MRS greatly improves the sensitivity, specificity and accuracy of the diagnosis of prostate cancer; it has a great application value in the diagnosis of prostate cancer.
Solitary pulmonary nodule (SPN) is defined as a rounded opacity≤3 cm in diameter surrounded by lung parenchyma. The majority of smokers who undergo thin-section CT have SPNs, most of which are smaller than 7 mm. In the past, multiple follow-up examinations over a two-year period, including CT follow-up at 3, 6, 12, 18, and 24 months, were recommended when such nodules are detected incidentally. This policy increases radiation burden for the affected population. Nodule features such as shape, edge characteristics, cavitation, and location have not yet been found to be accurate for distinguishing benign from malignant nodules. When SPN is considered to be indeterminate in the initial exam, the risk factor of the patients should be evaluated, which includes patients' age and smoking history. The 2005 Fleischner Society guideline stated that at least 99% of all nodules 4 mm or smaller are benign; when nodule is 5-9 mm in diameter, the best strategy is surveillance. The timing of these control examinations varies according to the nodule size (4-6, or 6-8 mm) and the type of patients, specifically at low or high risk of malignancy concerned. Noncalcified nodules larger than 8 mm diameter bear a substantial risk of malignancy, additional options such as contrast material-enhanced CT, positron emission tomography (PET), percutaneous needle biopsy, and thoracoscopic resection or videoassisted thoracoscopic resection should be considered.
Aiming at motion artifacts and off-resonance artifacts in multi-shot diffusion magnetic resonance imaging (MRI), we proposed a joint correction method in this paper to correct the two kinds of artifacts simultaneously without additional acquisition of navigation data and field map. We utilized the proposed method using multi-shot variable density spiral sequence to acquire MRI data and used auto-focusing technique for image deblurring. We also used direct method or iterative method to correct motion induced phase errors in the process of deblurring. In vivo MRI experiments demonstrated that the proposed method could effectively suppress motion artifacts and off-resonance artifacts and achieve images with fine structures. In addition, the scan time was not increased in applying the proposed method.
Objective To observe the results of function MRI and perimetry in patients with visual pathway diseases.Methods Three patients (6 eyes) with pituitary adenoma and craniopharyngioma diagnosed via pathological examination and three healthy volunteers aged from 24 to 30 were collected. The best corrected visual acuity was nonlight perception1.0 in the 6 sick eyes and 1.0 in the healthy eyes; all the involved individuals had no other ocular diseases except myopia and without any contraindications of MRI. Common tests including the best visual acuity, fundus test by direct or indirect ophthalmoscope, center static visual field tested by Octopus 101 perimeter, program 32, tendency oriented perimetry were performed. The visual stimulation subtended a field of view of about 12 degrees，consisted of high contrast and drifting checkerboards. MRI parameters: GE signa VH/i 30T scanner. Functional data: GRE-EPI sequence，20 slices lying perpendicular to the calcarine sulcus. Anatomical data was obtained using 3DSPGR sequence to acquire high resolution. The cortical surface was unfolded and then cut and inflated. Functional data was presented to the inflated surface and subsequently analyzed by AFNI software.Results In six eyes, three had temporal defects, two had upper temporal visual field defects, and the other one did not finish the visual field test. The retinotopic representations of health adults were obtained by using the phaseencoded visual stimulation. The Eccentricity coordinate maps showed that foveal representations lay in the occipital poles and the representations appeared further anterior as eccentricity increased. The polar angle coordinate maps showed that early retinotopically organized areas had a representation of visual field. The visual cortex beneath the calcarine sulcus matched with the upper visual field of the opposite side and which upon the calcarine sulcus matched with the under visual field of the opposite side. Less or no visual cortex response was revealed in the patients′ function MRI or the response in injury side was vanished. The visual cortex response related with the visual field defects could not be induced in function MRI.Conclusion There is a good correlation between function MRI data and the results of perimetric evaluation. The function MRI can show the visual cortex response correlated with the visual field defects of the patients with visual pathway diseases.
Objective To review the current status of magnetic resonance imaging (MRI) techniques in the evaluation of hepatic fibrosis. Methods The application and recent advances of various kinds of MRI techniques in evaluating hepatic fibrosis were summarized by literature review. Results The state-of-the-art of MRI evaluating of hepatic fibrosis included common contrast-enhanced MRI, double contrast-enhanced MRI, and various functional MRI techniques. Common contrast-enhanced MRI could detect morphological changes of the liver, but little value in phasing. Double contrast-enhanced MRI markedly increased the contrast to noise ratio. Except diagnosis liver fibrosis, functional MRI also could phase it by its serverity. Conclusion MRI techniques, especially those functional MRI techniques, are advancing very fast and have very great potentiality in both the diagnosis and severity assessment of hepatic fibrosis.
ObjectiveTo investigate the diagnostic value of MRI hip joint unilateral oblique coronary scanning in the diagnosis of femoroacetabular impingement (FAI).MethodsFrom February to October 2014, 75 patients with hip joint pain who were highly suspected of FAI after X-ray or CT examination were selected as subjects. Using Siemens 1.5 T MR, fat-suppressed T2-weighted imaging sequences, T1-weighted imaging sequences, and proton density-weighted imaging sequences were used. For each patient two scan methods were used. Method A: on the sagittal image of the hip joint, the line of sight was parallel to the oblique coronal plane scan of the (one-sided) long axis of the femoral neck. Method B: on the cross-sectional image of the hip joint, the positioning line was parallel to the conventional hip joint coronal scan of the left and right femoral heads. McNemar test was used to compare the detection rates of FAI of the two methods.ResultThe detection rate of FAI of A-scanning [62.6% (47/75)] was higher than that of B-scanning [30.6% (23/75)], and the difference was statistically significant (P<0.001).ConclusionAn image obtained from a diagonal coronal scan parallel to the long axis of the femoral neck can more fully display the pathological changes of the acetabular labrum and the anatomy of the femoral head and neck joints, and the damage of the femoral head and neck junction, which provides a more reliable imaging basis for the clinician to diagnose FAI.