Yi Huan

Dynamic contrast-enhanced MRI of benign prostatic hyperplasia and prostatic carcinoma : correlation with angiogenesis

AIM To investigate the diagnostic and differential diagnostic values of dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) in prostatic diseases, and to investigate the correlation between the parameters of SI-T curves and angiogenesis. MATERIALS AND METHODS Twenty-one patients with proven prostatic carcinoma (Pca) and 29 patients with proven benign prostatic hyperplasia (BPH) were examined using DCE MRI. Diagnostic characteristics for differentiation were examined using threshold values for maximum peak time, enhancement degree, and enhancement rate. Then, the signal intensity-time curves (SI-T curves) were analysed, and the correlations between the parameters of SI-T curves and the expression levels of vascular endothelial growth factor (VEGF) and microvascular density (MVD) were investigated. All patents underwent prostatectomy. DCE MRI and histological findings were correlated. RESULTS Pca showed stronger enhancement with an earlier peak time, higher enhancement, and enhancement rate (p<0.05). Regarding the type of SI-T curves, in the BPH group six were type A, 10 were type B, and 13 were type C, whereas in the Pca group, 14 were type A, six were type B, and only one was type C (Chi-square test, chi2=13.57, P<0.005). The VEGF and MVD expression levels of Pca were higher than those of BPH. Peak time was negatively correlated with the expression levels of VEGF and MVD, whereas the enhancement degree and enhancement rate showed positive correlations (Pearson correlation, p<0.05). CONCLUSION Based on T2-weighted imaging, DCE MRI curves can help to differentiate benign from malignant prostate tissue. In the present study the type C curve was rarely seen with malignant disease, but these results need confirmation.

Seminal vesicle invasion in prostate cancer: prediction with combined T2-weighted and diffusion-weighted MR imaging

The aim of this study was to evaluate the usefulness of diffusion-weighted imaging (DWI) in detecting seminal vesicle invasion (SVI). A total of 283 patients underwent conventional MRI and DWI before prostate cancer surgery. The apparent diffusion coefficient (ADC) values of all PCa foci, SVI and seminal vesicle were measured. T2 images alone and then T2 images combined with DWI were scored for the likelihood of SVI. The area under the receiver operating characteristic curve (AUC) was used to assess accuracy. Statistical significance was inferred at P < 0.05. On pathological analysis, 39 patients had SVI. The ADC values of SVI were significantly lower than those of SV. The AUC for T2-weighted imaging plus DW imaging (0.897) was significantly larger (P < 0.05) than that for T2-weighted imaging alone (0.779). T2 images combined with DWI shows significantly higher accuracy than T2-weighted imaging alone in the detection of SVI.

Combined T2-weighted and diffusion-weighted MRI for diagnosis of urinary bladder invasion in patients with prostate carcinoma.

To retrospectively determine the diffusion‐weighted imaging (DWI) characteristics and apparent diffusion coefficient (ADC) values of prostate carcinoma (PCa) with urinary bladder invasion, and to compare the accuracy of T2‐weighted MRI alone and T2 combined with DWI for predicting urinary bladder invasion.

MRI features of pediatric cerebral paragonimiasis in the active stage.

We retrospectively reviewed the MR images of the brains of six children (age = 5–13 years) who had cerebral paragonimiasis in the early active stage. Diagnosis was based on a positive antibody test enzyme‐linked immunosorbent assay (ELISA) for paragonimiasis in serum. The most common finding (in five patients) was irregular hemorrhage of various degrees. Moreover, in three cases some multiple irregular lesions with surrounding edema appeared to be conglomerated and aggregated. The rare appearance (in one patient) was a “tunnel sign,” which showed the migrating track of the adult worm. In one patient with abscess and minimal hemorrhage, diffusion‐weighted imaging (DWI) showed a heterogeneous high signal of lesions. Other findings included slight (one patient) or marked (one patient) irregular contrast enhancement, and large edematous areas surrounding small centers of hemorrhage (two patients). MR findings of conglomerated lesions with hemorrhage or tunnel sign may help to establish the diagnosis of active‐stage cerebral paragonimiasis. J. Magn. Reson. Imaging 2006.

Normalized Upper Cervical Spinal Cord Atrophy in Multiple Sclerosis

To find an optimal normalizing factor for upper cervical spinal cord area (UCCA) and to establish whether, in a cross‐sectional study, the normalized UCCA correlates better with the neurological disability than the absolute measurement in multiple sclerosis patients.

A meta-analysis of use of Prostate Imaging Reporting and Data System Version 2 (PI-RADS V2) with multiparametric MR imaging for the detection of prostate cancer

ObjectivesThis meta-analysis was undertaken to review the diagnostic accuracy of PI-RADS V2 for prostate cancer (PCa) detection with multiparametric MR (mp-MR).MethodsA comprehensive literature search of electronic databases was performed by two observers independently. Inclusion criteria were original research using the PI-RADS V2 system in reporting prostate MRI. The methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Data necessary to complete 2 × 2 contingency tables were obtained from the included studies.ResultsThirteen studies (2,049 patients) were analysed. This is an initial meta-analysis of PI-RADs V2 and the overall diagnostic accuracy in diagnosing PCa was as follows: pooled sensitivity, 0.85 (0.78–0.91); pooled specificity, 0.71 (0.60–0.80); pooled positive likelihood ratio (LR+), 2.92 (2.09–4.09); pooled negative likelihood ratio (LR–), 0.21 (0.14–0.31); pooled diagnostic odds ratio (DOR), 14.08 (7.93–25.01), respectively. Positive predictive values ranged from 0.54 to 0.97 and negative predictive values ranged from 0.26 to 0.92.ConclusionCurrently available evidence indicates that PI-RADS V2 appears to have good diagnostic accuracy in patients with PCa lesions with high sensitivity and moderate specificity. However, no recommendation regarding the best threshold can be provided because of heterogeneity.Key Points• PI-RADS V2 shows good diagnostic accuracy for PCa detection.• Initially pooled specificity of PI-RADS v2 remains moderate.• PCa detection is increased by experienced radiologists.• There is currently a high heterogeneity in prostate diagnostics with MRI.

Temporal evolution of spinal cord infarction in an in vivo experimental study of canine models characterized by diffusion-weighted imaging

To determine the temporal evolution of diffusion abnormalities of in vivo experimental spinal cord infarction.

Apparent diffusion coefficients of normal uterus in premenopausal women with 3.0-T magnetic resonance imaging.

Purpose To investigate the apparent diffusion coefficients (ADCs) of the normal uterine zonal structures (myometrium, endometrium, and junctional zone) during different phases of the menstrual cycle among premenopausal women with different age groups. Materials and Methods Magnetic resonance (MR) images of 67 healthy women were obtained during the midproliferative and midsecretory phases. They were further divided into 3 age groups: group A (age range, 20–29 years); group B (age range, 30–39 years), and group C (mean age, 44.62 years; age range, 40–49 years). All the women underwent 3.0-T MR scanning twice. The ADC values were compared among each uterine zonal structure and 3 age groups and were calculated between the midproliferative and midsecretory phase. Results The ADC values among each uterine zonal structures were significantly different from one another (P < 0.001). The ADC values for endometrium in women in their 30s were higher than those in their 20s and in their 30s during the midproliferative and midsecretory phases (P < 0.05), and the ADC values for endometrium in each age groups were lower during the midproliferative phase than those during the midsecretory phase (P < 0.05), but there were no statistical differences in the myometrium and the junctional zone between the 2 phases or among age groups (P > 0.05). Conclusion These preliminary results suggested that the zone, age, and phase of the menstrual cycle in premenopausal women should be considered when interpreting the ADC values of uterine structures (especially for endometrium).

A multicenter, randomized, controlled, single-blind comparison phase III study to determine the efficacy and safety of gadobutrol 1.0 M versus gadopentetate dimeglumine following single injection in patients referred for contrast-enhanced MRI of the body regions or extremities

To demonstrate the noninferiority of gadobutrol‐enhanced magnetic resonance imaging (MRI) compared with gadopentetate dimeglumine‐enhanced MRI in Asian patients referred for contrast‐enhanced imaging of the body or extremities.

Efficacy and Safety of Gadobutrol (1.0 M) versus Gadopentetate Dimeglumine (0.5 M) for Enhanced MRI of CNS Lesions: A Phase III, Multicenter, Single-Blind, Randomized Study in Chinese Patients

The aim of this study was to compare the efficacy and safety of macrocyclic gadobutrol (1.0 M) with linear gadopentetate dimeglumine (0.5 M) for contrast-enhanced magnetic resonance imaging (MRI) of central nervous system (CNS) lesions in Chinese patients (N = 147) with known or suspected CNS lesions, who were enrolled in this single-blind, randomized, parallel-group study. Three blinded independent readers evaluated all efficacy variables. The primary efficacy variable was the difference between the two agents for the change in contrast-to-noise ratio (CNR) between non-enhanced and contrast-enhanced scans of lesions. Secondary outcomes included mean change in number of lesions detected before and after contrast enhancement, diagnostic confidence, and safety and tolerability parameters. Gadobutrol was non-inferior to gadopentetate dimeglumine in respect to the difference in the mean change in CNR (6.94; 95% confidence interval [CI] lower limit: -3.90; predefined maximum 95% CI lower limit: -6.52). The mean change in the number of CNS lesions detected was greater with gadobutrol versus gadopentetate dimeglumine (1.2 vs. 0.2 lesions). Diagnostic confidence was classified as ‘high’ for more patients with gadobutrol versus gadopentetate dimeglumine by the investigators (58.8% vs. 55.4%) and by the three blinded readers (63.6% vs. 55.7%, 23.7% vs. 18.0% and 81.7% vs. 81.0%). Both agents were well tolerated by participating patients. We concluded that in Chinese patients with CNS lesions, gadobutrol (1.0 M) was as effective and well tolerated in contrast-enhanced MRI as gadopentetate dimeglumine (0.5 M). Gadobutrol provided improved visualization of CNS lesions compared with gadopentetate dimeglumine, with a comparable tolerability profile.