Evaluation of the Prostate Imaging Reporting and Data System for Magnetic Resonance Imaging Diagnosis of Prostate Cancer in Patients with Prostate-specific Antigen <20 ng/ml / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The European Society of Urogenital Radiology has built the Prostate Imaging Reporting and Data System (PI-RADS) for standardizing the diagnosis of prostate cancer (PCa). This study evaluated the PI-RADS diagnosis method in patients with prostate-specific antigen (PSA) <20 ng/ml.</p><p><b>METHODS</b>A total of 133 patients with PSA <20 ng/ml were prospectively recruited. T2-weighted (T2WI) and diffusion-weighted (DWI) magnetic resonance images of the prostate were acquired before a 12-core transrectal prostate biopsy. Each patient's peripheral zone was divided into six regions on the images; each region corresponded to two of the 12 biopsy cores. T2WI, DWI, and T2WI + DWI scores were computed according to PI-RADS. The diagnostic accuracy of the PI-RADS score was evaluated using histopathology of prostate biopsies as the reference standard.</p><p><b>RESULTS</b>PCa was histologically diagnosed in 169 (21.2%) regions. Increased PI-RADS score correlated positively with increased cancer detection rate. The cancer detection rate for scores 1 to 5 was 2.8%, 15.0%, 34.6%, 52.6%, and 88.9%, respectively, using T2WI and 12.0%, 20.2%, 48.0%, 85.7%, and 93.3%, respectively, using DWI. For T2WI + DWI, the cancer detection rate was 1.5% (score 2), 13.5% (scores 3-4), 41.3% (scores 5-6), 75.9% (scores 7-8), and 92.3% (scores 9-10). The area under the curve for cancer detection was 0.700 (T2WI), 0.735 (DWI) and 0.749 (T2WI + DWI). The sensitivity and specificity were 53.8% and 89.2%, respectively, when using scores 5-6 as the cutoff value for T2WI + DWI.</p><p><b>CONCLUSIONS</b>The PI-RADS score correlates with the PCa detection rate in patients with PSA <20 ng/ml. The summed score of T2WI + DWI has the highest accuracy in detection of PCa. However, the sensitivity should be further improved.</p>

Amide proton transfer magnetic resonance imaging of Alzheimer's disease at 3.0 Tesla: a preliminary study / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Amide proton transfer (APT) imaging has recently emerged as an important contrast mechanism for magnetic resonance imaging (MRI) in the field of molecular and cellular imaging. The aim of this study was to evaluate the feasibility of APT imaging to detect cerebral abnormality in patients with Alzheimer's disease (AD) at 3.0 Tesla.</p><p><b>METHODS</b>Twenty AD patients (9 men and 11 women; age range, 67-83 years) and 20 age-matched normal controls (11 men and 9 women; age range, 63-82 years) underwent APT and traditional MRI examination on a 3.0 Tesla MRI system. The magnetic resonance ratio asymmetry (MTR asym ) values at 3.5 ppm of bilateral hippocampi (Hc), temporal white matter regions, occipital white matter regions, and cerebral peduncles were measured on oblique axial APT images. MTR asym (3.5 ppm) values of the cerebral structures between AD patients and control subjects were compared with independent samples t-test. Controlling for age, partial correlation analysis was used to investigate the associations between mini-mental state examination (MMSE) and the various MRI measures among AD patients.</p><p><b>RESULTS</b>Compared with normal controls, MTR asym (3.5 ppm) values of bilateral Hc were significantly increased in AD patients (right 1.24% ± 0.21% vs. 0.83% ± 0.19%, left 1.18% ± 0.18% vs. 0.80%± 0.17%, t = 3.039, 3.328, P = 0.004, 0.002, respectively). MTR asym (3.5 ppm) values of bilateral Hc were significantly negatively correlated with MMSE (right r = -0.559, P = 0.013; left r = -0.461, P = 0.047).</p><p><b>CONCLUSIONS</b>Increased MTR asym (3.5 ppm) values of bilateral Hc in AD patients and its strong correlations with MMSE suggest that APT imaging could potentially provide imaging biomarkers for the noninvasive molecular diagnosis of AD.</p>

Diagnostic value of interictal diffusion-weighted imaging in evaluation of intractable temporal lobe epilepsy / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To explore the ability of interictal diffusion-weighted imaging (DWI) to localize the temporal lobe of seizure origin and to predict postoperative seizure control in patients with temporal lobe epilepsy (TLE).</p><p><b>METHODS</b>Twenty-seven patients with intractable TLE considered for surgery and 19 healthy volunteers were studied with conventional magnetic resonance imaging (MRI) and DWI. Apparent diffusion coefficients (ADCs) of bilateral hippocampi in both TLE patients and control subjects were obtained. Lateralization to either temporal lobe with hippocampal ADC was based on the threshold values derived from +/- SD of right/left ratios in normal subjects. And the postoperative pathology was reviewed.</p><p><b>RESULTS</b>Hippocampal ADCs were higher on the side of surgery compared with those on the contralateral side as well as the ipsilateral side in control subjects [resected side (109.8 +/- 7.3) x 10(-5) cm2/s, contralateral side (91.7 +/- 4.7) x 10(-5) cm2/s, control subjects (81.6 +/- 5.2) x 10(-5) cm2/s, all P < 0.01]. Right/left hippocampal ADC ratio and conventional MRI lateralized to the operated temporal lobe in 21 of 27 (77.8%) and in 18 of 27 (66.7%) patients. Lateralization to the surgical side was not associated with postoperative seizure control with right/left hippocampal ADC ratio (P > 0.05).</p><p><b>CONCLUSIONS</b>Conventional MRI is a sensitive method to detect hippocampal sclerosis. Accuracy of the right/left hippocampal ADC ratio for lateralizing to the side of surgery is very high, but it isn't a better predictor of surgical outcome.</p>

Functional magnetic resonance imaging and immunohistochemical study of hypothalamic function following oral glucose ingestion in rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The hypothalamus plays a central role in the regulation of metabolism by sensing metabolic demands and releasing regulatory neurotransmitters. This study investigated the response of the hypothalamus to glucose ingestion in rats by blood oxygen level-dependent functional magnetic resonance imaging (BOLD-fMRI) and immunohistochemical techniques to determine the role of the hypothalamus in glyco-regulation during disturbances in carbohydrate metabolism.</p><p><b>METHODS</b>The signal intensity of the hypothalamus was monitored by fMRI for 60 minutes after oral glucose intake in 48 healthy rats (age 14 months), which included 24 normal weight rats (weighing (365 +/- 76.5) g) and 24 overweight rats (weighing (714 +/- 83.5) g). Then, 12 rats (6 normal, 6 overweight) underwent a repeat fMRI scan after consuming an equivalent amount of water without glucose on a separate day. The procedure for fMRI with water intake was the same as for glucose ingestion. fMRI data was processed using time cluster analysis and intensity averaging method. After fMRI, the expression of neuropeptide Y (NPY) and 5-hydroxytryptamine (5-HT) in the hypothalamus of all rats was determined by immunohistochemistry. Positive cells for NPY or 5-HT were counted.</p><p><b>RESULTS</b>There was a transient, but significant, decrease in fMRI signal intensity in all rats (mean (3.12 +/- 0.78)%) in the hypothalamus within 19.5 - 25.5 minutes of oral glucose ingestion. In overweight rats, the decrease in signal intensity in response to the glucose ingestion was more markedly attenuated than that observed in normal weight rats ((2.2 +/- 1.5)% vs (4.2 +/- 0.7)% inhibition, t = 2.12, P < 0.05). There was no significant response in the hypothalamus after oral water ingestion. The percentage of NPY positive cells in obese rats were slightly lower than those in control group (21% vs 23%, t = 0.71, P > 0.05); but there was no significant difference between the two groups; the percentage of 5-HT positive cells in obese rats were significantly lower than those in the control group (22% vs 31%, t = 3.25, P < 0.01).</p><p><b>CONCLUSIONS</b>There is a transient, but significant, decrease in BOLD signal intensity in the hypothalamus following glucose ingestion, which is similar to that observed in humans. The response of the hypothalamus to glucose ingestion was different in overweight and normal weight rats. The percentage of NPY positive cells in obese rats were lower than those in the control group, although this difference was not statistically significant. The percentage of 5-HT positive cells in obese rats was significantly lower than those in the control group.</p>

Differentiation between benign prostatic hyperplasia and prostate cancer in the transitional zone evaluated by 1H magnetic resonance spectroscopic imaging / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To quantitatively evaluate the metabolic changes of benign prostatic hyperplasia (BPH) and prostate cancer in the transitional zone using magnetic resonance spectroscopic imaging (MRSI), and to analyze the characteristics and differences of the spectra in this zonal area.</p><p><b>METHODS</b>Eighteen patients with prostate cancer in the transitional zone underwent magnetic resonance imaging (MRI)/MRSI examinations. The (Choline + Creatine)/Citrate (CC/Ci) ratio and the Choline/Creatine (Cho/Cr) ratio were evaluated in each voxel with cancer or BPH confirmed by pathological results. Discriminant analysis was used to determine the power of the two ratios in differentiation between cancer and BPH.</p><p><b>RESULTS</b>The CC/Ci ratio and Cho/Cr ratio for cancer voxels were significantly higher than those in the voxels with BPH in the transitional zone (CC/Ci: 2.36 +/- 1.31 vs. 0.85 +/- 0.29, P < 0.01; Cho/Cr: 4.14 +/- 1.79 vs. 1.26 +/- 0.45, P < 0.01). As for the discriminant function with the CC/Ci ratio and the Cho/Cr ratio, the specificity, sensitivity, and accuracy were 98.6%, 85.7%, 92.9% respectively for the differentiation between cancer and BPH.</p><p><b>CONCLUSIONS</b>The prostate cancer is characterized by higher CC/Ci ratio and Cho/Cr ratio compared to BPH in the transitional zone. Both CC/Ci ratio and Cho/Cr ratio have high specificity, sensitivity, and accuracy in their discriminative power between cancer and BPH in this zonal area.</p>

Differentiation between malignant and benign ovarian tumors by magnetic resonance imaging / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To determine the magnetic resonance (MR) imaging findings of an ovarian mass which are most predictive of malignancy and assess the value of intravenous gadolinium administration in the characterization of an ovarian mass.</p><p><b>METHODS</b>Totally 74 consecutive patients with a clinically or sonographically indeterminate adnexal mass underwent MR imaging, of whom 59 had subsequent surgical resection of 70 adnexal masses. These 59 patients formed the study population. MR imaging studies were prospectively and independently reviewed by a senior and a junior radiologist. The senior radiologist also reevaluated the studies in a blind fashion after a minimum 6 months interval. The sensitivity, specificity, positive predictive value, and negative predictive value of contrast-enhanced and unenhanced MR imaging were evaluated.</p><p><b>RESULTS</b>The most predictive MR imaging findings for malignancy were presence of vegetations in a cystic lesion and presence of necrosis in a solid lesion. The odds ratio was even higher when the ancillary finding of peritoneal metastasis or ascites was present. Contrast media contributed significantly to lesion characterization. Total 70 ovarian masses were detected by contrast-enhanced MR imaging including 37 malignant ovarian masses and 33 benign ovarian masses with 87% (61/70) accuracy, 86% (32/37) sensitivity, 88% (29/33) specificity, 89% (32/36) positive predictive value, and 85% (29/34) negative predictive value, whereas 70 ovarian masses were detected by unenhanced MR imaging with 74% (52/70) accuracy, 73% (27/37) sensitivity, 76% (25/33) specificity, 77% (27/35) positive predictive value, and 71% (25/35) negative predictive value. There were significant differences in accuracy (P < 0.01), sensitivity (P < 0.01), specificity (P < 0.01) between contrast-enhanced and unenhanced MR imaging.</p><p><b>CONCLUSION</b>Contrast-enhanced MR imaging is highly accurate in detection and characterization of complex adnexal masses.</p>