Application of diffusion kurtosis tensor MR imaging in characterization of renal cell carcinomas with different pathological types and grades.

BACKGROUND: To probe the feasibility and reproducibility of diffusion kurtosis tensor imaging (DKTI) in renal cell carcinoma (RCC) and to apply DKTI in distinguishing the subtypes of RCC and the grades of clear cell RCC (CCRCC). METHODS: Thirty-eight patients with pathologically confirmed RCCs [CCRCC for 30 tumors, papillary RCC (PRCC) for 5 tumors and chromophobic RCC (CRCC) for 3 tumors] were involved in the study. Diffusion kurtosis tensor MR imaging were performed with 3 b-values (0, 500, 1000s/mm2) and 30 diffusion directions. The mean kurtosis (MK), axial kurtosis (Ka), radial kurtosis (Kr) values and mean diffusity (MD) for RCC and contralateral normal parenchyma were acquired. The inter-observer agreements of all DKTI metrics of contralateral renal cortex and medulla were evaluated using Bland-Altman plots. Statistical comparisons with DKTI metrics of 3 RCC subtypes and between low-grade (Furman grade I ~ II, 22 cases) and high-grade (Furman grade III ~ IV, 8 cases) CCRCC were performed with ANOVA test and Student t test separately. Receiver operating characteristic (ROC) curve analyses were used to compare the diagnostic efficacy of DKTI metrics for predicting nuclear grades of CCRCC. Correlations between DKTI metrics and nuclear grades were also evaluated with Spearman correlation analysis. RESULTS: Inter-observer measurements for each metric showed great reproducibility with excellent ICCs ranging from 0.81 to 0.87. There were significant differences between the DKTI metrics of RCCs and contralateral renal parenchyma, also among the subtypes of RCC. MK and Ka values of CRCC were significantly higher than those of CCRCC and PRCC. Statistical difference of the MK, Ka, Kr and MD values were also obtained between CCRCC with high- and low-grades. MK values were more effective for distinguishing between low- and high- grade CCRCC (area under the ROC curve: 0.949). A threshold value of 0.851 permitted distinction with high sensitivity (90.9%) and specificity (87.5%). CONCLUSION: Our preliminary results suggest a possible role of DKTI in differentiating CRCC from CCRCC and PRCC. MK, the principle DKTI metric might be a surrogate biomarker to predict nuclear grades of CCRCC. TRIAL REGISTRATION: ChiCTC, ChiCTR-DOD-17010833, Registered 10 March, 2017, retrospectively registered, http://www.chictr.org.cn/showproj.aspx?proj=17559 .

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.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Co5In(BTC)4[B2O4(OH)]2: the first MOF material constructed by borate polyanions and carboxylate mixed ligands.

A novel heterometallic organic-inorganic hybrid MOF material, Co5In(BTC)4[B2O4(OH)]2, has been synthesized under ionothermal conditions. Its structure is characterized as a 3D open framework constructed by the Co2.5In0.5[B2O4(OH)] cluster and the 1,3,5-benzenetricarboxylate ligand. Furthermore, its fluorescent and adsorption properties have also been studied.

Amide proton transfer magnetic resonance imaging of Alzheimer's disease at 3.0 Tesla: a preliminary study.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Detection of prostate cancer in peripheral zone: comparison of MR diffusion tensor imaging, quantitative dynamic contrast-enhanced MRI, and the two techniques combined at 3.0 T.

BACKGROUND: Previous studies have shown that the diagnostic accuracy for prostate cancer improved with diffusion tensor imaging (DTI) or quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) only. However, the efficacy of combined DTI and quantitative DCE-MRI in detecting prostate cancer at 3.0 T is still indeterminate. PURPOSE: To investigate the utility of diffusion tensor imaging (DTI), quantitative DCE-MRI, and the two techniques combined at 3.0 T in detecting prostate cancer of the peripheral zone (PZ). MATERIAL AND METHODS: DTI and DCE-MRI of 33 patients was acquired prior to prostate biopsy. Regions of interest (ROIs) were drawn according to biopsy zones which were apex, mid-gland, and base on each side of the PZ. Apparent diffusion coefficient (ADC), fractional anisotropy (FA), volume transfer constant (K(trans)), and rate constant (kep) values of cancerous sextants and non-cancerous sextants in PZ were calculated. Logistic regression models were generated for DTI, DCE-MRI, and DTI + DCE-MRI. Receiver-operating characteristic (ROC) curves were used to compare the ability of these models to differentiate cancerous sextants from non-cancerous sextants of PZ. RESULTS: There were significant differences in the ADC, FA, K(trans), and kep values between cancerous sextants and non-cancerous sextants in PZ (P < 0.0001, P < 0.0001, P < 0.0001, and P < 0.0001, respectively). The area under curve (AUC) for DTI + DCE-MRI was significantly greater than that for either DTI (0.93 vs. 0.86, P = 0.0017) or DCE-MRI (0.93 vs. 0.84, P = 0.0034) alone. CONCLUSION: The combination of DTI and quantitative DCE-MRI has better diagnostic performance in detecting prostate cancer of the PZ than either technique alone.

Diffusion tensor imaging of prostate at 3.0 Tesla.

BACKGROUND: The feasibility of diffusion tensor imaging (DTI) of prostate has been confirmed by several studies. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values of prostate with healthy or pathological changes remain controversial. PURPOSE: To investigate the efficacy of DTI at 3.0 T in diagnosing prostate cancer in the peripheral zone and to determine the normative ADC and FA values of the normal prostate. MATERIAL AND METHODS: T2-weighted imaging (T2WI) and DTI of the prostate was performed in 33 cases with diagnosis confirmed by biopsy at 3.0 T MR. ADC and FA values of cancerous and non-cancerous sextants were compared. Receiver-operating characteristic (ROC) curves were used to compare the ability of ADC, FA and the two values combined in diagnosing prostate cancer in the peripheral zone. DTI data of 20 healthy young volunteers were also acquired. ADC and FA values of the normal central gland and the peripheral zone were compared. RESULTS: ADC value (1.10 ± 0.09 × 10(-3) mm(2)/s) was lower while FA value (0.37 ± 0.05) was higher in normal central gland, compared with that in normal peripheral zone (1.63 ± 0.15 × 10(-3) mm(2)/s, 0.21 ± 0.07, respectively) (P < 0.0001, P < 0.0001, respectively). Sixteen of 33 cases were confirmed to be malignant while 17 of 33 cases were benign. All the 198 sextants were confirmed by biopsy, including 136 non-cancerous sextants and 62 cancerous sextants. There were significant differences between cancerous sextants (1.02 ± 0.16 × 10(-3) mm(2)/s, 0.38 ± 0.09) and non-cancerous sextants (1.22 ± 0.14 × 10(-3) mm(2)/s, 0.31 ± 0.06) for both ADC and FA values (P <0.0001, P <0.0001, respectively). Significant differences were noted between the AUC of DTI and FA alone (0.86 vs. 0.76, P = 0.0009), but no differences between the AUC of DTI and ADC alone (0.86 vs. 0.84, P = 0.1595). CONCLUSION: ADC and FA values of normal prostate may be compatible with the microstructural organization of prostate. Furthermore, DTI may be a potential tool in diagnosing prostate cancer in the peripheral zone.

A feasibility study of MR elastography in the diagnosis of prostate cancer at 3.0T.

BACKGROUND: MR elastography is a new imaging tool capable of non-invasively assessing the viscoelastic properties of tissues. The clinical application of MR elastography in the diagnosis of prostate cancer remains to be elucidated. PURPOSE: To investigate the feasibility of MR elastography in the diagnosis of prostate cancer at 3.0T, and to assess the elasticity and viscosity of prostate cancer and benign prostatic disease. MATERIAL AND METHODS: Eight patients (63 ± 7.25 years old) with 12 foci of prostate cancer and 10 patients (59 ± 3.25 years old) with 14 foci of prostatitis in the peripheral zone were evaluated by MRE. Ten healthy volunteers (41 ± 4.32 years old) with 18 ROIs in the peripheral zone of the prostate were also assessed with MR elastography as a control group. The results were confirmed by histopathological findings. All examinations were performed on a 3.0T Philips Achieva scanner. MRE was implemented by transmitting low-frequency longitudinal mechanical waves of 100Hz into the prostate with a transducer placed above the pubic bones. The phase images were reconstructed to acquire viscoelastic mapping. T-test was used to compare the mean elasticity and viscosity of prostate cancer and prostatitis. A comparison of prostate cancer and healthy prostate tissue in elasticity was also evaluated. The correlation of elasticity and Gleason scores between prostate cancer and prostatitis were retrospectively analyzed with Pearson Correlation. RESULTS: The mean elasticity and viscosity were significantly higher in the lesions with prostate cancer (6.55 ± 0.47 kPa, 6.56 ± 0.99 Pa.s, respectively) than in regions with prostatitis (1.99 ± 0.66 kPa, 2.13 ± 0.21 Pa.s). The difference between prostate cancer and prostatitis was statistically significant (t = 19.392, p < 0.01; t = 16.372, p < 0.01). The elasticity and viscosity of the healthy peripheral zone of prostate were 2.26 ± 0.45 kPa, 2.38 ± 0.54 Pa.s, respectively. There also was significant difference in elasticity between prostate cancer and normal peripheral zone (t = 25.136, p < 0.01). In addition, we observed a positive correlation between Gleason scores and elasticity of the prostate cancer (r = 0.913, P < 0.01) in this study. CONCLUSION: MR elastography can be used to visualize the difference in stiffness between prostate cancer and benign prostatic disease. It is a new imaging method with potential in the diagnosis of prostate cancer.

Diagnostic value of interictal diffusion-weighted imaging in evaluation of intractable temporal lobe epilepsy.

OBJECTIVE: 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). METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Functional magnetic resonance imaging and immunohistochemical study of hypothalamic function following oral glucose ingestion in rats.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Differentiation between benign prostatic hyperplasia and prostate cancer in the transitional zone evaluated by 1H magnetic resonance spectroscopic imaging.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Differentiation between malignant and benign ovarian tumors by magnetic resonance imaging.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: Contrast-enhanced MR imaging is highly accurate in detection and characterization of complex adnexal masses.