Qingwei Liu

C-11 choline PET/CT imaging for differentiating malignant from benign prostate lesions.

Purpose: To investigate the potential of C-11 choline PET/CT imaging for differentiating prostate cancer (PCa) from benign prostate hyperplasia (BPH). Materials and Methods: Forty-nine patients with prostate lesions underwent C-11 choline PET/CT imaging that was performed 5 minutes after injection of 7.4 MBq/kg (0.2 mCi/kg C-11 choline in the supine position over 2 bed positions (3 minutes per position), covering the pelvis, and the whole body (6 bed) when necessary. After attenuation correction, PET data were analyzed visually and semiquantitatively by measuring maximum standardized uptake value (SUVmax) of the prostate lesions (target) and the muscles (nontarget) and calculating their ratios (P/M). Results: Twenty-one PCa and 28 BPH lesions were proven histologically. The mean values of the SUVmax of PCa and BPH were 7.87 ± 5.74 and 4.95 ± 5.14, respectively without a significant difference between these 2 groups (t = 2.02; P > 0.05). The mean P/M of PCa and BPH were 4.21 ± 1.61 and 1.87 ± 0.98. The statistical difference of P/M between them was significant (t = 2.04; P < 0.01). Using 2.3 (P/M) as the criterion, C-11 choline PET/CT imaging showed a sensitivity of 90.48%, a specificity of 85.71%, and a negative predictive value of 92.31%. PET/CT precise localization of the hot spot in different parts of the prostate could contribute to the diagnosis. Conclusions: C-11 choline PET/CT is a valuable noninvasive imaging technology in the diagnosis of PCa. The parameter P/M could differentiate PCa from benign lesions better than SUV.

Original InvestigationDiffusion-Weighted Imaging of Prostate Cancer on 3T MR: Relationship between Apparent Diffusion Coefficient Values and Ki-67 Expression

RATIONALE AND OBJECTIVES To investigate the relationship between apparent diffusion coefficient (ADC) values and the Ki-67 staining index (Ki-67 SI), a tumor proliferation marker, in prostate cancer (PCa). MATERIALS AND METHODS Forty-three patients with PCa and thirty-six patients with benign prostatic hyperplasia (BPH) underwent diffusion-weighted (DW) imaging on 3T magnetic resonance (MR) with pelvic phased-array coil. The ADC values of PCa were calculated from two DW images (b = 0, 800 s/mm(2)). Immunohistochemical staining for Ki-67 was used to determine the Ki-67 SI of PCa and BPH. The Pearson correlation test was used to examine the relationship between ADC values and the Ki-67 SI. The ADC values of PCa with different level of Ki-67 SI were compared using an independent-sample t-test. RESULTS The mean (±standard deviation [SD]) Ki-67 SI of PCa (7.23 ± 5.29%) was higher than that of BPH (2.11 ± 1.90%) (P < .001). The mean (±SD) ADC value (10(-3) mm(2)/s) of PCa (0.850 ± 0.155) was lower than that of BPH (1.173 ± 0.245) (P < .001). The ADC values of PCa were negatively correlated with the Ki-67 SI (r = -0.459, P = .002). The mean ADC values of PCa with Ki-67 >3.5% and ≤3.5% were (0.803 ± 0.094) and (0.936 ± 0.208), respectively. The former was significantly lower than the latter (P = .031). The ADC values of PCa with Ki-67 >7.1% and ≤7.1% were (0.779 ± 0.081) and (0.906 ± 0.178), respectively. The difference was significant (P = .004). CONCLUSION The ADC values of PCa could reflect the tumor proliferative activity and the differentiated degree of PCa.

Cerebral glucose metabolism: Influence on perihematomal edema formation after intracerebral hemorrhage in cat models

Background: Most intracerebral hemorrhage (ICH) imaging studies focus on structural brain changes. Stereotactic neuroimaging techniques such as magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) are helpful in the diagnosis of ICH, monitoring the subsequent recovery and investigating its functional mechanisms. Purpose: To explore the influence of the changes in cerebral glucose metabolism on perihematomal edema formation in an experimental cat model of ICH. Material and Methods: Forty-eight cats were divided into 1 sham operation group (6 cats) and 7 ICH model groups (42 cats)”. The ICH model groups were injected with 1.0 ml autologous nonheparinized blood into their thalami using accurate stereotactic guidance apparatus. MRI and 18F-fluorodeoxyglucose (FDG) PET/CT scans were acquired at 2, 6, 12, 24, 48, 72, and 120 h following the intervention. Pearsons correlation test was used to evaluate the association between T2-weighted signal intensity and the edema volume. Students t test and q test were used to identify the times of significant temporal changes. Results: The volume of perilesional edema did not significantly increase from 2 h to 12 h after ICH, but then increased by 229.4% at 24 h, peaked (by 273.5%), and steadily decreased by 72 h. The FDG intensity in perihematomal edema tissues was markedly reduced 2 h after ICH on PET images, reached its lowest level at 12 h, and then steadily increased at 24 h and 48 h. The changes of standard absorption value (SUV) in perihematomal edema were consistent with those of FDG intensity. Conclusion: Perihematomal glucose metabolism abnormalities have a close relationship with the formation of vasogenic edema. Furthermore, abnormal glucose metabolism may impair capillary integrity and increase blood–brain barrier permeability.

Use of 11C-Choline positron emission tomography/computed tomography to investigate the mechanism of choline metabolism in lung cancer

The present study was conducted to investigate the 11C-Choline metabolic mechanism and examine the association between 11C-Choline metabolism and uptake in different pathological types of lung cancer. A total of 18 tumor specimens and corresponding normal lung tissues were collected from patients who were diagnosed with lung cancer using 11C-Choline positron emission tomography (PET)/computed tomography (CT) imaging between January 2007 and December 2008 at the Medical Imaging Center of the Provincial Hospital Affiliated to Shandong University. The diagnosis was further confirmed pathologically following surgery. Reverse transcription polymerase chain reaction and western blotting were used to investigate the expression of choline acetyltransferase (ChAT) and choline kinase α (ChoK) in lung cancer tissue and normal lung tissue. The 11C-Choline PET/CT data were analyzed visually and semiquantitatively. Compared with the expression in the normal lung tissues, the mRNA and protein expression of ChAT and ChoK increased in nine and 14 of the 18 lung tumors, respectively. A total of eight of the 18 tumors exhibited significantly increased expression, while three exhibited no expression of ChoK and ChAT. All lung cancer lesions were visualized with 11C-Choline PET/CT imaging. The phosphorylation and acetylation pathways of choline metabolism may be important in 11C-Choline uptake and metabolism in different pathological types of lung cancer.

Hiwi Promotes the Proliferation of Colorectal Cancer Cells via Upregulating Global DNA Methylation.

Hiwi is well known for its role in stem cell renewal, maintaining the resting stage, and downregulating cell cycle of stem cells via RNA silencing. And Hiwi overexpression has been recognized in several types of cancers. In the present study, we examined the Hiwi expression in colorectal cancer (CRC) specimens in both mRNA and protein levels via real-time quantitative PCR, western blot assay, and immunohistochemical staining. Then we explored the role of Hiwi in the cancer cell proliferation and in the DNA methylation in human CRC Caro-2 and HT-29 cell lines. Results demonstrated that both mRNA and protein levels of Hiwi were significantly higher in 38 CRC tissues than in 38 peritumor tissues. Moreover, the Hiwi overexpression with an adenovirus vector significantly promoted the proliferation of Caro-2 and HT-29 cells, associated with significant increase in the global DNA methylation levels. And the chemical inhibition of DNA methylation significantly restrained such proliferation promotion. In summary, we confirmed that Hiwi was overexpressed in CRC tissues and that the forced Hiwi overexpression promoted the proliferation and global DNA methylation of CRC cell lines. Our results imply for the first time that Hiwi promotes the proliferation of CRC cells via promoting global DNA methylation.

Correlations between ADC values and molecular markers of Ki-67 and HIF-1α in hepatocellular carcinoma

OBJECTIVE Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths. Cell proliferativity and hypoxia have important impact on the response to radiotherapy or chemotherapy. The purpose of this study was to investigate the association of apparent diffusion coefficient (ADC) values and the molecular markers Ki-67 and hypoxia inducible factor-α (HIF-α) in hepatocellular carcinoma (HCC). MATERIALS AND METHODS Forty-seven patients diagnosed with HCC were included in this study. All patients performed diffusion-weighted magnetic resonance imaging (DW-MRI) before any anticancer treatment. The ADC maps were automatically calculated on a Syngo workstation. The Ki-67 and HIF-1α expression were assessed by immunohistochemistry. The Pearson correlation test was used to assess the correlation between ADC values and Ki-67 and HIF-1α expression. RESULTS Ki-67 staining was clearly identified based on the brown nuclear staining in tumor cells. High Ki-67 expression was correlated with low differentiation (p=0.028). A significant correlation was observed between HIF-1α expression and maximum diameter (p=0.014). The mean ADC value was (0.983±0.21)×10(-3) mm(2)/s. The level of Ki-67 expression was correlated inversely with the ADC values (r=-0.371, p=0.01). There was a significant positive correlation between the ADC values and HIF-1α expression (r=0.389, p=0.007). CONCLUSION The ADC values were observed to correlate significantly with the molecular markers Ki-67 and HIF-1α. Our results suggest that the ADC values on DW-MRI may be used as a measure of cell proliferativity and hypoxia in hepatocellular carcinoma.

Can the Signal-to-Noise Ratio of Choline in Magnetic Resonance Spectroscopy Reflect the Aggressiveness of Endometrial Cancer?

RATIONALE AND OBJECTIVES To differentiate endometrial cancer (ECa) from benign lesions in endometrial or in submucosa (BLs-ESm), and investigate whether the signal-to-noise ratio (SNR) of choline-containing compounds (Cho) obtained from three-dimensional (1)H magnetic resonance spectroscopy (MRS) is associated with the aggressiveness of ECa. MATERIALS AND METHODS Thirty-three patients with ECa and 15 patients with BLs-ESm underwent preoperative multivoxel (1)H MRS at 3 T MR. The amplitude of Cho peak of each voxel was recorded, and the corresponding SNR of Cho peak (ChoSNR) was calculated. The maximum ChoSNR (max ChoSNR) for each lesion was identified. The max ChoSNR of ECa and BLs-ESm, as well as type I ECa and type II ECa, was compared. The relationship between max ChoSNR and pathologic characteristics of tumors, including tumor grade, stage, type, and tumor size, was analyzed. RESULTS The mean max ChoSNR (±standard deviation [SD]) was 30.93 ± 16.89 for ECa and 10.40 ± 3.07 for BLs-ESm (P < .001). The mean max ChoSNR for type II ECa (48.54 ± 21.46) was higher than that for type I ECa (26.19 ± 12.02, P = .001). There were no significant differences among different grades (P = .449). The Spearman coefficient between max ChoSNR and stage was 0.423 (P = .014); the difference existed only between Ia and III ECa (P = .048). The Pearson coefficient between ChoSNR and tumor size was 0.515 (P = .002). CONCLUSIONS The max ChoSNR obtained from MRS can differentiate ECa from BLs and type I ECa and type II ECa, but cannot differentiate between each grade ECa and each International Federation of Gynecology and Obstetrics stage ECa. However, max ChoSNR increased with the increase in International Federation of Gynecology and Obstetrics stage and size of ECa.

Combination of FDG PET/CT and Contrast-Enhanced MSCT in Detecting Lymph Node Metastasis of Esophageal Cancer

BACKGROUND Lymph node metastasis is believed to be a dependent negative prognostic factor of esophageal cancer. To explore detection methods with high sensitivity and accuracy for metastases to regional and distant lymph nodes in the clinic is of great significance. This study focused on clinical application of FDG PET/CT and contrast-enhanced multiple-slice helical computed tomography (MSCT) in lymph node staging of esophageal cancer. MATERIALS AND METHODS One hundred and fifteen cases were examined with enhanced 64-slice-MSCT scan, and FDG PET/CT imaging was conducted for neck, chest and upper abdomen within one week. The primary lesion, location and numbers of metastatic lymph nodes were observed. Surgery was performed within one week after FDG PET/CT detection. All resected lesions were confirmed histopathologically as the gold standard. Comparative analysis of the sensitivity, specificity, and accuracy based on FDG PET/CT and MSCT was conducted. RESULTS There were 946 lymph node groups resected during surgery from 115 patients, and 221 were confirmed to have metastasis pathologically. The sensitivity, specificity, accuracy of FDG PET/CT in detecting lymph node metastasis were 74.7%, 97.2% and 92.0%, while with MSCT they were 64.7%, 96.4%, and 89.0%, respectively. A significance difference was observed in sensitivity (p=0.030), but not the others (p>0.05). The accuracy of FDG PET/CT in detecting regional lymph node with or without metastasis were 91.9%, as compared to 89.4% for MSCT, while FDG PET/CT and MSCT values for detecting distant lymph node with or without metastasis were 94.4% and 94.7%. No significant difference was observed for either regional or distant lymph node metastasis. Additionally, for detecting para-esophageal lymph nodes metastasis, the sensitivity of FDG PET/CT was 72%, compared with 54.7% for MSCT (p=0.029). CONCLUSIONS FDG PET/CT is more sensitive than MSCT in detecting lymph node metastasis, especially for para-esophageal lymph nodes in esophageal cancer cases, although no significant difference was observed between FDG PET/CT and MSCT in detecting both regional and distant lymph node metastasis. However, enhanced MSCT was found to be of great value in distinguishing false negative metastatic lymph nodes from FDG PET/CT. The combination of FDG PET/CT with MSCT should improve the accuracy in lymph node metastasis staging of esophageal cancer.

Fetal Adrenal Gland in the Second Half of Gestation: Morphometrical Assessment with 3.0T Post-Mortem MRI

Background The morphometry of fetal adrenal gland is rarely described with MRI of high magnetic field. The purpose of this study is to assess the normal fetal adrenal gland length (AL), width (AW), height (AH), surface area (AS) and volume (AV) in the second half of gestation with 3.0T post-mortem MRI. Methods and Findings Fifty-two fetal specimens of 23–40 weeks gestational age (GA) were scanned by 3.0T MRI. Morphological changes and quantitative measurements of the fetal adrenal gland were analyzed. Asymmetry and sexual dimorphism were also obtained. The shape of the fetal adrenal gland did not change substantially from 23 to 40 weeks GA. The bilateral adrenal glands appeared as a ‘Y’, pyramidal or half-moon shape after reconstruction. There was a highly linear correlation between AL, AW, AH, AS, AV and GA. AW, AH, AS and AV were larger for the left adrenal gland than the right. No sexual dimorphism was found. Conclusions Our data delineated the normal fetal adrenal gland during the second half of gestation, and can serve as a useful precise reference for anatomy or in vivo fetus.

Three‑dimensional magnetic resonance volumetry of the pituitary gland is effective in detecting short stature in children

The aim of the present study was to obtain standard reference values for the pituitary gland volumes of healthy children and to analyze the potential diagnostic values of pituitary gland volumetry for growth hormone deficiency (GHD) and idiopathic short stature (ISS). The volume of the pituitary gland was measured using a thin-section three-dimensional (3D) magnetic resonance imaging (MRI) sequence of magnetization-prepared rapid gradient echo imaging with a section thickness of 1 mm. A group of 75 healthy children aged between 1 and 19 years were recruited to obtain normal volumetry values of the pituitary gland. These individuals demonstrated no evidence of abnormalities to the central nervous or endocrine systems prior to the study. An additional group of 55 children with GHD (n=32) or ISS (n=23) aged between 0 and 14 years were included in the measurement of pituitary gland volume and height. The Student’s t-test was used to evaluate the repetition test, while Pearson’s correlation coefficient and regression analyses were performed to examine the correlations between the volume and height of the pituitary glands. Pituitary gland volume and height demonstrated an increasing trend with age in the healthy children. In addition, the pituitary gland volume exhibited a growth spurt in the early teenage years (10–14 years-old), which was more prominent in females. The growth spurt was not observed for pituitary gland height. When compared with the healthy children, 65.6% of the children with GHD and 34.8% of the children with ISS had smaller pituitary gland volumes. Similarly, 37.5% of the children with GHD and 26.1% of the children with ISS had a smaller pituitary gland height compared with the healthy children. The pituitary gland volume performed significantly better compared with height with regard to the detection rate. Therefore, the results indicated that 3D MRI volumetry was useful for understanding the developmental characteristics of the pituitary gland in healthy children, and that the reference data provided by 3D MRI were effective in the diagnosis of short stature following associations with neuroimaging and clinical functional abnormalities of the pituitary gland.