Yingmao Chen

Does the Novel Integrated PET/MRI Offer the Same Diagnostic Performance as PET/CT for Oncological Indications?

Background We compared PET/MRI with PET/CT in terms of lesion detection and quantitative measurement to verify the feasibility of the novel integrated imaging modality for oncological applications. Methodology/Principal Findings In total, 285 patients referred to our PET/CT center for oncological indications voluntarily participated in this same-day PET/CT and PET/MRI comparative study. PET/CT images were acquired and reconstructed following routine protocols, and then PET/MRI was performed at a mean time interval of 28±11 min (range 15–45 min). PET/MRI covered the body trunk with a sequence combination of transverse T1WI 3D-volumetric interpolated breath-hold, T2WI turbo spin echo with fat saturation, diffusion-weighted imaging with double b values (50 and 800 s/mm2), and simultaneous PET acquisition over 45 min/5 bed positions. The maximum standardized uptake value (SUVmax) was assessed by manually drawn regions of interest over fluorodeoxyglucose-positive lesions. Among 285 cases, 57 showed no abnormalities, and 368 lesions (278 malignant, 68 benign and 22 undetermined) were detected in 228 patients. When stand-alone modalities were evaluated, PET revealed 31 and 12 lesions missed by CT and MRI, respectively, and CT and MRI revealed 38 and 61 more lesions, respectively, than PET. Compared to CT, MRI detected 40 more lesions and missed 8. In the integrated mode, PET/CT correctly detected 6 lesions misdiagnosed by PET/MRI, but was false-negative in 30 cases that were detected by PET/MRI. The overall diagnosis did not differ between integrated PET/MRI and PET/CT. SUVmax for lesions were slightly higher from PET/MRI than PET/CT but correlated well (ρ = 0.85–0.91). Conclusions/Significance The novel integrated PET/MRI performed comparatively to PET/CT in lesion detection and quantitative measurements. PET from either scanner modality offered almost the same information despite differences in hardware. Further study is needed to explore features of integrated PET/MRI not addressed in this study.

Low- and high-frequency transcutaneous electrical acupoint stimulation induces different effects on cerebral μ-opioid receptor availability in rhesus monkeys.

Although systematic studies have demonstrated that acupuncture or electroacupuncture (EA) analgesia is based on their accelerating endogenous opioid release to activate opioid receptors and that EA of different frequencies is mediated by different opioid receptors in specific areas of the central nervous system, there is little direct, real‐time evidence to confirm this in vivo. The present study was designed to investigate the effects of transcutaneous electrical acupoint stimulation (TEAS), an analogue of EA, at low and high frequencies on μ‐opioid receptor (MOR) availability in the brain of rhesus monkeys. Monkeys underwent 95‐min positron emission tomography (PET) with 11C‐carfentanil three times randomly while receiving 0, 2, or 100 Hz TEAS, respectively. Each TEAS was administered in the middle 30 min during the 95‐min PET scan, and each session of PET and TEAS was separated by at least 2 weeks. The results revealed that 2 Hz but not 100 Hz TEAS evoked a significant increase in MOR binding potential in the anterior cingulate cortex, the caudate nucleus, the putamen, the temporal lobe, the somatosensory cortex, and the amygdala compared with 0 Hz TEAS. The effect remained after the end of TEAS in the anterior cingulate cortex and the temporal lobe. The selective increase in MOR availability in multiple brain regions related to pain and sensory processes may play a role in mediating low‐frequency TEAS efficacy.

Establish New Formulas for the Calculation of Renal Depth in Both Children and Adults.

Objective This study was performed to develop a new formula to estimate the renal depth in both children and adults; then compare the new formula with previously published formulas. Methods Renal depth and total thickness (T, cm) of the body at the level of the kidneys were measured by CT in 113 children and 246 adults. Their sex, age, height (H, cm), and weight (W, kg) were recorded. Multiple stepwise linear regression analysis were conducted, using data from children and adults together. The 359 cases were divided into 2 random groups, of which, the first group was used to derive a regressive formula, and the second was used to verify the formula and compare the formula with previously published formulas in different groups. Results Multiple stepwise linear regression analysis showed that the important variable in estimating the depth of each kidney was the ratio of body weight (W, kg) to body height (H, cm) and the total thickness (T, cm) of the body at the level of the kidneys. The new formula was as follows: for right renal depth (cm) = 0.22 × T + 7.714 × W/H-0.331 (r = 0.95), and for left renal depth (cm) = 0.238 × T + 6.553 × W/H-0.618 (r = 0.95). It is better than the other four formulas in different groups, especially in children and W/H ⩽ 0.30 (in adults) groups. Conclusions We first introduced T into renal depth estimation formula and established the new formula. It has a better performance than the other four formulas in different groups. The new formula provided reliable and accurate renal depth and may contribute to improving the methods used to estimate renal function from radionuclide renography.

Standardized uptake value based evaluation of lymphoma by FDG and FLT PET/CT

Although 18F‐FDG PET/CT imaging is the conventional method for evaluating lymphoma, PET/CT imaging with radiopharmaceuticals other than FDG is being investigated. We evaluated the utility of different standardized uptake value (SUV) measurements in 18F‐FLT PET/CT scans compared with PET/CT scans performed with FDG. Two scans, each using one of the radiopharmaceuticals, were performed on each of 114 patients with histologically proven lymphoma. Maximum and mean SUV (SUVmax) and (SUVmean) of all visualized lesions, with backgrounds of mediastinal blood pool, liver, spleen and vertebra were calculated. The ratios of the SUVs of the lesions to those of each reference region were statistically analyzed. Using receiver operating characteristic curves, we analyzed the differences in uptake of the two agents in aggressive and indolent B‐cell non‐Hodgkin lymphoma. We found that the SUVmax measurements of FDG were significantly different between aggressive and indolent B‐cell non‐Hodgkin lymphoma. The receiver operating characteristic curve of SUVmax of tumour/liver for FDG studies resulted in the most area under the curve. The SUVmax of the tumour/mediastinum ratio for FLT studies resulted in the most area under the curve (0.781). There was no significant correlation between FDG and FLT uptake in most types of lymphoma we studied. Further studies of the characteristics of 18F‐FLT should employ the tumour/mediastinum SUVmax ratio for accurate uptake measurement. Copyright

Evaluation of 18F-FDG and 18F-FLT for monitoring therapeutic responses of colorectal cancer cells to radiotherapy

In order to compare the efficacy of (18)F-fluorothymidine (FLT) and (18)F-fluorodeoxyglucose (FDG) for monitoring early responses to irradiation, two human colorectal cancer (CRC) cell lines SW480 and SW620, which were derived from the primary lesions and the metastatic lymph node, underwent X-ray irradiation of 0, 10, or 20 Gy and were examined at 0, 24 and 72 h After irradiation, reduced proliferation of both SW480 and SW620 cells was observed in a dose-dependent manner (P<0.001), G0-G1 arrest was also noted in both cell types after 72 h in the 20 Gy group (P<0.001). Although increased apoptosis was observed in both cell lines after irradiation (P<0.001), a greater percentage of SW480 cells underwent apoptosis in response to irradiation than SW620 cells. Increased Hsp27 and decreased integrin β3, Ki67 and VEGFR2 expression was observed over time via immunocytochemistry and Western blot analysis (P<0.001), however, no significant changes were noted in response to irradiation. Finally, reduced uptake of (18)F-FLT by SW480 or SW620 cells was observed at 24-h post-irradiation, however, reduced (18)F-FDG uptake was only observed after 72 h. Therefore, we conclude that (18)F-FLT is a more suitable positron emission tomography (PET) tracer for monitoring early responses to irradiation in primary and metastatic lymph node CRC cells.

Suite PET/CT neuroimaging for the diagnosis of Parkinson’s disease: statistical parametric mapping analysis

Objectives The aim of this study was to investigate the topographical distribution of dopamine transporter (DAT), dopamine D2 receptor, and glucose metabolism in Parkinson’s disease (PD) using PET/computed tomography (CT) scanning and statistical parametric mapping (SPM) analysis. Participants and methods Seventy-four patients (58 PD patients and 16 normal controls) underwent DAT, D2 receptor, and glucose brain PET/CT scans using 11C-methyl-N-2-&bgr;-carbomethoxy-3-&bgr;-(4-fluorophenyl) tropane (11C-&bgr;-CFT), 11C-raclopride (11C-RAC), and fluorine-18-fluorodeoxyglucose (18F-FDG) radiotracers for the respective scans. All three PET/CT procedures were performed in each participant. The uptake patterns were analyzed using SPM software. Results Striatal DAT binding was lower in PD patients than in controls, whereas D2 receptor binding did not differ between PD patients and controls. D2 receptor binding was increased in the putamen in only the 12 drug-naive patients. Glucose uptake was also slightly lower in the cingulate gyrus of PD patients than in the controls. Conclusion Suite PET/CT scans using the ligands 11C-&bgr;-CFT, 11C-RAC, and 18F-FDG PET/CT are valuable for diagnosing PD. SPM-based analysis of static PET/CT scan data is potentially of great clinical use.

Evaluation of the accuracy of renal depth estimation formulas in horseshoe kidney

Abstract Estimation formulas are usually used to calculate renal depth when glomerular filtration rate (GFR) is measured by the Gates method. Horseshoe kidney (HSK) anatomical structure is different from the normal form of the kidney. The existing formulas are based on the normal form. It is unknown whether the existing formulas are valid in HSK patients. This study was performed to estimate the accuracy of the existing 6 renal depth estimation formulas in HSK. Renal depth and total thickness (T, cm) of the body at the level of the kidneys were measured by CT in 94 HSK patients. Their sex, age, height (H, cm), and weight (W, kg) were recorded. The existing 6 estimation formulas were used to obtain estimated renal depth. Correlation coefficients, Bland-Altman analysis, and paired t test were performed between estimated and the CT measured renal depth. Estimated renal depths were all lower than the CT measured renal depths and there was significant difference between estimated and CT measured renal depth. The CT measured renal depth and estimated renal depth derived from Ma GY formula correlated best (right: r = 0.80, P < .01; left: r = 0.77, P < .01). The renal depth derived from Tonnesen formula was significantly lower than the CT measured renal depth. The agreement between the estimated renal depth derived from Tonnesen formula and the CT measured renal depth was the worst, with the mean difference of (right: −3.11 ± 1.13 cm; left: −2.79 ± 1.07 cm). The agreement between the estimated renal depth derived from Li Q formula and Ma GY formula and the CT measured renal depth was the best, with the mean difference of right: −1.68 ± 1.09 cm; left: −1.32 ± 1.06 cm and right: −1.59 ± 1.01 cm; left: −1.59 ± 0.99 cm, respectively. But the greatest error of the difference between Li Q formula and Ma GY formula estimated depth and the CT measured depth was up to −4.83 cm, and the estimated deviation is unacceptable. All the existing formulas do not fully apply to HSK. To provide reliable and accurate estimates of renal depth, we should develop a new formula to estimate the renal depth in HSK patients.

Three-Dimensional Quantitative Evaluation of the Segmental Functional Reserve in the Cirrhotic Liver Using Multi-Modality Imaging

AbstractTo quantitatively evaluate the regional functional reserve in the cirrhotic liver and to seek related index that reflects diminished segmental liver function.A 3D system for quantitative evaluation of the liver was used to fuse technetium-99m galactosyl human serum albumin single-photon emission computed tomography and computed tomography images from 20 patients with cirrhotic liver and hepatocellular carcinoma. A set of parameters reflecting liver function including morphological liver volume, functional liver volume, functional liver density (FLD), and the drug absorption rate constant for hepatic cells (GSA-K) was calculated. Differences in FLD and GSA-K in intrahepatic segments were compared in patients with a tumor embolus (Group Y) and those without such an embolus (Group N) in the right portal vein. Differences in FLD and GSA-K in tumor-bearing (T+ group) and tumor-free (T− group) segments in patients with no tumor embolus (Group N) were also compared. Eleven living donor liver transplantation donor served as the control group.The FLD of the liver as a whole was significantly lower in patients with cirrhosis than in the control group (0.53 ± 0.13 vs 0.68 ± 0.10, P = 0.010). The FLD in segments of the right hemiliver was significantly lower than that in segments of the left hemiliver in Group Y (0.31 ± 0.21 vs 0.58 ± 0.12, P = 0.002) but not in Group N (0.60 ± 0.19 vs 0.55 ± 0.13, P = 0.294). FLD was 0.45 ± 0.17 in the T+ group and 0.60 ± 0.08 in the T− group (P = 0.008). Differences in GSA-K in intrahepatic segments were not significant. In the control group, differences in FLD and GSA-K in intrahepatic segments were not significant.The segmental liver functional reserve can be quantitatively calculated. FLD, but not GSA-K, is an index that reflects diminished regional liver function caused by portal flow obstruction or tumor compression.

Can Carrier-Mediated Delivery System Promote the Development of Antisense Imaging?

PurposeWe aimed to explore the feasibility of transfection methods for antisense imaging.ProceduresAntisense oligonucleotides (ASON) targeted to the mRNA of hTERT gene were synthesized and labeled with Technetium-99m and fluorescein isothiocyanate (FITC), respectively. Then, ASON was combined with transfection reagent Lipofectamine 2000 and XfectTM, named Lipo-ASON and Xfect-ASON, respectively. After transfection, the labeled ASON was characterized in hNPCs-G3 and hRPE cells. Reverse transcription polymerase chain reaction (RT-PCR) and Western blotting were performed to assay the hTERT mRNA and protein levels after hNPCs-G3 cells were incubated with Lipo-ASON, Xfect-ASON, and naked ASON. In addition, Lipo-ASON, Xfect-ASON, and naked ASON were injected into tumor-bearing mice, and the biodistribution in vivo was performed.ResultsThe presence of two transfection reagents significantly increased intracellular uptake of radiolabeled ASON in both cell lines compared with naked ASON (p < 0.05). However, there was no significant difference in cellular uptake rates of Lipo-ASON and Xfect-ASON between hNPCs-G3 and hRPE cells. In comparison with naked ASON, the fluorescence intensity was strongly enhanced after binding to transfection reagents. Furthermore, the levels of hTERT mRNA and protein were significantly reduced in cells treated with Lipo-ASON and Xfect-ASON (p < 0.05), but naked ASON had no significant effect on hTERT expression level. The biodistribution study indicated that tumor radioactivity uptake of radiolabeled ASON for naked ASON, Lipo-ASON, and Xfect-ASON group was low and shown no significant difference in vivo.ConclusionsLipofectamine transfection and XfectTM transfection were not effective delivery methods of ASON for antisense imaging.