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Objective:To evaluate the value of 18F-FDG PET/CT for preoperative localization of epileptogenic foci in refractory epilepsy patients with negative MRI. Methods:Clinical data (550 lobes) of 55 epilepsy patients (38 males, 17 females, age (20.0±8.1) years) with negative MRI who underwent preoperative 18F-FDG PET/CT-MRI between January 2014 and June 2020 at the First Affiliated Hospital of Jinan University were retrospectively analyzed. The sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of 18F-FDG PET/CT, video electroencephalogram (VEEG), PET/CT+ VEEG and PET/CT-VEEG for localizing epileptogenic foci were calculated using stereoelectroencephalography (SEEG) and the outcomes of at least 1 year of postoperative follow-up as reference standards. χ2 test was used to compare the efficiencies of different examination modalities for unilobar, multilobar and all patients. Results:The correct lateralization rate of epileptogenic foci was 92.6%(25/27) using PET/CT. The sensitivity, specificity, accuracy, PPV and NPV of PET/CT for localization of epileptogenic foci were 65.1%(54/83), 77.9%(364/467), 76.0%(418/550), 34.4%(54/157) and 92.6%(364/393), respectively. The sensitivities of PET/CT-VEEG for localization of epileptogenic foci in all patients and patients with multilobar epilepsy were higher than those of VEEG alone (75.9%(63/83) vs 45.8%(38/83), 68.6%(35/51) vs 31.4%(16/51); χ2 values: 15.80, 14.16, both P<0.001). The specificities of PET/CT+ VEEG for localization of epileptogenic foci in all patients and patients with unilobar epilepsy were higher than those of VEEG alone (97.6%(456/467) vs 94.6%(442/467), 97.9%(282/288) vs 94.1%(271/288); χ2 values: 5.66, 5.48; P values: 0.017, 0.019). The sensitivity of PET/CT-VEEG (PET/CT and VEEG concordance) for localization of epileptogenic foci was higher than that of PET/CT+ VEEG (PET/CT and VEEG discordance) (8/9 vs 28.4%(21/74); χ2=10.40, P=0.001), and its specificity and accuracy were higher than those of PET/CT-VEEG (PET/CT and VEEG discordance) (93.4%(57/61) vs 71.7%(291/406), 92.9%(65/70) vs 72.1%(346/480); χ2 values: 13.23, 13.96; both P<0.001). Conclusions:18F-FDG PET/CT can localize and lateralize epileptogenic foci in patients with negative MRI. The combination of 18F-FDG PET/CT and VEEG improves the sensitivity, specificity, and accuracy for epileptogenic foci detection. 18F-FDG PET/CT is more accurate in detecting epileptogenic foci when it is concordant with VEEG.
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Objective:To predict the short-term postoperative recurrence status of patients with refractory temporal lobe epilepsy (TLE) by analyzing preoperative 18F-FDG PET images and patients′ clinical characteristics based on deep residual neural network (ResNet). Methods:Retrospective analysis was conducted on preoperative 18F-FDG PET images and clinical data of 220 patients with refractory TLE (132 males and 88 females, age 23.0(20.0, 30.2) years)) in the First Affiliated Hospital of Jinan University between January 2014 and June 2020. ResNet was used to perform high-throughput feature extraction on preprocessed PET images and clinical features, and to perform a postoperative recurrence prediction task for differentiating patients with TLE. The predictive performance of ResNet model was evaluated by ROC curve analysis, and the AUC was compared with that of classical Cox proportional risk model using Delong test. Results:Based on PET images combined with clinical feature training, AUCs of the ResNet in predicting 12-, 24-, and 36-month postoperative recurrence were 0.895±0.073, 0.861±0.058 and 0.754±0.111, respectively, which were 0.717±0.093, 0.697±0.081 and 0.645±0.087 for Cox proportional hazards model respectively ( z values: -3.00, -2.98, -1.09, P values: 0.011, 0.018, 0.310). The ResNet showed best predictive effect for recurrence events within 12 months after surgery. Conclusion:The ResNet model is expected to be used in clinical practice for postoperative follow-up of patients with TLE, helping for risk stratification and individualized management of postoperative patients.
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Objective:To synthesize Gd labeled probe targeting transporter protein(TSPO) 2-(8-amino-2-(4-chlorophenyl)imidazo[1, 2-a]pyridine-3-yl)- N, N-dipropylacetamide (CB86)-diethylene triamine pentaacetic acid (DTPA), and investigate its MRI effect in rheumatoid arthritis (RA) model. Methods:CB86-DTPA was prepared by coupling a bifunctional chelating agent, and then chelated with Gd to obtain MRI targeted contrast agent CB86-DTPA-Gd. The cytotoxicity, MR relaxation rate and in vitro stability of CB86-DTPA-Gd were determined. RA model was established with Freund′s adjuvant and the biodistribution study and MRI was performed. The RA lesion and its surrounding normal tissue were used as regions of interest (ROI) to calculate the signal to noise ratio (SNR). Independent-sample t test was used to analyze the data. Results:CB86-DTPA-Gd had excellent biosafety and a good MR relaxation rate ( r1=11.05 mmol·L -1·s -1). The survival rate of RAW264.7 cells and 4T1 cells was still more than 90% at the maximum concentration (20 μmol/L) of Gd 3+. CB86-DTPA-Gd also exhibited good stability in human serum and phosphate buffer saline solution (PBS; pH=7.4). The in vivo biodistribution showed that CB86-DTPA-Gd had better inflammatory targeting efficiency, and the uptake of Gd in the inflamed site of the ankle joint was still (2.33±0.29) percent dose rate per gram of tissue (%ID/g) at 120 min after injection. MicroMRI showed that the inflammation of the right ankle joint displayed significant enhancement after the injection of CB86-DTPA-Gd and Gd-DTPA. The SNR of CB86-DTPA-Gd group was up to 23.21±1.44, and the maximum intensification time was 90 min after injection, and can be significantly inhibited by CB86-DTPA at all time points ( t values: 6.083-12.451, all P<0.05), while the Gd-DTPA group had a strengthening time of 30 min after injection with the SNR of 16.12±1.24. Conclusion:CB86-DTPA-Gd shows good macrophage targeting and good uptake in arthritic reaction sites, and is expected to be a novel MRI molecular probe for peripheral inflammation imaging.
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Objective To synthesize a novel 18 F labeled probe targeting translocator protein ( TSPO) ligand 2-( 5, 7-diethyl-2-( 4-( 2-fluoroethoxy ) phenyl ) pyrazolo [ 1, 5-a ] pyrimidin-3-yl )-N, N-diethylacet-amide (VUIIS1008), and evaluate its biodistribution and imaging in rheumatoid arthritis (RA) model. Methods The tosylate substrate was labeled with 18 F using a tosyloxy for fluorine nucleophilic aliphatic substitution to obtain 18 F-VUIIS1008. The labeling efficiency, radiochemical purity, and stability in vitro were determined. In vitro cellular uptake and competitive binding assay were performed on RAW264.7 mac-rophage cells. Biodistribution and microPET/CT imaging were investigated on RA mice established by Com-plete Freund's Adjuvant. Two-sample t test was used to analyze the data. Results 18 F-VUIIS1008 was syn-thesized with the labeling yield up to (41.00±5.00)％, the radiochemical purity>98.00％, and the specific radioactivity >1. 52 × 108 MBq/mmol. 18 F-VUIIS1008 was highly stable with the radiochemical purity >98. 00％ at 4 h after incubation in mouse serum. In vitro, it also exhibited high specific TSPO binding in RAW264.7 macrophage cells. The uptake ratio was (14.00±0.30)％ at 1 h after incubation, and decreased significantly ((4.00±0.70)％;t=12.894, P<0.05) after adding excessive unlabeled VUIIS1008. The half maximal inhibitory concentration (IC50) of 18F-VUIIS1008 binding to TSPO was 0.05 nmol/L in RAW264.7 macrophage cells. In vivo distribution results showed that the uptake of 18 F-VUIIS1008 in the left arthritic ankles reached the peak value of (1.33±0.02) percentage activity of injection dose per gram of tissue (％ID/g) at 1 h after injection. The radioactivity ratio of left ankle arthritic tissue to blood ( A/B) and to normal muscle ( A/M) was 4.40±0.22 and 1.65±0.07 respectively. MicroPET/CT imaging demonstrated that 18F-VUIIS1008 could specifically target and retained in the inflammation site. Conclusion 18 F-VUIIS1008 can be easily synthe-sized with high radiochemical purity and can clearly visualized in RA imaging with low background, suggesting its potential as a novel promising molecular probe targeting TSPO for RA PET imaging.