早期动态18F-FDG PET/CT成像在实体肿瘤评估中的应用

~(18)F-FDG PET/CT常规代谢成像反应肿瘤的葡萄糖代谢及乏氧情况,而~(18)F-FDG PET/CT早期动态成像能反映PET/CT成像早期肿瘤的灌注情况。由于肿瘤的异质性,在早期动态~(18)F-FDG PET/CT成像,即~(18)F-FDG PET/CT灌注成像中,存在独立于常规60 min~(18)F-FDG PET/CT代谢成像的SUVmax(最大标准摄取值)高摄取区。因此,在临床工作中应用~(18)F-FDG PET/CT早期动态成像,能够进一步对实体肿瘤的活性区域进行评估,能够更好评价患者预后、完善治疗方案。当前~(18)F-FDG早期动态成像已经应用在肝癌、肾癌以及膀胱癌等实体肿瘤诊断中。早期动态~(18)F-FDG PET/CT成像结合常规标准~(18)F-FDG PET/CT代谢成像,对实体肿块进行一站式成像方法,能够更好的对肿瘤进行评估。     

A Dual Tracer PET-MRI Protocol for the Quantitative Measure of Regional Brain Energy Substrates Uptake in the Rat

We present a method for comparing the uptake of the brain''s two key energy substrates: glucose and ketones (acetoacetate [AcAc] in this case) in the rat. The developed method is a small-animal positron emission tomography (PET) protocol, in which ¹¹C-AcAc and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) are injected sequentially in each animal. This dual tracer PET acquisition is possible because of the short half-life of ¹¹C (20.4 min). The rats also undergo a magnetic resonance imaging (MRI) acquisition seven days before the PET protocol. Prior to image analysis, PET and MRI images are coregistered to allow the measurement of regional cerebral uptake (cortex, hippocampus, striatum, and cerebellum). A quantitative measure of ¹¹C-AcAc and ¹⁸F-FDG brain uptake (cerebral metabolic rate; μmol/100 g/min) is determined by kinetic modeling using the image-derived input function (IDIF) method. Our new dual tracer PET protocol is robust and flexible; the two tracers used can be replaced by different radiotracers to evaluate other processes in the brain. Moreover, our protocol is applicable to the study of brain fuel supply in multiple conditions such as normal aging and neurodegenerative pathologies such as Alzheimer''s and Parkinson''s diseases.     

直径小于1 cm孤立性肺结节的18F-FDG PET/CT诊断研究进展

孤立性肺结节的鉴别诊断一直是胸部影像学的研究热点。早期且准确地鉴别肺内小结节的良恶性,对于患者治疗方案的确定以及随访情况的评估均具有重要的临床意义。~(18)F-FDG PET/CT在鉴别诊断恶性肿瘤方面具有明显优于其他传统检查的高特异性和高敏感性,其公认的恶性肿瘤的诊断阈值是最大化标准摄取值(maximum standard uptake value, SUVmax)为2.5,然而部分临床数据显示一些直径小于1 cm的恶性肺结节的SUVmax数值小于2.5。因此在早期研究中,~(18)F-FDG PET/CT在诊断直径较小的肺结节的其临床价值仍存在争议。为了尽量降低SUVmax的测量误差,提高~(18)F-FDG PET/CT诊断的准确率,衍生出了许多SUVmax辅助诊断方法以及优化的重建算法、放射性显像剂的联合应用等手段。本文将对~(18)F-FDG PET/CT鉴别诊断直径小于1 cm孤立性肺结节的研究进展进行综述。     

Intérêt diagnostique de la TEP-TDM au 18F-FDG dans le diagnostic d’endocardite infectieuse sur valve native

BackgroundNative valve endocarditis (NVE) is a rare but serious disease. The prognosis depends on the rapidity of diagnosis, and is currently based on modified Duke criteria, where echocardiography has a key role but may lack sensitivity if valves are calcified. For prosthetic valves, the European Society of Cardiology 2015 recommendations added ¹⁸F-FDG PET/CT as a major imaging criterion as well as for extension assessment. This study evaluated the diagnostic accuracy of ¹⁸F-FDG PET/CT in NVE and in extension assessment.MethodsThis retrospective study involved 59 patients suspected of NVE at Bordeaux university hospital between 2011 and 2019 and received ¹⁸F-FDG PET/CT. The final diagnosis was established according to Duke criteria after 3 months of management. Infective endocarditis (IE) was assessed in the initial phase according to the Duke criteria. All PET/CTs were blindly reviewed jointly by a junior and senior nuclear-medicine physician.ResultsIn total, 59 patients were included. At 3 months, 26 patients had definite IE, 22 had rejected IE, and 11 possible IE. Twelve patients had positive PET/CT results. The sensitivity of the modified Duke criteria in the initial phase was 77% and the specificity was 81%. When combined with ¹⁸F-FDG PET/CT, the sensitivity of the Duke criteria increased to 96% and the specificity was 81%. The sensitivity of ¹⁸F-FDG PET/CT alone was 46%. All three patients with perivalvular abscess had positive PET/CT results. Of the 22 patients with NVE definite at 3 months, fourteen (54%) had at least one septic embolism diagnosed on PET/CT.ConclusionsThe implementation of ¹⁸F-FDG PET/CT with modified Duke criteria increased the sensitivity for NVE diagnosis in the initial phase and contributed to IE extension assessment. It may contribute to making the diagnosis of a local cardiac complication.     

Radiobiological risks in terms of effective dose and organ dose from 18F-FDG whole-body PET/CT procedures

IntroductionIntegrated Positron Emission Tomography (PET) with Computerized tomography (CT) (PET/CT) are widely used to diagnose, stage and track human diseases during whole body scanning. Multi-modality imaging is an interesting area of research that aims at acquiring united morphological-functional image information for accurate diagnosing and staging of the disease. However, PET/CT procedure accompanied with high radiation dose from CT and administered radioactivity. The aim of the present study was to estimate the patients’ dose from ¹⁸F-fluorodeoxyglucose imaging (18F-FDG) hybrid PET/CT whole body scan.Materials and methodsRADAR (Radiation Dose Assessment Resource) software was used to estimate the effective dose for 156 patients (110 (70.5%)) males and 46 (39.5%) female) examined using Discovery PET/CT 710, GE Medical Systems installed at Kuwait Cancer Control Center (KCCC).ResultsThe effective dose results presented in this PET/CT study ranged from (1.56–9.94 mSv). The effective dose was calculated to be 3.88 mSv in females and 3.71 mSv in males. The overall breast (female), lung, liver, kidney and thyroid were 7.4, 7.2, 5.2, 4, 3 and 2.9, respectively.For females, the body mass index (BMI) was 28.49 kg/m² and for males it was 26.50 kg/m² which showed overweight values for both genders. Conclusions: The findings indicate that the effective dose of 18F-FDG in both male and female patients was not substantially different. The study suggested that the risk–benefit proportions of any ¹⁸F-FDG whole body PET/CT scan should be clarified and carefully weighed. Patient’s doses are lower compared with previous studies.     

Combined approach of perioperative <Superscript>18</Superscript>F-FDG PET/CT imaging and intraoperative <Superscript>18</Superscript>F-FDG handheld gamma probe detection for tumor localization and verification of complete tumor resection in breast cancer

Background

¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) has become an established method for detecting hypermetabolic sites of known and occult disease and is widely used in oncology surgical planning. Intraoperatively, it is often difficult to localize tumors and verify complete resection of tumors that have been previously detected on diagnostic PET/CT at the time of the original evaluation of the cancer patient. Therefore, we propose an innovative approach for intraoperative tumor localization and verification of complete tumor resection utilizing ¹⁸F-FDG for perioperative PET/CT imaging and intraoperative gamma probe detection.

Methods

Two breast cancer patients were evaluated. ¹⁸F-FDG was administered and PET/CT was acquired immediately prior to surgery. Intraoperatively, tumors were localized and resected with the assistance of a handheld gamma probe. Resected tumors were scanned with specimen PET/CT prior to pathologic processing. Shortly after the surgical procedure, patients were re-imaged with PET/CT utilizing the same preoperatively administered ¹⁸F-FDG dose.

Results

One patient had primary carcinoma of breast and a metastatic axillary lymph node. The second patient had a solitary metastatic liver lesion. In both cases, preoperative PET/CT verified these findings and demonstrated no additional suspicious hypermetabolic lesions. Furthermore, intraoperative gamma probe detection, specimen PET/CT, and postoperative PET/CT verified complete resection of the hypermetabolic lesions.

Conclusion

Immediate preoperative and postoperative PET/CT imaging, utilizing the same ¹⁸F-FDG injection dose, is feasible and image quality is acceptable. Such perioperative PET/CT imaging, along with intraoperative gamma probe detection and specimen PET/CT, can be used to verify complete tumor resection. This innovative approach demonstrates promise for assisting the oncologic surgeon in localizing and verifying resection of ¹⁸F-FDG positive tumors and may ultimately positively impact upon long-term patient outcomes.

     

Clinicopathologic features and outcomes following surgery for pancreatic adenosquamous carcinoma

Background

The use of diagnostic ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) imaging for the staging, restaging, and treatment monitoring of melanoma patients has become a well-recognized standard of care. It plays a key role in detecting sites of occult disease and is widely utilized in the medical and surgical planning of such patients. In the current report, we describe an innovative multimodality approach of perioperative ¹⁸F-FDG PET/CT imaging, intraoperative ¹⁸F-FDG handheld gamma probe detection, and intraoperative ultrasound for tumor localization and verification of resection of all sites of hypermetabolic tumor foci in a case of occult recurrent metastatic melanoma.

Case presentation

This report discusses a case of occult recurrent metastatic melanoma, isolated to three separate sites within the subcutaneous tissues of the left thigh region, which was not clinically apparent but was found on diagnostic restaging whole body ¹⁸F-FDG PET/CT scan utilizing an intravenous injection of 14.8 mCi ¹⁸F-FDG. Then, on the day of surgery, the patient received an intravenous injection of 12.8 mCi ¹⁸F-FDG. A multimodality approach of intraoperative handheld gamma probe detection, intraoperative ultrasound tumor localization, specimen PET/CT imaging, and postoperative PET/CT imaging was utilized for accomplishing and verifying the excision of all three sites of occult recurrent metastatic melanoma within the left thigh region.

Conclusion

This innovative multimodality approach of perioperative ¹⁸F-FDG PET/CT imaging, intraoperative ¹⁸F-FDG handheld gamma probe detection, and intraoperative ultrasound is promising combined technology for aiding in tumor localization and verification of excision and may ultimately impact positively upon long-term outcome of selected patients.     

Correlation between baseline 18F-FDG PET/CT features and pathological complete response after neoadjuvant chemotherapy in early triple negative breast cancer

Aim of the studyTo evaluate correlation between metabolic and textural parameters on baseline ¹⁸F-FDG PET/CT and pathological response after neoadjuvant chemotherapy in non-metastatic triple negative breast cancer (TNBC).MethodsAll consecutive non-metastatic TNBC women treated by neoadjuvant chemotherapy followed by breast surgery who underwent ¹⁸F-FDG PET/CT examination at diagnosis between 2012 and 2018 were retrospectively included. Metabolic parameters (SUVmax, SUVmean, SUVpeak, MTV, TLG) of the primary tumour and lymph nodes, and textural features (entropy, homogeneity, SRE, LRE, LGZE, HGZE) of the primary tumour were collected. Pathological response was defined according to Sataloff classification.ResultsSeventy-four patients were enrolled. In univariate analysis, metabolic and textural features of the primary breast lesion or metabolic parameters of regional lymph nodes were not predictive of pathological complete response after neoadjuvant chemotherapy.ConclusionMetabolic and textural features of baseline PET/CT do not seem to predict pathological response after neoadjuvant chemotherapy in non-metastatic triple negative breast cancer.     

Impact de la TEP/TDM au 18F-FDG dans la prise en charge des patients atteints de cancer thyroïdien différencié

Aim¹⁸F-FDG PET/CT by combining both metabolic and anatomical informations has proven to be an effective modality for detecting many types of cancer. Some differentiated forms of cancer like differentiated thyroid carcinoma (DTC) are less FDG avid and thus less easily detectable. Nevertheless ¹⁸F-FDG PET/CT has been proved useful in DTC especially in case of suspected recurrent disease with negative whole-body radioiodine scintigraphy (¹³¹I WBS) and elevated thyroglobulin (Tg) or thyroglobulin autoantibodies (AbTg) levels. Impact on clinical management after ¹⁸F-FDG PET/CT examinations has been analyzed in patients with suspected recurrent DTC in this retrospective study.MethodologyFifty-five ¹⁸F-FDG PET/CT were performed in 45 patients with suspected recurrent or residual disease either because of elevated Tg/AbTg levels (n = 45) or uncertain conventional imaging (n = 10) including ¹³¹I WBS, cervical echography and CT scan if necessary. ¹⁸F-FDG PET/CT results were compared with histopatology and/or clinical follow-up with evaluation of impact on clinical management.ResultsTwenty-nine exams were positive (53 %). There were 20 true-positive (TP) (14 locoregional relapses and six with distant metastases) and nine false-positive (FP) (all cervical). SUV_max median values of hypermetabolic foci were significantly higher in TP (5.1) than in FP (2.8). Overall, 20 (36 %) ¹⁸F-FDG PET/CT directly affected clinical management resulting in 13 (65 %) new surgical operations. Sensitivity, specificity, predictive positive value, predictive negative value and accuracy of ¹⁸F-FDG PET/CT were estimated for the whole group (respectively 83 %, 71 %, 69 %, 85 % and 76 %) and for two subgroups depending on Tg level (less or more than 1.2 ng/mL).Discussion and conclusion¹⁸F-FDG PET/CT is a powerful and useful tool in patients with suspected DTC recurrence or residual disease and should be systematically performed when basal Tg level is above 1.2 ng/mL. Thanks to given anatomical informations it can guide surgical re-operation.     

Comparison of 68GA-FAPI-04 PET/CT and 18F-FDG PET/CT in detection of metastatic bone disease in various cancers

ObjectiveOur aim in this retrospective study was to compare the diagnostic accuracy of ⁶⁸Ga-FAPI-04 PET/CT and ¹⁸F-FDG PET/CT in detecting bone metastases of various cancers and to evaluate the potential usefulness of ⁶⁸Ga-FAPI-04 PET/CT in detecting metastatic bone disease.Material and methodOur retrospective study included 44 patients diagnosed with bone metastases due to various cancers between January 2021 and February 2022. All patients underwent ⁶⁸Ga-FAPI-04 PET/CT and ¹⁸F-FDG PET/CT imaging within 14 days. In the semi-quantitative analysis of the skeletal system, all regions with higher uptake than background activity were considered pathological. SUVmax and Metastasis-to-background ratio (TBR) values were calculated from metastatic sites.ResultsA total of 827 bone metastases were detected in our study. The diagnostic accuracies of FAPI PET/CT and ¹⁸F-FDG PET/CT were 91.8% and 81.5%, respectively (P < 0.001). When all bone metastases were compared, the SUVmax of ⁶⁸Ga-FAPI-04 PET/CT was statistically significantly higher than that of ¹⁸F-FDG PET/CT (median 6.15 vs. 5.2; P < 0.001). When FDG and FAPI SUVmax values were compared according to metastasis types, FAPI SUVmax and TBR values in osteolytic, medullary and mixed type bone metastases were found to be statistically significantly higher than FDG (P-values: < 0.001, < 0.001, < 0.001, respectively). There was no statistically significant difference between FDG and FAPI SUVmax values in osteoblastic bone metastases (P = 0.26).ConclusionIt has been shown that ⁶⁸Ga-FAPI-04 PET/CT is superior to ¹⁸F-FDG PET/CT in detecting metastatic bone disease and may have more clinical impact on disease management.     

18F-FDG Micro PET/CT imaging to evaluate the effect of BRCA1 knockdown on MDA-MB231 breast cancer cell radiosensitivity

ObjectiveRadioresistance of tumor cells is a major factor associated with failure of radiotherapy (RT). This study aimed to investigate the effect of BRCA1 knockdown on MDA-MB231 breast cancer cell radiosensitivity.Materials and methodsShort hairpin RNA (shRNA) was used to knockdown BRCA1 gene in MDA-MB231 cells. Cell viability and proliferative capacity were assessed by CCK-8 and colony formation assays, respectively. We established xenograft models in nude mice to evaluate tumor volume and tumor weight. The mice were imaged by ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) before and after RT to evaluate changes in maximum standardized uptake value (SUV_max) and tumor SUV_max/muscle SUV_max (TMR). Changes in HIF-1α, Glut-1 and Ki-67 were analyzed and the correlation between ¹⁸F-FDG uptake and tumor biology was analyzed.ResultsCompared with the control cells, RT significantly reduced cell viability and colony formation capacity in cells with the BRCA1 gene knockdown. In vivo assays showed that there was obvious delay in the tumor growth in the shBRCA1+RT group compared with the control group. ¹⁸F-FDG Micro PET/CT indicated a reduction in glucose metabolism in the shBRCA1+RT group, with statistically significant differences in both the SUV_max and TMR. The data showed the expression of HIF-1α, Glut-1 and Ki-67 was downregulated in the shBRCA1+RT group, and both SUVmax and TMR had significant correlation with tumor biology.ConclusionThese results demonstrated that BRCA1 knockdown improves the sensitivity of MDA-MB231 breast cancer cells to RT. In addition, ¹⁸F-FDG PET/CT imaging allows non-invasive analysis of tumor biology and assessment of radiosensitivity.     

Clinical value of (18)F-FDG PET/CT in postoperative monitoring for patients with colorectal carcinoma

Objective: To evaluate the clinical value of ¹⁸F-FDG PET/CT in postoperative monitoring for patients with colorectal carcinoma. Methods: 66 postoperative patients with colorectal carcinoma underwent whole-body FDG PET/CT. The final histopathological and formal clinical follow-up findings were used as gold standard to determine the sensitivity and specificity of FDG PET/CT and enhanced CT of the same periods. Results: The sensitivity and specificity of FDG PET/CT in detecting recurrence are 96.30%, 94.87% (while enhanced CT are 70.37% and 87.18% respectively). The sensitivity and specificity in detecting metastasis are 95.35%, 82.61% (enhanced CT are 61.90%, 75.00%). SUVmax was significantly higher in malignant lesions [range 4.16–22.00, mean ± standard deviation (x ± s) 8.06 ± 4.30] than in benign ones (range1.18–6.25, x ± s 2.82 ± 1.02). Conclusion: At present, whole-body ¹⁸F-FDG PET/CT is an advanced diagnostic imaging technique in detecting loco-regional recurrence and metastasis in postoperative patients with colorectal carcinoma for its higher sensitivity and specificity.     

Dual-time-point PET/CT study protocol can improve the larynx cancer diagnosis

AimTo evaluate whether the sequential dual-time-point fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (DTP 18F-FDG PET/CT) study improves the differential diagnosis in the larynx.BackgroundIn some cases, the clinical and metabolic similarity of laryngitis and larynx cancer make differential diagnostics difficult when performing standard 18F-FDG PET/CT examinations; therefore, an additional study protocol performance seems to be of reasonable value.Materials and methods90 patients (mean age: 61 ± 11 years, range: 41–84 years): 23 women (mean age: 63 ± 10 years, range: 51–84 years) and 67 men (mean age: 61 ± 11 years, range: 41–80 years) underwent delayed 18F-FDG PET/CT examinations at 60 and 90 min post intravenous injection (p.i.) of the radiopharmaceutical 18F-FDG. We compared the metabolic activity of 90 structures divided into following groups: normal larynx (30 patients), laryngitis (30 lesions) and larynx cancer (30 tumors) with maximal and mean standardized uptake value (SUVmax, SUVmean) and the retention index (RI-SUVmax). We used the receiver operating characteristics (ROC) curve to evaluate the SUVmax cut-off values.ResultsThe SUVmax cut-off value at 60 and 90 min p.i. of 2.3 (sensitivity/specificity: 96.4%/100%) and 2.4 (94.2%/100%), respectively, distinguished normal and abnormal metabolic activity in the larynx. When laryngitis and tumors were compared, the SUVmax cut-off values obtained after initial and delayed imaging were 3.6 (87.5%/52.0%) and 6.1 (58.3%/84%), respectively. The RI-SUVmax of 1.3% (71.4%/88.1%) suggested abnormality, while RI-SUVmax of 6.6%, malignant etiology (75.0%/80.0%).ConclusionsIn this study, the sequential DTP scanning protocol improved the sensitivity and specificity of the PET/CT method in terms of differential diagnosis within the larynx.     

Can Positron Emission Tomography/Computed Tomography with the Dual Tracers Fluorine-18 Fluoroestradiol and Fluorodeoxyglucose Predict Neoadjuvant Chemotherapy Response of Breast Cancer? ----A Pilot Study

Objective

To assess the clinical value of dual tracers Positron emission tomography/computed tomography (PET/CT) ¹⁸F-fluoroestradiol (¹⁸F-FES) and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) in predicting neoadjuvant chemotherapy response (NAC) of breast cancer.

Methods

Eighteen consecutive patients with newly diagnosed, non-inflammatory, stage II and III breast cancer undergoing NAC were included. Before chemotherapy, they underwent both ¹⁸F-FES and ¹⁸F-FDG PET/CT scans. Surgery was performed after three to six cycles of chemotherapy. Tumor response was graded and divided into two groups: the responders and non-responders. We used the maximum standardized uptake value (SUVmax) to qualify each primary lesion.

Results

Pathologic analysis revealed 10 patients were responders while the other 8 patients were non-responders. There was no statistical difference of SUVmax-FDG and tumor size between these two groups (P>0.05). On the contrary, SUVmax-FES was lower in responders (1.75±0.66 versus 4.42±1.14; U=5, P=0.002); and SUVmax-FES/FDG also showed great value in predicting outcome (0.16±0.06 versus 0.54±0.22; U=5, P=0.002).

Conclusions

Our study showed ¹⁸F-FES PET/CT might be feasible to predict response of NAC. However, whether the use of dual tracers ¹⁸F-FES and ¹⁸F-FDG has complementary value should be further studied.     

Unusual spread of the follicular thyroid carcinoma,metastases to liver and pancreas

We report a multimetastatic follicular thyroid carcinoma(FTC) with match lesions between ¹⁸F-FDG PET/CT and post-treatment ¹³¹I imaging. The patient had a history of thoracic vertebra corpectomy surgery and liver tru-cut biopsy; both resulted in metastases of FTC. After total thyroidectomy surgery, the patient was referred to the ¹⁸F-FDG PET/CT to investigate other possible metastatic foci. ¹⁸F-FDG PET/CT showed increased FDG uptakes on a cervical lymph node, bones, lung, liver, and pancreas. After treatment of ¹³¹I, post-treatment iodine scintigraphy demonstrated iodine uptakes in the same areas as the ¹⁸F-FDG PET/CT scan and at the thyroid bed. All the matched lesions were concluded as a spread of the FTC. Here we describe an infrequent differentiated thyroid carcinoma case with metastases to the liver and pancreas. This case report also highlights the importance of ¹⁸F-FDG PET/CT in determining the extent of thyroid cancer.     

Does 18F-FDG Positron Emission Tomography-Computed Tomography Have a Role in Initial Staging of Hepatocellular Carcinoma?

Background and Aim

The utility of fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography-computed tomography (PET/CT) in initial staging of hepatocellular carcinoma (HCC) has yet to be fully explored. We assessed the usefulness of ¹⁸F-FDG PET/CT in initial staging of HCC.

Methods

A total of 457 consecutive patients initially diagnosed with HCC at Seoul National University Hospital between 2006 and 2012 were evaluated retrospectively to assess the impact of ¹⁸F-FDG PET/CT on staging and compliancy with Milan criteria, relative to dynamic CT of liver and chest x-ray.

Results

Seven among the 457 patients studied showed a shift in Barcelona Clinic Liver Cancer [BCLC] stage (A→C: 6 patients; B→C: 1 patient) and 5 patients who had originally met Milan criteria no longer qualified. ¹⁸F-FDG PET/CT had value in initial staging of early (stage A) or intermediate (stage B) HCC, as determined by dynamic CT of liver and BCLC or AJCC classifications, whereas BCLC stage 0 and stage C tumors were unchanged (P<0.001). ¹⁸F-FDG PET/CT disclosed additional metastases in patients with American Joint Committee on Cancer [AJCC] T2 (2.7%), T3a (5.3%), and T3b (4.8%) classifications.

Conclusions

In initial staging of HCC, ¹⁸F-FDG PET/CT provided additional information, impacting the patients with BCLC (stages A and B) and AJCC (T2 and T3) classifications. Its use might be thus appropriate for these patient subsets, especially if hepatic resection or liver transplantation is planned.     

Application of positron emission tomography to neuroimaging in sports sciences

To investigate exercise-induced regional metabolic and perfusion changes in the human brain, various methods are available, such as positron emission tomography (PET), functional magnetic resonance imaging (fMRI), near-infrared spectroscopy (NIRS) and electroencephalography (EEG). In this paper, details of methods of metabolic measurement using PET, [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) and [¹⁵O]radio-labelled water ([¹⁵O]H₂O) will be explained.Functional neuroimaging in the field of neuroscience was started in the 1970s using an autoradiography technique on experimental animals. The first human functional neuroimaging exercise study was conducted in 1987 using a rough measurement system known as ¹³³Xe inhalation. Although the data was useful, more detailed and exact functional neuroimaging, especially with respect to spatial resolution, was achieved by positron emission tomography. Early studies measured the cerebral blood flow changes during exercise. Recently, PET was made more applicable to exercise physiology and psychology by the use of the tracer [¹⁸F]FDG. This technique allowed subjects to be scanned after an exercise task is completed but still obtain data from the exercise itself, which is similar to autoradiography studies.In this report, methodological information is provided with respect to the recommended protocol design, the selection of the scanning mode, how to evaluate the cerebral glucose metabolism and how to interpret the regional brain activity using voxel-by-voxel analysis and regions of interest techniques (ROI).Considering the important role of exercise in health promotion, further efforts in this line of research should be encouraged in order to better understand health behavior. Although the number of research papers is still limited, recent work has indicated that the [¹⁸F]FDG-PET technique is a useful tool to understand brain activity during exercise.     

Intérêt de la TEP/TDM au 18F-FDG dans la neurofibromatose de type 1, expérience du centre national de référence Henri-Mondor sur 10 ans

ObjectiveMalignant peripherals nerve sheath tumours (MPNST) are one of the leading causes of death in neurofibromatosis type 1 (NF1). Given the temporal and spatial multiplicity of suspicious lesions, the histological diagnosis of certainty might require iterative and decaying surgical procedure. Our objective was to determine the threshold values of metabolic metrics determined on ¹⁸F-FDG PET/CT (SUV_max, total lesion glycolysis [TLG], total metabolic tumour volume [TMTV], tumour-to-liver [T/L] ratio and heterogeneity index [HI]) in order to distinguish at best MPNST from benign lesion (simple neurofibromas [NF] or dysplastic NF).Patients and methodsHundred and seven patients from the national reference centre of NF1 Henri-Mondor, clinically suspects of TMGN, underwent 160 ¹⁸F-FDG PET/CT over a period of 10 years, between 2005 and 2015. The hypermetabolics lesions identified on ¹⁸F-FDG PET/CT were confronted with pathological analysis or clinico-radiological and metabolic follow-up of more than 6 months.ResultsFour hundred and eight hypermetabolics lesions were identified, of which 112 were histologically confronted with 38 simple NF, 29 dysplastic NF, 39 TMGN and 6 incidentalomas. The remaining 296 hypermetabolics lesions experienced a median follow-up of 40.4 months [13.5–137 months]. The optimal cut-off values for malignant lesions, determined by ROC curves, were in order of decreasing performance: T/L ratio > 2.03 (sensitivity 96%, specificity 88%); SUVmax > 4.74 (sensitivity 93%, specificity 86%); TLG > 172 (sensitivity 84%, specificity 76%); TMTV > 53.5 (sensitivity 83%, specificity 68%); HI > 1.63 (sensitivity 84%, specificity 54%).Conclusions¹⁸F-FDG PET/CT is a powerful diagnostic and prognostic tool in the management of TMGN. Metabolic metrics allow with good sensitivity and specificity to identify lesions transformed into TMGN. The advent of PET/MRI will undoubtedly allow in the near future to reinforce the diagnostic and prognostic performances for the detection of transformations of neurofibromas in TMGN.     

Apport de la tomographie par émission de positons dans les tumeurs endocrines digestives : choix du traceur

Digestive endocrine tumors represent a heterogeneous group of neoplasm sharing common characteristics such as their high density of peptide receptors, their ability to take up amino acids and decarboxylate them into biogenic amines and their low glycolytic activity. These features are used for nuclear imaging targeting. To date, somatostatin receptor scintigraphy is considered the “gold standard” imaging procedure of well-differentiated tumors. Despite the significant contribution of SPECT/CT, the use of positron emission tomography imaging (PET) is growing rapidly. Three PET imaging modalities are currently available: 68Ga-labeled somatostatin analogs PET, 18F-dihydroxyphenylalanine PET (¹⁸F-DOPA) and 18F-deoxyglucose PET (¹⁸F-FDG). This article focuses on the current targets of molecular imaging and highlights the potential clinical applications of new targets.     

La TEP-TDM à la F-Dopa aurait-elle un rôle dans le suivi postopératoire des patients atteints de carcinome médullaire de la thyroïde ? Résultats préliminaires de l’expérience strasbourgeoise et revue de la littérature

Aim

Retrospective study to assess the value of fluorine-18 dihydroxyphenylalanine (¹⁸F-Dopa) positron emission tomography (PET)/computed tomography (CT) in the post-surgical follow-up of patients with history of medullary thyroid carcinoma (MTC) and biological suspicion of disease relapse. A review of the literature was also performed.

Patients and methods

Ten patients (23-71 years) with MTC previously treated by surgery were examined by at least one ¹⁸F-Dopa PET/CT. All patients presented with elevated serum calcitonin (130-9076 ng/l) and/or CEA (1.2-518 ng/ml) levels. 3D whole body PET/CT was performed 45 and 120 minutes after intravenous injection of 4 MBq/kg of ¹⁸F-Dopa. Scintigraphic images were visually interpreted. For quantitative analysis, maximum standardized uptake value (SUV_max) per focus was employed. PET results were compared with histological findings and/or with the results of all other imaging procedures.

Results

Seven patients (70%) had a positive ¹⁸F-Dopa PET/CT. Twenty-five focal tracer accumulations were described. Histopathological confirmation of metastatic disease was obtained in four of the seven patients with pathologic ¹⁸F-Dopa PET/CT. No scintigraphic abnormalities were evidenced in the three other patients, whose conventional morphological imaging procedures were also negatives. Delayed PET/CT examinations didn’t increase sensitivity. No correlation between ¹⁸F-Dopa PET/CT results and both serum calcitonin and CEA levels was achieved.

Conclusion

Our results are in accordance with the existing literature, showing the potential role of ¹⁸F-Dopa PET/CT in the clinical management of patients with history of MTC and biological suspicion of relapse during post-surgical follow-up. Prospective studies including larger patient series are necessary to confirm the future place of ¹⁸F-Dopa PET/CT in follow-up of MTC.