Jean-Noël Talbot

Early 18F-FDG PET for Prediction of Prognosis in Patients with Diffuse Large B-Cell Lymphoma: SUV-Based Assessment Versus Visual Analysis

The purpose of this study was to assess the prognostic value of early 18F-FDG PET using standardized uptake value (SUV) compared with visual analysis in patients with diffuse large B-cell lymphoma (DLBCL). Methods: Ninety-two patients with newly diagnosed DLBCL underwent 18F-FDG PET prospectively before and after 2 cycles of chemotherapy (at midtherapy). Maximum SUV (SUVmax) and mean SUV (SUVmean) normalized to body weight and body surface area, as well as tumor-to-normal ratios, were computed on the most intense uptake areas. The SUVs, tumor-to-normal ratios, and their changes over time were compared with visual analysis for predicting event-free survival (EFS) and overall survival, using receiver-operating-characteristic (ROC) analysis. Survival curves were estimated with Kaplan–Meier analysis and compared using the log-rank test. Results: With visual analysis, the accuracy of early PET to predict EFS was 65.2%. The 2-y estimate for EFS was 51% (95% confidence interval [CI], 34%–68%) in the PET-positive group compared with 79% (95% CI, 68%–90%) in the PET-negative group (P = 0.009). An optimal cutoff value of 65.7% SUVmax reduction from baseline to midtherapy obtained from ROC analysis yielded an accuracy of 76.1% to predict EFS. The 2-y estimate for EFS was 21% (95% CI, 0%–42%) in patients with SUVmax reduction ≤ 65.7% compared with 79% (95% CI, 69%–88%) in those with reduction > 65.7% (P < 0.0001). Fourteen patients considered as positive on visual analysis could have been reclassified as good responders. Conclusion: SUV-based assessment of therapeutic response during first-line chemotherapy improves the prognostic value of early 18F-FDG PET compared with visual analysis in DLBCL.

CT and 18F-deoxyglucose (FDG) image fusion for optimization of conformal radiotherapy of lung cancers

PURPOSE To validate a computed tomography (CT) and (18)F-deoxyglucose (FDG) image fusion procedure and to evaluate its usefulness to facilitate target definition and treatment planning in three-dimensional conformal radiation therapy (3D-CRT) for non-small-cell lung cancer. METHODS AND MATERIALS Twelve patients were assessed by CT and FDG-coincidence mode dual-head gamma camera (CDET) before radiotherapy. The patients were placed in a similar position during CT and FDG-CDET. Matching was achieved by minimizing the cost function by 3D translation and rotation between four landmarks drawn on the patients skin. Virtual simulation was performed from image fusion and estimated dose-volume histograms (DVH) were calculated. RESULTS Quantitative analysis indicated that the matching error was < 5 mm. Fusion of anatomic and metabolic data corrected staging of lymph nodes (N) for 4 patients and staging of metastases for 1 patient. In these 5 patients, DVH revealed that the lung volume irradiated at 20 Gy (Vl(20)) was decreased by an average of 22.8%, and tumor volume irradiated at the 95% isodose (V(95)) was increased by 22% and 8% for 2 patients, respectively, and was decreased by an average of 59% for 3 patients after fusion. No difference in terms of Vl(20) and V(95) was observed for the other 7 patients. CONCLUSION We have validated CT and FDG-CDET lung image fusion to facilitate determination of lung cancer volumes, which improved the accuracy of 3D-CRT.

Detection of Hepatocellular Carcinoma with PET/CT: A Prospective Comparison of 18F-Fluorocholine and 18F-FDG in Patients with Cirrhosis or Chronic Liver Disease

This prospective study aimed to compare the diagnostic performance of 18F-fluorocholine and 18F-FDG for detecting and staging hepatocellular carcinoma (HCC) in patients with chronic liver disease and suspected liver nodules. Methods: Whole-body PET/CT was performed in a random order at 10 min after injection of 4 MBq of 18F-fluorocholine per kilogram and at 1 h after injection of 5 MBq of 18F-FDG per kilogram. PET/CT results were read in a masked manner by 2 specialists, and diagnostic performance was assessed from the results of consensus masked reading. Those focal lesions appearing with increased or decreased activity, compared with background, on 18F-fluorocholine PET/CT were considered positive for malignancy. The standard of truth was determined on a per-site basis using data from a histologic examination and a follow-up period of more than 6 mo; on a per-patient basis, the Barcelona criteria were also accepted as a proof of HCC in 5 patients. Results: Eighty-one patients were recruited; standard of truth was determined in 59 cases. HCC was diagnosed in 34 patients. Therefore, sensitivity was 88% for 18F-fluorocholine and 68% for 18F-FDG (P = 0.07), and in 70 sites, sensitivity was 84% for 18F-fluorocholine, significantly better than the 67% for 18F-FDG (P = 0.01). Of the 11 patients with well-differentiated HCC, 6 had a positive result with 18F-fluorocholine alone, whereas 18F-FDG was never positive alone; corresponding site-based sensitivity was 94% for 18F-fluorocholine and 59% for 18F-FDG (P = 0.001). The detection rate of 18 sites corresponding to other malignancies was 78% for 18F-fluorocholine and 89% for 18F-FDG. In nonmalignant sites, 18F-fluorocholine appeared less specific than 18F-FDG (62% vs. 91% P < 0.01) because of uptake by focal nodular hyperplasia. Conclusion: 18F-fluorocholine was significantly more sensitive than 18F-FDG at detecting HCC, in particular in well-differentiated forms. In contrast, 18F-FDG appeared somewhat more sensitive at detecting other malignancies and was negative in focal nodular hyperplasia. Thus 18F-fluorocholine appears to be a useful PET/CT tracer for the detection and surveillance of HCC; however, performing PET/CT with both radiopharmaceuticals seems to be the best option.

Early detection of recurrence by 18FDG-PET in the follow-up of patients with colorectal cancer

We assessed the potential benefits of including systematic 18fluorodeoxyglucose positron emission tomography (FDG-PET) for detecting tumour recurrence in a prospective randomised trial. Patients (N=130) who had undergone curative therapy were randomised to undergo either conventional (Con) or FDG-PET procedures during follow-up. The two groups were matched at baseline. Recurrence was confirmed histologically. ‘Intention-to-treat’ analysis revealed a recurrence in 46 patients (25 in the FDG-PET group, and 21 in the Con group; P=0.50), whereas per protocol analysis revealed a recurrence in 44 out of 125 patients (23 and 21, respectively; P=0.60). In another three cases, PET revealed unexpected tumours (one gastric GIST, two primary pulmonary cancers). Three false-positive cases of FDG-PET led to no beneficial procedures (two laparoscopies and one liver MRI that were normal). We failed to identify peritoneal carcinomatosis in two of the patients undergoing FDG-PET. The overall time in detecting a recurrence from the baseline was not significantly different in the two groups. However, recurrences were detected after a shorter time (12.1 vs 15.4 months; P=0.01) in the PET group, in which recurrences were also more frequently (10 vs two patients) cured by surgery (R0). Regular FDG-PET monitoring in the follow up of colorectal cancer patients may permit the earlier detection of recurrence, and influence therapy strategies.

Evaluation of Fluorodeoxyglucose Positron Emission Tomography in the Detection of Axillary Lymph Node Metastases in Patients With Early-Stage Breast Cancer

AbstractBackground: The aim of this study was to assess the capacity of positron emission tomography (PET) with fluorodeoxyglucose (FDG) to determine axillary lymph node status in patients with breast cancer undergoing sentinel node (SN) biopsy. Methods: Thirty-two patients with breast cancer and clinically negative axillary nodes were recruited. All patients underwent FDG-PET before SN biopsy. After SN biopsy, all patients underwent complete axillary lymph node (ALN) dissection. Results: The SNs were identified in all patients. Fourteen patients (43.8%) had metastatic SNs (macrometastatic in seven, micrometastatic in six, and isolated tumor cells in one). The false-negative rate of SN biopsy was 6.6% (1 in 15). FDG-PET identified lymph node metastases in 3 of the 14 patients with positive SNs. The overall sensitivity, specificity, and positive and negative predictive values of FDG-PET in the diagnosis of axillary metastasis were 20%, 100%, 100%, and 58.6%, respectively. No false-positive findings were obtained with FDG-PET. Conclusions: This study demonstrates the limitations of FDG-PET in the detection of ALN metastases in patients with early breast cancer. In contrast, FDG-PET seems to be a specific method for staging the axilla in breast cancer. SN biopsy can be avoided in patients with positive FDG-PET, in whom complete ALN dissection should be the primary procedure.

[18F]FDG in recurrent breast cancer: diagnostic performances, clinical impact and relevance of induced changes in management

Prognosis and management of patients with recurrent breast cancer depend on the spread of the disease. The aim of this study was to evaluate the performance of fluorine-18 fluorodeoxyglucose gamma camera positron emission tomography (FDG-GPET) in detecting breast cancer recurrence, its clinical impact and the relevance of induced changes in management. Patients (n=134) with suspicion of recurrence either clinically or on conventional imaging (suspected recurrence: SR) or with an isolated increase in tumour marker levels (occult recurrence: OR) underwent FDG-GPET on a coincidence gamma camera. The reference standard for evaluation of accuracy, either histology (n=26) or follow-up for 1 year (n=49), was available in 75 (56%) patients. A questionnaire was sent to the referring clinician to evaluate the impact of FDG on management. Responses were obtained for 75 patients. Information regarding both approaches was available for 46 patients (46/134=34%). At the patient level, the sensitivity of FDG-GPET was 84%, significantly higher than the 63% sensitivity for conventional modalities, and the specificity was 78% versus 61%. The values for FDG-GPET were 81% and 86% respectively in the SR group and 90% and 73% respectively in the OR group, without any significant difference between these settings. The rate of change in management was 44% overall, 43% in the SR group and 45% in the OR group. Within the two groups, intermodality (major) changes were more frequent than intramodality (minor) changes. In the 46 patients for whom both approaches were available, 93% of management modifications were relevant (validated by biopsy or clinical follow-up). The results of this retrospective study show that FDG-GPET has an important role to play in patient management by confirming and evaluating the extent of recurrence or by localising occult recurrence

Is 18F-Fluorocholine-Positron Emission Tomography/Computerized Tomography a New Imaging Tool for Detecting Hyperfunctioning Parathyroid Glands in Primary or Secondary Hyperparathyroidism?

CONTEXT Preoperative ultrasonography and scintigraphy using (99m)Tc-sestamibi are commonly used to localize abnormal parathyroid glands. In cases of discrepant results between scintigraphy and ultrasonography, it is important to rely on another diagnostic imaging modality. (18)F-fluorodeoxyglucose (FDG) and (11)C-methionine positron emission tomography (PET) have been studied, but are imperfect to detect abnormal parathyroid glands. Recently, first cases of abnormal parathyroid glands taking-up radiolabelled choline were discovered incidentally in men referred to (11)C-choline or (18)F-fluorocholine (FCH)-PET/CT for prostate cancer. We checked if FCH uptake was a general feature of adenomatous or hyperplastic parathyroid glands. METHODS FCH-PET/CT was performed in 12 patients with primary (n = 8) or secondary hyperparathyroidism (1 dialyzed, 3 grafted) and with discordant or equivocal results on preoperative ultrasonography (US) and/or (123)I/(99m)Tc-sestamibi dual-phase scintigraphy. The results of the FCH-PET/CT were evaluated, with surgical exploration and histopathologic examination as the standard of truth. RESULTS On a per-patient level, the detection rate of FCH-PET/CT (at least one FCH focus corresponding to an abnormal parathyroid gland in a given patient) was 11/12 = 92%. FCH-PET/CT detected 18 foci interpreted as parathyroid glands and correctly localized 17 abnormal parathyroid glands (7 adenomas and 10 hyperplasias). On a per-lesion level, FCH-PET/CT results were 17 TP, 2 false negative ie, a lesion-based sensitivity of 89%, and 1 false positive. CONCLUSION As the main result of this pilot study, we show that in patients with hyperparathyroidism and with discordant or equivocal results on scintigraphy or on ultrasonography, adenomatous or hyperplastic parathyroid glands can be localized by FCH-PET/CT with good accuracy. Furthermore, FCH-PET/CT can solve discrepant results between preoperative ultrasonography and scintigraphy and has thus a potential as a functional imaging modality in the detection of abnormal parathyroid glands. Our preliminary results are encouraging and prompt us to further evaluate FCH-PET/CT as a functional imaging agent in patients with biochemical hyperparathyroidism.

A Pilot Comparison of 18F-fluorocholine PET/CT, Ultrasonography and 123I/99mTc-sestaMIBI Dual-Phase Dual-Isotope Scintigraphy in the Preoperative Localization of Hyperfunctioning Parathyroid Glands in Primary or Secondary Hyperparathyroidism: Influence of Thyroid Anomalies

AbstractWe compared 18F-fluorocholine hybrid positron emission tomography/X-ray computed tomography (FCH-PET/CT) with ultrasonography (US) and scintigraphy in patients with hyperparathyroidism and discordant, or equivocal results of US and 123I/99mTc-sesta-methoxyisobutylisonitrile (sestaMIBI) dual-phase parathyroid scintigraphy. FCH-PET/CT was performed in 17 patients with primary (n = 11) lithium induced (n = 1) or secondary hyperparathyroidism (1 dialyzed, 4 renal-transplanted).The reference standard was based on results of surgical exploration and histopathological examination. The results of imaging modalities were evaluated, on site and by masked reading, on per-patient and per-lesion bases.In a first approach, equivocal images/foci were considered as negative. On a per-patient level, the sensitivity was for US 38%, for scintigraphy 69% by open and 94% by masked reading, and for FCH-PET/CT 88% by open and 94% by masked reading. On a per-lesion level, sensitivity was for US 42%, for scintigraphy 58% by open and 83% by masked reading, and for FCH-PET/CT 88% by open and 96% by masked reading. One ectopic adenoma was missed by the 3 imaging modalities. Considering equivocal images/foci as positive increased the accuracy of the open reading of scintigraphy or of FCH-PET/CT, but not of US. FCH-PET/CT was significantly superior to US in all approaches, whereas it was more sensitive than scintigraphy only for open reading considering equivocal images/foci as negative (P = 0.04). FCH uptake was more intense in adenomas than in hyperplastic parathyroid glands. Thyroid lesions were suspected in 9 patients. They may induce false-positive results as in one case of oncocytic thyroid adenoma, or false-negative results as in one case of intrathyroidal parathyroid adenoma. Thyroid cancer (4 cases) can be visualized with FCH as with 99mTc-sestaMIBI, but the intensity of uptake was moderate, similar to that of parathyroid hyperplasia.This pilot study confirmed that FCH-PET/CT is an adequate imaging tool in patients with primary or secondary hyperparathyroidism, since both adenomas and hyperplastic parathyroid glands can be detected. The sensitivity of FCH-PET/CT was better than that of US and was not inferior to that of dual-phase dual-isotope 123I/99mTc-scintigraphy. Further studies should evaluate whether FCH could replace 99mTc-sestaMIBI as the functional agent for parathyroid imaging, but US would still be useful to identify thyroid lesions.

Peritoneal tuberculosis revealed by carcinomatosis on CT scan and uptake at FDG‐PET

Peritoneal tuberculosis is uncommon in industrialised countries. The resurgence of this insidious and non-specific form of ‘carcinomatosis’ is promoted by immune suppression (especially Human Immunodeficiency Virus), migration, and poverty. There are no pathognomonic clinical, radiologic or laboratory tests. In its peritoneal form, tuberculosis cannot be differentiated from ovarian cancer except by histopathology.

Detection of bronchioloalveolar cancer by means of PET/CT and 18F-fluorocholine, and comparison with 18F-fluorodeoxyglucose.

AimBronchioloalveolar (BAC) cancer is a source of false-negative 18F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) results. A few studies reported better diagnostic performances with PET tracers of lipid metabolism, 11C-choline, or 11C-acetate, for the detection of well-differentiated adenocarcinoma or BAC. 18F-fluorocholine (FCH) is a lipid analogue for PET imaging, with advantages in terms of logistics and image resolution. We carried out this prospective pilot study to evaluate whether FCH PET/CT could detect lung cancer with a BAC component and could be more sensitive than FDG in this aim. MethodsFifteen patients with a lung nodule or lesion suspected for BAC on CT and/or with a history of BAC had PET/CT 60–90 min after 5 MBq FDG/kg body mass and, on a separate day, 10–20 min after 4 MBq FCH/kg body mass. The standard of truth was histology and a 6-month follow-up. ResultsNine patients (12 lesions) presented BAC or adenocarcinoma with BAC features, two patients presented adenocarcinoma without BAC features (five lesions) and four patients presented benign lesions (15 non-malignant sites). For both FCH and FDG, patient-based sensitivity was 78% for detecting cancer with a BAC component and 82% for detecting malignancy. Site-based sensitivity for detecting malignancy was 76 and 75% for detecting cancer with BAC features, for both radiopharmaceuticals. Specificity was similar for FCH and FDG (site-based 93 vs. 81%, NS). In these early-stage cancers, only one adrenal metastasis was observed that took up FCH and FDG. ConclusionIn this population of patients with ground-glass opacities selected on CT suggestive of BAC or with a history of BAC and a recent lung anomaly on CT, FCH detected all malignant lesions with at least a 2.0 cm short axis. However, FDG had similar performance.