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Biomedical subjects

Fabrice Gutman

Publications and source records attributed to Fabrice Gutman.

17 recordsLinked to original sources
PubMed2006

PET/CT in patients with hepatocellular carcinoma using [(18)F]fluorocholine: preliminary comparison with [(18)F]FDG PET/CT.

PURPOSE: The diagnostic accuracy of [(18)F]fluorodeoxyglucose (FDG) PET is insufficient to characterise hepatocellular carcinoma (HCC) in liver masses and to diagnose all cases of recurrent HCC. HCC has been reported to take up [(11)C]acetate, but routine use of this tracer is difficult. Choline is another tracer of lipid metabolism, present in large amounts in HCC. In a proof-of-concept study, we evaluated [(18)F]fluorocholine (FCH) uptake by HCC and compared FCH PET/CT with FDG PET/CT. METHODS: Twelve patients with newly diagnosed (n=8) or recurrent HCC (n=4) were prospectively enrolled. HCC was assessed by histology in eight cases and by American Association for the Study of Liver Diseases (AASLD) criteria in four cases. All patients underwent whole-body PET/CT 10 min after injection of 4 MBq/kg FCH. Within 1 week, 9 of the 12 patients also underwent whole-body FDG PET/CT 1 h after injection of 5 MBq/kg FDG. RESULTS: The per-patient analysis showed a detection rate of 12/12 using FCH PET/CT for both newly diagnosed and recurrent HCC. The median signal to noise ratio was 1.5+/-0.38. There was a trend towards a higher FCH SUV(max) in well-differentiated HCC (15.6+/-7.9 vs 11.9+/-0.9, NS). Of the nine patients who underwent FCH and FDG PET/CT, all nine were positive with FCH whereas only five were positive with FDG. CONCLUSION: FCH provides a high detection rate for HCC, making it potentially useful in the initial evaluation of HCC or in the detection of recurrent disease. The favourable result of this proof-of-concept study opens the way to a phase III prospective study.

Carcinoma, Hepatocellular↗
PubMed2006

[FDG PET and its impact on patient's management in oncology].

FDG, a radioactive glucose analog for PET imaging, requires some precautions: it should be used only in patients with glycemia < 7mmol/L, fasting for at least 6 h but well hydrated, and after pregnancy is ruled out. FDG-PET has many indications in oncology. Its clinical utility has been documented in some circumstances, listed as routine indications in the European Principal Characteristics Summary and the French Standards, Options, and Recommendations. The European "Points to Consider" define as a principal criterion of clinical utility the impact of the imaging results on patient management. The original results presented here evaluate the clinical impact of FDG-PET among patients at Tenon Hospital by the rate of modifications in patient' management, determined with the same questionnaire as that used in two California studies of 2044 patients. Our response rate was lower than in our previous retrospective study in 2000 (34% versus 73%), probably because a prospective evaluation requires more work by the referring physician (who had to respond to two separate letters). On the other hand, the modification rate rose significantly (54% versus 46%, p<0.001), especially for colorectal cancer (58% versus 44%, p<0.02). The California studies had similar response rates (31%-48%, depending on the indication). Their modification rates were also similar, although higher for lymphoma (68%), colorectal (65%) and breast (58%) cancers.

Decision Making↗
PubMed2006

[PET and malignant cerebral tumors].

Normal biodistribution of FDG includes intense physiologic uptake in the brain, which consumes glucose. The high background therefore makes it difficult to detect the foci taking up glucose, which correspond to malignant lesions. FDG PET is nevertheless clinically useful for detecting high-grade gliomas, cerebral lymphomas and, in some cases, unexpected brain metastases in whole-body PET examinations. As an adjunct to CT and MRI, FDG-PET can make stereotactic radiosurgery more precise in targeting primary or secondary brain cancers and can differentiate necrotic fibrosis from viable cancer tissue during follow-up in cases of abnormal or equivocal MRI results. When available, methionine-(11C) PET delineates low grade gliomas accurately. Several fluorine (18F)-labeled radiopharmaceuticals have been proposed in this setting, with FET and FDOPA apparently the most effective. Four original clinical cases illustrating performances of FET and FDOPA PET in this setting are presented.

Brain Neoplasms↗
PubMed2006

[PET in head and neck cancers].

FDG PET is useful when cancer in the head or neck (except for tumors of the salivary glands, which cannot be characterized accurately) is diagnosed or suspected but not confirmed by biopsy. It can, for example, find evidence of suspicious lymph nodes in clinically N0 necks, detect foci suggestive of distant metastases or second cancers, and provide useful prognostic information. Because it can be very difficult to identify anatomical structures and landmarks on PET images in the head and neck region, PET/CT fusion is very helpful in this area. In early assessment of chemotherapy, the absence of a significant reduction in FDG uptake after one or two cycles predicts lack of efficacy and thus indicates the need to modify the regimen. Conversely, the disappearance of FDG foci indicates effective treatment and good prognosis but cannot rule out the persistence of any malignant tissue at the end of treatment, especially neoadjuvant. Diagnostic impact is probably greatest in monitoring for recurrence and restaging known recurrence: FDG PET should be performed - perhaps routinely - early enough that curative options are still open, but long enough after the end of treatment to avoid false positive results from inflammation. The strategy and timing of FDG PET during follow-up should be determined in more detail in the future, as should the role (if any) of fluorotyrosine (FET) PET in squamous cell carcinoma.

Antineoplastic Agents↗
PubMed2006

[FDG-PET in localization of cancers of unknown primary origin].

FDG-PET can be successful in localizing the primary cancer when a metastasis is discovered but no primary tumor can be identified (cancer of unknown primary, or CUP) by physical examination, laboratory testing (for tumor markers, for example) or conventional imaging. The greatest number of PET studies in CUP concern secondary lesions in cervical lymph nodes, and PET is an established clinical use (highest ranking, 1A) according to the 3rd German Consensus Conference and an "option" in the French Standards, Options, and Recommendations. Success rates range from 30% to 50% in most studies using PET; a higher rate was reported recently with PET/CT. FDG-PET should be performed sufficiently early in cases of neurological paraneoplastic syndrome, because established lesions become irreversible. Identification of the antibody present helps to specify the organ and FDG-PET can then localize the lesion; together these techniques make it possible to perform curative surgery even when the primary tumor is not visible. The success rate is somewhat lower than in cases of metastasis, around 35%. The clinical utility of PET in other paraneoplastic syndromes has not yet been sufficiently studied, but these conditions are rare. It is precisely in cases with a kind of 'orphan' indication that FDG PET should be considered, as an effective "problem solver".

Fluorodeoxyglucose F18↗
PubMed2006

[PET in thyroid cancers].

FDG PET can detect thyroid cancer in patients referred for exploration of a different cancer. Because of its lack of specificity, however, this modality is not indicated for examination of thyroid nodules: ultrasonography and fine needle biopsy with cytology allow histological diagnosis, which can be completed by iodine-123 scintigraphy when an autonomous nodule is suspected. No information is currently available about the utility of FDG PET in preoperative staging. In follow-up of patients undergoing thyroidectomy for adenocarcinoma, FDG PET is useful for detecting recurrence in cases where serum thyroglobulin levels rise and iodine-131 scintigraphy is negative: surgical resection may be appropriate. Nonetheless FDG PET should be performed more widely and earlier: the initial presence of foci positive for FDG is a major predictor of shorter survival, and most cancer lesions take up either iodine or FDG. In follow-up of medullary carcinoma, FDG PET detects residual tissue better than any other scintigraphic procedures, especially when serum levels of CEA (carcinoembryonic antigen) are rising rapidly. FDOPA PET seems to have better sensitivity than FDG-PET and may be useful in occult recurrence, as three case reports indicate.

Adenocarcinoma↗
PubMed2006

[PET in primary pulmonary or pleural cancer].

In our hospital as in many others, primary lung cancer is the most frequent indication for FDG PET. Studies have assessed the clinical utility of this imaging modality in characterizing solitary pulmonary nodules or masses, initial staging, defining tumor volume in radiotherapy and searching for recurrence of or restaging non-small cell carcinoma; studies are currently underway to evaluate its use in early assessment of chemotherapy response. Small cell lung cancer has a high FDG uptake and PET/CT can be useful for rapid staging. False negative results may be due to pure bronchioloalveolar carcinomas and endocrine tumors. FDG-PET will certainly play a more important role in the diagnosis and follow-up of pleural cancers in the future. An unexpected positive FDG PET focus should be considered as a warning, but histological proof should precede any irrevocable decisions.

Diagnosis, Differential↗
PubMed2006

Intra-individual comparison of sentinel lymph node scintigraphy on the day of injection and on the following day in breast cancer.

OBJECTIVES: To compare, intra-individually, the detection rates of sentinel node on lymphoscintigraphy performed on the day of injection (D0) and on the following day (D1) in breast carcinoma. We also compared 2-day and 1-day protocols in the two groups of patients. METHODS: The 2-day and 1-day protocols included 76 patients in group 1 and 23 patients in group 2. Patients from group 1 underwent lymphoscintigraphy twice--at 2 h (lymphoscintigraphy 1) and 18 h (lymphoscintigraphy 2) post-injection at four sites periareolar using 99mTc sulfur colloid. Patients from group 2 underwent lymphoscintigraphy only at 2 h post-injection. The detection rates and the number of sentinel nodes were compared in the two lymphoscintigraphy examinations for group 2. RESULTS: The detection rate on lymphoscintigraphy in group 1 was 92% at D0 and 96% at D1. The overall agreement between lymphoscintigraphy 1 and lymphoscintigraphy 2 was 69/76 (91%). In 2/76 women, the sentinel node disappeared at D1 on lymphoscintigraphy, but remained detectable during surgery, and in 5/76 women, the sentinel node appeared at D1 on lymphoscintigraphy. The mean number of sentinel nodes detected on lymphoscintigraphy was 2.05+/-0.14 at D0 and 1.76+/-0.11 at D1 (P=0.004) in group 2, the detection rate of the sentinel node was 20/23 (87%). CONCLUSION: Our study demonstrated that for patients undergoing the 2-day protocol for sentinel node procedure in early stage breast cancer, the optimal imaging time would be to perform lymphoscintigraphy 1 h after injection, with the possibility of imaging patients the following day in cases where lymphoscintigraphy was negative.

Breast Neoplasms↗
PubMed2006

Can fluorodihydroxyphenylalanine PET replace somatostatin receptor scintigraphy in patients with digestive endocrine tumors?

UNLABELLED: The aim of this study was to evaluate whether (18)F-fluorodihydroxyphenylalanine ((18)F-FDOPA) PET is accurate for the diagnosis and follow-up of any type of well-differentiated digestive endocrine tumor and to assess its performance compared with standard somatostatin receptor scintigraphy (SRS) using (111)In-pentetreotide. METHODS: We reviewed the results of 33 evaluable (18)F-FDOPA PET and (111)In-pentetreotide SRS examinations performed between March 2002 and September 2005 in 30 patients referred for documented well-differentiated digestive endocrine tumor. RESULTS: The sensitivity and accuracy of (18)F-FDOPA PET were significantly better for carcinoid tumors (defined according to the World Health Organization 2000 classification) (n = 19) than for noncarcinoid tumors (n = 14)-that is, 93% versus 25% for sensitivity (P < 0.01) and 89% versus 36% for accuracy (P < 0.01), respectively. In contrast, the performances of (111)In-pentetreotide SRS did not differ according to the carcinoid or noncarcinoid type of the primary endocrine tumor-that is, 81% versus 75% for sensitivity and 79% versus 71% for accuracy, respectively. In carcinoid tumors, comparison between (18)F-FDOPA PET and (111)In-pentetreotide SRS showed that (18)F-FDOPA PET more accurately evaluated the extent of disease than (111)In-pentetreotide SRS. (111)In-Pentetreotide SRS did not reveal any additional lesions in any case. Conversely, in noncarcinoid tumors, the extent of the disease was more accurately evaluated in all cases by (111)In-pentetreotide SRS than by (18)F-FDOPA PET. CONCLUSION: This preliminary study emphasizes the importance of a precise histologic characterization of well-differentiated digestive endocrine tumor to select the best radiopharmaceutical. (18)F-FDOPA PET appears to be useful in carcinoid tumors and could become the first-line scintigraphic imaging modality for these tumors, but (111)In-pentetreotide SRS appeared to be a better first-line scintigraphic imaging modality for noncarcinoid digestive tumors.

Adult↗
PubMed2005

Evaluation of a rigid registration method of lung perfusion SPECT and thoracic CT.

OBJECTIVE: The objective of our study was to evaluate a rigid registration method in lung perfusion SPECT using thoracic CT as a standard. MATERIALS AND METHODS: The reproducibility of markers selection and the robustness of the method were assessed on a torso phantom. The accuracy of registration regarding the number and location of markers and the breathing state during CT was evaluated on eight patients using 10 external markers placed around the thorax before SPECT and CT acquisitions. The accuracy of registration was assessed using the mean errors (ME) between 10 markers after registration. RESULTS: Registration using external markers on a phantom was accurate (ME, < 3 mm) when rotation was less than 40 degrees (p = 0.02). The accuracy of registration improved markedly from four to six markers for phantom (5.5-3.6 mm) and patients (11.2-9.5 mm) and then remained constant up to 10 markers. The ME was less when using markers that well encompassed the thorax for phantom and patients (p = 0.02 and p = 0.05, respectively). The use of four anatomic markers was not accurate (ME, 20 mm). CONCLUSION: The registration method is reproducible and accurate, and six external markers were required to get an ME of less than 10 mm in patients.

Aged↗
PubMed2005

Incidental colonic focal lesions detected by FDG PET/CT.

OBJECTIVE: The aim of this study was to assess the performance of FDG PET/CT for the detection of colonic lesions, especially advanced neoplasms (villous or >10-mm adenomas, carcinomas). Because of 18F FDG accumulation in adenomatous polyps, PET using FDG can detect early premalignant colorectal lesions. MATERIALS AND METHODS: FDG PET/CT studies performed for a 1-year period in 1,716 consecutive patients with various malignant diseases, except colorectal cancer, were retrospectively reviewed. PET images obtained 1 hr after FDG injection and non-contrast CT images used for attenuation correction were fused for analysis. Of 45 patients showing intense focal colonic FDG uptake, 20 patients (with 21 foci) underwent a colonoscopic investigation, and, when necessary, polyp resection. The intensity of FDG uptake was quantified using the standardized uptake value (SUV(max)). RESULTS: The FDG colonic foci were associated with 18 colonoscopic abnormalities in 15 patients, with no colonic abnormality detected in five patients (false-positive [FP] results). Histopathologic findings revealed advanced neoplasms in 13 patients (13 villous adenomas and three carcinomas) and two cases of hyperplastic polyps. A difference in the mean SUV(max) was found between FP and true-positive colonic FDG foci but was not statistically significant (p = 0.14). CONCLUSION: Presence of a focal colonic FDG uptake incidental finding on a PET/CT scan justifies a colonoscopy to detect (pre-)malignant lesions. The fusion of PET and CT images allows an accurate localization of the lesions. PET/CT is a useful tool to differentiate pathologic from physiologic FDG uptake.

Adenoma↗
PubMed2005

[FDG (18 fluorodeoxyglucose) positron emission tomography and breast cancer].

Positron emission tomography (PET) is a metabolic radionuclide imaging method in which a tracer labeled with a positron emitter is detected with a dedicated system. 18F-fluorodeoxyglucose (FDG) accumulates in tumor cells because of their increased glycolytic activity, and is thus widely used as a tracer in oncology. This increased metabolic activity precedes morphologic modifications, making FDG-PET a very useful tool for detecting and staging cancer. It can also be used to characterize morphologic changes, differentiating not only between benign and malignant lesions, but also between viable tumor cells and areas of necrosis and/or fibrosis induced by treatments. Being a whole-body examination, it allows malignancies to be staged in a single procedure. Systems combining PET and CT (computed tomography) offer improved performance, providing both metabolic and anatomical data. This technique appears to be useful for initial breast cancer staging, especially of locally advanced forms and suspected recurrences (increase of isolated tumor marker). Early studies of PET evaluation of responses to hormonal and/or cytotoxic therapies have also given very promising results. However, this technique does not seem sufficiently sensitive to be included in the initial screening or diagnosis of primary tumors, owing to its limited resolution (about 5 mm) and its restricted availability. This approach is poorly sensitive when used for axillary assessment, but offers good specificity.

Breast Neoplasms↗
PubMed2003

Optimisation of the OS-EM algorithm and comparison with FBP for image reconstruction on a dual-head camera: a phantom and a clinical 18F-FDG study.

Iterative reconstruction algorithms, such as the ordered subsets expectation maximisation (OS-EM), are a promising alternative to filtered backprojection (FBP). The aims of this study were first to optimise the OS-EM algorithm in terms of iteration number and to study the usefulness of post-filtering, and second to compare OS-EM and FBP for image reconstruction on a fluorine-18 fluorodeoxyglucose ((18)F-FDG) dual-head camera (DHC). These two goals were addressed using phantom acquisitions. The performances of these algorithms were also studied in patient acquisitions performed on a DHC and a PET on the same day. Phantom experiments were performed on a DHC using a Jaszczak phantom containing six spheres filled with (18)F-FDG, two background levels (0.95, 6.80 kBq/ml) and three object contrasts (5.9, 3.7, 2.7). The reconstruction algorithms were FBP with a Gaussian filter (FWHM 0.5-2 pixel width) and OS-EM using 8-128 equivalent iterations (equivalent to the ML-EM algorithm) with and without Gaussian post-filtering [OS-EM (iterations, pixel width)]. Contrast recovery coefficient (CRC) and noise characteristics were assessed. Twenty-two patients (21 male, one female; age 55+/-15 years) with lung cancer underwent, on the same day, PET (1 h post injection of 37 MBq/kg (18)F-FDG) and DHC acquisitions (3 h post injection). DHC data were reconstructed using six methods: FBP (1), OS-EM (16), (40), (40,1), (64) and (64,1). These sets were evaluated by two observers and compared to PET reconstructed with OS-EM (16). The number of detected lesions and the visual quality were assessed. A marked improvement in CRC was observed with OS-EM as compared with FBP when more than 24 iterations were used. The CRC increased markedly from 8 to 40 iterations and then reached a plateau. The noise was stable until 40 iterations and then increased. The best compromise was obtained for OS-EM (32) and OS-EM (40,1). For the patient study, OS-EM provided images of better visual quality, but with no significant difference in detection sensitivity. OS-EM was superior to FBP in terms of contrast recovery and noise level. The optimal compromise between contrast recovery and noise was obtained for OS-EM (32) and (40,1) on the phantom study. The clinical study showed that OS-EM yielded images of better visual quality but with no improvement in terms of detection of lung cancer.

Algorithms↗