[show abstract][hide abstract] ABSTRACT: OBJECTIVES: The purpose of this study was to evaluate if positron emission tomography (PET)/magnetic resonance imaging (MRI) with just one gradient echo sequence using the body coil is diagnostically sufficient compared with a standard, low-dose non-contrast-enhanced PET/computed tomography (CT) concerning overall diagnostic accuracy, lesion detectability, size and conspicuity evaluation. METHODS AND MATERIALS: Sixty-three patients (mean age 58 years, range 19-86 years; 23 women, 40 men) referred for either staging or restaging/follow-up of various malignant tumours (malignant melanoma, lung cancer, breast cancer, Hodgkin's lymphoma, non-Hodgkin's lymphoma, CUP, gynaecology tumours, pleural mesothelioma, oesophageal cancer, colorectal cancer, stomach cancer) were prospectively included. Imaging was conducted using a tri-modality PET/CT-MR set-up (full ring, time-of-flight Discovery PET/CT 690, 3 T Discovery MR 750, both GE Healthcare, Waukesha, WI). All patients were positioned on a dedicated PET/CT- and MR-compatible examination table, allowing for patient transport from the MR system to the PET/CT without patient movement. In accordance with RECIST 1.1 criteria, measurements of the maximum lesion diameters on CT and MR images were obtained. In lymph nodes, the short axis was measured. A four-point scale was used for assessment of lesion conspicuity: 1 (>25 % of lesion borders definable), 2 (25-50 %), 3 (50-75 %) and 4 (>75 %). For each lesion the corresponding anatomical structure was noted based on anatomical information of the spatially co-registered PET/CT and PET/MRI image sections. Additionally, lesions were divided into three categories: "tumour mass", "lymph nodes" and "lesions". Differences in overall lesion detectability and conspicuity in PET/CT and PET/MRI, as well as differences in detectability based on the localisation and lesion type, were analysed by Wilcoxon signed rank test. RESULTS: A total of 126 PET-positive lesions were evaluated. Overall, no statistically significant superiority of PET/CT over PET/MRI or vice versa in terms of lesion conspicuity was found (p = 0.095; mean score CT 2.93, mean score MRI 2.75). A statistically significant superiority concerning conspicuity of PET/CT over PET/MRI was found in pulmonary lesions (p = 0.016). Additionally, a statistically significant superiority of PET/CT over PET/MRI in "lymph nodes" regarding lesion conspicuity was also found (p = 0.033). A higher mean score concerning bone lesions were found for PET/CT compared with PET/MRI; however, these differences did not achieve statistical significance. CONCLUSION: Overall, PET/MRI with body coil acquisition does not match entirely the diagnostic accuracy of standard low-dose PET/CT. Thus, it might only serve as a back-up solution in very few patients. Overall, more time needs to be invested on the MR imaging part (higher matrix, more breath-holds, additional surface coil acquired sequences) to match up with the standard low-dose PET/CT. MAIN MESSAGES : • Evaluation of whether PET/MRI with one sequence using body coil is diagnostically sufficient compared with PET/CT • PET/MRI with body coil does not match entirely the diagnostic accuracy of standard low-dose PET/CT • PET/MRI might only serve as a backup solution in patients.
[show abstract][hide abstract] ABSTRACT: OBJECTIVE: The objective of this study was to prospectively compare the detection rate, the location, and the size of pulmonary nodules in low-dose computed tomography (CT) and in magnetic resonance (MR) imaging with a 3-dimensional (3D) dual-echo gradient-echo (GRE) pulse sequence using a trimodality positron emission tomography (PET)/CT-MR setup. METHODS: Forty consecutive patients (25 men and 15 women; mean [SD] age 64  years) referred for staging of malignancy were prospectively included in this single-center, Institutional Review Board-approved study. Imaging using trimodality PET/CT-MR setup (full ring, time-of-flight PET/CT and 3-T whole-body MR imager) comprised PET, low-dose CT for anatomic referencing/attenuation correction of PET, and MR imaging with 3D dual-echo GRE pulse sequence, allowing the reconstruction of water-only (WO) and in-phase (IP) images. Two blinded and independent readers assessed all images randomly for the presence, the location, and the size of pulmonary nodules. Detection rates, defined as the proportion of screened participants with at least 1 pulmonary nodule, were compared between low-dose CT and MR imaging including both WO and IP images. RESULTS: Inter-reader agreements were high regarding the location (k = 0.93-0.98) and the size of pulmonary nodules (intraclass correlation analysis = 0.94-0.98) in CT and in MR imaging. Computed tomographic scans revealed 66 pulmonary nodules in 34 of the 40 patients (85%), whereas WO and IP images showed 56 and 58 pulmonary nodules in 33 of the 40 patients (83%), respectively. The detection rates of CT and MR imaging were similar (P's > 0.05) regarding all nodules, 18F-Fluordesoxyglucose-positive pulmonary nodules, and 18F-Fluordesoxyglucose-negative pulmonary nodules. The size of pulmonary nodules was significantly smaller on WO (P < 0.05; mean difference, 3 mm; 95% confidence interval, - 13 to 18 mm) and IP images (P < 0.001; mean difference, 4 mm; 95% confidence interval, -5 to 12 mm) compared with in CT. CONCLUSIONS: Our study indicates that a 3D Dixon-based, dual-echo GRE pulse sequence might be suitable for lung imaging in clinical whole-body PET/MR examinations. Although the detection rates were lower, there was no statistically significant difference on a patient-based evaluation concerning detection rates of pulmonary nodules compared with low-dose CT. Assessment of nodule location can be performed equally well with MR imaging.
[show abstract][hide abstract] ABSTRACT: Tri-modality PET/CT-MRI includes the transfer of the patient on a dedicated shuttle from one system into the other. Advantages of this system include a true CT-based attenuation correction, reliable PET-quantification and higher flexibility in patient throughput on both systems. Comparative studies of PET/MRI versus PET/CT are readily accomplished without repeated PET with a different PET scanner at a different time point. Additionally, there is a higher imaging flexibility based on the availability of three imaging modalities, which can be combined for the characterization of the disease. The downside is a somewhat higher radiation dose of up to 3 mSv with a low dose CT based on the CT-component, longer acquisition times and potential misalignment between the imaging components. Overall, the tri-modality PET/CT-MR system offers comparative studies using the three different imaging modalities in the same patient virtually at the same time, and may help to develop reliable attenuation algorithms at the same time.
MAGMA Magnetic Resonance Materials in Physics Biology and Medicine 10/2012; · 1.86 Impact Factor
[show abstract][hide abstract] ABSTRACT: PURPOSE: PET/MR has the potential to become a powerful tool in clinical oncological imaging. The purpose of this prospective study was to evaluate the performance of a single T1-weighted (T1w) fat-suppressed unenhanced MR pulse sequence of the abdomen in comparison with unenhanced low-dose CT images to characterize PET-positive lesions. METHODS: A total of 100 oncological patients underwent sequential whole-body (18)F-FDG PET with CT-based attenuation correction (AC), 40 mAs low-dose CT and two-point Dixon-based T1w 3D MRI of the abdomen in a trimodality PET/CT-MR system. PET-positive lesions were assessed by CT and MRI with regard to their anatomical location, conspicuity and additional relevant information for characterization. RESULTS: From among 66 patients with at least one PET-positive lesion, 147 lesions were evaluated. No significant difference between MRI and CT was found regarding anatomical lesion localization. The MR pulse sequence used performed significantly better than CT regarding conspicuity of liver lesions (p < 0.001, Wilcoxon signed ranks test), whereas no difference was noted for extrahepatic lesions. For overall lesion characterization, MRI was considered superior to CT in 40 % of lesions, equal to CT in 49 %, and inferior to CT in 11 %. CONCLUSION: Fast Dixon-based T1w MRI outperformed low-dose CT in terms of conspicuity and characterization of PET-positive liver lesions and performed similarly in extrahepatic tumour manifestations. Hence, under the assumption that the technical issue of MR AC for whole-body PET examinations is solved, in abdominal PET/MR imaging the replacement of low-dose CT by a single Dixon-based MR pulse sequence for anatomical lesion correlation appears to be valid and robust.
European Journal of Nuclear Medicine 09/2012; · 4.53 Impact Factor
[show abstract][hide abstract] ABSTRACT: The purpose of this study is to assess the successful incorporation of cages in patients after cervical or lumbar intercorporal fusion with positron-emission tomography/computed tomography (PET/CT). Twenty patients (14 female and 6 male; mean age 58 years, age range 38-73 years) with 30 cervical (n = 13) or lumbar (n = 17) intercorporal fusions were prospectively enrolled in this study. Time interval between last intercorporal intervention and PET/CT ranged from 2 to 116 months (mean 63; median 77 months). IRB approval was obtained for all patients, and written informed consent was obtained from all patients. About 30 min prior to PET/CT scanning, 97-217 MBq (mean 161 MBq) 18F-fluoride were administered intravenously. Patients were imaged in supine position on a combined PET/CT system (Discovery RX/STE, 16/64 slice CT, GE Healthcare). 3D-PET emission data were acquired for 1.5 and 2 min/bed position, respectively, and reconstructed by a fully 3D iterative algorithm (VUE Point HD) using low-dose CT data for attenuation correction. A dedicated diagnostic thin-slice CT was optionally acquired covering the fused region. Areas of increased 18F-fluoride uptake around cages were determined by one double-board certified radiologist/nuclear physician and one board certified radiologist in consensus. In 12/20 (60%) patients, increased 18F-fluoride uptake around cages was observed. Of the 30 intercorporal fusions, 15 (50%) showed increased 18F-fluoride uptake. Median time between intervention and PET/CT examination in cages with increased uptake was 37 months (2-116 months), median time between intervention and PET/CT examination in those cages without increased uptake was 91 months (19-112 months), p (Wilcoxon) = 0.01 (one-sided). 14/29 (48%) cages with a time interval > 1 year between intervention and PET/CT scan showed an increased uptake. In conclusion, PET/CT frequently shows increased 18F-fluoride uptake in cervical and lumbar cages older than 1 year (up to almost 8 years in cervical cages and 10 years in lumbar cages) possibly indicating unsuccessful fusion due to increased stress/microinstability.
European Spine Journal 12/2010; 20(4):640-8. · 2.13 Impact Factor
[show abstract][hide abstract] ABSTRACT: To evaluate the accuracy of retrospective rigid image registration and fusion between F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) of the upper abdomen.
Image fusion of PET and MRI was performed in 30 patients with suspected malignancy of the liver or pancreas. Using a commercially available image fusion tool capable of rigid manual point-based registration, PET-Images were retrospectively registered and fused by matching eight homologous points in the 3D spoiled gradient echo (GRE) MRI sequences acquired in portal venous phase and in the CT-component of PET/CT. Two separate observers (R1, R2) assessed accuracy of image registration by determining the distances in the x-, y- and z-axis as well as the absolute distance between anatomical landmarks which differed from the landmarks chosen for registration. Quality of fusion was graded using a three point grading scale (1 poorly fused; 2 satisfactory fused; 3 correctly fused) and compared to hybrid PET/CT fusion.
Mean time of registration per patient was less than 2 minutes. Objective registration assessment showed errors between 2.4-6.3 mm in x-axis: mean 3.6 mm (R1); 4.6 mm (R2), 2.3-9.3 mm in y-axis (mean 5.1 mm; 5.5 mm) and 3.3-12.0 mm in z-axis (mean 5.9 mm; 5.9 mm.) The mean error in absolute distance between points was 6.0-16.8 mm (mean 9.9 mm; 10.6 mm). In visual assessment, most fusions were graded to be satisfactory or correctly fused: R1, R2: grade 3, 11/30 (36.7%), 22/30 (73.3%); grade 2, 13/30 (43.3%), 8/30 (26.7%); grade 1, 6/30 (20%), 0/30 (0%). Fusions were mostly comparable to hybrid PET/CT fusions. All of the fusions were defined as diagnostically relevant by both observers.
Retrospective rigid image fusion of FDG-PET and MRI of the upper abdomen using the CT-component of PET/CT for registration is feasible without adaptation in image acquisition protocols and shows sub-centimeter registration errors in most cases.
[show abstract][hide abstract] ABSTRACT: The objective of this study was to evaluate the value of (18)F-FDG PET/CT and S-100B tumour marker for the detection of liver metastases from uveal melanoma in comparison to liver metastases from cutaneous melanoma.
A retrospective evaluation was conducted of 27 liver metastases in 13 patients with uveal melanoma (UM) (mean age: 56.8, range: 30-77) and 43 liver metastases in 14 patients (mean age: 57.9, range: 40-82) with cutaneous melanoma (CM) regarding size and FDG uptake by measuring the maximum standardized uptake value (SUV(max)). S-100B serum tumour markers were available in 20 patients. Cytology, histology, additional morphological imaging and follow-up served as reference standard. In nine patients liver metastases were further evaluated histologically regarding GLUT-1 and S-100 receptor expression and regarding epithelial or spindle cell growth pattern.
Of 27 liver metastases in 6 of 13 patients (46%) with UM, 16 (59%) were FDG negative, whereas all liver metastases from CM were positive. Liver metastases from UM showed significantly (p < 0.001) lower SUV(max) (mean: 3.5, range: 1.5-13.4) compared with liver metastases from CM (mean: 6.6, range: 2.3-15.3). In four of six (66.7%) patients with UM and liver metastases S-100B was normal and in two (33.3%) increased. All PET-negative liver metastases were detectable by morphological imaging (CT or MRI). S-100B was abnormal in 13 of 14 patients with liver metastases from CM. S-100B values were significantly higher (p = 0.007) in the CM patient group (mean S-100B: 10.9 microg/l, range: 0.1-115 microg/l) compared with the UM patients (mean: 0.2 microg/l, range: 0.0-0.5 microg/l). Histological work-up of the liver metastases showed no obvious difference in GLUT-1 or S-100 expression between UM and CM liver metastases. The minority (36%) of patients with UM had extrahepatic metastases and the majority (86%) of patients with CM had extrahepatic metastases, respectively. There was a close to significant trend to better survival of UM patients compared with CM patients (p = 0.06).
FDG PET/CT and serum S-100B are not sensitive enough for the detection of liver metastases from UM, whereas liver metastases from cutaneous melanoma are reliably FDG positive and lead regularly to increased S-100B tumour markers. The reason for the lower FDG uptake in UM liver metastases remains unclear. We recommend to perform combined contrast-enhanced PET/CT in order to detect FDG-negative liver metastases from UM.
European Journal of Nuclear Medicine 07/2009; 36(11):1774-82. · 4.53 Impact Factor
[show abstract][hide abstract] ABSTRACT: To evaluate the value of a dedicated interpretation of the CT images in the differential diagnosis of benign vs. malignant primary bone lesions with 18 fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG-PET/CT).
In 50 consecutive patients (21 women, 29 men, mean age 36.9, age range 11-72) with suspected primary bone neoplasm conventional radiographs and 18F-FDG-PET/CT were performed. Differentiation of benign and malignant lesions was separately performed on conventional radiographs, PET alone (PET), and PET/CT with specific evaluation of the CT part. Histology served as the standard of reference in 46 cases, clinical, and imaging follow-up in four cases.
According to the standard of reference, conventional 17 lesions were benign and 33 malignant. Sensitivity, specificity, and accuracy in assessment of malignancy was 85%, 65% and 78% for conventional radiographs, 85%, 35% and 68% for PET alone and 91%, 77% and 86% for combined PET/CT. Median SUV(max) was 3.5 for benign lesions (range 1.6-8.0) and 5.7 (range 0.8-41.7) for malignant lesions. In eight patients with bone lesions with high FDG-uptake (SUV(max) >or= 2.5) dedicated CT interpretation led to the correct diagnosis of a benign lesion (three fibrous dysplasias, two osteomyelitis, one aneurysmatic bone cyst, one fibrous cortical defect, 1 phosphaturic mesenchymal tumor). In four patients with lesions with low FDG-uptake (SUV(max) < 2.5) dedicated CT interpretation led to the correct diagnosis of a malignant lesion (three chondrosarcomas and one leiomyosarcoma). Combined PET/CT was significantly more accurate in the differentiation of benign and malignant lesions than PET alone (p = .039). There was no significant difference between PET/CT and conventional radiographs (p = .625).
Dedicated interpretation of the CT part significantly improved the performance of FDG-PET/CT in differentiation of benign and malignant primary bone lesions compared to PET alone. PET/CT more commonly differentiated benign from malignant primary bone lesions compared with conventional radiographs, but this difference was not significant.
European Journal of Nuclear Medicine 08/2008; 35(11):2000-8. · 4.53 Impact Factor
[show abstract][hide abstract] ABSTRACT: Tyrosine is a precursor of melanin synthesis and might thus present a valuable marker for melanoma. The aim of this study was to evaluate the uptake of alpha-methyl-tyrosine(AMT) in melanoma cell cultures and to assess its usefulness as a radiopharmaceutical for staging melanoma patients with whole-body scintigraphy. Melanoma (M19-cell lines) and fibroblast (negative control) cell cultures were incubated with125I-AMT and the radioactive uptake in the cell lines was measured in a gamma-counter over 24h. For in vivo studies, planar whole-body scintigraphy and single photon emission computed tomography (SPECT) of the tumour region was performed following injection of 250–350 MBq123I-AMT in six patients with known melanoma metastases. Findings were compared with results of whole-body positron emission tomography using 18F-fluorodeoxyglucose (FDG-PET) as a standard of reference. Fibroblasts showed an unchanged uptake of (mean±SD)0.56±0.09% 15min and 0.066±0.09% 24h, respectively, after incubation of 125I-AMT, whereas there was an increased uptake in melanoma cell cultures over time from 0.9±0.05% to 7.5±1.6%. In staging melanoma patients, the sensitivity of whole-body AMT-scintigraphy compared with FDG-PET was 37%(10 of 27 metastases). AMT is transported and metabolized to a high extent in melanoma cells and 123I-AMT is accumulated in melanoma metastases. Owing to its low sensitivity, however, the clinical use of whole-body AMT scintigraphy cannot be recommended.
British Journal of Dermatology 06/2008; 137(1):96 - 100. · 3.76 Impact Factor
[show abstract][hide abstract] ABSTRACT: Prevalence, optimal diagnostic approach and consequences of clinically unsuspected osteomyelitis in diabetic foot ulcers are unclear. Early diagnosis of this infection may be crucial to ensure correct management.
We conducted a prospective study in 20 diabetic patients with a chronic foot ulcer (>8 weeks) without antibiotic pretreatment and without clinical signs for osteomyelitis to assess the prevalence of clinically unsuspected osteomyelitis and to compare the value of magnetic resonance imaging (MRI), 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) and 99mTc-labelled monoclonal antigranulocyte antibody scintigraphy (99mTc-MOAB). Those with suggestive scans underwent bone biopsy for histology (n = 7).
Osteomyelitis was confirmed by biopsy in seven of the 20 clinically unsuspected foot ulcers. Presence of osteomyelitis was not related to age, ulcer size, ulcer duration, duration of diabetes or HbA1c. C-reactive protein was slightly elevated in patients with osteomyelitis (35.1 +/- 16.0 mg L(-1) vs. 12.2 +/- 2.6 mg L(-1) in patients with and without osteomyelitis respectively; P = 0.07). MRI was positive in six of the seven patients with proven osteomyelitis, whereas 18F-FDG PET and 99mTc-MOAB were positive only in (the same) two patients. Of the seven patients with osteomyelitis, five had lower limb amputation and in one patient the ulcer was persisting after 24 months of follow-up. In contrast, of the 13 patients without detectable signs of osteomyelitis on imaging modalities only two had lower limb amputation and two persisting ulcers.
Clinically unsuspected osteomyelitis is frequent in persisting foot ulcers and is a high risk factor for adverse outcome. MRI appears superior to 18F-FDG PET and 99mTc-MOAB in detecting foot ulcer-associated osteomyelitis and might be the preferred imaging modality in patients with nonhealing diabetic foot ulcers.
Journal of Internal Medicine 01/2008; 263(1):99-106. · 6.46 Impact Factor
[show abstract][hide abstract] ABSTRACT: Long-term benzimidazole therapy benefits patients with non-resectable alveolar echinococcosis (AE). Methods to assess early therapeutic efficacy are lacking. Recently, AE liver lesions were reported to exhibit increased F-18-fluorodeoxyglucose (FDG) uptake in positron emission tomography (PET). To assess the value of FDG-PET for diagnosis and follow-up of AE patients.
Twenty-six consecutive patients with newly diagnosed AE were enrolled. Baseline evaluation included CT and FDG-PET. Thirteen patients (11 women; median age 50 years, range 40-76) were resected, the remaining 13 (8 women; median age 60 years, range 39-72) had non-resectable disease, were started on benzimidazoles, and CT and FDG-PET were repeated at 6, 12 and 24 months of therapy. Twelve consecutive patients with newly diagnosed cystic echinococcosis (CE) of the liver were also subjected to baseline FDG-PET.
In 21/26 AE patients, baseline PET scans showed multifocally increased FDG uptake in the hepatic lesions' periphery, while liver lesions were FDG negative in 11/12 CE patients. Thus, sensitivity and specificity of FDG-PET for AE vs. CE were 81% and 92%, respectively. In 5 of 10 non-resectable patients with increased baseline FDG uptake, the intensity of uptake decreased (or disappeared) during benzimidazole therapy, in 3 by >or=2 grades within the initial 6 months.
FDG-PET is a sensitive and specific adjunct in the diagnosis of suspected AE and can help in differentiating AE from CE. The rapid improvement of positive PET scans with benzimidazole therapy in some patients indicates that absent FDG uptake does not necessarily reflect parasite viability.
[show abstract][hide abstract] ABSTRACT: Objectifs pédagogiques
Understand the value of CT in oncologic PET-CT.
Understand, when a combination of PET and a contrast-enhanced CT is useful in oncology.
Understand, when a low dose CT in PET-CT is sufficient in oncological patients.
Messages à retenir
Frequently PET combined with low-dose CT is adequate, particularly in tumor monitoring contrast enhancement is necessary when critical anatomic structures are potentially involved.
There is a preponderance of cystic tumorous lesions.
At initial staging no CT has been performed prior to PET-CT.
Journal De Radiologie - J RADIOL. 01/2007; 88(10):1287-1288.
[show abstract][hide abstract] ABSTRACT: Hypothyroidism is known to affect nearly every organ and organ system of the human body. The goal of the present study was to gain insight into the phosphorus metabolism and bioenergetic function of striated (calf) muscle and liver in patients with hypothyroidism before and after thyroid hormone treatment. With an ISIS (image-selected in vivo spectroscopy) magnetic resonance (MR) technique for volume selection, phosphorus-31 metabolism of the calf muscle in 10 patients and of the liver in seven patients with severe hypothyroidism was studied before and after treatment. In addition, spectra from the calf muscle and liver were obtained in 10 healthy volunteers. Relative to those from the healthy subjects, the P-31 MR spectra from patients with hypothyroidism showed a significantly diminished phosphocreatine/inorganic phosphate ratio (P < .01). After thyroid hormone substitution therapy, this ratio returned to normal values within several weeks. No statistically significant changes in the spectra of liver tissue could be detected. The results support the theory that hypothyroidism induces a hormone-dependent, fully reversible impairment of the energy metabolism of striated muscle. Changes in liver metabolism observed with biochemical methods are apparently not detectable with state-of-the-art P-31 MR spectroscopy.
Journal of Magnetic Resonance Imaging 11/2005; 2(5):527 - 532. · 2.57 Impact Factor
[show abstract][hide abstract] ABSTRACT: Over the last years, PET has developed rapidly, with the most relevant indications being in oncologic imaging. Particularly since the introduction of PET-CT it is suggested that PET will become the imaging standard in oncologic staging and therapy monitoring in the near future in many tumors. This is due to the fact that PET measures molecular events such as glucose uptake and metabolism rather than anatomical changes. Despite this, anatomical information is frequently relevant for precise staging: hence, PET in the form of PET-CT is rapidly becoming the preferred way of imaging. In 2004, there were around 8000 PET examinations performed in Switzerland. A steady further increase is expected with around 2000 to 3000 PET examinations necessary per one million inhabitants per year. Other indications for PET are in neuro-, cardio- and inflammation imaging with substantial growth potential in all fields. The next promising clinical application of PET-CT may well be integrated PET-CT of the heart for the representation of coronary anatomy combined with quantitative myocardial perfusion as "cardiac-one-stop-shop".
[show abstract][hide abstract] ABSTRACT: Gastrointestinal stromal tumours (GIST) are mesenchymal neoplasms of the gastrointestinal tract that are unresponsive to standard sarcoma chemotherapy. Imaging of GIST patients is done with structural and functional methods such as contrast-enhanced helical computed tomography (ceCT) and positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG). The aim of this study was to compare the prognostic power of PET and ceCT and to evaluate the clinical role of PET/CT imaging.
All patients with GIST undergoing PET or PET/CT examinations were prospectively included in this study, and the median overall survival, time to progression and treatment duration were documented. The prognostic significance of PET and ceCT criteria of treatment response was assessed and PET/CT was compared with PET and ceCT imaging. Data for 34 patients (19 male, 15 female, 21-76 years) undergoing PET or PET/CT for staging or restaging were analysed.
In 28 patients, PET/CT and ceCT were available after introduction of treatment with the tyrosine kinase inhibitor imatinib mesylate (Gleevec; Novartis, Basel, Switzerland). Patients without FDG uptake after the start of treatment had a better prognosis than patients with residual activity. In contrast, ceCT criteria provided insufficient prognostic power. However, more lesions were found on ceCT images than on PET images, and FDG uptake was sometimes very variable. PET/CT delineated active lesions better than did the combination of PET and ceCT imaging.
Both PET and PET/CT provide important prognostic information and have an impact on clinical decision-making in GIST patients. PET/CT precisely delineates lesions and thus allows for the correct planning of surgical interventions.
European journal of nuclear medicine and molecular imaging 03/2005; 32(2):153-62. · 5.11 Impact Factor
[show abstract][hide abstract] ABSTRACT: Objectifs pédagogiques
To understand the basic technical principles of FDG-PET imaging.
To understand combined PET/CT imaging approach.
To learn evidence based, clinical relevant indications for FDG-PET/CT.
To learn the limitations of FDG-PET/CT.
To be informed of new tracers used for PET/CT imaging (e.g. F18-Cholin).
Journal De Radiologie - J RADIOL. 01/2005; 86(10):1186-1186.
[show abstract][hide abstract] ABSTRACT: Oxidative metabolism and cerebral blood flow (CBF) are two of the most important measures in neuroimaging. However, results from concurrent imaging of the two with high spatial and temporal resolution have never been published. We used flavoprotein autofluorescence (AF) and laser speckle imaging (LSI) in the anaesthetized rat to map oxidative metabolism and CBF in response to single vibrissa stimulation. Autofluorescence responses reflecting oxidative metabolism demonstrated a fast increase with a delay of 0.1 s. The sign-reversed speckle contrast reflecting CBF started to rise with a delay of 0.6 s and reached its maximum 1.4 s after the stimulation offset. The fractional signal changes were 2.0% in AF and 9.7% in LSI. Pixelwise modelling revealed that CBF maps spread over an area up to 2.5-times larger than metabolic maps. The results provide evidence that the increase in cerebral oxidative metabolism in response to sensory stimulation is considerably faster and more localized than the CBF response. This suggests that future developments in functional imaging concentrating on the metabolic response promise an increased spatial resolution.
European Journal of Neuroscience 12/2004; 20(10):2664-70. · 3.75 Impact Factor