Preoperative assessment of cervical lymph nodes in head and neck cancer with fluorine-18 fluorodeoxyglucose using a dual-head coincidence camera: a pilot study

The aim of this study was to investigate whether in patients with head and neck cancer, staging is possible with fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) using a dual-head positron emission tomography (PET) camera. Twenty patients (ten men, ten women; mean age: 60 years) were studied using 185 MBq (5 mCi) ¹⁸F-FDG. Two of these patients who were suspected of having recurrence in the neck were restaged 19 and 12 months, respectively, after the resection of the primary tumour. The images were visually analyzed and the results were correlated with computed tomography (CT) (n = 18), ultrasonography (n = 17) and pathological findings. With respect to the primary tumour, FDG dual-head PET and CT revealed a sensitivity of 100% and 59%, respectively (P<0.001). In seven patients lymph node metastases were found in the neck specimen. Two of them had bilateral metastases. FDG dual-head PET correctly identified all nine pathological neck sides whereas CT and ultrasonography depicted eight of nine and seven of eight pathological sides, respectively. In three patients, false-positive FDG uptake was seen, which was due to a preceding biopsy in two cases. The sensitivity of FDG dual-head PET, CT and ultrasonography in the identification of pathological neck sides was 100%, 89% and 87%, respectively, and the specificity was 90%, 93% and 50%, respectively. With knowledge of the preceding biopsies, the specificity of FDG dual-head PET would have been 97%. The smallest lymph node metastasis detected by FDG dual-head PET that was missed by CT had a diameter of 0.6 cm. Measurement of ¹⁸F-FDG with a dual-head PET camera is very sensitive in the detection of primary head and neck cancers and accurate in the preoperative assessment of lymph node metastases. The results justify a prospective study on the identification of metastases in patients with head and neck cancer. In addition, it is justified to start a study on the detection of unknown primary tumours in patients with cervical metastases. Received 19 October and in revised form 18 December 1998     

Cardiac fluorine-18 fluorodeoxyglucose imaging using a dual-head gamma camera with coincidence detection: a clinical pilot study

Dual-headed gamma cameras with coincidence detection (MCD) are increasingly used for imaging of positron-emitting tracers, such as fluorine-18 fluorodeoxyglucose (FDG). In this study, we examined differences between FDG MCD and FDG positron emission tomography (PET) as the gold standard to determine whether FDG MCD could be used for assessment of myocardial viability in daily practice. Nineteen patients with a previous myocardial infarction (17 men; mean left ventricular ejection fraction 44%+/-13%) underwent FDG MCD, FDG PET, resting echocardiography and technetium-99m tetrofosmin gated single-photon emission tomography (SPET). At the 50% threshold value for FDG PET, the area under the receiver operating characteristic curve for FDG MCD was 0.77+/-0.03. In 107 dyssynergic segments on echocardiography and 151 segments with hypoperfusion on 99mTc-tetrofosmin SPET, the specificity of FDG MCD for the detection of myocardial viability was 72% and 76% respectively, with a sensitivity of 69% and 72% respectively. Regional analysis showed a significantly lower agreement of FDG MCD and FDG PET in the inferior and septal regions (58% for dyssynergic segments and 65% for segments with hypoperfusion), as compared with the other regions (85% for dyssynergic regions, P<0.05, and 86% for segments with hypoperfusion, P<0.05). Five patients (26%), who all had a body mass index > or =25% kg/m2, showed more than 25% disagreement between FDG MCD and FDG PET. Because of the moderate overall agreement with FDG PET, the low sensitivity in akinetic or dyskinetic regions and the low agreement in the inferior and septal regions, further studies and implementations of technical developments are needed before FDG MCD can be introduced into clinical practice for the assessment of myocardial viability.     

Cardiac fluorine-18 fluorodeoxyglucose imaging using a dual-head gamma camera with coincidence detection: a clinical pilot study

Dual-headed gamma cameras with coincidence detection (MCD) are increasingly used for imaging of positron-emitting tracers, such as fluorine-18 fluorodeoxyglucose (FDG). In this study, we examined differences between FDG MCD and FDG positron emission tomography (PET) as the gold standard to determine whether FDG MCD could be used for assessment of myocardial viability in daily practice. Nineteen patients with a previous myocardial infarction (17 men; mean left ventricular ejection fraction 44%±13%) underwent FDG MCD, FDG PET, resting echocardiography and technetium-99m tetrofosmin gated single-photon emission tomography (SPET). At the 50% threshold value for FDG PET, the area under the receiver operating characteristic curve for FDG MCD was 0.77±0.03. In 107 dyssynergic segments on echocardiography and 151 segments with hypoperfusion on ^99mTc-tetrofosmin SPET, the specificity of FDG MCD for the detection of myocardial viability was 72% and 76% respectively, with a sensitivity of 69% and 72% respectively. Regional analysis showed a significantly lower agreement of FDG MCD and FDG PET in the inferior and septal regions (58% for dyssynergic segments and 65% for segments with hypoperfusion), as compared with the other regions (85% for dyssynergic regions, P<0.05, and 86% for segments with hypoperfusion, P<0.05). Five patients (26%), who all had a body mass index ≥25% kg/m², showed more than 25% disagreement between FDG MCD and FDG PET. Because of the moderate overall agreement with FDG PET, the low sensitivity in akinetic or dyskinetic regions and the low agreement in the inferior and septal regions, further studies and implementations of technical developments are needed before FDG MCD can be introduced into clinical practice for the assessment of myocardial viability. Received 4 December 1999 and in revised form 5 February 2000     

The detection of local recurrent head and neck cancer with fluorine-18 fluorodeoxyglucose dual-head positron emission tomography.

Primary tumors of the larynx and hypopharynx are preferably treated with high-dose radiation therapy. In these patients, it may be difficult to distinguish recurrent disease from post-treatment reactions. The aim of the present study was to assess the value of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) in the detection of local relapses of laryngeal or hypopharyngeal carcinoma after radiotherapy using a dual-head PET camera. Forty-eight patients (43 male, 5 female; mean age +/-SD, 61+/-9.5 years) with suspected recurrent laryngeal or hypopharyngeal cancer were prospectively studied. The mean interval between initial treatment and suspicion of recurrent disease was 14.6 months (range: 3-100 months). FDG dual-head PET was followed by endoscopy with or without biopsy under general anaesthesia within a period of 2 months in all patients. The mean period of follow-up after FDG dual-head PET was 13.7 months. In 19 out of 31 patients with focally increased uptake, tumour recurrence (mean diameter: 2.4 cm; range 0.4-6.5 cm) was found at initial endoscopy. In five patients recurrence was found during follow-up with a mean interval of 6.6 months. Seven patients had a false-positive study due to benign lesions or swallowing artefacts. In none of the patients with a normal PET study was tumour recurrence found during follow-up. The sensitivity and specificity of FDG dual-head PET were 100% and 71%, respectively. It is concluded that FDG dual-head PET is highly sensitive for the detection of local recurrence of laryngeal and hypopharyngeal carcinoma after radiotherapy. Some lesions were detected with a mean interval of 6.6 months before histological confirmation. In patients suspected of having recurrent laryngeal or hypopharyngeal cancer in whom FDG-PET is negative, endoscopy may be omitted for at least 6 months and possibly for up to 1 year.     

Fluorine-18 fluorodeoxyglucose imaging using dual-head coincidence positron emission tomography without attenuation correction in patients with head and neck cancer.

PURPOSE: An accurate, preoperative assessment of tumor extent and lymph node involvement is necessary to plan and tailor therapy for patients with head and neck cancer. Metabolic imaging with fluorine-18 fluorodeoxy-glucose (FDG) is a good method to detect primary tumors in the head and neck and to assess the involvement of lymph nodes, but it is not widely available because of the high cost of positron emission tomography (PET). Recently, an alternative method for using FDG was developed: coincidence detection PET (CoDe PET) using a gamma camera. The aim of this study was to evaluate the clinical utility of FDG CoDe PET using a gamma camera in patients with head and neck cancer. MATERIALS AND METHODS: Thirty FDG CoDe PET studies without attenuation correction were performed in seven patients before therapy and in 19 patients after therapy (ages: 25-79 years, mean, 50 +/- 13 years; 18 men, 8 women) with various head and neck cancers. All patients had fasted for 6 to 12 hours and were injected with 111 to 370 MBq F-18 FDG 1 hour before imaging. Visually detectable focal FDG uptake in the primary tumor site or in the neck was considered positive except for physiologic uptake. The FDG CoDe PET studies were correlated with MRI. The gold standard for the presence of disease was the combination of repeated MRIs, endoscopic examination, and 3 months of follow-up clinical evaluation. RESULTS: FDG CoDe PET had a detection rate that was comparable to that of MRI in the pretherapy group. However, in the posttherapy group, FDG CoDe PET could differentiate residual tumor or tumor recurrence from radiation change more accurately than could MRI. However, it had a less accurate detection rate for cervical node metastases because of asymmetric neck muscle uptake. CONCLUSIONS: FDG CoDe PET is a sensitive and cost-effective method to detect primary tumor and lymph node involvement in primary head and neck cancers. It is also useful in differentiating residual tumor or tumor recurrence from posttherapy changes in patients with head and neck tumors.     

Imaging of lung cancer with fluorine-18 fluorodeoxyglucose: comparison of a dual-head gamma camera in coincidence mode with a full-ring positron emission tomography system

Dual-head gamma cameras operated in coincidence mode are a new approach for tumour imaging using fluorine-18 fluorodeoxyglucose (FDG). The aim of this study was to assess the diagnostic accuracy of such a camera system in comparison with a full-ring positron emission tomography (PET) system in patients with lung cancer. Twenty-seven patients (1 female, 26 males, age 62±9 years) with lung cancer or indeterminate pulmonary nodules were studied on the same day with a full-ring PET scanner (Siemens ECAT EXACT) and a coincidence gamma camera system (ADAC Vertex MCD). Sixty minutes after injection of 185–370 MBq FDG, a scan of the chest was performed with the full-ring system. Approximately 2 h p.i., the coincidence camera study was performed. Coincidence gamma camera (CGC) and PET images with (PETac) and without attenuation correction (PETnac) were analysed independently by two blinded observers. In addition, FDG uptake in primary tumours and involved lymph nodes was quantified relative to normal contralateral lung (T/L ratios). All primary tumours were histologically proven. The lymph node status was histologically determined in 23 patients. In four patients, no lymph node sampling was performed because of extensive disease or concurrent illnesses. In the 27 patients, 25 primary lung cancers and two metastatic lesions were histologically diagnosed. The number of coincidences per centimetre axial field of view was 3.33±0.93×10⁵ for the CGC and 1.09±0.36×10⁶ for the dedicated PET system. All primary tumours (size: 4.6±2.6 cm) were correctly identified in the CGC and dedicated PET studies. T/L ratios were 4.7±2.5 for CGC and 6.9±2.8 for PETnac (P <0.001). Histopathological evaluation revealed lymph node metastases in 11 of 88 sampled lymph node stations (size: 2.3±1.0 cm). All lymph node metastases were identified in the PETac studies, while PETnac detected 10/11 and CGC 8/11. For positive lymph nodes that were visible in CGC and PETnac studies, T/L ratios were 3.7±2.3 for CGC and 6.6±3.1 for PETnac (P=0.02). The diameters of false-negative lymph nodes in the CGC studies were 0.75, 1.5 and 2 cm. False-positive FDG uptake in lymph nodes was found in two patients with all three imaging methods. For all lesions combined, T/L ratios in CGC relative to PETnac studies decreased significantly with decreasing lesion size (r=0.62; P<0.001). In conclusion, compared with a full-ring PET system the sensitivity of CGC imaging for detection of lung cancer is limited by a lower image contrast which deteriorates with decreasing lesion size. Nevertheless, the ability of CGC imaging to detect pulmonary lesions with a diameter of at least 2 cm appears to be similar to that of a full-ring system. Both systems provide a similar specificity for the evaluation of lymph node involvement. Received 29 August and in revised form 7 December 1998     

Imaging of lung cancer with fluorine-18 fluorodeoxyglucose: comparison of a dual-head gamma camera in coincidence mode with a full-ring positron emission tomography system

Dual-head gamma cameras operated in coincidence mode are a new approach for tumour imaging using fluorine-18 fluorodeoxyglucose (FDG). The aim of this study was to assess the diagnostic accuracy of such a camera system in comparison with a full-ring positron emission tomography (PET) system in patients with lung cancer. Twenty-seven patients (1 female, 26 males, age 62+/-9 years) with lung cancer or indeterminate pulmonary nodules were studied on the same day with a full-ring PET scanner (Siemens ECAT EXACT) and a coincidence gamma camera system (ADAC Vertex MCD). Sixty minutes after injection of 185-370 MBq FDG, a scan of the chest was performed with the full-ring system. Approximately 2 h p.i., the coincidence camera study was performed. Coincidence gamma camera (CGC) and PET images with (PETac) and without attenuation correction (PETnac) were analysed independently by two blinded observers. In addition, FDG uptake in primary tumours and involved lymph nodes was quantified relative to normal contralateral lung (T/L ratios). All primary tumours were histologically proven. The lymph node status was histologically determined in 23 patients. In four patients, no lymph node sampling was performed because of extensive disease or concurrent illnesses. In the 27 patients, 25 primary lung cancers and two metastatic lesions were histologically diagnosed. The number of coincidences per centimetre axial field of view was 3.33+/-0. 93x10(5) for the CGC and 1.09+/-0.36x10(6) for the dedicated PET system. All primary tumours (size: 4.6+/-2.6 cm) were correctly identified in the CGC and dedicated PET studies. T/L ratios were 4. 7+/-2.5 for CGC and 6.9+/-2.8 for PETnac (P <0.001). Histopathological evaluation revealed lymph node metastases in 11 of 88 sampled lymph node stations (size: 2.3+/-1.0 cm). All lymph node metastases were identified in the PETac studies, while PETnac detected 10/11 and CGC 8/11. For positive lymph nodes that were visible in CGC and PETnac studies, T/L ratios were 3.7+/-2.3 for CGC and 6.6+/-3.1 for PETnac (P=0.02). The diameters of false-negative lymph nodes in the CGC studies were 0.75, 1.5 and 2 cm. False-positive FDG uptake in lymph nodes was found in two patients with all three imaging methods. For all lesions combined, T/L ratios in CGC relative to PETnac studies decreased significantly with decreasing lesion size (r=0.62; P<0.001). In conclusion, compared with a full-ring PET system the sensitivity of CGC imaging for detection of lung cancer is limited by a lower image contrast which deteriorates with decreasing lesion size. Nevertheless, the ability of CGC imaging to detect pulmonary lesions with a diameter of at least 2 cm appears to be similar to that of a full-ring system. Both systems provide a similar specificity for the evaluation of lymph node involvement.     

Diagnosis of myocardial viability by dual-head coincidence gamma camera fluorine-18 fluorodeoxyglucose positron emission tomography with and without non-uniform attenuation correction

This study assessed a dual-head coincidence gamma camera (hybrid PET) equipped with single-photon transmission for myocardial fluorine-18 fluorodeoxyglucose (FDG) imaging by comparing this technique with conventional positron emission tomography (PET) using a dedicated ring PET scanner. Twenty-one patients were studied with dedicated FDG ring PET and FDG hybrid PET for evaluation of myocardial glucose metabolism, as well as technetium-99m tetrofosmin single-photon emission tomography (SPET) to estimate myocardial perfusion. All patients underwent transmitted attenuation correction using germanium-68 rod sources for ring PET and caesium-137 point sources for hybrid PET. Ring PET and hybrid PET emission scans were started 61+/-12 and 98+/-15 min, respectively, after administration of 154+/-31 MBq FDG. Attenuation-corrected images were reconstructed iteratively for ring PET and hybrid PET (ac-hybrid PET), and non-attenuation-corrected images for hybrid PET (non-ac-hybrid PET) only. Tracer distribution was analysed semiquantitatively using a volumetric vector sampling method dividing the left ventricular wall into 13 segments. FDG distribution in non-ac-hybrid PET and ring PET correlated with r=0.36 (P<0.0001), and in ac-hybrid PET and ring PET with r=0.79 (P<0.0001). Non-ac-hybrid PET significantly overestimated FDG uptake in the apical and supra-apical segments, and underestimated FDG uptake in the remaining segments, with the exception of one lateral segment. Ac-hybrid PET significantly overestimated FDG uptake in the apical segment, and underestimated FDG uptake in only three posteroseptal segments. A three-grade score was used to classify diagnosis of viability by FDG PET in 136 segments with reduced perfusion as assessed by SPET. Compared with ring PET, non-ac-hybrid PET showed concordant diagnoses in 80 segments (59%) and ac-hybrid PET in 101 segments (74%) (P<0.001). Agreement between ring PET and non-ac-hybrid PET was best in the basal lateral wall and in the apical-septal segment (80%-100%), and lowest in the apical, supra-apical and posteroseptal segments (41%-55%). Ac-hybrid PET showed highest agreement in the lateral wall (89%-100%), and lowest agreement in the apical and the basal septal segments (59%-67%). In conclusion, non-uniform attenuation correction with singles transmission significantly improves the diagnostic accuracy of myocardial dual-head gamma camera coincidence imaging with FDG. However, results equivalent to those obtained with ring PET cannot yet be attained, even if attenuation correction is applied. New rebinning algorithms for three-dimensional data may further improve the performance of ac-hybrid PET and should be evaluated in future studies.     

Diagnosis of myocardial viability by dual-head coincidence gamma camera fluorine-18 fluorodeoxyglucose positron emission tomography with and without non-uniform attenuation correction

This study assessed a dual-head coincidence gamma camera (hybrid PET) equipped with single-photon transmission for myocardial fluorine-18 fluorodeoxyglucose (FDG) imaging by comparing this technique with conventional positron emission tomography (PET) using a dedicated ring PET scanner. Twenty-one patients were studied with dedicated FDG ring PET and FDG hybrid PET for evaluation of myocardial glucose metabolism, as well as technetium-99m tetrofosmin single-photon emission tomography (SPET) to estimate myocardial perfusion. All patients underwent transmitted attenuation correction using germanium-68 rod sources for ring PET and caesium-137 point sources for hybrid PET. Ring PET and hybrid PET emission scans were started 61ᆠ and 98ᆣ min, respectively, after administration of 154ᆳ MBq FDG. Attenuation-corrected images were reconstructed iteratively for ring PET and hybrid PET (ac-hybrid PET), and non-attenuation-corrected images for hybrid PET (non-ac-hybrid PET) only. Tracer distribution was analysed semiquantitatively using a volumetric vector sampling method dividing the left ventricular wall into 13 segments. FDG distribution in non-ac-hybrid PET and ring PET correlated with r=0.36 (P<0.0001), and in ac-hybrid PET and ring PET with r=0.79 (P<0.0001). Non-ac-hybrid PET significantly overestimated FDG uptake in the apical and supra-apical segments, and underestimated FDG uptake in the remaining segments, with the exception of one lateral segment. Ac-hybrid PET significantly overestimated FDG uptake in the apical segment, and underestimated FDG uptake in only three posteroseptal segments. A three-grade score was used to classify diagnosis of viability by FDG PET in 136 segments with reduced perfusion as assessed by SPET. Compared with ring PET, non-ac-hybrid PET showed concordant diagnoses in 80 segments (59%) and ac-hybrid PET in 101 segments (74%) (P<0.001). Agreement between ring PET and non-ac-hybrid PET was best in the basal lateral wall and in the apical-septal segment (80%-100%), and lowest in the apical, supra-apical and posteroseptal segments (41%-55%). Ac-hybrid PET showed highest agreement in the lateral wall (89%-100%), and lowest agreement in the apical and the basal septal segments (59%-67%). In conclusion, non-uniform attenuation correction with singles transmission significantly improves the diagnostic accuracy of myocardial dual-head gamma camera coincidence imaging with FDG. However, results equivalent to those obtained with ring PET cannot yet be attained, even if attenuation correction is applied. New rebinning algorithms for three-dimensional data may further improve the performance of ac-hybrid PET and should be evaluated in future studies.     

Evaluation of treatment response to radiotherapy in head and neck cancer with fluorine-18 fluorodeoxyglucose

Nineteen patients with malignant head and neck tumors were imaged before and during radiation therapy with 18F-2-fluoro-2-deoxy-D-glucose (FDG) to study the effect of radiotherapy (RT) on FDG uptake. All tumor images were FDG-positive before treatment. After RT, a decrement of tumor FDG uptake was found in all but two patients; these were nonradioresponders. There was a significant decrement (p less than 0.001) in uptake ratios after irradiation of 30 +/- 5 Gy among the radioresponsive (CR + PR) but not among the radioresistant (NC + PD) tumors. The administered dose of RT correlated (r = 0.47, p less than 0.05) with the decrement in FDG activity among the CR + PR but not among the NC + PD patients. The biologic half-life of FDG radioactivity in tumor tissue was evaluated by dynamic scintigraphy. A change in the half-life of FDG toward the value observed in normal tissue was associated with treatment response. The results suggest that FDG imaging can be used for follow-up of RT in patients with head and neck cancer.     

The detection of local recurrent head and neck cancer with fluroine-18 fluorodeoxyglucose dual-head positron emission tomography

Primary tumors of the larynx and hypopharynx are preferably treated with high-dose radiation therapy. In these patients, it may be difficult to distinguish recurrent disease from post-treatment reactions. The aim of the present study was to assess the value of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) in the detection of local relapses of laryngeal or hypopharyngeal carcinoma after radiotherapy using a dual-head PET camera. Forty-eight patients (43 male, 5 female; mean age ±SD, 61±9.5 years) with suspected recurrent laryngeal or hypopharyngeal cancer were prospectively studied. The mean interval between initial treatment and suspicion of recurrent disease was 14.6 months (range: 3–100 months). FDG dual-head PET was followed by endoscopy with or without biopsy under general anaesthesia within a period of 2 months in all patients. The mean period of follow-up after FDG dual-head PET was 13.7 months. In 19 out of 31 patients with focally increased uptake, tumour recurrence (mean diameter: 2.4 cm; range 0.4–6.5 cm) was found at initial endoscopy. In five patients recurrence was found during follow-up with a mean interval of 6.6 months. Seven patients had a false-positive study due to benign lesions or swallowing artefacts. In none of the patients with a normal PET study was tumour recurrence found during follow-up. The sensitivity and specificity of FDG dual-head PET were 100% and 71%, respectively. It is concluded that FDG dual-head PET is highly sensitive for the detection of local recurrence of laryngeal and hypopharyngeal carcinoma after radiotherapy. Some lesions were detected with a mean interval of 6.6 months before histological confirmation. In patients suspected of having recurrent laryngeal or hypopharyngeal cancer in whom FDG-PET is negative, endoscopy may be omitted for at least 6 months and possibly for up to 1 year. Received 27 January and in revised form 15 March 1999     

Feasibility of fluorodeoxyglucose dual-head gamma camera coincidence imaging in the evaluation of lung cancer: comparison with FDG PET.

The purpose of this study was to elucidate the feasibility of fluorodeoxyglucose gamma camera coincidence imaging (FDG GCI) in the evaluation of lung cancer in comparison with FDG PET. METHODS: Twenty-three patients with recently diagnosed lung cancer were examined with both FDG PET and FDG GCI on the same day. Pulmonary lesions were analyzed visually and semiquantitatively using the ratio of lesion-to-background counts (L/B ratio). The L/B ratio of FDG PET without attenuation correction (AC) was also calculated and compared. Nodal stations were only visually analyzed. RESULTS: FDG GCI and FDG PET could detect 22 and 23, respectively, of 23 pulmonary lesions by visual analysis (95.7% versus 100%). The L/B ratio of FDG GCI was 4.26 +/- 2.55, and significantly lower than that of FDG PET (9.29 +/- 4.95; P < 0.01). The L/B ratio of FDG PET was significantly higher with AC than that without AC (9.29 +/- 4.95 vs. 6.66 +/- 4.65; P < 0.01). When the L/B ratio threshold was set at 5.0 for FDG PET and 2.7 for FDG GCI, their sensitivity was 87.0% and 73.9%, respectively. Of the 3 and 6 patients with false-negative results on semiquantitative analysis, the lesions in 3 patients on FDG PET and 4 patients on FDG GCI were less than or equal to 2.0 cm in greatest diameter, respectively. In the assessment of mediastinal involvement, FDG PET was 77.8% sensitive, 78.6% specific and 78.3% accurate, whereas FDG GCI was 77.8% sensitive, 92.9% specific and 87.0% accurate. In the hilar regions, FDG PET was 100% sensitive, 84.2% specific and 87.0% accurate, whereas FDG GCI was 75.0% sensitive, 89.5% specific and 87.0% accurate. CONCLUSION: In this study, FDG GCI yielded results comparable to FDG PET on visual analysis to detect pulmonary lesions and lymph node metastases. However, the lesion-to-background contrasts of pulmonary lesions and nodal involvement were lower in FDG GCI than in FDG PET. Comparison between the L/B ratio of FDG PET with and without AC indicated that, with AC, FDG GCI would be closer to FDG PET in the evaluation of lung cancer.     

The clinical value of 18F-FDG detection with a dual-head coincidence camera: a review.

Positron emission tomography (PET) has evolved into a technique that can accurately determine the distribution of positron-emitting radionuclides. The addition of a coincidence detection mode to a standard dual-head detector system has resulted in the option of single-photon and annihilation coincidence detection. This new device for imaging fluorine-18 2-fluoro-2-deoxy-D-glucose (18F-FDG) accumulation in neoplasms became commercially available in 1994. Besides conventional low-energy imaging in the collimated single-photon mode, it offers a relatively inexpensive opportunity to perform uncollimated PET by switching to the coincidence acquisition mode. This review summarises the clinical value of 18F-FDG detection with a dual-head coincidence camera in oncology. The results are compared with the overall results obtained using dedicated PET scanners. With respect to head and neck tumours, 18F-FDG coincidence mode gamma camera imaging (CGI) yields results that are in agreement with those obtained with dedicated PET scanners. With regard to other malignancies, such as lung cancer, lymphoma and brain tumours, data in the literature are too scarce to draw any definite conclusions. In general, the results of 18F-FDG CGI in tumours >15 mm seem to be comparable to those obtained with dedicated PET scanners, whereas in tumours <15 mm, the relative sensitivity of 18F-FDG CGI is approximately 80%. Using attenuation correction, the diagnostic yield of 18F-FDG CGI may increase. However, further clinical investigation is required to definitely establish its value in staging primary disease, therapy monitoring and assessment of tumour recurrence in clinical oncology.     

Power Doppler sonography of cervical lymph nodes in patients with head and neck cancer.

PURPOSEThe purpose of this preliminary study was to evaluate the usefulness of power Doppler sonography in differentiating metastatic from nonmetastatic cervical lymph nodes in patients with cancer.METHODSHistologically proved metastatic (n = 71) and nonmetastatic (n = 220) lymph nodes were examined with power Doppler sonography in 77 patients with head and neck cancer. Power Doppler sonography was assessed for its ability to differentiate metastatic from nonmetastatic lymph nodes.RESULTSPower Doppler sonography showed characteristic features of parenchymal blood flow signal in 59 (83%) of the 71 metastatic lymph nodes. By contrast, only four (2%) of the 220 nonmetastatic nodes showed these power Doppler signals. In addition, power Doppler sonography showed high levels of sensitivity (83%) and specificity (98%) in depicting metastatic lymph nodes, which were superior to the values (66% sensitivity and 92% specificity) obtained by applying size criteria (transverse to longitudinal ratio). However, a combination of the two criteria (parenchymal color signal and transverse to longitudinal ratio) improved diagnostic accuracy to 92% sensitivity and 100% specificity.CONCLUSIONOur preliminary findings suggest that the power Doppler criteria of no hilar flow, peripheral parenchymal nodal flow, and a transverse to longitudinal ratio of more than 0.65 together constitute a powerful tool for depicting metastatic lymph nodes in patients with cancer.     

Imaging of cervical lymph nodes in head and neck cancer: the basics

Imaging can identify pathologic cervical adenopathy in a significant number of patients with head and neck cancer who have no palpable adenopathy on physical examination. This article reviews nodal classification, drainage patterns of different head and neck cancers, various cross-sectional imaging features of metastatic lymph nodes from head and neck cancer, nodal staging, and certain features like extracapsular spread and carotid and vertebral invasion that the clinician should know because they have therapeutic and prognostic implications. New imaging techniques and the role of fluorodeoxyglucose positron emission tomography imaging in recurrent disease are discussed.     

Mediastinal staging of lung cancer with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose positron emission tomography and a dual-head coincidence gamma camera

The aims of the present study were (a) to evaluate mediastinal staging in patients with lung cancer with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) using a coincidence gamma camera (hybrid PET) in comparison with dedicated positron emission tomography (PET) and computed tomography (CT), and (b) to assess the feasibility to determine standardized uptake values (SUV) with hybrid PET. Forty patients were included in the study. Hybrid PET was performed without and with attenuation correction. Data were rebinned with single-slice (SSRB) or Fourier rebinning (FORE). The SUVs of primary tumors were calculated with hybrid PET and compared with SUVs determined by dedicated PET. Diagnostic accuracy for hybrid with or without attenuation correction was 80 or 74% compared with 82% for dedicated PET, and 63% for CT. Attenuation-corrected hybrid PET revealed a higher specificity than CT (83 vs 52%; p<0.05). The SUVs of primary tumors were similar to those of hybrid PET and dedicated PET with a mean relative difference of 20.8±16.4%. The FORE improved the agreement of SUVs with a mean relative difference of 13.8±9.9 vs 36.0±17.9% for SSRB (p<0.001). Hybrid PET with attenuation correction is more specific than CT for mediastinal staging in patients with lung cancer (p<0.05). It reveals similar results in comparison with dedicated PET. Calculation of SUVs with hybrid PET is feasible. Electronic Publication     

The clinical value of 18F-FDG detection with a dual-head coincidence camera: a review

Positron emission tomography (PET) has evolved into a technique that can accurately determine the distribution of positron-emitting radionuclides. The addition of a coincidence detection mode to a standard dual-head detector system has resulted in the option of single-photon and annihilation coincidence detection. This new device for imaging fluorine-18 2-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) accumulation in neoplasms became commercially available in 1994. Besides conventional low-energy imaging in the collimated single-photon mode, it offers a relatively inexpensive opportunity to perform uncollimated PET by switching to the coincidence acquisition mode. This review summarises the clinical value of ¹⁸F-FDG detection with a dual-head coincidence camera in oncology. The results are compared with the overall results obtained using dedicated PET scanners. With respect to head and neck tumours, ¹⁸F-FDG coincidence mode gamma camera imaging (CGI) yields results that are in agreement with those obtained with dedicated PET scanners. With regard to other malignancies, such as lung cancer, lymphoma and brain tumours, data in the literature are too scarce to draw any definite conclusions. In general, the results of ¹⁸F-FDG CGI in tumours >15 mm seem to be comparable to those obtained with dedicated PET scanners, whereas in tumours <15 mm, the relative sensitivity of ¹⁸F-FDG CGI is approximately 80%. Using attenuation correction, the diagnostic yield of ¹⁸F-FDG CGI may increase. However, further clinical investigation is required to definitely establish its value in staging primary disease, therapy monitoring and assessment of tumour recurrence in clinical oncology.     

Preliminary assessment of fluorine-18 fluorodeoxyglucose positron mission tomography in patients with bladder cancer

The purpose of this study was to assess the feasibility of imaging of bladder cancer with fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) scanning. We studied 12 patients with histologically proven bladder cancer who had undergone surgical procedures and/or radiotherapy. Retrograde irrigation of the urinary bladder with 1000–3710 ml saline was performed during nine of the studies. Dynamic and static PET images were obtained, and standardized uptake value images were reconstructed. FDG-PET scanning was true-positive in eight patients (66.7%), but false-negative in four (33.3%). Of 20 organs with tumor mass lesions confirmed pathologically or clinically, 16 (80%) were detected by FDG-PET scanning. FDG-PET scanning detected all of 17 distant metastatic lesions and two of three proven regional lymph node metastases. FDG-PET was also capable of differentiating viable recurrent bladder cancer from radiation-induced alterations in two patients. In conclusion, these preliminary data indicate the feasibility of FDG-PET imaging in patients with bladder cancer, although a major remaining pitfall is intense FDG accumulation in the urine. Present address: Department of Radiology, National Defense Medical College, 3-2 Namiki, Tokorozawa 359, Japan     

The benefit of functional-anatomical imaging with [18F]fluorodeoxyglucose utilizing a dual-head coincidence gamma camera with an integrated X-ray transmission system in non-small cell lung cancer

AIM: To evaluate functional-anatomical imaging with 2-[F]fluoro-2-deoxy-D-glucose (F-FDG) utilizing a dual-head coincidence gamma camera with an integrated X-ray transmission system for attenuation correction, anatomical mapping, and image fusion compared to conventional diagnostics by computed tomography (CT) in non-small cell lung cancer (NSCLC). METHODS: Thirty-five patients with NSCLC underwent FDG imaging of the thoracic area using a dual-head coincidence gamma camera (DHC) with an integrated X-ray transmission system. State-of-the-art CT scans had been performed before. Whole-body dedicated FDG positron emission tomography (PET) was performed immediately prior to DHC. Staging by CT and DHC, and DHC with integrated image fusion (FDHC) were re-evaluated with regard to detectable lesions, correct anatomical diagnoses, and clinical impact. Results of DHC and PET were compared for analysis of limitations of DHC. RESULTS: One hundred and thirteen tumour lesions were identified by CT. DHC detected 128 lesions overall: 102 true positive CT lesions were confirmed, 25 additional lesions were detected which affected staging in eight patients, and one false positive lung lesion did not show up in DHC. Nine CT lesions were missed by DHC (lymph node and lung). PET detected 150 areas of focally enhanced uptake, delivering two false positive results (nuchal muscles, pneumonia). Final evaluation confirmed 148 malignant lesions. Compared to CT, the results of DHC changed staging or treatment in 8/35 patients (23%). Lesion detection by DHC was limited by tumour size and intensity of FDG uptake. Image fusion provided relevant clinical information in 9/35 patients (26%). CONCLUSION: Functional imaging in NSCLC with this dual-head gamma camera is superior to morphological imaging by CT, although inferior to dedicated PET imaging. Combined functional-anatomical imaging has the potential to improve staging and localization procedures before surgery or radiotherapy.