Tau uptake in agrammatic primary progressive aphasia with and without apraxia of speech.

BACKGROUND AND PURPOSE: The non-fluent/agrammatic variant of primary progressive aphasia (agPPA) is a heterogeneous diagnosis wherein some individuals have apraxia of speech (AOS). When agPPA includes AOS, a tauopathy is the likely underlying pathology. Recently, [18F]AV-1451 was developed for the in-vivo assessment of tau. In this study, we compared patterns of tau tracer uptake in patients with agPPA with and without AOS. METHODS: Nine patients with agPPA (four without AOS) underwent tau positron emission tomography imaging with [18F]AV-1451. Uptake of [18F]AV-1451 was assessed as cortical to cerebellar crus ratio (standard uptake value ratio) in cortical regions of interest measured using the MCALT atlas and compared voxel-wise in SPM12. Each patient was age- and sex-matched to three controls. RESULTS: The agPPA without AOS showed uptake in the left frontal and temporal lobes, whereas agPPA with AOS showed uptake in the bilateral supplementary motor areas, frontal lobes, precuneus and precentral gyrus relative to controls. The left precentral gyrus had uptake in agPPA with AOS relative to those without AOS. CONCLUSIONS: This cross-sectional study suggests that [18F]AV-1451 uptake in the precentral gyrus is implicated in AOS in agPPA.

Regional ß-amyloid burden does not correlate with cognitive or language deficits in Alzheimer's disease presenting as aphasia.

BACKGROUND AND PURPOSE: A subset of patients with Alzheimer's disease (AD) present with early and prominent language impairment (aphasic AD). Our previous study demonstrated an association between global ß-amyloid burden measured on [(11)C] Pittsburgh compound B (PiB) positron emission tomography and general cognitive impairment, but not with aphasia, in such subjects. As a follow-up, whether there is any association between regional ß-amyloid burden, atrophy on magnetic resonance imaging (MRI) and global cognitive impairment, aphasia or other cognitive and functional impairment in aphasic AD is assessed. METHODS: Forty-four aphasic AD subjects who underwent PiB scanning and volumetric MRI and were determined to be positive for ß-amyloid deposition were analyzed. All had completed detailed neurological, neuropsychological and language batteries. Spearman's rank-order correlation was utilized to assess for associations. RESULTS: Greater visuospatial impairment was associated with increased ß-amyloid burden in the primary visual cortex (P = 0.001). Although there were many trends for associations between neurocognitive and language deficits and regional ß-amyloid burden, there were no strong associations that survived correction for multiple comparisons. However, neurocognitive and language impairment in these subjects strongly correlated with the degree of left lateral temporal and inferior parietal atrophy (P < 0.004). CONCLUSIONS: The findings from this study suggest a close relation between the severity of regional atrophy and cognitive and language impairment, but argue against a strong association between regional ß-amyloid burden and such deficits in aphasic AD subjects. Hence, other pathological factors may be driving the previously identified association between global ß-amyloid deposition and general cognitive impairment in aphasic AD.

Assessment of disease activity in rheumatoid arthritis using a novel folate targeted radiopharmaceutical Folatescan.

OBJECTIVES: Development of a simple and accurate technique for detecting active inflammation in the joints and other tissues of patients with inflammatory disorders is an unmet need in rheumatic diseases. This study is a preliminary assessment of the safety and usage of a radiopharmaceutical, FolateScan (Technetium-99m EC20; 99mTc-EC20), for detecting disease activity in patients with rheumatoid arthritis. METHODS: EC20 is a folate-targeted diagnostic radiopharmaceutical which binds to the folate receptor and is preferentially taken up by activated macrophages. In this open-label, cross-sectional study, a total of 40 patients with RA (26 with one or more swollen joints, 14 with clinically quiescent joint disease; 0/66 joint count) as well as 6 patients with osteoarthritis, 12 patients with other inflammatory conditions and 5 healthy subjects received 0.1 mg of EC20 labeled with 20-25mCi of technetium-99m. Disease activity was scored in each joint and other target tissues by a radiologist blinded to the clinical assessment, and results were compared to the rheumatologist's physical examination, which served as the test standard. RESULTS: The 40 patients (78% female) with RA had a mean age of 56.9 years. Assessment of uptake of 99mTc-EC20 in joints of patients with RA based on image analysis was compared to the clinical examination. FolateScan detected more actively involved joints in 27 patients (68%) than joints recorded as "swollen", and more actively involved joints in 25 patients (63%) than joints recorded as "painful and/or swollen". The number of swollen joints by clinical exam was correlated with ESR (r=0.43; p=0.006) and C-rp (r=0.35; p=0.03). The number of actively involved joints by FolateScan was also correlated with ESR (r=0.47; p=0.002) and C-rp (r=0.36; p=0.02). Joint uptake was also seen in patients with osteoarthritis. CONCLUSION: FolateScan is a potentially useful tool for detection of disease activity in patients with RA and may be more sensitive than the physical examination.

[18F] AV-1451 uptake in corticobasal syndrome: the influence of beta-amyloid and clinical presentation.

Corticobasal syndrome (CBS) is a phenotypic manifestation of diverse pathologies, including Alzheimer's disease and 4-repeat tauopathies. Predicting pathology in CBS is unreliable and, hence, molecular neuroimaging may prove to be useful. The aim of this study was to assess regional patterns of uptake on [18F] AV-1451 PET in CBS and determine whether patterns of uptake differ according to beta-amyloid deposition or differing clinical presentations. Fourteen patients meeting criteria for CBS underwent Pittsburgh Compound B (PiB) and [18F] AV-1451 PET. Seven patients presented as CBS and seven presented with apraxia of speech (AOS) and later evolved into CBS. A global PiB summary was calculated and used to classify patients as PiB (-) or PiB (+). AV-1451 uptake was calculated in fourteen regions-of-interest, with values divided by uptake in cerebellar crus grey matter to generate standard uptake value ratios. AV-1451 uptake was considered elevated if it fell above the 95th percentile from a group of 476 cognitively unimpaired normal controls. Six of the 14 CBS patients (43%) were PiB (+), with three of these patients showing strikingly elevated AV-1451 uptake across many cortical regions. Of the eight PiB (-) patients, only those with AOS showed elevated AV-1451 uptake in supplementary motor area and precentral cortex compared to controls. No region of elevated AV-1451 uptake were observed in PiB (-) typical CBS patients without AOS. These results suggest that regional [18F] AV-1451 is variable in CBS and depends on the presence of beta-amyloid as well as clinical presentation such as AOS. PiB (+) CBS does not necessarily reflect underlying Alzheimer's disease; however, the possibility some of these patients will evolve into Alzheimer's disease over time cannot be excluded.

Phase I trial of systemic administration of Edmonston strain of measles virus genetically engineered to express the sodium iodide symporter in patients with recurrent or refractory multiple myeloma.

MV-NIS is an Edmonston lineage oncolytic measles virus expressing the human sodium iodide symporter-a means for monitoring by non-invasive imaging of radioiodine. Patients with relapsed, refractory myeloma who had explored all other treatment options were eligible for this Phase I trial. Cohort 1 was treated with intravenous MV-NIS, and Cohort 2 received cyclophosphamide 2 days prior to MV-NIS. Thirty-two patients were treated. Cohort 1 initially enrolled to four dose levels without reaching maximum tolerated dose (MTD) and subsequently to two higher dose levels when improved virus manufacture technology made it possible. MTD was not reached in Cohort 1, and TCID50 1011 is the dose being used in a Phase II trial of single agent MV-NIS. Grade 3-4 adverse events in both cohorts at all dose levels were: neutropenia (n=9); leukocyte count decreased (n=5); thrombocytopenia (n=2); and CD4 lymphocytes decreased, anemia and lymphopenia (each n=1). MV-N RNA sequences were amplified from gargle specimens, blood and urine. 123I scans were positive in eight patients. One patient achieved a complete response; transient drops in serum free light chains were seen in other patients. MV-NIS is capable of replicating before being cleared by the immune system. Oncolytic viruses offer a promising new modality for the targeted infection and destruction of disseminated myeloma.

Surveillance for recurrent head and neck cancer using positron emission tomography.

PURPOSE: Earlier detection of head and neck cancer recurrence may improve survival. We evaluated the ability of [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) to detect recurrence in a prospective trial using sequential PET scans. PATIENTS AND METHODS: Serial posttherapy FDG-PET was prospectively performed in 44 patients with stage III or IV head and neck cancer. PET was performed twice during the first posttreatment year (at 2 and 10 months after therapy) and thereafter as needed. After therapy, patients were grouped, based on tissue biopsies, into those who achieved a complete response (CR) and those who had residual disease (RD). Patients who achieved a CR were further grouped into those without evidence of disease and those who had recurrence by 1 year after completion of therapy. Disease status as determined by physical examination (PE), PET, and correlative imaging was compared. RESULTS: Eight patients were lost to follow-up and six had RD after therapy. Of the remaining 30 patients with a CR, 16 had recurrence in the first year after therapy. Five of these 16 patients had recurrence detected by PET only, four by PET and correlative imaging only, five by PE and PET only, and two by PE, correlative imaging, and PET. Only PET detected all recurrences in the first year. PET performed better than correlative imaging (P =.013) or PE (P =.002) in the detection of recurrence. CONCLUSION: PET can detect head and neck tumor recurrence when it may be undetectable by other clinical methods. FDG-PET permits highly accurate detection of head and neck cancer recurrence in the posttherapy period.

Prospective investigation of positron emission tomography in lung nodules.

PURPOSE: Solitary pulmonary nodules (SPNs) are commonly identified by chest radiographs and computed tomography (CT). Biopsies are often performed to evaluate the nodules further. An accurate, noninvasive diagnostic test could avoid the morbidity and costs of invasive tissue sampling. We evaluated the ability of fluorine-18 deoxyglucose positron emission tomography (FDG-PET) to discriminate between benign and malignant pulmonary nodules in a prospective, multicenter trial. METHODS: Eighty-nine patients who had newly identified indeterminate SPNs on chest radiographs and CT were evaluated with FDG-PET. PET data were analyzed semiquantitatively by calculating standardized uptake values (SUVs) as an index of FDG accumulation and also by a visual scoring method. PET results were compared with pathology results. RESULTS: Sixty SPNs were malignant and 29 were benign. Using SUV data, PET had an overall sensitivity and specificity for detection of malignant nodules of 92% and 90%. Visual analysis provided a slightly higher, but not statistically significant, sensitivity of 98% and lower specificity of 69%. For SPNs < or = 1.5 cm (34 of 89), the sensitivity and specificity of SUV and visual analysis were 80% and 95% and 100% and 74%, respectively. CONCLUSION: FDG-PET can accurately characterize indeterminate SPNs. PET imaging provides a noninvasive method to evaluate indeterminate SPNs, which can reduce the need for invasive tissue biopsy.

Cardiac phantom evaluation of simultaneously acquired dual-isotope rest thallium-201/stress technetium-99m SPECT images.

Simultaneously acquired dual-isotope 201Tl/99mTc SPECT studies were performed using cardiac and thoracic phantoms to evaluate the dual-isotope myocardial perfusion technique. Cardiac phantom images representing infarction, viable myocardium and various levels of ischemia were analyzed. Studies with and without attenuating media were performed, and myocardium-to-defect count ratios and defect sizes from dual-isotope SPECT images were compared to myocardium-to-defect count ratios and defect sizes from single-isotope (201Tl and 99mTc) SPECT images. Dual-isotope studies also were interpreted qualitatively. Studies with background activity simulating clinical conditions were performed and interpreted qualitatively. Myocardium-to-defect count ratios from both 99mTc and 201Tl were similar in single-isotope and dual-isotope SPECT images. Thallium-201 and 99mTc defect sizes were decreased slightly (mean +/- s.d., 1.0 +/- 1.7 cc for 201Tl and 0.7 +/- 1.0 cc for 99mTc) on dual studies when compared to single studies but were not statistically significant. Dual-isotope image simulations of normal, ischemic and infarcted and viable myocardium were correctly identified by experienced clinicians in 95% of the cases (21/22). Simultaneous dual-isotope 201Tl/99mTc SPECT imaging of cardiac phantoms produced images that had similar myocardium-to-defect count ratios to those produced using single-isotope techniques and were correctly evaluated on qualitative analysis. Changes in defect size related to dual-isotope imaging were minimal and not qualitatively important.

Optimum scanning protocol for FDG-PET evaluation of pulmonary malignancy.

UNLABELLED: FDG-PET can differentiate benign from malignant focal pulmonary opacities. We performed dynamic FDG-PET studies to determine the optimum time for emission data acquisition. METHODS: Patients with focal pulmonary abnormalities demonstrated by biopsy to be malignant (n = 10) or benign (n = 4) were evaluated with dynamic FDG-PET. Dynamic PET data were acquired as sequential 5-min images for 2.5 hr. Radioactivity concentration measurements of the focal abnormality, a similar area in the opposite lung, and both lungs in the field of view were made throughout the period of acquisition. Standardized uptake ratios (SUR) of the lesions were calculated. SUR data and lesion-to-background ratios were plotted. The time that the SUR provided the maximum separation between benign and malignant masses after FDG administration was determined. RESULTS: The SUR values provided the greatest separation between benign and malignant abnormalities beginning at 50 min and no advantage was identified in imaging later. Achievement of a 4:1 lesion-to-background ratio occurred by 50 min in malignant lesions. CONCLUSION: The acquisition of the emission data used in the evaluation of pulmonary malignancy should begin approximately 50 min after FDG administration.

Semiquantitative and visual analysis of FDG-PET images in pulmonary abnormalities.

UNLABELLED: FDG PET images of the thorax can be analyzed semiquantitatively using standardized uptake ratios (SUR) or activity ratios between abnormal and normal tissue, or qualitatively by visual comparison of the abnormality to normal structures. Standardized uptake ratio evaluation of FDG PET images has been shown to accurately differentiate benign from malignant focal pulmonary abnormalities. The accuracy of activity ratios and visual analysis have not been evaluated. We therefore prospectively analyzed FDG PET images in patients with pulmonary abnormalities to evaluate differences in analytic schemes. METHODS: We evaluated 107 patients with an indeterminate focal abnormality on chest radiograph or CT with FDG PET between November 1991 and March 1993. The PET studies were evaluated using SUR, activity ratios and visual analysis. Activity ratios of maximum activity/cc and average activity/cc between regions of interest (ROIs) in abnormalities and normal lung on the contralateral side were calculated. Visual interpretations were graded on a five-point scale of two observers' confidence of malignancy. FDG uptake in the abnormality was also visually graded in comparison to mediastinal activity. Receiver-operating characteristic (ROC) curve areas were generated for the SUR data, activity ratios and visual analysis. RESULTS: Of 88 patients in which a conclusive diagnosis was made, 61 (69%) patients had malignancy and 27 (31%) patients had a benign process. SUR, maximum activity ratio, average activity ratio and visual interpretation ROC curve areas were 0.96, 0.95, 0.92 and 0.96, respectively. CONCLUSIONS: SUR, activity ratios and visual evaluation are each equally accurate methods of FDG PET data analysis in differentiating malignant from benign focal pulmonary abnormalities.

Thoracic nodal staging with PET imaging with 18FDG in patients with bronchogenic carcinoma.

PURPOSE: To assess the role of positron emission tomographic (PET) imaging with 18-fluoro-2-deoxyglucose (18FDG) in detecting thoracic lymph node metastases in patients with bronchogenic carcinoma. MATERIALS AND METHODS: Over a 2-year period, any patient presenting to our institution with newly diagnosed bronchogenic carcinoma who was to have thoracic nodes sampled was considered eligible. All PET studies were performed prior to nodal sampling and areas of increased uptake were mapped according to the American Thoracic Society classification. Studies were correlated with CT and pathology. Sensitivity and specificity for predicting nodal metastases was calculated. RESULTS: Forty-two patients had 62 nodal stations (40 hilar/lobar, 22 mediastinal) sampled. The sensitivity and specificity for hilar/lobar lymph node station metastases using PET imaging was 73% and 76%, respectively. With CT, the sensitivity and specificity were 27% and 86%. The sensitivity and specificity using PET imaging for mediastinal node station metastases was 92% and 100%, respectively, while with CT the figures were 58% and 80%. The sensitivity and specificity for combined thoracic nodal station metastases using PET imaging was 83% and 82%, respectively, while with CT it was 43% and 85%. There was a strong statistical relationship between positive PET imaging and lymph node abnormalities. CONCLUSIONS: 18FDG-PET imaging is accurate in detecting thoracic lymph node metastases in patients with bronchogenic carcinoma. Normal results of PET studies virtually preclude the need for mediastinal nodal sampling prior to surgery, whereas abnormal results of studies most likely represent mediastinal metastases. Treatment can be based on the extent of disease suggested by PET imaging.

Detection of primary and recurrent lung cancer by means of F-18 fluorodeoxyglucose positron emission tomography (FDG PET).

Positron emission tomography (PET), with the glucose analog F-18 fluoro-deoxyglucose (FDG), takes advantage of the enhanced glucose uptake observed in neoplastic cells. We examined whether the detection of preferential FDG uptake with PET permits differentiation between benign and malignant focal pulmonary lesions in patients with suspected primary or recurrent lung cancer. Between November 1991 and September 1993, 100 patients with indeterminate focal pulmonary abnormalities including 16 patients who had previous lung resections for cancer were prospectively studied. Tissue diagnosis was obtained by transbronchial or percutaneous biopsy (n = 49) and open biopsy or resection (n = 35). Three patients underwent extended observation (> 2 years) alone. Excluded were 13 patients lacking firm pathologic diagnoses and less than 2-year follow-up. FDG activity in the lesion was expressed as a calculated standardized uptake ratio. Mean standardized uptake ratio (+/- standard deviation) was 6.6 (+/- 3.1) in 59 patients with cancer versus 2.0 (+/- 1.6) in 28 with benign disease (p = 0.0001; unpaired t test, two-sided). With a standardized uptake ratio > or = 2.5 used for detecting malignancy, sensitivity, specificity, and accuracy were 97% (57/59), 82% (23/28), and 92% (80/87), respectively. Notably, in patients evaluated for pulmonary abnormalities after lung resection for cancer, all chest recurrences were correctly identified. The exceptional sensitivity of FDG PET demonstrates that malignant pulmonary lesions preferentially accumulate FDG, which results in a standardized uptake ratio > or = 2.5. PET may be useful for distinguishing recurrent tumor from postoperative, or postradiation, changes. If performed in all patients before open biopsy, PET increases the diagnostic yield by reducing the number of patients who have benign lesions at operation. Moreover, by lowering expenditures for hospitalization and other diagnostic procedures, FDG PET may significantly reduce health care costs.

Positron emission tomography in lung cancer.

Reports on positron emission tomography have become more common in the oncology literature. After a short introduction to positron emission tomography, this review will look at the data relating to the use of this technology in the diagnosis, the staging, and the post-treatment evaluation of patients with lung cancer and will discuss its potential role in these evaluations.

Lung tumor growth correlates with glucose metabolism measured by fluoride-18 fluorodeoxyglucose positron emission tomography.

BACKGROUND: The growth rate, or doubling time, of radiographically indeterminate pulmonary abnormalities is an important determinant of malignancy. Prospective calculation of doubling time, however, delays diagnosis and treatment. Positron emission tomography (PET) using the glucose analogue fluoride-18 fluorodeoxyglucose (FDG) measures the enhanced glucose uptake characteristic of neoplastic cells. We postulated that if FDG activity correlates with doubling time, then PET may allow prompt diagnosis of lung cancer. METHODS: From March 1992 to July 1993, all patients with indeterminate focal pulmonary abnormalities were eligible for FDG PET imaging. In 53 patients, serial chest radiographs or computed tomograms were available and doubling time was computed. The FDG activity within the lesion was expressed as a standardized uptake ratio. RESULTS: The mean standardized uptake ratio (+/- SD) was 5.9 +/- 2.7 in 34 patients with cancer, versus 2.0 +/- 1.7 in 19 with benign disease (p < 0.001). Using a criterion of standardized uptake ratio 2.5 or greater for malignancy, the accuracy of PET was 92% (49 of 53). The standardized uptake ratio was significantly correlated with doubling time (r = -0.89; p = 0.002). CONCLUSION: These data suggest a direct relation between tumor growth and FDG uptake in lung cancer. The technique of FDG PET demonstrates exceptional accuracy and may permit prompt diagnosis of lung cancer.

Triple-technique (MR imaging, single-photon emission CT, and CT) coregistration for image-guided surgical evaluation of patients with intractable epilepsy.

Ictal and interictal single-photon emission CT (SPECT) play an increasingly important role in the surgical evaluation of patients with epilepsy. We present a method of coregistration of MR, SPECT, and CT images to correlate structural data (MR imaging), blood flow changes (SPECT), and location of subdural electrodes (CT) for patients undergoing image-guided surgical treatment of epilepsy. MR-SPECT root mean square (rms) mismatch distances were 2.1 to 2.5 mm, and MR-CT rms mismatch distances were 1.0 to 4.5 mm. Coregistration assisted in image-guided placement of subdural electrodes and in surgical resection of the suspected epileptogenic focus.

Overexpression of MPS antigens by squamous cell carcinomas of the head and neck: immunohistochemical and serological correlation with FDG positron emission tomography.

Survival from advanced primary or recurrent Squamous Cell Carcinoma (SCC) of the head and neck (H&N) is poor. More accurate detection of primary tumors and recurrence may provide ways to improve survival. No standard serum tumor marker is routinely used for surveillance of SCC-H&N. In this paper, we evaluated the performance characteristics of the MPS-H tumor marker test for the quantitative measurement of "MPS-H" heat-generated immunoreactive proteins and assessed the clinical utility of this marker in the detection and monitoring of SCC-H&N. In approximately 92% of the subjects having no evidence of SCC-H&N, the MPS-H levels were lower than 15 ng/mL. In 76% of patients having SCC-H&N at various stages (T1-T4), the MPS-H level was > 15 ng/mL (range: 20-200 ng/mL). In addition, we found a statistically significant correlation between PET positive cases and high MPS-H serum levels in SCC-H&N patients with recurrent disease. These results suggest that MPS-H may provide an initial screening test that would allow for selective PET imaging in these patients. Furthermore, we found that there was greater expression of MPS-1 in tumors of higher histological grades. Thus, in tumors with more histological aggressiveness there is more MPS-1, indicating the potential usefulness of this marker in prognosis for SSC-H&N. Considering the immunohistochemical, serological, and FDG-PET data presented here, and the compelling need to expedite the early diagnosis of primary and recurrent epithelial malignancies of the head and neck, we are further evaluating the system of MPS antigens in a large patient population as a tool for the early serologic and histologic diagnosis of SCC-H&N.

Positron emission tomography in the pretreatment evaluation and follow-up of non-small cell lung cancer patients treated with radiotherapy: preliminary findings.

The purpose of this study was to prospectively evaluate positron emission tomography (PET) for delineating lung cancers preradiotherapy and to assess PET's ability to distinguish residual tumor from scarring following radiotherapy. Between April 1991 and October 1992, 20 patients underwent 18fluoro-2-deoxyglucose (18FDG) PET scanning of the chest prior to radiotherapy for lung cancer. Tumor volumes on chest x-ray (CXR) and computerized tomography (CT) scan were correlated with abnormalities on PET scans. Follow-up PET studies were compared to postradiotherapy chest x-ray and/or CT scans, and correlated with clinical outcome. Six of seven well-demarcated tumors showed increased uptake of 18FDG correlating with the CT/CXR tumor volume. Twelve poorly demarcated tumors demonstrated increased 18FDG uptake. In seven of 12, the CT/CXR abnormality correlated with changes on PET scan. In three of 12, CT/CXR abnormalities were larger than on PET, whereas in two of 12, abnormalities on PET extended outside the region of CT/CXR changes. The 13th patient in the poorly demarcated category had diffuse carcinoma in situ at the surgical margin that demonstrates increased 18FDG uptake, but was not visible by CT/CXR. Of 12 patients with follow-up studies, all had changes on CXR and/or CT that made it difficult to assess response. Four of 12 had a complete response by PET; all remain locally controlled. The remaining eight patients had either a partial response (n = 6) or no response (n = 2) by PET. Four of these eight patients remain alive and well 11-24 months after therapy. 18FDG PET may be useful for delineation of lung cancer volumes that are poorly defined by CXR and/or CT scan. The value of PET in differentiating tumor from fibrosis after radiotherapy for lung cancer remains to be established.

18F-FDG labelling of human leukocytes.

Radiolabelled leukocytes are useful for the imaging of inflammation and infection, and 18F-fluorodeoxyglucose (18F-FDG) is known to concentrate in metabolically active cells. We evaluated the feasibility of leukocyte labelling with 18F-FDG using ACD and heparin anticoagulants at 20 degrees C and 37 degrees C, with and without gentle mixing during incubation. With leukocytes (WBC) harvested from 20 ml blood, studies were performed using 18F-FDG in concentrations of 3.7-74 MBq (0.1-2.0 mCi). 18F-FDG WBC stability in platelet-poor plasma was assessed at 1-4 h. Satisfactory labelling efficiency was achieved with incubation in heparin-saline at 37 degrees C for 30 min (62.7+/-1.6%), and was further enhanced by mixing during incubation (78.1+/-3.9%). Cell labelling was predominantly of granulocytes (78.5+/-1.4%). 18F-FDG WBC was relatively stable in platelet-poor plasma for up to 4 h, and no cell staining was observed in viability studies using trypan blue. These results indicate the feasibility of leukocyte labelling with 18F-FDG, providing an approach that may be useful in PET imaging of inflammation and infection.

Biodistribution and dosimetry of [(18)F]fluorodeoxyglucose labelled leukocytes in normal human subjects.

SUMMARY: This study was performed in order to assess [(18)F]fluorodeoxyglucose white blood cell ((18)F-FDG WBC) dosimetry in normal human subjects. Using previously reported methods, mixed cell suspensions of autologous leukocytes were prepared from four normal volunteers. Leukocytes were labelled in heparin-saline by incubation with (18)F-FDG at 37 degrees C for 20 min. After washing and resuspension, (18)F-FDG WBCs (225-315 MBq) were administered by intravenous injection. Whole-body imaging was performed at 0.5, 1, 2, 4 and 6 h using a GE Varicam with 511 keV collimation. Blood samples were obtained at corresponding times as well as fractionated urinary collection. Whole-body anterior and posterior images were used for calculation of organ dosimetry. Uptake of (18)F-FDG WBCs occurred predominantly within the reticulo-endothelial system. Plasma activity, urinary excretion (9.9+/-2.3% at 6 h), and brain uptake (1.7+/-0.4%) were consistent with partial elution of (18)F-FDG. Positron emission tomography imaging performed at 5-6 h after injection yielded good quality images of reticulo-endothelial uptake. Whole-body and organ dosimetry for (18)F-FDG WBCs in doses of 225-250 MBq are comparable with reported results for conventional doses of (111)In oxine labelled leukocytes. Further studies of (18)F-FDG WBC as an agent for positron emission tomography imaging of inflammatory disease appear warranted.

The use of lymphoscintigraphy and PET in the management of head and neck melanoma.

OBJECTIVES: Lymphoscintigraphy with sentinel node dissection and 18 fluoro-2-deoxyglucose positron emission tomography (PET) are being used independently in the management of many intermediate and thick melanomas of the head and neck. We report a series of patients with melanoma of the head and neck with Breslow depths greater than 1.0 mm and clinically negative regional nodes that were evaluated prospectively with PET and lymphoscintigraphy. STUDY DESIGN AND SETTING: Between July 1, 1998 and December 30, 2000 PET scans were obtained preoperatively on 18 patients undergoing resection of head and neck melanoma. Lymphoscintigraphy and sentinel node dissection was performed. Resection of the primary lesion was then carried out with adequate margins and the defects were reconstructed. RESULTS: Sentinel node(s) were found in 17/18 patients (94.4%); 5/18 (27.8%) of cases had metastases. PET detected nodal metastasis preoperatively in 3 patients (16.7%), one of which had a positive sentinel node dissection. CONCLUSION: PET and lymphoscintigraphy offer complimentary ways of evaluation for metastatic melanoma.