Paul V. Kison

Demonstration of accuracy and clinical versatility of mutual information for automatic multimodality image fusion using affine and thin-plate spline warped geometric deformations

This paper applies and evaluates an automatic mutual information-based registration algorithm across a broad spectrum of multimodal volume data sets. The algorithm requires little or no pre-processing, minimal user input and easily implements either affine, i.e. linear or thin-plate spline (TPS) warped registrations. We have evaluated the algorithm in phantom studies as well as in selected cases where few other algorithms could perform as well, if at all, to demonstrate the value of this new method. Pairs of multimodal gray-scale volume data sets were registered by iteratively changing registration parameters to maximize mutual information. Quantitative registration errors were assessed in registrations of a thorax phantom using PET/CT and in the National Library of Medicines Visible Male using MRI T2-/T1-weighted acquisitions. Registrations of diverse clinical data sets were demonstrated including rotate-translate mapping of PET/MRI brain scans with significant missing data, full affine mapping of thoracic PET/CT and rotate-translate mapping of abdominal SPECT/CT. A five-point thin-plate spline (TPS) warped registration of thoracic PET/CT is also demonstrated. The registration algorithm converged in times ranging between 3.5 and 31 min for affine clinical registrations and 57 min for TPS warping. Mean error vector lengths for rotate-translate registrations were measured to be subvoxel in phantoms. More importantly the rotate-translate algorithm performs well even with missing data. The demonstrated clinical fusions are qualitatively excellent at all levels. We conclude that such automatic, rapid, robust algorithms significantly increase the likelihood that multimodality registrations will be routinely used to aid clinical diagnoses and post-therapeutic assessment in the near future.

Preclinical and clinical studies of bone marrow uptake of fluorine-1-fluorodeoxyglucose with or without granulocyte colony-stimulating factor during chemotherapy.

PURPOSE To evaluate the effect of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) on bone marrow glucose metabolism in rodents and in patients, as assessed by 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) uptake measured directly or by positron-emission tomography (PET) scanning. MATERIALS AND METHODS Groups of three rats received either daily saline, G-CSF, or GM-CSF injections for 7 days. After treatment, FDG was injected and F-18 activities in tissues measured 1 hour later. Twenty-two breast cancer patients treated with multiagent chemotherapy were sequentially studied with PET. Eleven patients received G-CSF therapy as an adjunct to chemotherapy, while 11 received chemotherapy only. The standardized uptake value-lean (SUL) of bone marrow FDG uptake was measured and compared. RESULTS In rats, bone marrow F-18 activity was significantly higher in both CSF groups than in the saline group (G-CSF, 0.44 +/- 0.08; GM-CSF, 0.33 +/- 0.02; saline, 0.18 +/- 0.02% injected dose [ID]/g x kg; P < .05), but the other normal tissues had comparable biodistributions to controls. In breast cancer patients, the FDG uptake of bone marrow did not change with chemotherapy alone; however, marrow uptake was increased after treatment with G-CSF. The dose of G-CSF and duration of treatment were correlated with the extent of increase in FDG uptake. The SUL of bone marrow was as follows: baseline, 1.56 +/- 0.23; after one cycle, 3.13 +/- 1.40 (P < .01); after two cycles, 2.22 +/- 0.85 (P < .05); and after three cycles, 2.14 +/- 0.79 (P < .05), respectively. Although the FDG uptake of bone marrow declined after G-CSF treatment was completed, it was higher than the baseline level for up to 4 weeks postcompletion of G-CSF and the elevated marrow FDG uptake was sustained longer than the period of blood neutrophil count elevation. CONCLUSION Substantial increases in bone marrow FDG uptake are rapidly induced by CSF treatments and should not be misinterpreted as diffuse bone marrow metastases.

Preliminary assessment of fluorine-18 fluorodeoxyglucose positron emission 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.

FDG-PET determination of metabolically active tumor volume and comparison with CT

PURPOSE: To determine if tumor volume, in addition to tumor metabolic activity, can be assessed noninvasively from attenuation-corrected fluorodeoxyglucose (FDG)-PET imaging using a semiautomated method.METHODS: CT and FDG-PET scanning was performed in 14 patients, eight with newly diagnosed untreated malignancies, and six patients with progressive non-Hodgkins lymphoma (NHL). Tumor volume was determined from CT scans by summation of manually drawn regions of interest over tumor. Tumor volume was determined at FDG-PET with a semiautomated method based on quantitation of (18)F uptake and thresholding.RESULTS: Mean tumor volume was 187 +/- 189 cm(3). Tumor volume determined by means of PET and CT was strongly correlated in the patients with untreated tumors. Correlation was weaker for all patients, mainly due to one previously treated patient with a large disparity between CT and metabolically active tumor volumes at FDG-PET, presumably due to tumor necrosis.CONCLUSIONS: Tumor volume determination by FDG-PET was strongly correlated with tumor volumes determined by anatomic imaging with CT. FDG-PET appears comparable to CT in measuring untreated tumor volumes of this size. FDG-PET may be superior to anatomic techniques in assessing metabolically active tumor volume, and warrants further study in this role.

Uptake of 2-deoxy-2-[18F]fluoro-d-glucose in the normal testis: Retrospective PET study and animal experiment

Our retrospective PET and animal studies were conducted on a total of eight patients with normal testes and five male Sprague-Dawley rats. All the rats were necropsied at 60 minute post-injection of FDG, and the organs were removed and counted. The human testes were visualized on 60–70 minute FDG-PET images and whole- or partial-body images in all of the patients. The correlations between patient age over 50 years old and testis-to-muscle ratios, and patient age and SUVs were statistically significant, r = − 0.755, p < 10−6 (n = 7), r = − 0.900, p < 0.007 (n = 4), respectively. FDG uptake of the rat testes was 0.162 ± 0.004% kg injected dose/g (n = 5). The uptake was approximately 6.0 and 3.6 times as high as muscle and blood levels, respectively. In conclusion, there is substantial uptake of FDG into the normal testis which declines with age. The normal levels of FDG uptake in the testis relative to the patient’s age should be considered in the interpretation of FDG scans of the inguinal and lower pelvic regions.