Quantification method in [18F]fluorodeoxyglucose brain positron emission tomography using independent component analysis.

OBJECTIVE: To extract accurate image-derived input functions from dynamic brain positron emission tomography images (DBPIs) using independent component analysis (ICA). METHODS: A modified linear model with haematocrit correction was used to improve the accuracy of input functions estimated by independent component analysis and to reduce the error of quantitative analysis. Two types of material were examined: (1) a simulated dynamic phantom with a three-compartment, four-parameter model; (2) clinical 2-h DBPIs with a standard plasma sampling procedure. The input function was extracted from DBPIs using independent component analysis. The modified linear model with haematocrit correction was used to obtain the independent component analysis-estimated input function (Iica). For comparison, the input function derived from the last three blood samples (Iest) was used. The image-derived input functions (Iica and Iest) were compared with the input function from blood sampling (Itp). The mean percentage error of the metabolic rate of [F]-2-fluoro-2-deoxy-D-glucose (MRFDG) was calculated for both Iica and Iest against that of Itp. RESULTS: In simulated studies, the mean percentage errors of MRFDG between true simulated and estimated values of Iest and Iica were 8.2% and 4.2%, respectively. In clinical studies, six clinical cases were collected. The mean percentage errors and standard deviations of MRFDG with Iest and Iica were 12.6+/-7.5% and 7.7+/-3.3%, respectively. CONCLUSIONS: We have proposed a technique for estimating image-derived input functions using independent component analysis without blood sampling. The results of our method were highly correlated with those from standard blood sampling, and more accurate than those of other methods proposed previously.

Gorham's disease: the disappearing bone.

Gorham's disease is a rare disorder characterized by proliferation of vascular channels. The clinical presentation of Gorham's disease is variable and depends on the site of involvement. A high index of clinical suspicion is needed for accurate diagnosis, and recognition of distinctive radiologic and histopathologic features can help facilitate and expedite diagnosis. The subsequent images were obtained from a 31-year-old male patient. Nuclear scintigraphy and computed tomography identified active bone destruction in the lower thoracic and upper lumbar spine in addition to the absence of the left lower rib cage. Gorham's disease was subsequently confirmed by biopsy.

Incidental finding of autosomal dominant polycystic kidney disease with liver involvement on Tc-99m sestamibi scintigraphy.

Autosomal dominant polycystic kidney disease is a systemic hereditary disease characterized by renal cysts and sometimes involvement of the liver. We present a 65-year-old woman with autosomal dominant polycystic kidney disease on regularly hemodialysis who recently experienced intermittent right upper quadrant abdominal pain and elevated intact parathyroid hormone for more than a year. She was referred for double-phase Tc-99m sestamibi scintigraphy, under the impression of hyperparathyroidism. Apart form increased uptake in the right thyroid bed, the images showed a large photon-deficient area in the upper portion of the abdomen corresponding to the liver.

Biodistribution, pharmacokinetics and PET imaging of [(18)F]FMISO, [(18)F]FDG and [(18)F]FAc in a sarcoma- and inflammation-bearing mouse model.

UNLABELLED: 2-Deoxy-2-[(18)F]fluoro-d-glucose ([(18)F]FDG), [(18)F]fluoroacetate ([(18)F]FAc) and [(18)F]fluoromisonidazole ([(18)F]FMISO) were all considered to be positron emission tomography (PET) probes for tumor diagnosis, though based on different rationale of tissue uptake. This study compared the biodistribution, pharmacokinetics and imaging of these three tracers in a sarcoma- and inflammation-bearing mouse model. METHODS: C3H mice were inoculated with 2x10(5) KHT sarcoma cells in the right thigh on Day 0. Turpentine oil (0.1 ml) was injected in the left thigh on Day 11 to induce inflammatory lesion. Biodistribution, pharmacokinetics and microPET imaging of [(18)F]FMISO, [(18)F]FDG and [(18)F]FAc were performed on Day 14 after tumor inoculation. RESULTS: The inflammatory lesions were clearly visualized by [(18)F]FDG/microPET and autoradiography at 3 days after turpentine oil injection. The tumor-to-muscle and inflammatory lesion-to-muscle ratios derived from microPET imaging were 6.79 and 1.48 for [(18)F]FMISO, 8.12 and 4.69 for [(18)F]FDG and 3.72 and 3.19 for [(18)F]FAc at 4 h post injection, respectively. Among these, the tumor-to-inflammation ratio was the highest (4.57) for [(18)F]FMISO compared with that of [(18)F]FDG (1.73) and [(18)F]FAc (1.17), whereas [(18)F]FAc has the highest bioavailability (area under concentration of radiotracer vs. time curve, 116.2 hxpercentage of injected dose per gram of tissue). CONCLUSIONS: MicroPET images and biodistribution studies showed that the accumulation of [(18)F]FMISO in the tumor is significantly higher than that in inflammatory lesion at 4 h post injection. [(18)F]FDG and [(18)F]FAc delineated both tumor and inflammatory lesions. Our results demonstrated the potential of [(18)F]FMISO/PET in distinguishing tumor from inflammatory lesion.