Biomedical subjects

Mitsuaki Tatsumi

Publications and source records attributed to Mitsuaki Tatsumi.

At least 19 recordsLinked to original sources

PubMed2006

Correlation of GLUT-1 overexpression, tumor size, and depth of invasion with 18F-2-fluoro-2-deoxy-D-glucose uptake by positron emission tomography in colorectal cancer.

We investigated the wide variability of 18F-2-fluoro-2-deoxy-D: -glucose (FDG) uptake, semiquantified as standardized uptake value (SUV), in positron emission tomography (PET) scanning, in 20 patients with colorectal cancer (CRC), including 1 with synchronous hepatic metastasis. The sensitivity of PET in CRC diagnosis was 100%, with a mean SUV of 8.0 (3.1-11.9). Tumor size and depth of invasion were associated with higher SUVs (P=.0004, .042, respectively). Strong glucose transporter-1 (GLUT-1) expression had significantly positive correlation with the SUV (r=.619, P=.003). GLUT-1 expression revealed positive staining in 17 (85%) of the 20 primary lesions. The central part of the tumor, thought to be relatively hypoxic, had stronger GLUT-1 expression and a higher SUV than the periphery, in both the primary tumor and hepatic metastatic foci. Our data suggest that the SUVs of FDG uptake in PET may be a noninvasive biomarker for advanced CRC, indicative of a large hypoxic tumor with deep invasion.

Adenocarcinoma↗

PubMed2005

Initial experience with FDG-PET/CT in the evaluation of breast cancer.

PURPOSE: We retrospectively reviewed FDG-PET/CT images in patients with breast cancer to determine whether PET/CT improved the level of diagnostic confidence as compared with PET and to compare PET/CT and CT findings at the location of suspected malignancies. METHODS: The study included 75 patients with known breast cancer. The initial PET/CT study for each patient was retrospectively reviewed to determine whether improved diagnostic confidence (IDC) regarding lesion localization and characterization was observed with PET/CT as compared with PET alone. PET/CT and CT findings were compared regarding lesion characterization and staging in 69 of the 75 patients, and in the case of discordant findings, comparison with histological or informative follow-up results was also performed. RESULTS: Fifty of the 75 patients exhibited increased FDG uptake in a total of 95 regions. In the comparison of PET/CT and PET, PET/CT resulted in IDC in 30 (60%) of these 50 patients and in 52 (55%) of the 95 regions. In the comparison between PET/CT and CT in 69 patients, PET/CT demonstrated a significantly better accuracy than CT (P<0.05). PET/CT showed definitely positive findings in 60 regions with malignancies, among which CT exhibited positive findings in 43 (72%). PET/CT and CT accurately staged 59 (86%) and 53 (77%) of the 69 patients, respectively. CONCLUSIONS: PET/CT added incremental diagnostic confidence to PET in more than 50% of patients and regions with increased FDG uptake. PET/CT accurately detected more regions with malignancies than did CT. This initial evaluation suggests that PET/CT is preferable to PET or CT in the diagnosis of breast cancer.

Adult↗

PubMed2005

Dynamic imaging of allogeneic mesenchymal stem cells trafficking to myocardial infarction.

BACKGROUND: Recent results from animal studies suggest that stem cells may be able to home to sites of myocardial injury to assist in tissue regeneration. However, the histological interpretation of postmortem tissue, on which many of these studies are based, has recently been widely debated. METHODS AND RESULTS: With the use of the high sensitivity of a combined single-photon emission CT (SPECT)/CT scanner, the in vivo trafficking of allogeneic mesenchymal stem cells (MSCs) colabeled with a radiotracer and MR contrast agent to acute myocardial infarction was dynamically determined. Redistribution of the labeled MSCs after intravenous injection from initial localization in the lungs to nontarget organs such as the liver, kidney, and spleen was observed within 24 to 48 hours after injection. Focal and diffuse uptake of MSCs in the infarcted myocardium was already visible in SPECT/CT images in the first 24 hours after injection and persisted until 7 days after injection and was validated by tissue counts of radioactivity. In contrast, MRI was unable to demonstrate targeted cardiac localization of MSCs in part because of the lower sensitivity of MRI. CONCLUSIONS: Noninvasive radionuclide imaging is well suited to dynamically track the biodistribution and trafficking of mesenchymal stem cells to both target and nontarget organs.

Animals↗

PubMed2005

Fusion image of positron emission tomography and computed tomography for the diagnosis of local recurrence of rectal cancer.

BACKGROUND: The aim of this study was to evaluate the clinical and therapeutic value of digital fusion image (FI) of positron emission tomography (PET) using (18)F-fluorodeoxy glucose and computed tomography (CT) in patients who were suspected of having a local recurrence of rectal cancer. METHODS: Forty-two patients (32 men and 10 women; mean age, 61.4 years, range, 40-79 years) with a suspicion of local recurrence after curative resection of rectal cancer were prospectively recruited and underwent (18)F-fluorodeoxy glucose-PET and CT. The FI was reconstructed with a commercially available digital software program, T-B Fusion. Wilcoxon signed rank test was used to compare FI with CT alone or PET alone. RESULTS: FI yielded a correct diagnosis in 39 (93%) of 42 patients, whereas CT alone and PET alone did so in 33 (79%) and 37 (88%) patients, respectively. FI had better diagnostic accuracy than CT alone (P = .0138) and PET alone (P = .0156). Overall, FI altered patient management in 11 (26.2%) patients on the basis of additional information, including differentiation of the tumor from the postoperative scar in 6 patients, exact anatomical location in 3 patients, and both in 2 patients. CONCLUSIONS: FI has a potential clinical value in the treatment of suspected local recurrence of rectal cancer.

Adenocarcinoma↗

PubMed2005

Tumor response assessment is more robust with sequential CT scanning than external caliper measurements.

RATIONALE AND OBJECTIVES: Measurements of tumor size are important in assessing response to cancer therapies. To date, preclinical studies of drug development have relied on direct caliper-based measurements of tumor size. We investigated the feasibility of using a human positron emission tomographic (PET)/computed tomographic (CT) scanner to assess tumor size before and after chemotherapy and compared this approach with caliper measurements. MATERIALS AND METHODS: Fourteen rats with rat mammary tumor underwent high-resolution CT using a PET/CT scanner before and after chemotherapy, and tumor volumes were measured independently by two observers using calipers and CT images. RESULTS: Tumor response could be detected after 1 day of treatment by means of CT imaging, but was not significant until 2 days or later by means of caliper measures because of their greater variability. Independent measurements of tumor size correlated well with one another by means of CT, but correlated less by means of calipers. CONCLUSION: Tumor size measurements by means of CT from PET/CT were more reliable than caliper measurements because of their smaller variance, allowing earlier assessment of response. It is suggested that CT imaging-based methods of assessing tumor response replace traditional caliper-based measurements, much as CT has become a standard for assessing tumor response in humans.

Animals↗

PubMed2005

Normal FDG distribution patterns in the head and neck: PET/CT evaluation.

PURPOSE: To retrospectively evaluate the distribution of fluorine 18 fluorodeoxyglucose (FDG) in the head and neck region with combined positron emission tomography-computed tomography (PET/CT) in patients with no known abnormality in this region. MATERIALS AND METHODS: The institutional review board allowed a retrospective review of PET/CT images obtained in 78 patients with non-head and neck cancer and waived the requirement for informed consent. The accumulation of FDG in 11 normal head and neck structures was visually and quantitatively assessed retrospectively. Positive rate percentage (PRP) was defined as the sum of the percentages of patients with grade 2 and grade 3 tracer uptake intensity. Standardized uptake values (SUVs) were calculated for quantitative analysis. Mean SUVs were compared between the male and female patients by using the unpaired t test, and the correlation between FDG uptake and patient age was assessed by using the Pearson correlation coefficient test. RESULTS: Intense tracer uptake was usually seen in the palatine tonsils (PRP, 98%; mean SUV, 3.48), soft palate (PRP, 96%; mean SUV, 3.13), and lingual tonsils (PRP, 96%; mean SUV, 3.11). In the inferior concha (PRP, 4%; mean SUV, 1.56), thyroid gland (PRP, 3%; mean SUV, 1.31), and tongue (PRP, 1%; mean SUV, 1.39), uptake was typically minimal. FDG accumulation was variable in the sublingual glands (PRP, 72%; mean SUV, 2.93), spinal cord (PRP, 64%; mean SUV, 2.12), submandibular glands (PRP, 53%; mean SUV, 2.11), parotid glands (PRP, 51%; mean SUV, 1.90), and vocal cords (PRP, 19%; mean SUV, 1.77). The mean normal-tissue SUV in the soft palate was higher in male than in female patients (P <.01). A negative correlation between age and physiologic FDG uptake was seen in the palatine tonsils (r=-0.51, P <.001) and sublingual glands (r=-0.70, P <.001). CONCLUSION: Intense FDG uptake was usually observed in the palatine tonsils, lingual tonsils, and soft palate, whereas uptake in the major salivary glands was variable.

Adolescent↗

PubMed2005

CT appearance of bone metastases detected with FDG PET as part of the same PET/CT examination.

PURPOSE: To retrospectively evaluate lesion findings at computed tomography (CT) performed as part of a combined positron emission tomography (PET)/CT examination in patients suspected of having metastatic bone lesions-lesions that were detected with fluorine 18 fluorodeoxyglucose (FDG) PET as part of the same examination-and to correlate the CT and FDG PET findings. MATERIALS AND METHODS: This HIPAA-compliant study had institutional review board approval, and the need for patient informed consent was waived. Three hundred fifty-nine consecutive patients (191 male patients, 168 female patients; mean age, 56.9 years; age range, 8-92 years) underwent PET/CT. PET images were first reviewed by nuclear medicine physicians who had no clinical information regarding the presence or absence of bone metastasis by using a five-point grading system (0, a lesion was definitely negative for metastasis; 1, a lesion was probably negative; 2, a lesion was equivocal; 3, a lesion was probably positive; and 4, a lesion was definitely positive). For lesions assigned a grade of 3 or 4 at PET, CT characteristics such as the presence or absence of morphologic changes or accompanying findings (including bone destruction) were assessed by radiologists on the CT images obtained during the same imaging session. RESULTS: One hundred seventy-nine lesions in 55 patients were considered to be probable or definite bone metastases at PET. One hundred thirty-three of these lesions in 33 patients were clinically confirmed to be bone metastases at follow-up and/or histopathologic examination. CT revealed osteolytic changes in 41 (31%) and osteoblastic changes in 21 (16%) of the 133 lesions, but no or nonspecific changes were seen at CT in 49 (37%) and 22 lesions (17%), respectively. Of the 179 lesions suspected at PET, 46 ultimately proved to be nonosseous or false-positive for bone metastasis. Of these 46 lesions, 38 were not located in the bone but in adjacent tissues such as the pleura. CONCLUSION: CT images obtained as part of PET/CT scanning were useful in yielding the precise location of bone lesions and thus helping avoid misdiagnosis of bone metastasis; however, CT revealed morphologic changes in only half of the lesions assigned a grade of 3 or 4 at PET.

Adolescent↗

PubMed2005

Direct comparison of FDG PET and CT findings in patients with lymphoma: initial experience.

PURPOSE: To retrospectively compare fluorine 18 fluorodeoxyglucose (FDG) positron emission tomographic (PET) and computed tomographic (CT) findings at the same anatomic locations in patients with lymphoma by using a combined PET/CT scanner and to analyze the lesions on metabolic and anatomic bases to evaluate causes of discrepant findings between the two modalities. MATERIALS AND METHODS: The institutional review board allowed an exempt retrospective review of cancer PET database, and informed consent was waived. The study was HIPAA compliant. Fifty-three patients with lymphoma (20 Hodgkin and 33 non-Hodgkin; mean age, 43 years; range, 12-83 years) who underwent FDG PET/CT were included. The PET and CT images were interpreted by two nuclear medicine physicians and one radiologist, respectively, blinded to the other imaging findings. Concordant PET and CT findings were regarded as positive or negative for lymphoma. The site with discordant findings was defined as positive for disease if it was accompanied by other PET- and CT-positive sites in the same patient or was confirmed clinically (histologic examination or progressive disease). Staging results were also compared by one nuclear medicine physician. RESULTS: Of a total of 1537 anatomic sites in 53 patients, 48 had discordant findings between PET and CT. Forty (83%) of the 48 sites had correct PET findings (31 positive, nine negative), five had correct CT findings, and three were unresolved. The 31 PET-positive and CT-negative sites accounted for 23% of all 134 true-positive PET sites. PET provided accurate staging in an incremental nine (17%, upstaging in four and downstaging in five) of 53 patients in whom CT staging was incorrect. CT provided correct upstaging in two patients. CONCLUSION: FDG PET/CT as a combined modality may contribute substantially to lesion characterization and staging in patients with lymphoma.

Adolescent↗

PubMed2004

Bacteriolytic therapy can generate a potent immune response against experimental tumors.

When spores of the anaerobic bacterium Clostridium novyi-NT are systemically injected into animals, they germinate exclusively within the hypoxic regions of cancers. The germinated bacteria destroy adjacent tumor cells but spare a rim of well oxygenated tumor cells that subsequently expand. Surprisingly, we found that approximately 30% of mice treated with such spores were cured of their cancers despite the viable tumor rim initially remaining after spore germination. The mechanism underlying this effect was shown to be immune-mediated, because cured animals rejected a subsequent challenge of the same tumor. Similar effects were observed in rabbits with intrahepatic tumors. It was particularly notable that the induced immune response, when combined with the bacteriolytic effects of C. novyi-NT, could eradicate large established tumors.

Adoptive Transfer↗

PubMed2004

PET/CT: artifacts caused by bowel motion.

BACKGROUND AND AIM: In a combined positron emission tomography (PET) and computed tomography (CT) system, the CT images can be used for attenuation correction as well as for image fusion. However, quantitative and qualitative differences have been reported between CT based attenuation corrected PET and conventional transmission scan corrected PET images. The purpose of this study was to investigate potential differences in PET/CT caused by attenuation differences in bowel due to motion. METHODS: Twelve patients had PET/CT scans performed using 68Ge transmission and CT attenuation correction methods. Three emission imaging datasets were generated including CT corrected PET, Ge corrected PET, and the difference images (CT corrected PET minus Ge corrected PET). PET difference images were used to identify regions of mismatch and to quantify possible discordance between images by using standardized uptake values (SUVs). Using the Ge corrected PET as the standard, differences in emission images were classified as an overestimation (pattern A) or an underestimation (pattern B) in these difference images. RESULTS: One hundred and twenty-three mismatched areas were identified. Among them, overestimated areas in CT corrected image were detected in 36 regions (pattern A), while underestimated areas were evaluated in the remaining 87 regions (pattern B). The mean value of the difference in pattern A (mean +/- standard deviation = 0.84 +/- 0.44) was slightly higher than that in pattern B (0.60 +/- 0.23), and statistically significant. Six of 36 regions in pattern A had an SUV of greater than 2.5 in CT corrected PET but less than 2.5 in Ge corrected PET; two of 87 regions with pattern B demonstrated an SUV greater than 2.5 in Ge corrected PET and less than 2.5 in CT corrected PET. CONCLUSION: Physiological bowel motion may result in attenuation differences and subsequent differences in SUVs. Overestimation of fluorodeoxyglucose uptake should not be misinterpreted as disease.

Abdominal Neoplasms↗

PubMed2004

Intense (18)F-FDG uptake in brown fat can be reduced pharmacologically.

UNLABELLED: Physiologic (18)F-FDG uptake in areas of supraclavicular fat in humans ("USA-Fat") has recently been recognized as (18)F-FDG uptake in apparent brown adipose tissue (BAT) using fused PET/CT technology. In this study, we evaluated (18)F-FDG uptake in BAT of rats to determine whether pharmacologic or physiologic interventions affect the uptake, knowing that BAT has a high density of adrenergic innervation. METHODS: Seven- to 8-wk-old female Lewis rats receiving intravenous (18)F-FDG injections were examined under various conditions to evaluate (18)F-FDG biodistribution into interscapular BAT and major organs. In series 1, rats were given ketamine-based anesthesia or were exposed to cold (4 degrees C for 4 h) to determine whether these interventions increased (18)F-FDG uptake in BAT. In series 2, anesthetized rats (ketamine-based anesthesia) were given propranolol, reserpine, or diazepam intraperitoneally before (18)F-FDG injection to determine whether the drug reduced (18)F-FDG uptake in BAT. The control and treated groups in series 2 were also evaluated with (18)F-FDG PET/CT imaging. RESULTS: In series 1, anesthesia or exposure to cold increased (18)F-FDG uptake in BAT to levels 14-fold and 4.9-fold, respectively, greater than the control nonstimulated values. BAT uptake was high, comparable to that in the brain. In series 2, (18)F-FDG uptake in BAT was significantly decreased to less than 30% of the control level after propranolol or reserpine (P < 0.05). Diazepam did not significantly decrease (18)F-FDG uptake in BAT. (18)F-FDG PET/CT findings reflected these biodistribution data: The control and diazepam groups exhibited intense (18)F-FDG uptake in BAT, whereas the propranolol and reserpine groups showed only faint to mild (18)F-FDG uptake in BAT. Among several organs whose (18)F-FDG uptake was affected after predosing drugs, the heart exhibited considerable decreases in tracer uptake with propranolol or reserpine. CONCLUSION: This rodent study demonstrated that BAT can exhibit high (18)F-FDG uptake under stimulated conditions including exposure to cold and that propranolol or reserpine treatment can remarkably reduce the high (18)F-FDG uptake in BAT. The effect of these drugs on (18)F-FDG uptake in human BAT, as well as on tracer accumulation in other organs, should carefully be evaluated clinically to minimize the USA-Fat artifact.

Acepromazine↗

PubMed2003

Fluorodeoxyglucose uptake in the aortic wall at PET/CT: possible finding for active atherosclerosis.

PURPOSE: To evaluate fluorine 18 fluorodeoxyglucose (FDG) uptake in the thoracic aortic wall at combined positron emission tomography (PET)/computed tomography (CT) and compare uptake with aortic wall calcification. MATERIALS AND METHODS: Records of 85 consecutive cancer patients who underwent FDG PET/CT were evaluated retrospectively. One hour after FDG injection, CT followed by PET was performed from ear to middle of the thigh. CT, PET, and fused PET/CT images were generated. FDG uptake and calcification were evaluated visually and semiquantitatively. FDG uptake was graded according to intensity; calcification, according to thickness. Unpaired t test was used for comparison of patient age with and without FDG uptake and with and without calcification. The relationship between the score (sum of grades along all aortic segments) of positive FDG uptake and calcification and patient age was analyzed with Spearman rank correlation. Comparison of frequency of FDG uptake and calcification with age, sex, risk factors for cardiovascular disease (CVD), or history of CVD was performed with chi2 analysis. RESULTS: Fifty patients had at least one area of FDG uptake in thoracic aortic wall, 14 of whom showed focal FDG uptake. Intermediate to intense FDG uptake tended to be observed in the descending aorta. Forty-five patients had at least one measurable aortic calcification. Thick calcification was observed most often at the aortic arch. Twelve patients had 13 uptake areas at the calcification site. Patients with positive findings were on average older (P <.05 for both increased uptake and calcification); the older patient group had higher frequency of both aortic wall uptake (P <.005) and calcification (P <.001). The calcification score correlated with age (rho = 0.60, P <.001) but the FDG uptake score did not. Women, patients with hyperlipidemia, and patients with history of CVD tended to show increased FDG uptake (P =.073,.080, and.068, respectively), whereas patients with diabetes had significantly more calcifications (P <.05). CONCLUSION: PET/CT depicted FDG uptake commonly in the thoracic aortic wall. The FDG uptake site was mostly distinct from the calcification site and may possibly be located in areas of metabolic activity of atherosclerotic changes.

Adolescent↗

PubMed2003

Initial experience in small animal tumor imaging with a clinical positron emission tomography/computed tomography scanner using 2-[F-18]fluoro-2-deoxy-D-glucose.

The feasibility of small animal imaging using a clinical positron emission tomography/computed tomography (PET/CT) scanner with [F-18]-fluoro-2-deoxy-D-glucose (FDG) was evaluated. As tumor-bearing small animal models, rabbits with VX-2 liver tumors, rats with mammary tumors on the back, and mice with LS174T human colon tumor xenografts were prepared. Two-dimensional PET, CT, and fused PET/CT images were obtained and reconstructed with a combined PET/CT system using a conventional protocol for humans and dedicated high-resolution mode protocols specialized for each species. Estimated radioactivity concentrations in tumors and normal organs determined noninvasively on FDG-PET/CT were compared with the actual tissue radioactivity levels determined from gamma-counting after vivisection in rats. In addition, recovery-corrected radioactivity concentrations were calculated and evaluated using the tumor/normal organ sizes measured on CT. Tumors in rabbits and rats were clearly visualized by FDG-PET/CT in the dedicated protocols, and images were considered suitable for research purposes. With the aid of thin-slice CT-mapping images, FDG uptake was correctly localized in the viable tumor regions. In mice, increased FDG uptake in tumors with varying activity levels was observed, but detailed anatomical information was not optimally provided from the images, even using specialized protocols. The estimated radioactivity concentrations of tumors and normal organs were close to the actual radioactivity concentrations obtained by gamma-counting (r = 0.97, P < 0.001, the estimated/actual slope: 1) when recovery correction was applied using the sample sizes measured on CT. FDG-PET/CT imaging with a modern clinical scanner was demonstrated to be feasible, of excellent quality, and quite quantitatively accurate for research in rabbits or rats with tumors of appropriate size (>2 cm without recovery correction and >1 cm with recovery correction). Evaluation of FDG uptake within a tumor was possible with the aid of CT images. Dedicated small animal PET/CT scanner would be better suited for evaluating tumor-bearing mice and likely could enhance imaging smaller tumors in rabbits or rats. Although it has limitations, small animal imaging with a clinical PET/CT scanner may be quite adequate for sequential noninvasive imaging in oncology research because the CT is of high resolution, allowing for localization of PET findings and for more precise noninvasive estimation of radioactivity concentration through partial volume corrections.

Animals↗

PubMed2003

Accuracy of image fusion of normal upper abdominal organs visualized with PET/CT.

Although PET/CT scanners have the potential for precise fused registration of structures visualized on both PET and CT, physiological motion during the acquisition of both studies may alter the appearance of organ shape, size or location. The degree of possible mismatch in abdominal organ size and position between PET and CT has not been evaluated. The aim of this study was to assess the consistency in location and measured size of upper abdominal organs with PET and CT using a combined PET/CT system. Forty-six consecutive inpatients who underwent clinical PET/CT scans for suspected cancer were evaluated. CT and PET images attenuation corrected by both CT and germanium-68 transmission scans were obtained, and we separately determined the location of the top and bottom (height), anterior and posterior margins (thickness), and right and left margins (width) for each organ, including liver, spleen, and bilateral kidneys, using CT and both sets of PET images. Differences between the two modalities in terms of location and measured organ size were investigated. In the upper margin of the liver and lower margin of the spleen, more than 10% of the cases showed a larger discrepancy (>20 mm) between CT-based and Ge-corrected PET-based measurements, although the differences in the positions of the edges were less than 10 mm in most cases. The center of the liver tended to be located cephalad and to the right of the body, and that of the spleen tended to be cephalad and posterior on PET, as compared with CT. Moreover, the center of both kidneys tended to be seen cephalad, posterior, and to the right on PET. The liver appeared slightly larger on PET than CT in thickness (CT vs CT-corrected PET vs Ge-corrected PET = 156 mm vs 162 mm vs 162 mm) and width (186 mm vs 189 mm vs 188 mm). By contrast, the spleen appeared slightly smaller on PET than CT in height (84 mm vs 77 mm vs 80 mm) and width (85 mm vs 81 mm vs 80 mm). A similar tendency was observed in the left kidney (105 mm vs 100 mm vs 99 mm in height, and 64 mm vs 59 mm vs 58 mm in width) and the right kidney (99 mm vs 93 mm vs 93 mm in height, and 64 mm vs 59 mm vs 60 mm in width). These differences between the two modalities were statistically significant ( P<0.05). In conclusion, minor mismatches in location and organ size were found to exist between CT and PET images, in part due to physiological motion. Although these differences could potentially affect the quality of the image registrations, they were generally of a modest nature.

Abdomen↗

PubMed2002

FDG metabolism and uptake versus blood flow in women with untreated primary breast cancers.

The aim of this study was to determine the relationship between tumor blood flow and glucose utilization in women with untreated primary breast carcinomas. Noninvasive determinations of blood flow and glucose utilization with positron emission tomography (PET) were performed in 101 regions of tumor from nine women with untreated primary breast carcinoma. [(15)O]H(2)O PET scans of tumor blood flow were compared with fluorine-18 fluoro-2-deoxy- D-glucose (FDG) PET scans of tumor glucose metabolism. Modeling of multiple parameters was undertaken and flow and glucose utilization compared. Mean whole-tumor blood flow was 14.9 ml dl(-1) min(-1), but ranged from 7.6 to 29.2 ml dl(-1) min(-1). Mean whole-tumor standardized uptake value corrected for lean body mass, SUV-lean (50-60 min), was 2.32+/-0.19 while mean K(i) was 1.2 ml dl(-1) min(-1) for FDG. SUV-lean and blood flow were strongly correlated (r=0.82, P=0.007) as were K(1) for FDG and flow (r=0.84, P=0.004). In these women with untreated breast cancers, FDG uptake (SUV-lean) and tumor blood flow are strongly correlated. The slope of FDG uptake versus blood flow appears higher at low flow rates, suggesting the possible presence of areas of tumor hypoxia.

Adult↗

PubMed2002

Impact of body habitus on quantitative and qualitative image quality in whole-body FDG-PET.

Obtaining consistent high image quality is desirable for clinical positron emission tomography (PET). Body morphology may impact image quality. The purpose of this study was to define the average and the range of body sizes in patients undergoing tumor PET studies in our center and to determine how the body habitus affects the statistical and visual quality of PET images. Height, weight, body surface area (BSA), and body mass index (BMI) were determined in 101 male and 101 female patients (group 1) referred for clinical PET. The summed total counts from three consecutive transaxial slices on non-attenuation-corrected (NAC) 2D fluorine-18 fluorodeoxyglucose (FDG) PET images, which included the largest liver section and no lesions, were determined and compared with body morphology and injected doses (ID) in a representative group of 30 male and 30 female patients (group 2) spanning a range of body morphologies. The visual quality of images was also evaluated using a scoring system by three readers. The average height, weight, and BSA were greater in male than in female patients, but the average BMI was not different between them in group 1. The largest value of weight or BMI was more than four times the smallest value in female patients. The total true counts were best correlated with ID/weight (mCi/kg) in group 2 ( r=0.929, P<0.0001). Intermediate to high total counts (930,000 or more) corresponded to ID/weight of 0.22 or higher. The average visual score was positively correlated with the total counts (rho=0.63, P<0.0001) and with ID/weight (rho=0.68, P<0.0001) on NAC images. The image quality in 22 (84.6%) of 26 patients with intermediate to high total counts was adequate to good, whereas that in 21 (61.8%) of 34 patients with lower total counts was suboptimal. A wide variety of body morphologies was observed in patients referred for clinical FDG-PET tumor studies in our center. The total counts and average image visual score were negatively correlated with weight. Counts in heavy patients were as low as one-fourth those in light patients. Adjusting injected FDG dose in each patient on the basis of body weight may be more appropriate to achieve consistent PET image quality than giving a fixed injected FDG dose.

Body Mass Index↗

PubMed2002

Evaluation of MS-209, a novel multidrug-resistance-reversing agent, in tumour-bearing mice by technetium-99m-MIBI imaging.

MS-209 is a newly synthesised multidrug-resistance (MDR)-reversing agent with few side-effects. In this study, we evaluated the effect of MS-209 on P-glycoprotein (Pgp)-positive tumours in mice by means of technetium-99m methoxyisobutylisonitrile (MIBI) imaging. Mice received Pgp-negative KB-3-1 or Pgp-positive KB-C1 cell xenografts. KB-3-1-bearing mice were administered 0 or 100 mg/kg of MS-209 (groups S0 and S100, respectively), and KB-C1-bearing mice 0, 50, 100 or 200 mg/kg (groups R0, R50, R100 and R200, respectively), 30 min before imaging studies. Dynamic 99mTc-MIBI images were acquired for 30 min, followed by biodistribution studies. Washout of 99mTc-MIBI from the tumours was faster in group R0 than in group S0 on visual analysis, and the washout half-time estimated by region of interest analysis was shorter in group R0 than in group S0. Biodistribution studies revealed that 99mTc-MIBI accumulation in tumours (expressed as %ID/g) was also lower in group R0 than in group S0. MS-209 delayed the 99mTc-MIBI washout from KB-C1 tumours. Washout half-time was longer in groups R50, R100 and R200 than in group R0. A higher %ID/g was observed in groups R100 and R200 than in group R0. In KB-3-1 tumours, MS-209 had no effect on the washout half-time or the %ID/g. This study demonstrated that MS-209 increases the 99mTc-MIBI accumulation in Pgp-positive tumours. The MDR-reversing effect of MS-209 could be effectively evaluated with 99mTc-MIBI visually and non-invasively in vivo. 99mTc-MIBI imaging with MS-209 prior to chemotherapy should contribute significantly to the treatment strategy in patients with multidrug-resistant tumours.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2002

Clinical relevance of fusion images using (18)F-2-fluoro-2-deoxy-D-glucose positron emission tomography in local recurrence of rectal cancer.

Local recurrence of rectal cancer is a critical issue. Anatomical images, such as computed tomography (CT) or magnetic resonance imaging (MRI), are sometimes insufficient for preoperative evaluation. A useful modality for diagnosis of local recurrence of rectal cancer is (18)F-2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET), but it does not give adequate information about anatomy. To utilize the advantages of these techniques, this study was done to validate the accuracy of using fused images and their usefulness in the decision making for surgical intervention of local recurrence of rectal cancer by directly comparing the fused images with resected specimens. PET and CT/MRI were performed for patients suspected of local recurrence of rectal cancer (n=4). PET image data were re-calculated to fit CT/MRI images and manually superimposed on the anatomical images. Fusion images were compared with resected specimens. Radical operation was carried out for three patients. Fusion images provided information on precise tumor location, and extent of tumor invasion as well as the diagnosis of tumor recurrence. All patients underwent curative operation with negative surgical margins, and the information provided by the fusion images was confirmed by comparison with resected specimens. In all cases, preoperative evaluation of tumor recurrence with fusion images provided more useful clinical information for the management of patients than the anatomical images alone. PET images, when combined with MRI or CT, may prove to be a useful adjunct in the management of patients being evaluated for resection of local recurrence of rectal cancer.

Aged↗