Biomedical subjects

K Kletter

Publications and source records attributed to K Kletter.

At least 19 recordsLinked to original sources

PubMed2006

18F-Fluoro-deoxy-glucose positron emission tomography in lymphoma of mucosa-associated lymphoid tissue: histology makes the difference.

BACKGROUND: The usefulness of 2-[fluorine-18]fluoro-2-deoxy-D-glucose Positron emission tomography (18F-FDG-PET) in lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is still a matter of debate, and conflicting results have been reported. We have evaluated whether the histological feature of plasmacytic differentiation (PD) might explain the heterogeneous behavior of MALT lymphoma regarding 18F-FDG uptake. PATIENTS AND METHODS: A total of 35 patients with a diagnosis of MALT lymphoma referred to our PET unit were studied. Whole-body 18F-FDG-PET scans were carried out on a General Electrics advanced PET scanner 40 min after i.v. injection of 300-380 MBq 18F-FDG. Images were reconstructed iteratively. In areas with focally elevated FDG uptake, standard uptake values (SUVs) were calculated. RESULTS: A total of 19 patients had MALT lymphoma with plasmacytic differentiation (pMALT), while MALT lymphoma without plasmacytic features was diagnosed in 16 patients. Sixteen of 19 patients with PD showed significant 18F-FDG uptake in involved sites (SUV: 3.5-11.7). By contrast, 13 of 16 patients with normal MALT lymphoma showed a false-negative 18F-FDG-PET result. Two of these patients disclosed no tracer uptake in the majority of involved sites apart from one single lesions, while three had a true-positive 18F-FDG-PET scan (SUV: 3.4-6.0). CONCLUSIONS: 18F-FDG-PET visualizes pMALT in a high proportion of patients, whereas FDG-PET results are significantly less reliable in typical MALT (P = 0.001). This finding may partly account for the heterogeneous results of 18F-FDG-PET-studies in MALT lymphoma.

Adult↗

PubMed2006

18F-fluoro-deoxy-glucose positron emission tomography (18F-FDG-PET) visualizes follicular lymphoma irrespective of grading.

BACKGROUND: 18F-fluoro-deoxy-glucose positron emission tomography (18F-FDG-PET) has become a routine measure for staging and follow-up of patients with aggressive lymphoma. By contrast, its usefulness to visualize indolent lymphomas characterized by a lower cellular turnover has not clearly been defined. We have investigated accuracy and clinical usefulness of 18F-FDG-PET in patients with follicular lymphoma (FL). PATIENTS AND METHODS: A total of 64 patients with FL WHO grade I - III (48, 5, and 11 patients) were imaged at our institution to assess the value of 18F-FDG-PET for imaging of FL of different gradings. A total of 115 scans (48 before therapy and 67 for response assessment after treatment) were performed, and findings were compared to conventional staging including CT-scan of thorax and abdomen, sonography of lymph nodes and bone marrow biopsy. RESULTS: Overall, 18F-FDG-PET had a sensitivity of 98%, a specificity of 94%, a positive predictive value of 95% and a negative predictive value of 98%. These results were significantly more accurate (P = 0.023) than the conventional radiology studies. There was no significant difference (P = 0.093) in the accuracy between patients with indolent (WHO grade I and II) versus aggressive FL (WHO grade III). CONCLUSION: 18F-FDG-PET scan is a reliable method for staging and follow up of patients with nodal FL irrespective of tumor grading.

Adult↗

PubMed2006

5-aminosalicylic acid release from a new controlled-release mesalazine formulation during gastrointestinal transit in healthy volunteers.

BACKGROUND: Mesalazine (5-aminosalicylic acid, 5-ASA) containing formulations represent a cornerstone in the treatment of inflammatory bowel diseases. A novel formulation with an Eudragit L/S mixture coating has been developed to provide selective release of 5-ASA to the ileo-caecal region and the colon. AIM: To determine the release of 5-ASA during the gastrointestinal transit. METHODS: A single oral dose of mesalazine EC 500 mg gastroresistant tablets (Asamax) was administered to eight healthy male volunteers. Gastrointestinal transit and tablet disintegration were monitored by scintigraphy. 5-ASA release was verified by assessing plasma pharmacokinetics. RESULTS: Initial tablet disintegration was observed 5.65 +/- 0.86 h after dosing, corresponding to the detection of 5-ASA in plasma. This occurred in the ileo-caecal region in three subjects and the ascending colon in the remaining five. The relative percentage of 5-ASA absorption was more pronounced in the ascending colon (41 +/- 27.4%) than the ileo-caecal region (6.6 +/- 9.2%). CONCLUSION: This mesalazine EC gastroresistant tablets release locally active 5-ASA specifically in the ileo-caecal region and the ascending colon.

Administration, Oral↗

PubMed2006

Gastrointestinal transit, release and plasma pharmacokinetics of a new oral budesonide formulation.

AIMS: The aims of the study were to: (1) evaluate the gastrointestinal transit, release and absorption of budesonide from tablets with a new multimatrix formulation (MMX) designed to release the drug throughout the whole colon, and (2) assess the influence of food on budesonide bioavailability. METHODS: Two phase I studies, each comprising 12 healthy males, were performed. Gastrointestinal transit of (153)Sm-labelled tablets containing 9 mg budesonide was evaluated by means of pharmaco-scintigraphy. The effect of food was tested by comparing plasma pharmacokinetics after intake of a high fat and high calorie breakfast with fasting controls. RESULTS: (153)Sm-labelled tablets reached the ascending colon after a mean +/- SD 9.8 +/- 6.9 h. Initial tablet disintegration was observed in the ileum in 42% and the ascending and transverse colon in 33% of subjects. Ninety-six per cent of the dose was absorbed into the systemic circulation during passage through the whole colon including the sigmoid. Food significantly decreased C(max) values from 1429 +/- 1014 to 1040 +/- 601 pg mL(-1) (P = 0.028) and AUC values from 14 814 +/- 11 254 to 13 486 +/- 9369 pg h(-1) mL(-1) (P = 0.008). Mean residence time and t(max) increased by 12-29%. There was no drug accumulation after 1 week of once daily oral administration of budesomide. CONCLUSIONS: MMX-budesonide tablets appear suitable for targeted colonic drug delivery. Transit parameters and low systemic bioavailability warrant further studies with the new formulation.

Absorption↗

PubMed2006

Myocardial perfusion in patients with typical chest pain and normal angiogram.

BACKGROUND: Approximately 10-30% of patients with typical chest pain present normal epicardial coronaries. In a proportion of these patients, angina is attributed to microvascular dysfunction. Previous studies investigating whether angina is the result of abnormal resting or stress perfusion are controversial but limited by varying inclusion criteria. Therefore, we investigated whether microvascular dysfunction in these patients is associated with perfusion abnormalities at rest or at stress. PATIENTS AND METHODS: In 58 patients (39 female, 19 male, mean age 58+/-10 years) with angina and normal angiogram as well as 10 control patients with atypical chest pain and normal coronaries (six female, four male, mean age 53+/-11 years) myocardial blood flow (MBF) was measured at rest and under dipyridamole using 13N-ammonia PET. Resting MBF and coronary flow reserve (CFR) as the ratio of hyperaemic to resting MBF were corrected for rate-pressure-product (RPP): normalized resting MBF (MBFn)=MBFx10,000/RPP and CFRn=CFRxRPP/10,000. RESULTS: Sixteen/58 patients had a normal CFRn (=2.5; group I; CFRn: 3.1+/-0.88); the same as the controls (CFRn: 3.3+/-0.74). Forty-two/58 patients presented a reduced CFRn (group II; CFRn: 1.78+/-0.57). Group II had both a higher MBFn (group II: 1.30+/-0.33 vs. Group I: 1.03+/-0.26; P<0.05 and vs. controls: 1.07+/-0.19; P<0.01) and a lower hyperaemic MBF (group II: 2.25+/-0.76 mL g-1 min-1 vs. Group I: 3.07+/-0.78 mL g-1 min-1; P<0.001 and vs. controls: 3.41+/-0.94 mL g-1 min-1; P<0.0001). CONCLUSION: Impaired CFRn in patients with typical angina and normal angiogram is owing to both an increased resting and reduced hyperaemic MBF. Therefore, PET represents a prerequisite for further studies to optimize treatment in individuals with anginal pain and normal coronary angiogram.

Adult↗

PubMed2006

FDG gamma camera PET equipped with one inch crystal and XCT. Assessment of myocardial viability.

UNLABELLED: Metabolic imaging with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) is actually considered as the best method to detect and quantitatively assess myocardial tissue viability. The aim of this study was to investigate the accuracy of FDG gamma camera positron emission tomography (GCPET) imaging equipped with one inch NaI crystals in comparison to FDG dedicated PET (dPET) imaging as a "gold standard" in phantom and clinical studies. PATIENTS, METHODS: Nineteen patients with coronary artery disease (CAD) underwent both imaging modalities. Phantom and clinical GCPET imaging were performed with a dual-headed, coincidence based gamma camera equipped with 1 inch thick NaI crystals and an x-ray tube (XCT) for attenuation correction (AC), as well as with a dedicated PET scanner with AC. (99m)Tc tetrofosmin single-photon emission tomography (SPET) studies were performed for assessment of myocardial perfusion, with AC. RESULTS: Phantom studies showed a significant relation in segmental activity between FDG imaging with AC using GCPET and dPET (r = 0.91, p < 0.001). In clinical studies with AC correlation coefficients of mean segmental FDG uptake and regional defect size were r = 0.87 (p < 0.0001) and r = 0.83 (p < 0.0001), respectively. In regional analysis close agreement was even found in the most attenuated regions of the heart if AC was used in GCPET imaging. The overall agreement for detection of viable myocardium was 81% between FDG-dPET (AC) and FDG-GCPET (AC) and 74% between FDG-dPET (AC) and FDG-GCPET (NC). CONCLUSION: This study suggests that the assessment of myocardial metabolism by means of FDG is feasible with a coincidence based gamma camera equipped with 1 inch thick NaI crystals if AC is performed. The results reveal a close concordance and agreement between FDG-dPET (AC) and FDG-GCPET (AC) as compared to FDG-GCPET (NC).

Aged↗

PubMed2006

Attenuation correction for myocardial perfusion imaging. A comparison between SPECT and PET imaging by polar map analysis.

AIM: We investigated the impact of photon attenuation in myocardial perfusion imaging with SPECT and PET in patients with coronary artery disease. In fact, the regional tracer distribution can be quantitatively assessed by polar map analysis if the effects of photon attenuation are accounted for. PET imaging permits accurate measurement of and correction for photon attenuation, whereas results of attenuation correction in SPECT imaging have been inconsistent. PATIENTS, METHODS: We compared photon attenuation in resting perfusion imaging studies with SPECT ((99m)Tc-sestamibi) and PET ((13)N-ammonia) from 21 patients. Transaxial images were reconstructed with and without attenuation correction and reoriented into short axis images. Polar map analysis was utilized to generate regional tracer uptake in six anatomical segments. RESULTS: Average segmental photon attenuation calculated as the ratio of counts in corrected and uncorrected images was 7.2 +/- 1.4 in SPECT and 14.0 +/- 3.1 in PET imaging (p < 0.01). This attenuation factor was significantly related to body mass index for both methods (p < 0.001). While attenuation correction for SPECT imaging did compensate for attenuation effects in the inferior wall (from -15% to +6% vs. PET), relative tracer uptake in the anterior wall in SPECT images was significantly reduced after attenuation correction (from -2% to -18% vs. PET, p < 0.01). CONCLUSION: Differential effects of attenuation correction for myocardial SPECT perfusion imaging need to be considered when algorithms designed to compensate effects of photon attenuation in SPECT imaging are employed in clinical practice.

Aged↗

PubMed2006

13N-ammonia rest/stress PET: folic acid improves global coronary vasoreactivity in coronary artery disease patients with normal or elevated homocysteine levels.

AIM: Hyperhomocysteinaemia (Hhcy) is known to be an independent risk factor for vascular disease. Coronary flow reserve (CFR) measured by positron emission tomography (PET) is a sensitive method to monitor the effects of pharmacologic interventions in Hhcy. We assessed coronary vascular reactivity by PET in patients with coronary artery disease (CAD) dependent on their homocysteine (Hcy) levels before and under high dose folic acid supplementation therapy (FAST). PATIENTS, METHODS: Twelve patients with CAD underwent rest/adenosine (13) N-ammonia PET for quantification of myocardial blood flow (MBF) and CFR before and after nine weeks FAST (10 mg/day). RESULTS: Folate levels increased from 21 +/- 6 to 210 +/- 34 microg/l (+900%, p < 0.0001) while Hcy levels decreased from 12.1 +/- 3.6 to 9.1 +/- 3.1 micromol/l ( - 25%; p < 0.01). Global resting MBF remained nearly unchanged after FAST, while stress MBF (from 2.61 +/- 0.93 to 3.25 +/- 1.15 ml/g/min; p = 0.05) and CFR (from 3.00 +/- 0.76 to 3.72 +/- 0.93 ml/g/min; p < 0.05; +24%) significantly increased in patients with normal and elevated Hcy levels (cut off 12 micromol/l). An inverse relation was found between Hcy and CFR (R = - 0.53; p = 0.08) and between Hcy and MBF at rest (R = - 0.62; p < 0.05) at baseline conditions, not persisting after FAST. CONCLUSION: Coronary vascular reactivity can be improved by FAST in patients with CAD and normal or elevated Hcy levels. FAST might lower an increased cardiovascular risk in CAD patients possibly by mechanisms that are not related to Hcy.

Aged↗

PubMed2005

Colonic spread and serum pharmacokinetics of budesonide foam in patients with mildly to moderately active ulcerative colitis.

BACKGROUND: Local treatment with foams in patients suffering from ulcerative proctitis or proctosigmoiditis is considered a rational treatment option. AIMS: To investigate colonic spread, safety, tolerability and acceptance of a newly developed budesonide foam formulation. METHODS: Twelve patients (four females, eight males) with acute proctosigmoiditis or left-sided ulcerative colitis were rectally administered a single dose of [99Tcm]-labelled budesonide foam (Budenofalk; Dr Falk Pharma GmbH, Freiburg, Germany) containing 2 mg budesonide in 20 mL foam after diagnostic colonoscopy. Thereafter, the colonic spread was assessed by means of gamma-scintigraphy for 6 h. Serum samples were taken simultaneously. RESULTS: Budesonide foam spread with a maximum between 11 and 40 cm, thus reaching the sigmoid colon in all patients. In some patients, the foam even extended into the distal third and the middle of the descending colon with maximum radioactivity at 4 h. Systemic budesonide absorption was rapid and pharmacokinetic data were comparable with published data on marketed budesonide enemas, with mean serum C(max) and AUC(0-8 h) values of 0.8 +/- 0.5 ng/mL and 3.7 +/- 1.9 ng h/mL, respectively. The new formulation was well accepted by all patients, who could retain the foam for at least 4 h. CONCLUSIONS: In the majority of patients, budesonide foam effectively spread up to the left-sided colon and thus qualifies for the local treatment of proctosigmoiditis.

Administration, Rectal↗

PubMed2003

Gastrointestinal transit and release of 5-aminosalicylic acid from 153Sm-labelled mesalazine pellets vs. tablets in male healthy volunteers.

BACKGROUND: Mesalazine (5-aminosalicylic acid)-containing formulations, designed to optimize drug delivery to the ileo-caecal region, represent a cornerstone in the treatment of inflammatory bowel diseases. AIM: : To test, by means of pharmaco-scintigraphy, whether novel mesalazine-containing pellets release 5-aminosalicylic acid in the same target region as mesalazine tablets (Salofalk). METHODS: Fourteen healthy male volunteers received a single dose of either pellets or tablets containing 500 mg of mesalazine and 2 mg of 152Sm2O3 with a 1-week washout period. The gastrointestinal transit of 153Sm, incorporated into the formulations, was followed by gamma-scintigraphy. Mesalazine release was verified by assessing 5-aminosalicylic acid plasma pharmacokinetics. RESULTS: The formulations reached the ileo-caecal target region almost at the same time (3.3 +/- 1 and 3.8 +/- 1 h for pellets and tablets, respectively). Plasma 5-aminosalicylic acid tmax values were comparable and corresponded to the time during which the formulations were located in the target region. Plasma AUC values were significantly lower for pellets, which might be explained by a more prolonged release of 5-aminosalicylic acid. CONCLUSIONS: Novel mesalazine pellets and Salofalk tablets release active 5-aminosalicylic acid in the same target region and pass through the gastrointestinal tract under fasting conditions in healthy volunteers in a comparable time. From a comparison of in vitro dissolution and plasma concentration data, a slower and more prolonged release of 5-aminosalicylic acid from pellets is suggested.

Adult↗

PubMed2003

Gastrointestinal transit and 5-ASA release from a new mesalazine extended-release formulation.

BACKGROUND: Mesalazine (5-aminosalicylic acid, 5-ASA)-containing formulations represent a cornerstone in the treatment of inflammatory bowel diseases. Recently, a new formulation has been developed to provide selective and more homogeneous release of 5-ASA compared to traditional systems. METHODS: In a first study, gastrointestinal transit was followed by gamma-scintigraphy after single-dose application of tablets containing 1200 mg mesalazine to 12 healthy male volunteers. 5-ASA release was verified by the assessment of plasma pharmacokinetics. In a second, 7-day, multiple-dose study, the steady state plasma pharmacokinetics, urinary excretion and safety profile were characterized after twice-daily tablet administration to 12 healthy volunteers. RESULTS: Tablet erosion started after 6.9 +/- 1.1 h in the ascending or transverse colon. Radioactivity spread homogeneously throughout the colon, indicating the sustained release of active 5-ASA. Plasma kinetics indicated an earlier initial absorption of 5-ASA, i.e. during transit of the small intestine and ileum. Mean Cmax values (350.6 +/- 322.6 ng/mL) were observed during location in the ileo-caecal region. The mean relative absorption of 5-ASA was 19.9 +/- 18.2% in the small intestine and ileum and 80.1 +/- 18.2% in the colon. CONCLUSIONS: The administration of the new mesalazine formulation was well tolerated, and 5-ASA was continuously released along the whole colon, a favourable prerequisite for the therapy of distally located inflammatory bowel disease.

Adult↗

PubMed2003

18F-fluoro-deoxy-glucose positron emission tomography (18F-FDG-PET) for assessment of enteropathy-type T cell lymphoma.

BACKGROUND AND AIMS: Enteropathy-type T cell lymphoma (ETCL) represents a relatively rare disease, accounting for less than 1% of non-Hodgkin's lymphomas. ETCL is an aggressive lymphoma which may either present de novo or arise in the context of longstanding or untreated coeliac disease (CD). The aim of this study was to evaluate the potential of 18F-fluoro-deoxy-glucose positron emission tomography (18F-FDG-PET) for imaging of ETCL. Furthermore, we wished to evaluate whether the presence of CD might provide a potential diagnostic obstacle to imaging of lymphoma due to unspecific 18F-FDG uptake and whether accumulation of 18F-FDG within the gut correlates with activity of CD. PATIENTS AND METHODS: We retrospectively analysed patients with ETCL and individuals suffering from CD undergoing 18F-FDG-imaging at our PET unit. Material for histological reassessment by a reference pathologist had to be available for inclusion of patients in the analysis. Whole body 18F-FDG-PET scans were performed 40 minutes following injection of 300-380 MBq of 18F-FDG. Images were reconstructed iteratively. In areas with focally elevated FDG uptake and in case of diffusely elevated intestinal 18F-FDG accumulation, standard uptake values (SUVs) were calculated. RESULTS: During a period of two years, five patients (one male, four female) with a mean age of 56.4 years (range 44-62) with a diagnosis of ETCL underwent 18F-FDG-PET. Four of these patients were imaged before application of cytotoxic treatment while one patient had regular PET scans for follow up. All four patients undergoing pre-therapeutic imaging showed markedly elevated intestinal 18F-FDG uptake, with a maximal SUV of 6.4-8.0 (mean 7.15 (SD 0.82)). The patient imaged following surgery and cytotoxic therapy had no pathologic 18F-FDG uptake which was found to correlate with normal duodenal mucosa, as evidenced by repeated biopsies and conventional imaging methods. During the same time span, 12 patients (five male, seven female) with a mean age of 63.8 years (range 42-82) suffering from CD were imaged. Four of these patients showed no elevated intestinal 18F-FDG uptake while five had minor diffuse intestinal 18F-FDG accumulation with SUVs ranging between 2.2 and 4.6 (mean 3.4 (SD 0.89)). In the remaining three patients with diffuse intestinal 18F-FDG uptake, no SUV could be calculated. SUVs in patients with ETCL were remarkably higher than in patients suffering from CD (p=0.011), irrespective of the activity of CD at the time of imaging. CONCLUSION: In spite of the relatively small number of patients, our results clearly indicate the potential value of 18F-FDG-PET for diagnosing and imaging ETCL. In addition, the data also suggest that 18F-FDG-PET may lead to early diagnosis in individuals developing ETCL in the context of longstanding CD. This is due to the fact that 18F-FDG does not appear to significantly accumulate in the gut of patients with CD, irrespective of disease activity.

Adult↗

PubMed2003

Prognostic value of FDG-PET in malignant lymphoma.

Lymphomas have represented an indication for nuclear medicine investigations for 30 years. Gallium-67 scintigraphy has been shown to be a valuable complementary method in Hodgkin's disease and non-Hodgkin lymphoma for detecting viable residual lesions after chemotherapy and for diagnosis of a relapse. Thallium-201 is of interest in differentiating cerebral lymphomas from infectious lesions in AIDS patients but less useful in extra-cerebral lymphomas. PET with fluorine-18-FDG is more accurate than 67Ga in lymphoma. In patients with a positive PET scan after chemotherapy an early relapse occurs in up to 100%, while more than 80% of patients with a negative PET will have a long-term remission. Most studies show that FDG-PET is significantly correlated with patient outcome whereas there is much weaker or even no correlation for CT. The main reason is that PET is not bound to morphological criteria like lymph node size while CT is often not able to differentiate between residual tumour and post-therapeutic fibrosis. Therefore, based on a considerable number of clinical studies, FDG-PET gains increasing significance for staging, restaging and therapy monitoring in malignant lymphomas.

Citrates↗

PubMed2002

Positron emission tomography with [18F]2-fluoro-D-2-deoxyglucose (FDG-PET) predicts relapse of malignant lymphoma after high-dose therapy with stem cell transplantation.

We have determined the predictive value of [18F]2-fluoro-2-deoxy-glucose (FDG-PET) in patients with Hodgkin's disease (HD) and aggressive non-Hodgkin's lymphoma (NHL) scheduled for high-dose therapy with stem cell transplantation (HDT/SCT). Inclusion criteria were the presence of an FDG-PET scan after chemotherapy (ChT) within 8 weeks prior to HDT/SCT and available follow-up data. Sixteen patients (10 NHL and six HD) were observed during a follow-up period of 4 to 28 months (median 13 months). Before SCT, five patients had a negative PET, three were weakly positive, two moderately positive, and six strongly positive. None of the five patients with a negative PET before HDT/SCT relapsed and two of three patients with a weakly positive scan are still in remission after HDT/SCT. Of eight patients with a moderate or high positive PET before HDT/SCT, seven relapsed and one died of early HDT/SCT related complications (P< 0.01). Three of eight relapsing patients died of lymphoma 5 to 10 months after SCT and in one additional patient not responding to HDT/SCT, the main cause of death was chronic toxicity 4 months after transplantation. After 12 months, in PET-negative patients the overall and relapse-free survival was 100%, in PET-positive patients 55% and 18%, respectively. In NHL, two patients with negative PET, but with an age-adjusted international prognostic index (AaIPI) of 2 and one with AaIPI = 1 are still in remission. In the seven PET-positive subjects, one patient with AaIPI = 0, three with AaIPI = 1, and two with AaIPI = 2 relapsed. We conclude that FDG-PET is accurate in the prediction of relapse prior to HDT/SCT in patients with lymphoma. It provides additional information when compared with the AaIPI.

Adult↗

PubMed2002

Pharmacokinetic and mass balance study of unlabelled and (14)C-labelled emedastine difumarate in healthy volunteers.

1. In a mass balance study, six healthy male volunteers received a single oral dose of 4 mg (14)C-labelled emedastine difumarate. The pharmacokinetics of the total radioactivity and unchanged drug were assessed over 48 h. Urinary and faecal excretion were measured over 120 h. Additionally, urinary metabolites were investigated. 2. In a single- and multiple-dose pharmacokinetic study, nine male and nine female healthy volunteers received 2 mg oral emedastine difumarate b.i.d. or 4 mg o.d. for 7 consecutive days. The plasma pharmacokinetics were assessed on day 1 and at steady-state. 3. The mass balance study demonstrated almost complete gastrointestinal absorption of the administered dose. A total of 94.2% of the radioactivity was eliminated via the kidneys. Unchanged emedastine in the urine accounted for <5% of dose. 5-Hydroxy, 6-hydroxy and N-oxide metabolites previously identified in the Japanese were present in Caucasian subjects. 4. AUC after single and multiple dosing were dose-proportional. On day 7, no statistical difference in AUC(0-24) could be detected between the two regimens, with AUC = 70.6 +/- 36.1 and 71.7 +/- 52.3 ng h ml(-1), respectively. There were no gender differences in the pharmacokinetics of emedastine. 5. The results corroborate the use of emedastine in a Caucasian population and support the extrapolation of safety and efficacy data from Asians to Caucasians.

Adult↗

PubMed2001

Predictive impact of 2-18fluoro-2-deoxy-D-glucose positron emission tomography for residual postchemotherapy masses in patients with bulky seminoma.

PURPOSE: To establish the predictive potential of 2-18fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) for detecting viable tumor tissue in residual postchemotherapy masses of seminoma patients. PATIENTS AND METHODS: In this prospective multicenter trial, results of FDG PET studies in seminoma patients with postchemotherapy masses > or = 1 cm were correlated with either the histology of the resected lesion or the clinical outcome on follow-up without resection. Negative PET scans of residual lesions that were devoid of viable tumor tissue on resection or disappeared, shrunk, or remained stable in size for at least 2 years were rated as true-negative (TN). Positive scans without histologic or clinical evidence of tumor tissue were classified as false-positive. In patients with histologically positive or progressive lesions, positive PET scans were defined as true-positive (TP) and negative scans, false-negative (FN). RESULTS: Thirty-seven PET scans of 33 patients were assessable at a median follow-up time of 23 months (range, 2 to 46 months). Histologic data were available from nine patients who had undergone resection. Twenty-eight patients were followed-up clinically and radiologically. Twenty-eight scans were TN, eight were TP, and one was FN. All 14 residual lesions more than 3 cm and 22 (96%) of the 23 < or = 3 cm were correctly predicted by FDG PET. The specificity (100%; 95% confidence interval [CI], 87.7% to 100%), sensitivity (89%; 95% CI, 51.7% to 99.7%), positive predictive value (100%), and the negative predictive value (97%) of FDG PET were superior to data obtained by assessing residual tumor size (< or = or > 3 cm). CONCLUSION: FDG PET is a clinically useful predictor of viable tumor in postchemotherapy residuals of pure seminoma, especially those greater than 3 cm.

Adult↗

PubMed2001

[Analysis of the convergence relation of reconstructed algorithms disregarding local and global visual evaluations].

Tomographic reconstruction methods used in positron emission tomography are classified in two major groups: the traditionally and still widely applied filtered backprojection, and the iterative methods based on statistical models. This study focused on the objective comparison of different reconstruction algorithms, excluding criteria based on pure visual evaluation. The evaluation criteria were mathematically defined parameters, i.e., mean square error, standard deviation, signal-to-noise ratio and contrast recovery. The methods used for comparison were the classical filtered backprojection, the maximum likelihood expectation maximization algorithm, the maximum a-posteriori reconstruction model based on the Bayes Theorem, as well as the acceleration algorithms based on ordered subsets and high over-relaxation. These algorithms were evaluated by means of a mathematical brain phantom and of a physical spherical phantom. In terms of the applied parameters, the majority of the experiments showed a quantifiable superiority of the iterative methods compared the filtered backprojection.

Algorithms↗

PubMed2001

FDG-PET in adrenocortical carcinoma.

Adrenal cortical carcinoma (ACC) is a rare malignant neoplasm with a poor prognosis. Radical surgery of the primary tumor and of local as well as of distant recurrence is the only effective treatment, and requires accurate and early localization of recurrent tumors. In this regard, we prospectively scanned 10 patients with ACC, 8 during follow-up and 2 at primary work-up. In all patients PET scans from the neck to the upper thighs were obtained 45 minutes after injection of 370 MBq [18F]FDG. Reading was done visually, with the investigator blinded to the results of other diagnostic modalities. All known sites of ACC lesions showed markedly increased FDG uptake. In 3 patients, previously unknown lesions were identified by PET in the lung (one lesion), the abdomen (3 lesions), and the skeleton (multiple), respectively. One false positive liver focus was shown by PET aside from the true positive lung metastases in the same patient. The sensitivity/specificity of PET based on different organs was 100/97%, that based on the number of PET-detected lesions (N = 23) was 100/95%. PET altered or influenced the tumor stage in 3/10 patients, modifying the subsequent therapeutic management in 2/10 patients. We conclude that FDG-PET is highly useful in ACC and should be included in the work-up for initial staging as well as for follow-up.

Abdominal Neoplasms↗