Altered cerebral glucose metabolism normalized in a patient with a pediatric autoimmune neuropsychiatric disorder after streptococcal infection (PANDAS)-like condition following treatment with plasmapheresis: a case report.

BACKGROUND: Pediatric autoimmune neuropsychiatric disorder after streptococcal infection (PANDAS) is a specific autoimmune response to group-A streptococcal infections in children and adolescents with a sudden onset of obsessive-compulsive disorders or tic-like symptoms. Cerebral metabolic changes of patients have not yet been observed. CASE PRESENTATION: We present a case of an 18-year old male with a PANDAS-like condition after developing tic-like symptoms and involuntary movements three weeks after cardiac surgery. The patient had suffered from pharyngotonsillitis before the symptoms started. The anti-streptolysin O (ASO) titer was elevated (805 kU/l). Antibiotic therapy did not improve his condition. Intravenous immunoglobulins and high-dose cortisone therapy had minor beneficial effects on his involuntary movements. 18F-Fluorodeoxyglucose positron emission tomography/ computer tomography (18F-FDG PET/CT) demonstrated pronounced hypermetabolism of the basal ganglia and cortical hypometabolism. The patient was treated with five cycles of plasmapheresis. A marked clinical improvement was observed after four months. Cerebral metabolic alterations had completely normalized. CONCLUSIONS: This is the first report of cerebral metabolic changes observed on FDG-PET/CT in a patient with a PANDAS-like condition with a normalization following immunomodulatory treatment. Cerebral FDG-PET/CT might be a promising tool in the diagnosis of PANDAS.

Combined measurement of tumor perfusion and glucose metabolism for improved tumor characterization in advanced cervical carcinoma. A PET/CT pilot study using [15O]water and [18F]fluorodeoxyglucose.

BACKGROUND AND PURPOSE: The aim of this pilot study was (1) to evaluate the combination of [(18)F]fluorodeoxyglucose (FDG) and [(15)O]water for detection of flow-metabolism mismatch in advanced cervical carcinomas, i.e., increased glycolysis at low blood flow, as a possible parameter for prediction of response to treatment, and (2) to propose a method for automated quantification of its spatial extent. PATIENTS AND METHODS: The study retrospectively included 10 women with advanced cervical carcinoma in whom PET with both FDG and [(15)O]water had been performed prior to therapy. The metabolically active tumor volume was delineated automatically in the FDG images. For computation of the regional blood flow in the tumor, a recovery corrected image-derived arterial input function was used. A tumor voxel was classified as mismatched when the voxel SUV of FDG was larger than the median tumor SUV and the voxel perfusion (K1) was smaller than the median perfusion. The absolute mismatch volume (aMMV) was defined as the volume of all mismatched voxels in ml, and the relative mismatch volume (rMMV) as the ratio of the aMMV to the metabolic tumor volume in percent. RESULTS: The tumors were quite heterogeneous with respect to both FDG uptake and perfusion. The aMMV clustered into 2 groups: "large aMMV" ≥ 10 ml in 40 % of patients and "small aMMV" ≤ 5 ml in 60 % of patients. The rMMV ranged from 12.7-24.9 %. There was no correlation between rMMV and metabolic tumor volume. There was a tendency (p = 0.126) for an association between rMMV and histological grading, rMMV being about 20 % higher in G3 than in G2 tumors. rMMV did not correlate with SUV or perfusion. CONCLUSION: These results suggest that combined PET with FDG and [(15)O]water allows detection and quantitative characterization of flow-metabolism mismatch in advanced cervical carcinomas.

MR Imaging of Prostate Cancer: Diffusion Weighted Imaging and (3D) Hydrogen 1 (H) MR Spectroscopy in Comparison with Histology.

UNLABELLED: Purpose. To evaluate retrospectively the impact of diffusion weighted imaging (DWI) and (3D) hydrogen 1 ((1)H) MR-spectroscopy (MRS) on the detection of prostatic cancer in comparison to histological examinations. MATERIALS AND METHODS: 50 patients with suspicion of prostate cancer underwent a MRI examination at a 1.5T scanner. The prostate was divided into sextants. Regions of interest were placed in each sextant to evaluate the apparent diffusion coefficient (ADC)-values. The results of the DWI as well as MRS were compared retrospectively with the findings of the histological examination. Sensitivity and specificity of ADC and metabolic ratio (MET)-both separately and in combination-for identification of tumor tissue was computed for variable discrimination thresholds to evaluate its receiver operator characteristic (ROC). An association between ADC, MET and Gleason score was tested by the non-parametric Spearman ρ-test. Results. The average ADC-value was 1.65 ± 0.32mm(2)/s × 10(-3) in normal tissue and 0.96±0.24 mm(2)/s × 10(-3) in tumor tissue (mean ± 1 SD). MET was 0.418 ± 0.431 in normal tissue and 2.010 ± 1.649 in tumor tissue. The area under the ROC curve was 0.966 (95%-confidence interval 0.941-0.991) and 0.943 (0.918-0.968) for DWI and MRS, respectively. There was a highly significant negative correlation between ADC-value and the Gleason score in the tumor-positive tissue probes (n = 62, ρ = -0.405, P = .001). MRS did not show a significant correlation with the Gleason score (ρ = 0.117, P = .366). By using both the DWI and MRS, the regression model provided sensitivity and specificity for detection of tumor of 91.9% and 98.3%, respectively. Conclusion. The results of our study showed that both DWI and MRS should be considered as an additional and complementary tool to the T2-weighted MRI for detecting prostate cancer.

FDG PET/CT in cancer therapy monitoring: computer-assisted analysis of baseline together with up to two follow-ups.

OBJECTIVES: We developed and tested a software tool for computer-assisted analysis of FDG-PET/CT in cancer therapy monitoring. The tool provides automatic semi-quantitative analysis of a baseline scan together with up to two follow-up scans (standardized uptake values, glycolytic volume). The tool also supports visual analysis by local spatial registration which allows display of tumor lesions with the same orientation in all scans. The tool's stability and accuracy was tested at typical everyday image quality. PATIENTS, METHODS: Ten unselected cancer patients in whom three FDG PET/CT scans had been performed were included. A total of 18 lesions were analyzed. RESULTS: Automatic lesion tracking worked properly in all lesions but one. In this lesion local coregistration had to be adjusted manually which, however, is easily performed with the tool. Semi-automatic lesion segmentation and fully automatic semi-quantitative analysis worked properly in all cases. Computer-assisted analysis was significantly less time consuming than manual analysis. CONCLUSIONS: The novel software tool appears useful for analysis of FDG-PET/CT in cancer therapy monitoring in clinical routine patient care.

Screening for atherosclerotic plaques in the abdominal aorta in high-risk patients with multicontrast-weighted MRI: a prospective study at 3.0 and 1.5 tesla.

OBJECTIVE: This prospective study compares MRI of atherosclerotic plaque in the abdominal aorta at 3 T with that at 1.5 T in patients suffering from hereditary hyperlipidaemia, a major risk factor for atherosclerosis. METHODS: MRI of the abdominal aorta at 1.5 and 3 T was performed in 21 patients (mean age 58 years). The study protocol consisted of proton density (PD), T(1), T(2) and fat-saturated T(2) weighted black blood images of the abdominal aorta in corresponding orientation. Two independent radiologists performed image rating. First, image quality was rated on a five-point scale. Second, atherosclerotic plaques were scored according to the modified American Heart Association (AHA) classification and analysed for field strength-related differences. Weighted κ statistics were calculated to assess interobserver agreement. RESULTS: Interobserver agreement was substantial for nearly all categories. MRI at 3 T offered superior image quality in all contrast weightings, most significantly in T(1) and T(2) weighted techniques. Plaque burden in the study collective was unexpectedly moderate. The majority of plaques were classified as AHA III lesions; no lesions were classified above AHA V. There was no significant influence of the field strength regarding the AHA classification. CONCLUSION: Abdominal aortal plaque screening is basically feasible at both field strengths, whereas the image quality is rated superior at 3 T. However, the role of the method in clinical practice remains uncertain, since substantial findings in the high-risk collective were scarce.

Dementia and leukoencephalopathy due to lymphomatosis cerebri.

Lymphomatosis cerebri (LC) is a rare variant of primary central nervous system lymphoma (PCNSL). Clinically, the disease typically presents with a rapidly progressive dementia and unsteadiness of gait. Its presentation on cerebral MRI, which is characterised by diffuse leukoencephalopathy without contrast enhancement, often causes diagnostic confusion1 with suspected diagnoses ranging from Binswanger's disease to leukoencephalopathy or encephalomyelitis. Here we report a patient with subacute dementia and diffuse bilateral white matter changes in the cerebral hemispheres and additional involvement of the brainstem, basal ganglia and thalamus on MRI. Initially, she was considered to suffer from an autoimmune encephalitis, transiently responded to immunosuppression but then developed multiple solid appearing cerebral lymphomas.

Time benefit in the assessment of recurrences following fractionated radiotherapy in an experimental tumour system using positron-emission tomography with 18F-fluorodeoxyglucose.

PURPOSE: To determine the sensitivity and specificity of 18F-fluorodeoxyglucose-positron-emission tomography (FDG-PET) in the diagnosis of R1H tumours after fractionated radiotherapy, and the dependency of sensitivity and specificity on time after therapy. In addition, the time benefit of FDG-PET concerning early recognition of recurrences after fractionated radiotherapy was assessed. MATERIAL AND METHODS: Subcutaneously growing rat rhabdomyosarcoma R1H tumours were irradiated by applying total doses of 80 or 85 Gy after reaching a start volume of 0.8 cm3. Twenty animals were treated. Tumour volume was determined twice a week. FDG-PET was performed weekly before, during and for 6 months after therapy using a conventional full-ring whole-body PET scanner. In total, 600 PET results were evaluated qualitatively using a six-scale score. PET results and actual tumour volumes were compared. The sensitivity and specificity of tumour detection by PET was calculated for different times after the onset of therapy. The optimal score for tumour detection and the influence of time after therapy on the quality of PET (time benefit) was evaluated using receiver-operating characteristics. RESULTS: After irradiation, 8/20 tumours (40%) were locally controlled, while 12/20 recurred. In this tumour model, evidence of relapse is assured when a volume of 0.1 cm3 is reached. Sensitivity of tumour diagnosis by PET increases with time, i.e. with the volume of recurrent tumours after the onset of therapy, mounting to > 0.95 after 100 days. Specificities of 0.95-1.0 were determined after therapy, showing no increase with time. Tumour diagnosis by PET is highly accurate when performed 80 days after the start of treatment. On average, tumours were recognized by PET on 31, 62, 74 and 81 days (median) before approaching volumes of 0.2, 0.5, 0.8 or 1.0 cm3, respectively. CONCLUSION: An experimental system was implemented that allows reproducible detection of recurrent R1H tumours after radiotherapy using FDG-PET. The usefulness of PET as a diagnostic test for R1H tumours is very good and a reliable resolution for PET is demonstrated for volumes < 1 cm3. The results indicate that FDG-PET enables early recognition of recurrences after fractionated radiotherapy.

FDG PET in the diagnosis of hilar cholangiocarcinoma.

Resectional surgery offers a curative intent and a survival benefit for patients with hilar cholangiocarcinoma, but is associated with high morbidity. Since morphological imaging cannot solve differential diagnosis preoperatively, in order to exclude patients inappropriate to this aggressive surgery, we evaluated the impact of functional imaging using fluorodeoxyglucose positron emission tomography (FDG PET) in the detection of cholangiocarcinoma and its usefulness in the differentiation from benign Klatskin tumour-mimicking lesions. Fifteen consecutive patients aged 47-78 years underwent standardized whole-body FDG PET with attenuation correction before potentially curative surgery using a conventional full-ring PET scanner with an axial field-of-view of 16.2 cm. FDG PET was evaluated visually and semiquantitatively using tumour-to-background ratios (T/B) ratios. All lesions were evaluated histopathologically. FDG PET presumed to be indicative for carcinoma was positive in 12 of 15 patients, true positive in 10 (T/B ratio, 3.2+/-1.9) and false positive in two of them (T/B ratios, 2.1 and 2.8) with Klatskin tumour-mimicking lesions. While all true positive PET results were seen in the tubular type of cholangiocarcinoma with a high amount of tumour cells and only low production of mucus, a false negative FDG PET in three patients was observed in mucinous adenocarcinoma. Additionally, FDG PET detected locoregional lymph nodes in two patients and distant metastases in a further three patients. Due to false positive results FDG PET does not allow the differentiation of benign from malignant lesions, and FDG PET should be avoided in patients with mucinous cholangiocarcinoma. However, FDG PET may have significant influence on the treatment strategy in as much as 20% of the patients, since it may detect distant metastases.

Long-term effects of 'ecstasy' abuse on the human brain studied by FDG PET.

The popular recreational drug, 'ecstasy', mainly contains 3,4-methylenedioxymethamphetamine (MDMA) as the psychotropic agent. MDMA is suspected of causing neurotoxic lesions to the serotonergic system as demonstrated by animal studies, examinations of human cerebrospinal fluid, and the first positron emission tomography (PET) studies using the serotonin transporter ligand [11C]-McN5652. Damage of serotonergic afferents might mediate long-lasting alterations of cerebral glucose metabolism as a secondary effect. To study a relationship between ecstasy use and long-lasting alterations, PET using 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) was performed in 93 ecstasy users and 27 subjects without any known history of illicit-drug abuse. As an index of glucose metabolism, mean normalized FDG uptake was determined in both groups using a computerized brain atlas, and was compared for a selected number of brain regions. FDG uptake was normalized in each individual by dividing local FDG uptake by the maximum FDG uptake in the individual's brain. Within the group of ecstasy users we examined the relationship between FDG uptake and cumulative ecstasy dose, time since last ecstasy ingestion at the time of PET scanning, and age at first ecstasy use, respectively. Normalized FDG uptake was reduced within the striatum and amygdala of ecstasy users when compared to controls. No statistically significant correlation of the FDG uptake and the cumulative dose of ecstasy was detected. A positive correlation was found in the cingulate between FDG uptake and the time since last ecstasy ingestion. As compared to the control group, normalized FDG uptake in the cingulate was reduced in ecstasy users who took ecstasy during the last 6 months, while it was elevated in former ecstasy users who did not consume ecstasy for more than 1 year. FDG uptake was significantly more affected in ecstasy users who started to consume ecstasy before the age of 18 years. In conclusion, ecstasy abuse causes long-lasting effects on glucose metabolism in the human brain. These effects are more severe in the case of very early abuse. However, several questions still remain to be answered, i.e. the correlation of the neuronal alterations and the history of ecstasy use (cumulative dose, and time since the last dose) and its reversibility.

In vitro and in vivo tracer characteristics of an established multidrug-resistant human colon cancer cell line.

UNLABELLED: 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) has been suggested as a tracer for the scintigraphic detection of multidrug resistance (MDR). The aim of this study was to compare MDR characteristics in vitro and in vivo by immunohistochemic and functional uptake assays in established tumor cell lines cultured and grown in severe combined immunodeficient (SCID) mice. METHODS: The presence of MDR was assessed in vitro in drug-resistant HT-29(mdr1) colon carcinoma cells and in nonresistant HT-29(par) cells by JSB-1 immunohistochemistry, uptake of the fluorescent dye Rhodamine 123, and quantitative measurement of 99mTc-MIBI accumulation. For in vivo imaging, SCID mice bearing subcutaneous xenografts of these cell lines were injected with 99mTc-MIBI and 18F-FDG for scintigraphic and PET examination. After imaging, tumors were analyzed by immunohistochemistry and electron microscopy. RESULTS: All HT-29(mdr1) cells cultured in vitro exhibited distinct JSB-1 immunoreactivity, although to a variable degree, whereas HT-29(par) cells were completely devoid of JSB-1 staining. Rhodamine 123 accumulated poorly in HT-29(mdr1) cells but strongly in HT-29(par) cells. Accumulation of 99mTc-MIBI was 0.05% +/- 0.01% of the activity of the external medium in HT-29(mdr1) cells, but about eight times higher in HT-29(par) cells (0.40% +/- 0.09%), a very low percentage compared with other tumor cell lines. No difference in 201TlCl accumulation was observed between both cell lines. In vivo, neither HT-29(par) nor HT-29(mdr1) tumors grown in SCID mice could be detected by 99mTc-MIBI scintigraphy. In FDG PET, both HT-29(mdr1) and HT-29(par) tumors were clearly visible. FDG uptake was, however, markedly higher in HT-29(par) than in HT-29(mdr1) tumors. Both tumor types were poorly vascularized, as shown histologically. JSB-1 immunoreactivity was absent in all HT-29(par) tumors examined, whereas the majority of HT-29(par) tumor cells were stained. Electron microscopy showed that HT-29(par) tumors contained significantly less mitochondria than hepatocytes of the SCID mouse liver, which displayed high 99mTc-MIBI uptake in our scintigraphy studies. CONCLUSION: Sufficient 99mTc-MIBI uptake is the major prerequisite for distinguishing successfully between drug-resistant and sensitive cells. Negative 99mTc-MIBI scintigrams are not necessarily associated with MDR expression. In some tumors, FDG may be an in vivo marker for MDR as suggested by PET.

18FDG-PET following treatment as valid predictor for disease-free survival in Hodgkin's lymphoma.

PURPOSE: The value of 18FDG-PET to predict the outcome after therapy in Hodgkin's lymphoma was compared to morphologic staging and ESR. PATIENTS AND METHODS: A total of 50 concurrent 18FDG-PET and CT studies were performed in 37 patients with Hodgkin's lymphoma. ESR was evaluated 32 times after treatment was completed. RESULTS: Out of 39 residual masses found by CT 8 relapses could be proven. Out of 11 CT exams with CR 3 relapses occurred. CT turned out to show a sensitivity, specificity, PPV, NPV, and accuracy of 72%, 21%, 21%, 73%, and 32%, with respect to predict disease-free survival (DFS). 18FDG-PET was positive in 22 examinations with 10 recurrences in this group. Out of 28 negative 18FDG-PET 1 relapse developed 3 years later. 18FDG-PET turned out to show promising sensitivity, specificity, PPV, NPV, and accuracy of 91%, 69%, 46%, 96%, 74%, with respect to predict DFS. ESR was elevated in 12 studies of which 5 relapses could be proven, while out of 20 normal ESR-studies 3 relapses occurred. Thus, ESR turned out to show sensitivity, specificity, PPV, NPV, and accuracy of 63%, 71%, 42%, 85%, and 75%, with respect to predict DFS. In summary, only 18FDG-PET was able to predict DFS statistically significant. CONCLUSION: 18FDG-PET can be very useful in patients with residual masses after treatment.

Impact of FDG PET on patients with differentiated thyroid cancer who present with elevated thyroglobulin and negative 131I scan.

UNLABELLED: FDG PET is increasingly performed in patients with differentiated thyroid cancer who present with elevated human thyroglobulin (hTG) levels and negative 131I scan. The aim of this study was to evaluate the impact of FDG PET on treatment in these patients. METHODS: A total of 118 FDG PET studies were performed on 64 patients, and follow-up data were available for all patients. Whole-body images were acquired 1 h after intravenous injection of 370 MBq (10 mCi) FDG using a PET scanner with an axial field of view of 16.2 cm. Tumor-suspicious FDG PET studies were evaluated by histology, cytology, 131I uptake, CT or MRI, and follow-up of hTg levels. The therapeutic consequence was noted for each patient. Moreover, results of FDG PET were correlated with hTg levels. RESULTS: Forty-four patients had positive scans, which were proven to be true-positive in 34 patients, whereas 7 patients had false-positive findings. Two patients exhibited a secondary malignancy. One patient did not fit in any category, having true-positive, false-positive, and false-negative findings. On the other hand, 20 patients had negative scans. These were true-negative findings in 5 patients, whereas the remaining 15 patients had false-negative results. Accordingly, the positive predictive value of FDG PET was 83% (34/41), whereas the negative predictive value was 25% (5/20). Treatment was directly changed in 19 of 34 patients with true-positive PET studies: 18 patients had further surgery, and 4 patients were referred for external irradiation, 3 of them after incomplete removal of local recurrences. FDG PET showed widespread disease in 7 patients; thus, palliative treatment, rather than curative therapy, was initiated. True-positive FDG PET findings were correlated positively with increasing hTg levels (i.e., FDG PET was true-positive in 11%, 50%, and 93% of patients with hTg levels of <10, 10-20, and >100 microg/L, respectively). CONCLUSION: FDG PET is a valuable diagnostic tool in patients with differentiated thyroid cancer who present with increased hTg levels and negative 131I scans because it permits selection of patients for surgery, which may be curative. FDG PET is most promising at hTg levels of >10 microg/L.

FDG PET detection of unknown primary tumors.

UNLABELLED: The management of patients presenting with metastases of unknown primary origin remains a clinical challenge despite a large variety of imaging modalities. The aim of this study was to evaluate FDG PET in detecting the sites of primary cancer in these patients. METHODS: Fifty-three patients with metastatic cervical adenopathy (n = 44) or extracervical metastases (n = 9) of unknown primary origin were included after extensive but inconclusive conventional diagnostic work-up. Patients received 370 MBq FDG (10 mCi) intravenously, and whole-body images were acquired at 60 min after injection. Clinical, surgical, and histopathologic findings and complete correlative imaging were used to assess the results. RESULTS: In 27 of 53 patients FDG PET showed focal tracer accumulations corresponding to potential primary tumor sites located in the lungs (n = 12), the palatine tonsil (n = 5), the salivary glands (n = 2), the nasopharynx (n = 1), the oropharynx (n = 3), the maxillary sinus (n = 1), and the larynx (n = 1). Moreover, in 2 patients FDG PET revealed lesions suspected to be tumors in the breast and the ileocolonic area. In 20 (37.8%) of these 53 patients FDG PET was true-positive, identifying the primary tumor in the lungs (n = 10), the head and neck region (n = 8), the breast (n = 1), and the ileocolonic area (n = 1). In 6 of 27 patients FDG PET was false-positive, predominantly identifying suspicious areas in the palatine tonsil (n = 3). One patient denied further diagnostic work-up after PET; thus, positive PET could not be evaluated. In 26 of 53 patients PET did not reveal lesions suspected to be the primary. However, primary tumors were not found in these patients at clinical follow-up. CONCLUSION: FDG PET is a valuable diagnostic tool in patients with cancer of unknown primary because it imaged unknown primary tumors in about one third of all patients investigated. In addition, FDG PET assists in both guiding biopsies for histologic evaluation and selecting the appropriate treatment protocols for these patients.

Performance evaluation of PET scanners: testing of geometric arc correction by off-centre uniformity measurement.

The aim of this study was to demonstrate the necessity of an off-centre uniformity measurement during performance evaluation and acceptance testing of a positron emission tomography (PET) system. To this end, the effect of different methods of geometric arc correction on image uniformity was considered. The arc correction routine of the system software of a particular PET scanner family was tested in computer simulations, phantom measurements and a patient study. Various methods of geometric arc correction--nearest neighbour interpolation, linear interpolation and cubic smoothing spline interpolation--were applied to the same data. Uniformity was evaluated both visually and quantitatively using intensity profiles and regions of interest. The arc correction routine of the PET scanner family produced significant ring artefacts and led to overestimation of tracer uptake by up to 15%. Since uniformity measurements are usually performed using a cylindrical phantom at the centre of the transverse field of view, these artefacts are not detected. In conclusion, the standards for performance evaluation of a PET scanner should be extended by inclusion of an off-centre uniformity measurement at the edge of the transverse field of view. On the basis of our comparison of different methods for geometric arc correction, we suppose that cubic smoothing spline interpolation might improve the relation between statistical noise reduction and spatial resolution as compared with conventional linear interpolation.

Radioprotection of salivary glands by amifostine in high-dose radioiodine treatment. Results of a double-blinded, placebo-controlled study in patients with differentiated thyroid cancer.

BACKGROUND AND PURPOSE: Parenchymal impairment of salivary glands following high-dose radioiodine treatment is a well-known side effect in general caused by free radicals. Therefore, the radioprotective effect of the radical scavenger amifostine was evaluated prospectively in patients receiving high-dose radioiodine treatment. PATIENTS AND METHODS: Parenchymal function was assessed by quantitative salivary gland scintigraphy performed in 50 patients with differentiated thyroid cancer prior to and 3 months after high-dose radioiodine treatment with either 3 GBq 131I (n = 21) or 6 GBq 131I (n = 29) in a double-blinded, placebo-controlled study. Twenty-five patients treated with 500 mg/m2 amifostine intravenously prior to high-dose radioiodine treatment were compared to 25 control patients receiving physiological saline solution. Xerostomia was graded according to WHO-criteria. RESULTS: In 25 control patients high-dose radioiodine treatment significantly (p < 0.001) reduced parenchymal function of parotid and submandibular glands by 40.2 +/- 14.1% and 39.9 +/- 15.3%, respectively. Nine out of these 25 patients developed Grade I and 2 Grade II xerostomia. In contrast, in 25 amifostine-treated patients there was no significant (p = 0.691) decrease in parenchymal function following high-dose radioiodine treatment, and xerostomia did not occur in any of them. CONCLUSION: Parenchymal damage of salivary glands induced by high-dose radioiodine treatment can be significantly reduced by amifostine which may improve quality of life of patients with differentiated thyroid cancer.

[Onco-PET: lesion detection by monitor versus standardized film documentation]. / Onko-PET: Bildanalyse mittels Monitor versus standardisierter Filmdokumentation.

AIM: Lesion detection and localization of 2-[18F]fluoro-2-deoxy-D-glucose (F-18-FDG) Onco-PET-Investigations are usually performed on-line at the computer display. The aim of the present study was to evaluate the clinical efficacy of a standardized film documentation as an alternative approach. METHODS: 100 Onco-PET-investigations without attenuation correction were analyzed with regard to number and localization of lesions suspicious of malignancy. A standardized documentation on film was developed including 1. transversal slices of the brain, 2. coronal slices and maximum-intensity-projections (MIPs) of the head/neck region and 3. of the trunk and 4. MIPs of the legs. These transparencies were analyzed at the light box. An additional analysis on the computer display was performed slice by slice in coronal, transversal and sagittal directions for the whole body. RESULTS: A total of 315 lesions were detected in 100 patients. In 96/100 patients the two modalities agreed both in number and localization of tumor-suspicious lesions. 7 lesions in the legs of 3 patients didn't show when interpreting the films (MIPs only). In 2/100 patients additional analysis on the computer display caused a change in the localization of 9/315 lesions. 8 of these were located in the legs. When adding coronal slices for the documentation of the lower extremities all the lesions were shown. Moreover, all lesions were localized correctly except one clinically non-relevant change of localization out of a total of 322 lesions. CONCLUSION: The newly developed standardized documentation supports the concept of film reading and reporting of onco-PET investigations, restricting an additional on-line analysis to rare cases only. Furthermore, the intention of the "Arbeitsgemeinschaft Standardisierung" (work group standardisation) are met, i.e. to ease analysis of follow-up studies acquired at different places.

[Granulation tissue: pitfall in therapy control with F-18-FDG PET after chemotherapy]. / Granulationsgewebe: Pitfall in der Therapiekontrolle mit F-18-FDG-PET nach Chemotherapie.

False positive findings in primary tumor and metastasis diagnostics by FDG-PET due to FDG-uptake in inflammatory foci are documented in literature. The demonstrated case reveals that increased uptake of FDG in activated neutrophile granulocytes and macrophages has to be taken into consideration in therapy control under chemotherapy, too. In a 53 year old patient FDG-PET was performed after chemotherapy of an abdominal Non-Hodgkin lymphoma for evaluation of persistent tumor vitality. The margin of the persisting mass showed increased uptake of glucose. Histology documented a necrotic center surrounded by granulation tissue.

Effect of attenuation correction on lesion detectability in FDG PET of breast cancer.

UNLABELLED: The aim of this study was to compare the visual analysis of attenuation-corrected and noncorrected 18F-fluoro-2-deoxy-D-glucose (FDG) PET images in patients with primary or metastatic breast cancer using standardized film documentation and to evaluate the influence of attenuation correction on lesion detectability. METHODS: Standard FDG PET of the breasts and of the axillary regions was performed on 28 women with breast cancer. Transmission scans were acquired for attenuation correction after administration of FDG. Transverse and coronal slices and maximum intensity projections both with and without attenuation correction were documented in a standardized manner on film. Noncorrected images were displayed with an upper threshold of five times the mean activity in normal lung tissue. Attenuation-corrected images were documented with an upper threshold of a standardized uptake value of five. Two independent nuclear medicine physicians, who were unaware of the results of clinical investigation, other imaging modalities and histopathologic findings, interpreted the images visually, noncorrected images first. RESULTS: One hundred eighty-four of 189 lesions in 28 of 28 patients were found on attenuation-corrected and noncorrected images. Seventeen lesions were found in the breasts of 12 patients. In 18 patients, 31 axillary lesions were found. Moreover, 141 lesions representing distant metastases were detected in 18 patients. Attenuation-corrected images showed the same lesions in all patients but 2, in whom 5 of 189 small pulmonary lesions (2.6%) were not detected. Iterative reconstruction did not improve detectability of these lesions on attenuation-corrected images. These lesions were confirmed by CT, which revealed diameters of <1 cm. CONCLUSION: Attenuation correction by transmission measurement after injection may impair lesion detectability in PET for staging of breast cancer patients. When using the image modalities described, noncorrected PET images should be considered in image analysis.

Salivary gland protection by S-2-(3-aminopropylamino)-ethylphosphorothioic acid (amifostine) in high-dose radioiodine treatment: results obtained in a rabbit animal model and in a double-blind multi-arm trial.

Since differentiated thyroid cancer has an excellent prognosis, reduction of long-term side effects of high-dose radioiodine treatment (HD-RIT), i.e. salivary gland impairment is important. Thus, radioprotective effects of amifostine were studied. Salivary gland function was quantified by scintigraphy both in rabbits and patients. Fifteen rabbits were studied prior to and up to 6 months after HD-RIT applying 2 GBq 131I. Ten animals received 200 mg/kg amifostine prior to HD-RIT, and five served as controls. Animals were examined histopathologically. Fifty patients with differentiated thyroid cancer were evaluated prospectively prior to and 3 months after HD-RIT with either 3 or 6 GBq 131I in a double-blind, placebo-controlled study. Twenty-five patients were treated with 500 mg/m2 amifostine intravenously prior to HD-RIT, and 25 patients receiving physiological saline solution served as controls. Complete ablation of the thyroid was achieved in all rabbits four weeks after HD-RIT. In control rabbits 6 months after HD-RIT parenchymal function was reduced significantly (p < 0.0001) by 75.3 +/- 5.3% and 53.6 +/- 17.4% in parotid and submandibular glands, respectively. In contrast, in amifostine-treated rabbits parenchymal function was not significantly reduced. Histopathologically, marked lipomatosis was observed in control animals but was negligible in amifostine-treated animals. In control patients, salivary gland function was significantly (p < 0.001) reduced by 40.2 +/- 14.1% and 39.9 +/- 15.3% in parotid and submandibular glands, respectively, three months after HD-RIT, and 11 patients developed xerostomia. In 25 amifostine-treated patients, salivary gland function was not significantly reduced (p = 0.691), and xerostomia did not occur. Thus, parenchymal damage in salivary glands induced by high-dose radioiodine therapy can be reduced significantly by amifostine. This may improve quality of life of patients with differentiated thyroid cancer.

[Hemodynamic-kinetic controlled extracorporeal circulation in heart surgery]. / Hämodynamisch-kinetikgesteuerte extrakorporale Zirkulation in der Herzchirurgie.

Mimicking the physiological characteristics of the circulatory system, pulsatile bloodflow has also been introduced into extracorporeal perfusion to avoid known postoperative complications. In a mathematical consideration of the situation bloodflow is seen as a function of time F(t) for approximately constant vessel diameter over a given time. The kinetic energy of a column of blood produced by the heart-lung machine is transmitted directly to the arterial circulation via the aorta. The nature of the energy release can give rise to both positive (organ perfusion) and negative (damage to endothelium) effects. This study investigates how this energy release can be optimised, using the following experimental approach. A Doppler flow-measuring probe is placed on the ascending aorta to monitor the extracorporeal circulation. At the same time, the blood pressure is measured and converted to a pressure-flow curve via an A/D converter. On the basis of the parameters thus obtained, the energy released by the heart-lung machine is calculated. By regulating the functional parameters of a new generation of heart-lung machines, the bloodflow can then be adapted to the physiological requirements. Within the pulse period (cycle) a 20% rise phase ending in a slightly increasing plateau is established. The energy increase within a cycle should not exceed 150 joules. To optimize the mode of functioning of the heart-lung machine, we introduced the "energy-equivalent pressure" (EEP). Adaptation of the EEP to the physiological conditions required a basic flow of 60% at a pulse rate of 60/min and a pulse duration of 35% within the pulsatile flow interval.