[Is ceCT necessary beyond FDG-PET/CT for primary staging in Hodgkin lymphoma?]. / Szükséges-e Hodgkin-limfóma primer stádium-megállapításához FDG-PET/CT mellett iv. ka. CT elvégzése is?

INTRODUCTION: Several study supported that 18F-Fluoro-deoxy-glucose (FDG) positron emission tomography/computer tomography with low dose CT (standard PET/CT) is more accurate than contrast-enhanced CT (ceCT) in the primary staging of Hodgkin disease. AIM: The authors compared the accuracy of these examinations with this indication in their practice, and analysed the added value of ceCT which was performed as a supplement to standard PET/CT. METHOD: Twenty-eight patients were categorized based on ceCT, single standard PET/CT and standard PET/CT with ceCT. RESULTS: Twenty-four patients were in the same disease-stage based on all methods. Disease was upstaged by standard PET/CT compared to ceCT in 4 patients. There was no change in stage when comparing standard PET/CT and standard PET/CT with ceCT. CONCLUSIONS: Standard PET/CT is more accurate than ceCT in the primary staging of Hodgkin disease. The authors established that it is not reasonable to supplement standard PET/CT with ceCT in this indication.

[Surgical treatment of resistant epilepsy, caused by hemispherical dysgenesis--case report]. / Hemisphaerialis dysgenesis okozta rezisztens epilepszia mûtéti kezelése--esetismertetés.

A part of patients with the therapy resistant epilepsy can be cured by surgical interventions. The more concordant the presurgical evaluation data, the better prognosis the patient has postoperatively. In case of discordant examination data, multimodal evaluation or case-specific decision might be successful. We report on a five-year-old boy with bilateral (left-dominated) cortical dysplasia and therapy resistant epilepsy. The ictal EEG did not help to localize the seizure onset zone, semiology had little lateralization value; however, FDG-PET showed left hemispheric hypermetabolism. The child became almost seizure-free and showed improved development after left-sided hemispherotomy.

Effects of vinpocetine on the redistribution of cerebral blood flow and glucose metabolism in chronic ischemic stroke patients: a PET study.

The pharmacological effects of the neuroprotective drug vinpocetine, administered intravenously in a 14-day long treatment regime, on the cerebral blood flow and cerebral glucose metabolism in chronic ischemic stroke patients (n=13) were studied with positron emission tomography in a double-blind design. The regional and global cerebral metabolic rates of glucose (CMRglc) and cerebral blood flow (CBF) as well as vital physiological parameters, clinical performance scales, and transcranial Doppler parameters were measured before and after the treatment period in patient groups treated with daily intravenous infusion with or without vinpocetine. While the global CMRglc values did not change markedly as a result of the infusion treatment with (n=6) or without (n=7) vinpocetine, the global CBF increased and regional CMRglc and CBF values showed marked changes in several brain structures in both cases, with more accentuated changes when the infusion contained vinpocetine. In the latter case the highest rCBF changes were observed in those structures in which the highest regional uptake of labelled vinpocetine was measured in other PET studies (thalamus and caudate nucleus: increases amounting to 36% and 37%, respectively). The findings indicate that a 2-week long intravenous vinpocetine treatment can contribute effectively to the redistribution of rCBF in chronic ischemic stroke patients. The effects are most pronounced in those brain regions with the highest uptake of the drug.

Microscopic colitis: a retrospective study of clinical presentation in 53 patients.

AIM: To evaluate the relationship between symptoms and microscopic colitis (MC) subtypes: to test whether collagenous colitis (CC) and/or lymphocytic colitis (LC) might be related to both constipation and diarrhea. METHODS: A cohort of patients with independently confirmed typical histopathological changes was investigated. Fifty-three patients with histologically proved MC (46 with CC, 7 with LC) were included. The existence of diarrhea or constipation and the co-existence of autoimmune diseases were also investigated and all data were retrospectively analyzed. RESULTS: Twenty-three (43.39%) of MC patients had chronic constipation (20 in CC, 3 in LC patients). Twenty-four (45.28%) of MC patients had autoimmune disease and the diagnosis of autoimmune disease was always prior to MC. Sjögren's syndrome was associated only with the constipation subgroup. CONCLUSION: The Janus face of MC resembles the subgroups of irritable bowel syndrome. The co-existence of autoimmune diseases and MC is confirmed in both the constipation and diarrhea subgroups.

Correlation of the value of 18F-FDG uptake, described by SUVmax, SUVavg, metabolic tumour volume and total lesion glycolysis, to clinicopathological prognostic factors and biological subtypes in breast cancer.

OBJECTIVE: The aim of this study was to observe the relationships between different metabolic parameters and clinicopathological features (CPFs) or immunohistochemically defined biological subtypes (IHC-BS) in breast cancer. MATERIALS AND METHODS: Eighty-two women (83 lesions, tumour size>15 mm) underwent PET/computed tomography imaging after a core biopsy. Maximum and average standardized uptake values (SUVmax, SUVavg), metabolic tumour volume (MTV) and total lesion glycolysis (TLG) in the primary tumour were calculated and compared with CPFs and IHC-BS. Tumours with oestrogen receptor (ER) positivity were separately investigated in relation to their progesterone receptor (PR) status. RESULTS: Significant correlation was found between all metabolic parameters and high nuclear grade or ER status or IHC-BS. All parameters were higher in PR(-) and triple-negative cases than in PR(+) and non-triple-negative tumours, and the correlation was significant for most of the metabolic parameters (except for SUVavg in the case of PR status and MTV in the case of triple negativity). Significant correlation was found only for SUVmax regarding the human epidermal growth factor receptor 2 (HER2) status. There was moderate correlation between the Ki67 expression and the SUVmax or SUVavg. All metabolic parameters were higher in ER(+)/PR(-)/HER2(-) lesions compared with ER(+)/PR(+)/HER2(-) cancers. However, ER(+)/PR(-)/HER2(+) tumours had lower SUVmax and SUVavg compared with ER(+)/PR(+)/HER2(+) lesions. CONCLUSION: Our study confirms that the fluorine-18 fluorodeoxyglucose uptake in primary tumour is associated with distinct CPFs or IHC-BS in breast cancer. SUVmax may reflect tumour metabolism more reliably compared with SUVavg, MTV or total lesion glycolysis. Our preliminary results suggest different biological properties in ER(+) tumours with different PR statuses.

18F-FDG PET detection of lymph node metastases in medullary thyroid carcinoma.

UNLABELLED: Postsurgically elevated or increasing serum calcitonin levels strongly suggest the presence of residual or recurrent medullary thyroid carcinoma (MTC). Several imaging modalities (sonography, MRI, CT, scintigraphy with different types of radiolabeled ligands, etc.) are routinely used in an attempt to localize tumorous tissue, but such efforts often fail. In the search for a more reliable method, 18F-FDG PET was applied to detect tumor tissue of residual or recurrent MTC. METHODS: Forty patients with a postoperatively elevated plasma calcitonin level were included. These patients underwent routine diagnostic imaging procedures (CT, MRI, and 131I-metaiodobenzylguanidine [MIBG] whole-body planar scintigraphy or SPECT) and 18F-FDG PET examinations. Two independent experts visually analyzed the images provided by each method to detect pathologic lesions. Lymph nodes of > or = 1 cm in short diameter that were detected by radiologic methods were considered to be pathologic. 18F-FDG accumulation with a sharp contour reported by both independent observers was similarly regarded as pathologic. RESULTS: PET detected 270 foci with a high tracer accumulation, whereas only 116 lesions were detected by MRI and 141 by CT. The numbers of such foci determined by PET, MRI, and CT were 98, 34, and 34, respectively, in the neck; 25, 5, and 6, respectively, in the supraclavicular regions; and 117, 35, and 39, respectively, in the mediastinum. 131I-MIBG scintigraphy findings were positive for only 3 patients. CONCLUSION: For MTC patients with a postoperatively elevated plasma tumor marker level, PET was more sensitive and superior in localizing tumorous lymph node involvement than were the other imaging modalities, especially in the cervical, supraclavicular, and mediastinal lymphatic regions.

PET identifies transitional metabolic change in the spinal cord following a subthreshold dose of irradiation.

Positron emission tomographic (PET) investigations were performed to obtain in vivo information on symptomless radiation-induced pathological changes in the human spinal cord. PET investigations were carried out prior to radiotherapy and during the regular follow-up in an early hypopharyngeal cancer patient (the spinal cord was irradiated with a biologically effective dose of 80 Gy2), with [18F]fluorodeoxyglucose (FDG), [11C]methionine and [15O]butanol as tracers; radiosensitivity and electroneuronographic (ENG) studies were also performed. A very low background FDG accumulation (mean standardized uptake values, i.e. SUV: 0.84) was observed in the spinal cord before the initiation of radiotherapy. An increased FDG uptake was measured 2 months after the completion of radiotherapy (mean SUV: 1.69), followed by a fall-off, as measured 7 months later (mean SUV: 1.21). By 44 months after completion of irradiation, the FDG accumulation in the irradiated segments of the spinal cord had decreased to a level very close to the initial value (mean SUV: 1.11). The simultaneous [15O]butanol uptake results demonstrated a set of perfusion changes similar to those observed in connection with the FDG accumulation. The patient exhibited an extremely low [11C]methionine uptake within the irradiated and the nonirradiated spinal cord during the clinical course. She has not had any neurological symptoms, and the results of central ENG measurements before radiotherapy and 2 months following its completion proved normal. Radiobiological investigations did not reveal unequivocal signs of an increased radiosensitivity. A transitory increased spinal cord FDG uptake following radiotherapy may be related to the posttherapeutic mild inflammatory and regenerative processes. The normal [11C]methionine accumulation observed is strong evidence against intensive cell proliferation. The high degree of normalization of the temporarily increased FDG uptake of the irradiated spinal cord segments by 44 months is in good agreement with the results of monkey studies, which demonstrated a nearly complete recovery from radiation-induced spinal cord injury.

The possible role of F-18 FDG positron emission tomography in the differential diagnosis of focal pancreatic lesions.

PURPOSE: To compare the diagnostic values of different methods for the differentiation of malignant from benign pancreatic lesions. METHODS: In 22 patients with focal pancreatic lesions, the carbohydrate antigen (CA) 19-9 level was measured; abdominal ultrasound (US), computed tomography (CT), endoscopic retrograde cholangiopancreatography (ERCP), and F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) were performed; and the value of these methods were analyzed for their use in cancer diagnosis. RESULTS: Malignant lesions were identified in six patients and verified by surgery or clinical follow-up. The CA 19-9 level was elevated in four of the five patients examined (sensitivity, 80%). In all six cases, US and CT revealed hypoechogenic and hypodense areas (sensitivity, 100%). In one patient, ERCP was unsuccessful but yielded true-positive results in three others (sensitivity, 60%). The sensitivity of FDG PET was 100%. Sixteen focal cases of pancreatic disease proved to be benign. The CA 19-9 level was elevated in four of them (specificity, 73%). Hypoechogenic and hypodense areas were evident on US and CT in eight patients. The specificity of CT was 50% (8 of 16 cases). The specificity of US was 47% (7 of 15 cases). The specificity of successful ERCP was 92%. Fourteen negative FDG-PET results were truly negative. In two patients, however, the PET findings proved to be falsely positive (specificity, 88%). CONCLUSIONS: FDG-PET is an effective tool to differentiate malignant from benign focal pancreatic lesions. In persons with focal pancreatic hypoechogenic or hypodense lesions detected by CT or US and an elevated CA 19-9 level, FDG PET should be the next step in the diagnostic strategy.

[Standard PET examination protocols]. / Standard PET-vizsgálati protokollok.

The authors briefly review the most important components, concepts and procedures of the PET method. They present the basic examination protocols and the special features of each type of investigation. A short summary of issues relating to the daily routine, the image processing and visualization as well as the data archiving is also included.

[FDG PET scan of metastases in recurrent medullary carcinoma of the thyroid gland]. / Recidív medullaris pajzsmirigydaganat metastasisainak FDG-PET-vizsgálata.

Searching for metastases of medullary thyroid cancer (MTC), FDG PET was applied. PET results were compared with those of conventional diagnostic imaging procedures. After primary treatment, 52 MTC patients with elevated serum tumor marker levels and/or general symptoms (diarrhoea/flush) underwent radiological (CT/MRI), 131-iodine labeled metaiodo-benzylguanidine (MIBG) whole-body scintigraphy and FDG PET investigations. At least one pathological lesion was detected in 49 patients by PET, 35 by CT, 32 by MRI and 3 by MIBG. FDG PET was far superior to the other methods in identifying metastases in the supradiaphragmatic lymphatic regions. In the follow-up of MTC patients, FDG PET was more sensitive in localizing tumorous LN involvement, especially in the cervical, supraclavicular and mediastinal lymphatic regions, compared to other imaging modalities.

[Detection of recurrent head and neck cancer with positron emission tomography]. / Fej-nyaki tumorok daganatkiújulásának megítélése pozitronemissziós tomográfia alkalmazásával.

Differentiation between recurrence and post-therapeutic lesions in patients with previously treated head and neck cancer can be a real diagnostic problem. The authors discuss the role of positron emission tomography in restaging of this disease by a retrospective analysis based on 20 scans of 17 patients. PET findings were correct in identifying tumors in 85% of patients (11/13) in the group of positive PET results. All negative PET findings (4/4) were also correct during the follow-up. PET results were validated in 88% (15/17) of the patients. In one case silent distant metastases were also detected. PET is a reliable method in restaging previously treated head and neck cancer patients as it can differentiate post-therapeutic changes from tumor relapse.

[Positron emission tomography in the investigation of malignant testicular tumors]. / Pozitronemissziós tomográfia a malignus heredaganatok vizsgálatában.

Thirty-three [18F]-FDG and ten [11C]-methionine (altogether 43) PET studies were performed in 37 (24 non-seminoma and 13 seminoma) patients. All results were assessed on the basis of histology (or cytology) or clinical follow-up. PET scan identified metastatic disease in 13 cases while 30 investigations resulted in a negative medical report. There were 3 false-positive cases and no false-negative results were obtained. The false-positive results were likely to occur due to FDG accumulation in benign lesions. There were no false-positive findings with the use of [11C]-methionine. Sensitivity, specificity and accuracy were 100%, 91% and 93%, respectively, using both tracers.

[The role of PET scan in the investigation of epileptic functional disorders]. / A PET helye az epilepsziás agyi múködészavar meghatározásában.

Systematic research is needed to evaluate the exact role of pathological factors in the determination of the extension of the hypometabolic area in partial epileptic patients. Together with structural damage, previous seizures, deafferentation and inhibitory mechanisms may contribute to the functional disorders. Benzodiazepine receptor studies showed that the density and binding ability of these receptors decreased in the area of epileptic functional disorder. Circumscribed hypermetabolism may appear during epileptic seizures or even more electrical discharges. The authors' PET studies aimed at presurgical evaluation showed that bilateral temporal hypometabolism occurred more frequently with right-sided seizure start. FDG-PET supported the localization of the pacemaker area both in temporal lobe epilepsies and in extratemporal epilepsies. This method proved instrumental in delineating the extension of the background pathology, too. The authors also demonstrated the strength of PET brain activation in mapping the hemispheric distribution of speech functions required in the planning of surgical interventions. The role of hippocampal sclerosis in temporal lobe hypometabolism was investigated and a short account is given of the observations relating to the relationship of hypermetabolism due to subclinical epileptic discharges and cognitive deficit symptoms.

[Use of positron emission tomography in psychiatry]. / A pozitronemissziós tomográfia pszichiátriai alkalmazása.

For the past years, substantial amount of experimental data has been published on the use of positron emission tomography in different psychiatric disorders. The different PET methods, which evaluate the whole-brain or regional metabolism, tissue perfusion or receptor density may help to identify the disorder specific changes in brain function and also better understand the underlying pathophysiology. In the clinical practice, PET plays an important role in the diagnosis and differential diagnosis of dementias and, presumably, in the near future the PET technique will be also extensively used in the clinical examination of other psychiatric disorders.

[The role of PET scan among cardiologic imaging methods]. / A metabolikus PET-vizsgálatok helye a kardiológiai képalkotó eljárások között.

The PET technique has been available for myocardial viability studies in Hungary since 1994. The early comparative results showed that FDG-PET identified more potentially reversible myocardial damages than [201Tl]-scintigraphy, defining the viability either by preserved metabolic activity of 50% or by metabolism-perfusion mismatch. According to the follow up of revascularized patients in our cases, FDG-PET had a positive predictive value for functional recovery at 80%. In our opinion, it is the detection of glucose metabolism that predicts with the greatest accuracy segments of hibernating myocardial tissue that will recover after revascularization. Unlike dobutamine echocardiography, PET can detect viable ventricular segments in the myocardium of lost contractile material often seen in the histological studies of chronically ischemic myocardium. The FDG-PET method can be regarded as the gold standard of myocardial viability.

[Cost-effective PET scans in oncology]. / Költséghatékony onkológiai PET-vizsgálatok.

The authors have reviewed the financial considerations of oncological FDG PET examinations by the guidelines of the Health Care Financing Administration (USA). By critical assessment of large number of clinical investigations, the cost-effectiveness of FDG PET scans has been confirmed in the following cases: differential diagnosis of solitary pulmonary nodule, diagnosis, staging and restaging of non-small cell lung cancer, colorectal cancer, malignant lymphomas, melanoma malignum, esophageal neoplasms and cancers of the head and neck. The role of this method in breast cancer is currently under intensive investigation. Due to the correct staging, PET examinations in these indications enable the clinicians to choose the optimal treatment ensuring the maximum probability of recovery and being cost-effective as unnecessary medical interventions become avoidable.

[The role of PET scan in the diagnosis of malignant melanoma]. / A PET jelentósége a melanoma malignum diagnosztikájában.

Comprehensive, accurate staging has a critical role in planning rational treatment strategies for patients with malignant melanoma (MM). In the present study the authors investigate the value of FDG PET in staging and restaging based on the investigation of 37 high-risk MM patients and compare the results with the one obtained by conventional imaging techniques (X-ray, US, CT, MR and bone scan). Thirty-nine whole body PET scans were carried out. The authors concluded that FDG PET had the highest sensitivity among the imaging methods in detecting distant metastases of MM.

[The role of FDG-PET scan in the diagnosis of pancreatic carcinoma]. / Az FDG-PET-vizsgálat értéke a pancreascarcinoma diagnosztikájában.

In 22 patients with focal pancreatic lesions, the values of different diagnostic modalities were analysed for the evaluation of malignancy. The CA 19-9 level was elevated in 4/5 malignant cases (sensitivity: 80%) and in 4/15 of benign cases (specificity: 73%). Hypodensity/hypoechogeneity was considered to be the characteristic sign of malignancy during CT/ultrasound (sensitivity: 100%, specificity: 50%/47%). ERCP was found to be specific but not sensitive enough and the rate of unsuccessful investigations was relatively high (4/22). The diagnostic value of FDG-PET was found to be superior to other diagnostic modalities (sensitivity 100%, specificity 88%). In cases with focal pancreatic hypoechogenic/hypodense lesions detected by CT or US in suspicion of malignancy, the FDG-PET should be the next step in the diagnostic strategy.

[PET and SPECT scans in autistic children]. / PET- és SPECT-vizsgálatok autista gyermekeken.

The authors have analyzed and compared the results of the 99mTc-ECD-SPECT and FDG-PET examinations, performed in alert state, of 12 children suffering from infantile (9 subjects) or atypical (3 subjects) autism. In addition to frontally increased FDG metabolism, a decreased blood flow with left-sided dominance was found bifrontally and bitemporally in the infantile form (perfusion-metabolism mismatch). The regional differences in cortical FDG uptake were not significant in atypical autism, although both the blood flow and the metabolism of the thalami were decreased. Based on the results, the authors suggest that, beyond the usually inconclusive structural (CT or MR) examinations, cerebral blood flow SPECT and metabolic FDG-PET investigations may be useful in classifying the disease.

[Cost-effective PET investigations in oncology]. / Költség-hatékony onkológiai PET-vizsgálatok.

The authors have reviewed the financial considerations of oncological FDG PET examinations by the guidelines of the Health Care Financing Administration (USA). By critical assessment of large number of clinical investigations,the cost-effectiveness of FDG PET scans has been confirmed in the following cases: differential diagnosis of solitary pulmonary nodule, diagnosis,staging and restaging of non-small cell lung cancer, colorectal cancer, malignant lymphomas, melanoma malignum, esophageal neoplasms and cancers of the head and neck. The role of this method in breast cancer is currently under intensive investigation. Due to the correct staging, PET examinations in these indications enable the clinicians to choose the optimal treatment ensuring the maximum probability of recovery and being cost-effective as unnecessary medical interventions become avoidable.