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G Antoch

Publications and source records attributed to G Antoch.

At least 19 recordsLinked to original sources
PubMed2006

[Whole-body MR diagnostic concepts].

The term whole-body magnetic resonance imaging (MRI) covers a whole series of different MRI techniques that can be used for detecting various diseases. Whole-body magnetic resonance angiography facilitates the visualization of the entire arterial system from head to toe with the exception of the coronary arteries. Whole-body MRA is clinically used for therapy planning in patients with multiple stenoses and may be able to be used in the future as a screening method for high risk populations, for example in patients with coronary heart disease. Whole-body MRI can replace skeletal scintigraphy in the detection of bone marrow metastases by using fluid-sensitive sequences. Fast contrast-enhanced sequences can be used as an alternative approach in the search for tumors. Whole-body MRI can even be superior to a combination of positron-emission tomography and computed tomography in the detection of distant metastases. This article presents the recent developments in whole-body MRI and its established indications, which in the future might lead to a change in the paradigm for the diagnostic work-up of many diseases.

Humans↗
PubMed2006

[Radiofrequency ablation of malignant liver tumors: use of a volumetric necrosis-tumor ratio for local control].

PURPOSE: Sufficient safety margins are essential for preventing local tumor recurrence after radiofrequency ablation RFA of malignant liver tumors. The aim was to determine the initial tumor volume, ablation necrosis volume, and the necrosis-tumor quotient in order to compare these parameters with the rate of local control during follow-up. MATERIALS AND METHODS: 35 patients with 53 tumor nodules (29 colorectal metastases and 24 HCC nodules) were enrolled. RFA procedures were performed under CT guidance with intravenous conscious sedation. Tumor volumes were measured based on CT data sets and the necrosis volume was assessed using the sum-of-area method. A volumetric necrosis/tumor quotient (NTQ) was calculated for all lesions. Follow-up examinations were performed after 3, 6, and 12 months and then on a yearly basis to identify local recurrent tumors. RESULTS: The CRC metastases and HCC nodules had a median tumor volume of 8.3 ml and 7.4 ml, respectively. The mean ablation volumes were 37.6 ml and 29.5 ml, respectively. This resulted in a median NTQ of 3.9 for metastases and 3.4 for HCC. The follow-up (mean time 18 months) revealed local tumor recurrence in 16 of 29 (55 %) metastases and 10 of 24 (42 %) HCC nodules. In lesions with local recurrence, the initial tumor volume was significantly greater and the NTQ was significantly smaller. A threshold value of 3.4 for NTQ has the highest predictive value for local tumor recurrence. CONCLUSION: The volumetric necrosis/tumor quotient NTQ makes it possible to predict the local outcome and can be used for the planning of additional therapy.

Aged↗
PubMed2005

Whole body positron emission tomography/computed tomography (PET/CT) tumour staging with integrated PET/CT colonography: technical feasibility and first experiences in patients with colorectal cancer.

AIM: The aim of this study was to implement an imaging protocol for positron emission tomography/computed tomography (PET/CT) colonography and to combine this protocol with whole body PET/CT tumour staging for a single whole body examination for routine clinical use. SUBJECTS AND METHODS: A whole body PET/CT protocol for tumour staging and a protocol for PET/CT colonography were integrated into one examination. Fourteen prospective patients with suspected colorectal cancer underwent whole body PET/CT after aqueous bowel distension and pharmacological bowel relaxation. Colonoscopy and histopathology served as the standards of reference in all patients. RESULTS: The modified PET/CT examination detected all but one lesion in the colon. One additional lesion was detected in a patient with incomplete colonoscopy due to high grade luminal stenosis. One polyp with malignant conversion was identified with the modified PET/CT protocol. PET/CT colonography proved accurate in local lymph node staging and staged nine out of 11 patients correctly. Six additional extracolonic tumour sites were detected based on the whole body staging approach. CONCLUSION: Whole body PET/CT with integrated colonography is technically feasible for whole body staging in patients with colorectal cancer. Based on these initial diagnostic experiences, this integrated protocol may be of substantial benefit in staging patients with colorectal cancer, focusing on patients with incomplete colonoscopy and those with small synchronous bowel lesions.

Aged↗
PubMed2005

How much CT do we need for PEt/CT? A radiologist's perspective.

In clinical practice different CT imaging protocols are implemented within combined PET/CT acquisition protocols. From a radiologist's perspective the full potential of PET/ CT for oncology imaging can be used only by exploring the full capacity of the CT. This mandates the use of oral and intravenous contrast material as well as a CT image quality which proves diagnostically sufficient by radiology standards. The integration of a fully-diagnostic CT exam portion into combined PET/CT is demanding and requires adjustments of CT acquisition protocols. Given the use of the CT for CT-based attenuation correction potential PET/CT image artifacts have to be considered as well. In this paper we review radiological perspectives on PET/CT imaging.

Contraindications↗
PubMed2004

Value of (124)I-PET/CT in staging of patients with differentiated thyroid cancer.

The aim of this study is to evaluate the clinical significance of (124)I positron emission tomography (PET) using a combined PET/CT tomograph in patients with differentiated thyroid carcinoma and to compare the PET/CT results with (131)I whole-body scintigraphy (WBS), dedicated PET and CT alone. Twelve thyroid cancer patients were referred for diagnostic workup and entered complete clinical evaluation, including histology, cytology, thyroglobulin level, ultrasonography, fluorine-18 fluorodeoxyglucose (FDG)-PET, FDG-PET/CT and CT. Lesion-based evaluation showed a lesion delectability of 56, 87 and 100% for CT, (124)I-PET, and combined (124)I-PET/CT imaging, respectively. Lesion delectability of (131)I-WBS was 83%. We conclude that (124)I-PET/CT imaging is a promising technique to improve treatment planning in thyroid cancer. It is particularly valuable in patients suffering from advanced differentiated thyroid cancer prior to radio-iodine therapy and in patients with suspected recurrence and potential metastatic disease.

Adult↗
PubMed2004

[Whole-body tumor staging: MRI or FDG-PET/CT?].

Technical innovations such as the availability of movable patient platforms and the introduction of 32-channel systems have made whole-body MRI for tumor staging feasible. In addition, the development of dual-modality PET/CT systems offers the opportunity to perform anatometabolic tumor staging with whole-body coverage in a single session. Based on an increase in patient survival when applying a stage-adapted therapy in different malignant diseases the relevant question relates to the accuracies of whole-body MRI and whole-body PET/CT for TNM staging. This review article addresses whole-body tumor staging with MRI and FDG-PET/CT with special emphasis on diagnostic accuracies for staging different malignant diseases.

Aged↗
PubMed2004

[Principles of PET/CT and clinical application].

Medicine today imposes high demands on diagnosing disease. Techniques should be preferably noninvasive, identify the disease at an early stage, and be quick and accurate. Frequently, these demands can only be met by employing various diagnostic modalities. Consequently, the integration of two imaging modalities, such as the combination of PET and CT, increases the quality of coregistration and facilitates a timely diagnosis. However, complex imaging procedures require a judicious choice of the areas of application. If, for example, both PET and CT are indicated then a combined PET/CT exam results in improved diagnosis, whereby the actual benefit will depend upon the clinical problem. Typically we expect an advantage of 10% with PET/CT compared to separate examinations with CT and PET. In addition, PET/CT allows for new indications and applications, which cannot be performed satisfactorily with independent examinations and retrospective image alignment. One example is the application of PET/CT in radiation therapy planning.

Artifacts↗
PubMed2004

[Value of pelvic MRI in the preoperative diagnosis of endometriosis].

PURPOSE: To determine the value of magnetic resonance imaging (MRI) of the pelvis in the preoperative diagnosis of endometriosis. MATERIALS AND METHODS: Over a period of 8 months, preoperative MRI of the pelvis were obtained in 13 patients with suspected endometriosis (mean patient age 34.6 years; range 25 - 47 years). RESULTS: In 9 of 13 patients (69 %), the diagnosis of endometriosis was made by MRI and confirmed by laparoscopy in 8 cases. In 2 of 13 patients, endometriotic lesions were detectable by laparoscopy only. In the remaining 2 patients, no endometriosis was visible on MRI or by laparoscopy. MRI was able to visualize a total of 19 endometriotic lesions, with 14 (74 %) confirmed by histopathologic examination following laparoscopy. Five of these 19 lesions (26 %) visible on MRI were not seen by laparoscopy. Using laparoscopy and subsequent histopathologic examination, 27 endometriotic lesions were diagnosed, with 13 (48 %) not seen on the preoperative MRI. CONCLUSION: MRI and laparoscopy are complementary diagnostic tools that will best document the full extent of endometriosis when combined. MRI can visualize additional lesions inaccessible to laparoscopy. Thus, MRI of the pelvis should used preoperatively for surgical treatment planning.

Adult↗
PubMed2003

FDG-PET/CT in re-staging of patients with lymphoma.

The aim of this study was to evaluate the clinical significance of combined fluorine-18 fluorodeoxyglucose positron emission tomography and computed tomography (FDG-PET/CT) in patients with lymphoma, and to compare the FDG-PET/CT staging results with those of FDG-PET and CT alone. Twenty-seven patients were studied. Each patient had clinical follow-up for >12 months and entered complete follow-up evaluation. Patient-based evaluation showed a sensitivity of 78% for CT alone, 86% for FDG-PET alone, 93% for CT and FDG-PET read side by side, and 93% for combined FDG-PET/CT imaging. Region-based evaluation showed a sensitivity for regional lymph node involvement of 61%, 78%, 91% and 96% respectively. FDG-PET/CT imaging is superior to CT alone ( P=0.02) and has additional benefit over FDG-PET alone due to exact anatomical localisation. We conclude that FDG-PET/CT imaging is accurate in re-staging lymphoma and offers advantages over separate FDG-PET and CT imaging.

Adult↗
PubMed2003

Combined PET/CT with iodine-124 in diagnosis of spread metastatic thyroid carcinoma: a case report.

Iodine-124 positron emission tomography (PET) is a useful 3D imaging technique for diagnosis and management of thyroid diseases. The difficulty in interpretation of the PET scans with highly selective tracers, such as iodine-124, is the lack of identifiable anatomical structures, so an accurate anatomical localization of foci presenting abnormal uptake is problematic. Consequently, a combined PET/CT scanner can resolve these difficulties by co-registering PET and CT data in a single session allowing a correlation of functional and morphologic imaging. A case is presented where iodine-124 produced by a clinical cyclotron and FDG were used to acquire images with a combined PET/CT scanner for clinical staging. On the basis of the PET/CT exams the treatment of the patient was modified.

Adenocarcinoma, Follicular↗
PubMed2003

Diagnosis in medullary thyroid cancer with [18F]FDG-PET and improvement using a combined PET/CT scanner.

Today, positron emission tomography (PET) investigation using fluorodeoxyglucose (FDG) is the most sensitive and specific single modality established for localizing metastases of medullary thyroid cancer (MTC). Even at calcitonin serum levels below 20 pg/ml, tumour localization may be successful in individual cases. However, especially in such early tumour stages, the morphological correlation using PET is unsatisfactory. With the newly available fixed combination of PET and computed tomography (PET/CT), this drawback can be overcome as PET/CT allows a point-by-point correlation of pathological function with morphological structure. Conventional PET alone yielded an approx 80 % sensitivity and specificity in MTC: a result that will be surpassed by the combined PET/CT scanner.

Fluorodeoxyglucose F18↗
PubMed2003

Diagnosis of labia metastasis by F-18 FDG PET and CT fusion imaging in sarcoma follow-up.

ABSTRACT A 32-year-old woman with a history of pelvic sarcoma underwent whole-body fluorine-18 fluorodeoxyglucose positron emission tomography (PET) and computed tomographic (CT) fusion imaging for restaging after primary surgery and adjuvant combined radiation and chemotherapy. Interpreting the PET images alone showed an area of focal tracer accumulation in the pelvic floor and was interpreted as being secondary to urine contamination. Image fusion with fully coregistered CT scans showed a localized site of increased uptake from a metastasis to the labia, which was confirmed by biopsy. The presented case illustrates the usefulness of combined PET/CT fusion imaging to overcome some pitfalls of PET imaging alone (eg, differentiating malignant tumor from pooling of tracer in the genitourinary tract or contamination).

Adult↗