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  • COMPUTED-TOMOGRAPHY  (3)
Keywords
  • 1
    Keywords: measurement ; ANGIOGENESIS ; Germany ; PERFUSION ; CLASSIFICATION ; CT ; imaging ; INFORMATION ; QUANTIFICATION ; liver ; TISSUE ; TUMORS ; computed tomography ; PATIENT ; BLOOD-FLOW ; INDEX ; primary ; INJECTION ; SIGNAL ; LESIONS ; PATTERNS ; DIFFERENCE ; metastases ; US ; tomography ; COMPUTED-TOMOGRAPHY ; LIVER METASTASES ; POWER DOPPLER SONOGRAPHY ; VASCULARIZATION ; contrast-enhanced ultrasound,liver metastases,arterial perfusion,low-MI imaging,SonoVue ; MICROBUBBLE CONTRAST ; SHU 508A
    Abstract: Rationale and Objectives: We investigated whether observing the arterial vascularization of liver metastases by contrast-enhanced ultrasound with low mechanical index (low-MI) imaging offers additional diagnostic information for the characterization of the liver lesions.Methods: Twenty nine patients with untreated liver metastases of different primaries were examined. Measurements were performed using a low frame rate, low-MI pulse inversion technique after injection of 2.4 mL SonoVue. The relative maximum signal intensity of the liver lesions related to the normal liver tissue was quantified. Ultrasound findings were compared with contrast-enhanced, dual-phase computed tomography (CT) using a pattern-based classification scheme.Results: Compared with contrast-enhanced CT, this modality better detects arterial perfusion. Metastases, even those usually considered hypovascularized, often showed homogeneous enhancement (66%) and higher arterial vascularization than normal liver tissue. CT did not show a comparable vascularization pattern (P 〈 0.001) or any similarly early signal intensity (P 〈 0.001).Conclusions: Contrast-enhanced CT may not be able to visualize short-lasting but large differences of the arterial perfusion of liver metastases, as does contrast-enhanced low-MI ultrasound. This offers new methods for their characterization and for monitoring of therapeutic effects
    Type of Publication: Journal article published
    PubMed ID: 15021325
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  • 2
    Keywords: CANCER ; tumor ; carcinoma ; Germany ; LUNG ; PERFUSION ; THERAPY ; CT ; DENSITY ; LUNG-CANCER ; NEW-YORK ; TUMORS ; PATIENT ; CONTRAST ; INJECTION ; treatment ; DIFFERENCE ; REGION ; REGIONS ; LOCALIZATION ; PARAMETERS ; tomography ; CARCINOMAS ; COMPUTED-TOMOGRAPHY ; PET ; lung neoplasms ; PULMONARY ; DYNAMIC CT ; X-ray computed
    Abstract: Advanced bronchial carcinomas by means of perfusion and peak enhancement using dynamic contrast-enhanced multislice CT are characterized. Twenty-four patients with advanced bronchial carcinoma were examined. During breathhold, after injection of a contrast-medium (CM), 25 scans were performed (I scan/s) at a fixed table position. Density-time curves were evaluated from regions of interest of the whole tumor and high- and low-enhancing tumor areas. Perfusion and peak enhancement were calculated using the maximum-slope method of Miles and compared with size, localization (central or peripheral) and histology. Perfusion of large tumors (〉50 cm(3)) averaged over both the whole tumor (P=0.001) and the highest enhancing area (P=0.003) was significantly lower than that of smaller ones. Independent of size, central carcinomas had a significantly (P=0.04) lower perfusion (mean 27.9 ml/min/100 g) than peripheral ones (mean 66.5 ml/min/100 9). In contrast, peak enhancement of central and peripheral carcinomas was not significantly different. Between non-small-cell lung cancers and small-cell lung cancers, no significant differences were observed in both parameters. In seven tumors, density increase after CM administration started earlier than in the aorta, indicating considerable blood supply from pulmonary vessels. Tumor perfusion was dependent on tumor size and localization, but not on histology. Furthermore, perfusion CT disclosed blood supply from both pulmonary and/or bronchial vessels in some tumors
    Type of Publication: Journal article published
    PubMed ID: 15029450
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  • 3
    Keywords: Germany ; LUNG ; CT ; EMPHYSEMA ; HIGH-RESOLUTION CT ; QUANTIFICATION ; VOLUME ; PATIENT ; IMPACT ; REDUCTION ; SIMULATION ; PARAMETERS ; COMPUTED-TOMOGRAPHY ; OBSTRUCTIVE PULMONARY-DISEASE ; THIN-SECTION CT ; HELICAL CT ; RE ; multidetector CT ; LUNG-VOLUME ; low dose ; MULTISLICE CT ; 3-dimensional quantitative volumetric analysis ; ALPHA-1-ANTITRYPSIN DEFICIENCY ; dose simulation ; LUNG DENSITY-MEASUREMENTS ; MACROSCOPIC MORPHOMETRY ; multidetector computed tomography ; VOLUME REDUCTION
    Abstract: Purpose: Quantitative evaluation of the lung parenchyma might be impaired or unreliable by use of reduced-dose CT protocols. Aim of the study was to define the threshold where reduced dose has significant impact on quantitative emphysema parameters. Materials and Methods: Thirty patients with severe centrilobular emphysema underwent multidetector computed tomography (120 kV, 150 mAs). Original CT raw data were simulated using 10 mAs settings (10-100 SlMmAs). Quantitative analysis provided lung volume, emphysema volume, emphysema index, mean lung density, and 4 emphysema volume classes. Simulated low-dose results were compared with original acquisition. Results: Emphysema index showed no clinical relevant variation down to 30 SlMmAs. The large emphysema volume class was significantly different below 50 SlMmAs. The intermediate and small classes showed an overproportional variation below 50 SlMmAs. Conclusions: Dose reduction down to 30 SlMmAs is possible for clinical routine. Settings below 50 SlMmAs significantly alter the indetailed 3-dimensional emphysema quantification
    Type of Publication: Journal article published
    PubMed ID: 16778622
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