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  • QUANTIFICATION  (4)
  • 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: 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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  • 3
    Keywords: EMPHYSEMA ; QUANTIFICATION ; DISEASE ; MORTALITY ; FUNCTION TESTS ; LUNG-VOLUMES ; STANDARDIZATION ; pirfenidone ; QUANTITATIVE CT INDEXES ; PHYSIOLOGICAL IMPAIRMENT
    Abstract: OBJECTIVES: To describe changes over time in extent of idiopathic pulmonary fibrosis (IPF) at multidetector computed tomography (MDCT) assessed by semi-quantitative visual scores (VSs) and fully automatic histogram-based quantitative evaluation and to test the relationship between these two methods of quantification. METHODS: Forty IPF patients (median age: 70 y, interquartile: 62-75 years; M:F, 33:7) that underwent 2 MDCT at different time points with a median interval of 13 months (interquartile: 10-17 months) were retrospectively evaluated. In-house software YACTA quantified automatically lung density histogram (10th-90th percentile in 5th percentile steps). Longitudinal changes in VSs and in the percentiles of attenuation histogram were obtained in 20 untreated patients and 20 patients treated with pirfenidone. Pearson correlation analysis was used to test the relationship between VSs and selected percentiles. RESULTS: In follow-up MDCT, visual overall extent of parenchymal abnormalities (OE) increased in median by 5 %/year (interquartile: 0 %/y; +11 %/y). Substantial difference was found between treated and untreated patients in HU changes of the 40th and of the 80th percentiles of density histogram. Correlation analysis between VSs and selected percentiles showed higher correlation between the changes (Delta) in OE and Delta 40th percentile (r=0.69; p〈0.001) as compared to Delta 80th percentile (r=0.58; p〈0.001); closer correlation was found between Delta ground-glass extent and Delta 40th percentile (r=0.66, p〈0.001) as compared to Delta 80th percentile (r=0.47, p=0.002), while the Delta reticulations correlated better with the Delta 80th percentile (r=0.56, p〈0.001) in comparison to Delta 40th percentile (r=0.43, p=0.003). CONCLUSIONS: There is a relevant and fully automatically measurable difference at MDCT in VSs and in histogram analysis at one year follow-up of IPF patients, whether treated or untreated: Delta 40th percentile might reflect the change in overall extent of lung abnormalities, notably of ground-glass pattern; furthermore Delta 80th percentile might reveal the course of reticular opacities.
    Type of Publication: Journal article published
    PubMed ID: 26110421
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  • 4
    Keywords: tumor ; AGENTS ; BLOOD ; Germany ; IN-VIVO ; MODEL ; PERFUSION ; THERAPY ; VIVO ; imaging ; QUANTIFICATION ; VOLUME ; liver ; TISSUE ; TIME ; BLOOD-FLOW ; INDEX ; CONTRAST ; blood flow ; CONTRAST AGENT ; FLOW ; INJECTION ; BIOLOGY ; metastases ; US ; PARAMETERS ; tomography ; KINETICS ; LIVER METASTASES ; CONTRAST AGENTS ; POWER DOPPLER SONOGRAPHY ; INDUCED DESTRUCTION ; AGENT ; TRANSIT-TIME ; DESTRUCTION ; REAL-TIME ; tissue viability ; OCT ; ENHANCED SONOGRAPHY ; HEPATIC METASTASES ; HEPATIC PERFUSION ; low-MI ultrasound ; MATHEMATICAL-MODEL ; quantification of perfusion ; replenishment kinetics ; TUMOR PERFUSION ; ultrasound contrast agent
    Abstract: Low-MI (mechanical index) ultrasound allows real-time observation of replenishment kinetics after destruction ("flash") of ultrasound contrast agents (USCA). We developed an examination protocol and a mathematical model to quantify perfusion of liver tissue and hepatic metastases. Using a modified multivessel model, we attempted a consistent, physiological description of microbubble replenishment in liver tissue. Perfusion parameters were calculated, separately for the arterial and portal venous phase of liver perfusion, using an i.v. bolus injection of 2 x 2.4 mL SonoVue(R). The model was evaluated for 10 examinations of liver metastases using flash/low-MI imaging. In contrast to the established, exponential model, the new model consistently describes the sigmoid replenishment of USCA measured in vivo, using flash/low-MI imaging. Parameters for blood volume, blood velocity and blood flow in liver tissue and metastases can be calculated during the arterial and the portal venous phase after a CA bolus injection. The median arterial perfusion in the examined liver metastases was more than 2.5 times higher than in normal liver tissue, whereas the median perfusion during the portal venous phase was more than five times higher in the liver tissue than that in metastases. Microbubble replenishment measured with flash/low-MI US techniques can be consistently analyzed using the multivessel model, even after a bolus injection of USCA. This allows for the quantification of perfusion of liver tissue and hepatic metastases and provides promising parameters of tissue viability and tumor characterization. (C) 2004 World Federation for Ultrasound in Medicine Biology
    Type of Publication: Journal article published
    PubMed ID: 15582235
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