Multiple Arterial Phase Computed Tomography Examination to Improve Detection of Tumors in the Liver and Pancreas

Study Overview
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Brief Summary
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To examine inter-subject variations of optimal late arterial phase contrast-enhancement defined as the greatest difference in contrast attenuation of hepatocellular carcinoma (HCC) compared to background liver parenchyma resp. pancreatic lesions compared to pancreatic parenchyma. To evaluate which time-points best depict an optimal late arterial phase.

Detailed Description
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Background: Many previous studies have analyzed and proposed different strategies to achieve optimal contrast timing and enhancement in the late arterial phase to best depict arterialized lesions in the liver and hypoattenuating tumors in the pancreas(1-12). But even with the use of state-of-the-art protocols, inter-subject variations of optimal contrast enhancement in liver lesions and pancreas parenchyma are still very common. The aim of this study is to first analyze these alterations and to, secondly, use the newly gained knowledge to design a dose-neutral multiple arterial phase protocol. An optimized arterial phase protocol might improve the detection of hepatocellular carcinoma (HCC) and/or pancreatic adenocarcinoma. Purpose: To measure when the greatest difference in attenuation occurs in HCC compared to background liver parenchyma resp. in pancreatic lesions vs. pancreatic parenchyma. To describe the inter-subject variation of these enhancement times and to evaluate at which time-points an optimal late arterial phase can be achieved. The investigators will use the perfusion scanning technique, bolus-tracking and high body-weight-adjusted volumes of contrast media (CM). Anticipated results: The aim is to find the best time points for optimal CM-enhancement in HCC lesions and pancreas parenchyma. The results will show the extent of the inter-subject temporal enhancement differences and will be used to design an optimized late arterial phase protocol for clinical practice and future studies.

Official Title
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Low Dose Multi-arterial Phase CT Imaging for Improved Detection of Liver Tumors and Pancreatic Masses

Conditions
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Contrast Media, Computed Tomography, Imaging, Pancreatic Cancer, Hepatic Cancer

Intervention / Treatment
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* Diagnostic Test: Computed Tomography of the Abdomen


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients, who are scheduled for a multiphasic liver or pancreas CT because of known or suspected malignancy in the liver or pancreas. Exclusion Criteria: below 50 years of age, contrast media allergy or decreased kidney function

Ages Eligible for Study
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Minimum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Diagnostic Test: Computed Tomography of the Abdomen|Multi-phasic CT scan of the abdomen: 1 low dose unenhanced scan + 10 low dose arterial perfusion scans + 1 portal-venous phase scan + 1 delayed phase scan. Bolus-tracking threshold in abdominal aorta = 160 HU. Delay of first arterial scan 5 sec after bolus-tracking threshold has been reached; and then 1 scan every 3 sec until 35 sec after threshold. Contrast media (CM) protocol: fixed injection duration: 25 sec, body weight-adjusted CM volume: 750 mgI/kg bodyweight (max 80 kg women, 100kg men), Iomeron 400mgI/ml. Image-reconstruction: Motion-correction, noise-reduction and fusion of the best arterial time points to reconstruct one optimally timed early and one optimally timed late arterial phase.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Peak enhancement values measured in Hounsfield units(HU) in abdominal aorta. | Creation of time attenuation curves (TAC) in abdominal aorta. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement times measured in seconds in abdominal aorta. | Creation of time attenuation curves (TAC) in abdominal aorta. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement values measured in Hounsfield units(HU) in celiac trunc. | Creation of time attenuation curves (TAC) in celiac trunc. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement times measured in seconds in celiac trunc. | Creation of time attenuation curves (TAC) in celiac trunc. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement values measured in Hounsfield units(HU) in superior mesenteric artery (SMA). | Creation of time attenuation curves (TAC) in SMA. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement times measured in seconds in superior mesenteric artery (SMA). | Creation of time attenuation curves (TAC) in SMA. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement values measured in Hounsfield units(HU) in hepatic artery. | Creation of time attenuation curves (TAC) in hepatic artery. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement times measured in seconds in hepatic artery. | Creation of time attenuation curves (TAC) in hepatic artery. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement values measured in Hounsfield units(HU) in portal vein. | Creation of time attenuation curves (TAC) in portal vein. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement times measured in seconds in portal vein. | Creation of time attenuation curves (TAC) in portal vein. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement values measured in Hounsfield units(HU) in pancreas parenchyma. | Creation of time attenuation curves (TAC) in pancreas parenchyma. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement values measured in Hounsfield units(HU) in pancreatic lesions. | Creation of time attenuation curves (TAC) in pancreatic lesions. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement times measured in seconds in pancreas parenchyma. | Creation of time attenuation curves (TAC) in pancreas parenchyma. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement times measured in seconds in pancreatic lesions. | Creation of time attenuation curves (TAC) in pancreatic lesions. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement values measured in Hounsfield units(HU) in liver parenchyma. | Creation of time attenuation curves (TAC) in liver parenchyma. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement values measured in Hounsfield units(HU) in hepatic lesions. | Creation of time attenuation curves (TAC) in hepatic lesions. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement times measured in seconds in liver parenchyma. | Creation of time attenuation curves (TAC) in liver parenchyma. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| Peak enhancement times measured in seconds in hepatic lesions. | Creation of time attenuation curves (TAC) in hepatic lesions. | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| highest enhancement difference between a hepatic lesion and background liver parenchyma | To measure the highest enhancement difference in Hounsfield units(HU) between a hepatic lesion and background liver parenchyma | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| time-point of highest enhancement difference between a hepatic lesion and background liver parenchyma | To depict the time-point of the highest enhancement difference between a hepatic lesion and background liver parenchyma by comparing their tissue attenuation curves | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| highest enhancement difference between a pancreatic lesion and background pancreatic parenchyma | To measure the highest enhancement difference in Hounsfield units(HU) between a pancreatic lesion and background pancreas parenchyma | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 
| time-point of highest enhancement difference between a pancreatic lesion and background pancreatic parenchyma | To depict the time-point of the highest enhancement difference between a pancreatic lesion and background pancreas parenchyma by comparing their tissue attenuation curves | at the time of intervention (= Multi-phasic CT scan of the abdomen) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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computed tomography, CT angiography, hepatic imaging, pancreatic imaging, hepatocellular cancer, pancreatic adenocarcinoma, liver, pancreas