Confronto degli agenti di contrasto nella RM epatica per la rilevazione delle metastasi epatiche

The subjects will be randomized into two groups. Both groups will undergo two complete protocol liver magnetic resonance imaging (MRI) for known or suspected colorectal cancer (CRC) metastasis, one exam with gadoxetate disodium and the other exam with gadobenate dimeglumine, within an interval of 3-20 days, but in opposite order, determined randomly.

Gadoxetate disodium MR contrast is now mainly used for the purpose of HBP liver MR imaging to save MR scanner time and total examination time.

• Primovista
• Eovist

The most commonly used MR contrast agent in abdominal imaging is gadobenate dimeglumine, which has mainly the characteristics of an extracellular agent used for most indications of MR examinations.

• MultiHance

The subjects will be randomized into two groups. Both groups will undergo two complete protocol liver MRI for known or suspected CRC metastasis, one exam with gadoxetate disodium and the other exam with gadobenate dimeglumine, within an interval of 3-20 days, but in opposite order, determined randomly.

Gadoxetate disodium MR contrast is now mainly used for the purpose of HBP liver MR imaging to save MR scanner time and total examination time.

• Primovista
• Eovist

The most commonly used MR contrast agent in abdominal imaging is gadobenate dimeglumine, which has mainly the characteristics of an extracellular agent used for most indications of MR examinations.

• MultiHance

The quality of amHBP and aeHBP images was assessed using ordinal response mixed effect models that included right/left image position as a covariate. For each paired comparison, radiologists indicated their preferred hepatobiliary phase image.

Measures of timing used to obtain hepatobiliary phase images.

A single reader analyzed paired Eovist and MultiHance hepatobiliary phase images (N=10 paired datasets). Quantitative metrics included liver-to-metastasis, liver-to-spleen, liver-to-muscle, and liver-to-blood contrast ratios (CNR's), as well as liver signal-to-noise ratio (SNR). All CNR's were calculated as signal intensity of liver relative to the reference tissue, with liver SNR liver signal/liver noise. Higher contrast ratios and higher SNR values indicate greater liver enhancement and improved lesion conspicuity.

A single reader performed a qualitative assessment of Dynamic and Hepatobiliary Phase Image Quality (Likert scale 1-5) for both Eovist and MultiHance Hepatobiliary Phase images (N=10 paired data). Higher scores indicate better image quality.

The primary performance diagnostic will be sensitivity, similar to the recently published retrospective study by Canellas et al. (2019). In addition to other diagnostic performance metrics of interest (e.g., specificity, AUROC), lesions will be analyzed descriptively in terms of number of metastases detected and lesion size.

The primary analysis will use pathology as the gold standard, if available, but will revert to long term imaging in the absence of pathology. To address the potential impact of this limitation, we will also conduct an exploratory analysis to compare the sensitivity and specificity of the imaging methods by each gold standard.

We will also conduct an exploratory analysis to test the validity of long term imaging as a gold standard against available pathology reports.

In addition to analyses for the primary aims, additional analyses will be conducted to examine patient time associated with each imaging method; time metrics can be compared between imaging methods in absolute terms, but also proportionally to sensitivity.

In addition to analyses for the primary aims, additional analyses will be conducted to examine cost associated with each imaging method; cost metrics can be compared between imaging methods in absolute terms, but also proportionally to sensitivity.