Relevance of b-values in evaluating liver fibrosis

A study in healthy and cirrhotic subjects using two single-shot spin-echo echo-planar diffusion-weighted sequences

Rossano Girometti, Alessandro Furlan, Gennaro Esposito, Massimo Bazzocchi, Giuseppe Como, Franca Soldano, Miriam Isola, Pierluigi Toniutto, Chiara Zuiani

    Research output: Contribution to journalArticle

    Abstract

    Purpose: To investigate the relevance of increasing b-values in evaluating liver fibrosis through the agreement of two diffusion-weighted (DW) sequences. Materials and Methods: A total of 29 cirrhotic patients and 29 healthy volunteers were studied on a 1.5T system. Two single-shot spin-echo echo-planar sequences were acquired using sets of increasing b-values: 0, 150, 250, and 400 seconds/mm2 (first sequence: DW1a) and 0, 150, 250, 400, 600, and 800 seconds/mm2 (second sequence: DW2a). Apparent diffusion coefficients (ADCs) of the hepatic parenchyma were calculated on ADC maps. Noise-scaled single-point ADCs were calculated for each sequence from b = 400 seconds/mm 2. Results: ADCs resulted significantly lower in cirrhotic patients compared to controls using both DW1 a (mean 1.14 ± 0.20 x 10 -3mm2/second vs. 1.54 ± 0.12 x 10 -3mm2/second; P < 0.0001) and DW2a (mean 0.91 ± 0.18 × 1-3mm2/second vs. 1.04 ± 0.18 × 10-3mm2/second; P = 0.0089). DW1 and DW2, respectively significantly differed in diagnostic performance at receiver operating characteristic (ROC) curve analysis (P = 0.003), showing AUCs of 0.93 (sensitivity 89.7%, specificity 100%) and 0.73 (sensitivity 62.1%, specificity 79.3%), respectively. Noise-scaled single-point ADCs showed a progressive convergence to similar values in cirrhotic and healthy livers at b = 800 seconds/mm2 (1.12 ±0.27 × 10-3mm 2/second vs. 1.13 ± 0.17 × 10 3mm 2/second). Conclusion: A DW sequence is accurate in assessing liver fibrosis using intermediate (400 seconds/mm2) rather than high (800 seconds/mm2) maximum b-values, but after proper recalculation of ADCs the effects of perfusion rather than diffusion should be considered responsible for the higher accuracy at lower b-values.

    Original languageEnglish (US)
    Pages (from-to)411-419
    Number of pages9
    JournalJournal of Magnetic Resonance Imaging
    Volume28
    Issue number2
    DOIs
    StatePublished - Aug 1 2008

    Fingerprint

    Liver Cirrhosis
    Healthy Volunteers
    Noise
    Sensitivity and Specificity
    Liver
    ROC Curve
    Area Under Curve
    Perfusion

    Keywords

    • b-values
    • Diffusion-weighted MRI
    • Liver cirrhosis
    • Liver diseases
    • Liver fibrosis

    ASJC Scopus subject areas

    • Radiology Nuclear Medicine and imaging

    Cite this

    Relevance of b-values in evaluating liver fibrosis : A study in healthy and cirrhotic subjects using two single-shot spin-echo echo-planar diffusion-weighted sequences. / Girometti, Rossano; Furlan, Alessandro; Esposito, Gennaro; Bazzocchi, Massimo; Como, Giuseppe; Soldano, Franca; Isola, Miriam; Toniutto, Pierluigi; Zuiani, Chiara.

    In: Journal of Magnetic Resonance Imaging, Vol. 28, No. 2, 01.08.2008, p. 411-419.

    Research output: Contribution to journalArticle

    Girometti, Rossano ; Furlan, Alessandro ; Esposito, Gennaro ; Bazzocchi, Massimo ; Como, Giuseppe ; Soldano, Franca ; Isola, Miriam ; Toniutto, Pierluigi ; Zuiani, Chiara. / Relevance of b-values in evaluating liver fibrosis : A study in healthy and cirrhotic subjects using two single-shot spin-echo echo-planar diffusion-weighted sequences. In: Journal of Magnetic Resonance Imaging. 2008 ; Vol. 28, No. 2. pp. 411-419.
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    abstract = "Purpose: To investigate the relevance of increasing b-values in evaluating liver fibrosis through the agreement of two diffusion-weighted (DW) sequences. Materials and Methods: A total of 29 cirrhotic patients and 29 healthy volunteers were studied on a 1.5T system. Two single-shot spin-echo echo-planar sequences were acquired using sets of increasing b-values: 0, 150, 250, and 400 seconds/mm2 (first sequence: DW1a) and 0, 150, 250, 400, 600, and 800 seconds/mm2 (second sequence: DW2a). Apparent diffusion coefficients (ADCs) of the hepatic parenchyma were calculated on ADC maps. Noise-scaled single-point ADCs were calculated for each sequence from b = 400 seconds/mm 2. Results: ADCs resulted significantly lower in cirrhotic patients compared to controls using both DW1 a (mean 1.14 ± 0.20 x 10 -3mm2/second vs. 1.54 ± 0.12 x 10 -3mm2/second; P < 0.0001) and DW2a (mean 0.91 ± 0.18 × 1-3mm2/second vs. 1.04 ± 0.18 × 10-3mm2/second; P = 0.0089). DW1 and DW2, respectively significantly differed in diagnostic performance at receiver operating characteristic (ROC) curve analysis (P = 0.003), showing AUCs of 0.93 (sensitivity 89.7{\%}, specificity 100{\%}) and 0.73 (sensitivity 62.1{\%}, specificity 79.3{\%}), respectively. Noise-scaled single-point ADCs showed a progressive convergence to similar values in cirrhotic and healthy livers at b = 800 seconds/mm2 (1.12 ±0.27 × 10-3mm 2/second vs. 1.13 ± 0.17 × 10 3mm 2/second). Conclusion: A DW sequence is accurate in assessing liver fibrosis using intermediate (400 seconds/mm2) rather than high (800 seconds/mm2) maximum b-values, but after proper recalculation of ADCs the effects of perfusion rather than diffusion should be considered responsible for the higher accuracy at lower b-values.",
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    author = "Rossano Girometti and Alessandro Furlan and Gennaro Esposito and Massimo Bazzocchi and Giuseppe Como and Franca Soldano and Miriam Isola and Pierluigi Toniutto and Chiara Zuiani",
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    AU - Girometti, Rossano

    AU - Furlan, Alessandro

    AU - Esposito, Gennaro

    AU - Bazzocchi, Massimo

    AU - Como, Giuseppe

    AU - Soldano, Franca

    AU - Isola, Miriam

    AU - Toniutto, Pierluigi

    AU - Zuiani, Chiara

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    N2 - Purpose: To investigate the relevance of increasing b-values in evaluating liver fibrosis through the agreement of two diffusion-weighted (DW) sequences. Materials and Methods: A total of 29 cirrhotic patients and 29 healthy volunteers were studied on a 1.5T system. Two single-shot spin-echo echo-planar sequences were acquired using sets of increasing b-values: 0, 150, 250, and 400 seconds/mm2 (first sequence: DW1a) and 0, 150, 250, 400, 600, and 800 seconds/mm2 (second sequence: DW2a). Apparent diffusion coefficients (ADCs) of the hepatic parenchyma were calculated on ADC maps. Noise-scaled single-point ADCs were calculated for each sequence from b = 400 seconds/mm 2. Results: ADCs resulted significantly lower in cirrhotic patients compared to controls using both DW1 a (mean 1.14 ± 0.20 x 10 -3mm2/second vs. 1.54 ± 0.12 x 10 -3mm2/second; P < 0.0001) and DW2a (mean 0.91 ± 0.18 × 1-3mm2/second vs. 1.04 ± 0.18 × 10-3mm2/second; P = 0.0089). DW1 and DW2, respectively significantly differed in diagnostic performance at receiver operating characteristic (ROC) curve analysis (P = 0.003), showing AUCs of 0.93 (sensitivity 89.7%, specificity 100%) and 0.73 (sensitivity 62.1%, specificity 79.3%), respectively. Noise-scaled single-point ADCs showed a progressive convergence to similar values in cirrhotic and healthy livers at b = 800 seconds/mm2 (1.12 ±0.27 × 10-3mm 2/second vs. 1.13 ± 0.17 × 10 3mm 2/second). Conclusion: A DW sequence is accurate in assessing liver fibrosis using intermediate (400 seconds/mm2) rather than high (800 seconds/mm2) maximum b-values, but after proper recalculation of ADCs the effects of perfusion rather than diffusion should be considered responsible for the higher accuracy at lower b-values.

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    KW - b-values

    KW - Diffusion-weighted MRI

    KW - Liver cirrhosis

    KW - Liver diseases

    KW - Liver fibrosis

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