- Email: [email protected]
Re: Role of diffusion-weighted MRI in differentiation of hepatic abscesses from non-infected fluid collections
Clinical Radiology xxx (2014) e1ee1
Contents lists available at ScienceDirect
Clinical Radiology journal homepage: www.clinicalradiologyonline.net
Correspondence
Re: Role of diffusion-weighted MRI in differentiation of hepatic abscesses from non-infected fluid collections Sir d We read the recent article by Schmid-Tannwald et al.,1 published in the Journal with a great interest. In this article, the authors discussed the role of quantitative and qualitative assessment of diffusion-weighted (DW) images and apparent diffusion coefficient (ADC) maps in infected and non-infected collections in the liver. As we have a special interest in DW imaging in the characterization of liver lesions,2e6 we would like to contribute regarding the efficacy of DW imaging and ADC measurement in the evaluation of the hepatic abscess and noninfected fluid collection. As the authors mentioned in the article, ADC values of each lesion were measured by drawing a circular region of interest (ROI), encompassing the entire lesion, on the image in which the lesion was largest. We think that ADC measurement must be performed several times with using small ROIs in different regions and the lowest ADC value must be take into consideration.2e6 In our clinical practice, we noticed that ROIs encompassing the entire lesion can lead to misinterpretation of the ADC value of the lesion, particularly in those with different components such as necrotic, cystic, infected, or neoplastic tissue. Those areas with high ADC values can increase the mean ADC value of the lesion and can lead to misinterpretation. Another issue is the visual assessment of the DW images and ADC maps, which provides easy and confident evaluation of the solidecystic and simpleecomplicated focal liver lesions. Particularly, in hepatic abscess, central diffusion restriction and peripherally relative increased diffusion in DW images and ADC maps are unique findings and these
features can be easily evaluated by visual assessment without time-consuming ADC measurements. Visual assessment is also useful for overcoming the reproducibility problems associated with DW imaging in the liver due different magnetic resonance imaging (MRI) machines, sequence parameters, and differences in ADC values in different parts of the liver.2,4e6
References 1. Schmid-Tannwald C, Schmid-Tannwald CM, Morelli JN, et al. Role of diffusion-weighted MRI in differentiation of hepatic abscesses from noninfected fluid collections. Clin Radiol; 2014; Mar 10. http://dx.doi.org/ 10.1016/j.crad.2014.01.028. pii: S0009-9260(14)00068-3 [Epub ahead of print]. 2. Battal B, Kocaoglu M, Akgun V, et al. Diffusion-weighted imaging in the characterization of focal liver lesions: efficacy of visual assessment. J Comput Assist Tomogr 2011;35:326e31. 3. Battal B, Kocaoglu M, Atay AA, et al. Multifocal peliosis hepatis: MR and diffusion-weighted MR-imaging findings of an atypical case. Ups J Med Sci 2010;115:153e6. € n V, Kocaog lu M. Diffusion-weighted MRI beyond the 4. Battal B, Akgu central nervous system in children. Diagn Interv Radiol 2012;18:288e97. 5. Battal B, Hamcan S, Sari S, et al. Efficacy of diffusion-weighted imaging and apparent diffusion coefficient measurement in the determination of the focal liver lesions. J Med Imaging Radiat Oncol 2013;57:686. 6. Battal B, Akgun V, Kocaoglu M, et al. Diffusion-weighted MR imaging of focal liver lesions in the left and right lobes: would visual assessment and/or normalization of ADC be useful for overcoming their differences in ADC values resulting from its locations? Acad Radiol 2013;20:1472.
V. Akgun*, S. Sari, B. Battal, B. Karaman, M. Kocaoglu Gulhane Military Medical School, Ankara, Turkey E-mail address: [email protected] (V. Akgun)
* Guarantor and correspondent: V. Akgun, Gulhane Military Medical School, Department of Radiology, 06018 Etlik, Ankara, Turkey. Tel.: þ90 530 5525151; fax: þ90 312 3044700. 0009-9260/$ e see front matter Ó 2014 Published by Elsevier Ltd on behalf of The Royal College of Radiologists. http://dx.doi.org/10.1016/j.crad.2014.04.019
Please cite this article in press as: Akgun V, et al., Re: Role of diffusion-weighted MRI in differentiation of hepatic abscesses from non-infected fluid collections, Clinical Radiology (2014), http://dx.doi.org/10.1016/j.crad.2014.04.019
Contents lists available at ScienceDirect
Clinical Radiology journal homepage: www.clinicalradiologyonline.net
Correspondence
Re: Role of diffusion-weighted MRI in differentiation of hepatic abscesses from non-infected fluid collections Sir d We read the recent article by Schmid-Tannwald et al.,1 published in the Journal with a great interest. In this article, the authors discussed the role of quantitative and qualitative assessment of diffusion-weighted (DW) images and apparent diffusion coefficient (ADC) maps in infected and non-infected collections in the liver. As we have a special interest in DW imaging in the characterization of liver lesions,2e6 we would like to contribute regarding the efficacy of DW imaging and ADC measurement in the evaluation of the hepatic abscess and noninfected fluid collection. As the authors mentioned in the article, ADC values of each lesion were measured by drawing a circular region of interest (ROI), encompassing the entire lesion, on the image in which the lesion was largest. We think that ADC measurement must be performed several times with using small ROIs in different regions and the lowest ADC value must be take into consideration.2e6 In our clinical practice, we noticed that ROIs encompassing the entire lesion can lead to misinterpretation of the ADC value of the lesion, particularly in those with different components such as necrotic, cystic, infected, or neoplastic tissue. Those areas with high ADC values can increase the mean ADC value of the lesion and can lead to misinterpretation. Another issue is the visual assessment of the DW images and ADC maps, which provides easy and confident evaluation of the solidecystic and simpleecomplicated focal liver lesions. Particularly, in hepatic abscess, central diffusion restriction and peripherally relative increased diffusion in DW images and ADC maps are unique findings and these
features can be easily evaluated by visual assessment without time-consuming ADC measurements. Visual assessment is also useful for overcoming the reproducibility problems associated with DW imaging in the liver due different magnetic resonance imaging (MRI) machines, sequence parameters, and differences in ADC values in different parts of the liver.2,4e6
References 1. Schmid-Tannwald C, Schmid-Tannwald CM, Morelli JN, et al. Role of diffusion-weighted MRI in differentiation of hepatic abscesses from noninfected fluid collections. Clin Radiol; 2014; Mar 10. http://dx.doi.org/ 10.1016/j.crad.2014.01.028. pii: S0009-9260(14)00068-3 [Epub ahead of print]. 2. Battal B, Kocaoglu M, Akgun V, et al. Diffusion-weighted imaging in the characterization of focal liver lesions: efficacy of visual assessment. J Comput Assist Tomogr 2011;35:326e31. 3. Battal B, Kocaoglu M, Atay AA, et al. Multifocal peliosis hepatis: MR and diffusion-weighted MR-imaging findings of an atypical case. Ups J Med Sci 2010;115:153e6. € n V, Kocaog lu M. Diffusion-weighted MRI beyond the 4. Battal B, Akgu central nervous system in children. Diagn Interv Radiol 2012;18:288e97. 5. Battal B, Hamcan S, Sari S, et al. Efficacy of diffusion-weighted imaging and apparent diffusion coefficient measurement in the determination of the focal liver lesions. J Med Imaging Radiat Oncol 2013;57:686. 6. Battal B, Akgun V, Kocaoglu M, et al. Diffusion-weighted MR imaging of focal liver lesions in the left and right lobes: would visual assessment and/or normalization of ADC be useful for overcoming their differences in ADC values resulting from its locations? Acad Radiol 2013;20:1472.
V. Akgun*, S. Sari, B. Battal, B. Karaman, M. Kocaoglu Gulhane Military Medical School, Ankara, Turkey E-mail address: [email protected] (V. Akgun)
* Guarantor and correspondent: V. Akgun, Gulhane Military Medical School, Department of Radiology, 06018 Etlik, Ankara, Turkey. Tel.: þ90 530 5525151; fax: þ90 312 3044700. 0009-9260/$ e see front matter Ó 2014 Published by Elsevier Ltd on behalf of The Royal College of Radiologists. http://dx.doi.org/10.1016/j.crad.2014.04.019
Please cite this article in press as: Akgun V, et al., Re: Role of diffusion-weighted MRI in differentiation of hepatic abscesses from non-infected fluid collections, Clinical Radiology (2014), http://dx.doi.org/10.1016/j.crad.2014.04.019