Correspondence
Value of 3T 1H-magnetic resonance spectroscopy in the differentiation of benign and malignant breast tumors
Acta Radiologica 2014, Vol. 55(4) 416–417 ! The Foundation Acta Radiologica 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0284185113498238 acr.sagepub.com
Bilal Battal, Veysel Akgun and Bulent Karaman
We read the recent article entitled ‘‘Application value of 3T 1H-magnetic resonance spectroscopy in diagnosing breast tumors’’ by Vassiou et al. (1), published in Acta Radiologica, with great interest. They evaluated the clinical significance of 1Proton (1H)-magnetic resonance spectroscopy (MRS) at 3T in the assessment of benign and malignant breast lesions in combination with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Authors reported that 1H-MRS showed a higher specificity, and lower sensitivity and accuracy values than DCE-MRI. Moreover, the combination of breast imaging reporting and data system (BI-RADS) classification and 1H-MRS provided higher accuracy as well as higher specificity compared to BI-RADS classification. The authors concluded that 1 H-MRS can be used as a useful adjunct during lesion characterization in clinical routine in cases classified as BI-RADS 3 and 4 (1). We would like to contribute regarding value of 3T 1H-MRS in the differentiation of benign and malignant breast tumors. In addition, we need clarification from the authors on a few points so as not to lead to misinterpretation by readers. First, as also emphasized by the authors, the available dynamic morphological and kinetic features used for conventional and DCE-MRI interpretation have high levels of sensitivity. We agree with the authors that 1H-MRS may be a useful technique at 3T due to high signal-to-noise ratio and permit the use of small voxel in differentiation of small breast lesions. In the Methods section, the authors stated that the selected voxel sizes were 1–8 cm3, but the smallest voxel size was indicated as 3.375 cm3 (probably 1.5 1.5 1.5 cm) in Table 2. We are curious why the authors did not select a smaller voxel size (for example, 1 cm3), especially in small lesions (lesion size 1 cm). Since size of lesions was reported to be in the range of 0.8–9 cm by the authors, we know that the authors have some lesions of this size. In small lesions, the use of large voxel size causes contamination of peri-lesional normal breast parenchyma and fat tissue, and leads to false-negative 1H-MRS results.
Second, in the Methods section, the authors stated that BI-RADS 2 lesions were considered benign, and BI-RADS 3, 4, and 5 lesions were considered malignant in the statistical analysis of the BI-RADS classification system. This is so controversial and we do not agree with the authors on this point. The findings in the BIRADS 3 category have a very good chance (>98%) of being benign. BI-RADS recommends short time frame (6 months) follow-up imaging rather than immediate biopsy for category 3 probably benign lesions. We suggest that BI-RADS 3 lesions should be considered as benign lesions similar to recent comprehensive study performed by Pinker-Domenig et al. (2). If BI-RADS 3 lesions were considered benign, the BI-RADS classification system would have 100% sensitivity, 81.8% specificity, and 92.3% accuracy that are higher than 1 H-MRS and similar with combination of DCE-MRI and 1H-MRS results. Third, since the authors did not clearly describe the combination method of the BI-RADS classification and 1 H-MRS results in the manuscript, we did not understand and interpret the sensitivity, specificity, and accuracy values of the combined technique. We tried to calculate and figure out the sensitivity, specificity, and accuracy ratios from the information in the text and tables of the manuscript. However, there are two discrepancies about the number of choline- negative and positive lesions, and AUC value of BI-RADS classification system. Although the authors presented 12 Cho () and 14 Cho (þ) cases in Table 1, there are 13 Cho () and 13 Cho (þ) cases in Table 2. Similarly, the AUC value of BI-RADS classification system was reported to be 0.846 in the Results section. However the same parameter was reported as 0.864 in Fig. 5b. Gulhane Military Medical School, Department of Radiology, Etlik, Ankara, Turkey Corresponding author: Bilal Battal, Gulhane Military Medical School, Department of Radiology, 06018, Etlik, Ankara, Turkey. Email: [email protected]
Downloaded from acr.sagepub.com at FUDAN UNIV LIB on May 8, 2015
Battal et al.
417
We think that the combined evaluation technique of BIRADS and 1H-MRS should be clearly explained, and accuracy values for BI-RADS and combined technique should be checked by the authors for avoiding misunderstandings by the readers. As an example, what are the final diagnoses (benign or malignant) of BI-RADS 2 but Cho (þ) lesions, and BI-RADS 4 but Cho () lesions in the combined evaluation technique? Finally, the authors claimed that 1H-MRS can be used as a useful adjunct during lesion characterization in clinical routine in cases classified as BI-RADS 3 and 4. We believe that despite recent MRI systems with high magnetic field strengths, sophisticated coils, and
fast sequences, adoption of 1H-MRS into clinical routine in the discrimination of the breast lesions is still difficult due to its relatively low accuracy value, difficulty of implementation, and cost-effectiveness. References 1. Vassiou K, Tsougos I, Kousi E, et al. Application value of 3T 1H-magnetic resonance spectroscopy in diagnosing breast tumors. Acta Radiol 2013;54:380–388. 2. Pinker-Domenig K, Bogner W, Gruber S, et al. High resolution MRI of the breast at 3 T: which BI-RADSÕ descriptors are most strongly associated with the diagnosis of breast cancer? Eur Radiol 2012;22:322–330.
Downloaded from acr.sagepub.com at FUDAN UNIV LIB on May 8, 2015
Value of 3T 1H-magnetic resonance spectroscopy in the differentiation of benign and malignant breast tumors
Acta Radiologica 2014, Vol. 55(4) 416–417 ! The Foundation Acta Radiologica 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0284185113498238 acr.sagepub.com
Bilal Battal, Veysel Akgun and Bulent Karaman
We read the recent article entitled ‘‘Application value of 3T 1H-magnetic resonance spectroscopy in diagnosing breast tumors’’ by Vassiou et al. (1), published in Acta Radiologica, with great interest. They evaluated the clinical significance of 1Proton (1H)-magnetic resonance spectroscopy (MRS) at 3T in the assessment of benign and malignant breast lesions in combination with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Authors reported that 1H-MRS showed a higher specificity, and lower sensitivity and accuracy values than DCE-MRI. Moreover, the combination of breast imaging reporting and data system (BI-RADS) classification and 1H-MRS provided higher accuracy as well as higher specificity compared to BI-RADS classification. The authors concluded that 1 H-MRS can be used as a useful adjunct during lesion characterization in clinical routine in cases classified as BI-RADS 3 and 4 (1). We would like to contribute regarding value of 3T 1H-MRS in the differentiation of benign and malignant breast tumors. In addition, we need clarification from the authors on a few points so as not to lead to misinterpretation by readers. First, as also emphasized by the authors, the available dynamic morphological and kinetic features used for conventional and DCE-MRI interpretation have high levels of sensitivity. We agree with the authors that 1H-MRS may be a useful technique at 3T due to high signal-to-noise ratio and permit the use of small voxel in differentiation of small breast lesions. In the Methods section, the authors stated that the selected voxel sizes were 1–8 cm3, but the smallest voxel size was indicated as 3.375 cm3 (probably 1.5 1.5 1.5 cm) in Table 2. We are curious why the authors did not select a smaller voxel size (for example, 1 cm3), especially in small lesions (lesion size 1 cm). Since size of lesions was reported to be in the range of 0.8–9 cm by the authors, we know that the authors have some lesions of this size. In small lesions, the use of large voxel size causes contamination of peri-lesional normal breast parenchyma and fat tissue, and leads to false-negative 1H-MRS results.
Second, in the Methods section, the authors stated that BI-RADS 2 lesions were considered benign, and BI-RADS 3, 4, and 5 lesions were considered malignant in the statistical analysis of the BI-RADS classification system. This is so controversial and we do not agree with the authors on this point. The findings in the BIRADS 3 category have a very good chance (>98%) of being benign. BI-RADS recommends short time frame (6 months) follow-up imaging rather than immediate biopsy for category 3 probably benign lesions. We suggest that BI-RADS 3 lesions should be considered as benign lesions similar to recent comprehensive study performed by Pinker-Domenig et al. (2). If BI-RADS 3 lesions were considered benign, the BI-RADS classification system would have 100% sensitivity, 81.8% specificity, and 92.3% accuracy that are higher than 1 H-MRS and similar with combination of DCE-MRI and 1H-MRS results. Third, since the authors did not clearly describe the combination method of the BI-RADS classification and 1 H-MRS results in the manuscript, we did not understand and interpret the sensitivity, specificity, and accuracy values of the combined technique. We tried to calculate and figure out the sensitivity, specificity, and accuracy ratios from the information in the text and tables of the manuscript. However, there are two discrepancies about the number of choline- negative and positive lesions, and AUC value of BI-RADS classification system. Although the authors presented 12 Cho () and 14 Cho (þ) cases in Table 1, there are 13 Cho () and 13 Cho (þ) cases in Table 2. Similarly, the AUC value of BI-RADS classification system was reported to be 0.846 in the Results section. However the same parameter was reported as 0.864 in Fig. 5b. Gulhane Military Medical School, Department of Radiology, Etlik, Ankara, Turkey Corresponding author: Bilal Battal, Gulhane Military Medical School, Department of Radiology, 06018, Etlik, Ankara, Turkey. Email: [email protected]
Downloaded from acr.sagepub.com at FUDAN UNIV LIB on May 8, 2015
Battal et al.
417
We think that the combined evaluation technique of BIRADS and 1H-MRS should be clearly explained, and accuracy values for BI-RADS and combined technique should be checked by the authors for avoiding misunderstandings by the readers. As an example, what are the final diagnoses (benign or malignant) of BI-RADS 2 but Cho (þ) lesions, and BI-RADS 4 but Cho () lesions in the combined evaluation technique? Finally, the authors claimed that 1H-MRS can be used as a useful adjunct during lesion characterization in clinical routine in cases classified as BI-RADS 3 and 4. We believe that despite recent MRI systems with high magnetic field strengths, sophisticated coils, and
fast sequences, adoption of 1H-MRS into clinical routine in the discrimination of the breast lesions is still difficult due to its relatively low accuracy value, difficulty of implementation, and cost-effectiveness. References 1. Vassiou K, Tsougos I, Kousi E, et al. Application value of 3T 1H-magnetic resonance spectroscopy in diagnosing breast tumors. Acta Radiol 2013;54:380–388. 2. Pinker-Domenig K, Bogner W, Gruber S, et al. High resolution MRI of the breast at 3 T: which BI-RADSÕ descriptors are most strongly associated with the diagnosis of breast cancer? Eur Radiol 2012;22:322–330.
Downloaded from acr.sagepub.com at FUDAN UNIV LIB on May 8, 2015
