- Email: [email protected]
MRI
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Correspondence
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MRI A New Paradigm in Imaging Evaluation of Allergic Bronchopulmonary Aspergillosis? To the Editor:
High-resolution CT (HRCT) scanning is the imaging modality of choice for evaluation of allergic bronchopulmonary aspergillosis (ABPA).1 Besides diagnosis, it has a prognostic significance. High-attenuation mucus (HAM), as defined by the visual appearance of impacted mucus within the bronchi greater than that of paraspinal muscles on CT scan, has been shown to predict relapses as well as correlate with baseline immunologic severity.2 The proposed mechanism for HAM is a variable combination of desiccated mucus and salts of calcium, manganese, and iron.3 Patients with ABPA undergo HRCT scanning at regular intervals. There is a concern regarding the potential effect of cumulative radiation leading to malignancy. This risk is particularly valid in high-risk populations (pregnant patients and children). MRI lacks exposure to ionizing radiations and has become the preferred imaging modality for several chronic diseases at areas previously thought to be difficult to image (eg, bowel imaging in Crohn’s disease and ulcerative colitis).4 There is a scarcity of data regarding the application of MRI in ABPA. We performed MRI in a young woman with ABPA. She underwent HRCT scanning that showed extensive bronchiectasis and HAM. MRI was performed on the same day on a 1.5-Tesla scanner (Magnetom Aera; Siemens AG). The following sequences were performed: axial and coronal T2 turbo spin echo-BLADE (repetition time [TR]/echo time [TE], 120/4,500), axial T1 gradient recalled echo (volumetric interpolated breath-hold examination; TE/TR, 2/4.5), and axial and coronal balanced steady-state-free precession (TR/TE, 1.5/580). The former is a breath-hold sequence and requires five to six breath-holds of about 17 to 23 s. The latter two are free breathing sequences. The entire protocol was completed in 10 min. All of the sequences yielded images of diagnostic quality. MRI findings included hyperintense lesions in lungs (on all sequences, corresponding to the bronchiectasis with impacted mucus) (Figs 1B, 1C), nodules, and hypointense foci (on T2 turbo spin e58 Correspondence
Figure 1 – A-C, CT image (A) shows extensive bilateral bronchiectasis (arrows) with areas of high-attenuation mucus (short arrows). Axial T2-weighted (B) and T1-weighted MRI (C) images show hyperintense areas (short arrows) with hypointense foci seen within some of these areas (arrows).
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echo-BLADE and T1 gradient recalled echo) (Figs 1B, 1C) within some of the hyperintense lesions. The latter finding is of significance as it corresponds to areas of HAM on CT scan (Fig 1A). As HAM represents desiccated mucus and metal salts, it is expected to be hypointense.3 Franzen et al5 reported the comparison of HRCT scanning and MRI findings in five patients with ABPA. The authors found that the resolution of MRI was inadequate to delineate the structural changes in ABPA. However, this study was conducted more than a decade ago. Recently, there have been significant technical developments in MRI technique, including rapid sequences. We believe that MRI will be used more frequently in ABPA at least in the high-risk group in the near future. Mandeep Kumar Garg, MD Pankaj Gupta, MD Ritesh Agarwal, MD, DM, FCCP Kushaljit Singh Sodhi, MD Niranjan Khandelwal, MD Chandigarh, India AFFILIATIONS: From the Department of Radiodiagnosis and Imaging (Drs Garg, Gupta, Sodhi, and Khandelwal) and Department of
journal.publications.chestnet.org
Pulmonary Medicine (Dr Agarwal), Postgraduate Institute of Medical Education & Research (PGIMER). FINANCIAL/NONFINANCIAL DISCLOSURES: The authors have reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article. CORRESPONDENCE TO: Mandeep Kumar Garg, MD, Department of Radiodiagnosis and Imaging, Postgraduate Institute of Medical Education & Research (PGIMER), Chandigarh, India 160012; e-mail: [email protected] © 2015 AMERICAN COLLEGE OF CHEST PHYSICIANS. Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details. DOI: 10.1378/chest.14-2347
References 1. Agarwal R. Allergic bronchopulmonary aspergillosis. Chest. 2009; 135(3):805-826. 2. Agarwal R, Gupta D, Aggarwal AN, Saxena AK, Chakrabarti A, Jindal SK. Clinical significance of hyperattenuating mucoid impaction in allergic bronchopulmonary aspergillosis: an analysis of 155 patients. Chest. 2007;132(4):1183-1190. 3. Dillon WP, Som PM, Fullerton GD. Hypointense MR signal in chronically inspissated sinonasal secretions. Radiology. 1990;174(1): 73-78. 4. Fidler JL, Guimaraes L, Einstein DM. MR imaging of the small bowel. Radiographics. 2009;29(6):1811-1825. 5. Franzen D, Boldt A, Sennekamp HJ. A comparison of high resolution computerized tomography and magnetic resonance imaging in the evaluation of allergic bronchopulmonary aspergillosis [in German]. Pneumologie. 2003;57(11):648-654.
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Correspondence
]
MRI A New Paradigm in Imaging Evaluation of Allergic Bronchopulmonary Aspergillosis? To the Editor:
High-resolution CT (HRCT) scanning is the imaging modality of choice for evaluation of allergic bronchopulmonary aspergillosis (ABPA).1 Besides diagnosis, it has a prognostic significance. High-attenuation mucus (HAM), as defined by the visual appearance of impacted mucus within the bronchi greater than that of paraspinal muscles on CT scan, has been shown to predict relapses as well as correlate with baseline immunologic severity.2 The proposed mechanism for HAM is a variable combination of desiccated mucus and salts of calcium, manganese, and iron.3 Patients with ABPA undergo HRCT scanning at regular intervals. There is a concern regarding the potential effect of cumulative radiation leading to malignancy. This risk is particularly valid in high-risk populations (pregnant patients and children). MRI lacks exposure to ionizing radiations and has become the preferred imaging modality for several chronic diseases at areas previously thought to be difficult to image (eg, bowel imaging in Crohn’s disease and ulcerative colitis).4 There is a scarcity of data regarding the application of MRI in ABPA. We performed MRI in a young woman with ABPA. She underwent HRCT scanning that showed extensive bronchiectasis and HAM. MRI was performed on the same day on a 1.5-Tesla scanner (Magnetom Aera; Siemens AG). The following sequences were performed: axial and coronal T2 turbo spin echo-BLADE (repetition time [TR]/echo time [TE], 120/4,500), axial T1 gradient recalled echo (volumetric interpolated breath-hold examination; TE/TR, 2/4.5), and axial and coronal balanced steady-state-free precession (TR/TE, 1.5/580). The former is a breath-hold sequence and requires five to six breath-holds of about 17 to 23 s. The latter two are free breathing sequences. The entire protocol was completed in 10 min. All of the sequences yielded images of diagnostic quality. MRI findings included hyperintense lesions in lungs (on all sequences, corresponding to the bronchiectasis with impacted mucus) (Figs 1B, 1C), nodules, and hypointense foci (on T2 turbo spin e58 Correspondence
Figure 1 – A-C, CT image (A) shows extensive bilateral bronchiectasis (arrows) with areas of high-attenuation mucus (short arrows). Axial T2-weighted (B) and T1-weighted MRI (C) images show hyperintense areas (short arrows) with hypointense foci seen within some of these areas (arrows).
[
147#2 CHEST FEBRUARY 2015
]
echo-BLADE and T1 gradient recalled echo) (Figs 1B, 1C) within some of the hyperintense lesions. The latter finding is of significance as it corresponds to areas of HAM on CT scan (Fig 1A). As HAM represents desiccated mucus and metal salts, it is expected to be hypointense.3 Franzen et al5 reported the comparison of HRCT scanning and MRI findings in five patients with ABPA. The authors found that the resolution of MRI was inadequate to delineate the structural changes in ABPA. However, this study was conducted more than a decade ago. Recently, there have been significant technical developments in MRI technique, including rapid sequences. We believe that MRI will be used more frequently in ABPA at least in the high-risk group in the near future. Mandeep Kumar Garg, MD Pankaj Gupta, MD Ritesh Agarwal, MD, DM, FCCP Kushaljit Singh Sodhi, MD Niranjan Khandelwal, MD Chandigarh, India AFFILIATIONS: From the Department of Radiodiagnosis and Imaging (Drs Garg, Gupta, Sodhi, and Khandelwal) and Department of
journal.publications.chestnet.org
Pulmonary Medicine (Dr Agarwal), Postgraduate Institute of Medical Education & Research (PGIMER). FINANCIAL/NONFINANCIAL DISCLOSURES: The authors have reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article. CORRESPONDENCE TO: Mandeep Kumar Garg, MD, Department of Radiodiagnosis and Imaging, Postgraduate Institute of Medical Education & Research (PGIMER), Chandigarh, India 160012; e-mail: [email protected] © 2015 AMERICAN COLLEGE OF CHEST PHYSICIANS. Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details. DOI: 10.1378/chest.14-2347
References 1. Agarwal R. Allergic bronchopulmonary aspergillosis. Chest. 2009; 135(3):805-826. 2. Agarwal R, Gupta D, Aggarwal AN, Saxena AK, Chakrabarti A, Jindal SK. Clinical significance of hyperattenuating mucoid impaction in allergic bronchopulmonary aspergillosis: an analysis of 155 patients. Chest. 2007;132(4):1183-1190. 3. Dillon WP, Som PM, Fullerton GD. Hypointense MR signal in chronically inspissated sinonasal secretions. Radiology. 1990;174(1): 73-78. 4. Fidler JL, Guimaraes L, Einstein DM. MR imaging of the small bowel. Radiographics. 2009;29(6):1811-1825. 5. Franzen D, Boldt A, Sennekamp HJ. A comparison of high resolution computerized tomography and magnetic resonance imaging in the evaluation of allergic bronchopulmonary aspergillosis [in German]. Pneumologie. 2003;57(11):648-654.
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