MRI is also not explicitly recommended in the available practice guidelines for the evaluation of chronic cough by the ACCP [1]. Limitations of pulmonary MRI include low signal-to-noise ratio (especially with normally aerated lung), low spatial resolution, and need for adequate breath-hold technique or respiratory gating [46]. Based on our literature review, there is limited evidence evaluating the diagnostic quality of MRI for the evaluation of pulmonary abnormalities. Ohno et al [47] analyzed 85 consecutive patients with a high prevalence of pulmonary abnormality with high-resolution pulmonary MR using ultrashort time to echo and compared findings with both standard and LDCT acquisition. High-resolution MRI demonstrated excellent correlation with standard dose CT for mass or nodule, GGO, and lymphadenopathy. MRI demonstrated 89% sensitivity and 99% specificity for mass or nodule identification. The authors noted diminished imaging quality; however, this did not affect overall evaluation. The role of MRI in the setting of chronic cough and increased cancer risk remains unknown at this time. Future research in this setting may be warranted for certain populations. CT Chest The most commonly identified etiologies reported for chronic cough are asthma, GERD, and UACS [1]. Prospective case series have shown clinical efficacy in diagnosing and managing chronic cough using standard clinical algorithms with minimal investigation [7,17]. When this has failed to result in diagnosis, or when empiric sequential treatment for the most common etiologies has failed to resolve symptoms, further investigative modalities and additional specialty referrals have been recommended. The ACCP and German Respiratory Society both recommend HRCT after an appropriate clinical evaluation and empiric trial has been performed [1,29]. HRCT is typically performed with multidetector helical CT, and the standard for performance can be reviewed in the ACR practice parameter for HRCT [54].
Chronic Cough. MRI is also not explicitly recommended in the available practice guidelines for the evaluation of chronic cough by the ACCP [1]. Limitations of pulmonary MRI include low signal-to-noise ratio (especially with normally aerated lung), low spatial resolution, and need for adequate breath-hold technique or respiratory gating [46]. Based on our literature review, there is limited evidence evaluating the diagnostic quality of MRI for the evaluation of pulmonary abnormalities. Ohno et al [47] analyzed 85 consecutive patients with a high prevalence of pulmonary abnormality with high-resolution pulmonary MR using ultrashort time to echo and compared findings with both standard and LDCT acquisition. High-resolution MRI demonstrated excellent correlation with standard dose CT for mass or nodule, GGO, and lymphadenopathy. MRI demonstrated 89% sensitivity and 99% specificity for mass or nodule identification. The authors noted diminished imaging quality; however, this did not affect overall evaluation. The role of MRI in the setting of chronic cough and increased cancer risk remains unknown at this time. Future research in this setting may be warranted for certain populations. CT Chest The most commonly identified etiologies reported for chronic cough are asthma, GERD, and UACS [1]. Prospective case series have shown clinical efficacy in diagnosing and managing chronic cough using standard clinical algorithms with minimal investigation [7,17]. When this has failed to result in diagnosis, or when empiric sequential treatment for the most common etiologies has failed to resolve symptoms, further investigative modalities and additional specialty referrals have been recommended. The ACCP and German Respiratory Society both recommend HRCT after an appropriate clinical evaluation and empiric trial has been performed [1,29]. HRCT is typically performed with multidetector helical CT, and the standard for performance can be reviewed in the ACR practice parameter for HRCT [54].