Tomoya Tateishi1, Takeshi Johkoh2, Fumikazu Sakai3, Yasunari Miyazaki4, Takashi Ogura5, Kazuya Ichikado6, Takafumi Suda7, Yoshio Taguchi8, Yoshikazu Inoue9, Tamiko Takemura10, Thomas V Colby11, Hiromitsu Sumikawa12, Kiminori Fujimoto13, Hiroaki Arakawa14, Suhail Raoof15, Naohiko Inase4. 1. Department of Respiratory Medicine, Tokyo Medical and Dental University, 5-45 Yushima 1-chome, Bunkyo-ku, Tokyo, 113-8519, Japan. tateishi.pulm@tmd.ac.jp. 2. Department of Radiology, Kansai Rosai Hospital, Hyogo, Japan. 3. Department of Diagnostic Radiology, Saitama Medical University, Saitama, Japan. 4. Department of Respiratory Medicine, Tokyo Medical and Dental University, 5-45 Yushima 1-chome, Bunkyo-ku, Tokyo, 113-8519, Japan. 5. Department of Respiratory Medicine, Kanagawa Cardiovascular and Respiratory Center, Yokohama, Kanagawa, Japan. 6. Division of Respiratory Medicine, Saiseikai Kumamoto Hospital, Kumamoto, Japan. 7. Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan. 8. Department of Respiratory Medicine, Tenri Hospital, Nara, Japan. 9. Clinical Research Center, National Hospital Organization, Kinki-Chuo Chest Medical Center, Osaka, Japan. 10. Department of Pathology, Kanagawa Cardiovascular and Respiratory Center, Yokohama, Kanagawa, Japan. 11. Department of Laboratory Medicine and Pathology, Mayo Clinic Arizona, Arizona, USA. 12. Department of Radiology, Sakai City Medical Center, Osaka, Japan. 13. Department of Radiology, Kurume University School of Medicine, Fukuoka, Japan. 14. Department of Radiology, Dokkyo Medical University School of Medicine, Tochigi, Japan. 15. Division of Pulmonary Medicine, Lenox Hill Hospital, New York, NY, USA.
Abstract
PURPOSE: Radiologic diagnosis of chronic hypersensitivity pneumonitis (CHP) presenting a usual interstitial pneumonia (UIP) pattern is challenging. The aim of this study was to identify the high-resolution CT (HRCT) findings which are useful to discriminate CHP-UIP from idiopathic pulmonary fibrosis (IPF). MATERIALS AND METHODS: This study included 49 patients with well-established bird-related CHP-UIP, histologically confirmed, and 49 patients with IPF. Two groups of observers independently assessed HRCT, evaluated the extent of each abnormal HRCT finding. When their radiological diagnosis was CHP-UIP, they noted the HRCT findings inconsistent with IPF. RESULTS: Correct CT diagnoses were made in 79% of CHP-UIP and 53% of IPF. Although no apparent difference was seen in the extent of each HRCT finding, upper or mid-lung predominance, extensive ground-glass abnormality, and profuse micronodules were more frequently pointed out as inconsistent findings in CHP-UIP than IPF (p = 0.007, 0.010, 0.001, respectively). On regression analysis, profuse micronodules [OR 13.34 (2.85-62.37); p = 0.001] and upper or mid-lung predominance of findings [OR 2.86 (1.16-7.01); p = 0.022] remained as variables in the equation. CONCLUSION: In this cohort, some IPF cases were misdiagnosed as CHP-UIP. Profuse micronodules and upper or mid-lung predominance are important clues for the differentiation of CHP-UIP from IPF.
PURPOSE: Radiologic diagnosis of chronic hypersensitivity pneumonitis (CHP) presenting a usual interstitial pneumonia (UIP) pattern is challenging. The aim of this study was to identify the high-resolution CT (HRCT) findings which are useful to discriminate CHP-UIP from idiopathic pulmonary fibrosis (IPF). MATERIALS AND METHODS: This study included 49 patients with well-established bird-related CHP-UIP, histologically confirmed, and 49 patients with IPF. Two groups of observers independently assessed HRCT, evaluated the extent of each abnormal HRCT finding. When their radiological diagnosis was CHP-UIP, they noted the HRCT findings inconsistent with IPF. RESULTS: Correct CT diagnoses were made in 79% of CHP-UIP and 53% of IPF. Although no apparent difference was seen in the extent of each HRCT finding, upper or mid-lung predominance, extensive ground-glass abnormality, and profuse micronodules were more frequently pointed out as inconsistent findings in CHP-UIP than IPF (p = 0.007, 0.010, 0.001, respectively). On regression analysis, profuse micronodules [OR 13.34 (2.85-62.37); p = 0.001] and upper or mid-lung predominance of findings [OR 2.86 (1.16-7.01); p = 0.022] remained as variables in the equation. CONCLUSION: In this cohort, some IPF cases were misdiagnosed as CHP-UIP. Profuse micronodules and upper or mid-lung predominance are important clues for the differentiation of CHP-UIP from IPF.