Koji Takahashi1,2, Daisuke Sasaki3, Mina Yamashita4, Tomoki Sakaue5,4, Daijiro Enomoto4, Hiroe Morioka4, Shigeki Uemura4, Takafumi Okura4, Shuntaro Ikeda5,4, Taizo Kono3, Yoshiyasu Hiratsuka3, Akira Saijo6, Nobuhisa Yamamura6, Sohei Kitazawa7, Taro Yamashita8, Mitsuharu Ueda8. 1. Department of Community Emergency Medicine, Ehime University Graduate School of Medicine, Ehime, Japan. michitokitatsumasa@gmail.com. 2. Department of Cardiology, Yawatahama City General Hospital, 1-638, Ohira, Yawatahama, Ehime, 796-8502, Japan. michitokitatsumasa@gmail.com. 3. Department of Radiology, Yawatahama City General Hospital, Ehime, Japan. 4. Department of Cardiology, Yawatahama City General Hospital, 1-638, Ohira, Yawatahama, Ehime, 796-8502, Japan. 5. Department of Community Emergency Medicine, Ehime University Graduate School of Medicine, Ehime, Japan. 6. Department of Clinical Pathology, Yawatahama City General Hospital, Ehime, Japan. 7. Department of Molecular Pathology, Ehime University Graduate School of Medicine, Ehime, Japan. 8. Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
Abstract
BACKGROUND: Radionuclide imaging using bone-avid tracers plays a critical role in diagnosing transthyretin cardiac amyloidosis (ATTR-CA), but technetium-99m-pyrophosphate (PYP) rarely allows the detection of extracardiac amyloid infiltration. We retrospectively investigated the frequency of PYP uptake in the subcutaneous abdominal fat of patients with ATTR-CA and its relevance to the results of fine-needle aspiration biopsy (FNAB) of this tissue. METHODS: Chest-centered images of PYP scintigraphy were obtained 2 h after the intravenous injection of the tracer (20 mCi), and the frequency of PYP uptake in the subcutaneous abdominal fat was evaluated. Amyloid deposits of fat smears taken by subcutaneous abdominal fat FNAB were assessed by Congo red staining. RESULTS: Twenty-four patients with ATTR-CA were included. Ten (41.7%) patients showed some PYP uptake in the subcutaneous abdominal fat (positive PYP group), and 14 patients did not (negative PYP group). Amyloid deposits were detected by subcutaneous abdominal fat FNAB in 7/10 patients (70.0%) of the positive PYP group versus 0/14 patients (0%) of the negative PYP group, and the difference was significant. CONCLUSIONS: In patients with ATTR-CA, abnormal PYP uptake in the subcutaneous abdominal fat could reflect the regional amyloid deposition confirmed by FNAB of this tissue.
BACKGROUND: Radionuclide imaging using bone-avid tracers plays a critical role in diagnosing transthyretin cardiac amyloidosis (ATTR-CA), but technetium-99m-pyrophosphate (PYP) rarely allows the detection of extracardiac amyloid infiltration. We retrospectively investigated the frequency of PYP uptake in the subcutaneous abdominal fat of patients with ATTR-CA and its relevance to the results of fine-needle aspiration biopsy (FNAB) of this tissue. METHODS: Chest-centered images of PYP scintigraphy were obtained 2 h after the intravenous injection of the tracer (20 mCi), and the frequency of PYP uptake in the subcutaneous abdominal fat was evaluated. Amyloid deposits of fat smears taken by subcutaneous abdominal fat FNAB were assessed by Congo red staining. RESULTS: Twenty-four patients with ATTR-CA were included. Ten (41.7%) patients showed some PYP uptake in the subcutaneous abdominal fat (positive PYP group), and 14 patients did not (negative PYP group). Amyloid deposits were detected by subcutaneous abdominal fat FNAB in 7/10 patients (70.0%) of the positive PYP group versus 0/14 patients (0%) of the negative PYP group, and the difference was significant. CONCLUSIONS: In patients with ATTR-CA, abnormal PYP uptake in the subcutaneous abdominal fat could reflect the regional amyloid deposition confirmed by FNAB of this tissue.