Doppler Evaluation of Intrathyroid Arterial Resistances During Preoperative Treatment with Lugol's Iodide Solution in Patients with Diffuse Toxic Goiter
Abstract
BACKGROUND: The aim of this study was to ascertain the utility of echo-Doppler in the analysis of the low resistance thyroid vascularization in diffuse toxic goiter (DTG), and the effectiveness of Lugol's solution (iodine-iodide solution) in patients undergoing thyroidectomy. STUDY DESIGN: Twenty-five patients with diffuse toxic goiter were evaluated and compared with 19 normal subjects. Patients were treated with increasing doses of Lugol's solution 2% for 7 days until a total dose of 75 mg of iodine was given. Echo-Doppler was performed on the last day of treatment, 12 hours before operation. RESULTS: Mean basal Doppler Resistance Index (RI) of intrathyroid arterial flow was significantly lower in patients with DTG compared with normal controls (0.4718 +/- 0.0625 versus 0.55 +/- 0.05, range: 0.472 to 0.643; p = 0.008). Moreover, the RI was significantly increased in patients with DTG after Lugol's solution (+16.46 +/- 10.22%, range: -2.59 to +39.97; p< 0.0005). CONCLUSIONS: Echo-Doppler RI allowed documenting lower arterial resistances within the thyroid gland in patients with DTG. The use of preoperative Lugol's solution therapy induces normalization of those changes for safer thyroidectomy.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
Preoperative KI, SSKI, or Lugol's solution decreases thyroid blood flow, vascularity, and intraoperative blood loss during thyroidectomy.
“This treatment is beneficial because it decreases thyroid blood flow, vascularity, and intraoperative blood loss during thyroidectomy (181,182).”
From 2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis (2016) · cites this paper as [182]
Cites
Color-flow Doppler sonography in Graves disease: "thyroid inferno"
Ralls, P., Mayekawa, D. S., Lee, K. P., Colletti, P., Radin, D., BOSWELL, W. D., & Halls, J. (1988) · American Journal of Roentgenology · doi:10.2214/ajr.150.4.781 · Cited by 221 · see citing works
Effect of heart rate on Doppler measurements of resistive index in renal arteries.
Mostbeck, G., Gössinger, H., Mallek, R., Siostrzonek, P., Schneider, B., & Tscholakoff, D. (1990) · Radiology · doi:10.1148/radiology.175.2.2183288 · Cited by 164 · see citing works
Sabbà, C., Weltin, G. G., Cicchetti, D. V., Ferraioli, G., Taylor, K. J. W., Nakamura, T., Moriyasu, F., & Groszmann, R. J. (1990) · Gastroenterology · doi:10.1016/0016-5085(90)91097-p · Cited by 154 · see citing works
Solbiati, L., Cioffi, V., & Ballarati, E. (1992) · PubMed · Cited by 138 · see citing works
Ultrasonography related to clinical and laboratory findings in lymphocytic thyroiditis
Gutekunst, R., Hafermann, W., Mansky, T., & Scriba, P. C. (1989) · European Journal of Endocrinology · doi:10.1530/acta.0.1210129 · Cited by 133 · see citing works
Dc, C., Mh, W., Woodcock, J. P., Curley, I., Lazarus, Fung, H., John, R. M., Hall, R., & Am, M. (1987) · PubMed · Cited by 61 · see citing works
Lugol's iodine: Its effect on thyroid blood flow in patients with thyrotoxicosis
Marigold, J. H., Morgan, A., Earle, D. J., Young, A. E., & Croft, D. N. (1985) · British journal of surgery · doi:10.1002/bjs.1800720118 · Cited by 48 · see citing works
Duplex scan‐derived thyroid blood flow in euthyroid and hyperthyroid patients
Hodgson, K. J., Lazarus, J. H., Wheeler, M. H., Woodcock, J. P., Owen, G. M., McGregor, A. M., & Hall, R. (1988) · World Journal of Surgery · doi:10.1007/bf01655423 · Cited by 41 · see citing works
Veglio, F., Frascisco, M. F., Melchio, R., Provera, E., Rabbia, F., Oliva, S., & Chiandussi, L. (1995) · Kidney International · doi:10.1038/ki.1995.455 · Cited by 39 · see citing works
Clinical Application of Doppler Ultrasound
Mondro, S. (1996) · Hepatology · doi:10.1002/hep.510230440 · Cited by 32 · see citing works
Thyroidectomy: is Lugol's iodine necessary?
Coyle, P. J., & Mitchell, J. E. (1982) · PubMed · Cited by 29 · see citing works
Duplex scanning of the thyroid
Woodcock, J. P., Owen, G. M., Shedden, E. J., Hodgson, K. J., Macgregor, A. G., & Srivastava, A. (1985) · Ultrasound in Medicine & Biology · doi:10.1016/0301-5629(85)90037-7 · Cited by 21 · see citing works
Kaur, S., Parr, J. H., Ramsay, I. D., Hennebry, T. M., Jarvis, K. J., & Lester, E. (1988) · PubMed Central · Cited by 18 · see citing works
Bolognesi, M., Sacerdoti, D., Merkel, C. E., & Gatta, A. (1994) · Journal of Ultrasound in Medicine · doi:10.7863/jum.1994.13.12.945 · Cited by 18 · see citing works
Sponza, M., Fabris, B., Bertolotto, M., Ricci, C., & Armini, L. (1997) · PubMed · Cited by 12 · see citing works
[Echo-color Doppler in the study of hypothyroidism in the adult].
Lagalla, R., Caruso, G., Benza, I., Novara, V., & Calliada, F. (1993) · PubMed · Cited by 11 · see citing works
Effect of Lugolʼs iodine on the vascularity of thyroid gland in hyperthyroidism
RANGASWAMY, M., Padhy, A. K., Gopinath, P. G., Shukla, N. K., GUPTA, K., & KAPOOR, M. M. (1989) · Nuclear Medicine Communications · doi:10.1097/00006231-198909000-00007 · Cited by 10 · see citing works
Flagged first, then by citations
Cited by
Sorted by citations
Ross, D. S., Burch, H. B., Cooper, D. S., Greenlee, M. C., Laurberg, P., Maia, A. L., Rivkees, S. A., Samuels, M., Sosa, J. A., Stan, M. N., et al. (2016) · Thyroid® · doi:10.1089/thy.2016.0229 · Cited by 2,938 · see citing works
“This treatment is beneficial because it decreases thyroid blood flow, vascularity, and intraoperative blood loss during thyroidectomy (181,182).”
BackgroundBahn, R. S., Burch, H. B., Cooper, D. S., Garber, J. R., Greenlee, M. C., Klein, I., Laurberg, P., McDougall, I. R., Montori, V. M., Rivkees, S. A., et al. (2011) · Endocrine Practice · doi:10.4158/ep.17.3.456 · Cited by 1,098 · see citing works
The American Thyroid Association and American Association of Clinical Endocrinologists Taskforce on Hyperthyroidism and Other Causes of Thyrotoxicosis, Bahn, R. S., Burch, H. B., Cooper, D. S., Garber, J. R., Greenlee, M. C., Klein, I., Laurberg, P., McDougall, I. R., Montori, V. M., et al. (2011) · Thyroid · doi:10.1089/thy.2010.0417 · Cited by 898 · see citing works
Patel, K. N., Yip, L., Lubitz, C. C., Grubbs, E. G., Miller, B. S., Shen, W. T., Angelos, P., Chen, H., Doherty, G. M., Fahey, T. J., et al. (2020) · Annals of Surgery · doi:10.1097/sla.0000000000003580 · Cited by 553 · see citing works
Satoh, T., Isozaki, O., Suzuki, A., Wakino, S., Iburi, T., Tsuboi, K., Kanamoto, N., Otani, H., Furukawa, Y., Teramukai, S., et al. (2016) · Endocrine Journal · doi:10.1507/endocrj.ej16-0336 · Cited by 259 · see citing works
Erbil, Y., Ozluk, Y., Giriş, M., Salmaslıoglu, A., Issever, H., Barbaros, U., Kapran, Y., Özarmağan, S., & Tezelman, S. (2007) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2007-0229 · Cited by 157 · see citing works
Thyroid surgery: postoperative hematoma—prevention and treatment
Harding, J., Sebag, F. A., Sierra, M., Palazzo, F. F., & Henry, J. (2006) · Langenbeck s Archives of Surgery · doi:10.1007/s00423-006-0028-6 · Cited by 112 · see citing works
Hallgrímsson, P., Lovén, L., Westerdahl, J., & Bergenfelz, A. O. J. (2008) · Langenbeck s Archives of Surgery · doi:10.1007/s00423-008-0361-z · Cited by 72 · see citing works
Calissendorff, J., & Falhammar, H. (2017) · Endocrine · doi:10.1007/s12020-017-1461-8 · Cited by 67 · see citing works
Can Contrast Media Increase Organ Doses in CT Examinations? A Clinical Study
Amato, E., Salamone, I., Naso, S., Bottari, A., Gaeta, M., & Blandino, A. (2013) · American Journal of Roentgenology · doi:10.2214/ajr.12.8958 · Cited by 55 · see citing works
Maia, A. L., Scheffel, R. S., Meyer, E. L. D. S., Mazeto, G. M. F. D. S., de Carvalho, G. A., Graf, H., Vaisman, M., Maciel, L. M. Z., Ramos, H. E., Tincani, Á. J., et al. (2013) · Arquivos Brasileiros de Endocrinologia & Metabologia · doi:10.1590/s0004-27302013000300006 · Cited by 58 · see citing works
Novel Thyroidectomy Difficulty Scale Correlates with Operative Times
Schneider, D. F., Mazeh, H., Oltmann, S. C., Chen, H., & Sippel, R. S. (2014) · World Journal of Surgery · doi:10.1007/s00268-014-2489-z · Cited by 48 · see citing works
Predictive features associated with thyrotoxic storm and management
Bacuzzi, A., Dionigi, G., Guzzetti, L., Martino, A. I. D., Severgnini, P., & Cuffari, S. (2017) · Gland Surgery · doi:10.21037/gs.2017.07.01 · Cited by 42 · see citing works
Manouras, A., Markogiannakis, H., Kekis, P. B., Lagoudianakis, E., & Fleming, B. (2008) · Expert Review of Medical Devices · doi:10.1586/17434440.5.4.447 · Cited by 42 · see citing works
Total Thyroidectomy for Graves' Disease: Compliance with ATA Guidelines may not Always be Necessary
Shinall, M. C., Broome, J. T., Nookala, R., Shinall, J., Kiernan, C., Parks, L., & Solórzano, C. (2013) · Surgery · doi:10.1016/j.surg.2013.04.064 · Cited by 38 · see citing works
Is Potassium Iodide Solution Necessary Before Total Thyroidectomy for Graves Disease?
Shinall, M. C., Broome, J. T., Baker, A., & Solorzano, C. C. (2013) · Annals of Surgical Oncology · doi:10.1245/s10434-013-3126-z · Cited by 37 · see citing works
Treatment of adult Graves’ disease
Corvilain, B., Hamy, A., Brunaud, L., Borson‐Chazot, F., Orgiazzi, J., Hachmi, L. B. S., Semrouni, M., Rodien, P., & Lussey‐Lepoutre, C. (2018) · Annales d Endocrinologie · doi:10.1016/j.ando.2018.08.003 · Cited by 35 · see citing works
The Diagnosis and Management of Hyperthyroidism Consensus - Report of the Korean Thyroid Association
Yi, K. H., Moon, J. H., Kim, I.-J., Bom, H.-S., Lee, J., Chung, W. Y., Chung, J. H., & Shong, Y. K. (2013) · Journal of Korean Thyroid Association · doi:10.11106/jkta.2013.6.1.1 · Cited by 32 · see citing works
Huang, S., Liao, W., Lin, C., Sun, H. S., & Chow, N. (2015) · World Journal of Surgery · doi:10.1007/s00268-015-3298-8 · Cited by 32 · see citing works
Whalen, G. F., Sullivan, M. O., Maranda, L., Quinlan, R., & Larkin, A. C. (2016) · The American Journal of Surgery · doi:10.1016/j.amjsurg.2016.07.015 · Cited by 28 · see citing works
Erbil, Y., Giriş, M., Salmaslıoğlu, A., Özlük, Y., Barbaros, U., Yanık, B. T., Kapran, Y., Doğru‐Abbasoğlu, S., & Özarmağan, S. (2007) · Surgery · doi:10.1016/j.surg.2007.07.036 · Cited by 26 · see citing works
Assessing American Thyroid Association Guidelines for Total Thyroidectomy in Graves' Disease
Akram, S., Elfenbein, D. M., Chen, H., Schneider, D. F., & Sippel, R. S. (2019) · Journal of Surgical Research · doi:10.1016/j.jss.2019.07.029 · Cited by 25 · see citing works
Revisiting the role of surgery in the treatment of Graves’ disease
Cohen, O. M., Ronen, O., Khafif, A., Rodrigo, J. P., Simó, R., Pace‐Asciak, P., Randolph, G. W., Mikkelsen, L. H., Kowalski, L. P., Olsen, K. D., et al. (2021) · Clinical Endocrinology · doi:10.1111/cen.14653 · Cited by 24 · see citing works
Is minimally invasive, video-assisted thyroidectomy feasible in Graves’ disease?
Alesina, P. F., Singaporewalla, R. M., Eckstein, A. K., Lahner, H., & Walz, M. K. (2011) · Surgery · doi:10.1016/j.surg.2010.11.018 · Cited by 24 · see citing works
Huang, S.-M. (2003) · Archives of Surgery · doi:10.1001/archsurg.138.2.146 · Cited by 24 · see citing works
Safe incorporation of new technologies in thyroid surgery
Dionigi, G., Bacuzzi, A., Bertocchi, V., Carrafiello, G., Boni, L., Rovera, F. A., & Dionigi, R. (2008) · Expert Review of Medical Devices · doi:10.1586/17434440.5.6.747 · Cited by 23 · see citing works
Yılmaz, Y., Kamer, E., Üreyen, O., Sarı, E., Acar, T., & Karahallı, Ö. (2016) · Annals of Medicine and Surgery · doi:10.1016/j.amsu.2016.06.002 · Cited by 23 · see citing works
Hope, N., & Kelly, A. (2016) · European Thyroid Journal · doi:10.1159/000450976 · Cited by 23 · see citing works
Yabuta, T., Ito, Y., Hirokawa, M., Fukushima, M., INOUE, H., Tomoda, C., Higashiyama, T., Kihara, M., Uruno, T., Takamura, Y., et al. (2009) · Endocrine Journal · doi:10.1507/endocrj.k08e-240 · Cited by 19 · see citing works
Fischli, S., Lucchini, B., Müller, W. E. G., Slahor, L., & Henzen, C. (2016) · Swiss Medical Weekly · doi:10.4414/smw.2016.14243 · Cited by 19 · see citing works
Preoperative preparation for Graves’ disease
Xu, T., Zheng, X., & Wei, T. (2023) · Frontiers in Endocrinology · doi:10.3389/fendo.2023.1234056 · Cited by 15 · see citing works
Hassan, I., Dănilă, R., Aljabri, H., Hoffmann, S., Wunderlich, A. C., Karakas, E., & Zielke, A. (2008) · Endocrine · doi:10.1007/s12020-008-9076-8 · Cited by 14 · see citing works
Beta-blockers and the thyrotoxic patient for thyroid and non-thyroid surgery: A clinical review
Tay, S., Khoo, E., Tancharoen, C., & Lee, I. (2013) · OA Anaesthetics · doi:10.13172/2052-7853-1-1-491 · Cited by 12 · see citing works
Does Surgery Without Lugol’s Solution Pretreatment for Graves’ Disease Increase Surgical Morbidity?
Mercier, F., Bonal, M., Fanget, F., Maillard, L., Laplace, N., Peix, J., & Lifante, J. (2018) · World Journal of Surgery · doi:10.1007/s00268-017-4443-3 · Cited by 13 · see citing works
Lindner, K., Kußmann, J., & Fendrich, V. (2020) · World Journal of Surgery · doi:10.1007/s00268-020-05593-0 · Cited by 13 · see citing works
Surgical indications for toxic multinodular goitre.
Pisanu, A., Montisci, A., Cois, A., & Uccheddu, A. (2005) · PubMed · Cited by 11 · see citing works
Doppler evaluation of the thyroid in pediatric goiter
Mahmutyazıcıoğlu, K., & Turğut, M. (2003) · Journal of Clinical Ultrasound · doi:10.1002/jcu.10215 · Cited by 10 · see citing works
Iodine and Hyperthyroidism: A Double-Edged Sword
Braverman, K. D., & Pearce, E. N. (2024) · Endocrine Practice · doi:10.1016/j.eprac.2024.10.014 · Cited by 9 · see citing works
Ultrasonography of the Thyroid
Blum, M. (2015) · Europe PMC (PubMed Central) · Cited by 9 · see citing works
Approach to the patient with thyroid storm
Kopp, P. A., Giordani, I., Feldt‐Rasmussen, U., & Forget-Renaud, A. (2026) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/clinem/dgag054 · Cited by 9 · see citing works
Sutureless thyroidectomy for controlled toxic goiter: a single-institute experience
Shaaban, A., & Ramadan, R. (2017) · The Egyptian Journal of Surgery · doi:10.4103/1110-1121.199893 · Cited by 5 · see citing works
Anesthésie-réanimation dans la chirurgie de la glande thyroïde
Lebuffe, G., Andrieu, G., Jany, T., Carnaille, B. M. L., & Vallet, B. (2007) · EMC-Anesthésie réanimation/Encyclopédie médico-chirurgicale. Anesthésie, réanimation · doi:10.1016/s0246-0289(07)44728-4 · Cited by 4 · see citing works
Williams, R. T., & Angelos, P. (2012) · doi:10.1002/9781118444832.ch22 · Cited by 4 · see citing works
Clinical Applications of Thyroid Ultrasonography
Lin, J., Hsueh, C., Liu, F.-H., Chen, J., & Chang, H. (2006) · The Endocrinologist · doi:10.1097/01.ten.0000250186.27805.1b · Cited by 3 · see citing works
Anestesia y reanimación en la cirugía de la glándula tiroidea
Garot, M., Caiazzo, R. J., Andrieu, G., & Lebuffe, G. (2015) · EMC - Anestesia-Reanimación · doi:10.1016/s1280-4703(15)73874-0 · Cited by 3 · see citing works
Lugol's iodine in Graves' disease – Revisited
Reddy, A. C., & Mayilvaganan, S. (2016) · International Journal of Surgery · doi:10.1016/j.ijsu.2016.10.018 · Cited by 2 · see citing works
Pre-operative use of Lugol’s iodine in a case with toxic adenomatous goiter
Kulkarni, S., Murchite, S., Parab, S., Tiwari, V., & Rajagopal, A. (2021) · International Surgery Journal · doi:10.18203/2349-2902.isj20211845 · Cited by 2 · see citing works
Lushefski, K., Wolf, M., DOVE, J. T., Fluck, M. B., & Oxenberg, J. C. (2023) · The American Surgeon · doi:10.1177/00031348231192016 · Cited by 2 · see citing works
Comparison of Surgical Outcomes of Transoral Versus Open Thyroidectomy for Graves Disease
Wang, S.-H., Chao, W.-P., Lo, T.-Y., Ng, S., & Chen, Y. (2024) · Surgical Laparoscopy Endoscopy & Percutaneous Techniques · doi:10.1097/sle.0000000000001261 · Cited by 1 · see citing works
Bartalena, L., Gallo, D., Piantanida, E., & Tanda, M. L. (2026) · Expert Review of Endocrinology & Metabolism · doi:10.1080/17446651.2026.2676876 · Cited by 1 · see citing works
Patología tiroidea en atención primaria
González, A. L., Vázquez, Á. N., Carballido, F. C., Gómez, N. G., Rodríguez, M. L., & Carro, M. C. (2016) · FMC - Formación Médica Continuada en Atención Primaria · doi:10.1016/j.fmc.2015.12.012 · Cited by 1 · see citing works
Controversies in thyroid and parathyroid surgery
Shires, C. B., Parsons, A., Dewan, K., & Sebelik, M. (2025) · American Journal of Otolaryngology · doi:10.1016/j.amjoto.2025.104703 · Cited by 1 · see citing works
Endocrine Complications of Head and Neck Surgery
Hu, M. I.-N., & Sherman, S. I. (2009) · Elsevier eBooks · doi:10.1016/b978-141604220-4.50012-2 · Cited by 1 · see citing works
Thyroid Surgery in Paediatric Patients
Rivkees, S. A., Breuer, C. K., & Udelsman, R. (2012) · Wiley eBooks · doi:10.1002/9781118444832.ch4
Anestesia-rianimazione in chirurgia tiroidea
Garot, M., Caiazzo, R. J., Andrieu, G., & Lebuffe, G. (2015) · EMC - Anestesia-Rianimazione · doi:10.1016/s1283-0771(15)73954-x
Anestesia-rianimazione nella chirurgia della tiroide
Lebuffe, G., Andrieu, G., Jany, T., Carnaille, B. M. L., & Vallet, B. (2007) · EMC - Anestesia-Rianimazione · doi:10.1016/s1283-0771(07)70305-5
Shreyamsa, M., Mouli, V. S., Singh, K. R., Ramakant, P., & Mishra, A. (2018) · Surgery · doi:10.1016/j.surg.2018.02.021
Anestesia-reanimación en la cirugía de la glándula tiroidea
Lebuffe, G., Andrieu, G., Jany, T., Carnaille, B., & Vallet, B. (2007) · EMC - Anestesia-Reanimación · doi:10.1016/s1280-4703(07)70477-2
Ahn, D., & Koo, B. S. (2025) · Springer eBooks · doi:10.1007/978-981-96-1860-6_14
Ünlü, M. T., Çalışkan, O., Çetinoğlu, I., Sengul, Z., Arikan, H., Gerçelman, D., Aygün, N., & Uludağ, M. (2026) · Frontiers in Surgery · doi:10.3389/fsurg.2026.1755477
- Authors
- Ansaldo, G. L., Pretolesi, F., Varaldo, E., Meola, C., Minuto, M., Borgonovo, G., Derchi, L. E., & Torre, G. C.
- Affiliations
- Ansaldo (Italy) (IT)
- University of Genoa (IT)
- Corresponding author
- Torre, Gian Carlo
- Venue
- Journal of the American College of Surgeons
- Published
- 2000-12
- Volume
- 191
- Issue
- 6
- Pages
- 607-612
- ISSN
- 1072-7515 (ISSN-L)
- OpenAlex
- W1939645979
- Cited by
- 60
- References
- 17
- Citations by year
- 2026: 3 · 2025: 2 · 2024: 2 · 2023: 2 · 2021: 2 · 2020: 2 · 2019: 1 · 2018: 3 · 2017: 3 · 2016: 8 · 2015: 4 · 2014: 1 · 2013: 6 · 2012: 2
- FWCI
- 0.48
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Journal of the American College of Surgeons (publishedVersion)
- PubMed (publishedVersion)
- CINECA IRIS Institutial Research Information System (University of Genoa) (submittedVersion)
- Topics
- Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Thyroid Disorders and Treatments
- Health Sciences › Medicine › Surgery › Thyroid and Parathyroid Surgery
- Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Thyroid Cancer Diagnosis and Treatment
- Keywords
- Graves' disease, thyroid vascularization, thyroidectomy, thyroid blood flow
- MeSH terms
- Adult, Arteries, Combined Modality Therapy, Female, Graves Disease, Hemostatics, Humans, Iodides, Male, Methimazole, Middle Aged, Preoperative Care, Antithyroid Agents, Thyroid Function Tests, Thyroid Gland, Thyroidectomy, Vascular Resistance, Case-Control Studies, Blood Loss, Surgical, Drug Monitoring, Ultrasonography, Doppler
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
