維基百科

亨氏單位

亨氏單位（英語：Hounsfield unit，縮寫：HU），為亨氏量表（Hounsfield scale）阻射率（英語：Radiodensity）的數量尺度單位，命名自X射線電腦斷層掃描的發明人高弗雷·豪斯費爾德（Godfrey Newbold Hounsfield）。亨氏單位常用於X射線電腦斷層掃描，因此又稱為CT值（CT number）。

定義

亨氏單位為其所測量之介質的線性衰減系數的線性映射，其定義將蒸餾水與空氣在標準溫度與標準壓力下的阻射率（英語：Radiodensity）分別設為0 HU和-1,000 HU。因此，在線性衰減系數介於平均值間的體素中，其亨氏單位為：[1]

 

其中 與 分別為水與空氣的線性衰減系數。[2]

由於空氣的線性衰減系數趨近於0，一個HU的變化相當於水線性衰減系數0.1%的變化。[2]

原理

由於X射線電腦斷層掃描的功能在於將生物（主要是陸上生物，如人類）的體內結構成像化，因此採納上述標準作為所有介質的參照依據。[2]

人體內各介質的亨氏單位值

亨氏單位僅適用於常見的雙能電腦斷層掃描（dual-energy CT scan），而不適用於錐狀射束電腦斷層掃描（cone beam CT scan）。[3]

介質 亨氏單位
空氣 −1,000
脂肪 −120至−90[4]
造影劑電腦斷層掃描（英語：Contrast CT）下的軟組織 +100至+300
骨骼 鬆質骨 +300至+400[5]
密質骨 +1,800至+1,900[5]
頭部外傷 前數小時 +75至+100[6]
3日後 +65至+85[6]
10-14日後 +35至+40[7]
其他血液 非凝血 +13[8]至+50[9]
凝血 +50[10]至+75[8][10]
胸腔積液 漏出液（英語：Transudate） +2至+15 [11]
滲出液 +4至+33[11]
其他體液 乳糜 −30[12]
水 0
尿液 −5至+15[4]
膽汁 −5至+15[4]
腦脊液 +15
膿瘍/膿 0[13]至+20[14] 或 +40[14]至+45[13]
黏液 0[15] - 130[16]（超過70HU時進入高衰減）[17][18]
薄壁組織 肺 −700至−600[19]
腎 +20至+45[4]
肝 60 ± 6[20]
淋巴結 +10至+20[21]
肌肉 +35至+55[4]
胸腺 +20至+40（兒童）[22]
+20至+120（成人）[22]
白質 +20至+30
灰質 +37至+45
膽結石 膽固醇石 +30至+100[23]
色素性膽結石 +90至+120[23]
異物（英語：Foreign body）[24] 一般窗戶玻璃 +500
鋁、瀝青、車窗玻璃、玻璃瓶與其他石類 +2,100至+2,300
石灰岩 +2,800
銅 +14,000
銀 +17,000
鋼 +20,000
金、鋼與黃銅 +30,000（可測量之上限）
耳垢 <0

亨氏單位常用於辨識腫瘤，以腎上腺腺瘤（英語：Adrenal adenoma）為例，當該腫瘤的阻射率（英語：Radiodensity）小於10 HU，則其脂肪成分偏高，代表該腫瘤有較大概率為良性腫瘤[25]。

參見

參考資料

  1. ^ Lev, Michael; Gonzalez, Rodolfo. CT Angiography and CT Perfusion Imaging. ScienceDirect. 2002 [2020-12-20]. （原始內容存檔於2020-11-12） （英語）. 
  2. ^ 2.0 2.1 2.2 DenOtter, Tami; Schubert, Johanna. Hounsfield Unit. 美國國家衛生院. 2020-05-11 [2020-12-20]. （原始內容存檔於2021-12-06） （英語）. 
  3. ^ De Vos, W.; Casselman, J.; Swennen, G.R.J. Cone-beam computerized tomography (CBCT) imaging of the oral and maxillofacial region: A systematic review of the literature. International Journal of Oral and Maxillofacial Surgery. 2009-06, 38 (6): 609–625. PMID 19464146. doi:10.1016/j.ijom.2009.02.028. 
  4. ^ 4.0 4.1 4.2 4.3 4.4 Page 83 in: Herbert Lepor. Prostatic Diseases. W.B. Saunders Company. 2000. ISBN 9780721674162. 
  5. ^ 5.0 5.1 Birur, NPraveen; Patrick, Sanjana; Gurushanth, Keerthi; Raghavan, AShubhasini; Gurudath, Shubha. Comparison of gray values of cone-beam computed tomography with hounsfield units of multislice computed tomography: An in vitro study. Indian Journal of Dental Research. 2017年, 28 (1): 66–70. ISSN 0970-9290. PMID 28393820. doi:10.4103/ijdr.IJDR_415_16. 
  6. ^ 6.0 6.1 Fig 3 in: Rao, Murali Gundu. Dating of Early Subdural Haematoma: A Correlative Clinico-Radiological Study. Journal of Clinical and Diagnostic Research. 2016, 10 (4): HC01–5. ISSN 2249-782X. PMC 4866129  . PMID 27190831. doi:10.7860/JCDR/2016/17207.7644. 
  7. ^ Dr Rohit Sharma; A.Prof Frank Gaillard. Subdural haemorrhage. Radiopaedia. [2018-08-14]. （原始內容存檔於2011-03-23）. 
  8. ^ 8.0 8.1 Page 263 in: Robert Fosbinder; Denise Orth. Essentials of Radiologic Science. Lippincott Williams & Wilkins. 2011. ISBN 9780781775540. 
  9. ^ page 20.17 in: F W Wright. Radiology of the Chest and Related Conditions. CRC Press. 2001. ISBN 9780415281416. 
  10. ^ 10.0 10.1 page 17 in: Dr. Avital Fast; Dorith Goldsher. Navigating the Adult Spine: Bridging Clinical Practice and Neuroradiology. Demos Medical Publishing. 2006. ISBN 9781934559741. 
  11. ^ 11.0 11.1 Cullu, Nesat; Kalemci, Serdar; Karakas, Omer; Eser, Irfan; Yalcin, Funda; Boyaci, Fatma Nurefsan; Karakas, Ekrem. Efficacy of CT in diagnosis of transudates and exudates in patients with pleural effusion. Diagnostic and Interventional Radiology. 2013, 20 (2): 116–20. ISSN 1305-3825. PMC 4463296  . PMID 24100060. doi:10.5152/dir.2013.13066. 
  12. ^ Page 342 in: Luca Saba; Jasjit S. Suri. Multi-Detector CT Imaging: Principles, Head, Neck, and Vascular Systems, Volume 1. CRC Press. 2013. ISBN 9781439893845. 
  13. ^ 13.0 13.1 P. Sanchez de Medina Alba; C. Santos Montón; N. Calvo; K. El Karzazi; T. González de la Huebra Labrador; R. Corrales; N. Alegre Borge; Salamanca/ES. Liver abscesses: where do they come from?A review of the main types of liver abscesses and the correlation between their causes and the radiologic findings. ECR 2014. 2014 [2020-12-17]. doi:10.1594/ecr2014/C-1927. （原始內容存檔於2019-01-12）. 
  14. ^ 14.0 14.1 Sasaki, Toru; Miyata, Rie; Hatai, Yoshiho; Makita, Kohzoh; Tsunoda, Koichi. Hounsfield unit values of retropharyngeal abscess-like lesions seen in Kawasaki disease. Acta Oto-Laryngologica. 2014, 134 (4): 437–440. ISSN 0001-6489. PMID 24512428. doi:10.3109/00016489.2013.878475. 
  15. ^ K SAGGAR, A AHLUWALIA; P SANDHU, V KALIA. Mucocoele Of The Appendix (PDF). Ind J Radiol Imag. 2006, 16 (2). [失效連結]
  16. ^ Gaeta, Michele; Vinci, Sergio; Minutoli, Fabio; Mazziotti, Silvio; Ascenti, Giorgio; Salamone, Ignazio; Lamberto, Salvatore; Blandino, Alfredo. CT and MRI findings of mucin-containing tumors and pseudotumors of the thorax: pictorial review. European Radiology. 2001, 12 (1): 181–189. ISSN 0938-7994. PMID 11868096. doi:10.1007/s003300100934. 
  17. ^ Subash S Phuyal; Mandeep Kumar MK Garg; Ritesh R Agarwal; Pankaj P Gupta; Arunaloke A Chakrabarti; Manavjit Singh MS Sandhu; Niranjan N Khandelwal. High-Attenuation Mucus Impaction in Patients With Allergic Bronchopulmonary Aspergillosis: Objective Criteria on High-Resolution Computed Tomography and Correlation With Serologic Parameters. Current Problems in Diagnostic Radiology. 2015-09-02. 
  18. ^ Agarwal, Ritesh; Sehgal, Inderpaul Singh; Dhooria, Sahajal; Aggarwal, Ashutosh. Radiologic Criteria for the Diagnosis of High-Attenuation Mucus in Allergic Bronchopulmonary Aspergillosis. Chest. 2016, 149 (4): 1109–1110. ISSN 0012-3692. PMID 27055707. doi:10.1016/j.chest.2015.12.043. 
  19. ^ Page 379 in: Ella A. Kazerooni; Barry H. Gross. Cardiopulmonary Imaging 4. Lippincott Williams & Wilkins. 2004. ISBN 9780781736558. 
  20. ^ page 210 in: Erwin Kuntz; Hans-Dieter Kuntz. Hepatology, Principles and Practice: History, Morphology, Biochemistry, Diagnostics, Clinic, Therapy. Springer Science & Business Media. 2006. ISBN 9783540289777. 
  21. ^ Page 58 in: G. Maatman. High-Resolution Computed Tomography of the Paranasal Sinuses and Pharynx and Related Regions: Impact of CT identification on diagnosis and patient management. Volume 12 of Series in Radiology. Springer Science & Business Media. 2012. ISBN 9789400942776. 
  22. ^ 22.0 22.1 Page 488 （頁面存檔備份，存於互聯網檔案館） in: Jean-Claude Givel; Marco Merlini; David B. Clarke; Michael Dusmet. Surgery of the Thymus: Pathology, Associated Disorders and Surgical Technique. Springer Science & Business Media. 2012. ISBN 9783642710766. 
  23. ^ 23.0 23.1 Rambow A, Staritz M, Wosiewitz U, Mildenburger P, Thelen M, Meyer zum Büschenfelde KH. Analysis of radiolucent gallstones by computed tomography for in vivo estimation of stone components. Eur J Clin Invest. 1990, 20 (4): 475–8. PMID 2121509. doi:10.1111/j.1365-2362.1990.tb01887.x. 
  24. ^ Bolliger, Stephan A.; Oesterhelweg, Lars; Spendlove, Danny; Ross, Steffen; Thali, Michael J. Is Differentiation of Frequently Encountered Foreign Bodies in Corpses Possible by Hounsfield Density Measurement?. Journal of Forensic Sciences. 2009, 54 (5): 1119–1122. ISSN 0022-1198. PMID 19627414. doi:10.1111/j.1556-4029.2009.01100.x. 
  25. ^ Perry J Horwich. Adrenal Adenoma Imaging. 2011-04-21 [2020-12-19] （英語）. 

參考書籍

  • Feeman, Timothy G. The Mathematics of Medical Imaging: A Beginner's Guide. Springer Undergraduate Texts in Mathematics and Technology. Springer. 2010. ISBN 978-0387927114. 

外部連結

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