Editing CT scan (section)

== Medical use ==
Since its introduction in the 1970s,<ref>{{Cite book |last1=Curry |first1=Thomas S. |url=https://books.google.com/books?id=W2PrMwHqXl0C |title=Christensen's Physics of Diagnostic Radiology |last2=Dowdey |first2=James E. |last3=Murry |first3=Robert C. |date=1990 |publisher=Lippincott Williams & Wilkins |isbn=978-0-8121-1310-5 |pages=289}}</ref> CT has become an important tool in [[medical imaging]] to supplement conventional [[X-ray]] imaging and [[medical ultrasonography]]. It has more recently been used for [[preventive medicine]] or [[screening (medicine)|screening]] for disease, for example, [[Virtual colonoscopy|CT colonography]] for people with a high risk of [[colon cancer]], or full-motion heart scans for people with a high risk of heart disease. Several institutions offer [[full-body scan]]s for the general population although this practice goes against the advice and official position of many professional organizations in the field primarily due to the [[radiation dose]] applied.<ref>{{Cite web |title=CT Screening |url=http://hps.org/documents/ctscreening_ps018-0.pdf |url-status=dead |archive-url=https://web.archive.org/web/20161013203907/http://hps.org/documents/ctscreening_ps018-0.pdf |archive-date=13 October 2016 |access-date=1 May 2018 |website=hps.org}}</ref>

The use of CT scans has increased dramatically over the last two decades in many countries.<ref name="Smith2009">{{Cite journal |vauthors=Smith-Bindman R, Lipson J, Marcus R, Kim KP, Mahesh M, Gould R, Berrington de González A, [[Diana Miglioretti|Miglioretti DL]] |date=December 2009 |title=Radiation dose associated with common computed tomography examinations and the associated lifetime attributable risk of cancer |journal=Archives of Internal Medicine |volume=169 |issue=22 |pages=2078–2086 |doi=10.1001/archinternmed.2009.427 |pmc=4635397 |pmid=20008690}}</ref> An estimated 72 million scans were performed in the United States in 2007 and more than 80 million in 2015.<ref name="Berrington2009">{{Cite journal |vauthors=Berrington de González A, Mahesh M, Kim KP, Bhargavan M, Lewis R, Mettler F, Land C |date=December 2009 |title=Projected cancer risks from computed tomographic scans performed in the United States in 2007 |journal=Arch. Intern. Med. |volume=169 |issue=22 |pages=2071–7 |doi=10.1001/archinternmed.2009.440 |pmc=6276814 |pmid=20008689}}</ref><ref>{{Cite web |title=Dangers of CT Scans and X-Rays – Consumer Reports |url=https://www.consumerreports.org/cro/magazine/2015/01/the-surprising-dangers-of-ct-sans-and-x-rays/index.htm |access-date=16 May 2018}}</ref>

=== Head ===
{{main|Computed tomography of the head}}
[[File:Computed tomography of human brain - large.png|thumb|Computed tomography of [[human brain]], from [[base of the skull]] to top. Taken with intravenous contrast medium. {{noprint|[[Commons: Scrollable computed tomography images of a normal brain]]}}]]
CT scanning of the head is typically used to detect [[infarction]] ([[stroke]]), [[Neoplasm|tumors]], [[calcification]]s, [[haemorrhage]], and bone [[Major trauma|trauma]].<ref>{{Cite book |last1=American Academy of Orthopaedic Surgeons |url=https://books.google.com/books?id=pUVwDwAAQBAJ&q=CT+scanning+of+the+head+is+typically+used+to+detect&pg=PA389 |title=Critical Care Transport |last2=American College of Emergency Physicians |last3=UMBC |date=2017-03-20 |publisher=Jones & Bartlett Learning |isbn=978-1-284-04099-9 |page=389}}</ref> Of the above, [[hypodense]] (dark) structures can indicate [[edema]] and infarction, hyperdense (bright) structures indicate calcifications and haemorrhage and bone trauma can be seen as disjunction in bone windows. Tumors can be detected by the swelling and anatomical distortion they cause, or by surrounding edema. CT scanning of the head is also used in CT-[[image guided surgery|guided]] [[stereotactic surgery]] and [[radiosurgery]] for treatment of intracranial tumors, [[arteriovenous malformation]]s, and other surgically treatable conditions using a device known as the [[N-localizer]].<ref>{{Cite book |last=Galloway |first=RL Jr. |url=https://books.google.com/books?id=ioxongEACAAJ |title=Image-Guided Neurosurgery |publisher=Elsevier |year=2015 |isbn=978-0-12-800870-6 |editor-last=Golby |editor-first=AJ |location=Amsterdam |pages=3–4 |chapter=Introduction and Historical Perspectives on Image-Guided Surgery}}</ref><ref>{{Cite book |last1=Tse |first1=VCK |url=https://books.google.com/books?id=uEghr21XY6wC |title=Principles and Practice of Stereotactic Radiosurgery |last2=Kalani |first2=MYS |last3=Adler |first3=JR |publisher=Springer |year=2015 |isbn=978-0-387-71070-9 |editor-last=Chin |editor-first=LS |location=New York |page=28 |chapter=Techniques of Stereotactic Localization |editor-last2=Regine |editor-first2=WF}}</ref><ref>{{Cite book |last1=Saleh |first1=H |title=Stereotactic Radiosurgery and Stereotactic Body Radiation Therapy |last2=Kassas |first2=B |publisher=CRC Press |year=2015 |isbn=978-1-4398-4198-3 |editor-last=Benedict |editor-first=SH |location=Boca Raton |pages=156–159 |chapter=Developing Stereotactic Frames for Cranial Treatment |editor-last2=Schlesinger |editor-first2=DJ |editor-last3=Goetsch |editor-first3=SJ |editor-last4=Kavanagh |editor-first4=BD |chapter-url=https://books.google.com/books?id=Pm3RBQAAQBAJ&q=Developing+Stereotactic+Frames+for+Cranial+Treatment&pg=PA153}}</ref><ref>{{Cite book |last1=Khan |first1=FR |url=https://books.google.com/books?id=mAN3MAEACAAJ&q=0444534970 |title=Brain Stimulation |last2=Henderson |first2=JM |series=Handbook of Clinical Neurology |publisher=Elsevier |year=2013 |isbn=978-0-444-53497-2 |editor-last=Lozano |editor-first=AM |volume=116 |location=Amsterdam |pages=28–30 |chapter=Deep Brain Stimulation Surgical Techniques |doi=10.1016/B978-0-444-53497-2.00003-6 |pmid=24112882 |editor-last2=Hallet |editor-first2=M}}</ref><ref>{{Cite book |last=Arle |first=J |url=https://books.google.com/books?id=cnF-2KCeR1sC&q=Textbook+of+Stereotactic+and+Functional+Neurosurgery |title=Textbook of Stereotactic and Functional Neurosurgery |publisher=Springer-Verlag |year=2009 |isbn=978-3-540-69959-0 |editor-last=Lozano |editor-first=AM |location=Berlin |pages=456–461 |chapter=Development of a Classic: the Todd-Wells Apparatus, the BRW, and the CRW Stereotactic Frames |editor-last2=Gildenberg |editor-first2=PL |editor-last3=Tasker |editor-first3=RR}}</ref><ref>{{Cite journal |vauthors=Brown RA, Nelson JA |date=June 2012 |title=Invention of the N-localizer for stereotactic neurosurgery and its use in the Brown-Roberts-Wells stereotactic frame |journal=Neurosurgery |volume=70 |issue=2 Supplement Operative |pages=173–176 |doi=10.1227/NEU.0b013e318246a4f7 |pmid=22186842 |s2cid=36350612}}</ref>

=== Neck ===
[[Contrast CT]] is generally the initial study of choice for [[neck mass]]es in adults.<ref name="UpToDate">{{Cite web |last=Daniel G Deschler, Joseph Zenga |title=Evaluation of a neck mass in adults |url=https://www.uptodate.com/contents/evaluation-of-a-neck-mass-in-adults |website=[[UpToDate]]}} This topic last updated: Dec 04, 2017.</ref> [[Computed tomography of the thyroid|CT of the thyroid]] plays an important role in the evaluation of [[thyroid cancer]].<ref name="Saeedan2016">{{Cite journal |last1=Bin Saeedan |first1=Mnahi |last2=Aljohani |first2=Ibtisam Musallam |last3=Khushaim |first3=Ayman Omar |last4=Bukhari |first4=Salwa Qasim |last5=Elnaas |first5=Salahudin Tayeb |year=2016 |title=Thyroid computed tomography imaging: pictorial review of variable pathologies |journal=Insights into Imaging |volume=7 |issue=4 |pages=601–617 |doi=10.1007/s13244-016-0506-5 |issn=1869-4101 |pmc=4956631 |pmid=27271508}}</ref> CT scan often incidentally finds thyroid abnormalities, and so is often the preferred investigation modality for thyroid abnormalities.<ref name="Saeedan2016" />

=== Lungs ===
{{Main|Computed tomography of the chest}}
A CT scan can be used for detecting both acute and chronic changes in the [[Parenchyma#Lung parenchyma|lung parenchyma]], the tissue of the [[lung]]s.<ref>{{Cite book |url=https://books.google.com/books?id=rQlDDwAAQBAJ |title=Computed Tomography of the Lung |publisher=Springer Berlin Heidelberg |year=2007 |isbn=978-3-642-39518-5 |pages=40, 47}}</ref> It is particularly relevant here because normal two-dimensional X-rays do not show such defects. A variety of techniques are used, depending on the suspected abnormality. For evaluation of chronic interstitial processes such as [[Pneumatosis#Lungs|emphysema]], and [[Pulmonary fibrosis#|fibrosis]],<ref>{{Cite book |url=https://books.google.com/books?id=VKATAQAAMAAJ&q=ct+of+lungs |title=High-resolution CT of the Lung |publisher=Lippincott Williams & Wilkins |year=2009 |isbn=978-0-7817-6909-9 |pages=81,568}}</ref> thin sections with high spatial frequency reconstructions are used; often scans are performed both on inspiration and expiration. This special technique is called [[high resolution CT]] that produces a sampling of the lung, and not continuous images.<ref>{{Cite book |last1=Martínez-Jiménez |first1=Santiago |url=https://books.google.com/books?id=QjouDwAAQBAJ&q=HRCT |title=Specialty Imaging: HRCT of the Lung E-Book |last2=Rosado-de-Christenson |first2=Melissa L. |last3=Carter |first3=Brett W. |date=2017-07-22 |publisher=Elsevier Health Sciences |isbn=978-0-323-52495-7}}</ref>

[[File:High-resolution computed tomographs of a normal thorax (thumbnail).jpg|thumb|left|link=Commons:Scrollable high-resolution computed tomography images of a normal thorax|[[High-resolution computed tomography|HRCT]] images of a normal thorax in [[Axial plane|axial]], [[Coronal plane|coronal]] and [[sagittal plane]]s, respectively. {{noprint|[[Commons:Scrollable high-resolution computed tomography images of a normal thorax|Click here to scroll through the image stacks.]]}}|120x120px]]
[[File:Bronchial wall thickness (T) and diameter (D).svg|thumb|upright|Bronchial wall thickness (T) and diameter of the bronchus (D)]]
[[Peribronchial cuffing|Bronchial wall thickening]] can be seen on lung CTs and generally (but not always) implies inflammation of the [[bronchus|bronchi]].<ref>{{Cite web |last=Yuranga Weerakkody |title=Bronchial wall thickening |url=https://radiopaedia.org/articles/bronchial-wall-thickening |url-status=dead |archive-url=https://web.archive.org/web/20180106063640/https://radiopaedia.org/articles/bronchial-wall-thickening |archive-date=2018-01-06 |access-date=2018-01-05 |website=[[Radiopaedia]]}}</ref>

An [[Incidental medical findings|incidentally]] found nodule in the absence of symptoms (sometimes referred to as an [[incidentaloma]]) may raise concerns that it might represent a tumor, either [[Benignity|benign]] or [[cancer|malignant]].<ref>{{Cite journal |vauthors=Wiener RS, Gould MK, Woloshin S, Schwartz LM, Clark JA |year=2012 |title="What do you mean, a spot?": A qualitative analysis of patients' reactions to discussions with their doctors about pulmonary nodules |journal=Chest |volume=143 |issue=3 |pages=672–677 |doi=10.1378/chest.12-1095 |pmc=3590883 |pmid=22814873}}</ref> Perhaps persuaded by fear, patients and doctors sometimes agree to an intensive schedule of CT scans, sometimes up to every three months and beyond the recommended guidelines, in an attempt to do surveillance on the nodules.<ref name="ACCPandATSfive">{{Citation |last1=American College of Chest Physicians |title=Five Things Physicians and Patients Should Question |date=September 2013 |url=http://www.choosingwisely.org/doctor-patient-lists/american-college-of-chest-physicians-and-american-thoracic-society/ |work=[[Choosing Wisely]] |archive-url=https://web.archive.org/web/20131103063427/http://www.choosingwisely.org/doctor-patient-lists/american-college-of-chest-physicians-and-american-thoracic-society/ |publisher=American College of Chest Physicians and American Thoracic Society |access-date=6 January 2013 |archive-date=3 November 2013 |last2=American Thoracic Society |author-link=American College of Chest Physicians |author-link2=American Thoracic Society |url-status=live}}, which cites
*{{cite journal |vauthors=MacMahon H, Austin JH, Gamsu G, Herold CJ, Jett JR, Naidich DP, Patz EF, Swensen SJ |s2cid=14498160 |title=Guidelines for Management of Small Pulmonary Nodules Detected on CT Scans: A Statement from the Fleischner Society1 |journal=Radiology |volume=237 |issue=2 |pages=395–400 |year=2005 |pmid=16244247 |doi=10.1148/radiol.2372041887}}
*{{cite journal |vauthors = Gould MK, Fletcher J, Iannettoni MD, Lynch WR, Midthun DE, Naidich DP, Ost DE |title=Evaluation of Patients with Pulmonary Nodules: When is It Lung Cancer?* |journal=Chest |volume=132 |issue=3_suppl |pages=108S–130S |year=2007 |pmid=17873164 |doi=10.1378/chest.07-1353 |author8=American College of Chest Physicians |s2cid=16449420}}
*{{cite journal |vauthors=Smith-Bindman R, Lipson J, Marcus R, Kim KP, Mahesh M, Gould R, Berrington de González A, [[Diana Miglioretti|Miglioretti DL]] |title=Radiation Dose Associated with Common Computed Tomography Examinations and the Associated Lifetime Attributable Risk of Cancer |journal=Archives of Internal Medicine |volume=169 |issue=22 |pages=2078–2086 |year=2009 |pmid=20008690 |pmc=4635397 |doi=10.1001/archinternmed.2009.427 }}
*{{cite journal |vauthors=Wiener RS, Gould MK, Woloshin S, Schwartz LM, Clark JA |title="What do you mean, a spot?": A qualitative analysis of patients' reactions to discussions with their doctors about pulmonary nodules |journal=Chest |volume=143 |issue=3 |pages=672–677 |year=2012 |pmid=22814873 |pmc=3590883 |doi=10.1378/chest.12-1095}}</ref> However, established guidelines advise that patients without a prior history of cancer and whose solid nodules have not grown over a two-year period are unlikely to have any malignant cancer.<ref name="ACCPandATSfive" /> For this reason, and because no research provides supporting evidence that intensive surveillance gives better outcomes, and because of risks associated with having CT scans, patients should not receive CT screening in excess of those recommended by established guidelines.<ref name="ACCPandATSfive" />

=== Angiography ===
[[File:SADDLE PE.JPG|thumb|Example of a CTPA, demonstrating a saddle [[pulmonary embolism|embolus]] (dark horizontal line) occluding the [[pulmonary artery|pulmonary arteries]] (bright white triangle)]]
{{Main|Computed tomography angiography}}

[[Computed tomography angiography]] (CTA) is a type of [[contrast CT]] to visualize the [[arteries]] and [[vein]]s throughout the body.<ref>{{Citation |last1=McDermott |first1=M. |title=Chapter 10 – Critical care in acute ischemic stroke |date=2017-01-01 |journal=Handbook of Clinical Neurology |volume=140 |pages=153–176 |editor-last=Wijdicks |editor-first=Eelco F. M. |series=Critical Care Neurology Part I |publisher=Elsevier |doi=10.1016/b978-0-444-63600-3.00010-6 |pmid=28187798 |last2=Jacobs |first2=T. |last3=Morgenstern |first3=L. |editor2-last=Kramer |editor2-first=Andreas H.}}</ref> This ranges from arteries serving the [[brain]] to those bringing blood to the [[lung]]s, [[kidney]]s, [[arm]]s and [[leg]]s. An example of this type of exam is [[CT pulmonary angiogram]] (CTPA) used to diagnose [[pulmonary embolism]] (PE). It employs computed tomography and an [[iodinated contrast|iodine-based contrast agent]] to obtain an image of the [[pulmonary artery|pulmonary arteries]].<ref>{{Cite web |date=19 November 2019 |title=Computed Tomography Angiography (CTA) |url=https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/computed-tomography-angiography-cta |access-date=2021-03-21 |website=www.hopkinsmedicine.org}}</ref><ref>{{Cite journal |last1=Zeman |first1=R K |last2=Silverman |first2=P M |last3=Vieco |first3=P T |last4=Costello |first4=P |date=1995-11-01 |title=CT angiography. |journal=American Journal of Roentgenology |volume=165 |issue=5 |pages=1079–1088 |doi=10.2214/ajr.165.5.7572481 |issn=0361-803X |pmid=7572481 |doi-access=free}}</ref><ref>{{Cite book |last1=Ramalho |first1=Joana |url=https://books.google.com/books?id=FKdMAgAAQBAJ&q=cta+is+an+imaging |title=Vascular Imaging of the Central Nervous System: Physical Principles, Clinical Applications, and Emerging Techniques |last2=Castillo |first2=Mauricio |date=2014-03-31 |publisher=John Wiley & Sons |isbn=978-1-118-18875-0 |page=69}}</ref> CT scans can reduce the risk of angiography by providing clinicians with more information about the positioning and number of clots prior to the procedure.<ref>{{Cite journal |last1=Jones |first1=Daniel A. |last2=Beirne |first2=Anne-Marie |last3=Kelham |first3=Matthew |last4=Rathod |first4=Krishnaraj S. |last5=Andiapen |first5=Mervyn |last6=Wynne |first6=Lucinda |last7=Godec |first7=Thomas |last8=Forooghi |first8=Nasim |last9=Ramaseshan |first9=Rohini |last10=Moon |first10=James C. |last11=Davies |first11=Ceri |last12=Bourantas |first12=Christos V. |last13=Baumbach |first13=Andreas |last14=Manisty |first14=Charlotte |last15=Wragg |first15=Andrew |date=2023-10-31 |title=Computed Tomography Cardiac Angiography Before Invasive Coronary Angiography in Patients With Previous Bypass Surgery: The BYPASS-CTCA Trial |journal=Circulation |language=en |volume=148 |issue=18 |pages=1371–1380 |doi=10.1161/CIRCULATIONAHA.123.064465 |issn=0009-7322 |pmc=11139242 |pmid=37772419}}</ref><ref>{{Cite journal |date=6 August 2024 |title=CT scan reduces the complications of angiography after bypass surgery |url=https://evidence.nihr.ac.uk/alert/ct-scan-reduces-the-complications-of-angiography-after-bypass-surgery/ |journal=NIHR Evidence|doi=10.3310/nihrevidence_63153 |doi-access=free }}</ref>  

=== Cardiac ===
A CT scan of the heart is performed to gain knowledge about cardiac or coronary anatomy.<ref>{{Cite web |title=Cardiac CT Scan – NHLBI, NIH |url=https://www.nhlbi.nih.gov/health/health-topics/topics/ct |url-status=live |archive-url=https://web.archive.org/web/20171201032800/https://www.nhlbi.nih.gov/health/health-topics/topics/ct |archive-date=2017-12-01 |access-date=2017-11-22 |website=www.nhlbi.nih.gov}}</ref> Traditionally, cardiac CT scans are used to detect, diagnose, or follow up [[coronary artery disease]].<ref name="Wichmann">{{Cite web |last=Wichmann |first=Julian L. |title=Cardiac CT {{!}} Radiology Reference Article {{!}} Radiopaedia.org |url=https://radiopaedia.org/articles/cardiac-ct-1 |url-status=dead |archive-url=https://web.archive.org/web/20171201040626/https://radiopaedia.org/articles/cardiac-ct-1 |archive-date=2017-12-01 |access-date=2017-11-22 |website=radiopaedia.org}}</ref> More recently CT has played a key role in the fast-evolving field of [[Interventional cardiology|transcatheter structural heart interventions]], more specifically in the transcatheter repair and replacement of heart valves.<ref>{{Cite journal |last1=Marwan |first1=Mohamed |last2=Achenbach |first2=Stephan |date=February 2016 |title=Role of Cardiac CT Before Transcatheter Aortic Valve Implantation (TAVI) |journal=Current Cardiology Reports |volume=18 |issue=2 |pages=21 |doi=10.1007/s11886-015-0696-3 |issn=1534-3170 |pmid=26820560 |s2cid=41535442}}</ref><ref>{{Cite journal |last1=Moss |first1=Alastair J. |last2=Dweck |first2=Marc R. |last3=Dreisbach |first3=John G. |last4=Williams |first4=Michelle C. |last5=Mak |first5=Sze Mun |last6=Cartlidge |first6=Timothy |last7=Nicol |first7=Edward D. |last8=Morgan-Hughes |first8=Gareth J. |date=2016-11-01 |title=Complementary role of cardiac CT in the assessment of aortic valve replacement dysfunction |journal=Open Heart |volume=3 |issue=2 |pages=e000494 |doi=10.1136/openhrt-2016-000494 |issn=2053-3624 |pmc=5093391 |pmid=27843568}}</ref><ref>{{Cite journal |last1=Thériault-Lauzier |first1=Pascal |last2=Spaziano |first2=Marco |last3=Vaquerizo |first3=Beatriz |last4=Buithieu |first4=Jean |last5=Martucci |first5=Giuseppe |last6=Piazza |first6=Nicolo |date=September 2015 |title=Computed Tomography for Structural Heart Disease and Interventions |journal=Interventional Cardiology Review |volume=10 |issue=3 |pages=149–154 |doi=10.15420/ICR.2015.10.03.149 |issn=1756-1477 |pmc=5808729 |pmid=29588693}}</ref>

The main forms of cardiac CT scanning are:
*[[Coronary CT angiography]] (CCTA): the use of CT to assess the [[coronary artery|coronary arteries]] of the [[heart]]. The subject receives an [[intravenous injection]] of [[radiocontrast]], and then the heart is scanned using a high-speed CT scanner, allowing radiologists to assess the extent of occlusion in the coronary arteries, usually to diagnose coronary artery disease.<ref>{{Cite book |last=Passariello |first=Roberto |url=https://books.google.com/books?id=eR5USB6sRU4C&q=ct+angiography |title=Multidetector-Row CT Angiography |date=2006-03-30 |publisher=Springer Science & Business Media |isbn=978-3-540-26984-7}}</ref><ref>{{Cite web |last1=Radiological Society of North America |last2=American College of Radiology |title=Coronary Computed Tomography Angiography (CCTA) |url=https://www.radiologyinfo.org/en/info.cfm?pg=angiocoroct |access-date=2021-03-19 |website=www.radiologyinfo.org}}</ref>
*[[Coronary CT calcium scan]]: also used for the assessment of severity of coronary artery disease. Specifically, it looks for calcium deposits in the coronary arteries that can narrow arteries and increase the risk of a heart attack.<ref name="mayo">{{Cite web |title=Heart scan (coronary calcium scan) |url=http://www.mayoclinic.org/tests-procedures/heart-scan/basics/definition/prc-20015000 |url-status=live |archive-url=https://web.archive.org/web/20150905084216/http://www.mayoclinic.org/tests-procedures/heart-scan/basics/definition/prc-20015000 |archive-date=5 September 2015 |access-date=9 August 2015 |publisher=Mayo Clinic}}</ref> A typical coronary CT calcium scan is done without the use of radiocontrast, but it can possibly be done from contrast-enhanced images as well.<ref name="van der BijlJoemai2010">{{Cite journal |last1=van der Bijl |first1=Noortje |last2=Joemai |first2=Raoul M.S. |last3=Geleijns |first3=Jacob |last4=Bax |first4=Jeroen J. |last5=Schuijf |first5=Joanne D. |last6=de Roos |first6=Albert |last7=Kroft |first7=Lucia J.M. |year=2010 |title=Assessment of Agatston Coronary Artery Calcium Score Using Contrast-Enhanced CT Coronary Angiography |journal=American Journal of Roentgenology |volume=195 |issue=6 |pages=1299–1305 |doi=10.2214/AJR.09.3734 |issn=0361-803X |pmid=21098187}}</ref>

To better visualize the anatomy, post-processing of the images is common.<ref name="Wichmann" /> Most common are multiplanar reconstructions (MPR) and [[volume rendering]]. For more complex anatomies and procedures, such as heart valve interventions, a true [[3D reconstruction]] or a 3D print is created based on these CT images to gain a deeper understanding.<ref>{{Cite journal |last1=Vukicevic |first1=Marija |last2=Mosadegh |first2=Bobak |last3=Min |first3=James K. |last4=Little |first4=Stephen H. |date=February 2017 |title=Cardiac 3D Printing and its Future Directions |journal=JACC: Cardiovascular Imaging |volume=10 |issue=2 |pages=171–184 |doi=10.1016/j.jcmg.2016.12.001 |issn=1876-7591 |pmc=5664227 |pmid=28183437}}</ref><ref>{{Cite journal |last1=Wang |first1=D. D. |last2=Eng |first2=M. |last3=Greenbaum |first3=A. |last4=Myers |first4=E. |last5=Forbes |first5=M. |last6=Pantelic |first6=M. |last7=Song |first7=T. |last8=Nelson |first8=C. |last9=Divine |first9=G. |last10=Taylor |first10=A. |last11=Wyman |first11=J. |last12=Guerrero |first12=M. |last13=Lederman |first13=R. J. |last14=Paone |first14=G. |last15=O'Neill |first15=W. |year=2016 |title=Innovative Mitral Valve Treatment with 3D Visualization at Henry Ford |url=http://www.materialise.com/en/blog/innovative-mitral-valve-treatment-3d-visualization-at-henry-ford |url-status=dead |journal=JACC: Cardiovascular Imaging |volume=9 |issue=11 |pages=1349–1352 |doi=10.1016/j.jcmg.2016.01.017 |pmc=5106323 |pmid=27209112 |archive-url=https://web.archive.org/web/20171201043336/http://www.materialise.com/en/blog/innovative-mitral-valve-treatment-3d-visualization-at-henry-ford |archive-date=2017-12-01 |access-date=2017-11-22}}</ref><ref>{{Cite journal |last1=Wang |first1=Dee Dee |last2=Eng |first2=Marvin |last3=Greenbaum |first3=Adam |last4=Myers |first4=Eric |last5=Forbes |first5=Michael |last6=Pantelic |first6=Milan |last7=Song |first7=Thomas |last8=Nelson |first8=Christina |last9=Divine |first9=George |date=November 2016 |title=Predicting LVOT Obstruction After TMVR |journal=JACC: Cardiovascular Imaging |volume=9 |issue=11 |pages=1349–1352 |doi=10.1016/j.jcmg.2016.01.017 |issn=1876-7591 |pmc=5106323 |pmid=27209112}}</ref><ref>{{Cite journal |last1=Jacobs |first1=Stephan |last2=Grunert |first2=Ronny |last3=Mohr |first3=Friedrich W. |last4=Falk |first4=Volkmar |date=February 2008 |title=3D-Imaging of cardiac structures using 3D heart models for planning in heart surgery: a preliminary study |journal=Interactive Cardiovascular and Thoracic Surgery |volume=7 |issue=1 |pages=6–9 |doi=10.1510/icvts.2007.156588 |issn=1569-9285 |pmid=17925319 |doi-access=free}}</ref>

=== Abdomen and pelvis ===
[[File:CT of a normal abdomen and pelvis, thumbnail.png|link=Commons:Scrollable computed tomography images of a normal abdomen and pelvis|thumb|CT scan of a normal abdomen and pelvis, in [[sagittal plane]], [[Coronal plane|coronal]] and [[Axial plane|axial]] planes, respectively. {{noprint|[[Commons:Scrollable computed tomography images of a normal abdomen and pelvis|<small>Click here to scroll through the image stacks.</small>]]}}|160x160px]]
{{Main|Computed tomography of the abdomen and pelvis}}
CT is an accurate technique for diagnosis of [[Human abdomen|abdominal]] diseases like [[Crohn's disease]],<ref>{{Cite journal |last1=Furukawa |first1=Akira |last2=Saotome |first2=Takao |last3=Yamasaki |first3=Michio |last4=Maeda |first4=Kiyosumi |last5=Nitta |first5=Norihisa |last6=Takahashi |first6=Masashi |last7=Tsujikawa |first7=Tomoyuki |last8=Fujiyama |first8=Yoshihide |last9=Murata |first9=Kiyoshi |last10=Sakamoto |first10=Tsutomu |date=2004-05-01 |title=Cross-sectional Imaging in Crohn Disease |journal=RadioGraphics |volume=24 |issue=3 |pages=689–702 |doi=10.1148/rg.243035120 |issn=0271-5333 |pmid=15143222 |doi-access=free}}</ref> GIT bleeding, and diagnosis and staging of cancer, as well as follow-up after cancer treatment to assess response.<ref>{{Cite book |url=https://books.google.com/books?id=r3uK7sSZUmcC |title=CT of the Acute Abdomen |publisher=Springer Berlin Heidelberg |year=2011 |isbn=978-3-540-89232-8 |pages=37}}</ref> It is commonly used to investigate [[acute abdominal pain]].<ref>{{Cite book |last1=Jay P Heiken |chapter-url=https://books.google.com/books?id=CSy5BQAAQBAJ&pg=PA3 |title=Diseases of the Abdomen and Pelvis |last2=Douglas S Katz |publisher=Springer Milan |year=2014 |isbn=978-88-470-5659-6 |editor-last=J. Hodler |page=3 |chapter=Emergency Radiology of the Abdomen and Pelvis: Imaging of the Nontraumatic and Traumatic Acute Abdomen |editor-last2=R. A. Kubik-Huch |editor-last3=G. K. von Schulthess |editor-last4=Ch. L. Zollikofer}}</ref>

Non-contrast-enhanced CT scans are the gold standard for diagnosing [[kidney stone disease]].<ref>{{Cite book |last1=Skolarikos |first1=A |url=https://uroweb.org/guidelines/urolithiasis |title=EAU Guidelines on Urolithiasis |last2=Neisius |first2=A |last3=Petřík |first3=A |last4=Somani |first4=B |last5=Thomas |first5=K |last6=Gambaro |first6=G |date=March 2022 |publisher=[[European Association of Urology]] |isbn=978-94-92671-16-5 |location=Amsterdam}}</ref> They allow clinicians to estimate the size, volume, and density of stones, helping to guide further treatment; with size being especially important in predicting the time to spontaneous passage of a stone.<ref>{{Cite journal |last1=Miller |first1=Oren F. |last2=Kane |first2=Christopher J. |date=September 1999 |title=Time to stone passage for observed ureteral calculi: a guide for patient education |journal=Journal of Urology |volume=162 |issue=3 Part 1 |pages=688–691 |doi=10.1097/00005392-199909010-00014 |pmid=10458343}}</ref>

=== Axial skeleton and extremities ===

For the [[axial skeleton]] and [[Limb (anatomy)|extremities]], CT is often used to image complex [[fracture (bone)|fractures]], especially ones around joints, because of its ability to reconstruct the area of interest in multiple planes. Fractures, ligamentous injuries, and [[Dislocation (medicine)|dislocations]] can easily be recognized with a 0.2&nbsp;mm resolution.<ref>{{Cite web |title=Ankle Fractures |url=http://orthoinfo.aaos.org/topic.cfm?topic=A00391 |url-status=dead |archive-url=https://web.archive.org/web/20100530103553/http://orthoinfo.aaos.org/topic.cfm?topic=A00391 |archive-date=30 May 2010 |access-date=30 May 2010 |website=orthoinfo.aaos.org |publisher=American Association of Orthopedic Surgeons}}</ref><ref>{{Cite journal |last=Buckwalter, Kenneth A. |display-authors=etal |date=11 September 2000 |title=Musculoskeletal Imaging with Multislice CT |journal=American Journal of Roentgenology |volume=176 |issue=4 |pages=979–986 |doi=10.2214/ajr.176.4.1760979 |pmid=11264094}}</ref> With modern dual-energy CT scanners, new areas of use have been established, such as aiding in the diagnosis of [[gout]].<ref>{{Cite journal |last1=Ramon |first1=André |last2=Bohm-Sigrand |first2=Amélie |last3=Pottecher |first3=Pierre |last4=Richette |first4=Pascal |last5=Maillefert |first5=Jean-Francis |last6=Devilliers |first6=Herve |last7=Ornetti |first7=Paul |date=2018-03-01 |title=Role of dual-energy CT in the diagnosis and follow-up of gout: systematic analysis of the literature |journal=Clinical Rheumatology |volume=37 |issue=3 |pages=587–595 |doi=10.1007/s10067-017-3976-z |issn=0770-3198 |pmid=29350330 |s2cid=3686099}}</ref>

=== Biomechanical use ===
CT is used in [[biomechanics]] to quickly reveal the geometry, anatomy, [[density]] and [[Modulus of elasticity|elastic moduli]] of biological tissues.<ref>{{Cite journal |last=Keaveny |first=Tony M. |date=March 2010 |title=Biomechanical computed tomography-noninvasive bone strength analysis using clinical computed tomography scans |journal=Annals of the New York Academy of Sciences |volume=1192 |issue=1 |pages=57–65 |bibcode=2010NYASA1192...57K |doi=10.1111/j.1749-6632.2009.05348.x |issn=1749-6632 |pmid=20392218 |s2cid=24132358}}</ref><ref>{{Cite book |last1=Barber |first1=Asa |url=https://books.google.com/books?id=shSMDwAAQBAJ&q=CT+is+used+in+biomechanics+to |title=Computed Tomography Based Biomechanics |last2=Tozzi |first2=Gianluca |last3=Pani |first3=Martino |date=2019-03-07 |publisher=Frontiers Media SA |isbn=978-2-88945-780-9 |page=20}}</ref>