title: Finding an alternative diagnosis does not justify increased use of CT-pulmonary angiography.
abstract: BACKGROUND
  The increased use of computed tomography pulmonary angiography (CTPA) is often justified by finding alternative diagnoses explaining patients' symptoms. However, this has not been rigorously examined.
  
  
  METHODS
  We retrospectively reviewed CTPA done at our center over an eleven year period (2000 - 2010) in patients with suspected pulmonary embolus (PE). We then reviewed in detail the medical records of a representative sample of patients in three index years - 2000, 2005 and 2008. We determined whether CTPA revealed pulmonary pathology other than PE that was not readily identifiable from the patient's history, physical examination and prior chest X-ray. We also assessed whether the use of pre-test probability guided diagnostic strategy for PE.
  
  
  RESULTS
  A total of 12,640 CTPA were performed at our center from year 2000 to 2010. The number of CTPA performed increased from 84 in 2000 to 2287 in 2010, a 27 fold increase. Only 7.6 percent of all CTPA and 3.2 percent of avoidable CTPAs (low or intermediate pre-test probability and negative D-dimer) revealed previously unknown findings of any clinical significance. When we compared 2008 to 2000 and 2005, more CTPAs were performed in younger patients (mean age (years) for 2000: 67, 2005: 63, and 2008: 60, (p=0.004, one-way ANOVA)). Patients were less acutely ill with fewer risk factors for PE. Assessment of pre-test probability of PE and D-dimer measurement were rarely used to select appropriate patients for CTPA (pre-test probability of PE documented in chart (% total) in year 2000: 4.1%, 2005: 1.6%, 2008: 3.1%).
  
  
  CONCLUSIONS
  Our data do not support the argument that increased CTPA use is justified by finding an alternative pulmonary pathology that could explain patients' symptoms. CTPA is being increasingly used as the first and only test for suspected PE.
authors: Division of Pulmonary, Critical Care and Sleep Medicine, The Long Island Jewish Medical Center, The Hofstra North Shore-LIJ School of Medicine, New Hyde Park, New York, NY 11040, USA.
authors: Subani
authors: S
authors: Chandra
authors: Pralay K
authors: PK
authors: Sarkar
authors: Divay
authors: D
authors: Chandra
authors: Nicole E
authors: NE
authors: Ginsberg
authors: Rubin I
authors: RI
authors: Cohen
mesh_terms: D000046:Academic Medical Centers / Q000706:statistics & numerical data; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods* / Q000706:statistics & numerical data*; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism; D006801:Humans; D008171:Lung Diseases / Q000000981:diagnostic imaging* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000453:epidemiology; D013902:Radiography, Thoracic / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000706:statistics & numerical data*; D019564:Unnecessary Procedures / Q000706:statistics & numerical data
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D
references: Radiology. 2010 Aug;256(2):625-32
references: 20551182
references: Acad Emerg Med. 2004 Jun;11(6):642-7
references: 15175202
references: Arch Intern Med. 2009 Nov 23;169(21):1961-5
references: 19933956
references: Ann Emerg Med. 2011 Nov;58(5):465-7
references: 21835500
references: Conn Med. 2010 Jan;74(1):5-9
references: 20175366
references: Radiology. 2003 Jun;227(3):776-85
references: 12702825
references: Radiol Med. 2008 Apr;113(3):373-84
references: 18493774
references: Radiology. 2010 Aug;256(2):334-7
references: 20656827
references: Am J Med. 2006 Dec;119(12):1048-55
references: 17145249
references: AJR Am J Roentgenol. 2008 Aug;191(2):471-4
references: 18647919
references: J Intern Med. 2010 Sep;268(3):218-31
references: 20626551
references: Arch Intern Med. 2009 Nov 23;169(21):1966-8
references: 19933957
references: J Nucl Med. 2011 Oct;52(10):1508-12
references: 21803837
references: Acta Radiol. 2012 Feb 1;53(1):39-43
references: 22114018
references: Radiology. 2007 Dec;245(3):742-50
references: 17923509
references: Chest. 2011 Aug;140(2):509-518
references: 21813530
references: Health Phys. 2008 Nov;95(5):502-7
references: 18849682
references: Am J Med Qual. 2012 Jan-Feb;27(1):74-9
references: 21666066
references: J Comput Assist Tomogr. 2008 May-Jun;32(3):421-5
references: 18520550
references: Intern Med J. 2011 Mar;41(3):258-63
references: 20214691
references: Ann Emerg Med. 2011 Nov;58(5):452-62.e3
references: 21835499
references: Ann Emerg Med. 2009 Jul;54(1):41-8
references: 18838194
references: Radiology. 2007 Jan;242(1):15-21
references: 17185658
references: Acad Radiol. 2009 Jun;16(6):708-17
references: 19427980