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CT pulmonary angiogram compared with ventilation-perfusion scan for the diagnosis of pulmonary embolism in patients with cardiorespiratory disease
  1. Jonathan Costello, Specialist Registrar,
  2. Kerstin Hogg, Clinical Research Fellow
  1. Department of Emergency Medicine, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL, UK;


    A short cut review was carried out to establish whether VQ scanning has better utility than CT in investigating possible pulmonary embolus in patients with chronic respiratory disease. A total of 239 papers were found using the reported search, of which one presented the best evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of this best paper are tabulated. A clinical bottom line is stated.

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    Report by Jonathan Costello, Specialist Registrar
 Checked by Kerstin Hogg, Clinical Research Fellow

    Clinical scenario

    A 70 year old known COPD patient presents to your emergency department with pleuritic chest pain and dyspnoea suggestive of pulmonary embolus. Initial investigations do not exclude pulmonary embolus. As part of your diagnostic strategy, you wonder if V-Q scintigraphy has better diagnostic utility than CT for pulmonary embolus.

    Three part question

    In [patients with chronic respiratory disease] does [V-Q scintigraphy have greater diagnostic utility than computed tomography] in the [investigation of pulmonary embolus]?

    Search strategy

    Medline 1966-07/03 using the OVID interface. (exp Tomography, Spiral Computed OR exp Tomography, X-Ray Computed OR “CT”.mp) AND (exp Ventilation-Perfusion Ratio OR “VQ”.mp OR “V-Q”.mp OR Ventilation OR OR AND (exp pulmonary embolism OR pulmonary embol$.mp OR “PE”.mp OR Pulmonary infarct$.mp OR exp thromboembolism$ OR thromboembolism$.mp) LIMIT to human AND English.

    Search outcome

    Altogether 239 were papers found of which 238 did not address the exact question. One paper was of relevance (table 2).

    Table 2


    Surprisingly few comparative studies. Ultimately small number studied in the study in question. Rigid definition of study population and reporter bias pose difficulties in such a study group. Diagnostic utility of V-Q questionable because of high proportion of inconclusive results—resource and economic factors are thus of relevance.


    There is not enough evidence to support V-Q Scintigraphy as the initial investigation of choice in COPD patients.

    Report by Jonathan Costello, Specialist Registrar
 Checked by Kerstin Hogg, Clinical Research Fellow


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