Dhruv Patel MBBS, BSc, Presenter: Nothing to Disclose

Katherine L. Downey MBBS, BSc, Abstract Co-Author: Nothing to Disclose

Arjun Nair MBCHB, FRCR, Abstract Co-Author: Nothing to Disclose

Ioannis Vlahos MBBS, Abstract Co-Author: Research grant, Bayer AG Consultant, Siemens AG Consultant, Bayer AG

To evaluate established and postulated new criteria of PH on MDCT, their reliability and correlation with respect to RHC measurements of mean PA pressure (mPAP).

168 consecutive patients underwent bolus-triggered contrast enhanced CTPA (64 x0.6mm, 120kVp, mAs 160-310) and RHC as part of a tertiary center evaluation for suspected PH. Multiple standardized axial measurements of the pulmonary arteries were recorded by 2 readers. Mean reader measurements were correlated to mPAP. Existing criteria for the diagnosis of PH (main pulmonary artery (PA)>3cm, PA:Aorta ratio>1) were compared to new postulated criteria based upon more peripheral CT pulmonary arterial vasculature dimensions.  

Across all patients several highly significant correlations (p<0.01) between mPAP and axial arterial measurements were identified. In order of Pearson’s r correlation strength these were: main PA(0.62), right pulmonary artery (0.54), PA:Aorta ratio (0.54), left pulmonary artery (0.47), left lower lobe artery (0.34) and right interlobar artery (0.21). 109 patients had RHC determined PH (mPAP>25mmHg). The widely used existing criteria of PA>3cm and PA:AA>1 had sensitivities of only 69.4% and 68.5% respectively while both had specificities of 80.7%. A higher sensitivity and specificity can be achieved (74.1%, 82.5% respectively) if a new criterion of the sum of the axial maximum diameters of the right and left pulmonary arteries measuring ≥45mm is used. Considering more peripheral arteries, the sum of the right interlobar and left lower lobe artery ≥32mm yielded higher sensitivity still (79.6%) with comparable specificity to existing criteria (80.7%).  

  Corroboration in the largest right heart catheter correlated study to date suggests that the existing criteria for the CT diagnosis of pulmonary hypertension are relatively insensitive and could be improved without loss of specificity by using criteria based upon the size of second or third order divisions of the main pulmonary artery.  

Current CT criteria for PH based on small samples are insensitive and non-specific; we demonstrate new criteria with equal specificity but higher sensitivity using a large catheter correlated study.

Patel, D, Downey, K, Nair, A, Vlahos, I, Multidetector CT Quantitative Determination of Pulmonary Hypertension (PH): Evaluation of Old and Improved New Criteria in a Large Patient Cohort with Right Heart Catheterisation (RHC) Correlation.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9010381.html