Dual-energy computed tomography in the assessment of vascular and parenchymal enhancement in suspected pulmonary hypertension.

PURPOSE: To evaluate quantitative differences in central pulmonary artery (PA) and pulmonary global and regional enhancement in patients with and without pulmonary hypertension (PH) using dual-energy computed tomography (DECT). MATERIALS AND METHODS: We retrospectively studied 391 thoracic DECT studies and identified 89 patients with PA pressure (PAP) data and a pulmonary angiogram. PH was defined as a mean PAP of ≥25 mm Hg on right heart catheterization (RHC) (n=19) or a systolic PAP of ≥40 mm Hg on echocardiography (n=20). PH absence was defined by entirely normal echocardiography or RHC (n=50). PA enhancement (PAenh) was calculated from DECT iodine images. Volumetric enhancement of each whole lung (WLenh), 6 standard lung regions (RLenh), and 24 two-dimensional standardized regions of interest (ROIenh) was performed in each patient using pulmonary blood volume analysis. RESULTS: Mean PAenh was greater in PH patients compared with controls (272 vs. 252 HU, P<0.05), with a reciprocal reduction in mean WLenh (27 vs. 32 HU, P<0.01). Mean ROIenh (n=2058) confirmed lower parenchymal enhancement in PH (27 vs. 32 HU, P<0.001), with greater mean ROIenh standard deviation (10.5 vs. 9.3, P<0.001). Mean intrapatient pulmonary enhancement variability was greater in PH patients than in controls for 6 RLenh (variance 37 vs. 22, P=0.02) and 24 ROIenh measures (variance 188 vs. 130, P=0.04). RLenh and ROIenh variance correlated with RHC pulmonary vascular resistance (PVR) (r=0.44, 0.48; P=0.04, 0.03, respectively). A ratio of PAenh/WLenh distinguished PH from non-PH patients (10.9 vs. 8.4, P<0.001) and correlated best with PVR (r=0.59, P=0.004). CONCLUSIONS: PH patients demonstrate increased PAenh with a reciprocal reduction and greater variation in parenchymal enhancement; a DECT ratio of central to parenchymal enhancement correlates with PVR and may help identify PH.

The GH-2004 project: the response of IGF1 and type III pro-collagen to the administration of exogenous GH in non-Caucasian amateur athletes.

CONTEXT: The GH-2000 team proposed a method based on IGF1 and type III pro-collagen (P-III-P) to detect exogenously administered GH. As previous studies involved predominantly white European athletes, it is important to assess whether the response of these markers to recombinant human GH (rhGH) differs with ethnicity. OBJECTIVE: To examine the response of serum IGF1 and P-III-P and GH-2000 score to rhGH in non-Caucasian amateur athletes. DESIGN: Double-blind placebo-controlled rhGH administration study. SETTING: Wellcome Trust Clinical Research Facility, Southampton General Hospital. SUBJECTS: The study included 31 male and 14 female amateur athletes of different ethnicities. Intervention The subjects were assigned to treatment with placebo or 0.1 IU/kg per day (low dose) or 0.2 IU/kg per day (high dose) rhGH for 28 days. Blood was collected weekly during treatment and on days 35, 42 and 84 during the washout period. Serum IGF1 and P-III-P were measured, and GH-2000 score was calculated. RESULTS: IGF1, P-III-P and GH-2000 score rose in response to both low- and high-dose GH in both men and women. When compared with the Caucasian volunteers of the previous GH-2000 study, mean baseline and placebo-treated P-III-P and GH-2000 score were lower in GH-2004 men and women. Post-GH, however, peak IGF1 or P-III-P did not differ between studies but the peak GH-2000 score was lower in GH-2004 men. There was no difference between studies in the maximal change in IGF1, P-III-P and GH-2000 score in response to GH in either gender. CONCLUSIONS: These data do not support a significant ethnic effect on the peak or maximal response to rhGH.