@article {Bier00035-2022, author = {Elianna A. Bier and Fawaz Alenezi and Junlan Lu and Ziyi Wang and Joseph G. Mammarappallil and Bryan O{\textquoteright}Sullivan-Murphy and Alaattin Erkanli and Bastiaan Driehuys and Sudarshan Rajagopal}, title = {Noninvasive diagnosis of pulmonary hypertension with hyperpolarised 129Xe magnetic resonance imaging and spectroscopy}, volume = {8}, number = {2}, elocation-id = {00035-2022}, year = {2022}, doi = {10.1183/23120541.00035-2022}, publisher = {European Respiratory Society}, abstract = {Background The diagnosis of pulmonary hypertension (PH) remains challenging. Pre- and post-capillary PH have different signatures on noninvasive 129Xe gas-exchange magnetic resonance imaging (MRI) and dynamic MR spectroscopy (MRS). We tested the accuracy of 129Xe MRI/MRS to diagnose PH status compared to right heart catheterisation (RHC).Methods 129Xe MRI/MRS from 93 subjects was used to develop a diagnostic algorithm, which was tested in 32 patients undergoing RHC on the same day (n=20) or within 5 months (42{\textpm}40 days) (n=12). Three expert readers, blinded to RHC, used 129Xe MRI/MRS to classify subjects as pre-capillary PH, post-capillary PH, no PH and no interstitial lung disease (ILD), or ILD.Results For pre-capillary PH, 129Xe MRI/MRS diagnostic accuracy was 75\% (95\% CI 66{\textendash}84) with a sensitivity of 67\% (95\% CI 54{\textendash}79) and a specificity of 86\% (95\% CI 75{\textendash}96); for post-capillary PH accuracy was 69\% (95\% CI 59{\textendash}78) with sensitivity of 54\% (95\% CI 34{\textendash}74) and specificity of 74\% (95\% CI 63{\textendash}84). The model performed well in straightforward cases of pre-capillary PH but was less accurate in its diagnosis in the presence of mixed disease, particularly in the presence of ILD or combined post- and pre-capillary PH.Conclusion This study demonstrates the potential to develop 129Xe MRI/MRS into a modality with good accuracy in detecting pre- and post-capillary PH. Furthermore, the combination of 129Xe dynamic MRS and gas-exchange MRI uniquely provide concurrent, noninvasive assessment of both haemodynamics and gas-exchange impairment that may aid in the detection of PH.Diagnostic models using 129Xe MRI/MRS metrics can noninvasively detect pre-capillary PH, post-capillary PH and ILD. The combination of 129Xe MRI/MRS provides a comprehensive assessment of haemodynamics and gas-exchange impairment in individual patients. https://bit.ly/3tDJw5P}, URL = {https://openres.ersjournals.com/content/8/2/00035-2022}, eprint = {https://openres.ersjournals.com/content/8/2/00035-2022.full.pdf}, journal = {ERJ Open Research} }