Chronic thromboembolic pulmonary hypertension: pre- and postoperative assessment with breath-hold MR imaging techniques.
OBJECTIVE
To evaluate the potential of breath-hold magnetic resonance (MR) imaging techniques in morphologic and functional assessment of patients with chronic thromboembolic pulmonary hypertension (CTEPH) before and after surgery.


METHODS
Thirty-four patients with CTEPH were examined before and after pulmonary thromboendarterectomy (PTE). For morphologic assessment, contrast material-enhanced MR angiography was used; for assessment of hemodynamics, velocity-encoded gradient-echo sequences and cine gradient-echo sequences along the short axis of the heart were performed. Contrast-enhanced MR angiography was compared with selective digital subtraction angiography (DSA) for depiction of central thromboembolic material and visualization of the pulmonary arterial tree. Functional analysis included calculation of left and right ventricular ejection fractions and peak velocities, net forward volumes per heartbeat, and blood volume per minute in the left and right pulmonary arteries and ascending aorta. Flow measurements were compared with invasively measured mean pulmonary arterial pressure (MPAP) and pulmonary vascular resistance (PVR) measurements. Nonparametric Wilcoxon and sign tests were used for statistical analysis.


RESULTS
MR angiography revealed typical findings of CTEPH (intraluminal webs and bands, vessel cutoffs, and organized central thromboemboli) in all patients. It depicted pulmonary vessels up to the segmental level in all cases. For subsegmental arteries, DSA revealed significantly more patent vessel segments than did MR angiography (733 versus 681 segments, P <.001). MR angiography revealed technical success of surgery in 33 of 34 patients. Patients had reduced right ventricular ejection fractions and pulmonary peak velocities that significantly increased after PTE (P <.001 for both). Right ventricular ejection fraction had good correlation with PVR (r = 0.6) and MPAP (r = 0.7). The postoperative decrease in MPAP correlated well with the increase in right ventricular ejection fraction (r = 0.8). Postoperatively, there was complete reduction of a preoperatively existing bronchosystemic shunt volume in 33 of 34 patients.


CONCLUSIONS
Breath-hold MR imaging techniques enable morphologic and semiquantitative functional assessment of patients with CTEPH.
Kreitner
Karl-Friedrich Jakob
KF
Department of Radiology , Johannes Gutenberg-University Mainz, Germany. kreitner@radiologie.klinik.uni-mainz.de
Ley
Sebastian
S
Kauczor
Hans-Ulrich
HU
Mayer
Eckhard
E
Kramm
Thorsten
T
Pitton
Michael Bernhard
MB
Krummenauer
Frank
F
Thelen
Manfred
M
D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D001783:Blood Flow Velocity / Q000502:physiology; D002908:Chronic Disease; D003287:Contrast Media; D004691:Endarterectomy; D005260:Female; D005500:Follow-Up Studies; D019786:Gadolinium DTPA; D006346:Heart Septum / Q000473:pathology / Q000503:physiopathology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000175:diagnosis* / Q000503:physiopathology; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000473:pathology / Q000503:physiopathology; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D012680:Sensitivity and Specificity; D017131:Thrombectomy; D016277:Ventricular Function, Left / Q000502:physiology; D016278:Ventricular Function, Right / Q000502:physiology
D003287:Contrast Media; D019786:Gadolinium DTPA