A hybrid breath hold and continued respiration-triggered technique for time-resolved 3D MRI perfusion studies in lung cancer.
OBJECTIVE
Assessment of lung cancer perfusion is impaired by respiratory motion. Imaging times for contrast agent wash-out studies often exceed breath hold capabilities, and respiration triggering reduces temporal resolution. Temporally resolved volume acquisition of entire tumors is required to assess heterogeneity. Therefore, we developed and evaluated an MR measurement technique that exceeds a single breath hold, and provides a variable temporal resolution during acquisition while suspending breath-dependent motion.


METHODS
20 patients with suspected lung cancer were subjected to perfusion studies using a spoiled 3D gradient echo sequence after bolus injection of 0.07 mmol/kg body weight of Gd-DTPA. 10 acquisitions in expiratory breath hold were followed by 50 navigator-triggered acquisitions under free breathing. Post-processing allowed for co-registration of the 3D data sets. An ROI-based visualization of the signal-time curves was performed.


RESULTS
In all cases motion-suspended, time-resolved volume data sets (40 x 33 x 10 cm(3), voxel size: 2.1 x 2.1 x 5.0 mm(3)) were generated with a variable, initially high temporal resolution (2.25 sec) that was synchronized with the breath pattern and covered up to 8 1/2 min. In 7 / 20 cases a remaining offset could be reduced by rigid co-registration. The tumors showed fast wash-in, followed by rapid signal decay (8 / 20) or a plateau.


CONCLUSIONS
The feasibility of a perfusion study with hybrid breath hold and navigator-triggered time-resolved 3D MRI which combines high initial temporal resolution during breath hold with a long wash-out period under free breathing was demonstrated.
Hintze
C
C
Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg. christian.hintze@dkfz-heidelberg.de
Stemmer
A
A
Bock
M
M
Kuder
T A
TA
Risse
F
F
Dinkel
J
J
Prüm
H
H
Puderbach
M
M
Fink
C
C
Biederer
J
J
Kauczor
H-U
HU
D000368:Aged; D016477:Artifacts; D001783:Blood Flow Velocity / Q000502:physiology; D002289:Carcinoma, Non-Small-Cell Lung / Q000098:blood supply / Q000175:diagnosis; D018288:Carcinoma, Small Cell / Q000098:blood supply / Q000175:diagnosis; D003287:Contrast Media / Q000008:administration & dosage; D005240:Feasibility Studies; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008175:Lung Neoplasms / Q000098:blood supply* / Q000175:diagnosis*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009929:Organ Size / Q000502:physiology; D015656:Respiratory Mechanics / Q000502:physiology*; D012984:Software
D003287:Contrast Media; D019786:Gadolinium DTPA