University of Pennsylvania

Trustees of the University of Penna.

David A Roberts

John S Leigh

Mitchell D Schnall

James E Baumgardner

Rahim R Rizi

David Lipson

Erik K Insko

The present invention offers novel equilibration methods for very high resolution, three-dimensional imaging of imaging of lung compliance and distribution of functional residual capacity (FRC) in the lung using hyperpolarized helium-3 (He) gas (HHe), and collecting local magnetic resonance image data therefrom. Using the present methods permits many functions that have been performed on a regional level for the whole lung using non-polarized helium, to be calculated for the first time from the local MRI measurements of local HHe, such as measuring volume or compliance.

Equilibration method for high resolution imaging of lung compliance and distribution of functional residual capacity

The present invention comprises imaging and quantitative measurement of lung ventilation, particularly in a human lung. Methods for quantitative imaging of lung ventilation, and the further provided systems and algorithmic tools therefore, comprise three primary components: the combined MRI ventilation/perfusion (V/Q) imaging techniques using hyperpolarized helium-3 (He) gas (HHe); the three-dimensional quantitative imaging of absolute lung perfusion (Q) and collection of local magnetic resonance image data therefrom to produce an absolute lung perfusion image data; and the algorithmic co-registration of the two image data sets, (HP-He MRI image of V/Q and MR imaging of quantitative perfusion (Q) in the lung). From the data acquired in the combined data sets and their spatial co-registration, absolute ventilation (V) is computed.

Quantitative pulmonary imaging

A subtractive time of flight technique for MR angiography and quantitative blood flow measurement. Proton spins of water in the arterial supply to a tissue or organ are inverted in a steady-state fashion by applying constant amplitude off-resonance radio frequency pulses in the presence of a constant linear magnetic field gradient to effect adiabatic fast passage transport-induced inversion of spins which move in the direction of the gradient. An angiogram is formed by subtracting an image acquired with the arterial inversion pulse from a control image acquired with no arterial inversion. By inverting the spins in a steady-state manner, no cardiac gating is necessary for imaging organs. However, cardiac gating is desirable when imaging the heart so that spins of blood passing through the coronary arteries can be inverted during systole, when most of the blood is in the left ventricle, and imaged at end diastole, when most of the blood is in the coronary arteries. A coronary angiogram is then formed by subtracting images acquired with and without the inversion pulse. Also, by applying several inverting and imaging pulses during a cardiac cycle in accordance with the technique of the invention, a characteristic banding pattern may be formed in the fluid whereby each band corresponds to a population of spins that experienced inversion due to a single RF pulse. Since the width of the inversion band is proportional to the duration of the RF pulse and the velocity of the spin, measurement of the thickness of the inverted and uninverted bands allows for calculation of flow velocity. By gating such a pulse sequence to the cardiac cycle, time resolved in vivo velocity measurements may be made.

Quantitative blood flow measurement using steady-state transport-induced

MR angiography using steady-state transport-induced adiabatic fast

A new geometry for a radio frequency coil design in which longitudinal conductors of the coil lie on two parallel planes. The currents in the conductors of one plane run in the opposite direction to those of the other plane. For the case of discrete conductors, field maps illustrate that the homogeneity and sensitivity of the biplanar design are superior to that of a saddle coil, and when the design is optimized, the homogeneity is almost as good as that for comparable discrete cosine or birdcage coil designs. The measured B1 map of an optimized, single-tuned biplanar coil in accordance with the invention thus compares favorably to that of an equivalent discrete cosine coil and demonstrates excellent homogeneity in the central region of the coil. However, the biplanar RF coils of the invention are advantageous in that the cost of the coils may be substantially reduced by reducing the number of conductors, in that the coil may be easily accessed on one of its sides as well as at both ends, and in that increased sensitivity is possible since the biplanar coils may be placed closer to the objects under investigation. This makes the coil of the present invention highly desirable for certain applications such as breast, shoulder, knee, wrist, neck and cardiac imaging.

Growing community of inventors

Drexel Hill, PA, United States of America

David A Roberts