Magnetic resonance imaging of ventilation and perfusion in the lung

A magnetic resonance imaging system to characterize ventilation and perfusion in a lung, comprising:

• a magnetic resonance imaging machine that acquires an MR image of the lung;
• and
• a processing unit having a processor and a non-transitory computer-readable storage medium having instructions stored thereon that when executed by the processor cause the processing unit to at least:
• command the magnetic resonance imaging machine to acquire the MR image that includes MR data in each voxel of the MR image,
• process the MR data to determine a water density value and a perfusion value in at least one voxel of the MR image, wherein the water density value is used to determine an air content value,
• measure a breathing frequency of the lung;
• determine a specific ventilation value in the at least one voxel based on a time delay between an onset of a stimulus to the lung and a response detected in the at least one voxel;
• determine a ventilation-perfusion ratio value that is the product of the specific ventilation value, the air content value, the inverse of the perfusion value, and the breathing frequency;
• and
• evaluate a spatial distribution of the specific ventilation value, perfusion value, and the ventilation-perfusion ratio by computing a standard deviation of the specific ventilation value and perfusion value;
• wherein the specific ventilation value is computed by SVI*(1−density)*fB wherein SVI represents quantitative data from the MR image, (1−density) represents the air content value, and fB represents the breathing frequency value, thereby determining when the lung is diseased.

A computer program product comprising a non-transitory computer-readable storage medium having instructions stored thereon, the instructions comprising:

• code for acquiring, using a magnetic resonance imaging (MRI) machine, an MR image of a lung that includes MR data in a voxel of the MR image;
• code for determining a water density value and a perfusion value in at least one voxel of the MR image based on the MR data, wherein the water density value is used to determine an air content value;
• code for measuring a breathing frequency value;
• code for determining a specific ventilation value in the at least one voxel based on a time delay between an onset of a stimulus to the lung and a response detected in the at least one voxel;
• code for determining a ventilation-perfusion ratio value that is the product of the specific ventilation value, the air content value, the inverse of the perfusion value, and the breathing frequency value;
• and
• code for evaluating a spatial distribution of the specific ventilation value, perfusion value, and the ventilation-perfusion ratio by computing a standard deviation of the specific ventilation value and perfusion value,
• wherein the specific ventilation value is computed by SVI*(1−density)*fB wherein SVI represents quantitative data from the MR image, (1−density) represents the air content value, and fB represents the breathing frequency value, thereby determining when the lung is diseased.