Apparatus and method for non-invasive measurement of cardiac output

A method for non-invasively performing an examination to determine selected physical characteristics of the heart and cardiovascular system of a living subject, said method comprising the steps of:

• selecting an extremity of the subject suitable for conducting said examination;
• providing an apparatus adapted to conduct MRI analysis of selected blood vessels within said extremity, said MRI apparatus of the type having an integral housing enclosing first and second opposed permanent magnet arrangements defining an air gap there between, an access port in said housing to enable the placement of said extremity within said air gap, and means to create a magnetic field across said air gap with sufficient field strength, uniformity and resolution to perform said examination;
• providing said apparatus with side magnets and at least one shim magnet adapted to increase the strength and uniformity of said magnetic field, said shim magnet provided with at least one adjusting bolt rotatably journaled to each of said shim magnet;
• wherein adjustment of said bolt results in a change in said magnetic field such that a uniform magnetic field is provided;
• providing an array of RF coils to pulse and detect electromagnetic signals within said air gap;
• pulsing selected of said RF coils and detecting the signals produced thereby;
• rotating said adjusting bolt;
• thereby increasing the strength and uniformity of said magnetic field;
• creating an MRI image of said selected blood vessels at selected time intervals to produce information to determine said heart and cardiovascular system characteristics;
• and
• collecting and analyzing said information;
• wherein said heart and cardiovascular system characteristics are determinable accurately within a high strength uniform and high resolution magnetic field across a portion of the body.