Diagnostic imaging catheter

A diagnostic imaging method comprising:

• inserting a sheath of a diagnostic imaging catheter into a living body;
• and
• rotating a drive shaft of the diagnostic imaging catheter in the sheath to rotate an imaging core portion of the diagnostic imaging catheter that is attached to the drive shaft in the sheath, wherein
• the imaging core portion includes:
• a transmission and reception member capable of transmitting and receiving a signal;
• and
• a housing holding the transmission and reception member,
• a side surface of the housing that faces a radial direction of the sheath includes an inclined portion that is inclined, up to a distal end of the housing, to approach a central axis line of the drive shaft from a proximal side to a distal side of the inclined portion, and
• the inclined portion extends from a proximal side of a distal end of the transmission and reception member to a distal side of the distal end of the transmission and reception member.