An apparatus for determining whether a blood vessel is obstructed, comprising: an interface for communication with an imaging device, wherein said imaging device comprises a transmitter and a receiver, a user interface, and a processor, wherein the processor is programmed to perform the following steps: display to the user, via the user interface, where to place the imaging device on a patient's body, instruct the imaging device to transmit radiation, receive reflected radiation from the imaging device, process the reflected radiation using machine learning to determine from the reflected radiation whether the imaging device is located correctly relative to a blood vessel of the patient, display to the user, via the user interface, if the imaging device is not located correctly and to reposition the imaging device until the imaging device is correctly located, display to the user, via the user interface, to apply pressure to the patient's blood vessel using the imaging device, instruct the imaging device to transmit further radiation, receive further reflected radiation from the imaging device, and determine from at least the further reflected radiation whether the blood vessel is obstructed. an interface for communication with an imaging device, wherein said imaging device comprises a transmitter and a receiver, a user interface, and a processor, wherein the processor is programmed to perform the following steps: display to the user, via the user interface, where to place the imaging device on a patient's body, instruct the imaging device to transmit radiation, receive reflected radiation from the imaging device, process the reflected radiation using machine learning to determine from the reflected radiation whether the imaging device is located correctly relative to a blood vessel of the patient, display to the user, via the user interface, if the imaging device is not located correctly and to reposition the imaging device until the imaging device is correctly located, display to the user, via the user interface, to apply pressure to the patient's blood vessel using the imaging device, instruct the imaging device to transmit further radiation, receive further reflected radiation from the imaging device, and determine from at least the further reflected radiation whether the blood vessel is obstructed. display to the user, via the user interface, where to place the imaging device on a patient's body, instruct the imaging device to transmit radiation, receive reflected radiation from the imaging device, process the reflected radiation using machine learning to determine from the reflected radiation whether the imaging device is located correctly relative to a blood vessel of the patient, display to the user, via the user interface, if the imaging device is not located correctly and to reposition the imaging device until the imaging device is correctly located, display to the user, via the user interface, to apply pressure to the patient's blood vessel using the imaging device, instruct the imaging device to transmit further radiation, receive further reflected radiation from the imaging device, and determine from at least the further reflected radiation whether the blood vessel is obstructed.