The invention provides for a medical instrument (100), which comprises a magnetic resonance imaging system (106) for acquiring magnetic resonance data (170) from a subject within an imaging zone (138). The medical instrument (100) further comprises a memory (162) storing a map (174, 320) defining at least one anatomical area of relevance (322, 324) and is configured to acquire magnetic resonance data (170) using the magnetic resonance imaging system (106). A magnetic resonance image (172, 300) is reconstructed using the acquired magnetic resonance data. The reconstructed image (172, 300) is matched with the map (174, 320). The at least one anatomical area of relevance (322, 324) is identified in the reconstructed image (172, 300). The quality of the reconstructed image (172, 300) is determined based on whether the magnetic resonance image (172, 300) comprises an artefact (304) located within the at least one area of relevance (322, 324) defined by the map (174, 320). A signal indicative of the validity of the reconstructed image (172) is generated, in case no artefact (304) is determined to be located within the at least one area of relevance (322, 324) defined by the map (174, 320).
