In this retrospective clinical and radiological study of people who underwent microscopic lumbar discectomy (MLD) for herniated nucleus pulposus (HNP) (n = 88) at a single institution over a 2-year period, researchers investigated the MRI features in people with HNP that prognosticate significant clinical improvement in health-related quality of life scores (HRQoL) following MLD. Compared with those who did not meet MCID, persons who met minimal clinically important differences (MCID) following MLD had larger HNP areas and larger Hemi-HNP areas. These people were also 2.7-fold more inclined to have a gray MRI signal in comparison with a mixed or black MRI signal. When accounting for the HNP area with regard to the canal area, people who met MCID had greater Hemi-HNP canal occupation vs individuals who did not meet MCID. Thus, the results of this study imply that, in prognosticating patient-reported improvement following MLD, preoperative MRI parameters could be beneficial.