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Posterior pituitary bright spot

Dr Henry Knipe et al.

The posterior pituitary bright spot is an MRI feature of the normal pituitary gland wherein the posterior pituitary appears bright on non-contrast T1 weighted images. 

The posterior pituitary bright spot, having intrinsically high signal on T1 weighted images is believed to be from the storage of vasopressin, which has a T1-shortening effect 2. The hormone is synthesized in the hypothalamus and carried down the axons that form the stalk to the posterior pituitary bound to a vasopressin-neurophysin II-copeptin complex, a macroproteic structure that shortens T1 signal 4

It is important to note that a posterior pituitary bright spot is not identified in all patients, but rather somewhere between 50-100% 1,2

Additionally, in individuals with compression or interruption of the stalk the aforementioned downward transport can be halted and brightness can be seen above the compression/interruption. This should not be mistaken for an ectopic posterior pituitary 4

  • oval/round high T1 signal, best seen on sagittal images in the posterior aspect of the pituitary fossa
  • normal measurements (decreasing size with age) 1,2
    • long axis: 1.2-8.5 mm
    • short axis: 0.4-4.4 mm

The absence of posterior pituitary bright spot should prompt the consideration of the following (noting it may be absent in normal patients): 

Article information

rID: 38816
Section: Signs
Synonyms or Alternate Spellings:
  • Posterior pituitary bright spot (PPBS)
  • Pituitary hyperintense spot

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Cases and figures

  • Case 1: normal
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  • Case 2: normal
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  • Case 3: normal
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  • Case 4: ectopic posterior pituitary
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  • Case 5: absent in diabetes insipidus
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