[(18)F]Flutemetamol PET imaging and cortical biopsy histopathology for fibrillar amyloid β detection in living subjects with normal pressure hydrocephalus: pooled analysis of four studies

Acta Neuropathol. 2012 Dec;124(6):833-45. doi: 10.1007/s00401-012-1051-z. Epub 2012 Oct 10.


Molecular imaging techniques developed to 'visualize' amyloid in vivo represent a major achievement in Alzheimer's disease (AD) research. This pooled analysis of four studies determined the level of association between uptake of the fibrillar amyloid β positron emission tomography (PET) imaging agent [(18)F]flutemetamol (Pittsburgh Compound B analog with a 5.5 times longer half-life to enable it to be used in the clinical setting) and neuritic plaques and fibrillar amyloid β measured by pathologic staining of cortical region biopsy samples. Fifty-two patients with suspected normal pressure hydrocephalus underwent prospective (n = 30) or retrospective (n = 22) [(18)F]flutemetamol PET imaging for detection of cerebral cortical fibrillar amyloid β and cortical brain biopsy during intracranial pressure measurement or ventriculo-peritoneal shunting. [(18)F]Flutemetamol uptake was quantified using standardized uptake value ratio (SUVR) with cerebellar cortex as the reference region. Tissue fibrillar amyloid β was evaluated using immunohistochemical monoclonal antibody 4G8 and histochemical agents Thioflavin S and Bielschowsky silver stain, and an overall pathology result based on all available immunohistochemical and histochemical results. Biopsy site and contralateral [(18)F]flutemetamol SUVRs were significantly associated with neuritic plaque burden assessed with Bielschowsky silver stain (r (spearman's) = 0.61, p = 0.0001 for both), as was the composite SUVR with biopsy pathology (r (spearman's) = 0.74, p < 0.0001). SUVR and immunohistochemical results with 4G8 for detecting fibrillar amyloid β were similar. Blinded image evaluation showed strong agreement between readers (κ = 0.86). Overall sensitivity and specificity by majority read were 93 and 100 %. Noninvasive in vivo [(18)F]flutemetamol PET imaging demonstrates strong concordance with histopathology for brain fibrillar amyloid β, supporting its promise as a tool to assist physicians with earlier detection of the disease process and making diagnostic decisions about concomitant AD and other diseases associated with brain amyloidosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alzheimer Disease / complications
  • Alzheimer Disease / diagnostic imaging*
  • Alzheimer Disease / metabolism
  • Alzheimer Disease / pathology
  • Amyloid / metabolism*
  • Amyloid beta-Peptides / metabolism*
  • Aniline Compounds
  • Benzothiazoles
  • Biopsy / methods
  • Brain / diagnostic imaging*
  • Brain / pathology
  • Female
  • Humans
  • Hydrocephalus, Normal Pressure / complications
  • Hydrocephalus, Normal Pressure / diagnostic imaging*
  • Hydrocephalus, Normal Pressure / pathology
  • Male
  • Middle Aged
  • Plaque, Amyloid / pathology
  • Positron-Emission Tomography
  • Prospective Studies
  • Retrospective Studies


  • Amyloid
  • Amyloid beta-Peptides
  • Aniline Compounds
  • Benzothiazoles
  • flutemetamol