title: Increased signal intensity at the proximal patellar tendon: correlation between MR imaging and histology in eight cadavers and clinical MR imaging studies.
abstract: OBJECTIVE
  We set out to investigate the cause of persistently increased signal intensity (SI) in the posterior portion of the proximal patellar tendon (pPT) on T1-weighted images (T1WI).
  
  
  METHODS
  MR imaging was performed in eight cadavers, followed by gross histological examination. In addition, 84 patients without trauma history or anterior knee pain were included to compare the SI of the PTs. The patients were divided according to their age, sex, and Kellgren-Lawrence (KL) grades. The length and thickness of the increased SI portion in the pPT and whole PT (wPT) on T1WI were recorded.
  
  
  RESULTS
  Histological specimens demonstrated that the adipose tissue, vessels, and perivascular connective tissue invaginated into the posterior portion of the pPT. This histological anatomy corresponded to the pPT signal change on MR imaging. There was linear and interdigitating increased SI of the pPT in all of the 84 patients (100%). There were no differences in the lengths and thicknesses of the increased SI portion of pPTs and wPTs according to age, sex, and KL grade (all p > 0.05).
  
  
  CONCLUSIONS
  The increased SI of the pPT on T1WI and fluid-sensitive MR images results from invaginating fat, vessels, and perivascular connective tissue. It is not pathological, but a normal and common finding.
  
  
  CONCLUSIONS
  • Increased linear/interdigitated SIs of the pPT is a normal and common finding. • Invaginated adipose tissue, vessels, and connective tissue could contribute to increased SI. • The fibrocartilage has a minimal role in increased SI of the pPT. • Age, sex, and KL grade do not significantly influence the increased SI. • Knowledge of this increased SI should help clinicians to avoid unnecessary treatment.
authors: Department of Radiology, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, 149 Sangil-dong, Gangdong-gu, Seoul, 134-727, Korea.
authors: Seong Jong
authors: SJ
authors: Yun
authors: Wook
authors: W
authors: Jin
authors: Yong-Koo
authors: YK
authors: Park
authors: Gou Young
authors: GY
authors: Kim
authors: So Hee
authors: SH
authors: Yoon
authors: So Young
authors: SY
authors: Park
authors: Jung Eun
authors: JE
authors: Lee
authors: Ji Seon
authors: JS
authors: Park
authors: Kyung Nam
authors: KN
authors: Ryu
mesh_terms: D000273:Adipose Tissue / Q000473:pathology; D000368:Aged; D000369:Aged, 80 and over; D018771:Arthralgia / Q000473:pathology; D002102:Cadaver; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D017847:Patellar Ligament / Q000473:pathology*; D012189:Retrospective Studies