title: In vivo visualization of mesoscopic anatomy of healthy and pathological lymph nodes using 7T MRI: a feasibility study.
abstract: OBJECTIVE
  To evaluate whether inguinal lymph nodes (LNs) may be visualized in vivo using 7T magnetic resonance imaging (MRI) at high spatial resolution.
  
  
  METHODS
  Twelve healthy controls and six patients with LN metastasis of melanoma were included. Examinations were performed using a 7T MRI and a transmit/receive loop coil. The protocol included a B0 -map, B1 -map, and T1 -weighted-3D-fast low-angle shot (FLASH), T1 w-Dixon-volumetric interpolated breath-hold examination (VIBE) and T2 w sequences lasting 34.4 ± 0.5 minutes. Signal- and contrast-to-noise of LNs, artery, muscle, and fat were quantified in controls. Metastatic features of LNs (hypervascularization, lymph vessels, fat hilus sign, tumor bulk, number of metastases, and size) were classified in patients.
  
  
  RESULTS
  Mesoscopic LN architecture such as central blood vessels and peripheral lymph vessels were observed in healthy controls with 0.5 mm(3) isotropic resolution for T1 w and 0.2 × 0.2 × 2 mm(3) for T2 w sequences. Mean signal-to-noise using 3D FLASH, Dixon VIBE and T2 TSE of healthy LN (27.2 ± 7.5, 35.3 ± 11.9, 31.7 ± 11.1), muscle (17.6 ± 4.6, 31.5 ± 9.3, 7.3 ± 5.4), artery (37.7 ± 5.9, 42.7 ± 19.7, 3.7 ± 3.9), and saturated fat (3.7 ± 0.9, 5.4 ± 1.9, 9.3 ± 5.2) and mean contrast-to-noise LN/fat (24.4 ± 6.7, 39.6 ± 11.1, 23.3 ± 6.1) were adequate. In patients, multiple signs of metastasis could be clearly visualized.
  
  
  CONCLUSIONS
  We present a protocol with which inguinal LNs and their mesoscopic anatomy may be visualized in vivo using 7T MRI.
authors: Section Quantitative Imaging Based Disease Characterization, Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors: Martin T
authors: MT
authors: Freitag
authors: Mathies
authors: M
authors: Breithaupt
authors: Moritz
authors: M
authors: Berger
authors: Reiner
authors: R
authors: Umathum
authors: Armin M
authors: AM
authors: Nagel
authors: Jessica
authors: J
authors: Hassel
authors: Mark E
authors: ME
authors: Ladd
authors: Heinz-Peter
authors: HP
authors: Schlemmer
authors: Wolfhard
authors: W
authors: Semmler
authors: Bram
authors: B
authors: Stieltjes
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008545:Melanoma / Q000473:pathology* / Q000556:secondary*; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: 7T; Lymph node; loop coil; melanoma; metastasis; neoangeogenesis