Accuracy of gadofosveset-enhanced MRI for nodal staging and restaging in rectal cancer.
OBJECTIVE
To prospectively assess the accuracy of gadofosveset-enhanced magnetic resonance imaging (MRI) for nodal staging and restaging in rectal cancer.


BACKGROUND
Accurate preoperative assessment of nodal disease in rectal cancer impacts treatment management. Staging with modern imaging techniques (computed tomography, MRI and endorectal ultrasound) is insufficiently accurate for clinical decision making. This study aims to assess the accuracy of MRI using a novel lymph node magnetic resonance contrast, gadofosveset, for nodal staging and restaging in rectal cancer using a per node comparison with histology as the reference standard.


METHODS
Sixty-eight patients underwent gadofosveset-enhanced MRI at 1.5T. Twenty-six patients (primary staging group I) were treated with total mesorectal excision (with or without preoperative 5 × 5 Gy) and 42 (restaging group II) underwent a long course of chemoradiation followed by a restaging MRI and resection. Nodes were scored as benign or malignant by 2 radiologists (experienced and junior reader) first on standard MRI, then on gadofosveset-enhanced MRI. For group I the primary staging MRI was compared with histology. In group II the second, restaging MRI was compared with histology.


RESULTS
For the experienced reader, sensitivity, specificity, and area under the ROC-curve (AUC) improved from 76%, 82% and 0.84 on standard MRI to 80%, 97% and 0.96 on gadofosveset-MRI (P < 0.001). For the junior reader results improved from 69%, 85%, and 0.85 on standard MRI to 70%, 95%, and 0.93 on gadofosveset-MRI (P = 0.03). Interobserver agreement was good on both standard MRI (κ 0.73) and gadofosveset-MRI (κ 0.71).


CONCLUSIONS
This study shows high reproducibility and significantly improved accuracy compared to standard MRI for gadofosveset-enhanced MRI for nodal staging and restaging in rectal cancer.
Department of Radiology, Maastricht University Medical Center, The Netherlands.
Doenja M J
DM
Lambregts
Geerard L
GL
Beets
Monique
M
Maas
Alfons G H
AG
Kessels
Frans C H
FC
Bakers
Vincent C
VC
Cappendijk
Sanne M E
SM
Engelen
Max J
MJ
Lahaye
Adriaan P
AP
de Bruïne
Guido
G
Lammering
Tim
T
Leiner
Jan L
JL
Verwoerd
Joachim E
JE
Wildberger
Regina G H
RG
Beets-Tan
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D009942:Organometallic Compounds; D011379:Prognosis; D011446:Prospective Studies; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D012007:Rectum / Q000473:pathology / Q000601:surgery; D012680:Sensitivity and Specificity
D003287:Contrast Media; D009942:Organometallic Compounds; D005682:Gadolinium; C109932:gadofosveset trisodium