Detection of Occult Primary Tumors in Patients with Cervical Metastases of Unknown Primary Tumors: Comparison of Three-Dimensional THRIVE MR Techniques with Two-Dimensional Spin-Echo MR or Contrast-Enhanced CT Imaging

Abstract

Objective: We evaluated and compared the utility of postcontrast three-dimensional (3D) T1-weighted high resolution isotropic volume examination (THRIVE), spin-echo (SE) T1-weighted MR, and contrast-enhanced CT imaging for detecting occult primary tumors in patients with cervical lymph node metastases. Materials and Methods: Seventy-three consecutive patients with tumors that went undetected during endoscopic or physical examinations underwent preoperative contrast-enhanced CT and MR imaging (SE and 3D THRIVE) after gadolinium injection. Guided biopsy or surgery results served as reference standards. The diagnostic performances of the imaging techniques were compared with McNemar’s tests. Results: Primary tumors were identified in 59 (80.8%) of the 73 patients after surgery. Of these, 36 were found in the palatine tonsil, 11 in the base of the tongue, seven in the nasopharynx, and five in the pyriform sinus. The sensitivity (72.9%) and accuracy (71.2%) of 3D THRIVE for detecting primary tumors were higher than were those of SE T1-weighted MR (49.2% and 53.4%, P ≤ 0.002) or CT (36.4% and 46.4%, P ≤ 0.001). The specificities of these techniques did not differ. The diagnostic performance of 3D THRIVE (area under the curve [AUC] = 0.681) for detecting tumors did not differ from that of SE T1-weighted MR or CT (AUC = 0.671 and 0.608, P > 0.05). Conclusion: 3D THRIVE was more sensitive at detecting primary tumors than was SE T1-weighted MR or CT imaging in patients with cervical metastases of unknown primary tumors; this sequence may improve biopsy and therapeutic planning in these patients.