title: Comparison of Standard and Quadruple-Phase Contrast Material Injection for Artifacts, Image Quality, and Radiation Dose in the Evaluation of Head and Neck Cancer Metastases.
abstract: OBJECTIVE
  To investigate opacification of head and neck vasculature during computed tomography (CT) of supraclavicular lymph nodes with a quadruple-phase contrast media and saline dual-injection protocol.
  
  
  METHODS
  This retrospective study was institutional review board approved. In 180 consecutive patients, routine head and neck CT was performed with one of two protocols: protocol A, craniocaudal scan direction with 100 mL of contrast material injected intravenously as a single bolus; or protocol B, 100 mL of contrast material injected in four phases (phases 1-2, 60 mL of contrast material and saline injected at 2.5 mL/sec; phases 3-4, 40 mL of contrast material and saline injected at 2.5 mL/sec); both protocols had a fixed scan delay of 70 seconds. Attenuation of supraclavicular arteries and veins was measured with arteriovenous contrast ratio (AVCR) and contrast-to-noise ratio (CNR). Effective dose was calculated. Data were compared with the two-sample t test. Receiver operating characteristic (ROC) and visual grading characteristic analyses were performed.
  
  
  RESULTS
  Arterial attenuation was up to 20% higher (P < .05) after protocol B (mean ± standard deviation, 234.5 HU ± 33.2) than protocol A (160.0 HU ± 29.5). Venous system attenuation was significantly lower in protocol B (164.0 HU ± 17.0) than in protocol A (664.0 HU ± 12.0), with up to a 75% reduction (P < .0001). Protocol B generated significant (P < .0001) improvements in AVCR at multiple anatomic sites. At all anatomic levels, mean CNR with protocol B (34.4 HU ± 9.0) was significantly higher than that with protocol A (14.5 HU ± 14.0) (P < .0313). Effective dose was significantly reduced with protocol B (2.6 mSv ± 0.4 vs 3.2 mSv ± 0.8 with protocol A; P < .0041). ROC analysis demonstrated significantly higher area under the ROC curve for protocol B (P < .0022), with interreader agreement increasing from poor to excellent in lymph node visualization.
  
  
  CONCLUSIONS
  Significant improvement in lymph node visualization at the cervicothoracic junction is achieved with a quadruple-phase contrast media injection protocol.
authors.affiliation: From the Department of Diagnostic Radiology, American University of Beirut Medical Center, PO Box 11-0236, Riad El Solh, Beirut 1107 2020, Lebanon (C.S., F.E.); Department of Radiology, Campbelltown Public Hospital, Campbelltown, NSW, Australia (A.M.); Discipline of Medical Radiation Sciences, University of Sydney, Lidcombe, NSW, Australia (P.C.B.); and Department of Diagnostic Radiology, Johns Hopkins Hospital, Baltimore, Md (D.Y.).
authors.forename: Charbel
authors.initials: C
authors.lastname: Saade
authors.affiliation: From the Department of Diagnostic Radiology, American University of Beirut Medical Center, PO Box 11-0236, Riad El Solh, Beirut 1107 2020, Lebanon (C.S., F.E.); Department of Radiology, Campbelltown Public Hospital, Campbelltown, NSW, Australia (A.M.); Discipline of Medical Radiation Sciences, University of Sydney, Lidcombe, NSW, Australia (P.C.B.); and Department of Diagnostic Radiology, Johns Hopkins Hospital, Baltimore, Md (D.Y.).
authors.forename: Fadi
authors.initials: F
authors.lastname: El-Merhi
authors.affiliation: From the Department of Diagnostic Radiology, American University of Beirut Medical Center, PO Box 11-0236, Riad El Solh, Beirut 1107 2020, Lebanon (C.S., F.E.); Department of Radiology, Campbelltown Public Hospital, Campbelltown, NSW, Australia (A.M.); Discipline of Medical Radiation Sciences, University of Sydney, Lidcombe, NSW, Australia (P.C.B.); and Department of Diagnostic Radiology, Johns Hopkins Hospital, Baltimore, Md (D.Y.).
authors.forename: Ahmad
authors.initials: A
authors.lastname: Mayat
authors.affiliation: From the Department of Diagnostic Radiology, American University of Beirut Medical Center, PO Box 11-0236, Riad El Solh, Beirut 1107 2020, Lebanon (C.S., F.E.); Department of Radiology, Campbelltown Public Hospital, Campbelltown, NSW, Australia (A.M.); Discipline of Medical Radiation Sciences, University of Sydney, Lidcombe, NSW, Australia (P.C.B.); and Department of Diagnostic Radiology, Johns Hopkins Hospital, Baltimore, Md (D.Y.).
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Brennan
authors.affiliation: From the Department of Diagnostic Radiology, American University of Beirut Medical Center, PO Box 11-0236, Riad El Solh, Beirut 1107 2020, Lebanon (C.S., F.E.); Department of Radiology, Campbelltown Public Hospital, Campbelltown, NSW, Australia (A.M.); Discipline of Medical Radiation Sciences, University of Sydney, Lidcombe, NSW, Australia (P.C.B.); and Department of Diagnostic Radiology, Johns Hopkins Hospital, Baltimore, Md (D.Y.).
authors.forename: David
authors.initials: D
authors.lastname: Yousem
mesh_terms: D016477:Artifacts; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging* / Q000473:pathology; D011829:Radiation Dosage; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014283:Triiodobenzoic Acids / Q000008:administration & dosage*
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; C054871:ioversol