Article Figures & Data
Figures
- Fig 1.
False-negative findings for skull base invasion by conventional CT images alone in a 74-year-old woman with nasopharyngeal carcinoma. A, Axial contrast-enhanced CCT image (soft-tissue window) shows nasopharyngeal tumor (T) spread into the lateral soft tissue around the foramen lacerum (arrowheads). CCT images at the skull base level (B, soft-tissue window; C, bone window) show no destruction of the skull base at the clivus (arrowhead). D, Bone subtraction iodine image shows remarkable skull base invasion into the bone marrow space such as the clivus, petrous apex, and sphenoid bone (arrowheads) with intracranial extension at the jugular foramen (arrow). A corresponding slice on a T1-weighted image (E) and fat-suppressed T1-weighted image after gadolinium administration (F) show tumor invading the clivus (arrowheads) and spread into the jugular foramen (arrow).
- Fig 2.
False-positive findings at the base of the left pterygoid process on conventional CT images alone in a 63-year-old woman with nasopharyngeal carcinoma. Coronal contrast-enhanced CCT images (A, soft-tissue window; B, bone window) show nasopharyngeal tumor (T) and bone sclerosis at the left base of the pterygoid process (arrow). The case was given a score of 3 based on CCT images alone. Bone subtraction iodine image (C) and color fusion image (D) clearly show no enhancement in the sclerotic area (arrow). E, A corresponding slice on the T1-weighted image shows low signal intensity due to sclerosis (arrow). F, Fat-suppressed T1-weighted images after gadolinium administration show contrast enhancement of the tumor mass and poor enhancement of the pterygoid process (arrow). This was considered a case of clinical T2 category disease without skull base invasion and was treated by chemoradiotherapy.
- Fig 3.
Receiver operating characteristic curves and corresponding areas under the curve for the prediction of skull base invasion. The AUC for CCT-plus-BSI imaging was significantly larger (AUC = 0.98 [P < .001]) than that for CCT imaging alone (AUC = 0.90).
Tables
Characteristics No. % Age (yr) Mean 60 Range 18–79 Sex Female 16 36.0% Male 28 64.0% Histopathology Nonkeratinizing carcinoma 29 65.9% Differentiated 8 Undifferentiated 19 Unknown 2 Keratinizing carcinoma 8 18.2% Unknown 7 15.9% TNM (7th AJCC) T1 8 18.2% T2 10 22.7% T3 4 9.1% T4 22 50.0% N0 3 6.8% N1 16 36.4% N2 13 29.5% N3a 1 2.3% N3b 11 25.0% M0 41 93.2% M1 3 6.8% Subsite Posterior superior 12 27.3% Lateral wall 32 72.7% Note:—TNM indicates tumor, node, metastasis tumor stage; AJCC, American Joint Committee on Cancer.
- Table 2:
Comparison between CCT images alone and CCT-plus-BSI images of skull base invasiona
Parameter TPb TNb FNb FPb Sensitivity (%) P Value Specificity (%) P Value PPV (%) NPV (%) All sites CCT alone 66 155 18 25 79 (68–87) .016c 86 (80–90) .010c 73 90 CCT-plus-BSI 78 172 6 8 93 (85–97) 96 (91–98) 91 97 Sphenoid body CCT alone 18 14 4 8 82 (60–95) .625 64 (41–83) .039d 69 78 CCT-plus-BSI 20 21 2 1 91 (71–99) 95 (77–100) 95 91 Clivus CCT alone 11 22 9 2 55 (32–77) .031d 92 (73–99) 1.000 85 71 CCT-plus-BSI 17 22 3 2 85 (62–97) 92 (73–99) 89 88 Base of the pterygoid process CCT alone 17 60 1 10 94 (73–100) .157 86 (75–93) .012c 63 98 CCT-plus-BSI 18 68 0 2 100 (81–100) 97 (90–100) 90 100 Petrous apex CCT alone 20 59 4 5 83 (63–95) .221 92 (83–97) .306 80 94 CCT-plus-BSI 23 61 1 3 96 (79–100) 95 (87–99) 88 98 Note:—FN indicates false-negative findings; FP, false-positive findings; NPV, negative predictive value; PPV, positive predictive value; TN, true-negative findings; TP, true-positive findings.
↵a Numbers in parentheses are 95% confidence intervals.
↵b Data are numbers of findings.
↵c P < .05, according to the generalized estimating equations that accounted for the multiple observations within patients.
↵d P < .05, as determined with the McNemar test.
