Characterization of tumors of jaw: Additive value of contrast enhancement and dual-energy computed tomography

Table 1 Spectrum of lesions in histopathology

Final diagnosis	Number of lesions	Percentage (%)
Ameloblastomas	20	35
Central giant cell granuloma	11	19
Odontogenic keratocyst	6	10
Ossifying fibroma	5	8
Salivary gland tumors	2	4
Malignancy	3	5
Chondromyxoid fibroma	1	2
Non-tumorous	5	9
Sclerotic lesions	2	4
Ameloblastic fibroma	1	2
Odontogenic myxoma	1	2
Total	57	100

Table 2 Comparison of morphological characteristics between ameloblastoma and non-ameloblastoma groups

Variable	Ameloblastoma (n = 20)	Non-ameloblastoma (n = 37)	P value
Volume, cm3	73.6 (7.6–1014)	39.12 (0.6–1296)	< 0.05
Cystic/necrotic areas	100	51	< 0.05
Cortical expansion/thinning	100	78	< 0.05
Mandibular canal involvement	60	32	< 0.05
Retromolar trigone involvement	45	18	< 0.05

Table 3 Classification of lesions based on iodine concentration (μg/mL)

Iodine concentration (μg/mL)	0-15 (low)	16-30 (moderate)	31-45 (high)	≥ 46 (extreme)
Ameloblastoma	2	11	4	1
CGCG	0	1	8	0
OKC	5	0	0	0
OF	0	3	0	0
Salivary gland tumor	1	1	0	0
Chondromyxoid fibroma	0	0	0	1
Others	4	6	2	1

All odontogenic keratocysts had a lower iodine concentration (0-15). Ameloblastomas predominantly had a moderate iodine concentration (16-30). Central giant cell granuloma predominantly had a higher iodine concentration (31-45). OKC: Odontogenic keratocysts; OF: Ossifying fibromas; CGCG: Central giant cell granuloma.

Table 4 Comparison of dual-energy computed tomography quantitative parameters between subgroups

Parameters	Amelo, mean ± SD	OKC, mean ± SD	CGCG, mean ± SD	Other JT, mean ± SD	1P value	2P value	3P value
Mean HU	122 ± 28.3	33 ± 12.4	151 ± 24.3	117 ± 37.9	0.007	< 0.001	0.616
IC	29 ± 9.3	7.2 ± 5.8	36.1 ± 6.8	24.8 ± 11.5	0.036	< 0.001	0.232
WC	1032.5 ± 13	1010 ± 11	1043 ± 11.6	1040 ± 11.4	0.036	0.044	0.056
NIC	0.35 ± 0.15	0.10 ± 0.1	0.59 ± 0.25	0.39 ± 0.24	0.011	0.007	0.501
WC (cystic)	997 ± 5.6	1020 ± 5	-	-	-	< 0.001	-

¹P value obtained on comparison between ameloblastomas and central giant cell granulomas.

²P value obtained when unilocular ameloblastomas were compared with odontogenic keratocysts.

³P value obtained when ameloblastomas were compared with other jaw tumors.

Mean HU is the mean computed tomography density expressed in Hounsfield units. IC is the Iodine concentration of solid enhancing component expressed in 100 μg/cm³. WC is the water concentration of solid enhancing component expressed in 1000 mg/cm³. NIC is the normalized iodine concentration calculated as a ratio. WC (cystic) is the water concentration of cystic component calculated only in cases of unilocular ameloblastomas and OKCs. Other jaw tumor are a subgroup of lesions excluding ameloblastoma, CGCG and OKCs. IC: Iodine concentration; WC: Water concentration; NIC: Normalized iodine concentration; OKC: Odontogenic keratocyst; JT: Jaw tumor; CGCG: Central giant cell granuloma.

Table 5 Receiver operating characteristic analysis of dual-energy computed tomography parameters between ameloblastoma and central giant cell granulomas

Variable	Cutoff value	Sensitivity, %	Specificity, %	AUC	SE
IC	32.1	81.82	65.00	0.727	0.0955
Mean HU	134	81.82	65.00	0.789	0.0832
WC	1036	72.73	50.00	0.6659	0.1
NIC	0.4	81.82	70.00	0.795	0.0970

Mean HU is the mean computed tomography density expressed in Hounsfield units. IC: Iodine concentration; WC: Water concentration; NIC: Normalized iodine concentration; AUC: The area under the receiver operating characteristic curve.

Table 6 Comparison of dual-energy computed tomography quantitative parameters based on morphology

Lytic unilocular (n = 21)	Amelo, n = 7 (mean ± SD)	OKC, n = 6 (mean ± SD)	CGCG, n = 2 (mean ± SD)	OF, n = 2 (mean ± SD)	Non-tumorous, n = 4 (mean ± SD)
Mean HU	115 ± 18.3	33 ± 12.4	135 ± 24	87 ± 17.9	67 ± 17.9
IC	28 ± 8.3	7.2 ± 5.8	32.9 ± 6.8	18.8 ± 9.5	8.8 ± 9.5
WC	1030.5 ± 12.8	1010 ± 11.3	1043 ± 11.6	1038 ± 11.4	1018 ± 11.4
NIC	0.37 ± 0.15	0.10 ± 0.1	0.72 ± 0.3	0.45 ± 0.24	0.25 ± 0.24
Lytic multilocular (n = 18)	Amelo, n = 8 (mean ± SD)	CGCG, n = 4 (mean ± SD)	SG tumors, n = 2 (mean ± SD)	Malignancy, n = 3 (mean ± SD)	Non-tumorous, n = 1 (mean ± SD)
Mean HU	123 ± 21.3	152 ± 20.4	94.2 ± 24.3	120 ± 37.9	69 ± 18.9
IC	29 ± 9.3	35.1 ± 9.8	17.85 ± 6.8	24.8 ± 11.5	10 ± 2.5
WC	1032.5 ± 12.8	1048 ± 11.3	1038 ± 11.6	1040 ± 11.4	1011 ± 11.4
NIC	0.35 ± 0.15	0.54 ± 0.19	0.18 ± 0.05	0.39 ± 0.24	0.29 ± 0.1
Mixed-sclerotic (n = 16)	Amelo, n = 5 (mean ± SD)	CGCG, n = 5 (mean ± SD)	OFs, n = 4 (mean ± SD)	CMF, n = 1 (mean ± SD)	Non-tumorous, n = 1 (mean ± SD)
Mean HU	129 ± 20.3	158 ± 20.4	143.8 ± 24.3	164 ± 37.9	77 ± 16
IC	29.5 ± 9.3	38.2 ± 9.8	31.1 ± 6.8	49.8 ± 11.5	11.8 ± 9
WC	1032.5 ± 12.8	1048 ± 11.3	1043 ± 11.6	1037 ± 11.4	1028 ± 20.4
NIC	0.35 ± 0.15	0.60 ± 0.19	0.66 ± 0.25	0.37 ± 0.24	0.19 ± 0.14

Amelo: Ameloblastoma; OKC: Odontogenic keratocysts; OF: Ossifying fibromas; CGCG: Central giant cell granuloma; SG tumors: Salivary gland tumors; IC: Iodine concentration; WC: Water concentration; NIC: Normalized iodine concentration; CMF: Chondromyxoid fibroma