Morphology, Volume, and Density Characteristics of the Parotid Glands before and after Chemoradiation Therapy in Patients with Head and Neck Tumors

Table 2

Statistic measures of pre- and post-RT volume and density, variation, and percentage of variation and time comparison (Student’s t-test).

Variable	Time	N	Mean	SD	Min	Median	Max	value
Total volume	Pre-RT	49	58819	18125	26127	56879	104603	<0.0001
	Post-RT	49	45695	13844	22847	47039	81123
	Variation	49	−13124	11576	−45630	−9675	9845
	Variation %	49	−20.5	16.2	−60.2	−19.2	21.7
Right parotid volume	Pre-RT	49	29274	9499	11366	28727	55220	<0.0001
	Post-RT	49	22465	6687	11476	22358	39003
	Variation	49	−6809	5871	−21744	−5539	6121
	Variation %	49	−21.0	16.4	−59.3	−19.3	28.5
Left parotid volume	Pre-RT	49	28477	8923	14445	28049	49541	<0.0001
	Post-RT	49	23159	7251	11304	23183	42119
	Variation	49	−6318	6245	−23883	−4488	6033
	Variation %	49	−19.8	−17.4	−61.1	−18.6	21.1
Right parotid density	Pre-RT	44	59	22	11	60	121	0.0198
	Post-RT	44	67	19	27	67	109
	Variation	44	7	20	−45	6	50
	Variation %	44	30.0	79.5	−48.5	9.7	455.7
Left parotid density	Pre-RT	44	59	21	13	59	102	0.0079
	Post-RT	44	67	21	17	66	103
	Variation	44	8	19	−48	7	46
	Variation %	44	24.9	62.0	−47.3	9.8	350.7

RT: radiation therapy; N: sample size; SD: standard variation; min: minimum; max: maximum. Regarding density variables, 5 patients were disregarded for being considered outliers. Volume (mm³).