The Impact of Data Management on the Achievable Dose and Efficiency of Computed Tomography During the COVID-19 Era: A Facility-Based Ambispective Study

Figures & data

Table 1 Descriptive Statistics of the Study Participants

	Pre-Implementation [N=2207] Mean (±SD)	Post-Implementation [N=2461] Mean (±SD)	P-value
DLP (mGy.cm)	623 (579)	618 (566)	0.774
CTDIvol (mGy)	26.3 (36.6)	27.7 (36.5)	0.195
SSDE (mGy)	30.7 (31.5)	33.6 (32.8)	0.003
Patient age (years)	46.7 (18.0)	45.7 (17.4)	0.054
Sex			0.109
Female	993 (45.0%)	1166 (47.5%)
Male	1214 (55.0%)	1295 (52.6%)

Notes: Data are summarized using counts and percentages for categorical variables and continuous variables were summarized using mean (±SD). Analysis was performed using unpaired t-test for mean (±SD).

Abbreviations: N, number of patients; DLP, dose-length product; CTDIvol, volume computed tomography dose index; SSDE, size-specific dose estimate; SD, standard deviation.

Table 2 Number of CT Examinations Before and After Implementing of Data Management Software (Stratified by Body Region)

	Pre-Implementation n=2996	Post-Implementation n=3423	P value
Neck	88 (2.94%)	94 (2.75%)	0.7
Chest	217 (7.24%)	218 (6.37%)	0.18
Chest/abdomen/pelvis	55 (1.84%)	67 (1.96%)	0.972
Abdomen/pelvis	175 (5.84%)	578 (16.9%)	< 0.001
Head	1051 (35.1%)	1071 (31.3%)	0.001
Sinuses	110 (3.67%)	152 (4.44%)	0.136
Abdomen	616 (20.6%)	256 (7.48%)	< 0.001
Head/C-spine	86 (2.87%)	97 (2.83%)	0.99
C-spine	93 (3.10%)	70 (2.04%)	0.009
Temporal bone	9 (0.30%)	55 (1.61%)	<0.001
Pelvis	103 (3.44%)	71 (2.07%)	0.001
Spine	77 (2.57%)	70 (2.04%)	0.187
Head/neck	91 (3.04%)	216 (6.31%)	<0.001
Arm	27 (0.90%)	36 (1.05%)	0.629
Maxillofacial region	46 (1.54%)	86 (2.51%)	0.008
Chest/abdomen	14 (0.47%)	32 (0.93%)	0.039
Orbits	6 (0.20%)	13 (0.38%)	0.275
Leg	30 (1.00%)	43 (1.26%)	0.399
Heart	20 (0.67%)	36 (1.05%)	0.129
L-spine	34 (1.13%)	39 (1.14%)	1
Colon	29 (0.97%)	86 (2.51%)	<0.001
Head/chest	7 (0.23%)	9 (0.26%)	1
T-spine	12 (0.40%)	24 (0.70%)	0.149

Notes: Data are summarized using counts and percentages. Analysis was performed using the Chi-square test of independence.

Abbreviations: C-spine, cervical spine; L-Spine, lumbar spine; T-spine, thoracic spine; n, number of examinations; CT, computed tomography.

Figure 1 Comparison of overall computed tomographic exposure parameters between pre- and post-The introduction of rectifying measures. SSDE (A), CTDI (B), and DLP (C). Lines represent the average.

Table 3 Radiation Exposure Indices by Imaged Body Region

Body Region	SSD					DLP					CTDI
	N1	N2	M1	M2	P	N1	N2	M1	M2	P	N1	N2	M1	M2	P
Abdomen	616	256	15.70	13.86	0.00	616	256	530.91	464.08	0.00	616	256	10.86	10.16	0.12
Abdomen/pelvis	175	578	16.94	14.35	0.00	175	578	532.26	471.11	0.03	175	578	11.05	10.24	0.14
Arm	27	36	12.75	13.75	0.69	27	36	173.41	185.04	0.78	27	36	7.54	8.47	0.55
C-spine	93	70	27.85	17.30	0.00	93	70	609.23	468.39	0.00	93	70	18.93	11.09	0.00
Chest	217	218	13.03	9.72	0.00	217	218	340.85	256.17	0.00	217	218	9.27	7.08	0.00
Chest/abdomen	14	32	11.30	10.73	0.75	14	32	389.81	269.63	0.10	14	32	9.03	7.09	0.13
Chest/abdomen/pelvis	55	67	15.70	13.15	0.04	55	67	397.47	374.37	0.65	55	67	10.21	8.80	0.09
Colon	29	86	14.62	16.14	0.35	29	86	559.62	541.76	0.84	29	86	12.26	11.69	0.72
Head	1051	1071	42.51	54.48	0.00	1051	1071	777.89	878.47	0.00	1051	1071	39.16	46.06	0.00
Head/C-spine	86	97	38.38	35.40	0.19	86	97	704.53	567.05	0.00	86	97	33.20	30.27	0.31
Head/chest	7	9	22.97	23.32	0.98	7	9	684.16	769.36	0.61	7	9	31.46	38.32	0.52
Head/neck	91	216	26.05	19.71	0.01	91	216	618.00	480.36	0.00	91	216	26.91	17.01	0.00
Heart	20	36	7.83	9.53	0.31	20	36	423.83	259.87	0.01	20	36	8.74	6.61	0.38
L-spine	34	39	206.00	169.16	0.30	34	39	3646.22	2793.67	0.06	34	39	230.30	188.96	0.17
Leg	30	43	11.99	9.78	0.38	30	43	223.55	283.79	0.33	30	43	5.22	5.33	0.85
Maxillofacial	46	86	26.63	29.86	0.40	46	86	594.03	599.55	0.94	46	86	28.83	25.99	0.41
Neck	88	94	23.69	20.71	0.00	88	94	389.11	349.79	0.04	88	94	14.02	12.77	0.03
Orbits	6	13	18.91	16.83	0.81	6	13	318.92	229.77	0.46	5	10	12.77	11.50	0.07
Pelvis	103	71	14.07	14.38	0.83	103	71	488.17	481.06	0.86	103	71	10.90	10.18	0.49
Sinuses	110	152	7.79	7.93	0.71	110	152	113.74	99.49	0.01	110	152	7.44	7.13	0.15
Spine	77	70	24.42	23.94	0.76	77	70	494.69	503.52	0.83	77	70	16.12	15.35	0.48
T-Spine	12	24	22.01	27.58	0.56	12	24	551.02	741.99	0.36	12	24	15.36	23.14	0.54
Temporal bone	9	55	19.79	19.43	0.96	9	55	388.89	302.87	0.18	9	55	17.04	19.07	0.57

Note: These counts represent our departmental diagnostic reference levels for imaged body region.

Abbreviations: DLP, dose-length product (mGy.cm); CTDI, CT dose index (mGy); SSDE (mGy), size-specific dose estimate; C-spine, cervical spine; L-Spine, lumbar spine; T-spine, thoracic spine; N1, number of data points (ie, examinations) in the pre- implementation period; N2, number of data points (ie, examinations) in the post- implementation period; M1, average exposure in the pre-implementation period; M2, average exposure in the post-implementation period.

Figure 2 CT indices pre- and post-implementation of corrective measures based on imaged body region. SSDE (A), CTDI (B), and DLP (C). Overlapping bars from both time points indicate the difference in exposure between the two time points.

Abbreviations: SSDE, size-specific dose estimate; CTDI, computed tomography dose index; DLP, dose-length product; CT, computed tomography.

Figure 3 CT indices pre- and post-implementation of corrective measures based on imaging protocol. SSDE (A), CTDI (B), and DLP (C) (only protocols that were performed more than 10 times were included). Overlapping bars from both time points indicate the difference in exposure between the two time points.

Abbreviations: SSDE, size-specific dose estimate; CTDI, computed tomography dose index; DLP, dose-length product; CT, computed tomography.

Figure 4 Exposure parameters (ie, DLP (A) and CTDI (B)) used in our radiology department compared to national.^7,10 and international used parameters; from Ireland,¹¹ United Kingdom,¹² United States (American College of Radiology (ACR)),³ and European countries.^3,13.

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