Table 2. Imaging procedures performed during the study period.

	1982–85		1986–89		1990–93		1994–97
Period	No.	%	No.	%	No.	%	No.	%	P
Fibrescopy	336	96.6	412	97.4	454	97.8	474	96.3	0.4999
Thoracic-CT scana	72	20.7	177	42.0	402	86.8	472	96.3	<0.0001
Thoracic NMRb			10	2.4	12	2.6	11	2.3	0.9501
Abdominal US	321	92.8	376	90.4	425	92.6	425	89.3	0.1973
Adrenal CT scana	18	5.2	83	20.0	220	48.1	245	51.6	<0.0001
Abdominal CT scana	12	3.5	30	7.2	82	17.9	134	28.1	<0.0001
Brain CTa	33	9.6	160	38.5	313	67.7	386	80.9	<0.0001
Bone scana	171	49.4	175	42.1	212	46.4	275	57.8	<0.0001
Brain scana	67	19.4	16	3.9	0	0.0	0	0.0	<0.0001
Brain NMRa	1	0.3	3	0.7	7	1.5	10	2.1	0.0823
Mediastinoscopy	2	0.6	4	1.0	6	1.3	5	1.0	0.8181
Other	35	10.1	34	8.2	41	9.0	37	7.8	0.6643

^aLinear trend significant.

^bχ2 calculated from 1986. CT: computed tomography; US: ultrasound; NMR: nuclear magnetic resonance imaging.