Inter-reader agreement of interpretation of radiological course of bile duct changes between serial follow-up magnetic resonance imaging/3D magnetic resonance cholangiopancreatography of patients with primary sclerosing cholangitis

Figures & data

Table 1. Demographic and laboratory data of study population (n = 40).

	Study population	Normal range (male/female)	N
Number of patients	40	–	40
Male/Female	29/11	–	40
Age	47 (23–79)	–	40
Time from diagnosis to second MRI (years)	6.8 (1–27)	–	28
Mean time between two MRIs (months)	16 (5.5–37)	–	40
Bilirubin (μmol/l)	12	<26	38
ASAT (U/L)	41.2	<44.7/<35.9	37
ALAT (U/L)	40.6	<70.6/<44.7	37
GT (U/L)	117.6	<82.3/<76.5	37
ALP (U/L)	123.5	<117.8	38
Albumin (gr/L)	38	36–48/36–35	37
INR	1	<1.2	35
Creatinine (μmol/L)	76	<100/<90	37
Number of patients undergoing ERCP between MRIs	6	–	–
Patients undergoing ERCP within 1 year after second MRI	7	–	–

All values expressed as medians unless stated otherwise.

All values are at the time of second MRI.

ALP: alkaline phosphatase; ALAT: alanine aminotransferase; ASAT: aspartate aminotransferase; GT: glutamyl transferase; INR: international normalized ratio.

Table 2. Technical parameters of MRI sequences used in the study.

Sequence	Plane	Thickness (mm)	TE (ms)	TR (ms)	Scan time	Breathing technique
T2-w HASTE	Axial	4	124	1500	1–2 min	PACE
T2-w HASTE	Coronal	4	76	1080	1–2 min	PACE
T2-w 3D SPACE MRCP	Axial	2.5	685	4536	4–6 min	PACE
T2-w 3D SPACE MRCP	Coronal	1	685	3832	4–6 min	PACE
T1-w VIBE before contrast	Axial	2.5	1.92	4.29	17–22 s	BH
T1-w VIBE post contrast^a	Axial	2.5	1.92	4.29	20 min	BH

PACE: prospective acquisition correction navigator-triggered; BH: breath-hold.

^a 0.1ml/kg body weight of gadoxetic acid (Primovist, Bayer Healthcare); injection rate of 1 mL/sec followed by a bolus of 20 mL saline flush. Only portal venous phase, transitional phase (3 min) and hepatobiliary phase (20 min) was used for the study protocol.

Figure 1. Gadoxetic acid-enhanced liver MRI examination of a 65-year-old male patient with PSC. Sequences included in imaging set with MRCP is depicted in (a) and without MRCP in (b). Both readers evaluated each data set in two-time points simultaneously and at two separate reading sessions.

Table 3. Interpretation of radiological course of morphological changes of common bile duct and common hepatic duct (CBD/CHD), right-sided (RIHBD) and left-sided intrahepatic bile ducts (LIHBD) between two serial follow-up MRI examinations for imaging set with MRCP for reader A/B.

	Progression Reader A/B		Regression Reader A/B		Unchanged
	Obvious	Subtle	Obvious	Subtle
CBD and CHD	0/1	3/8	2/0	5/3	30/28
RIHBD	1/1	7/7	2/0	3/2	27/30
LIHBD	3/0	10/8	1/0	1/2	25/30

Table 4. Interpretation of radiological course of morphological changes of common bile duct and common hepatic duct (CBD/CHD), right-sided (RIHBD) and left-sided intrahepatic bile ducts (LIHBD) between two serial follow-up MRI examinations for imaging set without MRCP for reader A/B.

	Progression Reader A/B		Regression Reader A/B		Unchanged
	Obvious	Subtle	Obvious	Subtle
CBD and CHD	2/1	0/6	1/0	2/3	35/30
RIHBD	2/1	2/6	2/0	3/2	31/31
LIHBD	6/0	2/6	2/0	2/2	28/32

Table 5. Inter-reader agreement (ICC) between two serial follow-up MRI examinations for imaging sets with (+MRCP) and without MRCP (-MRCP) regarding interpretation of the radiological course of morphological changes of common bile duct and common hepatic duct (CBD/CHD), right-sided (RIHBD) and left-sided intrahepatic bile ducts (LIHBD).

Bile duct group	Inter-reader agreement, ICC (CI 95%)
	+MRCP	−MRCP
CBD/CHD	−0.449 (−1.567 to 0.204)	0.263 (−0.388 to 0.609)
RIHBD	0.074 (−0.757 to 0.511)	0.018 (−0.835 to 0.478)
LIHBD	0.224 (−0.443 to 0.587)	0.192 (−0.543 to 0.575)

Numbers in parentheses indicate 95% confidence intervals (CI).

Table 6. Intra-reader agreement (ICC) for readers A and B between imaging sets with and without MRCP regarding interpretation of the radiological course of morphological changes of common bile duct and common hepatic duct (CBD/CHD), right-sided (RIHBD) and left-sided intrahepatic bile ducts (LIHBD).

Bile duct group	Intra-reader agreement
	Reader A	Reader B
CBD/CHD	0.815 (0.650–0.902)	0.962 (0.929–0.980)
RIHBD	0.825 (0.669–0.907)	0.978 (0.959–0.988)
LIHBD	0.809 (0.638–0.899)	0.940 (0.886–0.968)

Numbers in parentheses indicate 95% confidence intervals.

Table 7. Absolute number of cases with agreement and disagreement between readers for interpretation of radiological course of morphological changes of common bile duct and common hepatic duct (CBD/CHD), right-sided (RIHBD) and left-sided intrahepatic bile ducts (LIHBD) between two serial follow-up MRI examinations for imaging sets with (+MRCP) and without MRCP (-MRCP).

	Agreement		Disagreement
	+ MRCP	− MRCP	+ MRCP	− MRCP
CBD and CHD	24	26	16	14
RIHBD	27	25	13	15
LIHBD	25	26	15	14

Figure 2. Coronal T2-weighted HASTE and 3 D MRCP (MIP) of a 38-year-old patient with PSC. Time-point 1 (b) and (d) and time point 2 (a) and (c). Reader A interpreted the radiological course of duct changes between the two time points as subtle regression whereas reader B as subtle progression.

Figure 3. Gadoxetic acid-enhanced liver MRI of a 42-year-old patient with PSC. 3 D MRCP (a), T1-weighted images in transitional phase (3 min after contrast injection) without (b) and with application of MinIP with 12 mm (c) and 16 mm (d) thick slab.