Evaluating pediatric ureteropelvic junction obstruction: Dynamic magnetic resonance urography vs renal scintigraphy 99m-technetium mercaptoacetyltriglycine

Table 1 Characteristics of the entire study cohort, n (%)

	Entire cohort, n = 126	Scintigraphy MAG-3 only, n = 28	DMRU only, n = 54	Scintigraphy MAG-3 + dMRU, n = 40	P valuea
Sex					0.837
M	88 (70)	18 (64)	38(70)	28 (70)
F	38 (30)	10 (36)	16 (30)	12 (30)
Age at diagnosis, months	22 (8-112)	8 (4-70)	29 (8-119)	30 (14-127)	0.0471
Diagnosis
Prenatal	83 (66)	18 (64)	30 (55.5)	31 (77)	0.146
Postnatal	43 (34)	10 (36)	24 (44.5)	9 (21.5)
Associated anomalies					0.0476
Duplication of urinary system	3 (2.4)	0	3 (5.5)	0
Ureterocele	0	0	0	0
Single kidney	2 (1.6)	0	1 (2)	1 (2.5)
Horseshoe kidney	1 (0.8)	0	1 (2)	0
Vesicoureteral reflux	3 (2.4)	0	0	3 (7.5)
Pyelonephritis	21 (17)	2 (7)	12 (22)	7 (17.5)	0.241
Urinary stones	3 (2.4)	1 (4)	1 (2)	1 (2.5)	0.999
Follow-up, months	11 (3-23)	8 (3-27)	11 (4-19)	12 (5-20)	0.966

^aP value: Common presentation of ureteropelvic junction obstruction in the entire study cohort (P < 0.05 was considered statistically significant).

Values are presented as median (interquartile range) or n (%), as appropriate. dMRU: Dynamic contrast-enhanced magnetic resonance urography; F: Female; M: Male; MAG-3: 99m-technetium mercaptoacetyltriglycine.

Table 2 Decision-making for surgical correction of ureteropelvic junction obstruction, n (%)

	MAG-3 primary, n = 30 (75)	DMRU secondary, n = 30 (75)	DMRU primary, n = 10 (25)	MAG-3 secondary, n = 10 (25)
Affected kidney	42 (28-48)	42 (22-50)	22 (15-40)	38 (31-45)
Age, months	13 (4-48)	29 (9-109)	41 (11-129)	12 (4-116)
Affected renal size, mm
RUS	28 (24-35)	XY	28.5 (13)	XY
MRI		28 (21-35)
Before furosemide		30 (24-38)		26 (11)
After furosemide				30 (17)
Surgical decision	No	Yes	No	Yes

Values are shown as median (interquartile range). DMRU: Dynamic contrast-enhanced magnetic resonance urography; MAG-3: 99m-technetium mercaptoacetyltriglycine; MRI: Magnetic resonance imaging; RUS: Renal ultrasonography.

Table 3 Characteristics of the patients enrolled in the study (n = 40), n (%)

	Scintigraphy MAG-3 + dMRU, n = 40	Group A < 10% discrepancy, n = 31	Group B > 10% discrepancy, n = 9	P valuea
Sex				0.697
M	28 (70)	21 (75)	7 (25)
F	12 (30)	10 (83)	2 (17)
Age at surgery, months	30 (14-127)	37 (14-134)	27 (13-76)	0.641
Diagnosis				0.0897
Prenatal	31 (77.5)	22 (71)	9 (29)
Postnatal	9 (22.5)	9 (29)	0
Associated anomalies				0.999
Duplication of urinary system	0	0	0
Ureterocele	0	0	0
Single kidney	1 (2.5)	1 (3)	0
Horseshoe kidney	0	0	0
Vesicoureteral reflux	3 (7.5)	1 (3)	2 (22)	0.999
Pyelonephritis	7 (17.5)	6 (19)	1 (11)	0.999
Urinary stones	1 (2.5)	1 (3)	0	0.999
Follow-up, months	12 (5-20)	10 (3-16)	19 (10-26)	0.05

^aP value: Potential risk factors for a discrepancy in renal function between group A and group B (P < 0.05 was considered statistically significant).

Values are shown as n (%) or median (interquartile range), as appropriate. Group A: Discrepancy in renal function between scintigraphy and dynamic contrast-enhanced magnetic resonance urography (dMRU) is < 10%. Group B: Discrepancy in renal function between scintigraphy and dMRU is > 10%. dMRU: Dynamic contrast-enhanced magnetic resonance urography; MAG-3: 99m-technetium mercaptoacetyltriglycine; F: Female; M: Male.

Table 4 Discrepant characteristics of group A and group B, n (%)

	Scintigraphy MAG-3 + dMRU, n = 40	Group A < 10% discrepancy, n = 31	Group B > 10% discrepancy, n = 9	P value
Number of discrepancies	6.5 (2-9.8)	4 (2-8)	18 (12-24)	< 0.0001
Side				0.999
Right	13 (33)	10 (32)	3 (33)
Left	27 (67)	21 (68)	6 (67)
Renal transit (affected), s	100 (67-120)	100 (60-120)	100 (70-180)	0.359
Ureteral transit (affected), s	240 (180-511)	240 (180-520)	406 (300-511)	0.285
Affected renal size, mm
RUS	28 (23-36)	29 (24-36)	24 (22-32)	0.381
MRI
Before furosemide	28 (22-35)	31 (21-35)	25 (23-31)	0.652
After furosemide	30 (24-40)	29 (24-42)	32.5 (25-36)	0.966
Follow-up, months	12 (5-20)	10 (3-16)	19 (10-26)	0.05

Values are presented as median (interquartile range) or n (%), as appropriate. dMRU: Dynamic contrast-enhanced magnetic resonance urography; MAG-3: 99m-technetium mercaptoacetyltriglycine; MRI: Magnetic resonance imaging; RUS: Renal ultrasonography.