[Usefulness of magnetic resonance angiography in the diagnosis of polar vessel in stenosis of the pyeloureteral junction].
OBJECTIVE
To present the results of a prospective study that had been conducted to determine the accuracy of magnetic resonance angiography (MRA) in the detection of accessory or polar vessels associated with ureteropelvic junction (UPJ) stricture, in order to utilize the most appropriate surgical procedure in the management of this condition.


METHODS
From October, 1994 to September, 1996, 30 MRA procedures were done in 12 males and 18 females, aged 14 to 73 years (mean 38.12), with symptomatic UPJ obstruction. When the MRA was positive for polar vessels, the patients underwent open dismembered pyeloplasty; surgical correlation and a true positive result could be established. Percutaneous endopyelotomy was offered when the MRA was negative. The findings at open surgery and an unremarkable clinical course and radiological findings at one year follow-up established a true negative result.


RESULTS
Accessory or polar vessels (11 arteries; 4 veins) were found in 11 patients (36.4%). MRA had a sensitivity of 92.3% (15/16) for detection of accessory vessels. Fourteen patients underwent open surgery (11 dismembered pyeloplasties; 3 nephrectomies) and the MRA findings were confirmed in each case (8 positive; 6 negative). Surgery disclosed an accessory vein that had not been detected on MRA in only one patient. This patient also had a polar artery that had been observed on MRA and demonstrated at surgery; thus, the sensitivity of MRA for detection of UPJ stenosis with polar vessel is 100% (11/11). Each vessel described on MRA was confirmed at surgery; there were therefore no false positives and the specificity was 100%.


CONCLUSIONS
Although this is a preliminary study with a short follow-up and with some limitations, the results indicate that MRA is a simple, non-invasive technique with a high sensitivity and specificity for detection of polar vessels associated with UPJ stenosis, and appears to be a useful preoperative diagnostic procedure due to the surgical implications.
Pereira Arias
J G
JG
Servicio de Urología, Hospital de Galdakao, Vizcaya, España.
Ibarluzea González
J G
JG
Capelastegui Alber
A
A
Astigarraga Aguirre
E
E
Gallego Sánchez
J A
JA
Larrinaga Simón
J
J
Bernuy Malfaz
C
C
D000293:Adolescent; D000328:Adult; D000368:Aged; D001808:Blood Vessels / Q000002:abnormalities; D005260:Female; D006801:Humans; D007682:Kidney Pelvis; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014513:Ureter / Q000098:blood supply*; D014517:Ureteral Obstruction / Q000175:diagnosis*
Utilidad de la angioresonancia magnética en el diagnóstico del vaso polar en la estenosis de la unión pieloureteral.