Renal artery aneurysms: diagnosis and surveillance with 3D contrast-enhanced magnetic resonance angiography

Abstract

The use of contrast-enhanced magnetic resonance angiography (CE-MRA) in screening for suspected renovascular disease may result in increased detection of renal artery aneurysms. We report the CE-MRA findings at diagnosis and follow-up in nine hypertensive patients with unsuspected renal artery aneurysms. A search of renal CE-MRAs of suspected renal artery stenosis at two tertiary referral institutions over 5 1/2 years was performed. All patients underwent CE-MRA using a fast spoiled gradient echo technique (TR/TE/flip 5.1-6 ms/1.6 ms/40 degrees), scan matrix 512 x 196-224, 1 excitation, FOV 400-450 mm x 266-360 mm, 32-50 mm x 1.5-2 mm interpolated slices. Gadolinium-enhanced 3D images were obtained during breath holding. Images were evaluated and post-processed on a workstation by a single operator. Nine patients with renal artery aneurysms out of a total of 912 cases were found, all involving the main artery or divisions proximal to the renal hilum. Renal arteries distal to the hilum were not consistently visualized. The aneurysm was bilobed in one patient, multilocular in another and unilocular in all others. Severe stenosis of the renal artery proximal to the aneurysm was present in two. Four patients underwent follow-up showing no change in aneurysm size. CE-MRA reliably identifies aneurysms involving the main renal arteries and proximal branches. Once diagnosed, CE-MRA offers a safe, non-invasive modality for surveillance of aneurysm if active intervention is not planned.

Role of Percutaneous Needle Biopsy for Renal Masses

“…Use of flowsensitive MR pulse sequences (e.g., time of flight), identification of MRI flow voids, and/or application of Doppler ultrasound can establish the correct diagnosis. 36,37 Although the technical success rate of percutaneous biopsy is excellent for solid renal masses, the data are not as robust for complex cystic masses, specifically Bosniak III cystic masses. 3 Use of biopsy in this setting is controversial, with some centers advocating its use and others arguing against it.…”

Renal MR Angiography

“…The clinical relevance of renal artery aneurysms is uncertain; however, the risk of rupture increases with increasing diameter, and MRA provides a safe, non-invasive technique for their detection and characterization (Fig. 14.7a, b ) [ 38 ].…”

Técnicas e Táticas no Tratamento Endovascular do Aneurisma da Artéria Renal

“…1,2 Na última década, com o uso de métodos diagnósticos não invasivos, como a ultrassonografia Doppler (USG-D) e a angiotomografia computadorizada (TC), o número de casos diagnosticados vem aumentando. 3 Embora a história natural dos AAR seja pouco conhe cida, e os sintomas sejam inespecíficos ou inexistentes, complicações potenciais, como embolização e ruptura, são relatadas em 5 a 10% dos casos, levando a uma taxa de mortalidade elevada, especialmente em mulheres grávidas ou em pacientes com poliarterite nodosa (PAN). 4,5 Dessa maneira, as indicações para o tratamento incluem pacientes sintomáticos, mulheres gestantes ou em idade fértil, e pacientes assintomáticos com aneurismas > 2 cm ou com PAN.…”

“…4,5 Dessa maneira, as indicações para o tratamento incluem pacientes sintomáticos, mulheres gestantes ou em idade fértil, e pacientes assintomáticos com aneurismas > 2 cm ou com PAN. 3,6 Tanto o tratamento cirúrgico convencional como o autotransplante renal apresentam taxa de mortalidade variando de zero a 4%, com taxa de complicação de 10 a 30%. 7,8 Nos últimos anos, com o progresso do tratamento endovascular e o desenvolvimento de novos dispositivos, os AARs têm sido abordados com menor morbimortalidade e com a preservação da árvore vascular nativa.…”

“…9 Entretanto, no acompanhamento pós-operatório, a TC apresenta limites para a visualização adequada das molas e dos vazamentos, em razão dos artefatos gerados pela presença do metal, 17 sendo o USG-D e a angiorressonância os métodos adequados para o seguimento desses pacientes. 3,9 A experiência adquirida com o manejo endovascular das estenoses da artéria renal contribuiu para o aprendizado na abordagem endovascular dos AAR. 18 Estudos com o tratamento endovascular desses aneurismas são restritos a casuísticas pequenas ou relatos de caso.…”