Radiologic Assessment of Native Renal Vasculature: A Multimodality Review.

A wide range of clinically important anatomic variants and pathologic conditions may affect the renal vasculature, and radiologists have a pivotal role in the diagnosis and management of these processes. Because many of these entities may not be suspected clinically, renal artery and vein assessment is an essential application of all imaging modalities. An understanding of the normal vascular anatomy is essential for recognizing clinically important anatomic variants. An understanding of the protocols used to optimize imaging modalities also is necessary. Renal artery stenosis is the most common cause of secondary hypertension and is diagnosed by using both direct ultrasonographic (US) findings at the site of stenosis and indirect US findings distal to the stenosis. Fibromuscular dysplasia, while not as common as atherosclerosis, remains an important cause of renal artery hypertension, especially among young female individuals. Fibromuscular dysplasia also predisposes individuals to renal artery aneurysms and dissection. Although most renal artery dissections are extensions of aortic dissections, on rare occasion they occur in isolation. Renal artery aneurysms often are not suspected clinically before imaging, but they can lead to catastrophic outcomes if they are overlooked. Unlike true aneurysms, pseudoaneurysms are typically iatrogenic or posttraumatic. However, multiple small pseudoaneurysms may be seen with underlying vasculitis. Arteriovenous fistulas also are commonly iatrogenic, whereas arteriovenous malformations are developmental (ie, congenital). Both of these conditions involve a prominent feeding artery and draining vein; however, arteriovenous malformations contain a nidus of tangled vessels. Nutcracker syndrome should be suspected when there is distention of the left renal vein with abrupt narrowing as it passes posterior to the superior mesenteric artery. Filling defects in a renal vein can be due to a bland or tumor thrombus. A tumor thrombus is most commonly an extension of renal cell carcinoma. When an enhancing mass is located predominantly within a renal vein, leiomyosarcoma of the renal vein should be suspected. ©RSNA, 2017.

Assessment of availability of magnetic resonance angiography (MRA) in renal arteriovenous fistula.

We report two cases of cirsoid-type renal arteriovenous fistula (RAVF) which were difficult to differentiate from renal pelvic tumor by intravenous pyelogram (IVP) and computed tomography (CT) scan. Two women visited our department complaining of sudden asymptomatic macroscopic hematuria. CT scans showed an irregular mass in the right kidney. Magnetic resonance angiography (MRA) revealed a cirsoid-type RAVF. These patients were treated with transarterial embolization (TAE) using ethanol, geratin sponge, and a coil. It is suggested that MRA is useful for the diagnosis of renal arteriovenous fistula.

Interruption of the inferior vena cava with azygos/hemiazygos continuation accompanied by distinct renal vein anomalies: MRA and CT assessment.

We report a case of interruption of the inferior vena cava with azygos/hemiazygos continuation and additional variations of the renal veins, an uncommon developmental anomaly. Magnetic resonance angiography and computed tomography, in association with clinical awareness, can be used to diagnose this entity.

Assessment of living renal donors with spiral CT.

PURPOSE: To determine whether spiral computed tomography (CT) can be used to evaluate potential living renal donors. MATERIALS AND METHODS: Twelve potential living renal donors underwent spiral CT and conventional arteriography. CT angiography was performed with 30-second spiral acquisition during injection of 150 mL of nonionic iodinated contrast material into an antecubital vein at 5 mL/sec. Five minutes after injection, a frontal abdominal scout projection was obtained to assess the renal collecting system. Results of blinded interpretations of axial CT angiograms, three-dimensional CT angiograms, and conventional arteriograms were correlated with intraoperative findings in 11 cases. RESULTS: Axial and three-dimensional CT angiography were 100% sensitive for identifying seven accessory renal arteries and 14% and 93% sensitive for identifying five prehilar renal artery branches. Renal venous anomalies were confirmed in three patients at surgery. Operative management changed in four of 11 patients who underwent donor nephrectomy. CONCLUSION: Spiral CT holds promise as a single examination for anatomic assessment of living renal donors.

Assessment of major venous anomalies by computerized tomography.

Congenital anomalies of major venous structures are not common but their identification and relative position, particularly in relation to an abdominal aortic aneurysm, are of significant value in planning and conducting aortic operations. Computed tomography (CT) has become a common method of preoperative evaluation of aortic disease. Its reliability in providing accurate information regarding aneurysmal size, configuration, and extension, as well as the presence of intraluminal thrombus and involvement of the renal and iliac arteries, has been demonstrated. Simultaneous visualization of the major adjacent venous structures with the use of contrast enhancement is obtained, but anatomic variants can be overlooked because they are commonly subtle and considered incidental. The preoperative diagnosis of these venous abnormalities is significant to the vascular surgeon. Such information can be accurately and reliably acquired with the present CT techniques without the need for further diagnostic studies.

Retrograde flow in the left gonadal vein at abdominal angiography: an anatomo-physiological review and clinical assessment.

Retrograde flow in the left gonadal vein may be visualized in the venous phase of aortography or renal arteriography. In none of 13 cases was this due to a mass lesion at the renal hilum. Although the Valsalva maneuver may cause this flow reversal in some, in most cases it is due to anatomical structures or variants compressing the renal vein. These are detailed. Left gonadal vein reflux incidentally detected on the aortogram may thus indicate impaired left renal venous drainage and its consequences. There are also clinical and urographic constellations which merit aortography to detect left gonadal vein reflux for their elucidation.