Diagnosis and outcome of renal function in patients with renal artery stenosis: which role have color Doppler sonography and magnetic resonance angiography?

AIM: Minimally invasive diagnostic techniques would be useful in the preoperative diagnosis of patients with hypertension and ischemic renal disease. The aim of our study was to compare color Doppler sonography (CDS), and magnetic resonance angiography (MRA) with the reference standard, digital subtraction angiography (DSA), in the diagnosis of renal artery stenosis. METHODS: Thirty-nine patients with arterial hypertension and monolateral or bilateral renal artery stenosis documented by CDS underwent renal artery MRA and then DSA during corrective percutaneous transluminal angioplasty. CDS and MRA scans were evaluated by 3 independent observers who studied 78 main renal arteries. Stenosis of 70% or more were regarded as significant. Sensitivity, specificity, positive and negative predictive values and two-sided 95% confidence intervals of CDS and MRA for the detection of significant renal artery stenosis were calculated. The statistical significance of the differences in sensitivities between CDS and MRA was assessed by means of the kappa test (< or =1). RESULTS: CDS and MRA, therefore, both achieved 97.6% sensitivity and 100% specificity for diagnosing stenoses at the origin of the renal artery; CDS yielded 100% sensitivity and 97.1% specificity and MRA 87.5% sensitivity and 98.6% specificity for diagnosing stenosis in the intermediate distal segments. CONCLUSIONS: Statistically significant differences between CDS and MRA in the diagnosis of renal artery stenosis have not been observed. However, according to our experience, CDS is the preferred technique because it also provides useful information about the development of kidney disease before correction.

Suprarenal artery stenosis may be mistaken for renal artery stenosis in Doppler studies.

There are several limitations in using colour-flow-Doppler (CFD) to diagnose renal artery stenosis. This report describes a case of "false positive" stenosis of the renal artery diagnosed using CFD. A patient affected by arterial hypertension and with a suspected stenosis of the renal artery was examined using CFD. However, the patient was in fact suffering from suprarenal artery stenosis.

Could an echo contrast agent be helpful in identifying renal artery stenosis?

BACKGROUND: Diagnosis of renal artery stenosis using echo color-Doppler is subjected to several limitations. The aim of this study was to examine if the routine use of a contrast agent could be helpful in identifying renal artery stenosis (RAS). METHODS: We analysed 35 patients affected by RAS using an echo color-Doppler coupled with a contrast agent. All patients presented arterial hypertension, with a good drugs control, and mean serum creatinine of 1.8 mg/dL. All patients previously underwent angiography. RAS was at the origin of the artery in 27 patients, at the intermediate tract in 8. All patients had already been submitted to a basal echo color-Doppler. RESULTS: The contrast agent determined a significant increase in the average colour signal in all the subjects, and a better evaluation of the spectral waveforms, if compared to the basal examination. CONCLUSIONS: The results obtained showed that the contrast agent doesn't improve the diagnosis of RAS, especially in vascular origin stenosis, while it shows a real advantage in the intermediate or distal stenosis which are better visualized.

Color-Doppler sonography in ophthalmology.

BACKGROUND: With the present study we considered ocular blood flow by the use of color Doppler ultrasound. We compared the most clinically important arteries of both eyes. We valued the central retinal artery, the posterior long ciliary arteries, the posterior brief ciliary arteries and the central retinal vein. METHODS: We submitted to an ecd examination of the ophthalmic arteries 50 patients, of whom 30 were healthy, 4 presented a pallor of the optic disk, 6 were affected by chronic simple glaucoma and 10 were affected by arterial hypertension. RESULTS: This study has allowed us to define the normal and pathologic anatomic findings at the ecd tracing therefore qualitative and quantitative standards of this examination, repeatable and comparable. CONCLUSIONS: Currently the different techniques used to study ocular blood flow, do not allow its exact detection, but only a morphological evaluation of the eye artero-venous system. Acquisition of morphological and velocimetric data, at the same time, allows a more exact evaluation of the pathology. Therefore the ecd is a simple rapid and non-invasive approach, useful in the acquisition of important data concerning diagnostic confirmation, prognosis, and above all pharmacological follow-up of many pathologies such as diabetes, glaucoma and arterial hypertension. The diagnosed vascular alterations are correlated to the degree retinopathy and to the effectiveness of the pharmacological treatment.