Guidelines for the assessment of the visceral arteries and veins and of the renal artery

Investigations — Continuous wave Doppler (CWD) — Duplex scanning (DS) — Color-coded duplex scanning (CDS) — Standard radiography (Xray) — Angiography by computed tomography (AngioCT) — Angiography by magnetic resonance (AngioMR) — Digital subtraction angiography (DSA) The celiac trunk (CTr) and superior mesenteric artery (SMA) are not frequently affected by atheromatous type steno- obstructive disease and even when they are, patients remain free from symptoms for a long time due to the presence of a rich collateral circulation between CT, SMA me and inferior mesenteric artery (IMA) and between these vessels and the aortic circulation, through gastric and haemorrhoid arteries. At present the use of CDS investigation is required in the following conditions: a) chronic obstructive mesenteric disease and secondary ischemia; b) occlusive or aneurysmatic disease of the abdominal aorta and iliac arteries; c) portal hypertension; d) aneurysms of the visceral arteries; e) control of surgical repair of the visceral arteries and of a porto-caval shunt or other surgical anastomosis per- formed to reduce portal blood pressure. The first procedure, in addition to clinical assessment, is CDS, reserving radiological imaging to the study of an- eurysms and/or lesions that can only be poorly assessed by ultrasounds. Investigation with CDS is the only non-invasive meth- od that allows for the diagnostic definition of visceral arte- rial lesions and is an objective method by which to monitor the results of reconstructive surgery, by-pass or angioplasty. The advantage of the CDS mainly consists in the highlight-ing of the presence of flow also in areas where two-dimen- sional resolution is poor and therefore it is correctly guid- ing the haemodynamic study with pulsed Doppler.The sensitivity and specificity in the diagnosis of ste- nosis is increased by the use of US amplifier. The reliability of such investigation is increased by the association with CDS without amplifier. Argalia et al. reported sensitiv- ity and specificity of 75% and 70.1% with CDS, of 100% and 87.5% with the use of an amplifier and, respectively, of 100% and 91.6% with angio-MR7, reporting accuracy in the diagnosis of haemodynamic stenosis of 50% with the standard CDS and 75% with an amplifier, whilst the view- ing of normal or minimally pathological arteries was 94% with the standard examination and 97% with the use of an amplifier. [According to Cianci et al., contrast means does not improve diagnostic reliability in ostial stenosis. The use of an amplifier in patients with uncertain diagno- sis results in a certain diagnosis with possible etiological treatment and related reduction of drug costs. Even in expert hands, a good view of the CTr and SMA can be obtained in 80-95% of cases, and controlled studies with angiography, both in multilevel disease patients and in symptomatic patients have shown a high level of accu- racy of US investigation. Variations of the origin and ana- tomical anomalies of the visceral vessels are so frequent, and the range of normal and abnormal flow velocity is so broad, that the duplex parameters reported by studies on healthy volunteers do not automatically apply. In terms of visceral vessels too, radiological imaging, and particularly AngioMR is proposed more and more fre- quently in literature in lieu of angiography.