Total body MR angiography and atherosclerosis.

The early detection of atherosclerotic vascular lesions is very important for diagnostic and interventional purposes. Traditionally, Digital Subtraction Angiography (DSA) is considered the reference diagnostic technique, but recently several new non-invasive procedures have been developed, like Doppler US, CT-angiography and MR-Angiography (MRA). MRA has progressively gained acceptance as a valid alternative. At present, the use of fast sequence and contrast injection allows to acquire segmental volumes within a few seconds (10-20s), with high diagnostic quality and accuracy. The systemic distribution of atherosclerosis requires the use of techniques which can assess the arterial system as exhaustively as possible. A MRA scanning protocol including all arteries from the epiaortic branches to the calf has recently been proposed with encouraging preliminary results. In this article, the relevant technical concepts in MRA and the present most important clinical findings are reported and discussed, including the proposed technique for a whole-body MR angiographic assessment of the atherosclerotic patient.

The role of magnetic resonance angiography in the diagnosis of subclavian steal.

PURPOSE: To compare magnetic resonance angiography (MRA) with digital angiography for diagnosis of subclavian steal syndrome. METHODS: A comparison study between MRA and digital contrast arteriography was carried out in 10 patients with suspected subclavian steal syndrome. Two of these patients were studied by MRA before and after percutaneous transluminal angioplasty (PTA). MRA was obtained on a 1.5 tesla superconductive magnet with linear head coil using a fast low angle shot (FLASH 2D) sequence in the axial plane as well as a fast imaging with steady state precession (FISP 3D) with velocity compensation gradient echo sequence in the coronal plane. The coronal images were used as source data for the construction of projection images with the use of a maximum-intensity pixel algorithm. The images were rotated from -45 degrees to 45 degrees in 15 degrees steps. RESULTS: All 10 patients had evidence of proximal subclavian artery obstruction and flow reversal in the ipsilateral vertebral artery. On MRA, consistent visualization of the affected vertebral artery in the FLASH 2D sequences and nonvisualization in the FISP 3D sequences was interpreted as an indirect sign of subclavian steal. The subclavian artery obstruction could not be assessed due to field size limits of MRA. CONCLUSION: MRA allows determination of flow reversal in the diagnosis of subclavian steal.

[Comparative evaluation of 2 non-ionic contrast media, iopentol (350 mgI/ml) and iopamidol (370 mgI/ml) in coronary angiography]. / Valutazione comparativa di due mezzi di contrasto non ionici, iopentolo (350 mgI/ml) e iopamidolo (370 mgI/ml) in cardio-angiografia.

This randomized double-blind comparative study was designed to investigate the safety and efficacy of a new nonionic monomeric contrast agent, Iopentol 350 mgI/ml, versus a nonionic monomeric contrast agent currently used, Iopamidol 370 mgI/ml, in cardioangiography. Blood pressure, heart rate, end-diastolic left ventricular and mean aortic pressure, ECG, adverse reactions and discomfort were the safety variables recorded; technical adequacy and diagnostic yield were the efficacy variables recorded. A hundred patients entered the trial and were subdivided into two groups of 50 patients each; all of them were included in the safety and efficacy assessments. Demographic data, general and background characteristics and procedural data were comparable in the two treatment groups. No significant difference in efficacy was observed between the two groups: diagnostic yield was optimal in 90% of the patients in the Iopentol group and in 88% of the patients in the Iopamidol group. Systolic blood pressure 30 min. after the examination showed, in both groups, a slight but statistically significant reduction relative to baseline values (-3.48 mmHg and -3.85 mmHg in the Iopentol and in the Iopamidol group, respectively), while no significant reduction was observed in diastolic blood pressure. A statistically but not clinically significant decrease in heart rate was observed in the Iopamidol group 30 min. after the examination (-5.05%), while this variable remained practically the same in the Iopentol group (-0.58%). No difference was found between the two groups relative to the incidence of discomfort following the injection. Other adverse reactions were experienced by 7 patients in the Iopentol group and by 9 patients in the Iopamidol group: they all promptly recovered after medical treatment, with no sequelae. All but one event in the Iopamidol group (chest and abdominal pain with ECG changes) were mild to moderate and mainly related to the procedure and to the underlying disease. In conclusion, both contrast agents are safe and effective for use in cardioangiography.

[Carotid bifurcation: angiography with magnetic resonance versus carotid angiography]. / Biforcazione carotidea: angiografia con risonanza magnetica versus carotidografia.

The reliability of Magnetic Resonance Angiography (MRA) was investigated in the study of stenosis and obstruction of carotid bifurcation; digital carotidography was the gold standard. Twenty-five consecutive patients with clinical suspicion of cerebrovascular insufficiency entered the study. MRA was performed with a 1.5 T superconductive magnet (Magnetom Siemens) and a linear head coil. The TOF 3D (FA 20 degrees, TR 30 ms, TE 7 ms) technique was applied. Images were acquired on the sagittal plane and rotated in postprocessing according to MIP on the z axis from 60 to 120 degrees (step 5). MRA exhibit 80.5% sensitivity, 96% specificity, 89.4% accuracy, 94.7% positive predictive value and 86.3% negative predictive value. When calculating the interrupted flow relative to hemodynamically significant stenoses (range 31%-occlusions), MRA sensitivity was 80.5%, specificity 100%, negative predictive value 86.3%, positive predictive value 94.7% and overall diagnostic accuracy 91.2%. MRA is to be considered a diagnostically reliable procedure in the study of carotid bifurcation and its diagnostic accuracy may even be increased in the future by the possible assessment of over- and underestimated cases.

[Nontraumatic dissection of the left extracranial internal carotid artery. A clinical case]. / Dissecazione non traumatica dell'arteria carotide interna extracranica di sinistra. Caso clinico.

The authors report a case of non traumatic dissection of the left extracranial internal carotid artery. Their main topics deal with the clinical-diagnostic aspects and the therapeutic approaches adopted, compared with the specific literature's most recent data. In addition they have discussed--some--investigations aimed at the best follow-up of those diseases.

[Comparison of magnetic resonance angiography and digital angiography of the epiaortic vessels]. / Confronto angiografia a risonanza magnetica-angiografia digitale dei vasi epiaortici.

Atheromasic lesions and other pathologic conditions of the arterial vessels of the neck are the most frequent causes of cerebrovascular disease. Diagnostic imaging currently employs digital subtraction angiography (DSA), Doppler, and color-Doppler US to study these conditions. Digital subtraction intraarterial angiography (DSAA) can provide both an early diagnosis and an accurate preoperative depiction of neck vessels; however, in spite of its effective value, it still remains an invasive technique. Magnetic Resonance angiography (angio-MR) is the latest technique allowing the depiction of neck vessels morphology. It shares with digital angiography the capability of supplying spatial depiction of all the examined vascular structures, and with US its noninvasiveness. The authors investigated angio-MR capabilities in providing accurate and detailed images of neck arteries; the images were then compared with DSA ones. Thirty patients with cerebrovascular diseases were studied. MR imaging was performed with a 1.5 T unit with a dedicated coil, and gradient-echo sequences were employed. Refocused sequences for flow were acquired on both the coronal and the sagittal planes, with the following parameters: TR 40, TE 10, flip angle 25 degrees, acquisition volumes 80-35 mm, 64-15 frames. Digital angiography demonstrated 101 vascular lesions: 27 slight stenoses (less than 30%), 19 mild stenoses (31-70%), 12 severe stenoses (71-99%), 7 occlusions, 14 coilings, 7 kinkings, and 15 hypoplasias of vertebral artery. In slight stenoses, angio-MR underestimated the condition in 11/27 patients. In mild and severe stenoses, as well as in occlusive diseases, angio-MR tended to overestimate the condition. In coiling, kinking, and hypoplasia, angio-MR yielded the same results as DSA.

[Surgical and radiological intervention in the treatment of peripheral arteriovenous fistulas]. / Chirurgia e radiologia interventistica nel trattamento delle fistole artero-venose periferiche.

The Authors report five examples of arteriovenous fistulas examined in the last two years. The different aetiology concerning these lesions, the most suitable diagnosis and the therapeutic tactics are examined and discussed. When they present results and considerations, they show optimism and discrete realism about results and prognosis as a consequence of technological progress and more and more common multidisciplinary approach towards this pathology.

[Magnetic resonance angiography of the neck vessels: technique and anatomy]. / Angiografia a risonanza magnetica dei vasi del collo: tecnica e anatomia.

The authors identified the standard projections for studying neck vessels with magnetic resonance angiography. Sixty volunteers underwent angio-MR of the arterial neck vessels with FISP 3D FT sequences obtained on the coronal and sagittal planes. The gradient-echo sequence (FISP 3D FT) was acquired with TR = 0.04-0.08 s and TE = 15 ms, with 25 degrees flip angle. Single excitated slices of thickness ranging from 1-2 mm were included in the acquisition volume. These sequences were subsequently processed by the maximum intensity projection method. Two radiologists examined our results to choose the optimal projections. We used a semiquantitative scale which allowed us to distinguish 3 different diagnostic levels for each projection: well-visualized vessels, poorly-visualized, and non-visualized ones. For each section axial rotations were performed ranging from 0 degree to 180 degrees, with 15 degrees intervals. On the coronal plane, rotations from -45 degrees to 45 degrees were the optimal ones to visualize the studied vessels. The 0 degree-15 degrees-30 degrees-45 degrees-135 degrees-165 degrees-180 degrees projections allowed the common carotids to be clearly demonstrated together with the vertebral arteries. The other projections appeared to be useless for diagnostic purposes. On the sagittal plane, rotations from 60 degrees to 120 degrees were the optimal ones. The 90 degrees projection allowed the demonstration of all the big arterial vessels of the neck, including carotid bifurcation and internal and external carotids. The assessment of the optimal diagnostic projections for angio-MR of the neck vessels is helpful to reduce post-processing time. As a matter of fact, the immediate visualization, during the examination, of the standard projections allows further acquisitions to be obtained--if needed--to try to solve specific diagnostic doubts.