Biomedical subjects

C Di Stasi

Publications and source records attributed to C Di Stasi.

28 records · Page 2Linked to original sources

PubMedDate not supplied

Carcinoma of the pancreatic head area. Therapy: nonoperative biliary drainage for palliation.

Jaundice is the dominant symptom in patients with biliary obstruction from carcinomas of the pancreatic head area. The many symptoms usually associated to prolonged biliary stasis (malnutrition, coagulopathy, pruritus hepatocellular failure, renal dysfunction, angiocolitis) is commonly resolved or relieved by biliary drainage. Palliation is frequently the only feasible treatment in these patients due to the biological aggressiveness of these tumors characterized by the early infiltration of adjacent tissues. Endoscopic and percutaneous procedures of biliary recanalization are as effective as those of surgical palliation, are more comfortable to the patients and burdened with a lower morbidity and mortality. In selected patients, palliation of jaundice can be combined with intraluminal radiotherapy or pancreatic drainage the latter aimed at the relief of the "obstructive" pain present in some patients with carcinoma of the area of the head of the pancreas.

Combined Modality Therapy↗

PubMedDate not supplied

[The role of Doppler US in the study of carotid system].

Color Doppler US is at present the most reliable noninvasive procedure in the diagnosis of carotid disease and plays a major diagnostic role in the patient at risk for stroke. The anatomofunctional relationships of carotid and vertebrobasilar system suggest a diagnostic combination between Doppler US and transcranial Doppler for complete hemodynamic evaluation of normal and pathologic cerebral vessels. The most relevant disease, as the cause of stroke, is represented by internal carotid atherosclerosis. Mechanisms by which the atheromatous plaque represents a cause of ischemia involve two factors: the embolic factor and the hemodynamic factor. The embolic factor is consequent on unstable plaques and US plays a major role in plaque characterization. Stenotic plaques are the major cause of the hemodynamic factor. Color Doppler US inables quantification of stenosis and selects surgical patients with greater than 70% stenosis. In internal carotid dissection as the acute cause of cerebrovascular insufficiency color Doppler US findings are significant for early diagnosis and follow-up.

Blood Flow Velocity↗

PubMedDate not supplied

Epidemiology, pathophysiology and natural history of venous thromboembolism.

Venous thromboembolism is a relevant social and health care problem for its high incidence, pulmonary embolism-related mortality, and long-term sequels which may be disabling. In the United States, there are at least 100,000 deaths per year from pulmonary embolism, found in over 10% non selected autopsy findings. The use of noninvasive diagnostic procedures has improved our knowledge on venous thromboembolism, with reference to surgery in particular. Deep vein thrombosis represents one of most common postoperative complications. Fatal pulmonary embolism is observed at least in one over thousand operated patients. From data of literature and in the authors' experience, the incidence of pulmonary embolism is decreasing in last years. Deep vein thrombosis is caused by several factors associated with Virchow's triad. Its evolution is site-related. While deep vein thrombosis of the calf can be considered a "benign" pathological condition for the incidence and severity of the embolic complication, as well as for the long-term outcomes, when the proximal venous trunks are involved, it is related to a high incidence of severe pulmonary embolism and relevant postphlebitic sequels. Pulmonary embolism is often the first manifestation of thromboembolism. Mobilization of thrombi is easier in the first phases, when they do not adhere as yet to the venous wall. Of 52 consecutive cases of pulmonary embolism, 21% occurred in the absence of signs or symptoms of deep vein thrombosis. In rare cases, thrombosis may be massive with total block of venous return flow and onset of ischemia. These forms have a severe prognosis apart from the embolic complication.

Humans↗

PubMedDate not supplied

Diagnostic imaging in deep vein thrombosis of the limbs.

The clinically suspected deep vein thrombosis (DVT) should always be confirmed by instrumental procedures. In fact, about 70% of patients with clinically suspected DVT are shown to be negative on instrumental investigations. Phlebography is still the gold standard in the diagnosis of peripheral DVT. Main phlebographic findings are: persistent filling defect; abrupt interruption of contrast in a vein; lack of opacification in all or some deep veins; flow diversion with opacification of collateral branches. At present, peripheral phlebography is performed when the other noninvasive exams (Color Doppler US and Duplex Doppler) are doubtful, technically limited or when thrombosis of innominate veins or superior vena cava, is suspected. Real-time US enables direct visualization of the limb proximal veins. The venous wall, the venous valves, the thrombus and its development, the anatomic variants, the perivenous structures which may impact on the normal physiology of venous return, are depicted. However, the distal veins of the leg and arm and deep veins (the iliac veins, the superficial femoral vein in the adductor canal) are not accurately visualized. The US findings in DVT include: the presence of echoes within the vascular lumen; the veins in axial scans are not compressible. Pulsed Doppler and duplex Doppler combine the morphologic and functional study. Injury caused by DVT at the valvular level (postphlebitic syndrome) is visualized. Primary deep vein thrombosis caused by valvular disorders (valvular aplasia) is identified. Inadequate superficial and perforating veins to be treated with surgery are mapped. Color Doppler US depicts directly superficial and deep limb veins combining the morphologic with the functional assessment represented by the visualization of the map of flow velocity and direction. Recently, a new diagnostic procedure, the color Doppler Energy (CDE) or Power Doppler has been introduced. Together with mean flow velocity and spectral variance, the signal energy or power is also analyzed. The CDE is independent of the US incidence angle, it does not shows the flow direction, detects particularly slow flows, early canalization of thrombi and non occlusive thrombosis. Color Doppler diagnosis of thrombosis is prompt because an area with absence of color is visualized. Collateral vessels and flow direction within them, is well depicted. Beside the site and extension of thrombosis, color Doppler US is able to directly visualize the distal end of the thrombus, which when floating is at high risk for embolism. CT allows an adequate study of the iliocaval axis and is useful if phlebography or color Doppler US are not diagnostic. Iliocaval thrombosis represents a not infrequent finding during abdominal CT. The thrombus appears as a hypodense mass encircled by the hyperdense rim of contrast medium.

Humans↗

PubMedDate not supplied

Interventional radiology in the treatment of pulmonary embolism.

Percutaneous therapy of pulmonary embolism is performed by local administration of thrombolytic agents or by mechanical canalization. The latter is achieved by fragmentation of the embolus with angiographic catheters, or by aspiration or fragmentation of the thrombus with dedicated devices. The pharmacologic basis of locoregional administration of thrombolytic agents, as in the treatment of deep vein thrombosis, is the possibility of reaching a higher concentration of the drug at the level of the embolus by decreasing the activity of systemic fibrinolysis, thus lowering the incidence of hemorrhagic complications. In recent years, locoregional thrombolytic therapy has been used only combined with mechanical canalization. The easiest way is direct fragmentation of the embolus with an angiographic catheter. The system of aspiration of pulmonary emboli, experimented by Greenfield is based on the use of a flexible catheter the tip of which is equipped with a plastic radiopaque cup. Recently, several rotating devices have been designed. Some have already been used for the peripheral arterial system, others are specific for the venous system (Schmitz-Rode-Gunther device). The clinical effectiveness of these devices is however still to be assessed. Other non conventional possibilities for the mechanical canalization of pulmonary arterial system are represented by metal stents and angioplasty with balloon catheters. At present, interventional radiologic procedures represent an additional tool in the medical or surgical therapy of severe pulmonary embolism, when it is contraindicated or ineffective.

Catheter Ablation↗

PubMedDate not supplied

Venous interruption as prophylaxis of pulmonary embolism: vena cava filters.

Interruption of vena cava for prevention of pulmonary embolism (PE) was achieved in the past with surgical ligation or placement of clips outside the infrarenal vena cava. At present, this procedure is performed with percutaneous insertion of vena cava filters. Vena cava filters can be permanent or temporary, catheter-retrievable. Main indications for placement of a vena cava filter are: contraindication for anticoagulant therapy in patients with severe PE in whom a further embolic episode would be fatal or patients with PE (or its recurrence) undergoing adequate anticoagulant therapy. Temporary filters are reserved to patients where the risk of PE is limited in time as in posttraumatic, post-partum or postoperative thromboembolism. The incidence of recurrence after placement of a vena cava filter varies between 0.5 and 7%. Procedure-associated complications are usually mild. However, severe complications as filter migration into the pulmonary artery or vena cava perforation were described. Our experience concerns the insertion of 61 vena cava filters (47 permanent and 14 temporary). Indications were as follows: iliofemoral thrombosis at embolic risk (37 cases), contraindication for anticoagulant therapy in the presence of deep vein thrombosis with embolic risk (7 cases), protection during fibrinolytic therapy (3 cases), PE during anticoagulant therapy (5 cases) complications of anticoagulant therapy which required discontinuation (5 cases), prophylaxis in view of surgery at high risk for PE (2 cases), protection for surgical venous thrombectomy (2 cases). Mortality was nil. Clinically evident PE was not observed in any patient in whom vena cava filter was inserted. Complications were mild and asymptomatic. Vena cava filters represent an effective prevention of PE together with medical and surgical treatment. At present, problems of this procedure are not technical but rather concern correct indications. Interruption of vena cava is effective if planned within a global strategy for prevention of thromboembolism.

Adolescent↗

PubMedDate not supplied

Role of angiography in the evaluation of hepatic perfusion.

Angiography was the first method to be used for a morphofunctional study of hepatic perfusion. It can be performed with direct puncture of portal system or indirect opacification after contrast injection into the splenic artery or superior mesenteric artery. At present, direct angiographic procedures have only a historical value in the diagnostic approach while they have a preliminary role in interventional maneuvers on the portal system (TIPSS, embolization of portal branches or left gastric vein). Indirect angiographic procedures allow the study of arteries, parenchymas and portal system. Much of the information on arterial hepatic and portal circulation is now supplied by noninvasive procedures (US,CT,MRI); however in selected cases, angiography can be performed. Furthermore, the knowledge of angiographic findings of hepatic circulation is basic to the interpretation of "functional" information supplied by color-Doppler US, spiral CT and MR angiography.

Angiography↗

PubMedDate not supplied

The diabetic foot: role of color-Doppler US.

Color Doppler US is a first choice instrumental exam for the diagnosis and staging of peripheral arterial occlusive disease in diabetic patients. Normal and pathological findings are analyzed to establish the potential and limitations of the procedure. Color Doppler US is a noninvasive, reproducible and cost-effective procedure. Direct morphologic and flowmetric evaluations of stenotic-occlusive alterations, and indirect evaluations based on the interpretation of velocimetry findings proximal and distal to the lesions, are feasible. The conventional basic exam can be enhanced with the power module. Encouraging experimental results are observed with the use of echographic contrast media. Disadvantages of the procedure are related to the poor panoramic view, subjective (operator-dependent) interpretation and limitations related to the physics of ultrasound.

Diabetic Foot↗

PubMedDate not supplied

Angiography and MR-angiography in the diagnosis of peripheral arterial occlusive disease in diabetic patients.

An invasive diagnostic procedure as angiography which involves direct arterial injection of contrast through suitable catheters, is still considered the gold standard in the evaluation of diabetic patients with peripheral arterial occlusive disease. The accuracy of anatomical details is combined on angiography with a pan view, indispensable for correct therapeutic planning. MR-angiography, with the 2D time of flight sequences in particular, supplies images of great anatomical accuracy and very sensitive in the detection of occlusive lesions which compare well with angiography and superior in the assessment of the length of occluded tracts. This noninvasive, cost-effective procedure seems bound to replace angiography in the pretreatment evaluation of diabetic patients with peripheral arterial occlusive disease.

Angiography↗

PubMedDate not supplied

The role of interventional radiology in the treatment of the diabetic foot.

Although the pathologic features of arterial disease in diabetes do not differ from those of simple atheromatous lesions, the plurisegmental involvement, the predominant subpopliteal location of lesions and the association with impaired cardiac and renal function in these patients imply peculiar problems in the selection of an adequate therapy. At present, in interventional radiology a number of procedures are available for intravascular therapy (angioplasty, stent, locoregional fibrinolisis, mechanical atherectomy), particularly suitable for diabetics who are affected by multisystem impairment. These procedures are not in opposition to the conventional ones (surgical and medical) but rather integrate them, allowing to extend the indications and improve the results in the treatment of the vasculogenic diabetic foot. Based on the personal experience the potential of intravascular procedures in this disease, is analyzed.

Aged↗