Biomedical subjects
Publications and source records attributed to C Rabbia.
The authors report a case of a patient with thromboembolic strokes caused by a high internal carotid artery aneurysm. Considering the position and the anatomic structure of this aneurysm the sac was excluded transluminally by placing an endovascular covered stent.
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The authors report their experience with Palmaz stents in the percutaneous treatment of steno-obstructive iliac artery lesions. A hundred and thirty-six patients suffering from claudicatio, pain at rest or distal lesions underwent 156 percutaneous stenting maneuvers. The indications to stenting were: acute obstruction or severe dissection after angioplasty (19 cases), residual stenosis > 30% (80 cases), large ulceration (7 cases), restenosis after previous percutaneous treatment (10 cases) and finally chronic obstruction (40 cases). In 154 cases the maneuver was successful, in 2 the stent was mispositioned because of technical problems and another stent had to be inserted. In 146 cases stenting was performed after transluminal angioplasty, while 10 chronic obstructions underwent stenting with no previous angioplasty to limit distal embolization. In all cases stenting improved the angiographic pattern more than angioplasty alone. Prophylactic drugs after stenting included only anti-aggregating substances. Marked clinical improvement was observed after stenting, and almost all patients gained at least one clinical stage. During stenting, 15 complications occurred (9.6%)--i.e, 2 external iliac artery dissections, 4 mild inguinal hematomas, 1 pseudoaneurysm, 1 segmental obstruction of the superficial femoral artery and 7 distal embolisms during recanalization of chronic occlusions. The complications were caused by the procedure, and especially by the large caliber of the introducer sheat; no complication was related to the stent itself. None of these complications needed major surgery. Over 3-34 months' follow-up (mean: 9 months), 1 obstruction and 2 restenoses occurred in 134 vessels; these lesions were treated successfully with thrombolysis and/or transluminal angioplasty (primary patency: 97.8%, secondary patency: 100%). In the authors' experience, percutaneous stenting represents a simple and fast procedure with very good technical and clinical results which can increase the capabilities of percutaneous revascularization procedures.
Duplex-Doppler US is the most accurate diagnostic method for the evaluation of neck vessels. It yields morphologic information on the vessels--diameter, course and wall--and hemodynamic information on direction, velocity and characteristics of flow. In the detection of stenosis and occlusion of the carotid artery, US diagnostic accuracy, both as reported in literature and as observed in our personal series, is very high. On the other hand, US diagnostic accuracy is lower in the vertebral artery, because of the difficulties in studying the artery origin. The comparison of duplex US and angiographic results suggests the need of using both techniques, especially in the study of the patients to submit to surgery.
The ultrasound (US) findings in 20 patients with 23 carotid-body chemodectomas were reviewed. Twenty-two of 23 tumors could be seen at US; the remaining lesion could not be differentiated from surrounding enlarged lymph nodes resulting from thyroid cancer. The lesions were solid, slightly heterogeneous masses that ranged in size from 1.2 to 5.0 cm and were located within the carotid bifurcation. Pulsed Doppler analysis of blood flow within the tumor mass was possible in eight patients with nine chemodectomas, and low-resistance waveforms were obtained from multiple sites within the mass in all cases. The diagnostic possibility of a chemodectoma has to be considered when a solid mass is detected within the carotid bifurcation. On the basis of these findings, as US diagnosis was possible in 18 of 20 patients in the authors' series. Doppler analysis of the mass to evaluate intratumor blood flow is helpful in differentiating chemodectomas from other solid, nonhypervascular masses.
Six hundred and sixty-seven hypertensive patients were analyzed by captopril-enhanced scintigraphy. If time to reach maximal activity (Tmax) was > or = 5 min using 99mTc-diethylenetriaminepentaacetic acid (DTPA) or > or = 3 min with 123I-o-iodohippurate (OIH) and 99mTc-mercaptoacetyltriglycine (MAG3) and washout time > or = 15 min, a control study with nifedipine was performed. If the difference between Tmax under captopril and nifedipine premedication was > or = 5 min with 99mTc-DTPA or > or = 3 min with 123I-OIH and 99mTc-MAG3, the renogram was defined highly suggestive of renovascular hypertension. In the evaluation of bilateral abnormalities an additional parameter was considered, i.e. the presence of functional asymmetry of the emuntories susceptible of partial reversal in the control study under nifedipine. Based on these criteria, 58 out of 667 (8.7%) scintigrams were found to be abnormal. Thirty-five of these 58 patients and 32 of the remaining 609 scintigraphically negative cases underwent additional arteriographic examination. A renal vascular stenosis > or = 50% was found in 33 out of 35 (94.2%) patients with positive scintigraphy and in 3 out of 32 patients with negative scintigraphy. By examining results of the 67 patients undergoing arteriography, the sensitivity of captopril-enhanced scintigraphy was estimated to be 91.6%, with a specificity of 93.5%, an accuracy of 92.5%, and predictive values of a positive or negative result of 94.2 and 90.6%, respectively. By restricting analysis to bilateral stenosis, sensitivity was found to be 76.9%.(ABSTRACT TRUNCATED AT 250 WORDS)
The use of MRT in craniofacial pathology has been evaluated above all as regards the possibility offered by this technique for studying the soft parts with better results than already sophisticated investigations like the CT scan. The technique's limitations are the long duration of the investigation, the impossibility of carrying it out in carriers of pacemakers, the inadequate visualisation of the bone and calcifications, the fairly high cost; the advantages are the fact that ionising radiation is not employed, the ureter sensitivity for the soft parts, the good vessel evaluation and the possibility of obtaining oriented sections in every space plane without moving the patient. The use of MRT is therefore rich in prospects.
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We assessed the accuracy of criteria for diagnosing an inferior myocardial infarction from body potential maps. Body surface potential maps were recorded from 140 lead points on the entire chest surface in three groups of subjects: group A consisted of 15 patients with an old inferior myocardial infarction and typical electrocardiographic signs of necrosis; group B consisted of 15 patients with an old inferior myocardial infarction, but without electrocardiographic signs of necrosis (inferior myocardial infarction was documented during the acute phase); group C consisted of 30 healthy controls. In each subject body surface potential distributions were examined every 2 msec of the QRS complex. Moreover, the potential-time integrals relating to three intervals (QRS, the first 20 and the first 40 msec of the QRS complex) were calculated at each lead point and transferred to diagrams representing the thoracic surface explored (isointegral maps). For each time interval, the mean isointegral map obtained from group C subjects was subtracted from the isointegral map of each patient. The value obtained at each lead point was then divided by the standard deviation of the normal values for that point; the resulting values indicating the standardized differences from normal values were transferred to another map (deviation index isointegral map, DI map). We considered a reliable index of inferior myocardial infarction an area where the time-integral values were at least 2 SD lower than normal, in the inferior half of the thorax. A number of variables relative to instantaneous potential distribution and to isointegral maps were considered. The DI maps of the first 40 msec of QRS gave the most accurate criteria; in fact, an area of negative values 2 SD lower than normal was found in all group A patients and in 11 out of 15 group B patients (sensitivity 100% in group A, 73% in group B and specificity, 83%). Thus our results indicate that body surface potential maps have greater diagnostic information content than the 12 standard electrocardiographic leads and demonstrate the usefulness of the time integral analysis of body surface potentials for diagnostic interpretation.
Cervicocephalic chemodectomas are rare non-chromaffin paraganglionic tumours, most often originating in the carotid body or the jugular ganglion. Their main features are a reluctance to invade adjacent tissue and the absence of general clinical signs. Since they are histologically quite varied they may at times be difficult to recognise. A chemodectoma of a hitherto unreported type is described. Encountered in the pterygo-maxillary fossa it was identified by computerised axial tomography and angiography.
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To evaluate the feasibility of percutaneous treatment of iliac aneurysms, a covered stent was inserted in nine men suffering from common iliac artery aneurysms (six cases), external iliac aneurysms (one case), or pseudoaneurysms (two cases). Placement of the stent was successful in all patients. In one patient, an endoprosthesis thrombosed after 15 days, but was successfully treated by thrombolysis and additional stent placement. At the follow-up examinations (mean period 22 months) all stent-grafts had remained patent. No late leakage or stenosis was observed.
PURPOSE: To assess, in a multicenter setting, safety, technical results, and restenosis rate of the Palmaz stent for treatment of atherosclerotic ostial renal artery stenosis. METHODS: Ten centers enrolled 106 patients (120 treated renal artery stenoses) in the study. Patient selection was based on unsuccessful percutaneous transluminal renal angioplasty (residual stenosis >/= 20%) performed for treatment of ostial stenosis >/= 50%, in patients with hypertension and/or impaired renal function. Safety was assessed by means of the complication rate, and technical results by the number of successful stent placements and occurrence of restenosis (>50%) at intraarterial angiographic follow-up. RESULTS: Stent placement was successful (n = 112) or partially successful (n = 5) in 117 (98%) arteries. Complications occurred in 19 procedures; seven were of serious clinical significance. Angiographic follow-up was performed in 89 of 117 (76%) cases, at a mean of 8 months (range 2. 5-18 months). Fifteen stents (16.9%) showed restenosis (at a mean of 8.5 months), of which 10 were successfully redilated. CONCLUSION: Renal artery stenting has a high technical success rate, a complication rate comparable to percutaneous transluminal renal angioplasty, and a low rate of restenosis at 8 months angiographic follow-up.
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PURPOSE: To verify the suitability of indicative quantities to evaluate the risk related to patient exposure, in abdominal and vascular interventional radiology, by the study of correlations between dosimetric quantities and other indicators. MATERIAL AND METHODS: We performed in vivo measurements of entrance skin dose (ESD) and dose area product (DAP) during 48 procedures to evaluate the correlation among dosimetric quantities, and an estimation of spatial distribution of exposure and effective dose (E). To measure DAP we used a transmission ionization chamber and to evaluate ESD and its spatial distribution we used radiographic film packed in a single envelope and placed near the patient's skin. E was estimated by a calculation software using data from film digitalisation. RESULTS: From the data derived for measurements in 27 interventional procedures on 48 patients we obtained a DAP to E conversion factor of 0.15 mSv / Gy cm2, with an excellent correlation (r=.99). We also found a good correlation between DAP and exposure parameters such as fluoroscopy time and number of images. The greatest effective dose was evaluated for a multiple procedure in the hepatic region, with a DAP value of 425 Gy cm2. The greatest ESD was about 550 mGy. For groups of patients undergoing similar interventional procedures the correlation between ESD and DAP had conversion factors from 6 to 12 mGy Gy-1 cm-2. CONCLUSION: The evaluation of ESD and E by slow films represents a valid method for patient dosimetry in interventional radiology. The good correlation between DAP and fluoroscopy time and number of images confirm the suitability of these indicators as basic dosimetric information. All the ESD values found are lower than threshold doses for deterministic effects.
Doppler sonography is nowadays considered as a "first step" tool for diagnosis of vascular complications in kidney transplantation. Quite recently, it has been sometimes considered useful and effective investigation in order to obtain information about parenchymal dysfunctional pathologies, particularly about acute rejection. This has been obtained by studying the variation of resistive indexes. The goal of the following investigation was compare Doppler sonography data and histological examination in 50 kidney transplanted recipients in whom the renal biopsy was performed on a clinical basis. In the Authors' experience. Doppler sonography and study of the resistive index does not offer any reliable help in differentiating acute rejection from cyclosporine A toxicity.
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