Biomedical subjects

Carlo Bartolozzi

Publications and source records attributed to Carlo Bartolozzi.

41 records · Page 3Linked to original sources

PubMed2001

Tissue harmonic and contrast-specific imaging: back to gray scale in ultrasound.

The development of new US techniques that produce images based on nonlinear acoustic effects of US interaction with matter or microbubble contrast agents has opened new prospects for gray-scale US in native tissue and contrast imaging. Tissue harmonic imaging uses higher frequencies generated on propagation of the US beam through matter to improve image quality and resolve small anatomic structures and details, and is becoming a routine approach in US examination of many abdominal districts. Contrast-specific imaging techniques display enhancement of US agents in gray-scale with optimal contrast and spatial resolution, and offer high sensitivity either to microbubble movement or to microbubble destruction in dependence of the level of the applied acoustic peak pressure. Owing to the ability to exploit the microcirculation, contrast-specific techniques have enabled the evolution of contrast US from vascular imaging to the imaging of perfused tissues. Several studies have shown that these methods can substantially improve US detection and characterization of focal liver lesions, and promising results have been reported in other areas of investigation. This article reviews physical principles, technical issues, and clinical applications of tissue harmonic and contrast-specific imaging. It is foreseen that the new gray-scale US techniques will rapidly become a tool in numerous clinical scenarios.

Carcinoma, Hepatocellular↗

PubMed1999

Contrast-Enhanced Doppler Ultrasound of Renal Artery Stenosis: Prologue to a Promising Future.

Over the past few years, there has been extensive research for a reliable, noninvasive, and nonionizing imaging method to screen for renal artery stenosis (RAS). Doppler ultrasound (US) is one of many modalities that have been evaluated for the detection of RAS. The lack of standardization in examination protocols and diagnostic criteria, as well as the wide differences in reported accuracy among different laboratories, however, have prevented universal acceptance of this technique as a reliable screening test for RAS. Recently, the introduction of US contrast agents has substantially expanded the potentials of color Doppler US. The use of microbubble echo enhancers in combination with harmonic Doppler imaging has been shown to improve diagnostic confidence by improving the operator's ability to visualize the renal arteries, and to significantly reduce the number of equivocal examinations. In addition, contrast-enhanced harmonic Doppler US can currently provide objective functional assessment of RAS through analysis of time-intensity renal enhancement curve. State-of-the-art contrast-enhanced Doppler US seems to have the potential to become a useful screening test for patients at risk from renovascular hypertension and a tool for follow-up of patients who undergo revascularization procedures.

Journal Article↗

PubMedDate not supplied

Predictive factors of in-stent restenosis in renal artery stenting: a retrospective analysis.

PURPOSE: To retrospectively evaluate the role of clinical and procedural factors in predicting in-stent restenosis in patients with renovascular disease treated by renal artery stenting. METHODS: From 1995 to 2002, 147 patients underwent renal artery stenting for the treatment of significant ostial atherosclerotic stenosis. Patients underwent strict clinical and color-coded duplex ultrasound follow-up. Ninety-nine patients (111 stents), with over 6 months of continuous follow-up (mean 22+/-12 months, range 6-60 months), were selected and classified according to the presence (group A, 30 patients, 32 lesions) or absence (group B, 69 patients, 79 lesions) of significant in-stent restenosis. A statistical analysis was performed to identify possible preprocedural and procedural predictors of restenosis considering the following data: sex, age, smoking habit, diabetes mellitus, hypertension, serum creatinine, cholesterol and triglyceride levels, renal artery stenosis grade, and stent type, length and diameter. RESULTS: Comparing group A and B patients (chi(2) test), a statistically significant relation was demonstrated between stent diameter and length and restenosis: the risk of in-stent restenosis decreased when the stent was >/=6 mm in diameter and between 15 and 20 mm in length. This finding was confirmed by multiple logistic regression analysis. Stent diameter and length were proved to be significantly related to in-stent restenosis also when evaluating only patients treated by Palmaz stent (71 stents). CONCLUSION: Although it is based on a retrospective analysis, the present study confirms the importance of correct stent selection in increasing long-term patency, using stents of at least 6 mm in diameter and with a length of approximately 15-20 mm.

Adult↗

PubMedDate not supplied

Endovascular repair of abdominal aortic aneurysms: analysis of aneurysm volumetric changes at mid-term follow-up.

PURPOSE: To evaluate the volumetric changes in abdominal aortic aneurysms (AAA) after endovascular AAA repair (EVAR) in 24 months of follow-up. METHODS: We evaluated the volume modifications in 63 consecutive patients after EVAR. All patients underwent strict duplex ultrasound and computed tomography angiography (CTA) follow-up; when complications were suspected, digital subtraction angiography was also performed. CTA datasets at 1, 6, 12, and 24 months were post-processed through semiautomatic segmentation, to isolate the aneurysmal sac and calculate its volume. Maximum transverse diameters (Dmax) were also obtained in the true axial plane, Presence and type of endoleak (EL) were recorded. A statistical analysis was performed to assess the degree of volume change, correlation with diameter modifications, and significance of the volume increase with respect to ELs. RESULTS: Mean reconstruction time was 7 min. Mean volume reduction rates were 6.5%, 8%, and 9.6% at 6, 12, and 24 months follow-up, respectively. Mean Dmax reduction rates were 4.2%, 6.7%, and 12%; correlation with volumes was poor (r = 0.73-0.81). ELs were found in 19 patients and were more frequent (p = 0.04) in patients with higher preprocedural Dmax, The accuracies of volume changes in predicting ELs ranged between 74.6% and 84.1% and were higher than those of Dmax modifications. The strongest independent predictor of EL was a volume change at 6 months < or = 0.3% (p = 0.005), although 6 of 19 (32%) patients with EL showed no significant AAA enlargement, whereas in 6 of 44 (14%) patients without EL the aneurysm enlarged. CONCLUSION: The lack of volume decrease in the aneurysm of at least 0.3% at 6 months follow-up indicates the need for closer surveillance, and has a higher predictive accuracy for an endoleak than Dmax.

Aged↗

PubMedDate not supplied

Differentiation of benign and malignant breast microcalcifications: mammography versus mammography-sonography combination.

PURPOSE: The aim of this study was to determine the diagnostic contribution of high-frequency sonography in the diagnosis of isolated clustered microcalcifications detected by mammography. MATERIAL AND METHODS: 238 women (aged 3198) with isolated clustered microcalcifications were examined by mammography and subsequently by high frequency sonography (13 MHz) at the site of microcalcification. 170 underwent surgery. 94 were affected by cancer and 76 by benign pathology. The other 68 were considered to have benign microcalcifications after three years follow-up. The ROC statistical technique was employed to compare the diagnostic role of mammography alone versus the combination of mammography and sonography. The area under the ROC curves was calculated by the Wilcoxon method, without any hypothesis on the distribution of the statistical data. RESULTS: The microcalcifications were neoplastic in 39.5% of cases. The difference between the areas under the mammography ROC curve (area = 0.807, standard error = 0.03) and the mammography-sonography ROC curve (area = 0.819, standard error = 0.028) was not statistically significant (p > 0.05). CONCLUSIONS: The higher sensitivity of mammography-sonography combination demonstrates that it may be useful to perform sonography following mammography when mammography yields a diagnosis of non malignant pathology.

Adult↗