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F Pozzi Mucelli

Publications and source records attributed to F Pozzi Mucelli.

14 recordsLinked to original sources
PubMed1996

Three-dimensional reconstructions of carotid bifurcation from CT images: evaluation of different rendering methods.

Three-dimensional computed tomographic angiography (3D-CTA) and digital subtraction angiography of the cervical carotid artery were performed bilaterally in 15 patients with suspected stenoses. A new semi-automatic segmentation and new rendering methods were used. The degree of stenosis of internal carotid arteries, as determined both by axial slices and 3D images (surface, integral, maximum-intensity-projection, and raysum-rendered images), was compared qualitatively and quantitatively to angiographic findings. In correlation to angiography, the accuracy in determining the stenosis classification of internal carotid arteries was of 97% for axial slices and 59-90% for 3D images, respectively. Raysum (pseudoradiograph) rendering was found to be the most reliable rendering method and gave the most similar results to angiography. The accuracy of all rendering methods was improved by applying calcification removing algorithm, with a statistically significant difference between surface rendering without plaque removal and raysum rendering using the removing algorithm.

Adult↗
PubMed1996

"Aggressive" renal angiomyolipoma.

PURPOSE: We describe the US and CT examinations of 4 patients with renal angiomyolipoma with an "aggressive" appearance, and review the literature. MATERIAL AND METHODS: The imaging findings in 4 patients with benign renal angiomyolipomas associated with thrombosis of the renal vein and/or inferior vena cava are presented. In one case, enlarged lymph nodes at the renal hilum were found. RESULTS: CT demonstrated fat densities within both tumor and thrombus. In one patient, small lymph nodes with low density internal areas were detected in the para-aortic region. When considering our patients together with those reported in the literature, we found that most angiomyolipomas with venous invasion were large and centrally located within the kidney. Venous thrombosis was observed in 9 lesions of the right kidney, and in only 4 of the left one; detection of the site of origin was impossible in one case. One patient only had symptoms due to the thrombus; 10 had problems due to the tumor; and 3 were asymptomatic. Only 4 patients with pararenal enlarged lymph nodes have been reported on in the imaging literature. Fat-containing nodes were detected by CT in one case only; the others had enlarged nodes of soft-tissue density. In one patient the diagnosis of hamartomatous lymph node invasion was established by angiography. CONCLUSION: In patients with renal angiomyolipoma, demonstration of both fatty thrombus and the fatty infiltration of lymph nodes of the renal hilum cannot be regarded as an indication of malignancy, but only of local aggressive behavior. Although surgery is commonly contemplated to prevent symptoms from venous thrombosis, conservative treatment seems possible. Detection of enlarged lymph nodes of soft tissue density may cause difficult diagnostic problems, with the diagnosis addressed only by the presence of associated lesions. Increased awareness that renal angiomyolipoma can sometimes appear "aggressive" could help to prevent such lesions from being considered malignant, and thus avoid surgical confirmation of their nature.

Adult↗
PubMed1995

[Optimization of scanning and processing parameters for the three-dimensional reconstruction in computerized tomography of the facial bones].

The evolution of computer technology has significantly improved the performances of three-dimensional reconstructions from Computed Tomographic images. The authors discuss the examination technique and the modalities of three-dimensional reconstruction based upon a new advanced workstation. This unit is based on a Sun Sparkstation linked with the main computer of the CT scanner. The workstation is extremely fast, the processing time for a high resolution three-dimensional image of the maxillofacial region being about 3 minutes. The scanning parameters, image reconstruction and visualization were investigated on cases of maxillofacial (mainly posttraumatic) conditions. The most important scanning parameters are slice thickness, table incrementation, dose, scan plane. Slice thickness and table incrementation are the parameters bearing the greatest influence on the quality of the three-dimensional images. Dose is also important but bears no influence on image quality: therefore it can be kept as low as possible to reduce patient exposure. The scanning plane has some minor effect; coronal images have some advantages over axial images but in many cases only axial images can be acquired. The reconstruction parameters are the threshold and the matrix. The threshold may range 70 to 300 HU but in most cases ranges 120 to 200 HU. An advantage offered by this system is that it allows threshold values to be changed after the reconstruction has been completed, without performing a new reconstruction. The visualization parameters include four rendering methods, i.e. the surface mode, the integral mode, the maximum intensity projection and the ray sum. The surface mode is the one yielding the best results for bones while the others are used for the reconstruction of soft tissues and vessels. The workstation enables the three-dimensional images to be processed with shading parameters, and to be modified with cut planes, disarticulation methods and other interactive methods.

Bone Diseases↗
PubMed1995

[Tridimensional reconstructions of intra- and extracranial arteries using computerized tomography].

Three-dimensional Computed Tomographic Angiography (3D CTA) is a new imaging technique for vascular structures. This study was aimed at investigating the diagnostic role of 3D CTA in the intracranial and extracranial arteries. Fifteen patients with intracranial artery disease (thirteen with aneurysms and two with arteriovenous malformations) and fifteen patients with stenosis of the common, internal or external carotid arteries underwent 3D CTA. All patients had been examined with intraarterial angiography. The CT examinations were performed with dynamic scanning during intravenous contrast agent administration. Three-millimeter thick contiguous slices were obtained in the cervical region and 1.5-mm contiguous slices in the intracranial region. CT findings were processed to produce 3D views on an independent workstation. 3D CTA results were compared with those of intraarterial DSA in all cases. Agreement was found in 13 of 15 cases of intracranial vascular abnormalities, and in 26 of the 30 carotid arteries in classifying the severity of the stenosis. The 3D views, which exhibit an excellent image quality, seem to be comparable to angiography in the intracranial and extracranial arteries. The main advantages of this technique are: 1) its low invasivity since only an intravenous contrast agent injection is required; 2) its easy and fast acquisition (2-3 minutes are needed if a non-spiral CT unit is used and less than one minute with spiral CT); 3) good demonstration of the calcified plaques which can be also removed with the softwares available at the workstation, to show the overall vessel lumen; 4) thanks to its simplicity the examination can also be performed in emergency (i.e. in patients with subarachnoid hemorrhage, if plain CT is positive for subarachnoid bleeding). Its main limitations are: 1) the need of an adequate concentration of contrast agent in the vessels; 2) artifacts due to calcified and bone structures; 3) no information about vessel inflow; 4) limited discrimination between arteries and veins in some areas (cavernous sinus); 5) limited field of view compared to angiography.

Carotid Arteries↗
PubMed1994

[Thin-section computerized tomography of the kidney in the differential diagnosis of small tumor and cystic hypodensities].

Small hypodense renal lesions with a round shape are frequently detected on CT scans of the upper abdomen after contrast medium administration. In nearly all cases these round hypodensities are simple small cysts with no clinical significance. However, the fluid density of these cysts cannot be always defined, due to the partial volume averaging which occurs on CT when 10-mm-thick slices and contrast enhancement are used. Therefore, a malignant tumor--i.e., small renal tumors or metastatic lesions--cannot be ruled out in some cases. Since the limitations of CT are related to partial volume averaging, the authors used both 5-mm and 10-mm slices to reduce this artifact. Forty-eight small hypodensities (< 15 mm) were studied after contrast agent administration: 42 of them were simple cysts and 5 were tumoral lesions--i.e., 3 renal cell carcinomas and 2 lymphomatous lesions. The results showed that, with 5-mm slices, the density of the fluid hypodensities decreased in nearly all cases and in 81.3% of cases it was below 30 HU. The difference in densities between 10-mm and 5-mm slices was about 50 HU (75 +/- 30 to 21 +/- 16 HU). In the 5 tumoral hypodensities, lesion density was still in the soft tissue range also with 5-mm slices, with no major decrease. These results show that this technique is simple and effective in the differential diagnosis of small renal hypodensities since it requires only a short additional examination time.

Adult↗
PubMed1993

[Arterial anatomy of the celiac trunk and the superior mesenteric artery with computerized tomography].

A hundred patients with different conditions underwent CT and the results were retrospectively reviewed to evaluate the visibility of the celiac trunk, of its branches and of the superior mesenteric artery. Thirty-six patients underwent angiography too, which allowed the anatomical variants suspected on CT to be demonstrated, according to Kuhns' criteria. The other 64 patients were consecutively selected and only aneurysmal changes were not included. All examinations were performed using a General Electric 9800 Advantage scanner, with 2 second scanning time and 10 mm-thick contiguous scans. In 20 patients 5 mm contiguous scans were performed. All examinations followed i.v. injections of contrast agents which were given with an automatic injector. The cases with suspected anatomical variants on CT but with no angiographic confirmation were not considered. A hundred CT exams were retrospectively reviewed: the celiac trunk and the common hepatic artery were demonstrated in all of them. Visibility of the other branches was 40% for the hepatic artery, 53% for the right branch of the hepatic artery and 39% for its left branch, 70% for the gastroduodenal artery, 82% for the left gastric artery, 97% for the splenic artery and 100% for the superior mesenteric artery. As for the 36 patients who underwent both CT and angiography, right hepatic artery from the superior mesenteric artery was seen in 19% of cases with both modalities; common hepatic artery arising from the superior mesenteric artery was detected in 2% of cases. In both instances, these anatomical variants appeared as a vessel running posterior to the portal vein. The careful investigation of axial CT scans showed the level of origin of the artery from the superior mesenteric artery. These results are in agreement with the angiographic data reported in the literature. Our study demonstrated that the celiac trunk and its variants are always depicted by the new CT scanner. The knowledge of these variants may be useful in the patients to submit to liver surgery. The celiac trunk and its variants are demonstrated with conventional 10 mm slices. The use of 5 mm slices improves the visibility of thin anatomical branches but is not essential to recognize the major vessels and anatomical variants.

Celiac Artery↗
PubMed1991

[Computerized tomography: problems and errors in the diagnosis of renal masses].

The diagnostic imaging of renal masses has greatly benefitted from US and CT. Nevertheless, a certain number of problems and errors are still present, and they must be discussed once more. In the authors' experience, problems and errors have 3 fundamental causes: operator, examination technique and complex patterns of renal masses. The latter is the most important cause of error in CT diagnosis. Complex patterns are seen in a limited number of cystic masses--i.e., hemorrhagic, inflammatory, and septated cysts, and cystic tumors. Hemorrhagic cysts, if hemorrhage is not recent, can cause some diagnostic difficulties since the typical high density of the recent hemorrhage is no longer present. Other renal masses may appear hyperdense on unenhanced CT scans, and therefore they must be considered in the differential diagnosis. Inflammatory cysts and abscesses are sometimes difficult to differentiate from other masses due to their aspecific appearance; clinical correlation is important in these instances to support CT diagnosis. Multiseptated cysts and cystic tumors cause huge problems of differential diagnosis. A good knowledge of differential CT findings is sure to reduce the problems in differentiating benign from malignant tumors and, among the latter, the different histotypes and metastases, when present as solitary masses. Also in this case, the correlation between CT, clinical history and other modalities can reduce the number of questionable cases.

Diagnostic Errors↗
PubMed1988

[Computerized tomography of the spine in the evaluation of multiple myeloma].

Computed Tomography (CT) of the spine was performed on 17 patients with myeloma in order to assess the role of the technique in recognizing and evaluating the extent of the lesions. Myelomatous lesions followed two patterns at CT: first of all, multiple focal lesions, whose density is either solid, liquid, or fatty; second, an extensive pattern involving the spongiosa of the vertebra, including the posterior arch. CT detected more lesions than conventional radiology; furthermore, the extent of the lesions was much better demonstrated by CT. CT should thus be performed: a) in case of pain and/or neurological findings in negative radiological examinations; b) to evaluate the extent of myelomatous lesions (mainly in the spine); c) in solitary myeloma CT may be performed on different bone segments with clinical symptomatology but normal X-ray findings.

Humans↗
PubMed1986

[3-dimensional craniofacial computerized tomography].

Computed tomography allows today to reconstruct three-dimensional (3D) images from axial scans. The authors report their experience in cranio-facial pathology achieved in two Departments of Radiology (University of Trieste, Italy and University of Stanford, California). 3D images have been realized using two different softwares, one of which allows to reconstruct both soft tissue and bone structures. The applications in maxillo-facial traumas, cranio-facial malformations and head tumours are discussed. 3D images turned out to be very useful for the optimal visualization and for the spatial demonstration of the lesion and have potential applications in cranio-facial surgery and radiotherapy.

Facial Bones↗
PubMed1986

Three-dimensional computed tomography of the acetabulum.

Acetabular fractures represent a complex variety that are classified in different types. Conventional radiology is often inadequate to demonstrate and classify the fractures. Computed tomography (CT) has already been shown to be superior in this field. A further advantage of CT is represented by the recent availability of three-dimensional (3D) images that are realized from axial CT scans by means of a new software. The Authors report the applications of this new software to the study of the normal acetabulum and in patients with fractures. 3D images allows an effective demonstration of the fracture, its irradiation and the dislocation of bone fragments. The information is contained in one or few images rather than many axial images. Therefore the role of 3D images may be considered complementary to axial CT scans.

Acetabulum↗
PubMed1985

Computed tomographic follow-up in a case of Addison's disease.

Addison's disease of the adrenal glands presents with different pathological findings depending on the stage. In the acute phase the adrenal glands are bilaterally enlarged while in the chronic phase the glands are small and calcified. A case of Addison's disease with follow-up over a period of a year by CT is reported. CT showed the evolution of the adrenal glands from bilateral masses to small calcified glands. The differential diagnostic problems in the acute phase are also discussed.

Addison Disease↗
PubMed1985

[Computed tomography of the femur head. Normal aspects and appearance in aseptic necrosis].

The diagnostic value of Computed Tomography (CT) in the diagnosis of the aseptic necrosis of the femoral head is discussed. The CT findings in the different evolutive stages are reported and the respective diagnostic value of Conventional Radiology and CT are discussed. The CT findings of femoral head necrosis in the early phases are emphasized. The capability of CT to demonstrate structural changes in femoral heads with regular morphology allows to consider this technique when there exists a clinical doubt of osteonecrosis of the femoral head and in risk patients.

Adult↗
PubMed1985

[Adrenal tuberculosis in 13 patients with Addison's disease. CT findings].

A series of thirteen cases of adrenal tuberculosis with Addison's disease is presented. At the onset of disease, CT findings consisted of an enlargement of both glands, with peripheral enhancement after contrast medium was injected. The CT differential diagnosis among tubercular, metastatic and amyloidotic etiology was not possible. When the course of the illness was favourable, CT showed a generalized glandular atrophy with calcifications. In two fatal cases, the diagnosis could be made only at post-mortem examination.

Addison Disease↗