Biomedical subjects

D Caramella

Publications and source records attributed to D Caramella.

At least 55 records · Page 3Linked to original sources

PubMed1996

Comparison among sonography, double-tracer subtraction scintigraphy, and double-phase scintigraphy in the detection of parathyroid lesions.

OBJECTIVE: This study prospectively evaluated the sensitivity of high-resolution sonography compared with double-tracer 201Tl-99mTc scintigraphy (Tl-Tc) subtractive scintigraphy and double-phase 99mTc-sestamibi (Tc-MIBI) scintigraphy prior to surgery in the assessment of patients with primary hyperparathyroidism in a geographic region where areas of endemic thyroid goiter are present. SUBJECTS AND METHODS: Sonography and scintigraphy were used as first-step imaging procedures in 73 patients with primary hyperparathyroidism. In 30 (41%) of 73 cases, we found an association with a thyroid abnormality. We compared sonography with double-tracer Tl-Tc scintigraphy in 41 cases, with Tc-MIBI scintigraphy in 22 other cases, and with both scintigraphic studies in 10 other cases. RESULTS: Surgery demonstrated 68 solitary parathyroid lesions (66 adenomas, one hyperplasia, and one carcinoma), two adenomas in two patients, and multiple hyperplastic glands in two patients for a total of seven lesions. In one case no abnormal parathyroid gland was found. Overall sensitivity of sonography, Tl-Tc, and Tc-MIBI scintigraphy was 85%, 62%, and 82%, respectively. In patients with concomitant thyroid disease, the sensitivity of sonography, dual-tracer Tl-Tc, and Tc-MIBI was 77%, 67%, and 80%, respectively. CONCLUSION: Our study proves that sonography and scintigraphy are equally able to detect parathyroid lesions before surgery in patients with concomitant thyroid diseases. In patients without thyroid abnormalities, detection rates of sonography and Tc-MIBI do not show any statistical difference, and the detection rate of Tl-Tc is significantly inferior to that of sonography. Sonography alone should be used as the first step for localization of abnormal parathyroid glands prior to surgery, and Tc-MIBI scintigraphy should be used as the second step when sonography is negative.

Adolescent↗

PubMed1996

[Implementation of a server World Wide Web of radiology accessible by Internet].

Internet is an international computer network that uses standard communication protocols for the exchange of information. This facilitates the retrieval of multimedia data through a "web" of servers distributed in the whole world. Among Internet users, Radiologists are a potentially important segment, due to the inherent multimedia characteristics of the discipline, which requires a continuous international update of information. The Department of Radiology of the University of Pisa has an Internet access through the metropolitan area network which was installed in the framework of the CNR Telecomunicazioni Project. The Internet access allowed the implementation of a World Wide Web server made public on Internet in March, 1994, being the first European server specifically oriented to radiology. This server can be accessed at the following address: http:@www.rad.unipi.it:7080/IRMosaicHome.html . On the server, 3 hypermedia papers are present, a list of international servers containing radiological information, a questionnaire, and statistics concerning the number of users who accessed the server. In the first 18 months of public access through Internet (April 1, 1994-September 30, 1995) 16,166 users accessed the server, retrieving 127,349 documents, corresponding to 1,279.7 MByte of information. The mean amount of information retrieved in each access to the server in the considered quarters ranges from 72 to 85.8 kByte. The geographic distribution of the users who accessed the server is the following: United States, 7,158, Italy, 2,466; other European countries, 3,813; other extra-European countries, 2,729. The increasingly diffuse knowledge of Internet services had a substantial impact on the rise in number of the servers and of the users who can access them. It is likely that in the future this technology will be used with increasing interest by Radiologists, since it provides easier "navigation" through multimedia information, consisting of text and several images, without the inherent limitations of the printed paper.

Computer Communication Networks↗

PubMed1995

Treatment of small hepatocellular carcinoma with percutaneous ethanol injection. Analysis of prognostic factors in 105 Western patients.

BACKGROUND: Percutaneous ethanol injection (PEI) has been used in the Far East for treating small, unresectable hepatocellular carcinoma (HCC). To clarify when treatment with PEI may be best indicated for Western patients with HCC, the authors performed a retrospective analysis of the clinicopathologic factors influencing prognosis. METHODS: From December 1987 to August 1994, 105 patients with cirrhosis with HCC received PEI as the sole anticancer treatment. Eighty-two patients had uninodular tumors smaller than 5 cm, and 23 patients had multiple lesions (2-4) smaller than or equal to 3 cm each. All patients were in Child-Pugh class A (n = 64) or B (n = 41). Survival was analyzed according to patient- and tumor-related factors by means of the Kaplan-Meier method. RESULTS: The estimated survival rates of all 105 patients were 96% at 1 year, 86% at 2 years, 68% at 3 years, 51% at 4 years, 32% at 5 years, and 24% at 6 years. Survival was not affected by sex, age, etiology of cirrhosis, or hepatitis B surface antigen or anti-hepatitis C virus positivity, but depended on Child-Pugh class (P = 0.006) and presence of ascites (P = 0.009). Patients with a pretreatment alpha-fetoprotein level of 200 ng/ml or less had a better prognosis than patients with an alpha-fetoprotein level higher than 200 ng/ml (P = 0.007). Patients with unmodular HCC of 3 cm or less had significantly better long term survival (P = 0.04) than patients with uninodular HCC of 3.1-5 cm or with multinodular tumors. Tumor grade according to Edmondson and Steiner and tumor volume, in contrast, did not significantly influence prognosis (P > 0.1). CONCLUSIONS: For Western patients with HCC treated with PEI, the prognosis was highly dependent on the severity of the underlying cirrhosis. Treatment with PEI is best indicated for patients with uninodular tumors of 3 cm or less in greatest dimension and an alpha-fetoprotein level lower than 200 ng/ml.

Administration, Cutaneous↗

PubMed1995

Hepatocellular carcinoma: use of color Doppler US to evaluate response to treatment with percutaneous ethanol injection.

PURPOSE: To determine the usefulness of color Doppler ultrasound (US) in the evaluation of the response of hepatocellular carcinoma (HCC) to percutaneous ethanol injection (PEI). MATERIALS AND METHODS: Forty-one patients with 48 lesions 2-5 cm in diameter underwent color Doppler US before and after PEI. Computed tomography (CT), magnetic resonance (MR) imaging, and percutaneous biopsy were also performed to help establish the outcome of therapy. RESULTS: Before treatment, color signals with an arterial Doppler spectrum were seen in 44 of 48 lesions with a frequency shift of 0.51-4.11 kHz (mean, 1.65 kHz). After PEI, 37 of these lesions showed no color signal and were found to be necrotic at CT, MR imaging, and biopsy. In six of seven lesions containing residual tumor, pulsatile flow was still identified, although the frequency shift was significantly decreased (P = .01). CONCLUSION: Color Doppler US proved useful in the assessment of the therapeutic effect of PEI on HCC.

Aged↗

PubMed1995

Treatment of large HCC: transcatheter arterial chemoembolization combined with percutaneous ethanol injection versus repeated transcatheter arterial chemoembolization.

PURPOSE: To compare the efficacy of transcatheter arterial chemoembolization (TACE) combined with percutaneous ethanol injection (PEI) versus repeated TACE in the treatment of large hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Fifty-three patients with cirrhosis and a large HCC (main tumor, 3.1-8.0 cm in diameter with no more than two daughter nodules) were enrolled in a prospective, randomized study. Twenty-six patients underwent a single TACE session followed by PEI (TACE-PEI group), whereas 27 patients underwent two to five TACE sessions (TACE group). Both groups of patients were similar with regard to liver function. Follow-up ranged from 8 to 39 months. RESULTS: Complete therapeutic responses were higher (P < .05) and tumor recurrences during follow-up were lower (P < .05) in the TACE-PEI group than in the TACE group. Patients in the TACE-PEI group survived longer than those in the TACE group, although the difference was not significant (P > .1). The rates of survival without recurrence were better in the TACE-PEI group than in the TACE group (P < .05). CONCLUSION: Use of a single TACE session combined with PEI is more effective than repeated TACE in the treatment of large HCC.

Aged↗

PubMed1995

Portal vein thrombosis after percutaneous ethanol injection for hepatocellular carcinoma: value of color Doppler sonography in distinguishing chemical and tumor thrombi.

OBJECTIVE: The distinction between benign (chemical) and tumor thromboses of the portal vein after treat,ent with percutaneous injection of ethanol for hepatocellular carcinoma is crucial for the proper management of the patient. The purpose of this study was to determine whether color Doppler sonography can be used to differentiate between the two types of thrombi. SUBJECTS AND METHODS: Between October 1991 and April 1994, portal vein thrombosis was detected by color Doppler sonography in 19 patients (13 men and six women 59-77 years old; mean age, 67 years) who had hepatocellular carcinomas and who had received percutaneous ethanol injection (n = 11) or percutaneous ethanol injection after transcatheter arterial embolization (n = 8). The criterion for diagnosing tumor thrombosis by color Doppler sonography was the detection of pulsatile arterial flow in the thrombus. The benign or malignant nature of the thrombosis was subsequently established by percutaneous fine-needle biopsy of the thrombus; malignant thrombosis was seen in 13 patients, and chemical thrombosis was seen in six patients. RESULTS: Pulsatile arterial flow in the thrombus was observed by color Doppler sonography in 12 of the 13 malignant thrombi and in none of the bland thrombi. The flow was hepatopetal in seven cases and hepatofugal in five cases. The peak systolic frequency shift ranged from 0.59 to 2.65 kHz (mean, 1.35 kHz), and the resistive index ranged from 0.37 to 0.69 (mean, 0.55). The sensitivity and the specificity of color Doppler sonography for the detection of tumor thrombosis were 92% and 100%, respectively. CONCLUSION: Our study shows that color Doppler sonography is a reliable way to differentiate between chemical and tumor thromboses of the portal vein in patients with hepatocellular carcinomas treated by ethanol injection. When the sonogram shows pulsatile arterial flow within the thrombus, percutaneous biopsy of the thrombus is unnecessary. The finding is always indicative of malignant thrombosis.

Aged↗

PubMed1995

[Preoperative imaging in the detection of parathyroid tumefaction in patients with primary hyperparathyroidism. The authors' own experience].

The authors report their 3-year experience with the diagnosis of parathyroid lesions in primary hyperparathyroidism patients in a geographic area where the occurrence of endemic goiter is medium. Our study was aimed at prospectively assessing preoperative imaging results in these patients. The following imaging methods were used: high-definition and color-Doppler ultrasonography (US), double-tracer 201Thallium-99mTechnetium (T1/Tc) subtraction scintigraphy, Computed Tomography (CT), Magnetic Resonance Imaging (MRI) and US-guided fine-needle aspiration of the suspected parathyroid lesions. Preoperative US and scintigraphy were performed in 50 patients with primary hyperparathyroidism; in addition, color-Doppler US studies were performed in 33 patients for vascular characterization of the lesions. In 19 patients, the suspected lesions were punctured under US guidance to measure parathormone (PTHa) and thyroglobulin (TGa) levels in the aspirated material. CT and MRI were performed in 9 patients, to identify a possible ectopic parathyroid gland. Surgery demonstrated 48 solitary parathyroid lesions and one double parathyroid adenoma. In one patient no abnormal parathyroid gland was found. Overall sensitivity rates of US and scintigraphy were 85.7% and 61.2%, respectively. In multinodular goiter patients, the sensitivity rates of US and scintigraphy were 71.4% and 47.6%, respectively. At color-Doppler US the presence of parenchymal vascularization was specific of parathyroid nodules and the method helped differentiate parathyroid lesions from thyroid nodules in 14 multinodular goiter patients. Overall PTHa sensitivity was 72.2% and its specificity 100%. Overall TGa sensitivity was 100% and specificity 94.7%. CT and MRI allowed the detection of 8 ectopic parathyroid lesions. In conclusion, in our personal experience, US should be preferred to double-tracer T1/Tc subtraction scintigraphy in the early examination of primary hyperparathyroidism patients. When US detects a suspected parathyroid lesion, color-Doppler US and PTH and TG sampling can make useful diagnostic tools for reducing false-positive results, especially when thyroid disease is associated.

Adolescent↗

PubMed1994

Hepatocellular carcinoma: CT and MR features after transcatheter arterial embolization and percutaneous ethanol injection.

PURPOSE: To investigate the reliability of computed tomography (CT) and magnetic resonance (MR) imaging in the evaluation of the response of hepatocellular carcinoma (HCC) to transcatheter arterial embolization (TAE) followed by percutaneous ethanol injection (PEI). MATERIAL AND METHODS: Between January 1991 and November 1992, 20 patients (15 men and five women, aged 53-73 years [mean, 64.6 years]) with 31 HCC lesions underwent CT and MR imaging before and after treatment with combined TAE and PEI. RESULTS: Twenty-seven tumors, which were hypointense on post-treatment T2-weighted images and on gadolinium-enhanced T1-weighted images, were seen to be necrotic at biopsy. In four cases of incomplete necrosis, viable tumor was hyperintense on T2-weighted images and was enhanced after administration of contrast material. CT provided a larger spectrum of imaging features as a result of the presence of both hyperattenuating areas (caused by retention of iodized oil) and hypoattenuating areas (due to ethanol-induced necrosis). CONCLUSION: CT and MR imaging findings proved useful in the evaluation of the response of HCC to combined TAE and PEI.

Aged↗

PubMed1994

Treatment of hepatocellular carcinoma with percutaneous ethanol injection: evaluation with contrast-enhanced MR imaging.

OBJECTIVE: The aim of this study was to investigate the usefulness of unenhanced and enhanced MR imaging in evaluating the response of hepatocellular carcinoma to percutaneous injection of ethanol. SUBJECTS AND METHODS: Thirty-one patients with 40 hepatocellular carcinomas less than 5 cm in diameter were examined with MR imaging before and after percutaneous injection of ethanol. Unenhanced T1- and T2-weighted and contrast-enhanced T1-weighted spin-echo images were obtained. CT and percutaneous biopsy were performed 1 month after the final injection of ethanol and repeated at 6-month intervals to establish the outcome of treatment: complete tumor necrosis was shown in 36 lesions and incomplete tumor necrosis was seen in four lesions. RESULTS: Of the 36 proved necrotic lesions, 31 showed homogeneously low signal intensity on T2-weighted MR images obtained after treatment, owing to coagulative necrosis of the tumor. In the remaining five necrotic lesions, hypointense and hyperintense areas coexisted; the hyperintense areas were caused by liquefactive necrotic material in two cases and by chronic inflammatory tissue along the boundary of the necrotic area in three cases. None of the 36 necrotic lesions showed contrast enhancement on T1-weighted images obtained after IV injection of gadopentetate dimeglumine. In the four lesions with incomplete necrosis, the viable portion of the tumor was identified as a hyperintense area on T2-weighted images and as an enhancing area on contrast-enhanced T1-weighted images. No correlation was found between lesion features on unenhanced T1-weighted images and outcome of therapy. CONCLUSION: Contrast-enhanced T1-weighted MR images allow a reliable evaluation of the effectiveness of treatment and are more accurate than unenhanced MR studies. Contrast-enhanced MR imaging may be considered a valuable alternative to contrast-enhanced CT in the follow-up of hepatocellular carcinomas treated with percutaneous injection of ethanol.

Aged↗

PubMed1994

[A proposal for the use of tridimensional reconstruction in oncology to better assess tumor stage and response to therapy].

Besides radiation therapy, diagnostic imaging has always been considered the main medical application of three-dimensional (3D) reconstruction. On the contrary, our study focused mainly on the use of 3D reconstruction for both spatial characterization and morphometric evaluation of the reconstructed objects. We aimed at assisting physicians to solve clinical and therapeutic problems. In particular, in oncology, 3D reconstruction may allow the objective and accurate quantification of the volume of neoplastic lesions. Therefore, we decided to focus our attention on the spatial characterization and morphometric assessment of the examined neoplastic masses. Volumetric measurements based on 3D reconstruction may be of great value to assess volume changes after irradiation and/or chemotherapy of neoplastic lesions. This might also allow to compare, on the basis of such changes, the role of different treatment protocols on similar neoplastic lesions and, possibly, to lead to a new TNM staging system no longer based on 2D measurements but on volumes. To meet these clinical requirements, we developed a software system for accurate volume measurements. We believed 3D reconstruction to be suited to this purpose and therefore we implemented a software incorporating 3D reconstruction capabilities of abnormal anatomical structures from 2D images, the rotation of the volume of interest for better assessment of spatial relationships, and finally morphometric evaluation, for accurate volume measurements. Instead of calculating the volume of a neoplastic lesion by means of a 3D reconstruction algorithm considering voxels as indivisible (voxel-based approach), we implemented a surface rendering algorithm using a cell-based approach, because it allowed voxels to be represented as small volume units, which could be further divided by means of linear interpolation. Thus, great flexibility was possible in the determination of surfaces, together with a good approximation of the volume of the neoplastic lesions. To assess the reliability of the developed software system, we used a real phantom. Its known actual volume was compared with the one measured by our system and the difference, expressed as a percentage of the actual volume itself, was compared with the one obtained by using reconstruction algorithms with a voxel-based approach (1.4% vs 4.4%). The error produced by the latter is three times greater than the one produced by our algorithm. This is a major result for the physician: better approximation of the actual volume of a neoplastic lesion means better evaluation of the number of neoplastic cells in the lesion. This may be useful for the clinical management of the patient. In the paper, the first clinical applications of our algorithm are reported.

Algorithms↗

PubMed1994

Long-term follow-up study of adenomatous hyperplasia in liver cirrhosis.

The purpose of this study was to investigate the natural history of adenomatous hyperplasia (AH) in liver cirrhosis, which is suspected of being a precancerous condition of hepatocellular carcinoma (HCC). Sixteen patients with 19 histologically proven AH nodules were followed-up over time with ultrasonographic (US) examinations performed every 3-4 months. The biopsy was repeated whenever the volume of the lesion increased, its US pattern changed, or there was a change in the alpha-fetoprotein values. Thirteen out of 19 AH (68.4%) evolved toward HCC after 8-31 months (mean 14.2 months). Malignant transformation was proved in 7/18 AH within 1 year of its initial detection, in 12/15 AH within 2 years, and in 13/14 AH within 4 years. Six AH remained unchanged in size and US pattern for 9-70 months (mean 29.5 months). Long term follow-up of AH confirms that this lesion is a precursor of HCC.

Adenoma, Liver Cell↗

PubMed1994

[The compression of numerical radiological images].

A digital radiological image is made by a number of pixels, each of them characterized by a definite numerical value obtained by quantization which represents the luminance in that specific image unit. Spatial resolution and dynamic range are the main factors in determining the quality of a digital radiological image. The product of the two above factors defines the global dimensions of the image and is expressed in bits. In conventional radiographic images the global dimension of the image is expressed in MBytes, because of its high spatial and contrast resolution. To reduce the visualization and storage requirements as well as the transmission time of large image data sets, compression algorithms have been recently introduced. These algorithms are based on the fact that often in a digital image parts of the binary data are "redundant", that is they are not necessary for correct image representation. Therefore, compression methods are aimed at reducing both statistical and perceptive redundancy. Statistical redundancy is reduced by means of lossless coding which does not allow to compress images with a ratio higher than 4-5:1 and that--by definition--allows to recover the original image quality. On the other hand "lossy" compression algorithms, which eliminate the perceptive redundancy, are based on the reduction of spatial resolution and dynamic range and on transform-based methods. In particular, the latter have usually been more successful in terms of efficient compression, even when applied to conventional radiographic images. The basic transform procedure can be modified at various levels. JPEG is one of these methods, originally developed for photographic images, which can be usefully applied to radiological images as well. Lossy procedures allow to reach higher compression ratios than lossless methods, but the decrease in information content must be prevented from reducing diagnostic accuracy. In order to assess the diagnostic efficiency of the images compressed with lossy methods, semi-objective analyses are usually performed and ROC curves are produced and evaluated. A model ROC analysis is presented.

Algorithms↗

PubMed1994

[Staging of hepatocellular carcinoma. Comparison of ultrasonography, computerized tomography, magnetic resonance, digital angiography, and computerized tomography with lipiodol].

Accurate staging is necessary in hepatocellular carcinoma (HCC) patients to choose the most appropriate therapeutic approach. In the present study, 50 patients with one or more HCC lesions were prospectively examined with ultrasonography (US), Computed Tomography (CT), Magnetic Resonance Imaging (MRI), digital subtraction angiography (DSA) and CT after intraarterial injection of Lipiodol (Lipiodol CT). The study was aimed at suggesting the most appropriate diagnostic work-up for HCC staging. A hundred and twenty-one HCC lesions were detected in the 50 examined patients by means of the above imaging techniques: namely, 21 patients had single lesions, 15 had two lesions, 4 had three lesions and 10 patients had more than three lesions (range: 4-12). US detected 98/121 lesions (81%), CT 92/121 (76%), MRI 90/121 (74%), DSA 102/121 (84%) and Lipiodol CT 115/121 lesions (95%). The sensitivity of Lipiodol CT was significantly higher than that of all the other imaging techniques (p < 0.05). The detection rate of each technique was correlated with the size of the tumors, which were divided into three groups: lesions < or = 1 cm (no. 28), lesions ranging 1.1 to 3 cm (no. 43) and lesions > 3 cm (no. 50). In the lesions < or = 1 cm, detection rates ranged 29-93%; in this group a statistically significant difference (p < 0.01) was observed between Lipiodol CT and all the other imaging modalities. In the lesions 1.1-3 cm, detection rates ranged 77-93%; in this group a statistically significant difference (p < 0.05) was observed between Lipiodol CT and MRI. In the lesions > 3 cm, sensitivity was very high for all imaging modalities--i.e., 94% or higher; in this group no statistically significant difference was observed among the various imaging modalities. Combined US and CT detected 104/121 lesions (86%), US and MRI 101/121 (83%) and CT and MRI 98/121 (81%). The combination of US, CT and MRI allowed the detection of 107/121 lesions (88%), which markedly improved the results of US alone (the statistical index was just above the one usually considered to be significant). In conclusion, our data suggest the following staging work-up for HCC: (a) US as the first step diagnostic tool; (b) CT and possibly MRI, in the cases with a single lesion at US and in the patients eligible for surgery; (c) Lipiodol CT in the cases which CT and MRI confirmed to be single lesions.

Adult↗

PubMed1994

Lipiodol-CT in the detection of tumor persistence in hepatocellular carcinoma treated with percutaneous ethanol injection.

Our purpose was to investigate the usefulness of Lipiodol-CT for detection of residual viable neoplastic tissue in hepatocellular carcinoma (HCC) lesions treated by means of percutaneous ethanol injection (PEI). An emulsion of 5 to 20 ml iodized oil and 50 to 70 mg doxorubicin hydrochloride was intraarterially injected in 18 patients with 25 HCC lesions treated by means of PEI one to 24 months before. At CT performed 3 to 5 weeks after injection, retention of Lipiodol was observed in 9 of 13 tumors that still contained viable neoplastic tissue and in 2 of 12 tumors proven to have undergone complete necrosis after PEI. The sensitivity and specificity of Lipiodol-CT were 69.2% and 83.3%, respectively. Thus, Lipiodol-CT seems to have limited diagnostic value after PEI, probably as a consequence of the alcohol-induced vascular damage, accounting for both false-negative and false-positive results.

Aged↗

PubMed1994

[Imaging diagnosis in pseudomembranous colitis].

Pseudomembranous colitis (PC) is a dangerous inflammatory disease which arises as a complication of systemic antibiotic therapy. The colon is the preferred localization of PC, which is caused by the alteration in the bacterial population of the bowel which favors the growth and activation of several germ types--e.g., the Clostridium difficile, whose toxins can damage the colonic mucosa deeply. Later, the condition may affect extramucosal structures thus causing an actual parietal alteration. Clinically, PC patients present with diarrhea, abdominal pain, onset or worsening of fever, impairement of the main body functions. The colonic mucosa appears macroscopically edematous and is covered with yellowish plaques, called "pseudomembranes", which adhere strictly to the mucosa. Pseudomembranes are made by fibrin, mucus, leucocytes and epithelial remnants. The diagnosis is made on the basis of laboratory tests--i.e. the demonstration of Clostridium difficile or its toxins in the feces. Endoscopy is the examination of choice when PC is suspected because it can demonstrate the typical mucosal alterations directly. In this paper the main etiologic, pathologic and clinical features of PC are presented and the role of diagnostic imaging examinations is discussed, not only in demonstrating the typical lesions but also in the spatial evaluation of the condition and in its follow-up.

Colon↗

PubMed1994

Percutaneous ethanol injection therapy of adenomatous hyperplastic nodules in cirrhotic liver disease.

Adenomatous hyperplastic nodules (AHNs) in cirrhotic liver are considered a precancerous condition which may lead to hepatocellular carcinoma (HCC). In this study, we treated a total of 23 AHNs in 15 patients with percutaneous ethanol injection (PEI). The treatment included 6 to 8 PEIs, performed on an out-patient basis under sonographic guidance. A 22 G (0.7 mm) spinal needle was used. The total amount of alcohol delivered into each lesion was 8 to 25 ml (mean 14.9 ml). At the end of treatment, complete necrosis of the nodule was proved in all cases by multiple fine-needle biopsies and confirmed by CT and MR findings. During follow-up (9-41 months, mean 24 months) no recurrences were demonstrated. However, HCC occurred elsewhere in the liver of 4 patients and additional AHNs were detected in 2 patients. Thus, PEI proved able to cause complete ablation of AHNs, presumably preventing their malignant transformation. However, patients with AHN remain at high risk for developing HCC.

Aged↗

PubMed1993

Management of adenomatous hyperplastic nodules in the cirrhotic liver: US follow-up or percutaneous alcohol ablation?

In order to investigate the most appropriate management of adenomatous hyperplastic nodules in cirrhosis (AHNs), retrospective and prospective studies were undertaken. The retrospective study included 11 AHNs detected in nine patients, who were followed with ultrasonography (US) and fine-needle biopsy (FNB); seven of these lesions evolved into hepatocellular carcinoma (HCC) after a mean follow-up period of 11.4 months. The prospective study involved 19 AHNs (in 12 patients) that were submitted to percutaneous ethanol injection (PEI); all lesions underwent necrosis at the dynamic computed tomographic (CT) examination and at multiple FNBs performed 1 month after the end of treatment. In four patients studied with magnetic resonance (MR), all treated lesions were markedly hypointense in the T2-weighted images. No complications occurred after a total number of 114 alcohol injections. No local recurrences were observed after a mean follow-up period of 16.9 months. PEI should therefore be considered mandatory in the management of AHNs.

Aged↗

PubMed1993

Neural network segmentation of magnetic resonance spin echo images of the brain.

This paper describes a neural network system to segment magnetic resonance (MR) spin echo images of the brain. Our approach relies on the analysis of MR signal decay and on anatomical knowledge; the system processes two early echoes of a standard multislice sequence. Three main subsystems can be distinguished. The first implements a model of MR signal decay; it synthesizes a four-echo multiecho sequence, in order to add images characterized by long echo-times to the input sequence. The second subsystem exploits a priori anatomical knowledge by producing an image, in which pixels belonging to brain parenchyma are highlighted. Such anatomical information allows the following submodule to distinguish biologically different tissues with similar water content, and hence similar appearance, which might produce misclassifications. The grey levels of the reconstructed sequence and the output of the second module are processed by the third subsystem, which performs the segmentation of the sequence. Each pixel is assigned to one of five different tissue classes that can be revealed with brain MR spin echo imaging. With a suitable encoding, a five-level segmented image can then be produced. The system is based on feed-forward networks trained with the back-propagation algorithm; experiments to assess its performance have been carried out on both simulated and clinical images.

Brain↗