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Biomedical subjects

A M De Gaetano

Publications and source records attributed to A M De Gaetano.

At least 19 recordsLinked to original sources
PubMed2004

Congenital absence of the portal vein associated with focal nodular hyperplasia in the liver in an adult woman: imaging and review of the literature.

We present a new case of congenital absence of the portal vein and focal nodular hyperplasia in the liver without additional congenital anomalies. Ultrasound, computed tomography, magnetic resonance imaging, and angiography depicted the splenic vein and the superior mesenteric vein joining and entering into the inferior vena cava without passing through the liver. The features of this patient and the 30 previously reported cases are reviewed.

Abdominal Pain↗
PubMed2000

Color Doppler sonography in the diagnosis and monitoring of arterial complications after liver transplantation.

PURPOSE: We assessed the usefulness of color Doppler imaging in the diagnosis and monitoring of arterial complications after liver transplantation. METHODS: Subjects were 142 liver transplant recipients who underwent serial color Doppler sonographic evaluations of the hepatic arteries after surgery. Patients with abnormal sonographic findings underwent subsequent angiography. RESULTS: Eighteen subjects experienced 20 hepatic arterial complications (13 thromboses and 7 stenoses). In 7 of the 13 thrombosis incidents, hepatic arterial obstruction occurred within a month of surgery and was evident from the absence of Doppler signals; angiography confirmed the absence of hepatic arterial perfusion in these cases. In the other 6 thrombosis cases, the thrombosis developed 3 or more months after surgery and became apparent from the absence of color Doppler signals at the level of the main arterial trunk and the presence of intraparenchymal "tardus parvus" waveforms. In these cases, angiography showed obstruction of the main arterial trunk and the development of compensatory collateral vessels. In 3 of the 7 cases of stenosis, high flow velocities were recorded at the site of the narrowing, and intrahepatic tardus parvus waveforms were present. In the other 4 stenosis cases, the site of stenosis could not be identified, but intraparenchymal tardus parvus waveforms were recorded. CONCLUSION: The use of color Doppler sonography allows the early diagnosis of hepatic arterial complications after liver transplantation. Tardus parvus waveforms indicated severe impairment of hepatic arterial perfusion, from either thrombosis or severe stenosis. The presence of these waveforms enhanced the accuracy of color Doppler diagnosis (100% positive predictive value), and their detection should prompt angiography.

Adult↗
PubMed1999

Delayed MR imaging of hepatocellular carcinoma enhanced by gadobenate dimeglumine (Gd-BOPTA).

The purpose of this study was to determine the efficacy of gadobenate dimeglumine (Gd-BOPTA)-enhanced magnetic resonance (MR) imaging for evaluation of hepatocellular carcinoma HCC. MR images were obtained in 14 patients with 31 HCC nodules as a part of a phase III clinical trial. T1- and T2-weighted images were obtained before and after iv administration of 0.1 mmol/kg of Gd-BOPTA. Two blinded readers evaluated pre- and delayed postcontrast images separately for detection of tumor nodules. Quantitative measurements of signal-to-noise (SNR) and tumor/liver contrast-to-noise (CNR) ratios were also performed. A signal/intensity ratio was calculated. Tumor enhancement was correlated with histologic findings. Consensus agreement of precontrast T1- and T2-weighted images revealed 23/31 HCC nodules in 14 patients; postcontrast T1-weighted images demonstrated 24/31 HCC nodules in the same number of patients. Combining both pre- and postcontrast images, 27/31 lesions were detected. Four patients had four well-differentiated HCC nodules detected only on postcontrast images, while three well-differentiated lesions in two patients were only seen on precontrast images. Quantitative evaluation showed an SNR ratio increase in both liver parenchyma and HCC nodules, as well as a significant increase in the absolute CNR ratio on postcontrast T1-weighted gradient-recalled images (P < 0.05). Well-differentiated HCC lesions showed a greater enhancement than poorly differentiated HCC lesions.

Aged↗
PubMed1995

Cavernous transformation of the portal vein: patterns of intrahepatic and splanchnic collateral circulation detected with Doppler sonography.

OBJECTIVE: Cavernous transformation of the portal vein is defined as the formation of venous channels within or around a previously thrombosed portal vein. The purpose of this work was to study the hemodynamic consequences of cavernous transformation of the portal vein in a group of afflicted patients by use of Doppler sonography. We wished to study the evolution from portal vein thrombosis to the formation of cavernous transformation, the extent of resulting extrahepatic collateral channels, and the patterns of splanchnic collateral circulation. MATERIALS AND METHODS: Seventy-five patients (48 adults and 27 children) with cavernous transformation of the portal vein were studied with color and/or pulsed Doppler sonography. Blood flow in the extrahepatic portal vein, in its segmental branches, in the hepatic veins and artery, and in the splanchnic veins was examined. Collateral pathways were sought. For nine patients with acute thrombosis of the portal vein, serial examinations were performed during the formation of cavernous transformation. RESULTS: In nine patients, a fresh thrombus filled and distended the portal vein and became recanalized within a few days. Tortuous vessels appeared at the porta hepatis. These were characterized as veins or arteries with Doppler sonography. Soon the portal vein could no longer be identified within the mass of tortuous vessels. The cavernous transformation developed within 6-20 days of the acute thrombosis. A spongelike mass of collateral vessels around the main portal vein was seen in all but two patients. Intrahepatic extension of the cavernous transformation was seen in 57 patients (76%) and involved one or more intrahepatic portal veins. Two types of collateral circulation were observed: portosystemic, mainly through the left gastric and the perisplenic veins (the caput medusae, i.e., the paraumbilical-to-abdominal venous route, was never seen); and portoportal, from the periportal or pericholecystic venous channels to the intrahepatic portal veins. In nine patients, flow within unaffected intrahepatic branches of the portal vein was reversed as directed toward the cavernous transformation surrounding other, thrombosed intrahepatic segments of the portal vein. CONCLUSION: After thrombosis of the portal vein, portoportal venous channels may form not only at the porta hepatis but also within the liver. Intrahepatic blood may be shunted from one segmental portal vein to another. In addition, portosystemic collateral channels are formed, suggesting that, despite extensive hemodynamic adaptations, portal hypertension ensues.

Acute Disease↗
PubMed1995

[The tissue characterization of focal liver lesions with magnetic resonance imaging].

This study was aimed at assessing the accuracy of Magnetic Resonance Imaging (MRI) in the characterization of focal liver masses. We prospectively examined 51 patients with focal liver masses: the morphological features were investigated with different pulse sequences and the functional characteristics were studied after the i.v. administration of Gd-DTPA (2 mmol/kg). MR findings were compared with those of gold standard methods, i.e., percutaneous biopsy, surgery or, for hemangiomas, 99mTc-labelled blood cell liver scintigraphy. All hemangiomas presented with typical features: signal intensity was very high on long TE images (> 140 msec) and a globular enhancement pattern, with centripetal progression, was observed after dynamic studies. This signal pattern on T2-weighted images is highly indicative of hemangioma. Five of 7 focal nodular hyperplasias (71%) were isointense with hepatic parenchyma on all pulse sequences; the central scar was observed in 5/7 cases on short TR/TE images and in all cases on long TR/TE images in 16/17 cases (94%). High signal intensity on T1-weighted images was statistically significant for HCC. A pseudocapsule was observed in 12 cases (70%). A mosaic pattern on T2-weighted images was observed in 3 cases. Seventy-four per cent of HCCs exhibited signal enhancement during the arterial phase of the dynamic study. Metastases presented a uniform pattern, i.e., they were hypointense on T1-weighted and hyperintense on T2-weighted images in 12/13 cases (92%). A central hypointense area on T2-weighted images is indicative of coagulative necrosis. A lesion with these morphological features and hypovascular signal is suggestive of metastasis.

Biopsy, Needle↗
PubMed1995

[The tissue characterization of focal liver lesions by color Doppler echography].

To investigate color-Doppler capabilities in tissue characterization, 47 hepatic lesions were studied. The real-time morphologic appearance of the lesions was studied first and then color flow images were acquired, assessing color areas and the distribution of blood flow for each lesion. For quantitative Doppler study, the color Doppler signal was used as a guide to obtain the Doppler spectrum and to measure flow velocities and pulsatility index (PI) values. Data were plotted and analyzed statistically; criteria for differentiating malignant from benign hepatic tumors and the patterns suggestive of either condition were proposed. Absolutely no Doppler signal was observed in avascular or necrotic lesions and in low-flow tumors, e.g., metastases (10%) and hemangiomas (63%). Many color signals at the periphery and within tumor masses were observed in highly vascular lesions, e.g., hepatocellular carcinomas (60%) and focal nodular hyperplasia (80%). Multiple afferent vessels and a "basket-like" pattern were detected in a high percentage of hepatocellular carcinomas. High-flow velocities (> 0.85 m/s perilesional systolic velocity and > 0.80 m/s intralesional systolic velocity) and high PI values (> 1.5 perilesional PI and > 0.90 intralesional PI) are suggestive of malignancy. Particularly, 0.90 intralesional PI cutoff value exhibits 89% specificity and 82% sensitivity in benign versus malignant differential diagnosis. Our results suggest that color-Doppler US is a useful means of studying the hemodynamics of hepatic tumors which increases US diagnostic accuracy.

Diagnosis, Differential↗
PubMed1995

[Color Doppler echography in the tissue characterization of renal masses].

To investigate color-Doppler US capabilities in tissue characterization, 42 renal masses were studied from November, 1993, to July, 1994. B-mode morphologic patterns were studied first and then integrated with color flow patterns; color areas and blood flow distribution were assessed for each lesion. Color signals were used as a guide to obtain arterial and venous Doppler spectra and to calculate flow velocities and pulsatility index (PI). Based on the us morphologic appearance, the 42 lesions were divided into 3 groups: A) lesions with morphologic and volumetric patterns of malignancy; B) small lesions (< 3 cm, > 3 cm < 5 cm); C) complex cysts. Data were organized and analyzed statistically; some findings were found to be typical of malignancy: hypervascularity, intralesional arterial signals with high flow velocities (systolic peak cut-off: 0.3-0.4 m/sec), high PI values (> 1) and, finally, color signals inside complex cysts. Our results suggest that color-Doppler US is a useful tool to assess renal masses vascularity, with the color-Doppler technique increasing US diagnostic accuracy. Nevertheless, small lesions need more careful study because their features are poorly demonstrated even with CT and MRI.

Adenocarcinoma↗
PubMed1994

Color Doppler ultrasonography in the differential diagnosis of focal hepatic lesions. The SH U 508 A (Levovist) experience.

The differential diagnosis of focal hepatic lesions is a current problem even though many study methods are available. Color Doppler US has been recently suggested as a diagnostic technique capable of depicting lesion vascularization patterns to better understand lesion nature. However, this examination is often difficult and long. In this study, we investigated the role of a US contrast agent SH U 508 A (Levovist) enhancing the color Doppler signals for easier and better depiction of lesion vascularization. Seventy-four patients with one or more focal hepatic lesions (mean diameter: 5.6 cm) were examined. The lesions were 38 HCCs, 4 cholangiocarcinomas, 1 intrahepatic biliary duct carcinoma, 1 case of multiple adenomas, 2 regenerations nodules in cirrhosis, 2 cases of FNH, 18 metastases and 8 hemangiomas. In 54 cases the US contrast agent allowed the visualization of some vessels inside the lesions which had been missed at baseline examinations. Moreover, the vessels which had been depicted on baseline images were better demonstrated. In all but one patient with severe hepatic steatosis, normal parenchymal vessels were markedly enhanced. Our results in the different kinds of tumors are here reported.

Color↗
PubMed1993

[Echo-Doppler in the study of pre- and post-hepatic portal hypertension].

Portal hypertension is due to a number of pathologic processes; these conditions cause hypertension mostly by hindering the portal flow. The obstacle to portal flow may be located at three different levels--i.e., subhepatic, intrahepatic and suprahepatic. The intrahepatic obstacle is observed in 95% of patients with portal hypertension, while the extra-hepatic causes are rare. This paper is aimed at assessing the diagnostic capabilities of color-Doppler US in the evaluation of pre- and posthepatic portal hypertension. This technique, combining morphologic and Doppler data, allows hypertension to be demonstrated and its degree to be assessed. Color-Doppler US can also define the intra/extrahepatic cause and the level of the obstacle to portal flow. In the diagnosis of the involved processes, the role of color-Doppler US is discussed and compared to the roles of other techniques.

Budd-Chiari Syndrome↗
PubMed1989

[Hepatobiliary scintigraphy in the study of neonatal hepatic cholestasis].

Severe neonatal cholestasis is a clinical problem requiring a differential diagnosis of intra- (hepatitis) and extrahepatic (biliary atresia) causes, prognosis and therapy being different in the two cases. Eighteen patients of pediatric age underwent US and hepatobiliary scintigraphy. US findings were aspecific in both hepatitis and biliary atresia. In the 11 patients with hepatitis, hepatobiliary scintigraphy after phenobarbital revealed labeled bile in the bowel. Only in 1 patient with cytomegalovirus hepatitis was a scintigraphic pattern similar to that of biliary atresia. On the contrary, no intestinal radioactivity within 24 hours was seen in 6 patients with biliary atresia. A portoenterostomy (Kasai's operation) was performed on 4/6 cases with biliary atresia. These patients were followed with hepatobiliary scintigraphy in order to evaluate anastomotic functionality. In a case of biliary cirrhosis secondary to occlusion, orthotopic liver transplantation was performed whose success was scintigraphically monitored. Our results point to hepatobiliary scintigraphy after phenobarbital as the best noninvasive procedure for both diagnosis and postoperative follow-up of biliary atresia. Labeled bile excretion within 24 hours was rarely found in both atresia and neonatal hepatitis.

Biliary Atresia↗
PubMed1987

[Comparison of ultrasound and radiology in the intraoperative diagnosis of nephrolithiasis].

Both intraoperative ultrasonography and radiology were utilized as a surgical aid while operating on 53 patients with renal lithiasis. A thorough comparison was made between the two imaging techniques: intraoperative US showed higher levels of sensitivity and accuracy, while specificity was maximal in intraoperative radiology. Intraoperative US proved to be a versatile and safe diagnostic procedure--as well as easy and quick to perform--whose accuracy in localizing stones as well as residual fragments appeared to be extremely high. Intraoperative US assistance during surgical procedures for renal lithiasis proves thus to be of the utmost importance in urologic practice.

Evaluation Studies as Topic↗