Biomedical subjects
Publications and source records attributed to M Lafortune.
Ultrasonography is an excellent tool for the study of the anatomy of the human liver. This article shows, with the help of sonographic views along the long axis of portal and hepatic veins, and the different landmarks of the liver, how to delineate the eight segments of the liver. Doppler examination allows indentification of the portal veins and the hepatic arteries in the portal triad.
OBJECTIVE: In the present study we evaluated the predictive value of pretransjugular intrahepatic portosystemic shunt (TIPS) portal perfusion as assessed by Doppler ultrasonography for the onset of chronic encephalopathy after TIPS. METHODS: A total of 231 cirrhotic patients were followed-up prospectively after TIPS placement. The pattern of intrahepatic portal flow was assessed before TIPS. Patients were divided into two groups according to Doppler findings. Group 1 comprised patients with prograde portal flow (n = 200), whereas group 2 comprised those with loss of portal perfusion (hepatofugal or back-and-forth flow or portal vein thrombosis; n = 31). The presence of chronic encephalopathy during a median follow-up of 32 months was prospectively recorded. The prognostic value of the following parameters for the onset of chronic recurrent encephalopathy after TIPS was evaluated: age, presence of encephalopathy before TIPS, alcoholism, Pugh score, and loss of portal perfusion before TIPS. The independent prognostic value of each variable was tested with a multiple logistic regression analysis. RESULTS: The two groups were comparable in terms of age, incidence of prior episodes of hepatic encephalopathy, and portacaval gradient before and after the procedure; however, liver failure was more severe in patients in group 2 (Pugh score: 9.2 +/- 1.9 vs 10.3 +/- 1.7). The 3-yr survival was identical for both groups; 25% of the 200 patients in group 1 developed chronic encephalopathy as compared to 6% of the 31 patients in group 2 (p = 0.03). Multiple logistic regression analysis demonstrated that loss of portal perfusion and age >65 yr were the only independent predictors of the onset of post-TIPS chronic encephalopathy (odds ratios 0.24 and 1.98, respectively). CONCLUSIONS: Cirrhotic patients with loss of portal perfusion before TIPS were protected against post-TIPS chronic hepatic encephalopathy despite a more severe liver dysfunction at baseline. The only other independent predictive factor for the onset of this complication was age.
BACKGROUND AND AIMS: The transjugular intrahepatic portosystemic shunt (TIPS) is a new therapeutic modality for variceal bleeding. In this study we compared the two year survival and rebleeding rates in cirrhotic patients treated by either variceal band ligation or TIPS for variceal bleeding. METHODS: Eighty cirrhotic patients (Pugh score 7-12) with variceal bleeding were randomly allocated to TIPS (n=41) or ligation (n=39), 24 hours after control of bleeding. RESULTS: Mean follow up was 581 days in the ligation group and 678 days in the TIPS group. The two year survival rate was 57% in the TIPS group and 56% in the ligation group (NS); the incidence of variceal rebleeding after two years was 18% in the TIPS group and 66% in the ligation group (p<0.001). Uncontrolled rebleeding occurred in 11 patients in the ligation group (eight were rescued by emergency TIPS) but in none of the TIPS group. The incidence of encephalopathy at two years was 47% in the TIPS group and 44% in the ligation group (NS). CONCLUSIONS: TIPS did not increase the two year survival rate compared with variceal band ligation after variceal bleeding in cirrhotic patients with moderate or severe liver failure. It significantly reduced the incidence of variceal rebleeding without increasing the rate of encephalopathy.
OBJECTIVE: The aim of the study was to determine the sonographic findings of snapping hip and to correlate the findings with the presence or absence of pain. MATERIALS AND METHODS: Twenty patients with snapping hip were examined with sonography. Conventional and dynamic sonographic examinations of both hips were performed using a 5.0- or 7.0-MHz transducer. RESULTS: Conventional sonographic studies allowed identification of various structural abnormalities (tendinitis, bursitis, synovitis) and helped to document tenderness along the course of specific tendons. Dynamic sonographic studies revealed 26 cases of snapping hip. In 24 of these 26 cases, the underlying cause was clearly identified. Twenty-two snapping hips were caused by an abnormal movement of the iliopsoas tendon, and two were caused by iliotibial band friction over the greater trochanter. One patient reported a bilateral snapping sensation that could not be documented on sonography. Snapping hip was elicited by a wide variety of hip movements. Sonography established an immediate temporal correlation between the jerky tendon motion and the painful snap reported by the patient. Only 14 cases of snapping hip were painful. CONCLUSION: Conventional sonographic studies can identify signs of tendinitis, bursitis, or synovitis. Dynamic sonographic studies revealed the cause of snapping hip in most patients. Snapping hip is characterized on sonography by a sudden abnormal displacement of the snapping structure. In our study, a significant proportion of the cases of snapping hip were not painful.
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BACKGROUND: Tyrosinemia relates to a deficiency of fumarylacetoacetate hydrolase and presents early in life with central nervous system and liver abnormalities. Renal function is often impaired. Little is known about the architecture and function of the kidneys. OBJECTIVE: Imaging changes on US and CT are compared to the function of the kidneys in children with tyrosinemia, and followed after liver transplantation. MATERIALS AND METHODS: Renal sonography, CT and renal function tests in 32 children were reviewed. Renal length, volume, echogenicity and nephrocalcinosis were evaluated. Renal function was assessed by glomerular filtration rate, and the presence of aminoaciduria, acidosis and calciuria. Seventeen children had open renal biopsy during time of liver transplantation. Histology was reviewed. Statistical analyses relating renal structure to function were performed, and repeated after transplantation. RESULTS: The kidneys were enlarged (47 %), hyperechogenic (47 %) and showed nephrocalcinosis (16 %). There was delayed excretion of contrast medium at CT in 64 %. Aminoaciduria was present in 82 % of children, hypercalciuria in 67 %, tubular acidosis in 59 %, and low GFR in 48 %. Delayed excretion of contrast was associated with low GFR (P < 0.05). Renal biopsies showed dilated tubules (81 %), interstitial fibrosis (56 %), glomerulosclerosis (56 %) and tubular atrophy (56 %). During a mean observation period of 3 years following liver transplantation, GFR improved in 50 %, tubular acidosis in 50 % and hypercalciuria in 70 %. No change was noted in renal size or sonographic architecture. CONCLUSION: Renal architecture and function are abnormal in the majority of children with tyrosinemia. Liver transplantation improves renal function in about 50 % of patients, but abnormal renal size and architecture persist.
OBJECTIVE: Transjugular intrahepatic portosystemic shunt (TIPS) is used increasingly as a treatment for refractory ascites. The aim of the present study was to determine the prognostic value of different parameters in predicting a favorable evolution following TIPS in a cohort of 53 cirrhotic patients without organic renal disease and with refractory ascites. METHODS: Patients were classified as good responders if they survived more than 6 months, without severe chronic hepatic encephalopathy and with good control of ascites. The prognostic value for a good outcome was evaluated using age, creatinine clearance, plasma renin activity, plasma aldosterone, and Pugh score. RESULTS: Good control of ascites was obtained in 90%. The cumulative survival rate was 54% at 6 months, 48% at 1 yr, and 39% at 2 yr. The vast majority of patients died of complications of hepatic insufficiency. Severe chronic hepatic encephalopathy developed in 26%. Overall, a good clinical response was observed in 47%. Creatinine clearance was identified as the only pre-TIPS factor to be significantly and independently associated with a good clinical response to TIPS for refractory ascites. A good clinical response was observed in 57% of patients with a creatinine clearance >36 ml/min compared to 9% of those with a clearance <36 ml/min (p < 0.01). This cutoff point in creatinine clearance had a sensitivity of 96% and a specificity of 36%; positive predictive and negative predictive values were 57% and 90%, respectively. CONCLUSIONS: TIPS might be useful for the treatment of refractory ascites in cirrhotic patients without severe renal function impairment. However, the TIPS usefulness still has to be demonstrated compared to large volume paracentesis or Leveen shunt. In patients with poor renal function or with liver failure after TIPS, liver transplantation should be considered.
PURPOSE: To evaluate the dimensions of segment 4 of the liver in patients with cirrhosis by using ultrasonography (US). MATERIALS AND METHODS: The transverse diameter of segment 4 was measured in 125 control subjects without liver disease and 167 patients with cirrhosis. The size of segment 4 was measured on oblique subcostal US scans obtained between the left wall of the gallbladder (or the main fissure after cholecystectomy) and the ascending or umbilical portion of the left portal vein at the point where it gives rise to the branch to segment 4. RESULTS: In the control subject group, the mean diameter of segment 4 was 43 mm +/- 8 (standard deviation). In the patient group, the mean diameter of segment 4 was 28 mm +/- 9. The cause or severity of cirrhosis had no influence on the size of segment 4. CONCLUSION: A decreased diameter of segment 4 may be a helpful adjunct sign of cirrhosis in the US investigation of chronic liver disease.
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OBJECTIVE: We report three cases of a rare form of cavernoma developed within the wall of the common bile duct. CONCLUSION: To our knowledge, this kind of portal cavernoma has not been described in the literature. Because the cavernoma may be easily confused with other causes of bile duct wall thickening, color Doppler sonography is mandatory for a correct diagnosis.
Blood flow within the major arteries supplying the brain can be studied with transcranial Doppler sonography, a noninvasive, portable procedure. We describe the technique of examination, as well as indications in children and adults such as the investigation of intracranial stenosis, collateral pathways, vasospasm, cerebral emboli and arteriovenous malformations.
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Ascites becomes refractory to medical treatment in nearly 10% of cirrhotic patients, who then require repeated large-volume paracentesis. In this prospective study we evaluated the use of transjugular intrahepatic portosystemic shunt (TIPS) in 30 patients with refractory ascites. TIPS was successful in all and resulted in a 54% reduction in portacaval gradient (from 22.8 +/- 0.8 to 10.4 +/- 0.6 mm Hg). Ascites became easily controlled with diuretics in 26 patients following TIPS. Ascites recurrence associated with shunt stenosis was observed during follow-up in eight patients; revision could be undertaken in five of them and resulted in good control of ascites. In responders, a marked decrease in plasma aldosterone and renin activity, a reduction in serum creatinine, and a rise in urinary sodium excretion were observed. Creatinine and inulin clearances improved significantly; PAH clearance remained unchanged. However, new-onset or worsening hepatic encephalopathy was seen in 14 patients. Severe disabling chronic encephalopathy occurred in five patients; it could be reversed successfully by balloon occlusion of the shunt in three. The cumulative survival rate was 41 and 34% at 1 and 2 years, respectively. In summary, TIPS can control refractory ascites in a majority of patients but is associated with a high rate of chronic disabling HE. In addition, the survival rate is poor. Randomized trials are needed to evaluate the exact role of TIPS in the management of refractory ascites. It is unlikely to improve survival but can ameliorate quality of life in nontransplant candidates and be useful as a bridge to transplantation, in particular, to improve denutrition associated with longstanding tense ascites.
OBJECTIVE: The purpose of our study was to describe Doppler sonography patterns of venous flow in the portal system of healthy subjects and to compare pulsatility of flow with subjects' body mass, degree of inspiration, and body position. SUBJECTS AND METHODS: Doppler signals from the main, right, and left portal veins; superior mesenteric vein; splenic vein; and inferior vena cava of 23 healthy adults were prospectively studied. Pulsatility of flow was quantified using an index of venous pulsatility (VPI = [maximum frequency shift-minimum frequency shift]/maximum frequency shift). Antegrade flow peak velocities were also related to ECG tracings the time between two R waves being divided into four equal parts for analysis. The caliber variations of the main portal vein and inferior vena cava were measured with M-mode sonography. Doppler tracings were obtained with subjects in supine and sitting positions and during mid and deep inspiration. The subjects' heights and weights were obtained and the body mass index calculated (weight/[height2]). RESULTS: In the portal vein, the VPI was 0.48 +/- 0.31 (mean +/- SD). Marked pulsatility of venous flow (VPI > 0.5) was found in 12 of 23 subjects. We found an inverse correlation between the VPI and the subjects' body mass index (r = -.76; p < .001). Portal vein pulsatility decreased significantly during sitting (p < .05) and deep inspiration (p < .01). The portal VPI was correlated with caliber variation of the inferior vena cava (r = .59; p < .05). In the portal venous system, antegrade flow peak velocities occurred most often during the third quarter of the cardiac cycle, particularly in the splenic vein. CONCLUSION: Doppler sonography shows pulsatile portal venous flow in healthy adults, especially in thin subjects. This pulsatility has an inverse correlation to body mass. The finding of a pulsatile portal vein needs to be interpreted in clinical context and does not necessarily imply dysfunction of the right side of the heart.
BACKGROUND AND AIMS: In portal hypertensive patients, transjugular intrahepatic portosystemic shunt (TIPS) acutely increases cardiac output and exaggerates peripheral vasodilatation. It has been suggested that the worsened hyperdynamic state may progress to high output heart failure. The aim was to evaluate the acute and short-term haemodynamic adaptation to this procedure. METHODS: Systemic, splanchnic, and pulmonary haemodynamics were studied in 15 cirrhotic patients under stable haemodynamic conditions before placement of TIPS, then 15-30 minutes after and two months later. For inclusion in the final analysis, an uneventful post-TIPS at two months follow up and a stable portacaval gradient were required. The following variables were measured or calculated: portacaval gradient; cardiac index (thermodilution); systolic and diastolic mean arterial, atrial, pulmonary arterial, and wedged pulmonary capillary pressures; heart rate; and total peripheral and pulmonary vascular resistances. Blood flow in the shunt was measured using duplex Doppler ultrasound. RESULTS: The portacaval gradient decreased by 56% and remained stable thereafter. Shunt blood flow was unchanged when measured immediately after TIPS and two months later. Immediately after TIPS there was a pronounced increase in cardiac index (+32%; p < 0.05) in association with a decrease in peripheral and pulmonary vascular resistance (-21%; p < 0.05 and -14%; NS). Two months later, whereas the initial rise in cardiac index was attenuated, peripheral vascular resistances remained similar and pulmonary vascular resistances decreased further (-33%; p < 0.05) compared with immediate post-TIPS values. CONCLUSIONS: Hyperdynamic circulation worsened immediately after TIPS, with a progressive adaptation during follow up. The mechanisms of post-TIPS induced haemodynamic changes include an abrupt volume load resulting from splanchnic decompression and an increased delivery of gut derived vasodilators to the systemic circulation. The persistence of decreased peripheral and pulmonary vascular resistances despite the reduction in high cardiac output two months after TIPS suggests that vasodilatation is not solely a compensatory response to a TIPS induced increased preload. Vasodilatory substances shunted away from the liver probably play an important part in this phenomenon.
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OBJECTIVE: The purpose of this study was to determine the following: whether the arterial supply of a normal appendix is visible with Doppler sonography; whether the physiologic vasodilatation that accompanies childhood appendicitis is visible; what Doppler patterns appear once necrosis of the appendix has occurred; what Doppler shifts are visible with chronic, recurrent appendicitis; and whether other conditions in the right lower quadrant can mimic the Doppler sonographic patterns of appendicitis. MATERIALS AND METHODS: Twenty-five fasting patients without abdominal pain or intestinal disease and 45 patients (1-25 years old; mean, 8 years old) with right lower quadrant pain and suspected appendicitis were examined sonographically, using 5- and 7-MHz linear, color, and pulsed Doppler transducers. Arterial signals were sought within the appendix and neighboring tissues, counted, and classified as sparse (1-2), moderate (3-4), or abundant (>4). The resistive index (RI) was measured. Thirty patients who underwent surgery were retained for surgical and pathologic correlation, and only they formed the appendicitis study. RESULTS: A normal appendix was found in 10 patients. Doppler shifts were sparse, and diastolic flow was low or absent (RI, 0.85-1). Acute uncomplicated appendicitis was found in 13 patients, who had abundant color Doppler signals throughout most of the appendix, with high diastolic flow (RI, 0.40-0.77; mean, 0.54). Acute necrotic appendicitis with perforation was found in 11 children, eight of whom showed no signals in the necrotic area at the tip. Few or no signals were seen in the remainder of the appendix (RI, 0.33-0.90; mean, 0.54). In two patients, signals were abundant in the tissues surrounding the appendix. Recurrent or chronic appendicitis was found in three patients, previously diagnosed as having Crohn's disease, psychosomatic illness, or nonspecific abdominal pain. The appendix had Doppler signals confined to the tip (RI, 0.63-0.83; mean, 0.75). Other diagnoses were found in three patients, in whom the appendix was not seen. There were abundant color signals in the intestinal wall and adjacent tissues in the right lower quadrant. Two patients had Crohn's disease, and the third had an unsuspected early pregnancy. The appendix was normal in all. CONCLUSION: Acute appendicitis is accompanied by inflammatory hypervascularity reflected as an increased number of color signals and higher diastolic Doppler shifts as compared with those found in normal persons. No Doppler shifts are identified in areas of appendiceal ischemia. Other acute inflammation in the right lower quadrant also produces numerous Doppler shifts with high diastolic flow, as does ovulation. Care must be taken to identify the source of these Doppler signals. The changing vascularity of healing, recurrent, and chronic appendicitis promises to further our understanding of the pathogenesis and evolution of this disease.