Hepatic abscess: Diagnosis and management.

Microbial contamination of the liver parenchyma leading to hepatic abscess (HA) can occur via the bile ducts or vessels (arterial or portal) or directly, by contiguity. Infection is usually bacterial, sometimes parasitic, or very rarely fungal. In the Western world, bacterial (pyogenic) HA is most prevalent; the mortality is high approaching 15%, due mostly to patient debilitation and persistence of the underlying cause. In South-East Asia and Africa, amebic infection is the most frequent cause. The etiologies of HA are multiple including lithiasic biliary disease (cholecystitis, cholangitis), intra-abdominal collections (appendicitis, sigmoid diverticulitis, Crohn's disease), and bile duct ischemia secondary to pancreatoduodenectomy, liver transplantation, interventional techniques (radio-frequency ablation, intra-arterial chemo-embolization), and/or liver trauma. More rarely, HA occurs in the wake of septicemia either on healthy or preexisting liver diseases (biliary cysts, hydatid cyst, cystic or necrotic metastases). The incidence of HA secondary to Klebsiella pneumoniae is increasing and can give rise to other distant septic metastases. The diagnosis of HA depends mainly on imaging (sonography and/or CT scan), with confirmation by needle aspiration for bacteriology studies. The therapeutic strategy consists of bactericidal antibiotics, adapted to the germs, sometimes in combination with percutaneous or surgical drainage, and control of the primary source. The presence of bile in the aspirate or drainage fluid attests to communication with the biliary tree and calls for biliary MRI looking for obstruction. When faced with HA, the attending physician should seek advice from a multi-specialty team including an interventional radiologist, a hepatobiliary surgeon and an infectious disease specialist. This should help to determine the origin and mechanisms responsible for the abscess, and to then propose the best appropriate treatment. The presence of chronic enteric biliary contamination (i.e., sphincterotomy, bilio-enterostomy) should be determined before performing radio-frequency ablation and/or chemo-embolization; substantial stenosis of the celiac trunk should be detected before performing pancreatoduodenectomy to help avoid iatrogenic HA.

Simultaneous surgical repair for combined biliary and arterial stenoses after liver transplantation.

After orthotopic liver transplantation (OLT), hepatic artery stenoses (HAS) and biliary strictures (BS) are frequent. These complications remain a significant cause of graft loss and patient death. The present study reported a group of 7 patients in whom both HAS and BS were identified and treated surgically in the same surgical session. The median times to diagnosis were 42 (range, 5-120) and 84 (range, 15-280) days after OLT for biliary and arterial stenosis, respectively. The mortality was nil. Two patients (28%) developed postoperative complications. The median hospital stay was 16 days (range, 10-42). All patients are alive; there was no graft loss. With a median of 76 months' follow-up (range, 38-132), only 1 patient (14%) developed recurrence of both BS and HAS. In patients with coincident biliary and artery stenosis, concomitant surgical repair is feasible, offering good long-term results.

[Postoperative imaging of the peritoneum and abdominal wall]. / Imagerie post-opératoire du péritoine et de la paroi abdominale.

CT scan is the gold standard for follow-up after abdominal surgery and diagnosis of postoperative complications. During the immediate postoperative period, asymptomatic and rapidly regressing peritoneal collections of fluid and gas are often present. Transient ileus is classically present as well. The diagnosis of postoperative peritonitis is difficult on imaging; fluid collections are frequent and easily detected. The main postoperative peritoneal complication is small bowel obstruction, either early and due to inflammatory changes, or delayed and due to adhesions or less frequently to other causes, including transmesenteric hernia. Other rare complications include desmoid tumors and gossypiboma. Wall complications, after laparotomy as well as laparoscopic surgery, are mainly hematoma, infections and wound hernia.

Right portal vein ligation is as efficient as portal vein embolization to induce hypertrophy of the left liver remnant.

BACKGROUND: Aim of this retrospective study was to compare induction of left liver hypertrophy after right portal vein ligation (PVL) and right portal vein embolization (PVE) before right hepatectomy for liver metastases. MATERIALS AND METHODS: Between 1998 and 2005, 18 patients underwent a PVE, whereas 17 patients underwent a PVL during a first stage laparotomy. RESULTS: There was no complication related to PVE or PVL. After a similar interval time (7 +/- 3 vs 8 +/- 3 weeks), the increase of the left liver volume was similar between the two groups (35 +/- 38 vs 38 +/- 26%). After PVE and PVL, right hepatectomy was performed in 12 and 14 patients, respectively. Technical difficulties during the right hepatectomy were similar according to duration of procedure (6.4 +/- 1 vs 6.7 +/- 1 h, p = 0.7) and transfusion rates (33 vs 28%, p = 0.7). Mortality was nil in both groups, and morbidity rates were respectively 58% for the PVE group and 36% for the PVL group (p = 0.6). CONCLUSION: Right PVL and PVE result in a comparable hypertrophy of the left liver. During the first laparotomy of a two-step liver resection, PVL can be efficiently and safely performed.

[Liver imaging: pitfalls, pseudolesions and pseudotumors]. / Imagerie hépatique: pièges, pseudolésions et pseudotumeurs.

Recognition of pseudolesions of the liver at imaging is important because of their close resemblance to primary liver cancer or metastases. There are several types of pseudolesions: pseudolesions, with mostly straight borders, corresponding to perfusion abnormalities, fatty liver, confluent fibrosis and radiation hepatitis; morphologic changes of the liver; true pseudotumors. The use of multidetector CT and MR imaging increases the likelihood of detecting such lesions in routine practice. Radiologists must recognize these lesions and understand the underlying etiology.

The effect of maternal care on child survival: a demographic, genetic, and evolutionary perspective.

Models of population dynamics generally assume that child survival is independent of maternal survival. However, in humans, the death of a mother compromises her immature children's survival because children require postnatal care. A child's survival therefore depends on her mother's survival in years following her birth. Here, we provide a model incorporating this relationship and providing the number of children surviving until maturity achieved by females at each age. Using estimates of the effect that a mother's death has on her child's survival until maturity, we explore the effect of the model on population dynamics. Compared to a model that includes a uniform child survival probability, our model slightly raises the finite rate of increase lambda and modifies generation time and the stable age structure. We also provide estimates of selection on alleles that change the survival of females. Selection is higher at all adult ages in our model and remains significant after menopause (at ages for which the usual models predict neutrality of such alleles). Finally, the effect of secondary caregivers who compensate maternal care after the death of a mother is also emphasized. We show that allocare (as an alternative to maternal care) can have a major effect on population dynamics and is likely to have played an important role during human evolution.

Unbiased interpretation of haplotypes at duplicated microsatellites.

The Y-chromosome is a powerful tool for population geneticists to study human evolutionary history. Haploid and largely non-recombining, it should contain a simple record of past mutational events. However, this apparent simplicity is compromised by Y-linked duplicons, which make up approximately 35% of this chromosome; 25% of these duplicons are large inverted repeats (palindromes). For microsatellites lying in these palindromes, two loci cannot be easily distinguished due to PCR co-amplification, and this order misspecification of alleles generates an additional variance component. Due to this ambiguity, population geneticists have traditionally used an arbitrary method to assign the alleles (shorter allele to locus 1, larger allele to locus 2). Here, we simulate these posterior estimate distributions under three different novel allele assignment priors and compare this with the original method. We use a sample of 33 human populations, typed for duplicated microsatellites lying within palindrome P8, to illustrate our approach. We show that both intra- and inter-population statistics can be dramatically affected by order misspecification. Surprisingly, matrices of pairwise F-statistics or distance estimates appear far less sensitive to order misspecification and remain relatively unchanged under the priors considered, suggesting that these microsatellites can be considered as useful markers for population genetic studies using an appropriate data treatment. Duplicated microsatellites represent an attractive source of information to investigate the extensive structural polymorphism observed among human Y chromosomes, as well as processes of intra-chromosomal gene conversion acting between duplicons.

Sequential arterial and portal vein embolizations before right hepatectomy in patients with cirrhosis and hepatocellular carcinoma.

BACKGROUND: Selective transarterial chemoembolization (TACE) and portal vein embolization (PVE) could improve the rate of hypertrophy of the future liver remnant (FLR) in patients with chronic liver disease. This study evaluated the feasibility and efficacy of this combined procedure. METHODS: Between November 1998 and October 2004, 36 patients with cirrhosis and hepatocellular carcinoma underwent right hepatectomy after PVE. Additional TACE preceded PVE by 3-4 weeks in 18 patients (TACE+PVE group) and the remaining 18 patients had PVE alone (PVE group). RESULTS: PVE was well tolerated in all patients. The mean increase in percentage FLR volume was significantly higher in the TACE+PVE group than in the PVE group (mean(s.d.) 12(5) versus 8(4) percent; P=0.022). The rate of hypertrophy was more than 10 percent in 12 patients in the TACE+PVE group and in five who had PVE alone (P=0.044). Duration of surgery, blood loss, incidence of liver failure and mortality (two patients in each group) were similar in the two groups. None of the 17 patients with an increase in FLR volume of more than 10 percent died, whereas there were four deaths among 19 patients with a smaller increase. The incidence of complete tumour necrosis was significantly higher in the TACE+PVE group (15 of 18 versus one of 18; P<0.001), with a higher 5-year disease-free survival rate (37 versus 19 percent; P=0.041). CONCLUSION: Sequential TACE and PVE before operation increases the rate of hypertrophy of the FLR and leads to a high rate of complete tumour necrosis associated with longer recurrence-free survival.

Utility of staging laparoscopy in subsets of biliary cancers : laparoscopy is a powerful diagnostic tool in patients with intrahepatic and gallbladder carcinoma.

BACKGROUND: The aim of this study was to evaluate the utility of staging laparoscopy in patients with biliary cancers in the era of modern diagnostic imaging. METHODS: From September 2002 through August 2004, 39 consecutive patients with potentially resectable cholangiocarcinoma underwent preoperative staging laparoscopy before laparotomy. Preoperative imaging included ultrasonography and triphasic computed tomography for all patients and magnetic resonance cholangiography in 35 patients (90%). Final pathological diagnosis included 20 hilar cholangiocarcinomas (HC), 11 intrahepatic cholangiocarcinomas (IHC), and eight gallbladder carcinomas (GBC). RESULTS: During laparoscopy, unresectable disease was found in 14/39 patients (36%). The main causes of unresectability were peritoneal carcinomatosis (11/14) and liver metastases (5/14). At laparotomy, nine patients (37%) were found to have advanced disease precluding resection. Vascular invasion and nodal metastases were the main causes of unresectability during laparotomy (eight out of nine). In detecting peritoneal metastases and liver metastases, laparoscopy had an accuracy of 92 and 71%, respectively. All patients with vascular or nodal involvement were missed by laparoscopy. For prediction of unresectability disease, the yield and accuracy of laparoscopy were highest for GBC (62% yield and 83% accuracy), followed by IHC (36% yield and 67% accuracy) and HC (25% yield and 45% accuracy) CONCLUSION: Staging laparoscopy ensured that unnecessary laparotomy was not performed in 36% of patients with potentially resectable biliary carcinoma after extensive preoperative imaging. In patients with biliary carcinoma that appears resectable, staging laparoscopy allows detection of peritoneal and liver metastasis in one third of patients. Both vascular and lymph nodes invasions were not diagnosed by this procedure. Due to these limitations, laparoscopy is more useful in ruling out dissemination in GBC and IHC than in HC.

[Liver and vascular abnormalities]. / Foie et anomalies de perfusion en imagerie.

The liver is a parenchyma which contains many vessels. They are composed of two inflow vessels: the portal vein and the hepatic artery, and one outflow system represented by the hepatic veins. We will see in the chapter most of the abnormalities and their consequences due to decrease or an increase of the blood flow of these vessels. Many illustrations will be provided with a special focus on CT findings with multiphasic images.

Haemobilia causing acute pancreatitis after percutaneous liver biopsy: diagnosis by magnetic resonance cholangiopancreatography.

Magnetic resonance cholangiopancreatography (MRCP) has received much attention as a non-invasive alternative to endoscopic retrograde cholangiopancreatography, primarily for investigation of choledocholithiasis, but also for evaluation of less common biliary anomalies. We present a case of haemobilia causing acute pancreatitis after percutaneous liver biopsy in which the diagnosis could be made clearly by MRCP, thus avoiding endoscopic retrograde cholangiopancreatography and sphincterotomy.

Helical CT assessment in hilar cholangiocarcinoma: correlation with surgical and pathologic findings.

OBJECTIVE: Our goal was to assess the usefulness of helical CT in the presurgical evaluation of hilar cholangiocarcinoma. CONCLUSION: Helical CT aids in tumor localization and in assessment of parenchymal, biliary intrahepatic, and portal involvement in hilar cholangiocarcinoma. However, helical CT is not effective in the assessment of biliary extrahepatic, arterial, and lymph node involvement.

[Congenital cystic dilatation of the common bile duct. Radio-anatomical correlations in 14 patients]. / Dilatation kystique congénitale de la voie biliaire principale. Corrélations radio-anatomiques chez 14 malades.

OBJECTIVES: The aim of this study was to compare imaging and pathological results of congenital cystic enlargement of the biliary tract to determine the best preoperative management strategy. PATIENTS AND METHODS: Radiological findings of 14 cases treated by surgery were reviewed. Radiological examinations were reviewed: ultrasound (n = 20), computed tomography (n = 13), endoscopic ultrasound (n = 8), endoscopic retrograde cholangiopancreatography (n = 10), percutaneous transhepatic cholangiography (n = 3), peroperative cholangiography (n = 11). Imaging and surgical or pathological correlations were obtained with regard to topographical type using Todani's classification, pancreatobiliary junction, and associated diseases, especially biliary malignancies (cystic wall and gallbladder). RESULTS: Cystic enlargement of the biliary tract was type Ia in 2 patients, type Ib in 1, type Ic in 4, type IVa in 5, and type IVb in 2. The radio-pathological correlation was excellent for the topographical type, and quite good for intrahepatic extension. An abnormal pancreatobiliary junction was identified in 5 cases, and visualized before surgery in I case. This junction was not opacified pre- or pre-operatively in 7 cases. Gallbladder stones were present in 2 cases, choledocal stones, in 2 cases, and intrahepatic stones in one cases, always seen on ultrasound. Malignant degeneration was present in the cyst in one case in the pathological specimen, but was not visualized by imaging procedures or peroperatively; one intrahepatic degeneration was visualized on CT and histologically proven in the surgical specimen. CONCLUSION: Ultrasound and CT allow positive diagnosis of cystic enlargement of the biliary tract, and diagnosis of intrahepatic cyst and associated diseases. The bifurcation extension and the study of pancreatobiliary junction require peroperative or retrograde cholangiography.

[Comparison of scanners and porto-scanners, both in helical mode, for the study of hepatic metastases. Prospective study in 12 patients]. / Comparaison du scanner et du porto-scanner, tous deux en mode hélicoïdal, pour l'étude des métastases hépatiques. Etude prospective chez 12 malades.

PURPOSE: The aim of this study was to compare helical CTAP and helical CT-scan in the preoperative assessment of liver metastases. METHODS: A prospective unicentric study in 12 patients was performed with helical CTAP and helical CT-scan. All patients underwent partial hepatectomy with intraoperative palpation and sonography within 19 days (mean: 9 days). RESULTS: Examination of resected liver specimens found 38 metastases, from colorectal cancer in 36 cases. The sensitivity was 92.1% for helical CTAP and 79% for helical CT-scan. This sensitivity was 85% for helical CTAP and 60% for helical CT-scan for nodules 1 cm or less in diameter (P = 0.08). CONCLUSION: In the preoperative screening of liver metastases, helical CT-scan should be performed as the first choice examination. When hepatic lesions seem to be curable by resection based on helical dynamic CT-scan results, helical CTAP should be performed to increase the sensitivity of detection of lesions 1 cm or less in diameter.

[Imaging of atypical cysts of the liver. Study of 26 surgically treated cases]. / Imagerie des kystes atypiques du foie. Etude de 26 lésions opérées.

OBJECTIVES: Differential diagnosis between a benign cystic hepatic lesion, biliary cyst, and a potentially malignant lesion or biliary cystadenoma, is difficult. The aim of this study was to evaluate imaging features of atypical cystic liver lesions and the role of imaging techniques in determining a specific diagnosis. METHODS: Twenty-six patients with atypical cystic hepatic lesions were included in this study. All patients underwent surgery and pathological diagnosis was atypical hepatic cyst (n = 18), biliary cystadenoma (n = 4), hydatic cyst (n = 3), and ciliated hepatic foregut cyst (n = 1). We systematically reviewed US (n = 24), CT (n = 24), and MRI (n = 8) examinations. RESULTS: Septum were seen in both cystadenomas (US: n = 4, CT: n = 1) and hepatic cysts (US: n = 11, CT: n = 6). No mural nodules were seen. A thin wall was noted in both hepatic cysts (n = 2) and cystadenomas (n = 3). The intrahepatic biliary tract was dilated in 3 patients with hepatic cysts, 1 patient with cystadenoma, and 2 patients with hydatic cysts. Calcifications were noted in 1 patient with hepatic cyst, 3 patients with hydatic cysts, and in the case of ciliated hepatic foregut cyst. We found an associated typical hepatic cyst in 77% of cases (14/18) with atypical hepatic cysts; this was never found in other atypical cystic lesions (P < 0.01). CONCLUSION: In this series, no imaging features provided a differential diagnosis of atypical hepatic cysts and cystadenomas. The presence of associated typical hepatic cysts is helpful in suggesting the diagnosis of hepatic cyst.

Dynamic gadolinium-DOTA-enhanced MR imaging at 1.0 T. Value in the differentiation of hepatic tumors.

A prospective study was performed to determine the value of dynamic gadolinium-tetraazacyclododecane-tetraacetic acid (Gd-DOTA)-enhanced magnetic resonance (MR) imaging at 1.0 T, using a gradient-echo (GRE) technique, in the differentiation of hepatic tumors. Fifty patients with hemangiomas (n = 14), focal nodular hyperplasia (n = 4), and malignant tumors of the liver (n = 32) underwent GRE MR imaging at 1.0 T before and repeatedly for 4 minutes after intravenous bolus administration of Gd-DOTA. The diagnoses were proved by histology or follow-up examination. On unenhanced GRE images, hemangiomas had a significantly lower tumor-to-liver contrast-to-noise (C/N) ratio (-14.74 +/- 4.49) than did the other tumors (-6.96 +/- 5.49) (p < 0.02), and benign tumors had a significantly lower C/N ratio (-12.43 +/- 5.99) than did malignant tumors (-7.29 +/- 5.71) (p < 0.05). On contrast-enhanced images, hemangiomas had a significantly lower C/N ratio (-17.60 +/- 6.90) than did the other tumors (-5.07 +/- 12.12) (p < 0.05) in the early phase. During the delayed phase, hemangiomas had a significantly higher C/N ratio (3.90 +/- 3.81) than did the other tumors (-4.85 +/- 6.51) (p < 0.01), and benign tumors had a significantly higher C/N ratio (3.21 +/- 3.65) than did malignant tumors (-5.56 +/- 6.56) (p < 0.001). Our data suggest that dynamic Gd-DOTA-enhanced MR imaging at 1.0 T provides useful information to differentiate between benign and malignant hepatic tumors, and to distinguish hemangiomas from the other tumors.

[Imaging of pancreatitis]. / Imagerie des pancréatites.

Acute and chronic pancreatitis involve different problems. In acute pancreatitis, the method of choice is CT scan, which provides a precise description of the lesions as a basis for establishing criteria of severity. Discovery of infection often requires scan-guided puncture. For chronic pancreatitis, a greater range of examinations is available. The CT scan is the best noninvasive method. Ultrasound examination can be repeated for follow-up. Echoendoscopy shows early signs. Excellent diagnostic results are provided by retrograde endoscopic cholangiopancreatography. It is indispensable for the presurgery work-up and sometimes for differential diagnosis of cancer.