MRI for characterization of benign hepatocellular tumors on hepatobiliary phase: the added value of in-phase imaging and lesion-to-liver visual signal intensity ratio.

OBJECTIVES: To evaluate the lesion-to-liver visual signal intensity ratio (SIR) before and at the hepatobiliary phase MRI (HBP-MRI) after gadobenate dimeglumine (Gd-BOPTA) injection, using several T1-weighted images (T1-WI), for the characterization of benign hepatocellular lesions. METHODS: Patients with histologically proven focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA), who underwent Gd-BOPTA-enhanced HBP-MRI from 2009 to 2017, were retrospectively identified. The lesion-to-liver SIR was visually assessed by two radiologists on HBP (post-HBP analysis) and compared with that of unenhanced sequences (pre/post-HBP analysis) on T1-WI in-phase (T1-IP), out-of-phase (T1-OP), and fat suppression (T1-FS). Lesions were classified as hyper-, iso-, or hypointense on post-HBP, and as decreasing, stable, or increasing SIR on pre/post-HBP analyses. The performance of the different T1-WI sequences for the diagnostic of FNH was evaluated on post-HBP analysis. RESULTS: Twenty-nine FNHs and 33 HCAs were analyzed. On post-HBP analysis, FNHs appeared hyper-/isointense in 89.7% of all T1-WI. HCAs appeared hypointense in 93.9%, 63.6%, and 69.7% of T1-IP, T1-OP, and T1-FS, respectively. FNHs exhibited an increasing SIR in 55.2-58.6%, a stable SIR in 44.8-58.6%, and a decreasing SIR in 0%, whereas HCAs exhibited a decreasing SIR in 66.7-93.9%, a stable SIR in 6.1-33.3%, and an increasing SIR in 0% (p < 0.0001). The specificity of T1-IP was significantly higher than that of T1-OP (p = 0.015) and T1-FS (p = 0.042). CONCLUSION: T1-IP is the most reliable sequence due to misleading tumor/liver signal ratio in the case of fatty liver when using T1-FS or T1-OP. The pre/post-HBP lesion-to-liver SIR is accurate to classify benign hepatocellular lesions and contributes to avoid biopsy. KEY POINTS: •The T1-weighted images in-phase should be systematically included in the HBP-MRI protocol, as it is the most reliable sequence especially in the case of fatty liver. •The comparison between lesion-to-liver signal intensity ratios on unenhanced and at the hepatobiliary phase sequences is useful to classify benign hepatocellular lesions in three categories without misclassification: FNH (increasing signal intensity ratio), HCA (decreasing signal intensity ration), and indeterminate lesions (stable signal intensity ratio).

Imaging features, complications and differential diagnoses of abdominal cystic lymphangiomas.

PURPOSE: The aim of the study is to describe the imaging features, complications and differential diagnoses of abdominal cystic lymphangiomas (ACLs). RESULTS: ACLs are benign lymphatic malformations that mainly arise in the subperitoneal space and the retroperitoneum. The typical presentation of an ACL is a multilocular lesion with homogenous serous content, presenting a thin wall and septa, usually free from adjacent organ compression. Atypical findings, including fat or hemorrhagic content, septal calcifications and unilocular presentation, are not uncommon. Rarely, ACLs can be revealed by acute complications, such as infection, hemorrhage, intussusception, complications with a twisting mechanism (including torsion around its own pedicle) or spontaneous rupture, which can be diagnosed by imaging. Ultrasonography and CT are the most useful modalities in emergency situations. MRI performs best in the noninvasive characterization of cystic lesions. ACLs should be differentiated from normal anatomic structures (e.g., cisterna chyli) or pitfalls (e.g., ascites, extrapancreatic necrosis, lymphocele) that can simulate ACLs. Among other primary peritoneal cystic lesions, benign cystic mesothelioma can be difficult to differentiate from ACL. Some neoplastic peritoneal lesions may have cystic components or content that looks like fluid on imaging (such as mucinous or myxoid content) and be misdiagnosed as ACL. Nodular or thick enhancement of the wall or septa should then be considered worrisome features and should not suggest ACL. ACLs mostly require a simple follow-up. If treatment is necessary, percutaneous sclerotherapy is a safe and effective alternative to surgery. CONCLUSION: Imaging, especially MRI, allows the noninvasive diagnosis of ACL and helps to exclude potential malignant differential diagnoses.

Acquired diverticular disease of the jejunum and ileum: imaging features and pitfalls.

PURPOSE: To present radiological aspects of jejunoileal diverticulosis and its complications. RESULTS: Jejunoileal diverticulosis is a relatively rare and underestimated condition, which mostly affects the elderly. It is frequently asymptomatic but it can lead to significant complications requiring surgical treatment. Jejunoileal diverticulosis is far less common than colonic diverticulosis. Acquired small bowel diverticula are often numerous but the complication rate is low. Acute diverticulitis is the most frequent complication; its classic presentation involves the jejunum and is often non-severe. Diverticular hemorrhage is the second most common complication; CT scan examination is essential to determine the accurate topography of the pathological diverticula. Small bowel obstruction can occur through several mechanisms: adhesions, enterolith, and intussusception. Extra-intestinal gas without perforation and "pseudo-ischemic" appearance are non-pathological conditions that are important to diagnose in order to avoid surgery. CONCLUSION: Jejunoileal diverticulosis usually does not show any symptoms but can lead to diagnostic challenges requiring evaluation by CT. CT scan signs of these complications and some pitfalls must be known.

Ranitidine kinetics and dynamics. I. Oral dose studies.

Ranitidine, an H2-receptor antagonist, has been shown to reduce pentagastrin-stimulated gastric secretion. We examined the relationship between inhibition of gastric secretion and ranitidine serum concentration. Twelve normal male subjects received 20, 40, or 80 mg of ranitidine orally 90 min before starting a 3-hr continuous infusion of pentagastrin, 2 micrograms/kg/hr. Ranitidine, 20, 40, and 80 mg, reduced hydrogen ion output by 29%, 50%, and 70% and secretion volume by 21%, 37%, and 47%. Pepsin activity was reduced by 8%, 50%, and 49% by the same doses. Peak serum concentration was correlated positively with percent reduction in hydrogen ion output (r = 0.81, P less than 0.001) and volume (r = 0.71, P less than 0.01) over a 2-hr period. A 50% inhibition of hydrogen ion output was associated with a peak ranitidine serum concentration of 165 micrograms/l and subjects reached peak serum concentration 60 to 120 min after oral dosing. An appropriate therapeutic effect should be achieved with 8 hourly doses of 80 mg ranitidine. No clinically significant subjective or toxic biochemical effect of ranitidine was seen after single doses. White blood cell count was reduced in 11 of 12 subjects 7 days after ranitidine, an observation which calls for further investigation.

Ranitidine kinetics and dynamics. II. Intravenous dose studies and comparison with cimetidine.

Intravenous ranitidine has been shown to reduce pentagastrin-stimulated gastric secretion. Eight normal men received, in randomized order, 60 mg ranitidine or 300 mg cimetidine intravenously over 2 min. Both ranitidine and cimetidine induced decreases in volume hydrogen ion content and pepsin activity of stimulated gastric juice. Ranitidine half-life (t1/2) was 2.1 +/- 0.1 hr and cimetidine (t1/2) was 1.5 +/- 0.1 hr. Ranitidine volume of distribution was 1.6 +/- 0.1 l/kg and that of cimetidine was 1.12 +/- 0.12 l/kg. The clearance of ranitidine was 0.54 +/- 0.04 l/kg hr-1 and that of cimetidine was 0.5 +/- 0.05 l/kg hr-1. It is suggested that the intravenous loading dose of ranitidine necessary to attain a serum concentration of 200 micrograms/l (which would achieve a 50% inhibition of gastric acid) is 0.3 mg/kg, followed by an infusion rate of 0.11 mg/kg hr-1.

[Is the identification of acute biliary and alcoholic pancreatitis by early pancreatic enzyme assay possible?]. / L'identification des pancréatites aiguës biliaires et alcooliques par le dosage précoce des enzymes pancréatiques est-elle possible?

Early and appropriate treatment of acute pancreatitis (AP) depends on early causal diagnosis. Published studies have shown favourable results following sphincterotomy performed within the 72 hours of onset of severe gallstone-associated AP. Among the various bio-clinical indices, the lipase/amylase (L/A) ratio, computed within 72 hours after onset, has been shown to discriminate between alcoholic and non alcoholic AP. Our study evaluates the data of biochemical disorders in 51 patients presenting with an episode of AP; these patients were divided into 3 groups: A: alcoholic AP, n = 15; B: biliary AP, n = 25; and C: post-ERCP AP, n = 11. These 3 groups were similar with respect to clinical severity of AP and CT scan. The time delays between onset of the symptoms and the biochemical assay were 1.9 +/- 0.3, 1.9 +/- 0.2 and 0.6 +/- 0.3 d (P < 0.01). AST, ALT, bilirubin, GGT and alkaline phosphatase were significantly (P < 0.05) greater in group B. Blamey's score was 0.5 +/- 0.2, 2.8 +/- 0.2 and 2.5 +/- 0.4 in groups A, B and C respectively. Serum amylase, serum lipase and L/A ratio were identical in groups A and B. The decrease in serum amylase after 48 hours was more important only in group B (56 +/- 8, 80 +/- 4, 47 +/- 3% respectively in groups A, B and C). L/A ratio was significantly greater in group C when compared with group A and B (1.7 +/- 0.4, 1.5 +/- 0.2 and 2.2 +/- 0.3 in groups A, B and C respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

[Action of imipenem on Enterobacter cloacae]. / Etude de l'action de l'imipénème sur Enterobacter cloacae.

Most of Enterobacter cloacae strains produce chromosomally determined class I beta-lactamases when they are exposed to beta-lactams. Imipenem is a strong inducer of these enzymes but is poorly affected by them. We compared the effect of imipenem on inducible, non-inducible and stably derepressed strains of E. cloacae using the killing curve system. With antibiotic concentrations of 0.5 mg/l or more, an intense dose-dependent bactericidal effect was observed within 4 to 6 hours. However the bactericidal activity was incomplete. With an inoculum as low as 10(5) bacteria/ml a regrowth was observed after 24 hours. Among the surviving bacteria imipenem had the same bactericidal kinetic than on the parental strain. Similar results were observed with inducible, non-inducible and stably derepressed strains.

Analysis of ranitidine in serum by high performance liquid chromatography.

We describe a simple and rapid micro method for the high pressure liquid chromatographic analysis of ranitidine, N-[2[[[5-[(dimethylamino)-methyl]-2-furanyl]methyl]thio]-ethyl-N'-methyl-2-nitro-1,1-ethenediamine in serum or plasma. The percentage analytical recovery of ranitidine and internal standard (metiamide) was 99% and 81%, respectively. The between-day precision of the procedure (n = 20) at ranitidine plasma concentrations of 500, 250, and 125 microgram/liter generated coefficients of variation of 6.2, 8.7, and 8.9%, respectively. The method was applied in preliminary studies to correlate serum concentrations of ranitidine with gastric acid secretion after continuous pentagastrin stimulation (2 microgram/kg/hr) in patients receiving an oral dose of 20, 40, or 80 mg of the drug.

Serum increase and liver overexpression of carbohydrate 19.9 antigen in patients with genetic haemochromatosis.

CA 19.9 antigen is mainly secreted by biliary and pancreatic duct cells. Its metabolism could be modified in genetic haemochromatosis by iron accumulation within these cells. Therefore, CA 19.9 was assayed in the serum samples of 84 patients with genetic haemochromatosis before and after iron depletion and immunolocalised in the liver of 24 untreated genetic haemochromatosis cases. The study showed that serum CA 19.9 (N < 37 IU/l) was increased (SD) before treatment (41.2 (34)) when compared with after the venesection period (16 (12)), and correlated, before treatment, with the amount of iron excess, transaminases, fibrosis, and biliary iron deposits. Hepatic CA 19.9 was located within the cytoplasm of bile duct and cholangiolar cells. In conclusion, this study shows that a mild, reversible, and non-specific increase in serum CA 19.9 is common in genetic haemochromatosis patients and shows that this increase is related to iron excess, directly or through associated liver damage. The unexplained finding of a mild increase in serum CA 19.9 should lead, in a patient with no diagnosis, to the search for liver iron overload, and, in a patient with untreated genetic haemochromatosis, not to further diagnostic procedures unless this finding persists after completion of the venesection treatment.

Latex allergy: epidemiological study of 1351 hospital workers.

OBJECTIVE: To determine the prevalence of latex sensitisation among a large group of healthcare workers, study the occupational and non-occupational factors associated with latex allergy, and characterise latex exposure in air and by gloves. METHODS: All 2062 employees of a general hospital in Hamilton, Ontario, Canada who regularly used latex gloves were invited to participate in a cross sectional survey, representing the baseline phase of a prospective cohort morbidity study. Attempts were made to recruit employees who were diagnosed with latex allergy before the survey. Glove extracts were assayed for antigenic protein, and area and personal air samples were obtained on two occasions (summer and winter) to estimate exposure to airborne latex protein. A questionnaire on medical and occupational information was administered by an interviewer. Skin prick tests were performed with latex reagents, three common inhalants, and six foods. RESULTS: The mean (SD) latex protein concentrations were 324 (227) micrograms/g in powdered surgical gloves and 198 (104) micrograms/g in powdered examination gloves. Personal latex aeroallergen concentrations ranged from 5 to 616 ng/m3. There was a total of 1351 (66%) participants. The prevalence of positive latex skin tests was 12.1% (95% confidence interval (95% CI) 10.3% to 13.9%). This prevalence did not vary by sex, age, hospital, or smoking status but subjects who were latex positive were significantly more likely to be atopic (P < 0.01). Participants who were latex positive were also significantly more likely to have positive skin tests to one or more foods (Mantel-Haenszel odds ratio (OR) adjusted for atopy 12.1, 95% CI 7.6 to 19.6, P < 10(-9)). Work related symptoms were more often reported among latex positive people, and included hives (OR 6.3, 95% CI 3.2 to 12.5), eye symptoms (OR 1.9, 95% CI 1.2 to 2.8), and wheezy or whistling chest (OR 4.7, 95% CI 2.8 to 7.9). The prevalence of latex sensitivity was highest among laboratory workers (16.9%), and nurses and physicians (13.3%). When the glove consumption per healthcare worker for each department was grouped into tertiles, the prevalence of latex skin test positivity was greater in the higher tertiles of glove use for sterile (surgical) gloves (P < 0.005) but not for examination gloves. CONCLUSIONS: In this large, cross sectional study of healthcare workers, the prevalence of latex sensitisation was 12.1% (9.5% among all those eligible), and there were significant associations with atopy, positive skin tests to certain foods, work related symptoms, and departmental use of gloves per healthcare worker. This cohort is being followed up prospectively and will be retested to determine the incidence of development of latex sensitivity.

Incidence of latex sensitization among latex glove users.

BACKGROUND: Although there are several reports of the prevalence of latex sensitization among health care workers, the incidence of sensitization is unknown. OBJECTIVE: The objective of this study was to estimate the incidence of sensitization among latex glove users at a hospital in Hamilton, Ontario, Canada. METHODS: Workers with negative results to the skin test at baseline were followed prospectively over 1 year, some wearing powdered gloves and others using powder-free gloves. They were reevaluated in 1995 with a questionnaire and skin prick test (SPT) sensitivity to latex reagents, three common inhalants, and six foods. A conversion was defined as a (new) latex SPT with wheal diameter at least 4 mm greater than saline control. Glove extracts were assayed for antigenic protein, and air samples were obtained to estimate exposure to airborne latex protein. RESULTS: During powdered glove use, personal exposures ranged from 5 to 616 ng/m3, whereas during powder-free glove use, all but two results for air samples were below the limit of detection (about 0.1 ng/m3). During the study period, the protein concentration in the powdered gloves, initially mean 557 microg/gm of sample, declined at a rate of 295 microg/gm per year (p < 0.0001). Of the 1075 SPT-negative participants at baseline, 479 were working in eligible wards, and of these, 435 (91%) participated in follow-up, 227 using powder-free gloves and 208 using powdered gloves. We identified four conversions, two (1.0%) in the powdered glove group and two (0.9%) in the powder-free group. The two participants using powdered gloves were the only converters who were symptomatic. The significance of skin test conversions identified in the powder-free group, both asymptomatic patients, is unclear. The limitations of the study are discussed, including the limited power, the declines in latex protein concentrations, and the possibility of information (observer) bias. CONCLUSION: To our knowledge, this represents the first reported estimate (about 1%) of incidence of sensitization in hospital personnel using latex gloves.