Test-positive rate at CT colonography is increased by rectal bleeding and/or unexplained weight loss, unlike other common gastrointestinal symptoms.

PURPOSE: We evaluated the rate of significant colonic and extra-colonic abnormalities at computed tomography colonography (CTC), according to symptoms and age. MATERIALS AND METHODS: We retrospectively evaluated 7361 consecutive average-risk subjects (3073 males, average age: 60.3 ± 13.9; range 18-96 years) for colorectal cancer (CRC) who underwent CTC. They were divided into three groups according to clinical symptoms: 1343 asymptomatic individuals (group A), 899 patients with at least one "alarm" symptom for CRC, including rectal bleeding and unexplained weight loss (group C), and 5119 subjects with other gastrointestinal symptoms (group B). Diagnostic and test-positive rates of CTC were established using optical colonoscopy (OC) and/or surgery as reference standard. In addition, clinically significant extra-colonic findings were noted. RESULTS: 903 out of 7361 (12%, 95% confidence interval (CI) 0.11-0.13) subjects had at least one clinically significant colonic finding at CTC. CTC true positive fraction and false positive fraction were respectively 637/642 (99.2%, 95%CI 0.98-0.99) and 55/692 (7.95%, 95%CI 0.05-0.09). The pooled test-positive rate in group C (138/689, 20.0%, 95%CI 0.17-0.23) was significantly higher than in both groups A (79/1343, 5.9%, 95%CI 0.04-0.07) and B (420/5329, 7.5%, 95%CI 0.07-0.08) (p < 0.001). Aging and male gender were associated to a higher test positive rate. The rate of clinically significant extra-colonic findings was significantly higher in group C (44/689, 6.4%, 95%CI 0.04-0.08) versus groups A (26/1343, 1.9%, 95%CI 0.01-0.02) and B (64/5329, 1.2%, 95%CI 0.01-0.02) (p < 0.001). CONCLUSION: Both test-positive and significant extra-colonic finding rates at CTC are significantly increased in the presence of "alarm" gastrointestinal symptoms especially in older patients.

Screening for colorectal cancer in asymptomatic average risk patients: role of imaging.

Early detection of colorectal cancer or advanced adenomas is a public health priority in many industrialized countries. There are various methods of screening average risk individuals for colorectal cancer, and their effectiveness may depend on subjective parameters like local expertise and patient's preferences. This paper reviews these tests with special emphasis regarding imaging techniques that aim to provide less-invasive alternatives to optical colonoscopy (OC) which is the standard of reference. Both Double-Contrast Barium Enema (DCBE) and Virtual Colonoscopy (VC) have >90% sensitivity compared to OC in the detection of clinically relevant colonic lesions. Nevertheless, VC may have an edge over DCBE for technical and reproductivity reasons, as well as greater learning opportunities. Imaging techniques criticisms regarding diminutive and flat lesions, cost, radiation exposure and effects on gastroenterological practice are addressed.

Adrenal ganglioneuroma. A neoplasia to exclude in patients with adrenal incidentaloma.

OBJECTIVE: To determinate the MRI and CT scanning appearance of adrenal ganglioneuroma and correlate the imaging with histological features. SUMMARY BACKGROUND DATA: In the last 10 years, eight patients with a pathologically proven adrenal ganglioneuroma were operated on in our department of endocrine surgery. To our knowledge, these patients represent one the largest reported cohorts of adrenal ganglioneuroma treated in a single institution. METHODS: All these eight patients had a comprehensive hormonal work up and underwent CT and/or MRI. Biological data, radiological features and histological findings were thoroughly reviewed in order to further characterize these tumours. RESULTS: The most relevant characteristics of adrenal GN resected in our patients were: No hormonal hypersecretion, Presence of calcifications; no vessel involvement; and a non-enhanced attenuation of less than 40 HU on CT, A low non-enhanced T1W signal, a slightly high and heterogeneous T2W signal, a late and gradual enhancement on dynamic MRI, especially if associated with a whorled pattern. CONCLUSIONS: Even if many aggressive tumours, mainly adrenal carcinoma, may share some of these radiological features, the presence of all or most of them must made the clinician evoke the diagnosis of GN.

[Chronotherapy combining 5-fluorouracil, folinic acid and carboplatin as first line treatment in metastatic colorectal cancer. A phase 2 study]. / Chronothérapie associant le 5-fluorouracile, l'acide folinique, et le carboplatine en première ligne thérapeutique dans le cancer colorectal métastatique. Une étude de phase 2.

Seventy-two patients suffering from a metastatic colorectal cancer received, as first line treatment, a combination chronotherapy with 5-FU and folinic acid (infused from 10 pm to 10 am with a peak at 4 am, respectively at doses of 700 and 300 mg/m2 per day) and carboplatin (infused at the dose of 40 mg/m2 per day from 10 am to 10 pm with a peak at 4 pm). The courses of four days were repeated every two weeks. A major tumoral response was observed in 60% cases (68% in those not previously treated with adjuvant chemotherapy). The median times to progression and overall survival established at 11 and 27 months. The clinical (grades 3-4 in maximum 5% cases) and hematological (grades 3-4 in maximum 10-29% cases) toxicities were quite limited. Our observations suggest the interest to incorporate carboplatin in the combined infusional treatment of colorectal cancer.

[Stepping-table MR angiography of the upper limb arteries]. / L'angio-IRM en plusieurs stations des artères des membres supérieurs.

Stepping-table MR angiography of the upper limb arteries is reported in a patient with clinical and sonographic signs of ischemia. Advantages and limitations of the technique are discussed.

Assessment of hepatic perfusion parameters with dynamic MRI.

Quantification of hepatic perfusion parameters greatly contributes to the assessment of liver function. The purpose of this study was to describe and validate the use of dynamic MRI for the noninvasive assessment of hepatic perfusion parameters. The signal from a fast T(1)-weighted spoiled gradient-echo sequence preceded by a nonslice-selective 90 degrees pulse and a spoiler gradient was calibrated in vitro with tubes filled with various gadolinium concentrations. Dynamic images of the liver were obtained after intravenous bolus administration of 0.05 mmol/kg of Gd-DOTA in rabbits with normal liver function. Hepatic, aortic, and portal venous signal intensities were converted to Gd-DOTA concentrations according to the in vitro calibration curve and fitted with a dual-input one-compartmental model. With MRI, hepatic blood flow was 100 +/- 35 mL min(-1) 100 mL(-1), the arterial fraction 24 +/- 11%, the distribution volume 13.0 +/- 3.7%, and the mean transit time 8.9 +/- 4.1 sec. A linear relationship was observed between perfusion values obtained with MRI and with radiolabeled microspheres (r = 0.93 for hepatic blood flow [P < 0.001], r = 0.79 for arterial blood flow [P = 0.01], and r = 0.91 for portal blood flow [P < 0.001]). Our results indicate that hepatic perfusion parameters can be assessed with dynamic MRI and compartmental modeling.

Value of multislice helical CT scans and maximum-intensity-projection images to improve detection of ureteral stones at abdominal radiography.

OBJECTIVE: The purpose of this study was to assess the improvement in the detection of ureteral stones on abdominal radiographs when the stones were viewed on multislice helical CT scans and maximum-intensity-projection (MIP) images. SUBJECTS AND METHODS: The study included 72 patients with renal colic who underwent abdominal radiography and multislice helical CT. For each patient, a frontal MIP image was generated, and the stone, when present, was marked with a cross on the transverse CT scan. The cross appeared automatically on the corresponding MIP image. The CT examination was used as the standard of reference. The presence and location of ureteral stones on the abdominal radiographs were assessed during three interpretation sessions. In the first session, the abdominal radiographs were viewed alone. In the second, they were viewed with the transverse CT scans. In the third, the abdominal radiographs were viewed with the CT scans and the MIP images. RESULTS: Ureteral stones were present in 58 patients. The percentage of stones detected on the abdominal radiographs was 45% when the radiographs were viewed alone, 66% when they were viewed with the CT scans (p = 0.002 vs radiographs alone), and 78% when viewed with the CT scans and MIP images (p = 0.016 vs radiographs with CT scans). CONCLUSION: The sensitivity of stone detection on abdominal radiographs was greatest when the interpreters viewed the radiographs in conjunction with the CT scans and MIP images.

The surgical management of congenital liver cysts.

BACKGROUND: Most series that report the results of surgical treatment for congenital liver cysts focus more on the technical aspects of the operation than on the late outcome of these patients. In this paper, we emphasize the importance of appropriate patient selection and adequate surgical technique for successful long-term outcome. METHODS: Twenty-four consecutive patients with congenital liver cysts were selected for surgical treatment. According to our own classification, 13 patients had simple liver cysts, nine had multicystic liver disease, and two had type I polycystic liver disease. All of these patients were treated by the fenestration technique. An open approach was used for five patients (group 1) treated between 1984 and 1990. In 19 patients (group 2) treated since 1991, a laparoscopic approach was used. The incidence of complicated liver cysts was 40% in group 1 and 68% in group 2. RESULTS: There were no treatment-related deaths in this series. The mean postoperative hospital stay was significantly shorter for patients who underwent successful laparoscopic fenestration (p < 0.05). In the open group (group 1), there were no postoperative complications, and all patients were alive and free of symptoms during a mean follow-up of 130 months, without any sign of cyst recurrence. In the laparoscopic group (group 2), four patients were converted to open surgery. One of these patients had an inaccessible posterior cyst; another had bile within the cystic cavity. A further two cases had complicated liver cysts with an uncertain diagnosis between congenital and neoplastic cysts. Four patients (21%) developed peri- or postoperative complications. During a mean follow-up time of 38.5 months, none of the patients with simple liver cysts incurred late symptoms or signs of cyst recurrence. In the six patients with multicystic liver disease, one developed disease-related cyst progression (17%) and required reoperation. One of the two patients with type I polycystic liver disease (50%) developed asymptomatic disease-related cyst progression. CONCLUSIONS: When patients are carefully selected and a proper surgical technique is employed, excellent long-term results with a low morbidity rate can be achieved in patients with congenital liver cysts. Patients with multicystic liver disease or type I polycystic liver disease are more prone to late cyst recurrence. A tailored approach is thus indicated for patients with congenital liver cystic disease. However, the laparoscopic approach appears to be the gold standard for the treatment of highly symptomatic or complicated simple liver cysts.

Biodistribution of ultrasmall iron oxide particles in the rat liver.

Ferumoxtran, an ultrasmall superparamagnetic iron oxide particle, can be located in several tissue compartments in the liver, namely the extracellular space (blood and interstitium), reticuloendothelial cells, and possibly hepatocytes. To better understand the compartmental distribution of ferumoxtran in the liver, we performed a longitudinal study in the rat using microscopy and magnetic resonance imaging. At light microscopy, no substantial cellular uptake of ferumoxtran was observed before one hour after injection. With a dose of 15 micromol Fe/kg, the number of ferumoxtran particles in the reticuloendothelial cells peaked between one and four hours and with a 150 micromol Fe/kg dose, it peaked between eight and 24 hours. Within hepatocytes, only sparse particles were observed with electron microscopy, at a dose of 150 micromol Fe/kg. Imaging performed up until one hour after ferumoxtran injection showed a significant increase in liver signal intensity on T1-weighted images. These results suggest that ferumoxtran mainly acts as an extracellular agent for at least one hour in the rat and that reticuloendothelial accumulation peaks at later time points. Substantial uptake within hepatocytes did not occur.

Hepatic perfusion parameters in chronic liver disease: dynamic CT measurements correlated with disease severity.

OBJECTIVE: The aim of our study was to determine if hepatic perfusion parameters measured with CT change in relation to disease severity in patients with chronic liver disease. SUBJECTS AND METHODS: Dynamic contrast-enhanced single-section CT scans of the liver were obtained in 40 individuals who included six control subjects, 16 patients with noncirrhotic chronic liver disease, and 18 patients with cirrhosis. Hepatic, aortic, and portal venous time-density curves were fitted to a dual-input one-compartment model to calculate the liver perfusion, arterial fraction, distribution volume, and mean transit time. RESULTS: Liver perfusion decreased in patients with cirrhosis (67 +/- 23 mL. min(-1). 100 mL(-1) versus 108 +/- 34 mL. min(-1). 100 mL(-1) in control subjects [p = 0.009] and 98 +/- 36 mL. min(-1). 100 mL(-1) in patients with noncirrhotic chronic liver disease [p = 0.003]), and the arterial fraction and the mean transit time increased (41 +/- 27% and 51 +/- 79 sec versus 17 +/- 16% and 16 +/- 5 sec in control subjects, and 19 +/- 6% and 17 +/- 8 sec in patients with noncirrhotic chronic liver disease [p < 0.05]). A significant correlation was seen between these three perfusion parameters and the severity of chronic liver disease based on clinical and biologic data (p < 0.001). No significant change in distribution volume was observed. CONCLUSION: Hepatic perfusion parameters measured with CT were significantly altered in cirrhosis and correlated with the severity of chronic liver disease.

Non-invasive quantification of liver perfusion with dynamic computed tomography and a dual-input one-compartmental model.

Various liver diseases lead to significant alterations of the hepatic microcirculation. Therefore, quantification of hepatic perfusion has the potential to improve the assessment and management of liver diseases. Most methods used to quantify liver perfusion are invasive or controversial. This paper describes and validates a non-invasive method for the quantification of liver perfusion using computed tomography (CT). Dynamic single-section CT of the liver was performed after intravenous bolus administration of a low-molecular-mass iodinated contrast agent. Hepatic, aortic and portal-venous time-density curves were fitted with a dual-input one-compartmental model to calculate liver perfusion. Validation studies consisted of simultaneous measurements of hepatic perfusion with CT and with radiolabelled microspheres in rabbits at rest and after adenosine infusion. The feasibility and reproducibility of the CT method in humans was assessed by three observers in 10 patients without liver disease. In rabbits, significant correlations were observed between perfusion measurements obtained with CT and with microspheres (r=0.92 for total liver perfusion, r=0.81 for arterial perfusion and r=0.85 for portal perfusion). In patients, total liver plasma perfusion measured with CT was 112+/-28 ml.min(-1).100 ml(-1), arterial plasma perfusion was 18+/-12 ml.min(-1).100 ml(-1) and portal plasma perfusion was 93+/-31 ml.min(-1).100 ml(-1). The measurements obtained by the three observers were not significantly different from each other (P>0.1). Our results indicate that dynamic CT combined with a dual-input one-compartmental model provides a valid and reliable method for the non-invasive quantification of perfusion in the normal liver.

Gadolinium-enhanced arterial-phase MR imaging of hypervascular liver tumors: comparison between tailored and fixed scanning delays in the same patients.

The purpose of this study was to compare in the same patients tailored and fixed scanning delays during gadolinium-enhanced arterial-phase magnetic resonance imaging of hypervascular liver tumors. Tailored scanning delays were obtained with automated region of interest threshold triggering. A delay of 23 seconds between the start of contrast material injection and imaging was used for fixed delay examinations. Quantitative and qualitative evaluation was performed in 21 patients with normal cardiac function referred for MR assessment of hypervascular liver tumors. In the tailored examinations, the median time delay between the start of contrast material injection and the start of magnetic resonance imaging was 21 seconds (range, 18-34 seconds). The median tumor-to-liver contrast during tailored examinations was 19.1 versus 14.7 during fixed delay examinations. This difference, however, was not significant. Similarly, the enhancement in the aorta, the portal vein, the liver, and the tumor did not differ significantly between examinations performed with tailored and fixed delays. It is concluded that in our group of patients with hypervascular liver tumors and normal cardiac function, no significant improvement in tumor-to-liver contrast and enhancement during the arterial phase was found when gadolinium-enhanced magnetic resonance imaging was performed with a tailored scanning delay rather than with a fixed delay.

Pancreaticopleural fistula: diagnosis with magnetic resonance pancreatography.

Pancreaticopleural fistula secondary to chronic pancreatitis is a rare cause of recurrent pleural effusion. The demonstration of the fistula with endoscopic retrograde pancreatography and CT is invasive or limited. We report in two patients the use of magnetic resonance pancreatography as a noninvasive alternative to endoscopic retrograde pancreatography for the diagnosis of pancreaticopleural fistula.

Focal nodular hyperplasia: natural course observed with CT and MRI.

PURPOSE: The purpose of this work was to assess the natural course of biopsy-proven focal nodular hyperplasia (FNH). METHOD: Eighteen biopsy-proven FNHs in 14 patients (12 women and 2 men) who were followed for at least 6 months with CT and/or MRI were included in the study. The volume of the lesions was calculated twice by two observers using the summation of areas method. Intra- and interobserver variability was assessed by intraclass correlation coefficients. Longitudinal data analysis was performed with generalized estimating equations. RESULTS: The volume of FNH was stable in 6 cases, decreased in 10 cases, and increased in 2 cases. Intra- and interobserver variability in size measurements was 5-10%. Intraclass correlation coefficients were >0.992. Longitudinal data analysis showed that there was a general trend of lesion regression. CONCLUSION: Long-term follow-up and objective measurements performed in patients with biopsy-proven lesions show that the natural course of FNH is variable. In particular, lesion regression is not rare.

Extrahepatic biliary obstruction: magnetic resonance imaging compared with endoscopic ultrasonography.

BACKGROUND AND STUDY AIMS: The aim of this study was to compare prospectively the diagnostic efficacy of magnetic resonance (MR) imaging and endoscopic ultrasonography (EUS) in extrahepatic biliary obstruction. PATIENTS AND METHODS: A total of 50 patients with suspected benign or malignant extrahepatic biliary obstruction underwent MR imaging, including MR cholangiopancreatography, and EUS, within a median time delay of 1 day. The final diagnosis was established by endoscopic retrograde cholangiopancreatography in 37 cases, intraoperative cholangiography in nine cases, and clinical and biochemical follow-up in four cases. RESULTS: In total, 33 patients had extrahepatic biliary obstruction, of benign origin in 21 cases and of malignant origin in 12 cases, whereas 17 had no evidence of obstruction. The sensitivity and specificity of MR imaging were 91% and 94 %, respectively. There were one false-positive and three false-negative results, all related to choledochal sludge. The corresponding values for EUS were 97% and 88%. There were two false-positive results and one false-negative result. False-positive diagnoses were related to the presumed presence of biliary sludge and choledocholithiasis, whereas the false-negative diagnosis occurred in one patient with a final diagnosis of sludge. No significant difference in sensitivity and specificity was observed between the two imaging methods (P>0.05). CONCLUSION: In our study MR imaging was as accurate as EUS in the diagnosis of extrahepatic biliary obstruction.

MR imaging of hypervascular liver tumors: timing optimization during the arterial phase.

To analyze the optimal timing strategy for the detection of hypervascular liver tumors during the arterial phase of magnetic resonance (MR) imaging, a test examination after injection of 2 mL of gadopentetate dimeglumine was performed in 47 patients. The time course of the tumor-to-liver contrast-to-noise ratio (CNR) for all studies together was determined relative to the start of injection, the time of peak aortic enhancement, and the time of peak enhancement in the tumor. All studies were grouped together and the highest CNR was transiently observed at the time of peak tumor enhancement. This CNR was significantly higher than those observed at fixed delays after peak aortic enhancement. However, the CNRs at peak tumor enhancement+/-1.5 seconds did not differ significantly from those obtained after peak aortic enhancement. Finally, the CNRs obtained at fixed delays after the start of injection remained significantly lower. In hypervascular liver tumors, a higher CNR can be obtained during the arterial phase when the MR imaging delay is determined relative to the time of peak enhancement in the tumor or the aorta rather than being fixed after the start of contrast material injection. Timing based on the enhancement profile in the tumor rather than in the aorta should be performed only if rapid MR imaging is available with a time resolution of about 1.5 seconds to image the whole liver.