CT colonography before colonoscopy in subjects with positive faecal occult blood test. Preliminary experience

PURPOSE

We report a preliminary evaluation of the performance of computed tomography colonography (CTC) systematically obtained before optical colonoscopy (OC) in subjects with positive faecal occult blood test (FOBT) within a population-based screening programme for colorectal cancer (CRC).

MATERIALS AND METHODS

Seventy-nine subjects with positive FOBT from a regional screening programme were invited to perform same day CTC and OC. CTC was performed with standard bowel preparation. OC with segmental unblinding was the reference standard. A per-patient per-adenoma analysis was performed.

RESULTS

Forty-nine of 79 subjects (62%) with positive FOBT adhered to the study and completed both examinations. Twenty-two (44.9%) of the 49 had a cancer or an adenoma ≥6 mm. Per-patient sensitivity, specificity, negative predictive value and positive predictive value for cancer or adenoma ≥6 mm were 95.5% (95%CI:77.2%-99.9%), 51.9% (95%CI:32.0%-71.3%), 93.3% (95%CI:68.1%-99.8%) and 61.8% (95%CI:43.6%-77.8%).

CONCLUSIONS

In the setting of a FOBT-based screening programme for CRC, CTC showed a high sensitivity, but relatively low specificity and positive predictive value, for cancer and adenoma ≥6 mm. Probably performing CTC without faecal tagging as second line test after a positive FOBT is not a cost-effective strategy.

The effect of activity outside the field of view on image quality for a 3D LSO-based whole body PET/CT scanner

The purpose of this study was to quantify the influence of outside field of view (FOV) activity concentration (A(c)(,out)) on the noise equivalent count rate (NECR), scatter fraction (SF) and image quality of a 3D LSO whole-body PET/CT scanner. The contrast-to-noise ratio (CNR) was the figure of merit used to characterize the image quality of PET scans. A modified International Electrotechnical Commission (IEC) phantom was used to obtain SF and counting rates similar to those found in average patients. A scatter phantom was positioned at the end of the modified IEC phantom to simulate an activity that extends beyond the scanner. The modified IEC phantom was filled with (18)F (11 kBq mL(-1)) and the spherical targets, with internal diameter (ID) ranging from 10 to 37 mm, had a target-to-background ratio of 10. PET images were acquired with background activity concentrations into the FOV (A(c)(,bkg)) about 11, 9.2, 6.6, 5.2 and 3.5 kBq mL(-1). The emission scan duration (ESD) was set to 1, 2, 3 and 4 min. The tube inside the scatter phantom was filled with activities to provide A(c)(,out) in the whole scatter phantom of zero, half, unity, twofold and fourfold the one of the modified IEC phantom. Plots of CNR versus the various parameters are provided. Multiple linear regression was employed to study the effects of A(c)(,out) on CNR, adjusted for the presence of variables (sphere ID, A(c)(,bkg) and ESD) related to CNR. The presence of outside FOV activity at the same concentration as the one inside the FOV reduces peak NECR of 30%. The increase in SF is marginal (1.2%). CNR diminishes significantly with increasing outside FOV activity, in the range explored. ESD and A(c)(,out) have a similar weight in accounting for CNR variance. Thus, an experimental law that adjusts the scan duration to the outside FOV activity can be devised. Recovery of CNR loss due to an elevated A(c)(,out) activity seems feasible by modulating the ESD in individual bed positions according to A(c)(,out).

Value of endorectal MRI and MRS in patients with elevated prostate-specific antigen levels and previous negative biopsies to localize peripheral zone tumours

AIM

To evaluate prospectively the role of endorectal magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) in detecting peripheral zone tumour in patients with total prostate-specific antigen (PSA) values>or=4 ng/ml and one or more negative transrectal ultrasound (TRUS) biopsy rounds.

MATERIAL AND METHODS

Fifty-four consecutive men (mean age 65.4+/-5.2 years, mean total PSA 10.8+/-7.5 ng/ml), underwent a combined MRI-MRS examination with endorectal coil. MRI included transverse, coronal, and sagittal T2-weighted and transverse T1-weighted fast spin-echo sequences. MRS data were acquired using a double spin-echo point resolved spectroscopy (PRESS) sequence. A 10-site scheme was adopted to evaluate the prostate peripheral zone. A peripheral prostatic site was classified as suspicious if low intensity signal was present on T2-weighted images and/or if the choline+creatine/citrate ratio was >0.86. Following MRI-MRS all patients were submitted to a standard 10-core biopsy scheme to which from one to three supplementary samples were added from suspicious MRI and/or MRS sites. In per-patient analysis findings were considered true-positive if biopsy positive patients were classified as suspicious, irrespectively of lesion site indication.

RESULTS

Prostate cancer (PC) was detected in 17 of 54 patients (31.5%); median Gleason score was 6 (range 4-8). On a per-patient basis sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were respectively 100, 64.9, 56.7, 100, and 75.9% for MRI; 82.2, 70.3, 57.7, 92.9, and 75.9% for MRS; and 100, 51.4, 48.6, 100, and 66.7% for combined MRI-MRS. In all the 17 PC patients, combined MRI-MRS correctly indicated the sites harbouring cancer, whereas both MRI and MRS gave erroneous indications in two patients.

CONCLUSION

The results of the present study show that MRI alone might be able to select negative patients in whom further biopsies are unnecessary. The combination of MRI and MRS might be able to drive biopsies in suspicious sites and increase the cancer detection rate. Further studies are required to confirm these data.

Multiple sampling 13C-urea breath test: improvement of diagnosis in postgastrectomy patients

AIM

Partial gastrectomy and Helicobacter pylori (H. pylori) infection are considered 2 risk factors for gastric cancer development. False negative urea breath test (UBT) results have been described in patients with gastric surgery, due to rapid gastric emptying of urea solution from the stomach. On the other hand, a rapid 10-minute 14C-UBT proved to be highly reliable for diagnosis of H. pylori infection when delaying test meal was omitted. Aim of this study was to improve the diagnostic accuracy of 13C-UBT in patients with gastric resection.

METHODS

UBT was performed in 100 gastrectomised patients with breath collection at 0, 10, 15, 20, 25 and 30 minutes (multi-UBT) after 100 mg 13C urea ingestion and 100 ml of marketed fruit juice. In 28 cases contemporary histological data from biopsy specimens (within 1 month, in absence of treatment) were also available.

RESULTS

Multi-UBT was persistently negative or positive in all the samplings in 34% and 25% of cases, respectively. Positivity only at 30 minutes was found in 10% of cases, while 19% of subjects were positive at 15-25 minutes but not at 30 minutes. In 12% of cases the test was positive only at 10 minutes.

CONCLUSIONS

Multi-UBT offers a not negligible diagnostic improvement over the standard UBT: at least 19%, and up to 31% if positivity at ''10-minute only'' is taken into account. This method can be useful when accurate diagnosis of H. pylori infection is required in gastrectomised patients.

Alcohol abstinence does not offset the strong negative effect of lifetime alcohol consumption on the outcome of interferon therapy

Heavy alcohol consumption has been reported to negatively affect the outcome of interferon therapy. We studied the impact of lifetime alcohol consumption in patients with chronic hepatitis C treated with interferon after 6 months of alcohol withdrawal. Alcohol intake was measured when patients with chronic hepatitis C were referred to us for the first time, and from that moment complete abstinence was recommended. After 6 months of abstinence, 150 patients with persistent elevated serum alanine aminotransferase (ALT) have been treated with interferon (IFN)-alpha, 3 or 6 microU three times per week for 12 months. Univariate and multivariate analysis were performed to identify the predictors of treatment response. Carbohydrate-deficient transferrin was employed to assess alcoholic abstinence. The sustained response rate felt from 33% in nondrinkers to 20% of mild-drinkers and to only 9% in heavy drinkers. Drinker patients showed a relapse rate twice as high as that of nondrinkers. According to the multivariate analysis, the strongest independent predictors of nonresponse were genotype 1b infection, age of the patients and their lifetime alcohol intake. Carbohydrate-deficient transferrin detected at baseline, at 3 months of therapy and at the end of follow-up gave a positive result only in eight determinations (1.77%), confirming the compliance of patients to our recommendation of alcohol abstinence. Lifetime alcohol consumption has a strong negative effect on the outcome of interferon treatment, mainly in heavy drinkers. A 6-month period of abstinence may not be sufficient to offset this negative effect on treatment outcome.

Effectiveness of Helicobacter pylori eradication treatments in a primary care setting in Italy

AIM

To evaluate the choice and relative effectiveness of Helicobacter pylori eradication regimens in a primary care setting.

PATIENTS AND METHODS

Patients referred to our department, who had been treated for H. pylori infection during the preceding 6 months, were enrolled between September 1998 and July 1999. H. pylori status was assessed by urea breath test. Information on the drugs administered, compliance and side-effects was recorded.

RESULTS

The mean eradication rate was 72% in patients receiving their first course of treatment (1863 cases; 45% male; mean age, 53 +/- 14 years); a double therapy regimen was prescribed to 14% of patients, triple therapy to 85% and quadruple therapy to 1%. Maastricht Consensus proton pump inhibitor-based regimens were prescribed in 80% of cases, with a mean eradication rate of 73%. No statistically significant correlation was found between eradication failure and sex, age, endoscopic findings or administered treatment.

CONCLUSIONS

In Italy, in a primary care setting, first-line H. pylori eradication therapies reflect international guidelines. The efficacy of such regimens is lower than that reported by controlled trials. These results are relevant when making pharmacoeconomic evaluations of H. pylori management.

Modality of treatment and outcome of Helicobacter pylori infection in primary care. An Italian experience

BACKGROUND

Aim of the present study was to evaluate the selection and the relative efficacy of H. pylori eradication regimens in primary care setting.

METHODS

Patients referred to our Department, treated for H. pylori infection during the last 6 months, were enrolled during September 1998-July 1999. H. pylori status was assessed by urea breath test and recorded together with information about administered drugs, compliance, side effects.

RESULTS

In patients undergone the first treatment course (1863 cases, 45% M, mean age 53+/-14 yrs) the mean eradication rate (ER) was 72%: a double therapy was prescribed in 14% of cases, a triple therapy in 85% and a quadruple in 1%. Maastricht Consensus PPI-based regimens were prescribed in 80% of total cases with a mean ER of 73%. No statistical significant correlation was found between eradication failure and sex, age or administered treatment.

CONCLUSIONS

In Italy, in primary care setting: 1) first line H. pylori eradication therapies reflect international guidelines; 2) the efficacy of such regimens is lower than the one reported by controlled trials: such data should be kept in mind when pharmacoeconomic evaluations of H. pylori management are drawn.

Impact of urea breath test (UBT) in the management of H. pylori infection in a primary care setting

BACKGROUND

Aim of the present study was to evaluate the use of UBT in a primary care setting.

METHODS

From September 1998 to July 1999 we studied 2810 consecutive patients, referred to the Department of Gastroenterology, Mauriziano Hospital, Torino. A structured questionnaire was used to record information on demographic characteristics and clinical history. 13C-UBT was performed by means of isotope ratio mass spectrometer.

RESULTS

The results shown that: 1) the main indication to perform UBT was the evaluation of treatment success (72% of cases); 2) in patients aged less than 45 years and never assessed before for H. pylori infection, UBT was used as first line procedure in 68% of cases: this finding stand for an initial adoption of the ''test and treat'' strategy; 3) first line H. pylori eradication therapies reflect international guidelines.

CONCLUSIONS

The effectiveness of therapeutic regimens results to be decreased when translated into routine clinical practice.

Interferon and amantadine in combination as initial treatment for chronic hepatitis C patients

BACKGROUND/AIMS

To evaluate the efficacy and tolerance of amantadine in combination with interferon in the treatment of chronic hepatitis C.

METHODS

Multi-centre trial including 180 chronic hepatitis C patients without cirrhosis, randomly enrolled to receive interferon 6 MU every other day for 6 months followed by 3 MU for further 6 months (group A, 90 patients), or the same schedule plus amantadine 200 mg/day (group B, 90 patients). Primary end-point was a sustained virological and biochemical response, secondary end-points were on-treatment (third month) and end-of-treatment response rates.

RESULTS

The two groups had similar demographic, biochemical and virological characteristics. A sustained response after 6 months follow-up was observed in 17% of group A and 24% of group B patients (P not significant), an end-of-treatment response was observed in 37% in group A and 47% in group B (P not significant), an on-treatment response was observed in 46% in group A and 61% in group B patients (P < 0.05). No major side effects due to amantadine administration were observed.

CONCLUSIONS

Adding amantadine to interferon did not improve the sustained treatment efficacy. However, the rate of early response at the third month of therapy was significantly higher in the combination therapy group.

Fecal pancreatic elastase 1 in the work up of patients with chronic diarrhea

BACKGROUND

Quantitative determination of pancreatic elastase-1 (E1) in stools has been proposed as a novel, noninvasive test of pancreatic function. The aim of the study was to verify its role in the differential diagnosis of chronic diarrhea.

METHODS

E1 was measured in spot stool samples of 50 patients with pancreatic disease (PD), 62 with inflammatory bowel disease (IBD), 45 with chronic diarrhea (CD), 34 with other gastroduodenal and liver disease (gastrointestinal; GI), and in 18 normal controls, by a commercial kit (Schebo-Tech., Wettemburg, Germany).

RESULTS

In PD, patients with severe damage and diarrhea displayed E1 levels below 100 microg/g; normal values were found in mild-moderate disease. Abnormal values were detected in 4 CD and in 14 IBD patients, either in the presence of severe protein malnutrition or in patients with previous ileo-anal pouch anastomosis and pouchitis. In nine cases, values reverted to normal after adequate treatment. Diagnostic accuracy of E1 in discriminating diarrhea of pancreatic and nonpancreatic origin was: SS, 97%; SP, 84%; VP+, 66%; VP-, 100%.

CONCLUSION

1) The finding of a normal E1 value rules out a malabsorption of pancreatic origin. 2) in CD and IBD, decreased E1 might be owing to bacterial elastase degradation (pouchitis) or transient defective pancreatic enzyme secretion.

Helicobacter pylori infection in type 2 diabetic patients

BACKGROUND AND AIM

A high prevalence of Helicobacter pylori (Hp) infection in diabetic patients has been described in recent years. This study investigates its prevalence in type 2 diabetics and its correlation with the degree of metabolic control and the presence of chronic complications.

METHODS AND RESULTS

Forty-one consecutive type 2 diabetics (21 males, 20 females aged 46-78, mean 62) and 31 age-matched controls participated. Hp infection was assessed by means of the 13C-urea breath test. Fasting glucose and glycated haemoglobin (HbA1c) levels were measured to evaluate metabolic control. Chronic complications were assessed by means of albumin excretion rate (AER), fundoscopy, vibratory perception threshold (VPT), ECG, clinical history of coronary, cerebral or peripheral arteriopathy, foot examination and cardiovascular autonomic function tests. A higher prevalence of Hp infection was found in diabetic than in control women (80% vs 37.5%; p < 0.05), whereas there was no difference between males. A higher prevalence correlated with macroangiopathy and neuropathy and higher BMI, blood pressure, fasting glucose and HbA1c values. By contrast, microangiopathy was significantly more prevalent (p < 0.05) in Hp negative (85%) than in Hp positive patients (48%).

CONCLUSIONS

There is a high prevalence of Hp infection in type 2 diabetic women. The absence of microangiopathy may be a predisposing factor: microvascular changes in the gastric mucosa may create an unfavourable environment for the establishment or survival of Hp.

Discrepancy between Helicobacter pylori stool antigen assay and urea breath test in the detection of Helicobacter pylori infection

BACKGROUND

The reference diagnostic methods available for detection of Helicobacter pylori infection are either invasive (histology) or expensive and highly sophisticated (Urea Breath Test). A new enzyme immunoassay, which can be easily performed in any laboratory, has been developed to detect Helicobacter pylori in stool specimens (HpSA-Meridian Diagnostics, Cincinnati, USA). Aim of the study was to compare HpSA to Urea Breath Test.

PATIENTS AND METHODS

A total of 125 patients (52 never treated for Helicobacter pylori infection and 73 after Helicobacter pylori eradication therapy) referring to our Department, underwent both tests within two weeks.

RESULTS

Contrasting results between the two tests were found in 30% of cases: in 19% of the untreated patients and in 37% of the treated patients (p<0.001). The main discrepancy consisted in positive HpSA associated with negative Urea Breath Test. Mean HpSA value in such conditions was 0.273 optical density, while in patients with both positive tests, it was 1.192 optical density. In untreated, but not in treated patients, raising the HpSA cut off value significantly decreased the percentage of conflicting results.

CONCLUSIONS

Some disagreement was detected between HpSA and Urea Breath Test results, especially in treated patients. Possible explanations for our findings are a low HpSA cut off value together with the identification of Helicobacter pylori coccoid forms by the immunoassay but not by the urease based Urea Breath Test. The higher percentage of discrepancy detected in treated patients might support this hypothesis.