Percutaneous abscess drainage using near real-time MR guidance in an open 1.0-T MR scanner: proof of concept.

OBJECTIVES: The aims of our study were (1) to assess the feasibility, effectiveness, and safety of exclusively magnetic resonance (MR)-guided freehand percutaneous abscesses drainage using a 1.0-T open MR scanner and (2) to evaluate the optimal method to visualize drainage catheters in situ. MATERIAL AND METHODS: In vitro studies in a dedicated MR gelatin phantom were performed to assess visualization of 8 different sizes of drainage catheters after instillation of sole 0.9% sodium chloride (NaCl) and diluted (1.0%) or concentrated (12.0%) gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) using a T1-weighted (T1w) 2-dimensional fast field echo (FFE) and a T2-weighted single-shot (ssh) turbo spin-echo (TSE) fast dynamic sequence. The catheter artifacts were evaluated with regard to the contrast-to-noise ratio (CNR), the artifact width using the full width at half-maximum (FWHM) method, and the artifact intensity, being the product of the CNR and the FWHM. We used the general linear model procedure as the global test and the Tukey studentized range test for post hoc analysis. In vivo MR-guided freehand drainage was prospectively performed in patients with increased systemic inflammation markers and abdominal, retroperitoneal, and pelvic abscess collections. This study had been approved by the institutional review board. All patients provided written informed consent. Technical success was the primary efficacy variable. The secondary efficacy variables were visibility of the puncture needle and drainage catheter artifact, using a qualitative 5-point rating scale, intervention and procedure time, and rate of postinterventional complications. RESULTS: The FWHM, the CNR, and the artifact intensity of the drainage catheters filled with 0.9% NaCl or diluted or concentrated Gd-DTPA increased according to the drainage catheter size in an almost linear fashion in both image weighting (all P ≤ 0.006; all R(2) ≥ 0.73). The T1w FFE sequence yielded the highest FWHM, CNR, and artifact intensity of all groups, using 12.0% Gd-DTPA instillation (all P < 0.001), and the least FWHM and artifact intensity, using 1.0% Gd-DTPA instillation (all P < 0.022; all P < 0.009). The T2w ssh TSE yielded higher FWHM, using 12.0% Gd-DTPA instillation, whereas the CNR was higher for 0.9% NaCl instillation (all P < 0.001). Magnetic-resonance-guided abscess drainage was performed in 22 patients with 24 abdominal, retroperitoneal, or pelvic abscess collections. The technical success rate of in vivo MR-guided freehand drainage was 100%. Visibility of the puncture needle was excellent (≥4.4 [0.5] points). Visibility of the drainage catheters was rated with 3.9 (0.9) and 4.5 (0.8) points using T2w ssh TSE with 0.9% NaCl and 12.0% Gd-DTPA instillation as well as 4.8 (0.5) and 4.2 (0.8) points using T1w FFE with 1.0% and 12.0% Gd-DTPA instillation, respectively. The procedure and intervention time was 52.4 (16.4) minutes (range, 28-78 minutes) and 27.4 (7.2) minutes (range, 17-40 minutes). Two minor and no major complications were recorded. CONCLUSIONS: Magnetic-resonance-guided freehand percutaneous abscesses drainage using fast dynamic sequences in an open 1-T MR scanner is feasible, effective, and safe. Visualization of drainage catheters can be facilitated by instillation of 0.9% NaCl or diluted or concentrated contrast media.

Identification of clinical and laboratory markers for predicting eosinophilic esophagitis in adults.

BACKGROUND: The diagnosis of eosinophilic esophagitis (EoE) and differentiation from gastroesophageal reflux disease (GERD) is potentially challenging and is based upon clinical signs and endoscopic and histological features. In order to alert the endoscopist to consider EoE in patients with esophageal symptoms before performing esophagogastroduodenoscopy, we aimed to identify a set of clinical and laboratory markers for predicting EoE. METHODS: The study included 43 patients with either EoE (n = 23) or GERD (n = 20). The diagnosis of EoE was based on International Consensus Criteria. Age, gender, weight loss, history of atopy, dysphagia, history of food impaction, proton pump inhibitor (PPI) refractory heartburn, odynophagia, peripheral eosinophilia, and serum IgE were analyzed. Each symptom or sign was classified as '0' (absent, normal) or '1' (present, elevated), individually analyzed and statistically evaluated among the two groups of patients. Logistic regression analysis was carried out to identify a clinically applicable marker constellation to differentiate EoE from GERD. RESULTS: Univariate analysis identified 6 out of the 10 variables to be significant between both groups. A stepwise procedure of logistic regression led to a model in which 3 out of the initial 10 items were found to be relevant for differentiating GERD and EoE. Derived from this model, an optimal differentiation was achieved by using the following simplified equation: peripheral eosinophilia + history of food impaction + PPI refractory heartburn leading to a maximal value of 3 (1 + 1 + 1). Based on a cut-off value of ≥2, sensitivity and specificity for diagnosing EoE were 91 and 100%, respectively. CONCLUSION: A defined set of markers including two clinical features and one laboratory parameter is highly predictive of EoE and thus allows physicians to distinguish EoE from GERD even before upper gastrointestinal endoscopy is performed.

Gene polymorphisms of folate metabolizing enzymes and the risk of gastric cancer.

Multiple studies have reported an association between disturbances of folate metabolism and increased risk of gastric cancer, including low intake of folate, low levels of folate in blood or genetic factors affecting folate metabolism. Among the genetic factors, in particular a common polymorphism in the gene encoding for 5,10-methylenetetrahydrofolate reductase (MTHFR C677T) has been linked to gastric cancer. Other polymorphisms in folate-metabolising genes have been less frequently investigated. Therefore, we analyzed this polymorphism, the glutamate carboxypeptidase (GCP) II C1561T and the reduced folate carrier (RFC) G80A in a case-control study involving 106 patients with histologically confirmed and characterized gastric cancer with adjustment for other established risk factors for gastric cancer in comparison to 106 age- and sex-matched controls. Neither the MTHFR nor the GCP gene polymorphisms showed an association to cancer diagnosis, to tumor stage, grade of differentiation or Lauren type. However, non-cardia cancers were more likely to exhibit the 80GA and 80AA RFC genotypes, compared to cancers of the gastric cardia (adjusted OR 0.28; 95% CI=0.11-0.71). Thus, gene polymorphisms of the RFC gene might contribute to an increased risk of developing distal gastric cancer.

Diagnostic performance of a flat-panel detector at low tube voltage in chest radiography: a phantom study.

RATIONALE AND OBJECTIVES: To evaluate a large area, cesium iodide amorphous silicon flat-panel detector (CsI/a-Si) at 3 tube voltages to detect simulated interstitial lung disease, nodules, and catheters. METHODS: Simulated interstitial lung disease, nodules, and catheters were superimposed over a chest phantom. Images were generated at 125 kVp, 90 kVp, and 70 kVp at the same surface dose and reduced effective dose equivalent for 90 kVp and 70 kVp and printed on hard copies. Fifty-four thousand observations were analyzed by receiver operating characteristic (ROC). RESULTS: Detectability of linear, miliary, reticular pattern, and nodules over lucent lung as well as of catheters and nodules over obscured chest areas increased at 90 and/or 70 kVp with higher Az values; however, only it was statistically significant for reticular pattern at 70 kVp and nodules at 90 kVp compared with 125 kVp (P < 0.05). The detection of ground-glass pattern was worse at lower kVp (P > 0.05). CONCLUSION: For most simulated patterns, differences in diagnostic performance at 70 kVp/90 kVp and 125 kVp were not significant, except for reticular pattern and nodules over lucent lung.