Double-contrast Technique Research Articles

Interfacial Distribution of Nafion Ionomer Thin Films on Nitrogen-Modified Carbon Surfaces.

Chemically modified carbon supports for the cathode catalyst layers of polymer electrolyte fuel cells (PEFCs) show considerable promise for boosting the oxygen reduction reaction. This study evaluated the ionomer distribution of Nafion ionomer thin films on nitrogen (N)-modified carbon surfaces along their depth direction. Neutron reflectivity (NR) measurements performed using the double-contrast technique with H2O and D2O revealed that the introduction of N functional groups to carbon thin films promoted ionomer adsorption onto the surface under wet conditions (22 °C, 85% relative humidity). Molecular dynamics (MD) simulations conducted to verify the origin of the robust contact between the ionomer and N-modified carbon surface revealed an ionomer adsorption mechanism on the N-modified carbon surfaces, which involved Coulomb interactions between the positively charged carbon surface and the ionomer side chains with negatively charged sulfonic acid groups. The positive surface charge, which was determined using the contents of the N functional groups estimated by X-ray photoelectron spectroscopy, was found to be sufficient as an impetus for ionomer adsorption. This strategy involving NR measurements and MD simulations can provide insights into the solid-ionomer interfacial structures in a cathode catalyst layer and can therefore be extensively employed in studies on PEFCs.

Comparison of radiographic methods for detecting radiolucent uroliths in dogs.

The purpose of this study was to evaluate and compare positive cystography techniques at 5%, 10%, and 20%, as well as three different double-contrast protocols for detecting radiolucent uroliths with a diameter of less than 3.0 mm in dogs. Six cadavers were used, one was selected at random to represent the negative control, and the others were submitted to urolith implantation in the bladder by urethral catheter. Three radiology professionals blindly accessed ventrodorsal and -lateral projections of each test. Contrast at 20% showed greater diagnostic sensitivity, but with greater difficulty identifying the number and size of the uroliths. Consequently, double-contrast techniques are better and should be used for diagnostic and therapeutic planning. Sensitivity and specificity tests demonstrated that positive 5% cystography and different concentrations of double contrast obtained better results in terms of sensitivity and specificity. However, due to the presence of a greater amount of artifacts in the 5% cystography, it is suggested that double contrast is used for this purpose, especially with the removal of contrast excess (protocol 2).

Radiographic and tomographic description of marlin sucker Remora osteochir, Pisces: Echeneidae—preliminary data of one specimen

Remoras are commensal fish of various marine species, such as sharks, swordfishes, turtles, dolphins, manta rays and whales. One specimen of marlin sucker Remora osteochir was evaluated using computed tomography for skeletal digital reconstruction, digital radiology for general evaluation and bone counting, and the double contrast technique to distinguish coelomic organs. In radiographic images, it was possible to observe otoliths in the center of the neurocranium, to count 27 vertebrae, nine pairs of ribs, and to detect the presence of the hipural and epural bones near of the caudal fin. In double contrast images, it was possible to visualize the swim bladder, gills, heart, liver, stomach and intestines. From the tomographic images and reconstructions, it was possible to identify the intercalar bones of the cephalic disc; the spine with vertebral bodies composed of neural arches and ventral ribs; and the pectoral girdle formed by posttemporal, cleithrum and scapulocoracoid bones. It was concluded that digital radiology and computed tomography were able to describe anatomical structures of marlin sucker R. osteochir without the need for dissection.

Double-contrast tongue surface imaging technique in swallowing computed tomography

Double-contrast tongue surface imaging technique in swallowing computed tomography

Inflammatory diseases of the upper gastrointestinal tract : Role of radiology in diagnostics

The radiological evaluation of the upper gastrointestinal tract (GI tract) is adiagnostic challenge. Although endoscopy has pushed radiographic methods into the background, these methods continue to play akey role in the diagnosis of dysphagia. In addition, cross-sectional imaging (computed tomography, magnetic resonance imaging) is increasingly used in complex clinical cases to evaluate surrounding tissue changes. By combining conventional double-contrast techniques with avideo recording, the entire upper GI tract can be assessed both anatomically and functionally in one examination procedure. In addition to the clarification of swallowing disorders, videofluoroscopy can be used to assess postoperative control after antireflux and bariatric surgery. To obtain optimal results in video swallowing studies, the procedure should be adapted to the individual symptoms of the patient.

Appearance of Krukenberg tumor from gastric carcinoma, ultrasound and computed tomography evaluation

The Krukenberg tumor is a rare malignant tumor of the ovary, accounting from 1% to 2% of all ovarian tumors. It is usually a bilateral involvement of ovaries from the metastatic deposit from adenocarcinoma of the stomach. We present a patient at the age of 45, who visited a doctor because of pain in the stomach, nausea, and vomiting and weight loss of more than 20 kg. Clinical, biochemical, endoscopic, pathohistological, radiological and imaging studies [ultrasound (US) and computed tomography (CT)] have been performed. The radiological examination was performed using a noncontract and double-contrast technique. The US examination was performed with a 3.75 MHz convex probe, using a standard overview technique. CT was made after oral administration of 700 mL of water, i.v. application of a non-ionic contrast agent of 90 mL in bolus, in hypotonia achieved by i.v. glucagon application, with a scanning width of 10 mm. The radiological finding is in favor of diffuse neoplastic submucosal infiltration of the stomach wall in the region of the corpus and antrum with expressed desmoplastic reaction (linitis plastica). CT findings confirm the radiological findings of the stomach, clearly visualize metastases in the ovaries and peritoneum-ascites, thus diagnosing the primary inoperable neoplastic stomach process—linitis plastica, with metastases in the ovaries—Krukenberg tumor. A comparison of the obtained radiological and imaging results with the endoscopic and pathohistological findings has been made. Krukenberg tumor is an ovarian metastasis of digestive tract cancer. Radiological and especially imaging methods have high diagnostic value and accuracy.

Diagnostic Potentialities of Multispiral Computed Tomography for Hip Joint Evaluation in Children and Adolescents

Multispiral computed tomography (MSCT) is a method of choice for evaluation of bone structure condition, as well as for visualization of growth zones, main and additional ossific nuclea of the articular elements. Besides, MSCT provides precise evaluation of spatial orientation of hip joint components, pattern of bone fragments displacement in traumatic injuries, localization of pathologic focus in bone pathology and degree of adjacent anatomic structures involvement. Contrast enhancement (double-contrast technique) markedly widens potentialities of this method as it enables to evaluate the condition of articular cartilage and soft tissue structures that is the most actual in young children.

Colonic stent placement: a “double contrast technique”: slightly novel approach

Colonic stent placement: a “double contrast technique”: slightly novel approach

Enteroclysis: Current clinical value

To retrospectively analyze changes in clinical indication, referring medical specialty and detected pathology for small bowel double-contrast examinations. Two hundred and forty-one (n = 143 females; n = 98 males; 01.01.1990-31.12.1990) and 384 (n = 225 females; n = 159 males; 01.01.2004-31.12.2010) patients underwent enteroclysis, respectively. All examinations were performed in standardized double-contrast technique. After placement of a nasojejunal probe distal to the ligament of Treitz, radiopaque contrast media followed by X-ray negative distending contrast media were administered. Following this standardized projections in all four abdominal quadrants were acquired. Depending on the detected pathology further documentation was carried out by focused imaging. Examination protocols were reviewed and compared concerning requesting unit, indication and final report. Two hundred and forty-one examinations in 1990 faced an average of 55 examinations per year from 2004-2010. There was an increase of examinations for gastroenterological (33.6% to 64.6%) and pediatric (0.4% to 7.8%) indications while internal (29.0% to 6.0% for inpatients and from 16.6% to 9.1% for outpatients) and surgical (12.4% to 7.3%) referrals significantly decreased. "Follow-up of Crohn's disease" (33.1%) and "bleeding/tumor search" (15.1%) represented the most frequent clinical indications. A total of 34% (1990) and 53.4% (2004-2010) examinations yielded pathologic findings. In the period 01.01.2004 -31.12.2010 the largest proportion of pathological findings was found in patients with diagnosed Crohn's disease (73.5%), followed by patients with abdominal pain (67.6% with history of surgery and 52.6% without history of surgery), chronic diarrhea (41.7%), suspected Crohn's disease (39.5%) and search for gastrointestinal bleeding source/tumor (19.1%). The most common pathologies diagnosed by enteroclysis were "changes in Crohn's disease" (25.0%) and "adhesions /strictures" (12.2%). "Crohn's disease" represents the main indication for enteroclysis. The relative increase of pathologic findings reflects today's well directed use of enteroclysis.

X-ray Diagnosis of Early Gastric Cancer

The authors introduced the present state of diagnosis and treatment of gastric in Japan. Japanese classification of gastric cancer is also introduced. Several X-ray pictures of 7 cases of early gastric with their macroscopical and microscopical findings according to the order of this classification are presented. The role and superiority of double contrast technique in detecting and making diagnosis of early gastric are discussed. The possibility of marked shrinkage of benign ulcer exsisting inside the early gastric lesion is presented, and the importance of following up the course of all the benign ulcer cases for making preoperative X-ray diagnosis is emphasized. The key point to diagnosis of flat type early gastric (IIb type) is also described.

Valoración de los signos radiológicos más frecuentes relacionados con el cáncer colorrectal, obtenidos mediante la técnica de doble contraste

Objectives To determine the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the main radiologic signs on the double-contrast technique in the diagnosis of colorectal cancer. Material and methods We retrospectively analyzed axial slices and clinical histories of 132 patients of whom 18 (13.64%) were diagnosed with colorectal cancer. Results The mean age of the patients with colorectal cancer was 61 years; 11 (61.11%) were male and 7 (38.89%) were female. According to Dukes’ classification, 1 (5.55%) patient had stage A disease, 3 (16.66%) stage B, 8 (44.44%) stage C, and 6 (33.33%) stage D. We detected polyps in 100% of the images obtained by subtraction and diverticula in 100% of those obtained by addition. The distribution by colon segments was as follows: ascending colon n=2 (11.11%), transverse colon n=4 (22.22%), descending colon n=2 (22.22%), sigma n=6 (33.33%), and rectum n=4 (22. 22%). The diagnostic accuracy of the technique was sensitivity 83.33%, specificity 99.25%, PPV 88.24%, and NPV 97.39%. Conclusions Colorectal cancer is more common in people older than 50 years. Polyps on subtraction and diverticula on addition are the most common radiologic signs in colorectal cancer when the double-contrast technique is used. The principal radiologic signs on the double-contrast technique are highly sensitive and highly specific for the diagnosis of colorectal cancer.

Double-contrast magnetic resonance imaging of hepatocellular carcinoma after transarterial chemoembolization

The purpose of this study was to assess the accuracy of double-contrast magnetic resonance (MR) imaging for the treatment response evaluation of hepatocellular carcinoma (HCC) in cirrhotic liver after transarterial chemoembolization (TACE). Twenty-two patients with 30 HCC nodules treated by TACE underwent double-contrast MR imaging 1 month after treatment. MR images were obtained before and after the sequential administration of superparamagnetic iron oxide (SPIO) and gadopentetate dimeglumine contrast agent within the same imaging session. Two observers retrospectively assessed all treated nodules for evidence of residual viable tumor after TACE. The diagnostic performance of gadolinium-enhanced, SPIO-enhanced, and double-contrast enhanced images was calculated. Histopathological and angiographical findings served as standard of reference. Receiver operating characteristic curves and areas under the curves (A (z)) were calculated. Double-contrast technique (A (z) = 0.95) was significantly (p = 0.036) more accurate than SPIO-enhanced technique (A (z) = 0.92) and gadolinium-enhanced technique (p = 0.005) (A (z) = 0.81) in viable tumor detection after TACE. Double-contrast technique was significantly more sensitive (92%) than SPIO-enhanced technique (80%) and gadolinium-enhanced technique (68%). Kappa values for interobserver agreement ranged from 0.67 to 0.87 and were significantly different from zero (all p < 0.001). Compared to gadolinium-enhanced and SPIO-enhanced techniques, double-contrast technique significantly improves the detection of viable tumor in HCC after TACE.

Double contrast barium enema: Technique, indications, results and limitations of a conventional imaging methodology in the MDCT virtual endoscopy era

The double contrast barium enema of the colon continues to be a diffused conventional radiological technique and allows for the diagnosis of neoplastic and inflammatory pathology. After the ’70s, a massive initiative is undertaken to simplify, perfect and encode the method of the double contrast barium enema: Altaras from Germany, Miller from USA and Cittadini from Italy are responsible for the perfection of this technique in the last 30 years. The tailored patient preparation, a perfect technique of execution and a precise radiological documentation are essentials steps to obtain a reliable examination. The main limit of double contrast enema is that it considers the pathology only from the mucosal surface. In neoplastic pathology evaluation the main limit is the “T” parameter staging, but more limited are the “N” and “M” parameters evaluation. Today the double contrast technique continues to be a refined, sensitive and specific diagnostic method, moreover, diagnostic results cannot compete with the new CT multislice techniques (CT-enteroclysis and virtual colonoscopy) which can examine both the lumen and the wall of the colon. The double contrast is a cheap and simple examination but in the next future is predictably a progressive substitution of conventional radiology from new multislice techniques, because the cross sectional imaging is more frequently able to detect causes of the symptoms whether resulting both from colonic or non colonic origin.

Double-Contrast Barium Enema: Use in Practice and Implications for CT Colonography

This study examines the use and yield of double-contrast barium enemas (DCBEs) for colorectal polyp detection in current clinical practice outside the research setting. My colleagues and I retrospectively reviewed adult DCBE studies performed in routine clinical practice at a single academic institution from 2001 through 2004 by reviewing the official radiology and colonoscopy reports. Data were collected on indications for a DCBE, number of positive and negative DCBE reports, results of a DCBE after failed colonoscopy, and professional profiles of the radiologists who performed the DCBEs. Correlation for colon polyp detection was made by reviewing reports of colonoscopy performed within 12 months before or after a DCBE. Polyp detection and matching analysis used a six-segment colon localization scheme. A total of 244 out of 665 (36.7%) barium enema studies were performed using the double-contrast technique over the 4-year period-that is, approximately one per week. The most common indication for a DCBE (109/244 or 44.6%) was to complete a failed, incomplete, or inconclusive colonoscopy. Overall, only 14 of the 244 (5.7%) studies gave positive reports for polyps, and of these, five were shown to be false-positive at later colonoscopy. Only six polyps 10 mm or larger were positively detected during the entire study, which is approximately one per 60 studies or one every 8 months. In 104 patients who had negative DCBEs after failed or inconclusive colonoscopy, more than 50 subcentimeter polyps had been detected and removed, yet not one additional polyp was detected by a DCBE. Of the 15 radiologists performing the DCBEs during the study period, 89.7% of the studies were done by four individuals. Three of these four radiologists were older than 60 years at the beginning of the study, and two of them are now either retired or no longer perform fluoroscopy. In our center, a DCBE is a low-yield procedure for detecting polyps, with a high false-positive rate, and is not likely to be performed by experienced practitioners in the future.

Anatomie et imagerie du duodénum

The duodenum is the first part of the small bowel. It extends from the pylore to the duodeno-jejunal flexure. The duodenum is divided into four parts. Endoscopy is usually the first-line imaging technique used in case of suspected duodenal abnormalities. Barium examination with double contrast technique has a good sensitivity for detailed evaluation of mucosal lesions and bowel wall. Ultrasonography and computed tomography may sometimes detect duodenal lesions previously unsuspected. Magnetic resonance imaging may also appreciate the duodenum. As the duodenum is located around the pancreatic head, cross section imaging is frequently used to evaluate simultaneously these two structures.

A Novel Double-Contrast Technique to Facilitate MRI-Guided Vascular Interventions: Combined Use of a Blood-Pool Agent and Carbon Dioxide

A Novel Double-Contrast Technique to Facilitate MRI-Guided Vascular Interventions: Combined Use of a Blood-Pool Agent and Carbon Dioxide

A Prospective Comparison of Capsule Endoscopy, Enteroclysis and Enteroscopy in Peutz-Jeghers Syndrome

Background: Peutz-Jeghers syndrome (PJS) is characterized by the presence of hamartomatous polyps throughout the gastrointestinal tract, most frequently in the small intestine. Management centres on the prevention of gastrointestinal complications arising from small bowel polyposis. Small bowel radiography is recommended to reduce the risk of complications. Capsule endoscopy is a promising technique for endoscopic surveillance of small bowel polyposis. Aims: To compare polyp detection rates in patients with known PJS, using capsule endoscopy (CE), small bowel enteroclysis (SBE) and push enteroscopy (PE). Methods: 14 patients with established PJS were enrolled prospectively and 11 (4M7F) have completed evaluation (mean age/range M27.2/17-39, F30.6/17-57). After initial clinical evaluation to confirm the diagnosis, patients were evaluated by blinded investigators. All patients underwent SBE and CE before proceeding to PE when possible. SBE was performed by an expert gastrointestinal radiologist, using naso-jejunal intubation and double contrast technique (barium, methylcellulose and water). PE was performed by an experienced endoscopist using an Olympus SIF140 250 cm enteroscope. Polyps were deemed to be clinically significant when ≥1 cm (as measured at fluoroscopy, or at PE using an open biopsy forcep technique, or when occupying the majority of the lumen on CE). Patients were referred for surgery where clinically appropriate. Results: 3 patients (27%) did not tolerate nasojejunal intubation for SBE, and the procedure was performed as a barium meal with follow through. The difference between the mean number of polyps detected by SBE (0.54, range 0-1) and CE (2.63, range 0-10) approached statistical significance (p = 0.06). PE was undertaken in 8 patients (4M4F) and the mean number of polyps found was 2.42. Conclusions: These data suggest that capsule endoscopy should be the first-line investigation of the small bowel in PJS, rather than small bowel enteroclysis. In comparison with CE, SBE appears to have poor sensitivity in detecting clinically significant small bowel polyps. PE confirmed the presence of proximal polyps found on CE. CE may have underestimated the number of large polyps clustered in the proximal small bowel (as is common in PJS). CE did detect a number of distal polyps not identified on PE. Capsule endoscopy findings can be used to direct subsequent management (surgery or PE) depending on the location of the polyps. Background: Peutz-Jeghers syndrome (PJS) is characterized by the presence of hamartomatous polyps throughout the gastrointestinal tract, most frequently in the small intestine. Management centres on the prevention of gastrointestinal complications arising from small bowel polyposis. Small bowel radiography is recommended to reduce the risk of complications. Capsule endoscopy is a promising technique for endoscopic surveillance of small bowel polyposis. Aims: To compare polyp detection rates in patients with known PJS, using capsule endoscopy (CE), small bowel enteroclysis (SBE) and push enteroscopy (PE). Methods: 14 patients with established PJS were enrolled prospectively and 11 (4M7F) have completed evaluation (mean age/range M27.2/17-39, F30.6/17-57). After initial clinical evaluation to confirm the diagnosis, patients were evaluated by blinded investigators. All patients underwent SBE and CE before proceeding to PE when possible. SBE was performed by an expert gastrointestinal radiologist, using naso-jejunal intubation and double contrast technique (barium, methylcellulose and water). PE was performed by an experienced endoscopist using an Olympus SIF140 250 cm enteroscope. Polyps were deemed to be clinically significant when ≥1 cm (as measured at fluoroscopy, or at PE using an open biopsy forcep technique, or when occupying the majority of the lumen on CE). Patients were referred for surgery where clinically appropriate. Results: 3 patients (27%) did not tolerate nasojejunal intubation for SBE, and the procedure was performed as a barium meal with follow through. The difference between the mean number of polyps detected by SBE (0.54, range 0-1) and CE (2.63, range 0-10) approached statistical significance (p = 0.06). PE was undertaken in 8 patients (4M4F) and the mean number of polyps found was 2.42. Conclusions: These data suggest that capsule endoscopy should be the first-line investigation of the small bowel in PJS, rather than small bowel enteroclysis. In comparison with CE, SBE appears to have poor sensitivity in detecting clinically significant small bowel polyps. PE confirmed the presence of proximal polyps found on CE. CE may have underestimated the number of large polyps clustered in the proximal small bowel (as is common in PJS). CE did detect a number of distal polyps not identified on PE. Capsule endoscopy findings can be used to direct subsequent management (surgery or PE) depending on the location of the polyps.

Radiologie contrastée du tube digestif

Although barium studies were considered, for a long time, the gold standard for the morphologic diagnosis of the gastrointestinal tract, this technique has been progressively replaced by the endoscopy and, to a lesser extent, by cross-sectional imaging techniques. As would be excepted, such competition has led to improvements in barium studies, in particular, double contrast techniques which emerge as a competitive choice for the diagnostic of mucosal lesions in the gastrointestinal tract. By describing the radiographic characteristics of a lesion, the radiologist can localize the lesion either on the mucosa, on the bowel wall, or on the tissue extrinsec to bowel. This radiographic description, in addition to its localization and its size, the age of the patient, and the clinical history, enables the radiologist to make a specific diagnosis, or the most probable differential diagnosis. This chapter is a pictorial glossary that graphically displays the principal semiological aspects of gastrointestinal radiology.

Local staging of rectal cancer: assessment with double-contrast multislice computed tomography and transrectal ultrasound.

The aim of this study was to evaluate the accuracy of multislice computed tomography (MSCT) with double-contrast technique and transrectal ultrasound (TRUS) in staging of rectal carcinoma compared with histopathological confirmation. In a prospective study of 92 patients with rectal carcinoma, preoperative MSCT with negative rectal contrast (methylcellulose) and intravenous contrast was performed. Reconstructions in 3 planes were analyzed in a cine mode in picture archiving and communication (PAC) system. Analysis of rectal wall infiltration was performed preoperatively according to a modified tumor, nodes, metastases (TNM)-classification system (< or =T2/T3/T4, N0/N+, UICC/UICC I > I). MSCT imaging findings were compared with the results of TRUS and histopathology in all patients. With interactive multiplanar image viewing, the results of MSCT of depth of rectal wall invasion (T-staging) were as follows: sensitivity, specificity, positive and negative predictive values, and accuracy rate were 85%, 87%, 88%, 84%, and 86% (54/63 patients) compared with 59%, 63%, 72%, 48%, and 60% (38/63 patients), respectively, for TRUS staging in the same patients. The sensitivity, specificity, positive and negative predictive values, and accuracy rate of MSCT for perirectal nodes evaluation was 75%, 85%, 75%, 85%, and 81% (51/63 patients) compared with 55%, 71%, 50%, 74%, and 65% (41/63 patients), respectively, for TRUS in detecting metastatic lymph nodes. Preoperative double-contrast MSCT accurately indicates the exact depth of tumor infiltration and improves lymph node staging. The new technical innovations of MSCT provide superior information for preoperative staging of rectal cancer and may compete with TRUS as the standard preoperative diagnostic method.

Organ dose and conversion coefficients applied to gonads and uterus in enteroclysis with double contrast technique

Conversion coefficients are commonly used to estimate the radiation dose in projectional radiography from the dose-area product (DAP). This study investigates whether conversion coefficients can also be used for dosimetry in fluoroscopic procedures. Thermoluminescence dosimeters (TLD) were placed into an anthropomorphic phantom (Alderson Rando Phantom) to measure the dose absorbed by the gonads and uterus. A standardized enteroclysis in double contrast technique (Sellink/Herlinger) was simulated and the DAP was measured. Three examinations with 70, 80 and 90 kV were carried out with a fluoroscopy time of 15 minutes each. The relations between the DAP and the organ dose were analyzed and a linear regression was performed to determine the conversion coefficients [mSv/cGycm (2)]. The DAP and the organ dose measured by TLD were strongly correlated (r > 0.95) for all examined organs. The strong correlations between TLD-measured organ doses and DAP recommend the use of conversion coefficients for the dosimetry of fluoroscopic procedures.