Double-contrast Research Articles

The role of contrast-enhanced ultrasound (CEUS) in visualizing atherosclerotic carotid plaque vulnerability: Which injection protocol? Which scanning technique?

PurposeTo correlate the degree of plaque vulnerability as determined by contrast-enhanced ultrasound (CEUS) with histological findings. Secondary objectives were to optimize the CEUS acquisition technique and image evaluation methods. Materials and methodsFifty consecutive patients, either symptomatic and asymptomatic referring to our department in order to perform carotid endarterectomy (TEA), were enrolled. Each patient provided informed consent before undergoing CEUS. Ultrasound examination was performed using high-frequency (8–14MHz) linear probe and a non-linear pulse inversion technique (mechanical index: 0.09–1.3). A double contrast media injection (Sonovue, 2mL and 4mL; Bracco, Italy) was performed. Two videotapes were recorded for every injection: early “dynamic” phase and late “flash” phase, performed with 6 high mechanical index impulses. Movies were quantitatively and qualitatively evaluated. Qualitative and quantitative evaluation were statistically compared to immunohistological diagnosis of vulnerable plaque, considered as gold standard. ResultsQualitative CEUS evaluation obtained high statistical results when compared to immunohistological results, with values of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of 94%, 68%, 87%, 85% and 86%, respectively, which became higher if considering only asymptomatic patient, with a NPV of 91%. Nevertheless, quantitative software evaluation proved less effective and could not reach similar results. ConclusionCarotid plaque enhancement assessed with CEUS well correlates with histological assessment of plaque instability. CEUS may provide valuable information for plaque risk stratification and may play a role in the indication to treatment of patients with carotid stenoses, particularly in asymptomatic population.

Vertical sleeve gastrectomy specimens have a high prevalence of unexpected histopathologic findings requiring additional clinical management

BackgroundLaparoscopic vertical sleeve gastrectomy is used with increasing frequency as a therapeutic option for morbid obesity. Before the procedure, patients undergo a rigorous preoperative evaluation including double contrast upper gastrointestinal radiographic series at our institution. Patients undergoing sleeve gastrectomy are presumed to have no significant gastric pathology. Objectives: To investigate the prevalence of histopathologic findings requiring clinical follow-up in sleeve gastrectomy specimens. Setting: University Hospital, United States. MethodsRetrospective review was conducted of all primary vertical sleeve gastrectomy specimens performed for morbid obesity at our institution from July 2008 until August 2012 (N = 248). ResultsUnanticipated findings warranting clinical follow-up were identified in 8.4% of cases and included cases of H. pylori gastritis, autoimmune gastritis with microcarcinoid formation, necrotizing vasculitis, and intestinal metaplasia. H. pylori was identified in 5.2% of all cases and in 33.3% of cases of gastritis. Neoplasms were identified at laparoscopy in 2 additional cases (0.8%). ConclusionsSurgeons and pathologists should be aware of the high prevalence of diagnoses requiring clinical follow-up in vertical sleeve gastrectomy specimens.

Patterns and Trends in Diagnostic Tests Used for Detection of Colorectal Cancer after Screening with the Immunochemical Fecal Occult Blood Test in Japan

According to the guidelines by the Japanese government, optical colonoscopy is the most strongly recommended diagnostic test after screening with the immunochemical fecal occult blood test (iFOBT), followed by double-contrast barium enema (BE) or sigmoidoscopy. Our study was to assess patterns and trends of colorectal cancer (CRC) diagnostic testing within 2 years after iFOBT. We analyzed both iFOBT results and claims data provided by employee health insurance societies in Japan from 2005 to 2010. 25,596 enrollees underwent iFOBT screening. The positive rate was 5.1%. 32.3% of those positive underwent diagnostic tests and 1.0% (12 patients) were confirmed as having cancer. The most common test was optical colonoscopy (77.2% of total tests), followed by BE (16.2%). From 2006 to 2009, the rate of optical colonoscopy for females increased from 55% to 82% and that of BE declined from 36% to 12%, while no significant changes were seen for males. Only one-third of those who tested positive underwent diagnostic test in the 2 years following screening iFOBT. As official guidelines for diagnostic testing of CRC recommend, optical colonoscopy is now the most commonly used diagnostic test after positive iFOBT result for enrollees in employee health insurance societies in Japan.

The role of local framework luminance range in the simultaneous lightness contrast illusion with double increments

In double increment Simultaneous Lightness Contrast two equiluminant squares rest on darker backgrounds that differ in luminance. Research on such displays has produced conflicting results as to whether an illusion is observed. Anchoring theory of lightness predicts no illusion with double increment displays. Here we test the hypothesis that an illusion can be predicted if the framework containing the target and the darkest background carries more weight in lightness computations. We tested two displays, one with a general white and one with a general black background. An illusion was obtained only in the first display. These results suggest that an illusion can occur with double increment displays when the global value of the targets differs from their local value, as these conditions allow different local framework weighting to affect the targets? final lightness. We propose that this parameter be added to the Anchoring Theory.

The Korean guideline for colorectal cancer screening

Colorectal cancer is the third most common cancer in Korea; it is the second most common cancer in men and the third most common in women. The incidence rate in Korea has continuously increased since 1999 when the National Cancer Registry statistics began. Currently; there are several screening modalities; that have been recommended by expert societies, including fecal occult blood test, colonoscopy, computed tomographic colonography The annual fecal immunochemical test (FIT) has been used in adults aged 50 and older as part of the National Cancer Screening Program in Korea since 2004. Although several study results from regional or national colorectal cancer screening programs in other countries have been reported, the National Cancer Screening Program in Korea has not yet been evaluated with evidence-based methods. Herein report the consensus statements on the National Screening Guideline for colorectal cancer developed by a multi-society expert committee in Korea, as follows: 1) We recommend annual or biennial FIT for screening for colorectal cancer in asymptomatic adults, beginning at 45 years of age and continuing until 80 years (recommendation B). 2) There is no evidence for the risks or benefits of FIT in adults older than 80 years (recommendation I). 3) Selective use of colonoscopy for colorectal cancer screening is recommended, taking into consideration individual preference and the risk of colorectal cancer (recommendation C). 4) There is no evidence for the risks or benefits of double-contrast barium enema for colorectal cancer screening in asymptomatic adults (recommendation I). 5) There is no evidence for the risks or benefits of computed tomographic colonography for colorectal cancer screening in asymptomatic adults (recommendation I).

Apple-core Lesion of Colon Adenocarcinoma by Barium Double Contrast Enema

Introduction: The apple-core lesion of colon depicts stenosing appearance on imaging study. It can be caused by different etiology. In this case, we have demonstrated an apple-core lesion on barium enema and the operation result revealed adenocarcinoma of colon. Case Blog: A 64-year-old female came to our hospital presented with diffuse abdominal dull pain, distension and constipation for three days. She denied vomiting, diarrhea, fever, body weight loss or change of bowel habit. Distended abdomen and diffuse tenderness without peritoneal sign were found by physical examination. There was no leukocytosis or electrolyte imbalance. KUB showed focal dilatation of transverse colon. Computed tomography (CT) revealed irregular luminal narrowing at distal transverse colon with perifocal fat stranding (Figure 1), suggestive of malignancy change. However, the initial pathology of biopsy via colonscopy was chronic non-specific colitis. Further barium double contrast enema was scheduled and showed apple-core lesion (Figure 2) over distal transverse colon. Finally, operation was arranged and the pathology elucidated adenocarcinoma of colon. The patient is well in our regular follow-up visiting. Discussion: The apple-core lesion of colon may be caused by a variety of diseases, such as adenocarcinoma [1,2], ischaemic colitis [3], infection [4,5], inflammatory colitis [6], endometriosis [7], and sequela of radiotherapy treatment [8]. Severe colonic lumen narrowing leads to bowel obstruction [9,10]. These differentials should be kept in mind and correlate with clinical manifestations to avoid misdiagnosis.

Report based on fiscal 2010 diagnostic X-ray equipment questionnaire survey (conditions of radiography)

This is the eighth investigation which has been carried out every 5 years since 1974 for the purpose of grasping the trend of X-ray devices and the radiographic condition. We gathered it up mainly on a radiographic condition, in this report. As for the chest radiography and double contrast gastrography, introduction of the flat panel detector (FPD) advanced in comparison with the last survey. Ratio of the imaging system at chest radiography was 65% for computed radiography (CR), 33% for FPD, 1% for screen/film (S/F), and 1% for others. The radiographic condition of FPD was current time product less than CR. Ratio of the imaging system at gastrography was 3% for CR, 48% for FPD, 34% for image intensifier-digital radiography (I.I.-DR), and 15% for S/F. The tube voltage and the exposure time were similar to the last survey time, but the tube current became lower. Through this survey, the change of the radiographic condition was seen in the radiography part where introduction of the FPD advanced. We think the continuous survey is necessary in future.

Features for Discriminating Normal Cases in Automated Mass Screening for Gastric Cancer Using Double Contrast X-ray Images of Stomach

Features for Discriminating Normal Cases in Automated Mass Screening for Gastric Cancer Using Double Contrast X-ray Images of Stomach

Clinicopathological characteristics of clinical early gastric cancer in the upper-third stomach

To elucidate the clinicopathological characteristics of clinically early gastric cancer in the upper-third stomach and to clarify treatment precautions. A total of 683 patients with clinical early gastric cancer were enrolled in this retrospective study, 128 of whom had gastric cancer in the upper-third stomach (U group). All patients underwent a double contrast barium examination, endoscopy, and computed tomography (CT), and were diagnosed preoperatively based on the findings obtained. The clinicopathological features of these patients were compared with those of patients with gastric cancer in the middle- and lower-third stomach (ML group). We also compared clinicopathological factors between accurate-diagnosis and under-diagnosis groups in order to identify factors affecting the accuracy of a preoperative diagnosis of tumor depth. Patients in the U group were older (P = 0.029), had a higher ratio of males to females (P = 0.015), and had more histologically differentiated tumors (P = 0.007) than patients in the ML group. A clinical under-diagnosis occurred in 57 out of 683 patients (8.3%), and was more frequent in the U group than in the ML group (16.4% vs 6.3%, P < 0.0001). Therefore, the rates of lymph node metastasis and lymphatic invasion were slightly higher in the U group than in the ML group (P = 0.071 and 0.082, respectively). An under-diagnosis was more frequent in histologically undifferentiated tumors (P = 0.094) and in those larger than 4 cm (P = 0.024). The median follow-up period after surgery was 56 mo (range, 1-186 mo). Overall, survival and disease-specific survival rates were significantly lower in the U group than in the ML group (P = 0.016 and 0.020, respectively). However, limited operation-related cancer recurrence was not detected in the U group in the present study. Clinical early gastric cancer in the upper-third stomach has distinguishable characteristics that increase the risk of a clinical under-diagnosis, especially in patients with larger or undifferentiated tumors.

The Diagnostic Yield of Double Contrast Barium Enema

Introduction: The disease of colon and rectum impose a major diagnostic challenge to the clinician. Although double contrast barium enema (DCBE) has been overshadowed by the advent of colonoscopy and the sophisticated investigations, its role in failed colonoscopies can not be disputed. Aim: Aim of this study was to evaluate the diagnostic accuracy of DCBE. Methods: Patients attending the Mid-Western Regional Hospital, Ennis for DCBE from January 2003 to December 2007 were identified from computerised database of radiology department and were studied retrospectively. The accuracy / effectiveness of the procedure were examined in terms of its completeness. The diagnostic yield for benign and malignant pathologies was determined along with primary and secondary diagnosis. Results: A total of 278 patients (159 Females and 119 Males) with mean age of 64.44 +/- 12.99 (range 25-92) attended the Hospital for DCBE. Colonic cancer were diagnosed in 15 (5.39 %) whereas diverticular disease was reported in 137 (49.28 %) patients. There were no missed pathologies and a failure rate of less than 2% was achieved in this study. Conclusion: Double contrast barium enema is a sensitive diagnostic tool in the investigation of colorectal pathologies. In view of its low failure rate, it may be used as an adjunct to commonly practiced endoscopic investigation to further increase the accuracy

Features for Discriminating Normal Cases in Mass Screening for Gastric Cancer with Double Contrast X-ray Images of Stomach

In a mass screening for gastric cancer, diagnosticians read many stomach X-ray pictures at a time. To decrease the number of reading the pictures in the mass screening, the proposed method discriminates normal cases in stomach X-ray images using the proposed features. In the normal cases, folds on the stomach wall appear in parallel in the images. Considering this characteristic, the proposed method measures parallelism of the folds in the images. Experimental results of the discriminations for 88 images where 13 abnormal cases are included have shown that the proposed features are well effective for recognizing normal cases.

Radiological findings in duodenal tuberculosis: a 15-year experience.

To evaluate the radiological findings of duodenal tuberculosis with particular emphasis on the barium findings. A retrospective analysis of 805 cases of gastrointestinal tuberculosis from January 1997 to December 2011 over a period of 15 years was conducted. Thirty two cases (4%) of duodenal tuberculosis were found. The diagnosis of duodenal tuberculosis was based on histopathology following surgery or endoscopic biopsy from the duodenum, ultrasound-guided aspiration cytology/biopsy of lymph nodes or response to anti-tubercular treatment. The patients' clinical presentation was broadly classified into obstructive features and dyspeptic features. Single and/ or double contrast upper gastrointestinal barium studies were reviewed in each case for the segment involved, presence and length of strictures, ulcerations, polypoidal masses, extrinsic impression and complications (viz. perforations and fistulae). The study included 20 males and 12 females with age range of 7-70 years (mean age 26.6 years) Twenty-seven (84.3%) patients presented with obstructive symptoms and five (15.6%) had predominantly dyspeptic symptoms. The radiological findings in patients with obstructive symptoms were duodenal strictures (n = 19), extrinsic compression (n = 10) and polypoidal intraluminal mass with luminal narrowing (n = 3). Among the patients presenting with dyspeptic symptoms, the most common findings was duodenal ulcerations (n = 3). Perforation was seen in 4 cases and fistulisation in 2 cases. A multiplicity of findings was noted in 7 patients. Barium studies though not specific for duodenal tuberculosis helped to delineate the mucosal lesions and define the nature, level, and extent of obstruction in these patients.

History, evolution, and current status of radiologic imaging tests for colorectal cancer screening.

Colorectal cancer screening is thought to be an effective tool with which to reduce the mortality from colorectal cancer through early detection and removal of colonic adenomas and early colon cancers. In this article, we review the history, evolution, and current status of imaging tests of the colon-including single-contrast barium enema, double-contrast barium enema, computed tomographic (CT) colonography, and magnetic resonance (MR) colonography-for colorectal cancer screening. Despite its documented value in the detection of colonic polyps, the double-contrast barium enema has largely disappeared as a screening test because it is widely perceived as a labor-intensive, time-consuming, and technically demanding procedure. In the past decade, the barium enema has been supplanted by CT colonography as the major imaging test in colorectal cancer screening in the United States, with MR colonography emerging as another viable option in Europe. Although MR colonography does not require ionizing radiation, the radiation dose for CT colonography has decreased substantially, and regular screening with this technique has a high benefit-to-risk ratio. In recent years, CT colonography has been validated as an effective tool for use in colorectal cancer screening that is increasingly being disseminated.

One-step patterning of double tone high contrast and high refractive index inorganic spin-on resist

A direct one-step and low temperature micro-fabrication process, enabling to realize large area totally inorganic TiO2 micro-patterns from a spin-on resist, is presented. High refractive index structures (up to 2 at 632 nm) without the need for transfer processes have been obtained by mask assisted UV lithography, exploiting photocatalytic titania properties. A distinctive feature not shared by any of the known available resists and boosting the material versatility, is that the system behaves either as a positive or as negative tone resist, depending on the process parameters and on the development chemistry. In order to explain the resist double tone behavior, deep comprehension of the lithographic process parameters optimization and of the resist chemistry and structure evolution during the lithographic process, generally uncommon in literature, is reported. Another striking property of the presented resist is that the negative tone shows a high contrast up to 19, allowing to obtain structures resolution down to 2 μm wide. The presented process and material permit to directly fabricate different titania geometries of great importance for solar cells, photo-catalysis, and photonic crystals applications.

O7.02 * RADIOSURGERY AND BRAIN METASTASES: ADEQUATE SEQUENCE OF BRAIN MRI CAN SIGNIFICANTLY CHANGE THE INTRACRANIAL DISEASE STAGING

INTRODUCTION: Accurate assessment of the exact number of brain metastases is of utmost importance in the decision-making process for the appropriate treatment. The diagnostic efficacy in the detection of additional brain metastases of a double dose contrast three-dimensional, T1-Weighted Gradient-Echo Imaging was evaluated. METHODS: Before undergoing radiosurgical treatment, patients underwent a brain magnetic resonance imaging (MRI) scan to be used during the treatment planning in order to contour the targets and to locate the brain lesions as they relate to the stereotactic frame. All the patients underwent a post-contrast study with T1-weighted, 3D Magnetization-Prepared Rapid Acquisition Gradient Echo (MP RAGE) sequence. We used a double dose of gadobenate dimeglumine and slice thickness of 0.9 mm. RESULTS: Starting from October 2012 to February 2014, we treated with Gamma Knife radiosurgery (GKRS) 62 patients with brain metastases. On the diagnostic MRI, all the patients had a number of lesions ≤4. Median time interval between diagnostic MRI scan and the day of GKRS was 11 days (range 5-20) A total of 54 additional lesions were detected on MR imaging performed in the same day of the GKRS in twenty-two patients out of 62 (35.5%). A median number of 2 additional lesions were detected (range 1-8). Among these 22 patients only 14 patients had a number of lesions ≤4 on the day of treatment. Patients with a total number of lesions ≤10 were treated with GKRS. Two patients with a total number of lesions > 10 were treated with whole brain radiotherapy (WBRT). CONCLUSIONS: A double-contrast study with T1-weighted, volumetric MPRAGE sequence may offer better staging for patients with brain metastases. In our opinion, it should be recommended in all the patients with newly diagnosed brain metastases because the detection of the real number of lesions is crucial for an adequate treatment and it also may lead to choose different therapeutic strategies.

Fe3+ ions anchored to Fe@O-MWCNTs as double impact T2 MRI contrast agents

Fe3+ ions were anchored via complexation onto the oxidized multiwall carbon nanotubes containing encapsulated iron-based nanoparticles (Fe@O-MWCNTs) yielding hybrids Fe(III)/Fe@O-MWCNTs for application as MRI contrast agents. After washing, no free Fe3+ ions were observed in the solution. A 120 mg Fe3+ was coordinated by each 1 gram of Fe@O-MWCNTs with a formation of stable hybrids. Relaxation times T1 and T2 of water protons were measured for the suspensions of hybrids. At 7.1 T relaxivity, r2 of Fe@O-MWCNT and Fe(III)/Fe@O-MWCNT was 25 and 35 s–1ml mg–1, respectively, whereas at 0.4 T r2-values were equal. Additionally, T1/T2 ratio was found in a range of 17–104, which is a promising value in the light of application of the proposed materials as potential T2 MRI contrast agents.

Additional MR contrast dosage for radiologists' diagnostic performance in detecting brain metastases: a systematic observer study at 3 T.

To evaluate the diagnostic performance of a double-dose administration of gadolinium for brain metastases at 3 T in a systematic observer test. Postcontrast MR images of 39 patients (total 104 metastases) were obtained by 3D T1-weighted sequences with both standard and cumulative double dose contrast administration. An observer test involving 9 radiologists (5 board-certified radiologists and 4 residents) was performed, and their diagnostic performance with the two doses was compared by means of sensitivity, false-positives, reading time, and a figure-of-merit. Compared to the standard dose, the double dose showed higher sensitivity (P < 0.0001), higher false-positive/case (P < 0.05), longer reading time (P < 0.05), and higher figure-of-merit (P < 0.0001). Particularly in small lesions (< 5 mm), sensitivity with the double dose (61.5%, P < 0.0001) was approximately twice as high as that with the standard dose (29.5%). Artifacts and blood vessels were the most common imaging findings resulting in false-positives. The double dose improved detection for metastases smaller than 5 mm at 3 T and thus resulted in better diagnostic performance of radiologists. However, a higher dose might result in prolonged reading time and increased false-positives, presumably due to increased vessel signals and frequency of flow-related artifacts.

Computed tomography colonography: a well-known but poorly utilized screening method.

Radiol Bras. 2014 Mai/Jun;47(3):V–VI Malignant colon neoplasm is the third cause of death for cancer in the United States of America. Many of such deaths could be avoided with the introduction of an effective screening schedule. The ideal screening test is the one that allows for an early diagnosis and, consequently the management of the disease at its early stages. The effectiveness of a screening test depends on three factors, namely: 1) the disease must be common; 2) early detection of the disease; 3) acceptance of the test by the patient. Different factors predispose to large bowel neoplasia: 1) family history of disease or large adenomatous polyp (diagnosed before the age of 60); 2) inflammatory bowel disease; 3) family history of adenomatous polyposis or nonpolypoid hereditary colorectal cancer syndromes; 4) previous history of adenomatous colon polyps. Despite the existence of specific predisponent conditions, in approximately 75% of cases it is not possible to identify a specific risk factor. Before the introduction of computed tomography colonography (CTC), several screening tests were available to detect colon polyps or neoplasms, namely, fecal occult blood test, rectosigmoidoscopy, a combinations of the mentioned methods, double contrast barium enema and colonoscopy. In 2008, the American Cancer Society, in association with the US Multi-Society Task Force on Colorectal Cancer (representing the three major American gastroenterological societies – American Society of Gastroenterology, American College of Gastroenterology, and American Society of Endoscopy) and the American College of Radiology placed CTC as a screening test for colorectal carcinoma (CRC) in association with colonoscopy, as a modality for primary prevention and early detection. Virtual colonoscopy or CTC is a relatively recent investigation method, initially described in 1994 amongst the available options for screening CRC. It is a minimally invasive computed tomography (CT) modality utilizing low radiation doses,

Evaluation of liver fibrosis with T1ρ MR imaging.

Chronic liver disease is a major public health problem worldwide. Liver fibrosis, a common feature of almost all chronic liver diseases, involves the accumulation of collagen, proteoglycans, and other macromolecules in the extracellular matrix. The accumulation of proteins in the extracellular matrix promotes the formation of scars that bridge together adjacent portal triads and central veins. Ultimately, progressive hepatic fibrosis leads to cirrhosis, a characteristic of all end-stage liver disease. Clinically, liver fibrosis usually has an insidious onset and progresses slowly over decades. Patients remain asymptomatic or have only mild, nonspecific symptoms until the development of cirrhosis (1). To date, the conventional imaging diagnostic tests available in clinical practice are not sensitive or specific enough to function as screening tests for detecting liver fibrosis. In patients with precirrhotic stages of liver fibrosis, as well as patients with early cirrhosis, the liver parenchyma usually has a normal appearance or may exhibit only subtle, nonspecific heterogeneity on conventional MR images. A number of MR imaging techniques have been investigated to identify or to assign a grade to liver cirrhosis. These include double contrast material-enhanced MR imaging (2), MR elastography (3-5), and diffusion weighted imaging (3,5,6). The reproducibility and intersite variability of these techniques have not been well established. A mechanism for magnetic resonance (MR) tissue contrast, spin-lattice relaxation time in the rotating frame (T1ρ), has been investigated in biomedical applications. In T1ρ imaging, the equilibrium magnetization, M0, established by the static magnetic field, B0, is flipped into the transverse plane first. This magnetization in the transverse plane relaxes like a normal free induction decay but in the presence of an onresonant continuous wave radiofrequency pulse, which is much weaker than B0 and is called spin-lock radiofrequency pulse. The relaxation rate constant of this transverse magnetization

ACR Appropriateness Criteria Colorectal Cancer Screening

Colorectal cancer is the third leading cause of cancer deaths in the United States. Most colorectal cancers can be prevented by detecting and removing the precursor adenomatous polyp. Individual risk factors for the development of colorectal cancer will influence the particular choice of screening tool. CT colonography (CTC) is the primary imaging test for colorectal cancer screening in average-risk individuals, whereas the double-contrast barium enema (DCBE) is now considered to be a test that may be appropriate, particularly in settings where CTC is unavailable. Single-contrast barium enema has a lower performance profile and is indicated for screening only when CTC and DCBE are not available. CTC is also the preferred test for colon evaluation following an incomplete colonoscopy. Imaging tests including CTC and DCBE are not indicated for colorectal cancer screening in high-risk patients with polyposis syndromes or inflammatory bowel disease. This paper presents the updated colorectal cancer imaging test ratings and is the result of evidence-based consensus by the ACR Appropriateness Criteria Expert Panel on Gastrointestinal Imaging. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.