Fuel property modeling by high-speed gas chromatography coupled with partial least squares data analysis.

Partial least squares (PLS) regression is a valuable chemometric tool for property prediction when coupled with gas chromatography (GC). Since the separation run time and stationary phase selection are crucial for effective PLS modeling, we study these GC parameters on the prediction of viscosity, density and hydrogen content for 50 aerospace fuels. Due to the diversity of compounds in the fuels (primarily alkanes, cycloalkanes, and aromatics), we explore both polar and non-polar stationary phase columns.

Optimizing column-to-column retention time alignment in high-speed gas chromatography by combining retention time locking and correlation optimized warping.

We examine and then optimize alignment of chromatograms collected on nominally identical columns using retention time locking (RTL), an instrumental alignment tool, and software-based alignment using correlation optimized warping (COW). For this purpose, three samples are constructed by spiking two sets of analytes into a base test mixture. The three samples are analyzed by high-speed gas chromatography with four nominally identical columns and identical separation conditions.

Comparison of MDCT protocols in trauma patients with suspected splenic injury: superior results with protocol that includes arterial and portal venous phase imaging.

Purpose: We aimed to determine which intravenous contrast-enhanced multidetector computed tomography (MDCT) protocol produced the most accurate results for the detection of splenic vascular injury in hemodynamically stable patients who had sustained blunt abdominal trauma.

Methods: We retrospectively reviewed 88 patients from 2003 to 2011 who sustained blunt splenic trauma and underwent contrast-enhanced MDCT and subsequent angiography. Results of MDCT scans utilizing single phase (portal venous only, n=8), dual phase (arterial + portal venous or portal venous + delayed, n=42), or triple phase (arterial + portal venous + delayed, n=38) were compared with results of subsequent splenic angiograms for the detection of splenic vascular injury.

Repeatability of 18F-FDG PET/CT in Advanced Non-Small Cell Lung Cancer: Prospective Assessment in 2 Multicenter Trials.

Unlabelled: PET/CT with the glucose analog (18)F-FDG has several potential applications for monitoring tumor response to therapy in patients with non-small cell lung cancer (NSCLC). A prerequisite for many of these applications is detailed knowledge of the repeatability of quantitative parameters derived from (18)F-FDG PET/CT studies.

Methods: The repeatability of the (18)F-FDG signal was evaluated in 2 prospective multicenter trials.

CT colonography for the detection of nonpolypoid adenomas: sensitivity assessed with restricted national CT colonography trial criteria.

Objective: The purpose of this study was to determine the prevalence of nonpolypoid adenomas and the sensitivity of CT colonography (CTC) in their detection by use of the restricted criteria of height-to-width ratio<50% and height elevation≤3 mm.

Materials And Methods: In the National CT Colonography Trial (American College of Radiology Imaging Network protocol 6664), a cohort of 2531 participants without symptoms underwent CTC and screening colonoscopy. The CTC examinations were interpreted with both 2D and 3D techniques.

The National CT Colonography Trial: assessment of accuracy in participants 65 years of age and older.

Purpose: To conduct post-hoc analysis of National CT Colonography Trial data and compare the sensitivity and specificity of computed tomographic (CT) colonography in participants younger than 65 years with those in participants aged 65 years and older.

Materials And Methods: Of 2600 asymptomatic participants recruited at 15 centers for the trial, 497 were 65 years of age or older. Approval of this HIPAA-compliant study was obtained from the institutional review board of each site, and informed consent was obtained from each subject.

National CT colonography trial (ACRIN 6664): comparison of three full-laxative bowel preparations in more than 2500 average-risk patients.

Objective: The purpose of our study was to compare the effect of three different full-laxative bowel preparations on patient compliance, residual stool and fluid, reader confidence, and polyp detection at CT colonography (CTC).

Subjects And Methods: A total of 2531 patients underwent CTC followed by colonoscopy for the American College of Radiology Imaging Network (ACRIN) National CTC Trial. Of this total, 2525 patients used one of three bowel preparations with bisacodyl tablets and stool and fluid tagging: 4 L of polyethylene glycol (PEG); 90 mL of phosphosoda; or 300 mL of magnesium citrate.

ACRIN CT colonography trial: does reader's preference for primary two-dimensional versus primary three-dimensional interpretation affect performance?

Purpose: To determine whether the reader's preference for a primary two-dimensional (2D) or three-dimensional (3D) computed tomographic (CT) colonographic interpretation method affects performance when using each technique.

Materials And Methods: In this institutional review board-approved, HIPAA-compliant study, images from 2531 CT colonographic examinations were interpreted by 15 trained radiologists by using colonoscopy as a reference standard. Through a survey at study start, study end, and 6-month intervals, readers were asked whether their interpretive preference in clinical practice was to perform a primary 2D, primary 3D, or both 2D and 3D interpretation.

Frequency and importance of small amount of isolated pelvic free fluid detected with multidetector CT in male patients with blunt trauma.

Purpose: To retrospectively determine the frequency and importance of a small amount of isolated pelvic free fluid seen at multidetector computed tomography (CT) in male patients who have blunt trauma without an identifiable cause.

Materials And Methods: Institutional review board approval was obtained, and the requirement for informed consent was waived for this HIPAA-compliant study. One thousand male patients with blunt trauma who underwent abdominopelvic CT at a level 1 trauma center between January 2004 and June 2006 were entered into this study.

Can radiologist training and testing ensure high performance in CT colonography? Lessons From the National CT Colonography Trial.

Objective: The objective of this article is to describe the experience of the National CT Colonography Trial with radiologist training and qualification testing at CT colonography (CTC) and to correlate this experience with subsequent performance in a prospective screening study.

Subjects And Methods: Ten inexperienced radiologists participated in a 1-day educational course, during which partial CTC examinations of 27 cases with neoplasia and full CTC examinations of 15 cases were reviewed using primary 2D and 3D search. Subsequently 15 radiologists took a qualification examination composed of 20 CTC cases.

Blunt bowel and mesenteric injury: MDCT diagnosis.

Multidetector computed tomography (MDCT) has emerged as the imaging modality of choice for evaluating the abdomen and pelvis in trauma patients. MDCT readily detects injury of the solid organs as well as direct and indirect features of bowel and/or mesenteric injury-an important advance given that unrecognized bowel and mesenteric injuries may result in high morbidity and mortality. Nonetheless, challenges persist in the interpretation of abdominal and pelvic CT images in trauma patients.

Accuracy of CT colonography for detection of large adenomas and cancers.

Background: Computed tomographic (CT) colonography is a noninvasive option in screening for colorectal cancer. However, its accuracy as a screening tool in asymptomatic adults has not been well defined.

Methods: We recruited 2600 asymptomatic study participants, 50 years of age or older, at 15 study centers.

CT colonography: false-negative interpretations.

Purpose: To retrospectively evaluate if false-negative interpretations at computed tomographic (CT) colonography are due to observer error.

Materials And Methods: This study was HIPAA compliant and had institutional review board approval, with waiver of informed consent. An initial unblinded review of CT colonographic image data was used to generate reconciliation reports for all false-negative polyp candidates 6.

Congenital anomalies and normal variants of the pancreaticobiliary tract and the pancreas in adults: part 2, Pancreatic duct and pancreas.

Objective: The purpose of this article is to highlight the imaging features of congenital anomalies and normal variants of the pancreatic duct and the pancreas using contemporary imaging techniques such as MR cholangiopancreatography (MRCP), MRI, and helical CT.

Conclusion: Congenital anomalies and normal variants of the pancreatic duct and the pancreas may be clinically significant and may create a diagnostic challenge. Recognition of the updated imaging features of these entities is important in clinical management and for avoiding misdiagnosis.

Congenital anomalies and normal variants of the pancreaticobiliary tract and the pancreas in adults: part 1, Biliary tract.

Objective: The purpose of this article is to highlight the imaging features of congenital anomalies and normal variants of the biliary tract with contemporary imaging techniques such as MR cholangiopancreatography (MRCP), MRI, and helical CT.

Conclusion: Recognizing findings of congenital anomalies and normal variants of the biliary tract at MRCP, MRI, and helical CT, and knowledge of the clinical significance of each entity, are important for establishing a correct diagnosis and in guiding appropriate clinical management.

Prospective comparison of patient experience with colon imaging tests.

Purpose: Patient experience varies with the currently available colon imaging tests, including air contrast barium enema, computed tomographic colonography, and colonoscopy. We examined differences in patient experience with colon imaging tests and whether they varied with gender, age, and race.

Subjects And Methods: Patients with fecal occult blood, hematochezia, iron-deficiency anemia, or a family history of colon cancer underwent air contrast barium enema followed 7 to 14 days later by computed tomographic colonography and colonoscopy.

Helical CT evaluation of acute right lower quadrant pain: part II, uncommon mimics of appendicitis.

Objective: The purpose of our pictorial essay is to highlight the helical CT features of uncommon mimics of appendicitis and to provide clues to differentiate them from appendicitis.

Conclusion: Uncommon mimics of appendicitis create a diagnostic challenge in patients with right lower quadrant pain. Recognition of the helical CT features of uncommon mimics of appendicitis is important in clinical management and avoiding unnecessary laparotomy.

Helical CT evaluation of acute right lower quadrant pain: part I, common mimics of appendicitis.

Objective: The purpose of our pictorial essay is to present common mimics of appendicitis as noted on helical CT in patients with right lower quadrant pain and to highlight the features that provide clues to the diagnosis.

Conclusion: Recognition of the findings of common diseases that simulate acute appendicitis on helical CT, along with features that help to differentiate these entities from appendicitis, is important in establishing a correct diagnosis and in guiding appropriate therapy.

Prospective comparison of air-contrast barium enema and colonoscopy in patients with fecal occult blood: a pilot study.

Background: The utility of air-contrast barium enema and colonoscopy for evaluation of the colon has been debated. Air-contrast barium enema is less expensive and invasive than colonoscopy, but it also is less sensitive and specific. Further, although air-contrast barium enema may be less painful than colonoscopy, it often is poorly tolerated by patients.

Bronchobiliary fistula after liver transplantation.

This report describes the imaging findings of the first reported case of a bronchobiliary fistula that developed as a complication of liver transplantation. The diagnosis was confirmed by the aspiration of bile from the bronchus.

Blunt trauma to the gastrointestinal tract: CT findings with small bowel and colon injuries.

The CT diagnosis of bowel injury is difficult and warrants an organized approach. Careful scrutiny of CT images for extraluminal gas or fluid and bowel wall thickening is required. Review of images of the entire abdomen and pelvis using lung window settings is recommended, followed by the analysis using soft tissue window settings.