Multidetector-row helical CT and advanced postprocessing techniques for the evaluation of pancreatic neoplasms.

An important feature of multidetector-row helical computed tomography (CT) is the increased speed of scanning that permits routine use of very thin collimation and acquisition of near isometric imaging data of the abdomen within the time span of a single breath-hold. The parallel escalation in the capabilities of workstations makes feasible the practical use of advanced postprocessing techniques to create high quality volumetric imaging. This article highlights the unique contributions of multidetector-row CT and advanced postprocessing techniques to the evaluation of the pancreas and peripancreatic vascular structures and their value in the diagnosis and staging of pancreatic neoplasms.

Imaging the patient with right upper quadrant pain.

A variety of high-resolution imaging techniques are currently available for the evaluation of patients with RUQ pain. In these patients, an imaging approach that is based on identifying the presence of certain clinical signs and symptoms can aid in choosing the appropriate imaging modality and establishing the diagnosis. For patients presenting with a positive Murphy sign, sonography and biliary scintigraphy are the most useful initial imaging techniques. In patients with fever and a negative Murphy sign, a combination of sonography and contrast-enhanced CT can establish the diagnosis in most cases. And finally, in patients without fever or a positive Murphy sign, CT and MR are appropriate first-line imaging techniques.

Functional magnetic stimulation of the colon in persons with spinal cord injury.

OBJECTIVE: To evaluate the usefulness of functional magnetic stimulation (FMS) as a noninvasive method to stimulate the colon in individuals with spinal cord injury (SCI). DESIGN: A prospective before-after trial consisting of 2 protocols. SETTING: FMS laboratories of 2 SCI centers. PARTICIPANTS: Two able-bodied men and 13 men with SCI levels ranging from C3 to L1. Protocol 1 consisted of 9 subjects, 2 of whom were excluded from the analysis. Protocol 2 consisted of 4 subjects. INTERVENTION: Commercially available magnetic stimulators with round magnetic coils (MCs) were used. Protocol 1 measured the effects of FMS on rectal pressure by placing the MC on the transabdominal and lumbosacral regions. Protocol 2 consisted of a 5-week stimulation period to investigate the effects of FMS on total and segmental colonic transit times (CTTs). MAIN OUTCOME MEASURE: An increase in rectal pressure and a decrease in CTT by magnetic stimulation. RESULTS: Data were averaged and the standard error of the mean was calculated. Statistically significant changes in rectal pressure and CTT were also measured. Rectal pressures increased from 26.7 +/- 7.44cmH(2)O to 48.0 +/- 9.91cmH(2)O, p =.0037, with lumbosacral stimulation, and from 30.0 +/- 6.35cmH(2)O to 42.7 +/- 7.95cmH(2)O, p =.0015, with transabdominal stimulation. With FMS, the mean CTT decreased from 105.2 to 89.4 hours, p =.02. CONCLUSION: FMS is able to stimulate the colon and reduce CTT. FMS is a noninvasive, technological advancement for managing neurogenic bowel in patients with SCI.

Focal liver lesions: pattern-based classification scheme for enhancement at arterial phase CT.

PURPOSE: To present our early experience with a classification scheme for categorizing focal liver lesions on the basis of the enhancement patterns that they exhibit in the arterial phase of computed tomography (CT) and to determine whether particular enhancement patterns suggest particular diagnoses. MATERIALS AND METHODS: The authors reviewed arterial phase CT images in 100 consecutive patients with focal liver lesions, excluding simple cysts. The enhancement pattern of the dominant or representative lesion in each patient was classified into one of five categories-homogeneous, abnormal internal vessels or variegated, peripheral puddles, complete ring, or incomplete ring-by three radiologists blinded to the proved diagnosis. Lesions without enhancement were recorded separately. Agreement was reached by consensus in all cases. Standards of reference included findings at histologic examination, correlative imaging, or clinical and imaging follow-up. RESULTS: Ninety-two percent of the 100 lesions demonstrated arterial phase enhancement. Patterns associated with positive predictive values of 82% or greater and specificity of 80% or greater included abnormal internal vessels or variegated (hepatocellular carcinoma), peripheral puddles (hemangioma), and complete ring (metastasis). CONCLUSION: The appearance of hepatic lesions in the arterial phase of enhancement has potential use in the determination of specific diagnoses. The classification scheme used in this study may be a useful tool for the interpretation of arterial phase CT studies.

Urinary bladder pseudolesions on contrast-enhanced helical CT: frequency and clinical implications.

OBJECTIVE: The goals of this study were to define the distinguishing characteristics and frequency of urinary bladder pseudolesions that are produced as opacified urine enters the bladder during contrast-enhanced helical CT of the abdomen and to evaluate the usefulness of delayed imaging in differentiating pseudolesions from true lesions. SUBJECTS AND METHODS: Contrast-enhanced routine CT scans of 184 patients were obtained prospectively. For each patient, we also obtained 5-min delayed images of the bladder. The images were evaluated for apparent focal thickening or polypoid lesions involving the bladder wall, findings that may represent bladder neoplasia, without knowledge of the indications for the scan, the patient's clinical history, or the patient's diagnosis. Apparent lesions that were visible on routine images and entirely absent on delayed images were considered to be pseudolesions. RESULTS: Apparent lesions were identified on 20 (10.9%+/-4.5% [limits of the 95% confidence interval]) of the routine CT scans. Using delayed images, the 21 apparent lesions in these 20 patients were resolved as 13 pseudolesions and eight true lesions. Pseudolesions were present in 6.5%+/-3.6% of patients. CONCLUSION: Pseudolesions of the bladder that are indistinguishable from true lesions pose a significant clinical problem in routine contrast-enhanced helical CT of the abdomen. Delayed imaging of the bladder is useful in distinguishing pseudolesions from true lesions.

Dual-phase helical CT of locally invasive pancreatic adenocarcinoma.

Dual-phase helical CT permits imaging of the pancreas and the peripancreatic structures in the arterial dominant and portal venous phases of enhancement, providing information crucial in the assessment of the local extent of pancreatic adenocarcinoma. This essay reviews the dual-phase helical CT findings of local extension that preclude potentially curative surgery, including vascular involvement, ligamentous or mesenteric invasion, extension of the tumor to involve the stomach or duodenum, and invasion of adjacent solid organs.

Esophageal wall thickening: a CT finding in diffuse esophageal spasm.

We report three patients with esophageal wall thickening, incidentally found at CT, in whom further evaluation led to the diagnosis of diffuse esophageal spasm (DES). All cases showed smooth, symmetric, circumferential wall thickening of the distal two-thirds of the esophagus with normal periesophageal fat. No lung parenchymal abnormalities suggestive of aspiration were seen. DES, although uncommon, is another benign condition that should be included in the differential diagnosis of esophageal wall thickening detected by CT.

Dual-phase helical CT of the liver: value of arterial phase scans in the detection of small (< or = 1.5 cm) malignant hepatic neoplasms.

OBJECTIVE: Helical CT scanners now allow sequential arterial phase and portal venous phase scans of the entire liver to be obtained during a single bolus injection of contrast material. The purpose of this study was to determine if arterial phase scans improve detection of small (< or = 1.5 cm) malignant hepatic neoplasms when compared with portal venous scans alone. MATERIALS AND METHODS: Dual-phase helical CT of the liver was done in 96 patients referred for known or suspected malignant hepatic lesions. Malignant hepatic neoplasms were detected in 38 patients (27 with at least one small neoplasm), one patient had undetected metastases, one patient had a benign hepatic neoplasm, and 56 patients had no hepatic neoplasm. Proof of individual neoplasms was based on biopsy results, surgical findings, or findings on other imaging studies (primarily follow-up CT). The absence of disease was established by surgical or autopsy findings, findings on subsequent imaging studies, or a combination of clinical and laboratory data. A total of 150 ml of 60% nonionic contrast material was infused at 5 ml/sec followed by sequential arterial phase and portal venous phase helical scans of the liver. Three radiologists retrospectively reviewed the scans. Individual lesions were measured and the conspicuity of each lesion on arterial phase and portal venous phase scans was compared. The percentage of patients in whom some malignant neoplasms were detected better on the arterial phase scan was calculated using categories based on lesion size and typical tumor vascularity. RESULTS: In 10 (37%) of 27 patients who had at least one small malignant neoplasm, lesions 1.5 cm or less in diameter were only visible or were more conspicuous on the arterial phase scan. No malignant neoplasms more than 1.5 cm in diameter were visible only on the arterial phase scan. In four (11%) of 38 cases, malignant neoplasms more than 1.5 cm in diameter were more conspicuous on the arterial phase scan. The arterial phase scans improved lesion conspicuity in nine (39%) of 23 patients who had typically hypervascular neoplasms, whereas lesion conspicuity was improved in three (20%) of 15 patients who had typically hypovascular neoplasms (p = .02). The arterial phase scan resulted in the false-positive detection of lesions in two (2%) of 96 cases. CONCLUSION: Arterial phase helical CT of the liver improves detection of some small, malignant hepatic neoplasms when performed in addition to portal venous scanning. The value is greatest in those patients who have hypervascular neoplasms.

Color Doppler sonography of the cystic artery: comparison of normal controls and patients with acute cholecystitis.

Color Doppler sonography was used to evaluate the length and distribution of the cystic artery in the gallbladder wall in 115 normal adults and in 54 patients with surgically proved cholecystitis. All patients were scanned with a 5 MHz curved array transducer optimized for low volume color sensitivity. A specific attempt was made to visualize the cystic artery throughout its course. Spectral Doppler waveforms were obtained to document arterial flow. The length of the cystic artery visualized was analyzed as a quartile percentage length of the anterior gallbladder wall. The distribution of the cystic artery flow also was analyzed in specific quartiles. Of 54 patients with acute cholecystitis, 26% had cystic artery length greater than half of the anterior gallbladder wall, compared with 2% of 115 normal controls (P < 0.001); 19% of patients with cholecystitis had flow in the distal (fundal) quartile, compared to 0% of normal controls (P < 0.0001). Although the presence or absence of flow in the gallbladder is not a reliable finding to establish the diagnosis of acute cholecystitis, length of cystic artery visualized is a potentially useful criterion to suggest the diagnosis of acute cholecystitis, especially in cases in which flow in the distal fundal quartile of the gallbladder. The usefulness of color Doppler sonography in acute cholecystitis is limited owing to the fact that it is insensitive, and many patients with cholecystitis have no detectable flow or have normal flow patterns.

Hepatic focal nodular hyperplasia: findings with color Doppler sonography.

Color Doppler sonographic images of five patients with a total of six lesions of FNH were reviewed. All cases were confirmed pathologically. All six lesions showed increased intralesional flow in comparison to surrounding liver parenchyma on color Doppler sonography. Four of the six lesions showed significant peripheral flow; two of the six lesions showed central flow radiating peripherally from a central vessel. We conclude that increased color Doppler flow may be a characteristic feature of FNH. Increased internal flow has also been reported in HCC and hepatic metastatic disease. Considerable overlap is seen in color Doppler flow patterns. However, in patients clinically at low risk for malignancy, detection of a liver mass with increased color Doppler flow should suggest the diagnosis of FNH.

Color flow Doppler characterization of focal hepatic lesions.

OBJECTIVE: The purpose of this study was to determine the sensitivity and specificity of color flow Doppler sonography for the specific diagnosis of focal hepatic lesions. SUBJECTS AND METHODS: Color flow Doppler images of 118 focal hepatic lesions in 108 patients were analyzed prospectively. In most patients, liver disease was suspected or known to be present before the Doppler images were obtained. Experienced sonologists obtained and interpreted all sonograms. The lesions were classified, according to their color flow pattern, into two main categories: lesions with internal vascularity and lesions with no internal vascularity. The color flow Doppler pattern of each lesion was correlated with the diagnosis of the lesion on a lesion-by-lesion basis. One hundred two lesions were proved by biopsy and 16 lesions were confirmed by evaluation with other imaging techniques. Lesions included 29 hepatocellular carcinomas, 64 metastases, one cholangiocarcinoma, and 24 benign lesions. The sensitivity and specificity of vascularity as shown by color Doppler imaging in the diagnosis of hepatocellular carcinoma were determined. RESULTS: The majority of hepatocellular carcinoma lesions (76%) had internal vascularity. Most of the metastases (67%) and benign lesions (75%) had no internal vascularity. When the presence of internal vascularity was used as the discriminating criterion, the sensitivity of color flow Doppler findings for the diagnosis of hepatocellular carcinoma was 0.76. The specificity of internal vascularity for the diagnosis of hepatocellular carcinoma vs other focal lesions was 0.69; for hepatocellular carcinoma vs metastases it was 0.67. CONCLUSION: Although most hepatocellular carcinomas have internal vascularity on color flow Doppler images, a significant number of metastases also have internal vascularity. This overlap limits the usefulness of color flow Doppler imaging for distinguishing hepatocellular carcinoma from metastatic tumors.

Functional abnormalities of the gastrointestinal tract in patients with spinal cord injuries: evaluation with imaging procedures.

One quarter of patients with spinal cord injuries eventually have severe chronic gastrointestinal symptoms. Because there are about 1.5 million such patients in the United States, major chronic gastrointestinal symptoms will develop in approximately 400,000 patients, all of whom are likely to need the services of radiologists. These gastrointestinal abnormalities, however, are quite different from the gastrointestinal problems that occur in the general population. For this reason, the imaging methods used for diagnosis in these patients are also different from those used with persons who do not have spinal cord injuries. The purpose of this review is to describe the role of diagnostic imaging in patients with severe chronic gastrointestinal symptoms associated with spinal cord injury.

Congenital anomalies of the inferior vena cava: embryogenesis and MR features.

This article describes the MR appearances of the six most common congenital anomalies of the inferior vena cava. As a basis for understanding those anomalies, it describes the embryology of the inferior vena cava, based on an actual study of embryos and fetuses. The article takes a fresh look at the original research in this area, discusses the possible embryogenesis of the relevant anomalies, and describes different opinions on that subject, where different opinions exist.

Intraluminal contrast enhancement and MR visualization of the bowel wall: efficacy of PFOB.

Efforts to develop satisfactory intraluminal gastrointestinal contrast agents for magnetic resonance (MR) imaging have focused on depicting only the bowel lumen to exclude possible involvement by a pathologic process. To determine whether the bowel wall can be adequately imaged with use of the contrast agent and whether bowel wall visualization is a better index of the utility of the contrast agent for MR imaging, perfluoroocytlbromide (PFOB) was studied in human subjects. Twenty consecutive patients referred for abdominal or pelvic MR imaging were selected. All patients were given 400-1,000 mL of PFOB orally. MR imaging was performed at 0.38 and 1.5 T with T1- and T2-weighted spin-echo pulse sequences before and after administration of PFOB. The images were graded independently by three blinded readers. All readers reported significantly superior conspicuity of the bowel lumen and wall after PFOB than before PFOB administration (P less than .002). Among the post-PFOB studies, those with superior bowel wall visualization demonstrated superior overall image quality. In three patients, lesions were optimally demonstrated because the relationship of the process to the bowel wall, rather than just to the lumen, was identified. In two patients, masses arising within the bowel wall could be identified prospectively only when the bowel wall was adequately imaged. The authors conclude that while lumen identification is improved with PFOB, its greatest clinical utility may be in facilitating intestinal wall visualization.

Chronic gastrointestinal problems in spinal cord injury patients: a prospective analysis.

Detailed interviews of 127 consecutive patients seen by our spinal cord injury service were performed in order to determine the prevalence and characteristics of chronic gastrointestinal problems in spinal cord injury (SCI) patients. Chronic gastrointestinal problems were defined as recurring symptoms that were significant enough to alter lifestyle or require chronic treatment. Thirty-four (27%) of the patients had a significant chronic gastrointestinal problem. The limited manner through which SCI patients can manifest symptoms resulted in complaints which were characteristically quite vague. The most common problems that impaired quality of life were poorly localized abdominal pain (14%) and difficulty with bowel evacuation (20%). Hemorrhoids (74%), abdominal distention (43%), and autonomic hyperreflexia arising from the gastrointestinal tract (43%) were also very common, but had a lesser impact on lifestyle. Twenty-three percent of our population required at least one admission to the hospital for a gastrointestinal complaint following their injury. The prevalence of chronic gastrointestinal symptoms increased with time after injury, suggesting that these problems are acquired, and may therefore be avoided by the adoption of certain chronic care routines. Chronic gastrointestinal problems in SCI patients merit more study because they are: 1) very different from those in the general population, 2) responsible for a disproportionately great amount of morbidity in these patients, 3) potentially preventable.

Esophagography and esophagoscopy. Comparison in the examination of patients with head and neck carcinoma.

We carried out a prospective, double-blind study at three institutions, comparing esophagography with esophagoscopy for the detection of simultaneous cancer of the esophagus in patients with other squamous cell cancers of the head and neck. The goal was to determine whether esophagography and esophagoscopy are necessary for the examination of patients before treatment. One hundred eighty-two patients were studied; both examinations were done in 148 patients. Twenty-one patients could not undergo esophagoscopy; esophagography was inadequate in 9 patients; 4 patients could have neither examination. Concordance was noted between the two procedures in 86.5% of patients. Sixty-five percent were normal, and 21.5% were abnormal. One esophageal cancer was found in this series that was diagnosed by both methods. Our data suggest that esophagoscopy and esophagography may be complementary in evaluating squamous cell carcinoma of the head and neck in patients before treatment. Esophagography alone was useful in patients in whom esophagoscopy could not be performed.

Colostomy as treatment for complications of spinal cord injury.

We reviewed our experience with colostomy performed in 20 spinal cord injury (SCI) patients to determine the effectiveness and safety of colostomy when it is performed for a late complication of SCI. Objective evaluation of gastrointestinal function, ie, colonic transit time and anorectal manometry, was performed in six patients with chronic gastrointestinal complaints to identify the site and severity of bowel dysfunction. Twelve patients had colostomy performed for chronic gastrointestinal problems, seven as an adjunct in the treatment of perineal pressure ulcers, and one for rectal cancer. When patients with difficult bowel evacuation or incontinence were considered, colostomy reliably simplified bowel care, relieved abdominal distention, and prevented fecal incontinence. The amount of time spent on bowel care decreased from an average of 98.6 min/day to 17.8 min/day (p less than .05) after colostomy. When performed as an adjunct in the treatment of pressure ulcers, colostomy provided a dry, clean environment, and seven of seven ulcers healed. Colostomy was well accepted by all patients; all patients with chronic gastrointestinal complaints reported that colostomy improved the quality of their lives. Objective testing differentiated between failure of the colon to adequately transport material to the rectum and inability to adequately evacuate the rectum. Testing was useful in choosing the level at which a colostomy was created, and, in one instance, it identified a specific syndrome (ischemic proctitis) which required colostomy.