Biomedical subjects

Stephanie R Wilson

Publications and source records attributed to Stephanie R Wilson.

23 records · Page 2Linked to original sources

PubMedDate not supplied

US of gastrointestinal tract abnormalities with CT correlation.

Ultrasonography (US) is often the first imaging study performed in patients with abdominal pain or vague symptoms related to the gastrointestinal tract. An awareness of the US appearances of diseases of the intestine is essential to achieve the proper diagnosis and to enable appropriate triage of cases. Pathologic processes that affect the intestine generally result in decreased peristalsis and bowel wall thickening, both of which tend to decrease the luminal gas content. These changes permit evaluation of the intestine and surrounding structures with transabdominal and transvaginal US. US is useful in diagnosis of infectious and inflammatory conditions, such as appendicitis, Crohn disease, diverticulitis, epiploic appendagitis, pseudomembranous colitis, small bowel obstruction, small bowel vasculitis, and celiac disease. US is also helpful in diagnosis of tumors, such as gastric cancer, bowel lymphoma, and colon cancer. Familiarity with the US appearances of diseases that affect the intestine may allow specific diagnosis based on the degree and distribution of bowel wall thickening and associated changes of the perienteric tissues.

Adult↗

PubMedDate not supplied

US of the peritoneum.

Familiarity with the pathophysiology of peritoneal disease is the basis of successful ultrasound (US) study of the peritoneum. The pouch of Douglas, diaphragmatic surfaces, the paracolic gutters, and the regions of the mesentery and omentum should receive careful scrutiny in the patient at risk for a peritoneal disease process. An optimal US technique requires assessment of the entire peritoneum with a transducer selected to reflect the depth of the region of interest. US may demonstrate minute quantities of free intraperitoneal fluid and is therefore capable of providing sensitive quantitative information about ascites. Qualitative information may also be inferred, as blood, pus, and neoplastic cells demonstrate correlation with particulate ascites on gray-scale US scans. Peritoneal nodules, plaques, and thickening may be detected on the visceral or parietal peritoneal surfaces, especially when high-frequency probes are used. Transvaginal study in women increases the sensitivity of US for detection of peritoneal disease. In women who have unexplained sepsis or are at risk for carcinomatosis, transvaginal scanning should routinely be added to the regular abdominal and pelvic studies regardless of the findings of those studies. Peritoneal carcinomatosis, primary peritoneal neoplasms, pseudomyxoma peritonei, and peritonitis have characteristic appearances at US.

Diagnosis, Differential↗

PubMedDate not supplied

US of liver transplants: normal and abnormal.

Whole-liver transplantation is an accepted and successful method of treating end-stage liver disease. As a result of the shortage of cadaveric livers, split-liver transplantation and living donor liver transplantation are becoming more commonplace. Ultrasonography (US) is the initial imaging modality of choice for detection and follow-up of early and delayed complications from all types of liver transplantation. Vascular complications include thrombosis and stenosis of the hepatic artery, portal vein, or inferior vena cava, as well as hepatic artery pseudoaneurysms and celiac artery stenosis. Biliary complications include leaks, strictures, stones or sludge, dysfunction of the sphincter of Oddi, and recurrent disease. Neoplastic disease in the transplanted liver may represent recurrent neoplasia or posttransplantation lymphoproliferative disorder. Parenchymal disease may take the form of a focal mass or a diffuse parenchymal abnormality. Perihepatic fluid collections and ascites are common after liver transplantation. Knowledge of the surgical technique of liver transplantation and awareness of the normal US appearance of the transplanted liver permit early detection of complications and prevent misdiagnosis.

Adult↗

PubMedDate not supplied

From the RSNA refresher courses: imaging evaluation for acute pain in the right upper quadrant.

Acute cholecystitis is the most common cause of acute pain in the right upper quadrant (RUQ), and urgent surgical removal of the gallbladder is the treatment of choice for uncomplicated disease. However, cross-sectional imaging is essential because more than one-third of patients with acute RUQ pain do not have acute cholecystitis. In addition, patients with complications of acute cholecystitis, such as perforation, are often best treated with supportive measures initially and elective cholecystectomy at a later date. Ultrasound (US) is the primary imaging modality for assessment of acute RUQ pain; US is both sensitive and specific in demonstrating gallstones, biliary dilatation, and features that suggest acute inflammatory disease. Occasionally, additional imaging modalities are indicated. Computed tomography is valuable, especially for confirming the extent and nature of the complications of acute cholecystitis. Magnetic resonance cholangiopancreatography is helpful in complicated ductal disease (eg, recurrent pyogenic cholangiohepatitis) when more detailed diagnostic information is required for treatment planning, whereas endoscopic retrograde cholangiopancreatography is used when biliary intervention is required (eg, treatment of choledocholithiasis). Successful imaging with all modalities requires familiarity with both the characteristic and the unusual features of a wide variety of pathologic conditions. In addition, potential pitfalls must be recognized and avoided.

Abdominal Pain↗

PubMedDate not supplied

Blood flow patterns in focal liver lesions at microbubble-enhanced US.

Noninvasive diagnosis of liver lesions is usually performed with contrast material-enhanced computed tomography (CT) and magnetic resonance (MR) imaging and is based on enhancement features of the arterial and portal venous phases. Ultrasonography (US) is often limited in characterizing liver lesions because color and spectral Doppler US provide limited vascular information in large patients and in small or deep lesions. However, microbubble contrast agents, together with specialized US techniques, now allow diagnosis of liver lesions based on morphologic evaluation of lesion vascularity and visualization of specific enhancement features. Microbubble contrast agents are purely intravascular, easy to administer, and well tolerated and allow sensitive real-time evaluation of blood flow in hepatic lesions. During the portal venous phase, benign lesions (eg, hemangioma, focal nodular hyperplasia) typically enhance more than the liver, whereas malignant lesions (eg, hepatocellular carcinoma, metastases) enhance less. Microbubble-enhanced US allows characterization of very small lesions that may not be accurately characterized with CT or MR imaging. Findings from initial studies suggest that microbubble-enhanced US of the liver provides enhancement information comparable to that provided by contrast-enhanced CT and MR imaging, along with real-time morphologic evaluation of lesion vascularity.

Acoustics↗