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Biomedical subjects

C R Merritt

Publications and source records attributed to C R Merritt.

At least 55 records · Page 3Linked to original sources
PubMed1988

The identification of ulcerative plaque with high resolution duplex carotid scanning.

A retrospective study evaluated 50 patients who had pathologically proven intraplaque hemorrhage. The patients were pathologically divided into two groups by the presence or absence of intimal ulcerations. These two groups were then sonographically compared with regard to surface characteristics of the plaque, plaque size, size of the sonolucent area within the plaque, and location of the sonolucent area relative to the intimal surface. No defined sonographic characteristics could be used to separate these two groups of patients with heterogeneous plaques into those who had or did not have ulcerations. Most importantly, merely sonographically evaluating the surface of the plaque to determine if it was smooth or irregular could not be used as a successful means to identify which patients were at risk for ulceration.

Arteriosclerosis↗
PubMed1986

Sonographic characterization of carotid plaque: detection of hemorrhage.

By careful evaluation of the sonographic characteristics of carotid plaques, two patterns can be identified: a homogeneous pattern containing uniform echoes corresponding to dense fibrous tissue and a heterogeneous pattern containing mixed echoes and anechoic areas that represent intraplaque hemorrhage pathologically. A prospective study was conducted of 50 patients to determine the accuracy of identifying these different forms of plaque. The patients' carotid arteries were examined by a high-resolution duplex scanner before carotid endarterectomy. The plaques were evaluated carefully by vascular surgeons and pathologists for the presence of intraplaque hemorrhage. In this study, the accuracy of identifying the presence or absence of intraplaque hemorrhage with sonography was 90% (48 of 54); sensitivity, 94% (17 of 18); and specificity, 88% (27 of 31). High-resolution sonography appears to be an accurate means of identifying intraplaque hemorrhage and may ultimately be useful in identifying patients at risk for embolic disease.

Aged↗
PubMed1985

Digital imaging of the chest.

The development of effective methods for producing digital chest radiographs is essential if the totally digital radiology department of the future is to evolve. Digital radiography of the chest is now possible with a variety of techniques. The most promising approach currently in clinical use involves the use of large-area detectors composed of photostimulable phosphors read with a laser to produce high-quality digital chest images. Image processing to modify contrast and latitude of the image display as well as enhancement of selected spatial frequencies and energy subtraction is possible with digital chest radiography. The wide exposure latitude of digital image receptors may allow useful images to be obtained with significantly smaller exposure doses than those required in conventional techniques and may also be used to compensate for inadvertent overexposure, eliminating the need for repeat examinations because of errors in exposure technique. Limitations of many current systems result from inadequate resolution provided by CRT display monitors. The production of hard copy images by laser printer on small format film overcomes this problem, allowing application of digital techniques for chest radiology to be incorporated into clinical practice with images comparable in spatial resolution to those of film-screen systems.

Fluoroscopy↗
PubMed1984

Cholelithiasis in ileostomy patients.

A retrospective study of 152 ileostomates with inflammatory bowel disease (IBD) revealed that 16 patients (10.5 per cent) had diagnoses of cholelithiasis before, at the time of, or after having ileostomies. Of the remaining patients, 69 were followed for possible cholelithiasis, most of those with sonographic examination. Sixteen of this latter group of patients (23.2 per cent) were found to have cholelithiasis, usually in an asymptomatic stage. Among women over 50 years old, seven of 11 (63.6 per cent) had gallstones. Due to this high prevalence of cholelithiasis, gallbladder imaging is recommended as a part of the preoperative workup and follow-up of ileostomates. Prophylactic cholecystectomy may be carefully considered in female patients with IBD at the time of proctocolectomy.

Adolescent↗
PubMed1984

Inflammatory bowel disease and cholelithiasis: the association in patients with an ileostomy.

Sixty-nine patients were evaluated prospectively by sonography and history to determine the presence of cholelithiasis. Sixteen patients (23%) had a positive diagnosis. A control group was also prospectively evaluated. We have determined that patients above age 50 with a permanent ileostomy are at statistically significant risk of having cholelithiasis, and their risk is greater than that of a control group matched for age and sex. Radiologists should recognize this association and carefully evaluate the gallbladder of any patient with a permanent ileostomy who has abdominal pain.

Cholelithiasis↗
PubMed1984

Antenatal diagnosis of Turner's syndrome.

The prenatal identification of a cystic mass in the region of the fetal cervical neck should raise the possibility of a cystic hygroma which is commonly associated with Turner's syndrome. Differential diagnosis should also include benign cystic teratoma, meningocele, encephalocele, and meningoencephalocele. Careful sonographic evaluation of the fetus can help differentiate these possibilities.

Adult↗
PubMed1984

Sonographic detection of portal venous gas in infants with necrotizing enterocolitis.

A characteristic pattern of hepatic parenchymal and portal venous abnormalities was seen with sonography in 12 infants with necrotizing enterocolitis (NEC). In five cases these changes were seen before any radiographic abnormalities were observed. Sonography of 232 infants without NEC did not show these changes. The sonographic abnormalities are believed to be caused by small amounts of gas within the portal venous system and hepatic parenchyma. Because of the simplicity of the sonographic examination and the sensitivity and specificity of the findings, abdominal sonography may be of great value in the early evaluation of infants suspected of having NEC.

Enterocolitis, Pseudomembranous↗
PubMed1983

CT demonstration of cystadenocarcinoma of the pancreas with calcified lymphadenopathy.

We believe our patient's pancreatic lesion represents a primary macrocystic adenocarcinoma with calcified retroperitoneal lymphadenopathy. CT examination was useful in characterizing the primary tumor and evaluating the extent of disease. The presence of calcified metastatic lesions was an additional key point in the differential diagnosis.

Aged↗
PubMed1983

Intraoperative neurosurgical ultrasound: transdural and transfontanelle applications.

High-resolution real-time ultrasound scanning of 54 patients was performed with a sector scanner during a variety of neurological procedures. Scans obtained at the time of craniotomy were successful in characterizing and localizing tumors, abscesses, arteriovenous malformations, and hematomas within the brain of 15 of 16 adult patients. One attempt to visualize a brain cyst through a 15-mm burr hole was unsuccessful. Scanning of 37 infants and young children was performed through the anterior fontanelle during placement of ventricular shunts. This allowed for the accurate placement of shunts in all patients and resulted in fewer short-term and long-term complications. Intraoperative ultrasound is a practical and highly effective means of providing intraoperative localization of intracranial anatomy and disease.

Brain Diseases↗