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Biomedical subjects

F C Laing

Publications and source records attributed to F C Laing.

At least 73 records · Page 4Linked to original sources
PubMed1986

Extrapancreatic spread of acute pancreatitis: new observations with real-time US.

Real-time ultrasonography (US) was compared with abdominal computed tomography (CT) in 40 patients with moderate to severe acute pancreatitis. Emphasis was placed on the ability of US to disclose peripancreatic involvement of the anterior pararenal spaces, lesser sac, and transverse mesocolon. When a realtime US scanning technique emphasizing semierect patient positioning and coronal views was used, 20 of 26 lesions in the anterior pararenal space (77%) and 14 of 14 abnormalities in the lesser sac (100%) were visualized. Abnormalities in the transverse mesocolon, however, were poorly detected on US scans. Ten patients (25%) in the study had extrapancreatic abnormalities missed by US. CT remains the imaging method of choice in patients with clinically moderate to severe pancreatitis. In patients with mild pancreatitis, the real-time US technique we describe improved extra-pancreatic visualization compared with previous studies using static scanners. A new US observation of perivascular spread of acute pancreatitis around the splenic and portal veins is described.

Acute Disease↗
PubMed1986

Biliary dilatation: defining the level and cause by real-time US.

In a 15-month period, 110 patients with subsequently proved biliary dilatation were evaluated with ultrasound (US). The level of dilatation was defined as pancreatic, suprapancreatic, or at the level of the porta hepatis. Causes of dilatation included pancreatitis, choledocholithiasis, neoplasm, and stricture. The distal duct was examined initially on transverse scans obtained with the patient in a semierect right posterior oblique position; the proximal duct was then examined on longitudinal scans obtained with the patient in a supine left posterior oblique position. When this scanning technique was used, US indicated the level of dilatation in 91.8% of cases and suggested the correct cause in 70.9%. Because this approach markedly improves US visualization of the intrapancreatic bile duct, distal obstructing lesions, which are the most common, can be optimally examined.

Bile Duct Diseases↗
PubMed1986

Technical factors responsible for "placental migration": sonographic assessment.

Whether placental migration occurs is debatable. To determine the incidence of placenta previa in early pregnancy and the frequency of placental migration, a retrospective analysis was undertaken of 2,087 consecutive obstetrical sonograms obtained during a 23-month period. Among 849 patients scanned between 14 and 26 weeks after conception, placenta previa was diagnosed using ultrasonography (US) in 53 patients (6.2%). This diagnosis was confirmed at surgery in 15 patients (1.8%); there were 12 cases of central previa and three cases of partial previa. Retrospective analysis revealed that in 25 cases, technical factors, such as an overly distended urinary bladder (19 cases) or focal uterine contractions (six cases), were responsible for the false-positive diagnoses. In the 13 remaining patients, however, there were no obvious technical difficulties to account for the diagnosis of previa. Migration did not occur in any of the patients with central previa. It appears that placental migration may occur, although less frequently than has previously been reported. Furthermore, this study suggests that migration does not occur in patients with central previa.

False Positive Reactions↗
PubMed1986

Plastic wrap for US transducer sterility or sanitization.

Commercially available plastic wrap can be used to encase an ultrasound transducer for sanitization purposes. If sterility is required, an individual piece of plastic wrap can be gas sterilized before the transducer is covered with it. This technique does not degrade or temporally limit the use of the transducer, it is easy to perform, and the materials are readily available.

Acoustics↗
PubMed1986

Abdominal CT in acquired immunodeficiency syndrome.

Acquired immunodeficiency syndrome (AIDS) is a lethal infectious disease that has reached epidemic proportions in urban centers of the United States. Intraabdominal opportunistic infections and malignancies are common features of this syndrome. A prodromal phase or possibly milder form of infection is known as the AIDS-related complex. Abdominal computed tomography (CT) in patients with AIDS-related complex often demonstrates a triad of mild retroperitoneal and mesenteric adenopathy, splenomegaly, and perirectal inflammation. Lymph node enlargement greater than 1.5 cm is unusual in the AIDS-related complex and should prompt CT-guided biopsy. Abdominal adenopathy (greater than 1.5 cm) in AIDS, in our experience, is most commonly related to non-Hodgkin lymphoma, Kaposi sarcoma, or infection with Mycobacterium avium-intracellulare. In most instances, CT-guided biopsy with appropriate staining technique can readily distinguish these entities. However, the subtyping of non-Hodgkin lymphoma by fine-needle aspiration biopsy alone remains controversial. Unusual features of abdominal malignancies are common in AIDS. These include a purely lymphadenopathic form of AIDS-related Kaposi sarcoma and a predilection for extranodal sites of lymphoma in AIDS. In general, patients with AIDS-related lymphoma present with advanced stages of disease with highly malignant histologic subtypes. Abdominal CT may be useful clinically for diagnosing intraabdominal complications of AIDS.

Abdominal Neoplasms↗
PubMed1986

CT in the management of periappendiceal abscess.

Abdominal CT was the primary diagnostic method used to evaluate 40 patients with suspected periappendiceal abscess. Its subsequent impact on patient management was then analyzed for several categories of clinical presentation, including patients with and without a palpable right-lower-quadrant mass and postoperative patients. CT was reliable in distinguishing periappendiceal abscesses from phlegmons; 17 of 18 patients with phlegmons responded promptly to antibiotic therapy alone without need for surgery. Patients with larger, poorly localized abscesses underwent early surgical drainage. CT was successful in guiding percutaneous catheter drainage (nine patients) or aspiration (one patient) of well-localized periappendiceal abscesses in 10 of 11 patients. One attempted catheter drainage guided by sonography was technically unsuccessful. In patients without a palpable right-lower-quadrant mass, CT was helpful in establishing the diagnosis of periappendiceal inflammation. However, there were three false-positive diagnoses in patients with pericecal fluid collections including a ruptured cecal lymphoma, a ruptured cecal diverticulum, and a ruptured corpus luteum cyst. A diagnostic approach with CT is presented in patients with suspected periappendiceal abscess.

Abscess↗
PubMed1985

High resolution scrotal ultrasonography: a highly sensitive but nonspecific diagnostic technique.

We compared surgical and pathological findings to those of preoperative scrotal ultrasonography in 50 consecutive patients undergoing surgical exploration for testicular trauma, tumors or benign atraumatic conditions. An inhomogeneous parenchymal echo pattern was the single most reliable predictor of a parenchymal abnormality. Large scrotal hematomas may preclude adequate visualization of the parenchyma and early testicular torsion may exhibit a normal parenchymal echo pattern. Except for early torsion, no false negative predictions of the state of the parenchyma were made.

Adolescent↗
PubMed1985

Ultrasound versus excretory urography in evaluating acute flank pain.

To determine the role of ultrasound (US) in patients with acute flank pain and suspected acute urinary tract obstruction, a prospective study was performed on 20 patients comparing US with emergency excretory urography. US was not as sensitive as excretory urography for diagnosing hydronephrosis, for detecting ureteral or renal calcification, or for diagnosing forniceal rupture. Although US is an effective screening modality for hydronephrosis in patients with chronic renal obstruction, it is not useful for evaluating patients with acute flank pain in whom acute obstruction may be present. In this group of patients, excretory urography remains the examination of choice.

Acute Disease↗
PubMed1985

Sensitivity of sonography in pyonephrosis: a reevaluation.

OFF sonographic features distinguishing randomly selected cases of simple hydronephrosis (34 patients) from pyonephrosis (16 patients) were reviewed in 50 patients. Fluid-fluid levels and coarse medium-intensity echoes within the renal collecting system were highly reliable findings for pyonephrosis in 10 patients. However, in six patients with proven pyonephrosis, the renal collecting system either was anechoic (four patients) or contained low-level echoes (two) that were difficult to distinguish from artifacts. Although the specificity for diagnosing pyonephrosis was 100%, the sensitivity was only 62%. Because of the consequences of misdiagnosis, sonographically guided diagnostic needle aspiration may still be required in patients with urosepsis and significant hydronephrosis.

Adult↗
PubMed1985

Early gestation: correlation of HCG levels and sonographic identification.

Previous reports have indicated that an intrauterine gestational sac is not usually detected when the maternal serum human chorionic gonadotropin (HCG) is less than 6000 mIU/ml. In order to evaluate this observation, maternal serum HCG concentrations were correlated with sonographic uterine findings in 49 patients with normal early intrauterine pregnancies. Of 37 patients in whom a gestational sac was seen, simultaneous HCG levels were 1800 mIU/ml or more in 36 cases and 357 mlU/ml in one case. In 12 cases in which a gestational sac was not detected, the serum HCG levels were 1400 mIU/ml or less. Thirteen patients had HCG levels of less than 6000 mlU/ml. A linear relation was found between gestational sac size and the exponential rise of HCG levels in early pregnancy (p less than 0.001). Of the 13 patients in whom HCG levels were less than 6000 mIU/ml, the gestational sac measured 10 mm or less in each case. Currently, a gestational sac is always seen when the HCG level is greater than 1800 mIU/ml. Comparison of serum HCG levels with sonographic detection of the gestational sac seems to be a useful method of evaluating early pregnancy.

Amnion↗
PubMed1985

Sonography of ovarian fibromas.

Sonographic findings are described in four women with ovarian fibromas. Three of the four women were postmenopausal. Three had only minimal symptoms; the other presented with acute right lower quadrant pain caused by torsion of the tumor. The tumors were large, ranging from 9 to 16 cm in diameter. A distinctive sonographic appearance was found, with a predominantly hypoechoic, solid mass producing striking sound attenuation.

Adult↗
PubMed1985

Sonographic differentiation of enlarged hepatic arteries from dilated intrahepatic bile ducts.

Identifying parallel tubular structures within the liver by sonography has been regarded as a sensitive and specific sign of intrahepatic duct dilatation. Eight cases are reported in which parallel tubes within the liver were shown not to represent dilated ducts on computed tomography, but rather enlarged hepatic arteries due to increased blood flow. All eight patients had a history of alcoholism and/or cirrhosis and had at least one ancillary sign of portal hypertension. The sonographic findings in these eight patients were compared with similar findings in 12 other patients who were subsequently found to have true intrahepatic bile duct dilatation. Sonographic features that were helpful in distinguishing these two groups are described.

Bile Ducts, Intrahepatic↗
PubMed1985

A tandem guide for renal biopsy.

Percutaneous renal biopsy with direct ultrasound guidance can minimize complications of the biopsy procedure. Presently, many laboratories use ultrasound to localize the kidney, and to calculate the appropriate depth and angle for biopsy needle placement. The actual biopsy, however, is performed blindly. A modification of this technique is presented wherein a 22-gauge guide needle is directed into the kidney using direct ultrasound visualization. This needle serves as a tandem guide for the biopsy needle. The technique reduces the number of unsuccessful needle passes, and minimizes the time required for the procedure, patient discomfort, and potential morbidity.

Adolescent↗
PubMed1984

Diagnostic evaluation of patients with suspected cholecystitis.

In this article, imaging techniques for examining patients with suspected cholecystitis are discussed. In particular, acute cholecystitis and the roles of ultrasonography and radionuclide imaging are stressed, including each of their specific advantages and limitations.

Cholecystitis↗