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Biomedical subjects

L A Mack

Publications and source records attributed to L A Mack.

At least 109 records · Page 6Linked to original sources
PubMed1986

CT of sacral injury.

Eighty-eight patients with 188 sacral fractures were examined with computed tomography (CT) and conventional radiography. Four main patterns of sacral injury were defined: sacroiliac diastasis (39%), sacral and/or iliac lip fractures (25%), vertical shear fractures (25%), and comminuted fractures (5%). Initial interpretation of plain radiographs failed to define 29% of the sacroiliac joint diastases, 57% of the lip fractures, 34% of the vertical shear fractures, and 25% of the comminuted fractures. The extent of injury was better delineated with CT, and a more certain diagnosis of sacral injury was possible with CT than with radiography. Because of the higher detection rate and improved imaging of fracture configuration, CT should be performed in all patients with sacral injury.

Adolescent↗
PubMed1986

Limb-body wall complex: in utero sonographic diagnosis of a complicated fetal malformation.

Limb-Body Wall Complex is a complicated fetal malformation with the essential features of neural-tube defects, body-wall disruption, and limb abnormalities. This complex should be distinguished from other body-wall defects including omphalocele and gastroschisis since the prognosis for limb-body wall complex is uniformly poor. For 13 cases of this unusual fetal anomaly, sonographic, radiologic, and pathologic findings were correlated. Thoracic or abdominal body-wall defects, neural-tube abnormalities, severe scoliosis, positional deformities, and abnormalities of fetal membranes were consistently demonstrated on in utero sonograms. Results show that the diagnosis of limb-body wall complex can be made by prenatal sonography.

Abdominal Muscles↗
PubMed1986

A systematic approach to fetal echocardiography using real-time/two-dimensional sonography.

Improvements in the resolution of real-time scanners have facilitated examination of the fetal heart and the performance of fetal echocardiograms. The techniques for systematic examination have rarely been described in detail. Six echocardiographic views, described in this report, allow complete examination of the four cardiac chambers, as well as the valvular structures. Interatrial and interventricular septa may be visualized, as well as the great vessels.

Blood Vessels↗
PubMed1986

Intraoperative abdominal ultrasonography: initial experience with a dedicated high-resolution operative transducer.

A dedicated 8-MHz intraoperative scanning probe was used in 42 patients who underwent exploratory abdominal surgery. A variety of pathologic processes involving the liver, pancreas, bowel, and biliary and genitourinary systems were evaluated. Sonographic studies were evaluated to determine if they added new information (20 patients, 47.6 per cent), confirmed known information (20 patients, 47.6 per cent), or provided false information (two patients, 4.8 per cent). Preliminary experience with a specially developed transducer suggests that its design avoids many of the difficulties encountered with other transducers employed for this technique. Intraoperative sonography has, in many instances, the potential to simplify surgery, shorten operating time, and modify the type of surgical procedure performed.

Abdomen↗
PubMed1986

Severe nonimmune fetal hydrops with fetal survival. A case report.

A case of severe idiopathic nonimmune fetal hydrops spontaneously resolved after delivery with only basic supportive therapy. This case emphasizes that natural occurrences occasionally are responsible for successes attributed to invasive intrauterine treatments.

Adult↗
PubMed1985

Follow-up of infants receiving cranial ultrasound for intracranial hemorrhage.

Intracranial hemorrhage (ICH) was detected in 38 preterm neonates, using cranial ultrasonic (US) scanning. Forty-three preterm neonates examined during the same period but who had no cranial US evidence of ICH were also identified. Neurodevelopmental follow-up was performed at a mean age of 22.3 months on these 81 children. As a group, children with ICH demonstrated developmental indexes in the normal range but about ten points lower than children without ICH. The outcome in survivors of grade III ICH was quite similar to the outcome in survivors of grades I and II ICH. Survivors of grade IV (intraparenchymal) hemorrhage had a worse outcome. Cerebral palsy was significantly more prevalent in children with ICH. Only two thirds of children without ICH had a completely normal outcome, reinforcing the concept that factors other than ICH alone contribute to neurodevelopmental morbidity in this population.

Cerebral Hemorrhage↗
PubMed1985

US evaluation of the rotator cuff.

Ultrasonographic (US) evaluation of the moving shoulder is a new method for evaluating the integrity of the rotator cuff. In the past, contrast arthrography has provided the only nonoperative technique for demonstrating defects in the rotator cuff. We present the details of this new technique and describe 79 patients whose US results were correlated with the findings at arthrography and/or surgery. US allows evaluation of both shoulders at once, an advantage over arthrography, where usually only one side is evaluated at a single sitting. Improvements in US instrumentation, especially the introduction of high-resolution linear-array devices and the use of experienced ultrasonographers, have improved the accuracy of US. Because US is rapid, safe, noninvasive, and inexpensive, we advocate its use instead of arthrography as the routine test of rotator cuff integrity.

Adult↗
PubMed1985

Leg length determination by CT digital radiography.

CT digital radiography is a new accurate technique for measuring leg length discrepancy. It is easily performed on commercially available equipment with a radiation dose of 3-6 times less than the conventional technique. Because of the short time required to complete the examination, charges are comparable with those for existing procedures. Good correlation in total limb length measurements between this new technique and spot scanography was noted in 24 patients. CT digital radiography should be the preferred method for evaluation for limb length discrepancy, particularly in children, because of the simple technique and lowering of radiation dose.

Child↗
PubMed1985

Thoracolumbar burst fractures: CT dimensions of the spinal canal relative to postsurgical improvement.

Cross-sectional spinal canal area was measured before and after surgery in 12 patients with thoracolumbar burst fractures and canal narrowing caused by retropulsed fragments. Patients were classified into Denis type A or type B. Denis type A fractures have comminution of both end-plates of the vertebral body creating multiple smaller fractures; Denis type B fractures have comminution of the superior end-plate only with a single vertical fracture line into the inferior end-plate creating larger fragments. The degree of neurologic impairment was assessed before and after surgery using the Frankel system. There was no correlation between degree of canal narrowing and degree of neurologic impairment. The degree of spinal canal narrowing reflects the final resting position of the vertebral body fragments after trauma; during trauma, greater degrees of canal impingement may have occurred. Also, significant canal narrowing may be present without pinching of the cord or cauda equina. All patients with Denis type A fractures had near-anatomic reduction of fragments out of the spinal canal by surgery; less than half of the patients with Denis type B had good reduction. There was no correlation between reduction of retropulsed fragments and subsequent neurologic improvement. However, this should not preclude surgery as a therapeutic option: Eight of 10 patients with neurologic impairment experienced some improvement in symptoms after surgery; the other two were unchanged.

Adult↗
PubMed1985

The impact of CT CORRELATE ScoutView images on radiation therapy planning.

CORRELATE is a new computer software program for CT that enables a radiologist to mark tumor margins on traditional CT cross-sectional images and then display the outline of that same tumor on CT ScoutView images. This function is particularly useful for radiation therapy planning because CORRELATE ScoutView images are in the same longitudinal plane as simulation radiographs used for tumor localization in radiation therapy. The impact of CORRELATE on the radiation therapy planning process was measured in 83 patients with various tumors. Therapy planning was performed before and after CORRELATE information was made available to the radiation therapist. CORRELATE information caused a change in the therapy plan in 77% of the cases and increased confidence in the therapy plan in an additional 22%. CORRELATE provides a useful and accurate tool for tumor localization.

Humans↗
PubMed1985

Abnormalities of the neonatal cerebral ventricles.

High-resolution ultrasonography allows accurate assessment of ventricular size and contour in the infant, so that conditions such as hydrocephalus, holoprosencephaly, and agenesis of the corpus callosum can be diagnosed. Ventricular shunt catheter placement can be guided, and some of the complications of cerebrospinal fluid shunt systems can be identified. Infection of the ventricular fluid causes striking findings, including increased echogenicity and septation within the lumen.

Agenesis of Corpus Callosum↗
PubMed1985

Hydrops from reciprocating atrioventricular tachycardia in a 27-week fetus requiring quinidine for conversion.

A 27-week fetus with severe nonimmune hydrops was found to have a reciprocating atrioventricular tachycardia with the rate of 275 beats per minute. Maternal digitalization produced improvement without conversion. Large doses of propranolol were without effect. Twelve days later quinidine was added, and conversion to sinus rhythm occurred after only two hours and persisted to term. The infant has no heart disease. Literature review confirms digoxin as the first choice for treatment of fetal reciprocating tachycardia, with excellent transplacental passage. Propranolol has not been demonstrably effective, and has poor placental passage. Verapamil also produced poor cord blood levels in two trials. Placental passage for procainamide is uncertain, but long-term use has been unsatisfactory. Quinidine is recommended as the second drug for treatment of resistant fetal tachyrhythmias.

Adult↗
PubMed1984

Low sensitivity of sonography and cholescintigraphy in acalculous cholecystitis.

Acalculous cholecystitis is difficult to diagnose by clinical means or contrast radiography. Because sonography and cholescintigraphy have both been shown to do well in the diagnosis of calculous cholecystitis, the sensitivity of these newer imaging methods was assessed retrospectively in 33 proven cases of acalculous cholecystitis. The sensitivities to acalculous cholecystitis for sonography (67%) and for cholescintigraphy (68%) were not as high as has been reported for these tests in calculous cholecystitis. Reasons for the lower sensitivity with each test and the pathogenesis of acalculous cholecystitis are discussed.

Acute Disease↗
PubMed1984

Estimating fetal weights less than 2000 g: an accurate and simple method.

An accurate estimated fetal weight in the low-birth-weight infant can provide valuable information for the obstetrician faced with a decision concerning mode and time of delivery. Four existing equations for calculating fetal weight were analyzed and compared with data consisting entirely of infants with birth weights of 500-2000 g. A new formula, birth weight-grams = 10.1 (abdominal circumference-cm X biparietal diameter-cm) - 481, is proposed as a simple yet accurate alternative. This equation has a standard deviation of 99 g/kg.

Birth Weight↗