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Biomedical subjects

L A Mack

Publications and source records attributed to L A Mack.

At least 55 records · Page 3Linked to original sources
PubMed1990

Diagnosis of inflammatory bowel disease with ultrasound. An in vitro study.

Transabdominal ultrasound is frequently used to detect complications of inflammatory bowel disease. It has been proposed that ultrasound can distinguish between ulcerative colitis and Crohn's disease based on the degree of thickening and changes in the layered structure of the intestine. The authors evaluated the ability of ultrasound to distinguish between ulcerative colitis, Crohn's colitis, and normal colon by blindly comparing images made of resected colon specimens. The histologic interpretation of precisely the same area of tissue that was imaged was compared with the blinded image interpretation. Images from all 18 colitis specimens were correctly interpreted as being abnormal because of increased submucosal and overall wall thickness. Published ultrasound criteria for distinguishing between Crohn's disease and ulcerative colitis based on overall wall thickness and indistinctness of layers were inaccurate in 4 of 15 specimens and indeterminate in 3 cases. Ultrasound appears to be accurate in distinguishing normal from inflamed colon, but ultrasound findings alone should not be used to determine the cause of bowel inflammation.

Colitis, Ulcerative↗
PubMed1990

Sonography of facial features of alobar and semilobar holoprosencephaly.

Twenty-seven cases of alobar/semilobar holoprosencephaly were reviewed to determine and classify the associated facial abnormalities detected with prenatal sonography. All but one case were diagnosed prospectively with sonography. Facial abnormalities were present in 24 of 27 cases and were detected in 14 (58%) of 24 fetuses on prenatal sonography. Prenatal abnormalities detected by sonography included cyclopia (four of five), ethmocephaly (two of three), cebocephaly (one of three), midline cleft lip (four of eight), lateral cleft lip (two of two), and mild hypotelorism (one of three). One or more extrafacial anomalies were present in 14 (52%) of 27 fetuses. Other major structural anomalies detected prenatally by sonography included meningomyelocele (two of two), renal dysplasia (five of six), omphalocele (three of four), esophageal atresia (zero of three), and cardiac defects (one of seven). Chromosomal analysis revealed abnormal karyotype in 13 (50%) of the 26 fetuses in which it was performed; the most common abnormality was trisomy 13 (seven cases). The perinatal mortality rate was 89% (24 of 27); three neonates with holoprosencephaly were alive when discharged from the hospital. It is concluded that when a major cystic abnormality of the fetal brain is detected, prenatal sonographic analysis of midline facial defect may allow more definitive diagnosis of alobar or semilobar holoprosencephaly; affected fetuses often have other major structural abnormalities, and the outcome is nearly always fatal.

Abnormalities, Multiple↗
PubMed1990

Size of the fetal adrenal in bilateral renal agenesis.

Bilateral renal agenesis is a fetal malformation incompatible with extrauterine life. Accurate prenatal diagnosis is essential for patient counseling. False-negative diagnoses have been reported and were attributed to the sonographic misidentification of apparently hypertrophied fetal adrenal glands as fetal kidneys. To study the relationship between renal agenesis and adrenal size, we reviewed autopsy records from 11 affected fetuses that had undergone careful autopsy and organ weight determination in our laboratory. Anomalies of distant structures were present in five affected fetuses. A sonographic diagnosis of adrenal hypertrophy had been made in two cases. In four of 11 fetuses, the glands had taken on a flattened discoid appearance. The autopsy records of 240 normal fetuses were similarly reviewed, and regression lines were generated for adrenal weight based on foot length and crown-rump length. The adrenal weights from affected fetuses were well within normal limits when compared with these normal regression lines and with organ weight standards from the literature. We conclude that adrenal hypertrophy is not a common finding in this syndrome and that the reported false-negative diagnoses are more likely attributable to a change in adrenal shape rather than a true increase in adrenal mass.

Abnormalities, Multiple↗
PubMed1990

The fetal genitourinary tract.

Early recognition of fetal urinary tract anomalies may dramatically influence obstetric or neonatal management. Major fetal urinary abnormalities, including renal agenesis, obstructive lesions, and cystic disease, may be clinically silent but readily identified by sonography. Careful evaluation of the fetal genitourinary tract should therefore be an important component of the routine screening obstetric sonogram. Appreciation of normal sonographic appearances of the fetal genitourinary tract may facilitate early recognition of the abnormal fetus. Accurate prenatal sonographic characterization of a renal abnormality and evaluation of renal function are essential for fetal prognosis and management.

Constriction, Pathologic↗
PubMed1990

Periventricular echodensities detected by cranial ultrasonography: usefulness in predicting neurodevelopmental outcome in low-birth-weight, preterm infants.

Forty-eight low-birth-weight, preterm graduates of the University of Washington's neonatal intensive care unit who had received periodic, serial scanning by means of cranial ultrasonography during the first 4 to 6 weeks of life were longitudinally observed in an interdisciplinary neurodevelopmental follow-up program to a mean corrected age of 18 months. Mean birth weight for the sample was 1286 g; mean gestational age was 29 weeks. Periventricular echodensities were graded from 0 to 3, with 0 indicating no densities and 3 indicating cystic formation. Intracranial hemorrhage was graded in the conventional manner from 0 to IV. Neurodevelopmental outcome was assessed by means of a neurologic examination and the Bayley Scales of Infant Development. To synthesize the results, neurodevelopmental outcome for each subject was classified as normal, demonstrating minor abnormalities, or demonstrating major abnormalities. Multiple statistical analyses with various subgroupings of subjects consistently indicated severe intracranial hemorrhage (grades III and/or IV) to be a better predictor of overall neurodevelopmental outcome than grade of periventricular echodensity, including small cysts. These results suggest a wide range of outcomes after detection of periventricular echodensities and caution against communicating overly pessimistic prognoses in many cases.

Cerebral Hemorrhage↗
PubMed1989

Long-bone growth in fetuses with Down syndrome.

Short stature is a well-recognized component of Down syndrome. The femur lengths of affected fetuses have been observed to be shorter than normal, with a ratio of actual to expected femur length of less than 0.91 indicating a high risk of trisomy. To further evaluate this finding we have determined the relationship between limb lengths and gestational age in 37 postmortem fetal specimens with trisomy 21. Control values were obtained from 174 normal fetuses. Measurements of the femur, tibia, fibula, humerus, radius, and ulna were made from roentgenograms or by direct measurement of the bone. Most measurements for each bone of the affected fetuses fell below the normal regression line for that bone, but only 3/37 femurs, 4/32 tibias, 5/32 fibulas, 9/32 humeri, 10/32 radii, and 7/32 ulnas fell more than 2 SDs below the mean. The ratios of actual to expected femur lengths were computed and six fetuses with Down syndrome (16.2%) had ratios less than 0.91. The bones of the extremities of fetuses with trisomy 21 are shorter than normal, but the differences are relatively small. The ratio of actual/expected femur lengths was a less efficient predictor of Down syndrome than were either maternal age or maternal serum alpha-fetoprotein tests. The upper extremity bones were shorter than normal more often than were the bones of the lower extremity, and this finding should be explored further in a prospective study.

Bone Development↗
PubMed1989

Disparity of amniotic fluid volume and fetal size: problem of the stuck twin--US studies.

The "stuck twin" phenomenon in monochorionic diamniotic (MCDA) pregnancies is characterized by marked disparity in both fluid volume and fetal size between the twin gestations. To determine the prevalence, sonographic characteristics, and clinical outcome of this phenomenon, discharge summaries, placental pathologic reports, and prenatal sonograms from 307 twin pregnancies were reviewed. Of 52 cases of MCDA pregnancies, 18 (35%) demonstrated marked disparity in amniotic fluid volume. In 16 of these 18 cases there was discordant twin growth, further suggesting the diagnosis of twin transfusion syndrome. All 16 cases and an additional nine cases supplied by another center demonstrated a small, morphologically normal fetus in an oligohydramniotic sac suspended anteriorly (72%) or laterally (28%) in the uterus. The amniotic membrane separating this twin from the larger twin in the polyhydramniotic sac was thin, closely applied to the smaller fetus, and difficult to detect. Perinatal morbidity was 100% for all twin pairs, and premature labor occurred in all cases. Perinatal mortality ranged from 88% for the larger/poly twin to 96% for the small/oligo twin.

Adult↗
PubMed1989

Fetal omphalocele: prenatal US detection of concurrent anomalies and other predictors of outcome.

Forty-six consecutive fetuses with an identified omphalocele were examined with prenatal ultrasound (US) to determine the accuracy of detecting concurrent malformations and to evaluate other possible indicators of fetal outcome. In 43 fetuses with adequate follow-up, 29 (67%) had additional malformations, including 23 with major malformations and six with minor malformations. Thirty-six fetuses (78%) died at termination of pregnancy (n = 23) or spontaneously (n = 13). With the exclusion of pregnancy terminations, fetal mortality was strongly associated with the presence of concurrent malformations, (P less than .001). In 10 surviving fetuses, only three had concurrent malformations, and all were minor. Fetal mortality was also found to be statistically associated with anomalies detected at US (P = .01) and abnormal amniotic fluid volume but was not associated with fetal ascites (P = .64) or omphalocele size (P = .65). Chromosome abnormalities correlated with the absence of liver in the omphalocele sac (P less than .001) and with abnormal amniotic fluid volume (P = .02). Prenatal US can help predict the outcome in fetuses with an omphalocele.

Abnormalities, Multiple↗
PubMed1989

Twin embolization syndrome: prenatal sonographic detection and significance.

Twin embolization syndrome (TES) is a complication of monozygotic twinning following in utero demise of the co-twin. Passage of thromboplastic material into the circulation of the surviving twin results in ischemic structural defects of the central nervous system, gastrointestinal tract, and genitourinary system. In six cases of this rare abnormality, sonographically normal fetuses subsequently demonstrated ventriculomegaly, porencephaly, cerebral atrophy, or microcephaly following demise of the co-twin. Extracranial abnormalities included small bowel atresia (two cases) and renal cortical necrosis (one case). Surviving twins all had neurodevelopmental delay at follow-up. Two fetuses were aborted because of sonographically apparent, progressively severe brain abnormality. The lone survivor of a dizygotic triplet gestation was normal, despite sonographic findings of TES in the co-triplets. Because of poor outcome, prenatal sonographic diagnosis of TES may influence antenatal or neonatal management of the surviving monozygous twin. Recognition of TES may permit accurate postnatal counseling of prognosis and recurrence risks.

Adult↗
PubMed1989

Sonography of placental abnormalities and oligohydramnios in women with elevated alpha-fetoprotein levels: comparison with control subjects.

To evaluate the relationship of placental and amniotic fluid findings to elevated maternal serum alpha-fetoprotein (MS-AFP) levels, we compared sonograms made between 18 and 24 weeks gestational age in 76 women with elevated MS-AFP levels with sonograms of a control group. Patients with fetal malformations, incorrect dates, twins, or lack of follow-up were excluded. Overall, 27 (36%) of 76 patients with elevated MS-AFP levels had placental or amniotic fluid abnormalities compared with only three (3%) of 87 control subjects. Significant differences (p less than .01) were noted in the frequency of periplacental hemorrhage (9% vs 0%), intraplacental sonolucencies greater than or equal to 1.5 cm in diameter (18% vs 3%) and moderate or severe oligohydramnios (17% vs 0%). More patients with elevated MS-AFP levels had placenta previa (4%) or placental thickness greater than or equal to 3.5 cm (12%) than did those in the control group (1% and 5%, respectively), although these differences did not reach statistical significance. Seven (26%) of the 27 patients had more than one abnormality. We conclude that placental and/or amniotic fluid abnormalities are frequently shown on sonograms in women who are examined because of elevated MS-AFP levels.

Amniotic Fluid↗
PubMed1989

Evaluation of normal erectile function with color flow Doppler sonography.

To understand better the vascular events that occur during normal erection, we used color flow Doppler sonography to examine the erectile process in seven normal subjects. The relationship of systolic/diastolic velocities and spectral waveform changes in the penile arteries was studied in response to increasing pressure within the corpora cavernosa (tumescence) before and after the intracorporal administration of drugs to induce erection. A characteristic spectral waveform pattern was identified throughout the erectile cycle, and the pattern was correlated with increasing pressure. Both systolic and diastolic velocities were elevated during the initiation of erection, at which time the pressure within the corpora cavernosa was low (11-25 mm Hg). Systolic velocities remained elevated until the last phase of erection (83-106 mm Hg). Diastolic velocity decreased as the intracorporal pressure increased from 25 to 40 mm Hg. Between 40 and 63 mm Hg, diastolic velocity approximated zero. With increasing pressure (63-83 mm Hg), diastolic flow reversed. As the corpora cavernosa approached full erection (83-105 mm Hg), both the forward systolic and reverse diastolic flow components diminished. At approximately 106 mm Hg (systolic occlusion pressure), flow ceased. Systolic/diastolic velocity and waveform phase relationships could be used to define the integrity of both the cavernosal artery inflow and the venous sinusoidal outflow occlusion mechanisms. Color flow Doppler sonography enhanced our ability to observe and quantify dynamic erectile events and provided new insights into understanding normal erectile function.

Adult↗
PubMed1989

Correlation of intraoperative ultrasound tumor volumes and margins with preoperative computerized tomography scans. An intraoperative method to enhance tumor resection.

Twenty-two patients with primary or metastatic brain tumors were evaluated with computerized tomography (CT) and intraoperative ultrasound. Tumor volume was estimated using a geometric formula based on CT and intraoperative ultrasound measurements. In most cases, tumor margins were marked with indigo carmine injected by ventricular cannula or with Silastic ventricular catheters placed under ultrasonographic control. Nine tumors had previously been operated on and irradiated (Group A). In this group, intraoperative ultrasound tended to overestimate the tumor volume compared to CT (intraoperative ultrasound findings 141.39% +/- 37.73% of CT findings (mean +/- standard deviation]. Sixteen patients were operated on for the first time (Group B), and in this group the volume estimates were comparable (intraoperative ultrasound findings 101.69% +/- 24.65% of CT findings). The difference between the means was statistically significant (p less than 0.01). Ultrasonography improved intraoperative delineation of tumor margins, as depicted by CT, thus maximizing the extent of resection; however, with recurrent tumors, intraoperative ultrasound tended to overestimate the tumor volume. Gliosis may account for this difference.

Adolescent↗
PubMed1989

Chromosomal abnormalities in fetuses with omphalocele. Significance of omphalocele contents.

Twenty-six consecutive fetuses with a sonographically detectable omphalocele and known karyotype were reviewed to identify risk factors that might be associated with chromosomal abnormalities. Risk factors that were analyzed included contents of the omphalocele sac, maternal age, fetal sex, sonographically detectable concurrent anomalies, and any major concurrent anomaly. Chromosomal abnormalities were found in 10 cases (38%) from trisomy 18 (n = 4), trisomy 13 (n = 4), trisomy 21 (n = 1), or 45, X (n = 1). The absence of liver from the omphalocele sac (intracorporeal liver) was strongly associated with an abnormal karyotype; chromosomal abnormalities were present in all 8 fetuses with an intracorporeal liver compared to 2 of 18 fetuses with an extracorporeal liver (p less than .0001, two-tailed Fisher exact test). Other risk factors that were statistically associated with chromosomal abnormalities included advanced maternal age (greater than or equal to 33 years, p = .03) and sonographically detectable concurrent malformations (p = .05). We conclude that sonographic findings can help determine the relative risk of chromosomal abnormalities in fetuses with omphalocele; abnormal karyotypes were significantly associated with the absence of liver from the omphalocele sac and sonographically detectable concurrent malformations in this series. Sonographers should also be aware that omphaloceles that contain bowel alone tend to be small and can be missed or mistaken for other abdominal wall defects (gastroschisis or umbilical hernia).

Adolescent↗
PubMed1989

Choroid plexus cysts in fetuses with trisomy 18.

An association between fetal choroid plexus cysts and trisomy 18 has been suggested. However, the prevalence of such cysts in aneuploid fetuses is unknown. To determine this frequency, we studied 14 fetuses with trisomy 18 examined at the Central Laboratory for Human Embryology. Five fetuses were found to have choroid plexus cysts on postmortem ultrasound examination. All those with cysts were earlier than 26 weeks in gestation, and the prevalence among second-trimester fetuses was 71.4%. In contrast, such cysts are reported in less than 1% of the general population of second-trimester fetuses. Thus, choroid plexus cysts are common in trisomy 18, and the finding of such cysts on a second-trimester ultrasound examination should suggest further evaluation, including chromosome analysis.

Choroid Plexus↗
PubMed1988

Tibialis posterior tendon rupture: a cause of rheumatoid flat foot.

Flat foot, a major cause of foot pain and disability, may result from rupture of the tibialis posterior tendon. We describe 2 patients with rheumatoid arthritis who developed flat feet secondary to surgically confirmed tendon rupture, and we discuss the anatomy and diagnosis of this condition. In the second patient, we also present the results of tendon imaging with both magnetic resonance and ultrasound.

Aged↗
PubMed1988

Scrotal ultrasonography: a predictor of complicated epididymitis requiring orchiectomy.

The decision between continued medical therapy and surgical exploration in patients with complicated epididymitis is difficult. We evaluated scrotal ultrasonography as a noninvasive aid in such problematic cases. During a 48-month period 95 patients were hospitalized for treatment of epididymitis; 23 underwent scrotal ultrasonography and 10 required orchiectomy. Analysis of the 21 cases with abnormal findings demonstrated that orchiectomy was necessary in 1 of the 10 patients (10 per cent) with epididymal enlargement only, in 2 of 8 (25 per cent) with epididymal enlargement plus hypoechoic testes and in all 3 with epididymal enlargement plus testicular inhomogeneity (p equals 0.0099). Patients with progressive testicular changes on serial ultrasound examinations uniformly required orchiectomy (5 of 5). Sonographic findings of testicular inhomogeneity correlated with testicular infarction and findings of decreased testicular echogeneity correlated with acute or chronic orchitis. In the appropriate clinical setting gray scale ultrasonography provides objective information supporting the need for surgical intervention in selected patients with complicated epididymitis.

Epididymitis↗