Search PubMed⌕ Search

Biomedical subjects

L A Mack

Publications and source records attributed to L A Mack.

At least 91 records · Page 5Linked to original sources
PubMed1987

Fetal hydrocephalus: sonographic detection and clinical significance of associated anomalies.

Sixty-one cases of fetal hydrocephalus were reviewed to determine the accuracy and clinical significance of prenatal ultrasound (US) for detecting concurrent anomalies. Of 61 fetuses studied, 51 (84%) had one or more major central nervous system (CNS) malformations (38 fetuses with 39 anomalies) and/or extra-CNS anomalies (34 fetuses). Only ten (16%) fetuses had no concurrent anomaly. Anomalies of the CNS were correctly identified with US in 35 of 39 (90%) cases. Of 34 fetuses (56%) with extra-CNS anomalies, 27 had multiple anomalies. One or more extra-CNS abnormality was identified with US in 22 of the 27 (81%) fetuses with multiple anomalies but no anomalies were identified with US in the seven patients with an isolated anomaly. Fetal mortality was directly related to the presence of extra-CNS anomalies (P less than .01). Many important anomalies coexisting with fetal hydrocephalus can be identified with US. Furthermore, sonographic detection of extra-CNS malformations carries a poor prognosis and was associated with a uniformly fatal outcome in this series.

Abnormalities, Multiple↗
PubMed1987

Placental abruption and placental hemorrhage: correlation of sonographic findings with fetal outcome.

Sixty-nine cases of placental abruption and placental hemorrhage detected with ultrasonography (US) were reviewed retrospectively to determine whether US findings correlate with fetal outcome. Four patients were lost to follow-up, and in the remaining 65 patients fetal outcome included demise in 12 cases (18%), termination of pregnancy in six (9%), premature delivery of a living infant in 15 (23%), term delivery of an infant who was small for gestational age in four (6%), and normal term delivery in 28 (43%). Fetal mortality correlated best with the estimated percentage of placental detachment, but was also significantly (P less than .01) associated with the location (retroplacental) and size (greater than 60 ml) of hemorrhage. Premature labor was associated (P less than .001) only with gestational age at the time of clinical presentation. No sonographic finding was identified as a risk factor for small-for-gestational-age infants. Sonographic findings of placental abruption correlate with fetal outcome, and this information may be useful for guiding obstetric management.

Abruptio Placentae↗
PubMed1987

Meconium peritonitis: prenatal sonographic findings and their clinical significance.

Ultrasonographic (US) findings were correlated with clinical outcome in seven cases of meconium peritonitis detected with prenatal US during a 2-year period. Nineteen previously reported cases were also reviewed. US findings included intraabdominal calcifications (n = six cases), fetal ascites (n = 3), echogenic ascites without calcifications (n = 1), bowel dilatation (n = 2), and polyhydramnios (n = 5). Following delivery, six infants were still alive after a mean follow-up of 13 months (range, 6-26 months); the seventh died of hydrocephalus. Of the six, four required surgical correction of a small-bowel perforation and two did not. All six are thriving, and none has yet been found to have cystic fibrosis. In the 19 previously reported cases, there were only two cases of cystic fibrosis, neither with intraabdominal calcifications. The presence of calcifications was significantly associated with causes other than cystic fibrosis. Prenatally diagnosed cases of meconium peritonitis are associated with cystic fibrosis less frequently than previous studies suggest.

Ascites↗
PubMed1987

Colorectal neoplasms: accuracy of US in demonstrating the depth of invasion.

Six normal and 16 neoplastic colorectal specimens were examined with 8.5-MHz ultrasound (US). An articulated system facilitated precise spatial correlation between US and histologic sections. Images were blindly interpreted and then compared with histologic results. All six normal specimen showed five distinct echo layers and were distinguished from neoplastic specimens by all the observers. The central echogenic layer, corresponding to the submucosa, is useful in determining the depth of origin of a neoplasm and the presence of submucosal invasion. US had an accuracy of 92.5% in demonstrating invasion of the submucosa and 77% for invasion of the muscularis externa. For mucosal neoplasms with invasion through the muscularis externa and extension into the subserosal tissues, nearly 90% of US interpretations were correct. High-frequency US may be useful in determining the depth of invasion of mucosal tumors with respect to the submucosa and in differentiating mucosal from extramural masses.

Biopsy↗
PubMed1987

Sonographic spectrum of placental abruption.

Fifty-seven cases of placental abruption detected by sonography were retrospectively reviewed. The location of hemorrhage was subchorionic in 46 cases (81%), retroplacental in nine cases (16%), and preplacental in two cases (4%). Subchorionic hematomas were more frequently shown in the 33 patients presenting before 20 menstrual weeks (91%) than in the 24 patients presenting after 20 weeks (67%). The echogenicity of hemorrhage depended on the time the sonogram was performed relative to the onset of symptoms: Acute hemorrhage was hyperechoic to isoechoic compared with the placenta, while resolving hematomas became hypoechoic within 1 week and sonolucent within 2 weeks. Acute hemorrhage was occasionally difficult to distinguish from the adjacent placenta. This occurred in five retroplacental hematomas that showed only an abnormally thick and heterogeneous placenta. Nine cases of placental abruption were initially confused with other mass lesions. Placental abruption causes a wide spectrum of sonographic findings that may be overlooked or misdiagnosed.

Abruptio Placentae↗
PubMed1987

Anorectal atresia: prenatal sonographic diagnosis.

To determine the prenatal sonographic findings of anorectal atresia (ARA), we retrospectively reviewed 12 proven cases. Sonography showed abnormally dilated bowel segments in five cases (42%), four of which were identified prospectively; at autopsy, two other cases showed mild colon dilatation not evident on sonograms. Bowel dilatation was not associated with the location of atresia or the presence of a fistula, but was possibly related to menstrual age. Eleven fetuses (92%) had significant other anomalies primarily related to the VACTERL syndrome (vertebral defects, anal atresia, tracheoesophageal fistula with esophageal atresia, radial and renal dysplasia, and limb malformations) and/or the caudal regression syndrome; of these, sonography identified one or more concurrent anomalies in seven cases. In two cases, bowel dilatation was the primary sonographic finding. Death in nine cases resulted from termination of pregnancy (four cases) or perinatal demise (five cases); three patients are still alive. We conclude that some cases of ARA can be suspected on prenatal sonograms by demonstration of dilated colon, and that the sensitivity of this finding may be related to menstrual age at the time of the examination. Distinguishing ARA from other causes of fetal-bowel dilatation is important because of the frequency of concurrent anomalies associated with ARA.

Abnormalities, Multiple↗
PubMed1987

Sonography in the detection of meniscal injuries of the knee: evaluation in cadavers.

We evaluated the ability of high-resolution, real-time sonography to identify and characterize artificially produced lesions in the menisci in human cadaveric knee specimens. In total, 20 lesions created in 10 specimens from five knees were prepared and examined sonographically. Four different types of lesions were created: eight vertical concentric tears, four horizontal tears, four vertical radial tears, and four complex lesions including displaced or amputated meniscal edges. All 20 (100%) of the lesions were visualized sonographically. The vertical concentric tears were the easiest to locate and identify, and appeared as highly echogenic lines in the menisci. Tears of this type as small as 2 mm could be visualized. The vertical radial tears were the most difficult to visualize, and no lesions of this type smaller than 5 mm could be seen. Our study shows that under optimal experimental conditions, sonography is capable of reliably demonstrating even small meniscal tears. On this basis, we believe that further clinical studies of the efficacy of meniscal sonography are both reasonable and necessary.

Cadaver↗
PubMed1987

Holoprosencephaly: prenatal sonographic diagnosis.

Fourteen cases of holoprosencephaly (HP), including 10 cases of alobar HP and four cases of semilobar HP, were identified by prenatal sonography. Intracranial and extracranial findings were reviewed to determine the accuracy and spectrum of the sonographic features. All 14 cases were reliably distinguished from other causes of fetal hydrocephalus (n = 58) detected during the same period by demonstrating absence of the midline echo (falx cerebri and interhemispheric fissure), fusion of the thalami, and abnormal ventricular configuration. Four cases of semilobar HP demonstrated incomplete fusion of the thalami and partial separation of the ventricles compared with alobar HP. Eight cases demonstrated a dorsal cyst including five with alobar HP and three with semilobar HP. One case demonstrated an unusual extraaxial fluid collection surrounding the brain, thought to be from rupture of a dorsal cyst. Facial features that were identified included a proboscis (three cases), midline facial cleft (three cases), and hypotelorism (five cases). Extracranial abnormalities that were identified included polydactyly (two cases), renal dysplasia (two cases), omphalocele (one case), and fetal hydrops (one case). We conclude that fetuses with HP can exhibit a spectrum of sonographic findings and that alobar or semilobar HP is reliably distinguished from other causes of fetal hydrocephalus by distinctive intracranial findings.

Abnormalities, Multiple↗
PubMed1987

Endovaginal sonographic evaluation of ectopic pregnancy: a prospective study.

To determine the value of endovaginal sonography for evaluating women with a suspected ectopic gestation, we prospectively studied a group of 84 pregnant women in whom conventional transabdominal sonograms failed to show a living embryo. Of 84 patients studied, 25 had an ectopic gestation, 32 had a normal intrauterine pregnancy, and 27 had an abnormal (nonviable) intrauterine pregnancy. Endovaginal sonography, compared with transabdominal sonography, provided additional information in 50 cases (60%) and less information in only three cases (4%). Of 25 ectopic gestations, endovaginal sonography provided new information in 15 cases (60%) including detection of an extrauterine gestational sac (10 cases), extrauterine embryo (two cases), or adnexal mass (three cases) not observed on transabdominal sonography. Of 32 normal intrauterine pregnancies, endovaginal sonography provided additional information in 26 cases (81%) including detection of a yolk sac (14 cases), living embryo (11 cases), or small gestational sac (one case) not seen on transabdominal sonography. Of 27 abnormal intrauterine pregnancies, endovaginal sonography showed additional information in nine cases (33%) including detection of embryonic demise (three cases), retained intrauterine products (four cases), or a yolk sac (two cases) not seen on transabdominal sonography. Patient acceptance of endovaginal sonography was excellent; 82% of the patients preferred this method to transabdominal sonography, 13% expressed no preference, and 5% preferred transabdominal sonography. We conclude that endovaginal sonography can provide significant additional information in the majority of women who are referred for sonography with a suspected ectopic gestation. We believe that this method should become a integral part of sonographic evaluation in women who are suspected of having an ectopic gestation when conventional transabdominal sonography fails to show a living embryo.

False Positive Reactions↗
PubMed1987

Distinguishing normal from abnormal gestational sac growth in early pregnancy.

In order to evaluate normal and abnormal gestational sac development, serial sonograms were performed in 83 women whose initial sonogram demonstrated a gestational sac lacking a detectable embryo. Of 53 normal gestations, the mean sac growth was 1.13 mm/day (range, 0.71-1.75). In comparison, of 30 abnormal gestations, 24 demonstrated sac growth, and of these, the mean growth was 0.70 mm/day (range, 0.14-1.71). Based on these observations, we suggest that gestational sac growth of less than or equal to 0.6 mm/day is evidence for abnormal development. Analysis of the initial and follow-up scans for the 53 normal gestations showed that a living embryo was always detected when the mean gestational sac was greater than 25 mm in average diameter, and a yolk sac was always seen when the mean sac diameter was greater than 20 mm. In comparison, of 30 abnormal gestations, six were greater than 25 mm without a detectable embryo, and four were greater than 20 mm without a yolk sac. Recommendations for the optimal time of a follow-up sonogram are presented based on the initial sac size.

Embryo Loss↗
PubMed1987

Fetal bowel. Normal sonographic findings.

The normal sonographic appearance of fetal colon and small bowel is reported in a prospective study of 130 fetuses. The colon, which appeared as a continuous tubular structure located around the perimeter of the abdominal cavity, was seen in some fetuses as early as 22 menstrual weeks and in all fetuses examined after 28 weeks. Colon diameter demonstrated a linear relation (r = 0.82) with menstrual age, reaching a maximum of 18 mm at term. In comparison, small bowel was located centrally and individual segments never exceeded 7 mm in diameter or 15 mm in length. Small bowel loops were seen in only 30% of fetuses examined after 34 weeks. Peristalsis was routinely demonstrated of the small bowel, but was not observed in the colon.

Colon↗
PubMed1987

Ectopic pregnancy. Diagnosis by sonography correlated with quantitative HCG levels.

Pelvic sonograms were correlated with simultaneous human chorionic gonadotropin (HCG) determinations in 150 women with early intrauterine pregnancy (N = 76) and ectopic pregnancy (N = 74). Of the 76 patients with intrauterine pregnancy (IUP), 55 had HCG levels exceeding 1,800 mIU/ml (Second International Standard), and in each case a gestational sac was identified. In comparison, 35 of 74 (47%) patients with ectopic pregnancy had HCG levels of 1,800 mIU/ml or more, and no case demonstrated a gestational sac. Although six patients (8%) with ectopic pregnancy demonstrated a "pseudogestational sac," no case was confused with a true gestational sac. We conclude that, when the HCG level exceeds 1,800 mIU/ml, an intrauterine gestational sac is normally detected and its absence is evidence for an ectopic pregnancy.

Chorionic Gonadotropin↗
PubMed1986

High resolution sonography of the menisci of the knee.

High-resolution real-time ultrasonography (5, 7.5, and 10 MHz) was used to examine the menisci of the knee in ten normal volunteers and in ten patients with knee injuries. The posterior horns of the medial and lateral menisci were easily demonstrated. Normal anatomy and pathologic changes could be imaged in the menisci, capsular ligaments, and articular cartilage. While the menisci were seen in all subjects, the weight-bearing portion of the femoral articular cartilage could not be seen in several of the symptomatic patients who could not flex their knees. Ultrasound promises to be a useful, noninvasive adjunct to conventional techniques in evaluating the injured knee--especially in assessing the posterior horns of the menisci, an area difficult to assess with arthroscopy.

Humans↗
PubMed1986

Pancreatic insufficiency: role of CT evaluation.

The medical records of all patients discharged over a 3-year period with a diagnosis of pancreatic insufficiency were reviewed. In some patients, abdominal radiographs or sonograms provided adequate information. However, computed tomography (CT) was a key diagnostic tool in understanding the cause of pancreatic insufficiency in 11 of the 13 patients in whom it was performed. CT study detected previously undiagnosed carcinoma in one patient, enabled diagnosis of chronic pancreatitis in five, confirmed complete surgical removal of the pancreas in two, and--despite optimal use of contrast material and 5-mm contiguous sections--was unable to detect any pancreatic tissue in three patients, suggesting complete idiopathic atrophy. Pancreatic insufficiency is a difficult clinical diagnostic problem. CT scanning should be employed early if abdominal radiographs or sonograms do not detect an abnormality.

Adult↗
PubMed1986

Intraoperative US as an aid to intraoperative electron beam radiation therapy.

Intraoperative electron-beam radiation therapy (IRT) is being used to treat certain abdominal malignancies. Accurate determination of tumor size, depth, and extent is necessary to select a treatment cone of appropriate size and appropriate electron beam energy for the treatment portal. Fourteen patients undergoing evaluation for this treatment were examined with intraoperative ultrasonography (IUS) to aid therapy planning. IUS study required little additional time and readily delineated tumor size, depth, and relationship to adjacent structures. In two patients, the US and operative findings provided information that precluded use of IRT. The traditional method of tumor evaluation by intraoperative palpation and inspection was consistently enhanced by the use of IUS findings. IUS is a valuable adjunct that improves the accuracy of therapy planning for IRT.

Abdominal Neoplasms↗
PubMed1986

Bowel migration in the normal fetus: US detection.

Ten fetuses underwent ultrasound scanning at 7-10 weeks gestational (postmenstrual) age. In all cases, an echogenic mass measuring 0.5-1.0 cm was demonstrated within the base of the umbilical cord at its insertion into the fetal abdomen. No area with echogenicity characteristic of the small bowel was identified within the lower part of the fetal abdomen. All fetuses were reexamined 4-12 weeks later, at which time the mass in the umbilical cord was no longer seen, and normal fetal bowel was visualized in the lower abdominal cavity of the fetus. This sequence of findings appears to represent the sonographic demonstration of normal fetal bowel migration early in gestation and should not be confused with defects of the abdominal wall such as omphalocele or gastroschisis.

Abdominal Muscles↗
PubMed1986

Changing appearance of the normal uterus during the menstrual cycle: MR studies.

The authors obtained sagittal magnetic resonance (MR) images twice a week from six healthy women during one full menstrual cycle to establish the changes depicted in the uterine layers. Parallel endocrine and ultrasound studies were used to establish the day of ovulation precisely. Consistent changes in the thickness and intensity of the endometrium and myometrium wer noted in all subjects during the menstrual cycle. Both myometrial thickness and endometrial area increased linearly during the follicular (preovulatory) phase of the cycle; the rate of increase dropped significantly during the luteal phase. Two myometrial layers were observed; the best contrast between the layers was demonstrated during the first half of the cycle.

Adult↗