The "lemon" sign: a clinical perspective.
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Female↗
Biomedical subjects
R A Filly
Publications and source records attributed to R A Filly.
Imaging the testis: comparison between MR imaging and US.
The potential role of magnetic resonance (MR) imaging in the diagnosis and local staging of testicular tumors was evaluated in 23 patients who subsequently underwent surgery or biopsy. Findings at MR imaging were compared with those at ultrasonography (US) and were correlated with the surgical-histologic findings. At surgery, three patients were found to have extratesticular and 20 patients intratesticular abnormalities. This distinction had been correctly made with both imaging modalities, but US did not demonstrate the intratesticular abnormality in four patients with diffuse infiltrating tumors. Neither modality allowed differentiation of benign from malignant disorders. When local tumor staging was analyzed in 11 patients, the accuracy of both modalities was disappointing (true-positive findings with MR imaging in seven patients and with US in five). At present, US remains the primary imaging modality for testicular disease. MR imaging should be employed when findings at physical examination and US are discrepant and considered when diffuse infiltrative disease is suspected.
Humans↗
Exclusion of fetal ventriculomegaly with a single measurement: the width of the lateral ventricular atrium.
The ventricular atria in 100 healthy fetuses with gestational ages ranging from 14 to 38 menstrual weeks were evaluated and compared with those of 38 fetuses in whom ventriculomegaly had been diagnosed in utero. Axial sonograms of the brain through the atrium of the lateral ventricle demonstrated that the normal atrial diameter remained relatively constant throughout the gestational age range observed. The atrium had a mean diameter of 7.6 +/- 0.6 mm (standard deviation [SD]). Measurement of this structure can be quickly performed, is reproducible with low intra- and interobserver variation, and permits ventriculomegaly to be excluded. Atrial diameters exceeding 10 mm (above 4 SDs) suggest ventriculomegaly, with a low false-positive rate.
Brain↗
Prenatal diagnosis of anencephaly: spectrum of sonographic appearances and distinction from the amniotic band syndrome.
To document the characteristic sonographic abnormalities of anencephaly and to identify potentially confusing sonographic features, we reviewed 20 cases of anencephaly. All of these cases were diagnosed prenatally with sonography after 14 menstrual weeks in patients who were seen at our institution between 1984 and 1988. In all cases, the correct diagnosis was made on the prenatal sonograms and was confirmed pathologically. The sonographic diagnosis was primarily based on the absence of brain and calvarium superior to the orbits on coronal views of the fetal head. This typical appearance was altered by the presence of echogenic tissue superior to the orbits in nine (45%) of 20 cases. Pathologically, the tissue corresponded to angiomatous stroma (area cerebrovasculosa) and appeared quite sizable on sonograms in four fetuses (20%). It may appear solid or mixed solid and cystic. In one fetus, it appeared brainlike. Despite this appearance, the sonologist should not be dissuaded from the diagnosis of classic anencephaly. Hydramnios occurred in seven (35%) of 20 patients, and oligohydramnios occurred in none of the patients. Anencephaly may be distinguished from the cranial defects associated with the amniotic band syndrome (amputation defects that occur as the sequelae of amniotic disruption) on the basis of the symmetry of the cranial defects (100% of anencephalic fetuses in this series) and the absence of limb, body wall, and spinal abnormalities that typically accompany the amniotic band syndrome. Although there may be minor variations in the sonographic appearance of the cranial defect of anencephalic fetuses (i.e., much or little angiomatous stroma), we conclude that this anomaly can be accurately detected and diagnosed on fetal sonograms obtained after 14 weeks menstrual age and distinguished from the amniotic band syndrome.
Amniotic Band Syndrome↗
The dangling choroid plexus: a sonographic observation of value in excluding ventriculomegaly.
To show that the position of the choroid plexus is dependent on gravity and to prove that this fact can be used as a simple means of avoiding the erroneous diagnosis of ventriculomegaly on fetal sonography, we evaluated 75 fetal sonograms retrospectively. Twenty-five fetuses had ventriculomegaly, and 50 had normal cerebral ventricles. The gestational ages ranged from 15 to 39 weeks. To show objectively that the position of the choroid plexus within the lateral ventricle was gravity dependent, we measured the choroid angle in each case. The choroid angle (the angle between the long axis of the choroid plexus and the linear midline echo on transverse axial sonograms through the body of the lateral ventricles) varied directly with ventricular size. In the group with normal-sized ventricles, the values for choroid angle followed a normal, unimodal distribution and had a mean of 14 degrees, a range of 6-22 degrees, and an SD of 4.3 degrees. In cases of ventriculomegaly, the values for choroid angle did not follow a normal distribution and ranged from 29 to 90 degrees. The choroid "dangled" from its attachment at the foramen of Monro and rested on the dependent wall of the lateral ventricle, resulting in a choroid angle that was increased over normal; the degree of the angle was dependent on the severity of the ventricular enlargement. The resting position of the choroid plexus marked the position of the lateral ventricular wall even when the reflection of ultrasound from the ventricular wall itself could not be seen. Detection of the position of the dependent choroid plexus is a simple observation that can be used to avoid the erroneous diagnosis of fetal ventriculomegaly and to help gauge the severity of true ventricular enlargement.
Cerebral Ventricles↗
Sonography of nonconjoined monoamniotic twin pregnancies.
Five nonconjoined monoamniotic twin pregnancies were identified prenatally by sonography. In all cases the diagnosis was made when umbilical cords of the two fetuses were seen to be entangled. One monoamniotic twin pregnancy was not recognized prenatally because the cords were not seen to be entangled. Although monoamniotic twins frequently die related to cord knotting, sonographic visualization of cord entanglement does not imply impending demise. Visualization of cord entanglement appears to be specific for the diagnosis of monoamnionicity, but the sensitivity is not known. Prenatal diagnosis allows informed planning of obstetrical monitoring and mode of delivery.
Female↗
Factors affecting prenatal sonographic estimation of weight in extremely low birthweight infants.
Because critical management decisions are based on sonographic estimation of fetal weight in fetuses less than 1000 g, we sought to evaluate the accuracy of birthweight prediction in this range and to identify factors affecting this accuracy. Fetal weight was estimated using several published methods in 53 fetuses with birthweights less than 1000 g. Standard deviations greater than 12.3% indicate more random error in the sonographic weight prediction than has been reported in higher weight groups. No statistically significant differences were found between patient groups with decreased, normal, or increased amniotic fluid volume or portable examination. There was a trend toward lower mean deviation (2.9 vs 6.0%) and standard deviation (8.9 vs. 15.0%) in studies with scan quality judged "good" compared with "poor" based on ability to visualize anatomic landmarks.
Amniotic Fluid↗
Membrane thickness in ultrasound prediction of chorionicity of twin gestations.
A retrospective review of sonograms performed on 75 twin gestations was performed to evaluate the ability of sonography to distinguish monochorionic from dichorionic gestations based on the thickness of the membrane separating the fetuses. Clinical or pathologic evidence of chorionicity and amnionicity was available in all cases. A thick membrane had a predictive value of 83% for dichorionicity and was seen in 89% of the first sonograms obtained on dichorionic gestations. Of third trimester dichorionic pregnancies, a thick membrane was seen in only 52%. A thin membrane on the initial study had a predictive value for monochorionic diamniotic pregnancy of 83%, but was seen in only 54% of cases. There was 100% intraobserver and 91% interobserver concordance in interpretation of membrane thickness. Technical factors important in interpretation of membrane thickness are discussed. The appearance of the membrane can be useful in sonographic evaluation of chorionicity and amnionicity in twin gestations, but should be used in conjunction with all other information available.
Amnion↗
Sonographic estimation of amniotic fluid volume. Subjective assessment versus pocket measurements.
Amniotic fluid volume (AFV) estimation is an important part of routine obstetric sonography. Despite the clinical importance placed upon excessive or diminished AFV in pregnancy, there is little uniformity in the way it is estimated sonographically. We compared AFV estimations obtained using two commonly employed sonographic methods "subjective" visual assessment and amniotic fluid pocket measurements. Estimates obtained using both methods correlated closely. In addition, there was excellent intraobserver and interobserver agreement among estimates obtained using subjective criteria. This supports the belief that experienced observers tend to agree on the sonographic appearance of normal, excessive or decreased AFV. Methods for AFV estimation and potential pitfalls are discussed.
Amniotic Fluid↗
Sonographic identification of autosomal recessive polycystic kidney disease associated with increased maternal serum/amniotic fluid alpha-fetoprotein.
A patient with no family history of renal disease was referred for obstetric sonography because of elevated maternal serum and amniotic fluid alpha-fetoprotein (AFP), and was proved to be carrying a fetus with autosomal recessive polycystic kidney disease. Review of records of previous cases with a sonographic diagnosis of this disease revealed one other case with elevated and one case with normal amniotic fluid AFP. Sonographers should be aware of the potential diagnosis of this condition in patients with elevated AFP, even in gestations not known to be at risk. Because the sonographic diagnosis of this disease can be difficult in gestations known to be at risk, AFP determination may prove to be a useful diagnostic adjunct in these pregnancies as well.
Adult↗
Natural history of fetal ventriculomegaly.
The natural history of in utero ventriculomegaly was defined by a retrospective review of the outcome of 47 fetuses evaluated during a 5-year period by the Fetal Treatment Program at the University of California. In 20 fetuses, a diagnosis of ventriculomegaly associated with other severe abnormalities was made early in pregnancy. Termination of pregnancy was elected in 19 of 20 cases, and no fetus survived. In five fetuses, the diagnosis was made late in pregnancy and was associated with severe abnormalities. Fetuses were handled in a routine obstetric fashion and none survived. Of the other 22 fetuses 19 had stable and two had progressive ventriculomegaly; in one case, ventriculomegaly resolved in utero. Nineteen of these fetuses have survived, 13 with normal intellectual development and six with moderately to severely delayed development. Associated abnormalities were detected with ultrasonography in 74% of fetuses; there was a 20% false-negative rate of detection. Ventriculomegaly was isolated and progressive in two fetuses. In both cases, fetuses were delivered at term, and postnatally a shunting procedure was performed. Both children are neurologically normal. From our results and a review of the literature, which supports our findings, we were unable to define a group of fetuses with in utero ventriculomegaly that would benefit from in utero shunting.
Abortion, Therapeutic↗
Ultrasonically evident fetal nuchal skin thickening: is it specific for Down syndrome?
Fetal nuchal thickening in the second trimester is suggested as an ultrasonographic sign strongly suggesting the presence of Down syndrome. To better understand this potentially valuable observation, we explored aspects of the finding not considered in previous reports. The published data were reanalyzed to estimate statistically the presence of the sign in a low-risk obstetric population. Second, films of chromosomally normal fetuses were reviewed to confirm the normal range of measurement. Finally, autopsy reports of aborted Down syndrome fetuses were reviewed. Our results confirm that true nuchal thickening is present in some second-trimester Down syndrome fetuses. Unfortunately, a positive sign occurs in a significant proportion of chromosomally normal fetuses. Also our calculations predict a high incidence of false positive results in a low-risk obstetric population. Consequently we urge caution in the interpretation of these findings until prospective characterization of these observations is available.
Down Syndrome↗
Fetal hydronephrosis: selection and surgical repair.
Newly developed diagnostic techniques allowed us to select a fetus with potentially reversible renal damage from the usually fatal group with bilateral hydronephrosis and severe oligohydramnios early in gestation. Fetal surgery to marsupialize the fetal bladder at 24 weeks gestation restored normal amniotic fluid dynamics and allowed sufficient pulmonary and renal development to insure survival after delivery near term.
Adult↗
Ectopic pregnancy: the role of sonography.
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Chorionic Gonadotropin↗
Posttransplant renal rejection: comparison of quantitative scintigraphy, US, and MR imaging.
Accuracy of ultrasonography (US), quantitative scintigraphy, and magnetic resonance (MR) imaging in diagnosis of acute renal allograft rejection was studied in 46 patients who underwent renal biopsy. Thirty-three patients had acute rejection; six, cyclosporine nephrotoxicity, as shown by biopsy, clinical findings, and follow-up study; two, acute tubular necrosis; and five, normal biopsy findings and renal function. Accuracy in demonstrating rejection was 72% for US and 75% for scintigraphy, indicating no significant difference between the two. MR imaging was significantly more accurate, reaching a level of 98%. However, accuracy of MR in demonstrating acute tubular necrosis in a larger number of patients is not known, and its accuracy in indicating recurrent glomerulopathy or infectious disease has not been addressed. The definitive role of MR in evaluating posttransplant renal failure is currently not established, but because of its high sensitivity in detecting renal abnormality, MR can be used for cases when results of US or scintigraphy are equivocal or contradict clinical impressions or when biopsy cannot be performed for medical reasons.
Adult↗
Gastroschisis: prenatal diagnosis and management.
Ten fetuses with gastroschisis on whom a prenatal sonographic diagnosis and evaluation were available and who delivered at the University of California, San Francisco, were evaluated retrospectively. Six fetuses were delivered vaginally without mortality and minimal or absent morbidity. Four were delivered abdominally, 2 for unrelated obstetrical indications. A 3rd fetus had a suspected prenatal bowel perforation and was the sole mortality. Only 1 mother underwent primary cesarean section, specifically due to the fetal gastroschisis. Umbilical cord pH values were normal in those delivered vaginally. With careful ultrasound examination and immediate neonatal surgical capability in a level III perinatal center, vaginal delivery of fetuses with gastroschisis can be associated with excellent outcome. A multinational randomized study of the delivery mode of fetuses with gastroschisis is necessary and appropriate at this time.
Abdominal Muscles↗
Perinatal management of the fetus with an abdominal wall defect.
The antenatal diagnosis of abdominal wall defects has allowed improved perinatal management. For fetuses with associated anomalies, the options of elective termination or minimal intervention can be offered. Our ability to predict the extent of bowel damage in gastroschisis based on the ultrasound findings enables us to offer early delivery to those fetuses who are at high risk. The data are not clear at the present time whether cesarean section offers any advantage. These fetuses should, however, be delivered at a center which is capable of providing high level medical and surgical care to these potentially ill infants. Initial resuscitation of these neonates requires early insertion of an intravenous line and a nasogastric tube, the administration of antibiotics, sterile coverage of the eviscerated bowel, and careful attention to temperature instability. Neonates with gastroschisis should be operated on as soon as they are stable, whereas infants with omphalocele can be investigated for associated anomalies prior to surgery. Primary fascial closure is performed whenever possible. Where this is not possible, a staged repair using a silastic chimney achieves closure within 3-6 days. Skin coverage alone or nonoperative management is reserved for the few cases with giant omphalocele, associated anomalies, or poor operative risk. Decisions about primary versus delayed closure, while usually dictated by clinical judgement, can be aided by indirect measurement of intraabdominal pressure. Postoperative ventilation, and consideration of long-term nutritional needs, are also important parts of the perioperative management.
Abdominal Muscles↗
Sonography in the diagnosis of acute renal allograft rejection and cyclosporine nephrotoxicity.
High-resolution real-time sonography was used at the time an allograft biopsy was performed on 58 renal transplant recipients to elucidate the cause of posttransplantation decline in renal function. These procedures were performed within 3 months of transplantation. Fifty-four out of 58 patients were on a cyclosporine-steroid regimen. Acute rejection was diagnosed if one or more of the following findings was present on sonogram: transplant swelling, increased conspicuity of the medullary pyramids, medullary pyramid enlargement, decreased renal-sinus fat, and pelvi-infundibular thickening. Correlation of sonography and histopathologic findings showed that sonography cannot be used independently to diagnose rejection or to distinguish between cyclosporine nephrotoxicity and rejection. A creatinine level of 2.5 mg/dl was then randomly selected as a threshold level to possibly improve the sonographic results, anticipating that above this threshold an abnormal sonogram would invariably be recorded in the presence of rejection. This threshold was not found to be discriminatory. Only at a higher threshold level of creatinine (6.9 mg/dl or more) was there 100% correlation between acute rejection and the presence of abnormal sonographic findings. Furthermore, whereas most patients with four or five abnormal sonographic criteria tended to have acute rejection, this group of patients constituted a minority and, even within this group, sonography was not entirely reliable in detecting transplant rejection.
Cyclosporins↗