Nonstenotic internal carotid arteries: effects of age and blood pressure at the time of scanning on Doppler US velocity measurements

PURPOSE

To assess the effects of age and blood pressure at the time of scanning on internal carotid artery velocities and cross-sectional diameter at Doppler ultrasonography (US).

MATERIALS AND METHODS

During 12 months, 1,020 consecutive patients underwent internal carotid artery Doppler US. No or minimal arterial disease was found in 142 patients (67 women, 75 men). Blood pressure was recorded prior to examination. The angle-corrected internal carotid artery peak systolic and end-diastolic velocities were obtained. The effects of systolic blood pressure, diastolic blood pressure, pulse pressure, age, chronic hypertension, and medications for hypertension on velocities were evaluated by using linear regression analysis.

RESULTS

Peak systolic velocity was influenced by age (P =.008), systolic blood pressure (P =.009), diastolic blood pressure (P =.003), and pulse pressure (P =.017) but not history of hypertension (P =.53) or antihypertensive medication use (P =.77). Increasing age decreased peak systolic velocity by 0.34 cm/sec/y. End-diastolic velocity was influenced by age (P <.001) but not by systolic, diastolic, or pulse pressure (all P values were >.13).

CONCLUSION

Internal carotid artery peak systolic velocities decrease with advancing age and increase with increasing pulse pressure. The effects of blood pressure at the time of scanning are small, but isolated systolic hypertension could cause increases in spurious velocity.

Value of prone positioning in the ultrasonographic diagnosis of gallstones: prospective study

To determine prospectively the value of prone/postprone positioning in the sonographic detection of gallstones, 682 patients were scanned in the recumbent, erect, and prone or postprone positions. The gallbladder was evaluated for an intraluminal hyperechoic focus, shadowing, and gravitational dependence and was identified in 679 patients. Among these, 28% had cholelithiasis. In five cases, prone positioning alone revealed gallstones. In 11 of 140 cases, gravitational dependence was only seen with prone scanning. The gallbladder was seen more frequently when the patients were prone than erect. Prone or postprone scanning is a useful supplement to the gallbladder examination, allowing increased demonstration of gravitational dependence and increased stone detection.

Physician training requirements in sonography: how many cases are needed for competence?

OBJECTIVE

Physician competence in the performance of sonographic studies was assessed after their involvement in predetermined increments of cases to determine whether the case volumes currently required by the American Institute of Ultrasound in Medicine and the American College of Radiology for training in sonography can be lowered substantially.

MATERIALS AND METHODS

Sonographic competence tests were administered to 10 first-year diagnostic radiology residents after their involvement in increments of 50 cases, up to a total of 200 cases (four competency tests). Each competency test consisted of the resident's independently scanning and interpreting 10 clinically mandated studies that were scored in comparison with the examination performed by the sonographer and interpreted by an attending radiologist. Trainee studies were graded on the percentage of anatomic landmarks depicted, the number of reporting errors, the number of clinically significant reporting errors, and the percentage of cases receiving a passing score.

RESULTS

Although resident performance improved progressively with increasing experience for all parameters assessed, performance of the group was poor even after their involvement in 200 cases. At this testing level, the mean percentage of anatomic landmarks depicted successfully was 56.5%; the mean total reporting errors per case was 1.2; the mean clinically significant errors per case was 0.5; and the mean percentage of cases receiving a passing score was 16%. Impressive performance differences were observed among residents for all parameters assessed, and these differences were not explained by the number of months of radiology training the resident had taken before the sonography rotation.

CONCLUSION

Involvement in 200 or fewer cases during the training period is not sufficient for physicians to develop an acceptable level of competence in sonography.

What is the upper limit of normal for the common bile duct on ultrasound: how much do you want it to be?

Conventionally, the upper limit of normal for the common bile duct as measured by ultrasound is considered to be 6 mm. This review is a somewhat personalized account of how that number became the convention and cautions the reader to avoid being slavish in the use of this number. Two specific cautions are not to apply this limit to older patients and to consider where in the common bile duct the measurement was taken, as measurements taken closer to the pancreas may be larger than ones closer to the liver.

Vertebral artery Doppler waveform changes indicating subclavian steal physiology

OBJECTIVE

The goal of this study was to characterize and classify changes in antegrade vertebral artery waveforms that may represent the early stages of subclavian steal physiology.

SUBJECTS AND METHODS

A prospective examination of waveforms from 1914 vertebral arteries produced a total of 40 that had a transient sharp decline in velocities at mid or late systole. In these patients, an ECG tracing was synchronized with the pulsed Doppler waveform, and reactive hyperemia was induced in the ipsilateral arm with a blood pressure cuff. The same protocol was performed in a control group of 52 patients with normal vertebral artery waveforms. Correlation between the waveforms and subclavian disease shown on angiography was made in 10 cases collected from the prospective study and in an additional 10 cases identified from a record search.

RESULTS

Four prototypic waveforms were identified on the basis of the degree of flow deceleration in mid systole. Flow velocity at the nadir of the mid systolic notch was greater than that of the end diastole for type 1 waveforms, equal to the end diastole for type 2, at the baseline for type 3, and below the baseline for type 4. The blood pressure cuff maneuver induced a change to more abnormal waveforms in 36 of 40 patients but did not change the waveforms of the control group. The correlation between waveform type and subclavian disease was statistically significant (p = 0.03).

CONCLUSION

Identifiable changes in the pulse contour of antegrade vertebral artery waveforms seem to represent the early stages of subclavian steal physiology. These changes can be organized into waveform types that indicate increasingly abnormal hemodynamics.

Refractory shadowing from pelvic masses on sonography: a useful diagnostic sign for uterine leiomyomas

OBJECTIVE

Our objective was to determine the diagnostic usefulness of sonography for revealing a recurrent acoustic shadowing pattern when imaging for possible uterine leiomyoma.

SUBJECTS AND METHODS

During an 18-month period, all pelvic masses discovered on sonography were prospectively examined for recurrent refractory shadows. Sonograms of 222 masses with a definitive final diagnosis were reviewed by two radiologists unaware of the follow-up results. Each mass was analyzed for the presence of three or more recurrent refractory shadows, each of which did not arise from an echogenic lead point. After all masses were rated independently, a consensus rating was reached for any discrepancy between observers.

RESULTS

Of the 222 masses, 152 (68%) were leiomyomas. The remainder resulted from a wide variety of other uterine and adnexal disorders. Agreement between the two observers regarding refractory shadows was excellent. Kappa coefficients were 0.86 at transabdominal and 0.96 at transvaginal approaches. Sensitivity of the refractory shadow pattern for leiomyomas was higher for transvaginal (87%) than for transabdominal (52%) sonography. Specificity of the refractory shadow pattern was 89% for transvaginal and 92% for transabdominal sonography. Using logistic regression analysis, we found a statistically significant association between a refractory shadowing pattern and leiomyoma for both transabdominal and transvaginal sonography (p < 0.001).

CONCLUSION

Recurrent refractory shadowing in a pelvic mass on sonography is highly suggestive of leiomyoma and can be a useful diagnostic clue for distinguishing leiomyomas from other pelvic masses.

PACS in sonography: accuracy of interpretation using film compared with monitor display. Picture archiving and communication systems

OBJECTIVE

The goal of this study was to determine the relative accuracy of interpretation of sonography when viewed on a monitor or on film.

MATERIALS AND METHODS

Four radiologists twice interpreted a series of 440 sonograms using the following sequences of display formats for initial and second interpretations: film-film, film-monitor, monitor-film, and monitor-monitor. Reporting discrepancies between the initial and subsequent interpretation were reviewed by an arbitration panel unaware of the display mode. Results were analyzed for differences in error rate attributable to film versus monitor display format, chronology of interpretation, individual observer, and observer seniority.

RESULTS

We found no statistically significant difference in the error rate for film (10.3%) versus monitor display format (14.6%) (p = .09). Likewise, we found no significant differences in the error rates attributable to chronology of interpretation (p = .13), individual observer (p = .54), or observer seniority (p = .87).

CONCLUSION

Interpretative accuracy is similar whether sonograms are interpreted on a monitor or on film.

Antenatal ultrasonographic diagnosis of rhizomelic chondrodysplasia punctata

Rhizomelic chondrodysplasia punctata is an autosomal recessive disorder characterized by stippled epiphyses and rhizomelic shortening of the long bones. Most fetuses with the disorder die in utero or shortly thereafter, and the few that survive suffer severe debility and profound mental retardation. Death ensues in the first decade of life. Relatively few reports discuss antenatal ultrasonographic diagnosis of rhizomelic chondrodysplasia punctata. We describe the prospective antenatal diagnosis of rhizomelic chondrodysplasia punctata in a fetus with no family history of the disorder, based on the sonographic findings of severe rhizomelic limb shortening in combination with premature ossification and stippling of multiple epiphyses. The ultrasonographic features and differential diagnosis of rhizomelic chondrodysplasia punctata are elaborated.

Enlarged fetal gallbladder: prognostic importance for aneuploidy or biliary abnormality at antenatal US

PURPOSE

To test the strength of the association of cholecystomegaly with aneuploidy and biliary abnormality and to assess the prognostic importance of the detection of an enlarged fetal gallbladder at antenatal ultrasonography (US).

MATERIALS AND METHODS

Gallbladder size was prospectively evaluated during 842 consecutive second-and third-trimester US examinations in 775 fetuses. The area of the gallbladder was calculated on the image that depicted the maximal gallbladder size, and the actual gallbladder areas was compared with the gallbladder area expected on the basis of the gestational age. Fetuses with an enlarged gallbladder were followed up.

RESULTS

Forty-three fetuses had an enlarged gallbladder (area more than 2 SDs above the mean for gestational age). Outcome was normal in 38 of the 39 fetuses who could be followed up. With the exception of a single baby with an isolated ventricular septal defect, which closed spontaneously, none of the babies with an enlarged fetal gallbladder had structural anatomic defects or evidence of aneuploidy or a biliary tract abnormality.

CONCLUSION

Identification of an enlarged gallbladder at antenatal US does not appear to be associated with a substantially increased risk of chromosomal aneuploidy or biliary tract malformation.

Fetal cerebral ventriculomegaly: misidentification of the true medial boundary of the ventricle at US

PURPOSE

To investigate the implications of mistaking the medial surface of the cerebral hemisphere for the medial wall of the lateral ventricle at antenatal ultrasonography (US) and to identify US clues that might help avoid this interpretive error.

MATERIALS AND METHODS

In 50 second- and third-trimester fetuses, a directed attempt was made to demonstrate the medial surface of the cerebral hemisphere and the medial wall of the lateral ventricle on images that depicted the lateral wall of the ventricle. In each fetus, measurements of the diameter of the false ventricular atrium were compared with the true diameter of the lateral ventricle to assess the potential magnitude of error.

RESULTS

The average diameter measured with the medial surface of the cerebral hemisphere was 10.7 mm, compared with the true mean ventricular diameter of 6.2 mm. This value was greater than or equal to 10 mm (the generally accepted upper limit of normal for the ventricular diameter) in all 15 third-trimester fetuses and in 16 (46%) of 35 second-trimester fetuses. The parietal occipital fissure was demonstrated along the medial surface of the cerebral hemisphere in 36 (72%) of 50 fetuses, and the medial surface of the cerebral hemisphere could be traced posteriorly around the occipital lobe in 45 (90%).

CONCLUSION

When ventriculomegaly is suspected, the examiner should make a direct attempt to find the medial wall of the ventricle and distinguish it from the medial boundary of the cerebral hemisphere. Correct identification of the anatomic interfaces is facilitated by demonstrating that the cerebral interface contains the parietal occipital fissure and can be traced posteriorly around the occipital lobe.

Third ventricle: size and appearance in normal fetuses through gestation

PURPOSE

To define the size and appearance of the normal fetal third ventricle.

MATERIALS AND METHODS

The third ventricle was prospectively assessed in 441 consecutive normal second- and third-trimester fetuses. The fetuses were divided into six gestational age ranges. Data regarding the size and configuration of the third ventricle were analyzed for each group.

RESULTS

The third ventricle was seen in 435 of 440 (98.9%) fetuses. It appeared as a single echogenic line between the thalami in 171 (38.9%) fetuses, as parallel echogenic lines outlining a fluid-filled lumen in 243 (55.2%) fetuses, and as divergent lines delineating a V-shaped fluid-filled structure in 21 (4.8%) fetuses. The single-line configuration was most common early in the second trimester. Later in pregnancy, the ventricle walls could be discerned as separate parallel or divergent lines outlining a fluid-filled lumen. The average width of the ventricle was relatively constant at approximately 1 mm from 12 to 28 weeks. After this time, it enlarged, reaching a maximum 1.9 mm.

CONCLUSION

The third ventricle can be imaged in most second- and third-trimester fetuses. Its size and configuration evolve through the second and third trimesters. This evolution must be considered in the evaluation of normality. At any gestational age, a third ventricle greater than 3.5 mm in width should be viewed with concern for abnormality.

Nonvisualization of the fetal gallbladder: frequency and prognostic importance

PURPOSE

To assess the frequency of fetal gallbladder visualization through gestation and to determine the prognostic importance of nonvisualization.

MATERIALS AND METHODS

Demonstration of the gallbladder was prospectively attempted in 578 consecutive second- and third-trimester obstetric ultrasound examinations. Data regarding gallbladder visualization were stratified into subgroups on the basis of estimated gestational age. Postnatal follow-up was performed in 80 fetuses with nonvisualization of the gallbladder.

RESULTS

The gallbladder was seen on 477 of 578 (82.5%) fetal sonograms. The likelihood of gallbladder visualization increased with advancing gestational age, reaching a plateau of approximately 95% between 24 and 32 weeks. After 32 weeks, the frequency of visualization declined. Seventy-five of the 80 fetuses with nonvisualized gallbladders who underwent follow-up had normal outcomes. Except for one fetus with trisomy 21, all fetuses with abnormalities had relatively minor, non-life threatening problems that did not involve the gallbladder or biliary tract.

CONCLUSION

Most fetuses with nonvisualization of the gallbladder have normal outcomes. The rate of nonvisualization of the fetal gallbladder is sufficiently high to undermine the utility of gallbladder visualization as a screen for fetal abnormality.

Can the US examination for lower extremity deep venous thrombosis be abbreviated? A prospective study of 755 examinations

PURPOSE

To determine if the ultrasound (US) survey of the lower extremity for deep venous thrombosis (DVT) can be curtailed without compromising diagnostic efficacy.

MATERIALS AND METHODS

The authors performed 755 US examinations in 721 patients (1,024 lower extremities) referred for suspicion of lower extremity DVT. The full lengths of the deep veins were studied, and findings were categorized at five locations: common femoral vein (CFV), proximal superficial femoral vein (CFV), mid-SFV, distal SFV, and popliteal vein (PV).

RESULTS

Acute thrombus was seen in one or more veins in 131 (17.4%) of the 755 examinations. DVT isolated to a single vein was seen in 28 (21.4%) of the 131 positive examinations: DVT was limited to the CFV in eight studies (61%), to the SFV in six studies (4.6%), and to the PV in 14 studies (10.7%).

CONCLUSIONS

DVT limited to a single vein occurs with sufficient frequency that the US screening survey cannot be abbreviated without loss of diagnostic efficacy.

Ultrasonographically guided manual compression of femoral artery injuries

To determine the success and complication rates of ultrasonographically guided manual compression in patients with femoral arterial injuries after femoral arterial catheterization, we performed 53 sonographically guided compression repairs in 51 patients. Ultrasonographically guided compression repair was performed on 40 pseudoaneurysms in non-anticoagulated patients, seven pseudoaneurysms in anticoagulated patients, four arteriovenous fistulas on non-anticoagulated patients, and one pseudoaneurysm combined with an arteriovenous fistula. One pseudoaneurysm underwent two separate ultrasonographically guided compression repairs: once when the patient was anticoagulated and once after anticoagulants were withheld. Ultrasonographically guided compression repair was successful in 37 of 48 pseudoaneurysms (77%). Of the 40 pseudoaneurysms in non-anticoagulated patients, ultrasonographically guided compression repair was successful in 36 (90%). This repair technique failed in all seven pseudoaneurysms in anticoagulated patients. Ultrasonographically guided compression repair was successful in 13 of 16 (81%) multilobulated pseudoaneurysms but failed in all arteriovenous fistulas and the one case of pseudoaneurysm combined with an arteriovenous fistula. Ultrasonographically guided compression repair is a safe and effective alternative to surgery for the repair of pseudoaneurysms, including multilobulated pseudoaneurysms. The procedure does not appear to be effective in the anticoagulated patient or in patients with an arteriovenous fistula.

Acoustic shadowing from uterine leiomyomas: sonographic-pathologic correlation

PURPOSE

To investigate the origin of discrete shadowing from uterine leiomyomas at ultrasound (US) that does not progress from an echogenic origin.

MATERIALS AND METHODS

Seven hysterectomy specimens with leiomyomas were scanned in a water bath. With US guidance, 13 self-retaining needles were placed at the origin of shadows that did not (12 cases) or did (one case) arise from an echogenic focus. The localized tissues were inspected for gross pathologic features and microanatomic detail.

RESULTS

In the 12 cases, the shadow originated from transitional zones: the margins of the fibroid with adjacent myometrium (three needles), the edges of nodular whorls of smooth muscle (four needles), and the margin between smooth muscle bundles and hyalinized connective tissue (five needles). There was no evidence of calcification, hemorrhage, or necrosis. In the other case, microcalcifications were found.

CONCLUSION

Discrete shadowing not arising from echogenic foci resulted from the structural features of the leiomyomas and occurred at transitional boundaries between juxtaposed tissue types or at the curved margins of organized anatomic structures.

Fetal bifid sacrum artifact: normal developmental anatomy simulating malformation

PURPOSE

To determine the clinical importance and origin of a bifid configuration of the fetal sacrum seen during routine fetal sonography.

MATERIALS AND METHODS

An apparent bifid malformation of the sacral spine was seen in 24 fetuses at antenatal sonography. An attempt was made to recreate this configuration prospectively in 111 consecutive second- and third-trimester fetuses. Three cadavers were also imaged to determine the origin of this configuration.

RESULTS

Outcome information was available for 22 of the 24 fetuses; all fetuses were normal. In the prospective study, the bifid sacrum configuration was recreated in 75 of the 111 fetuses studied. The configuration could never be produced earlier than 20 weeks gestational age, was seen in some fetuses at 20-25 weeks, and could always be seen after 25 weeks. Findings from imaging studies of the three cadavers revealed that this configuration was dependent on the demonstration of the alar ossification centers of the sacral vertebra.

CONCLUSION

The bifid sacrum artifact is a skewed representation of normal anatomy and should not be interpreted as a true anomaly.

Fetal renal vein thrombosis, hydrops fetalis, and maternal lupus anticoagulant. A case report

Hydrops fetalis with fetal renal vein thrombosis in a mother with antiphospholipid antibody syndrome detected post-partum suggests an underlying pathogenetic association that may provide new strategies for treatment of a lethal disorder.

Fetal fourth ventricle: US appearance and frequency of depiction

PURPOSE

To define the normal appearance of the fetal fourth ventricle throughout gestation and ascertain an expected frequency of depiction at different gestational ages.

MATERIALS AND METHODS

Three hundred ten consecutive second- and third-trimester fetuses were studied with ultrasound. The posterior fossa was examined to document the size and appearance of the fourth ventricle.

RESULTS

The fourth ventricle was seen in 221 of the 310 fetuses (71.3%) and was most consistently demonstrated in the middle of the second trimester. At this stage of gestation, the fourth ventricle was almost always seen when the anatomic features of the posterior fossa were identified. The mean anteroposterior dimension of the fourth ventricle was 3.5 mm +/- 1.3 (standard deviation), and the mean width was 3.9 mm +/- 1.7.

CONCLUSION

The fetal fourth ventricle can be seen in most fetuses beginning in the middle of the second trimester and increases in size with advancing gestation. It can be difficult to depict before the middle of the second trimester and late in the third trimester.

Choroid plexus-ventricular wall separation in fetuses with normal-sized cerebral ventricles at sonography: postnatal outcome

OBJECTIVE

The choroid plexus typically fills the atrium of the lateral ventricles of the brain in normal fetuses, but separates from the medial ventricular wall with increasing ventriculomegaly. Sonographic depiction of choroid plexus-ventricular wall separation has been associated with a high frequency of unfavorable outcomes in fetuses with mild ventricular dilatation. This separation, however, is also observed in a small subgroup of fetuses with normal ventricular measurements. The objective of this study was to ascertain the prognosis for fetuses when choroid plexus-ventricular wall separation and normal-sized lateral ventricles are seen on antenatal sonograms.

MATERIALS AND METHODS

Postnatal follow-up was reviewed for 74 fetuses showing a 3 mm or greater separation between the choroid plexus and the medial ventricular wall and normal-sized (< or = 10 mm) ventricles on antenatal sonograms. Fetuses were divided into normal and abnormal outcome groups, and the data were analyzed to determine if the amount of separation, the ventricular atrial diameter, or the evolution of these findings on follow-up sonograms was predictive of outcome.

RESULTS

Fifty-nine patients (80%) had normal outcomes (defined as no congenital anomalies and no significant subsequent medical history apart from usual infant and childhood illnesses) and 15 patients (20%) had abnormal outcomes. The severity of the abnormalities varied widely, ranging from relatively inconsequential, such as isolated polydactyly, to complex congenital malformation syndromes resulting in neonatal death. No consistent pattern of malformation was evident. Although we found a statistically significant difference in the degree of choroid plexus-ventricular wall separation when fetuses were separated into normal and abnormal outcome groups, the range of measurements obtained in these two populations overlapped considerably. Outcomes were normal in all 13 patients in whom the choroid plexus-ventricular wall separation had returned to normal by the time of the last antenatal sonogram.

CONCLUSION

A separation of 3 mm or greater between the choroid plexus and the medial ventricular wall is an important finding that is associated with an increased risk of an abnormal outcome even in the subpopulation of fetuses with normal-sized ventricles. Although the outcome will be normal in the majority (80%) of such fetuses, identification of choroid plexus-ventricular wall separation mandates a meticulous examination of fetal anatomy.

Deep venous thrombosis: value of self-augmentation US evaluation

In 10 healthy volunteers (three men and seven women, aged 24-35 years [mean, 27 years]) and 28 patients (11 men and 17 women, aged 38-74 years [mean, 60 years]) with symptoms for deep venous thrombosis (DVT), self-augmentation ultrasound (US) scanning was performed. The technique resulted in diagnostically useful venous flow augmentation in the femoropopliteal veins in all 10 (100%) limbs of volunteers, in 25 of 27 (93%) limbs of patients without DVT, and in two of seven (29%) limbs of patients with DVT. Of the patients in whom self-augmentation failed, two could not perform the maneuver and five had scans positive for DVT.

Fetal biometry in the Brachmann-de Lange syndrome

The Brachmann-de Lange syndrome (BDLS) is diagnosed in children on the basis of a distinctive clinical phenotype which includes retarded physical growth. Because there are no genetic or biochemical tests at present, the antenatal detection of the syndrome may depend upon identification of some aspect of the phenotype in the fetus using ultrasound imaging. We studied the growth of 23 subsequently diagnosed fetuses with the BDLS using standard biometric parameters defined by prenatal ultrasound imaging. Sonographic studies were obtained through a national parents' group, the Cornelia de Lange Syndrome Foundation. Assessment of fetal growth was made using four standardized measurements: the biparietal diameter, head circumference, femur length, and abdominal circumference. These values were compared to established tables of normal fetal growth and established ratios of fetal body proportions. The cross-sectional growth curve derived using all measurements collected as a composite group indicates that growth retardation would be first detected as early as 25 weeks. In five fetuses with measurements both before and after 25 weeks of gestation, longitudinal growth curves indicated that the diagnosis of "small for gestational age" would have been suggested between 20 and 25 weeks. The mean fetal weight estimates closely followed the fifth centile curve of normal fetuses both before and after 25 weeks. Cephalic indices in BDLS fetuses indicated either frank brachycephaly (25%), or were at the upper portion of the normal range. Femur lengths were relatively short (less than 90% of their expected length) ion 4 of the 11 fetuses where such information could be obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Complications of cesarean section: role of transperineal US

The pelvic area was prospectively examined with transabdominal and transperineal ultrasonography (US) in 22 patients referred for US evaluation for possible complications of cesarean section. The region of the uterine wound was seen with transabdominal US in all patients and with transperineal US in 20. The two in whom transperineal US did not reveal the lower uterus had undergone scanning with their bladders empty. Bladder flap hematomas were revealed with transabdominal US in 10 patients and with transperineal US in nine. Transabdominal and transperineal diagnoses regarding bladder flap hematoma were in agreement in all 19 patients who underwent transperineal US with a distended urinary bladder. With the transabdominal approach, subfascial hematomas were seen in nine patients, but none were revealed with the transperineal technique. In one patient, a hematoma in the space of Retzius was seen only with transperineal US. These findings indicate that transperineal US can complement transabdominal US in evaluation for complications of cesarean section.

Doppler US assessment of maternal kidneys: analysis of intrarenal resistivity indexes in normal pregnancy and physiologic pelvicaliectasis

Duplex ultrasound was performed in both kidneys of 156 normotensive pregnant women without suspected renal disease and 25 nonpregnant women of childbearing age to determine if resistivity indexes are different between pregnant and nonpregnant women and to assess whether the "physiologic" pelvicaliectasis of pregnancy causes elevated resistivity indexes. The mean intrarenal resistivity index for pregnant patients was 61.1, and that for nonpregnant women was 61.0. There were no statistically significant differences between the resistivity indexes of pregnant and nonpregnant women, regardless of whether the pregnant patients were considered as a composite group or subdivided by trimester. Twenty-nine right kidneys and four left kidneys in pregnant patients had moderate dilation of the collecting system attributed to physiologic pelvicaliectasis of pregnancy. No statistically significant differences were detected between the resistivity indexes of kidneys with and without pelvicaliectasis. Normal, uncomplicated pregnancy has no significant effect on resistivity indexes obtained in maternal kidneys. Physiologic pelvicaliectasis of pregnancy is likely to be partially a result of obstruction; this too, however, is not reflected by changes in resistivity indexes. An elevated resistivity index during pregnancy should not be attributed to the normal physiologic changes of pregnancy.

Diagnosis of placenta previa during the third trimester: role of transperineal sonography

Placenta previa can be difficult to diagnose with transabdominal sonography during the third trimester of pregnancy, because of difficulties in imaging the cervix late in pregnancy. Although transperineal sonography offers an additional view of the cervix, its value in the diagnosis of placenta previa has not been studied. Accordingly, we performed transperineal sonography on 164 patients who had had transabdominal scans that had shown placenta previa or had been inconclusive during the third trimester of pregnancy. Transabdominal sonograms had been inconclusive for placenta previa in 157 of these patients because the cervix was not visualized. The remaining seven patients had transabdominal scans that showed placenta previa. Transperineal sonography successfully visualized the internal surface of the cervix in all 164 patients, allowing determination of the presence or absence of placenta previa in all cases. Transperineal sonograms showed absence of placenta previa in 154 patients. At delivery, none of these patients had evidence of placenta previa. Transperineal sonography showed placenta previa in 10 patients. In nine of these patients, placenta previa was confirmed at delivery. The 10th patient did not have clinically significant placenta previa at delivery. Our study shows that transperineal sonography is a valuable technique to complement transabdominal sonography for detection of placenta previa during the third trimester of pregnancy. Use of transperineal sonography should be strongly considered when a definitive diagnosis regarding placenta previa is not possible by transabdominal sonography because the cervix is not visualized. In such cases, transperineal sonography will usually show the internal surface of the cervix without overlying placental tissue, allowing confident exclusion of placenta previa. Occasionally, however, transperineal sonography will show a placenta previa that was not seen with transabdominal sonography.

Sonography of the cervix during the third trimester of pregnancy: value of the transperineal approach

Transabdominal sonography reliably depicts the cervix during the first and second trimesters of pregnancy, but cervical visualization becomes increasingly difficult as the third trimester progresses. To evaluate the possibility of using a perineal approach to bypass the fetus and image the cervix during the third trimester, we used transperineal sonography to image the cervix of 158 third-trimester patients in whom transabdominal visualization was inadequate. The internal os and upper cervix were successfully visualized on transperineal sonograms in all 158 patients, but the region of the external os was obscured by rectal gas in 22 (14%) cases. In some patients in whom the external portion of the cervix was obscured by bowel gas, the problem could be overcome by scanning with the patient in the lateral decubitus position or by rotating the patient. Transperineal sonography is an effective technique for imaging the cervix during the third trimester of pregnancy, allowing cervical visualization in most patients in whom transabdominal sonography of this area is unsuccessful.

Transperineal US: alternative technique to improve visualization of the presenting fetal part

Transperineal ultrasound (TPU) was used as an alternative imaging technique to evaluate the anatomy of the presenting part in 27 second- and third-trimester fetuses when transabdominal ultrasound (US) images were suboptimal. Use of TPU improved visualization of the distal fetal spine in 20 of 21 breech cases, providing sufficient information regarding bone anatomy to rule out splaying of the posterior elements. In addition, the intact skin surface overlying the distal spine, not seen at transabdominal US, was well demonstrated at TPU in 18 of these fetuses. TPU was used to improve assessment of intracranial anatomy in six cases with a cephalic presentation in which the fetal head was located low in the maternal pelvis and could not be adequately visualized with the transabdominal technique. In one of these cases, TPU offered improved visualization of anencephaly. Use of TPU should be considered to optimize visualization of the presenting fetal part when results at transabdominal US are suboptimal and the poorly seen part overlies the maternal cervix.

Value of sonography in the diagnosis of intracranial hemorrhage and periventricular leukomalacia: a postmortem study of 35 cases

Periventricular leukomalacia and germinal matrix hemorrhages are major causes of neurodevelopmental abnormalities in the premature neonate. Although sonography is widely used to detect these abnormalities and is thought to be sensitive for hemorrhages and the later cystic stages of periventricular leukomalacia, its sensitivity for the more acute phase of periventricular leukomalacia remains to be determined. It has been difficult to study this issue because periventricular leukomalacia often is not lethal, and in postmortem studies there is usually a considerable interval between the time of in vivo imaging, if any, and the death of the patient. A "prospective" autopsy study was performed on brain specimens from infants who died at less than 1 year of age during a 10-month period. Thirty-five formalin-fixed brains were studied and sonographic images of these specimens were compared with histologic findings in whole brain sections to determine the sensitivity and specificity of sonography for the detection of germinal matrix hemorrhage and periventricular leukomalacia. Sonography identified germinal matrix hemorrhages as small as 5 mm, although smaller lesions were not visualized. Postmortem sonography had a sensitivity of 27% and specificity of 88% for all germinal matrix hemorrhages, but a sensitivity of 100% and specificity of 91% for hemorrhages larger than 5 mm. Periventricular leukomalacia, seen as hyperechoic areas in the periventricular white matter, was not detected as readily. For periventricular leukomalacia, the overall sensitivity and specificity were 50% and 87%, respectively. We conclude that sonography is useful for detecting the larger germinal matrix hemorrhages, but has more limited sensitivity in the early diagnosis of periventricular leukomalacia.

Fetal umbilical artery Doppler response to graded maternal aerobic exercise and subsequent maternal mean arterial blood pressure: predictive value for pregnancy-induced hypertension

Predictive tests for the identification of women at high risk of the development of preeclampsia are critical to allow the most appropriate preventive measures. Preeclampsia is a vasospastic condition of pregnancy characterized by early and enhanced vascular reactivity to endogenous pressor agents. Exercise tolerance testing with cycle ergometry to induce hemodynamic response measured with duplex Doppler A/B ratio of the umbilical artery could unmask latent vascular pressor hypersensitivity. Our prospective cohort study was designed to test the efficacy of the American College of Obstetricians and Gynecologists exercise in pregnancy guidelines for the low-risk athletic, physically active, or sedentary patient. The pattern of fetal response to material exercise testing at 28 weeks' gestation was compared with subsequent maternal mean arterial blood pressure and the development of pregnancy-induced hypertension and preeclampsia. Doppler A/B ratio during the recovery period was assessed as below baseline (18) or elevated above resting baseline values (12). Third-trimester blood pressure pattern was assessed to be elevated in 11 patients, 10 of whom had elevated recovery A/B ratios. The Fisher exact test results were (p = 0.00002) positive predictive value, 83%; negative predictive value, 94%; sensitivity, 91%; and specificity, 89%. Preeclampsia developed in four patients; all had elevated recovery A/B ratios. Fisher exact test results were (p = 0.01806) positive predictive value, 33%; negative predictive value, 100%; sensitivity, 100%; and specificity, 69%.

Femur length in the US prediction of trisomy 21 and other chromosomal abnormalities

After review of 461 consecutive amniocentesis examinations, 428 fetuses with normal karyotype and 13 with chromosomal abnormalities were analyzed. Six of the abnormal fetuses had trisomy 21, and seven had other chromosomal abnormalities. The ratio of measured-to-expected femur length (MFL/EFL) was determined for each fetus. The MFL/EFL values were 1.0 +/- 0.7 (mean +/- standard deviation) for the control group, 0.94 +/- 0.06 for trisomy 21 fetuses, 0.94 +/- 0.10 for non-trisomy 21 fetuses, and 0.94 +/- 0.08 for the entire group of fetuses with chromosomal abnormalities. The mean MFL/EFL value for the abnormal fetuses differed significantly from that for the control group (P less than .003). An MFL/EFL of 0.90 or less resulted in a sensitivity of 46.2% and a specificity of 94.1% for detection of all chromosomal abnormalities. For detecting trisomy 21, the sensitivity and specificity were 50% and 93.5%, respectively. Assuming a pretest probability for trisomy 21 of one in 250, an MFL/EFL of 0.90 or less resulted in a positive predictive value of 3%. It is concluded that an MFL/EFL of less than 0.90 modifies the relative risk for chromosomal abnormalities and may significantly influence the decision for amniocentesis.

Fetal gastrointestinal abnormalities

A wide range of abnormalities of the fetal gastrointestinal tract is currently detectable by antenatal sonography, but the sonographic appearance of normal fetal bowel is variable, with considerable overlap between normal and abnormal patterns. In examining the major gastrointestinal disorders that may be recognized by in utero sonography, this article emphasizes potential pitfalls due to confusion with normal anatomic variants and pathologic processes arising elsewhere in the fetus.

Value of sonography in the diagnosis of intracranial hemorrhage and periventricular leukomalacia: a postmortem study of 35 cases

Periventricular leukomalacia and germinal matrix hemorrhages are major causes of neurodevelopmental abnormalities in the premature neonate. Although sonography is widely used to detect these abnormalities and is thought to be sensitive for hemorrhages and the later cystic stages of periventricular leukomalacia, its sensitivity for the more acute phase of periventricular leukomalacia remains to be determined. It has been difficult to study this issue because periventricular leukomalacia often is not lethal, and in postmortem studies there is usually a considerable interval between the time of in vivo imaging, if any, and the death of the patient. A "prospective" autopsy study was performed on brain specimens from infants who died at less than 1 year of age during a 10-month period. Thirty-five formalin-fixed brains were studied and sonographic images of these specimens were compared with histologic findings in whole brain sections to determine the sensitivity and specificity of sonography for the detection of germinal matrix hemorrhage and periventricular leukomalacia. Sonography identified germinal matrix hemorrhages as small as 5 mm, although smaller lesions were not visualized. Postmortem sonography had a sensitivity of 27% and specificity of 88% for all germinal matrix hemorrhages, but a sensitivity of 100% and specificity of 91% for hemorrhages larger than 5 mm. Periventricular leukomalacia, seen as hyperechoic areas in the periventricular white matter, was not detected as readily. For periventricular leukomalacia, the overall sensitivity and specificity were 50% and 87%, respectively. We conclude that sonography is useful for detecting the larger germinal matrix hemorrhages, but has more limited sensitivity in the early diagnosis of periventricular leukomalacia.

Normal sonographic appearance of the fetal neck late in the first trimester: the pseudomembrane

A linear specular reflection simulating a membrane was visualized along the back of the neck on sonograms of ten normal fetuses ranging in age from 10 to 14 menstrual weeks. Follow-up ultrasound studies of eight of the fetuses and postpartum clinical examinations of all subjects were normal, revealing no evidence of neck abnormalities. Although this pseudomembrane is similar in appearance to published examples of early cystic hygroma, it is a normal finding that can be distinguished from early cystic hygroma on the basis of its less bulbous appearance and the absence of underlying septations. This structure corresponds in distribution to the skin along the back of the fetus and likely represents a specular reflection from the skin surface.

Augmentation and replacement cystoplasty: sonographic findings

Sonographic evaluation of the urinary tract after bladder augmentation and replacement procedures often reveals unexpected findings that result from incorporation of bowel into the urinary bladder wall. Familiarity with such findings is important to avoid misinterpreting them as abnormalities. The authors reviewed the sonograms of 47 patients. The most common findings were thick or irregularly shaped bladder walls (96%), pseudomasses within the bladder lumen (89%), and fine debris or linear strands (47%). Pseudomasses were potentially the most confusing; they are usually attributable to normal bowel folds, intraluminal mucus collections, or segments of bowel that have been intussuscepted into the bladder to prevent reflux.

The three lines: origin of sonographic landmarks in the fetal head

Antenatal sonography consistently reveals three parallel echogenic lines on high-axial scans of the fetal head. Previous descriptions of fetal intracranial anatomy assumed that the inner line originates from the interhemispheric fissure and that the outer lines originate from the lateral walls of the lateral ventricles. By studying the three lines sonographically in 25 fetuses and by injecting contrast material into the deep venous system of autopsy specimens, we showed that the outer two lines do not represent the lateral walls of the lateral ventricles, but rather appear to arise from deep intracerebral veins. This finding challenges the validity of lateral ventricular hemispheric ratios in the diagnosis of early hydrocephalus, since such calculations assume that the outer lines originate from the ventricular walls rather than from veins. The results of this study reveal that the two outer lines most likely originate from deep cerebral veins, rather than from the lateral walls of the lateral ventricles.

Percutaneous drainage of pelvic lymphatic fluid collections in the renal transplant patient

Seventeen renal transplant patients with pelvic lymphatic fluid collections were treated with percutaneous drainage. Eleven of 16 patients with lymphoceles (69%) were successfully managed without surgery, although seven of these patients required repeat catheter insertions, and three patients developed local infections. The patient with an ovarian cystadenoma was treated with surgery. The mean duration of catheter insertion was ten days for initial drainage and 16 days for repeat drainage. Elevated serum creatinines decreased in 14 of the patients with lymphoceles (88%), including all five patients without pelvocaliectasis, but never returned to baseline in six instances. This observation may reflect the inadequate therapy of frequently encountered concurrent renal parenchymal abnormalities (rejection, cyclosporine toxicity, acute tubular necrosis). While percutaneous management of lymphoceles is technically easy and usually ultimately effective, the interventional radiologist should be prepared for long duration of catheter insertions, repeat interventions, and variable clinical courses. Differentiation of lymphoceles from other fluid collections, such as cystic ovarian neoplasms, may be difficult.

Expectant management of partial placental abruption in previable pregnancies. A report of two cases

Placental abruption is a major cause of perinatal morbidity and mortality, especially in the preterm infant. Two patients had previable pregnancies complicated by placental abruption and large extraamniotic hematomas. Precise diagnosis and follow-up with real-time ultrasound allowed expectant management until the delivery of viable infants became possible.

Striated intramural gallbladder lucencies on US studies: predictors of acute cholecystitis

Ultrasound scans of 51 consecutive patients with gallbladder wall thickening were reviewed, and specific sonographic features were correlated with surgical and clinical follow-up. Two patterns of thickening were identified as specific indicators of the presence or absence of acute cholecystitis. "Striated" wall thickening, consisting of several alternating, irregular, discontinuous, lucent and echogenic bands, was seen in eight of 13 patients (62%) with acute cholecystitis. This pattern was not encountered in any of the patients who did not have acute cholecystitis. Conversely, "three-layer" thickening, consisting of a single circumferential lucent zone between two relatively uniform echogenic layers, was seen in only one of 13 patients (8%) with acute cholecystitis but in 11 of 38 patients (29%) with other diagnoses. Other abnormalities, including the presence of intramural echogenic foci and wall irregularities, were more frequently seen in patients with acute cholecystitis but were not as helpful. Use of these features may suggest or help exclude a diagnosis of acute cholecystitis in those patients in whom the cause of gallbladder wall thickening is otherwise not apparent.

Sonography of subfascial hematoma after cesarean delivery

Subfascial hematoma is an important complication of cesarean delivery that has received little attention in the radiologic literature. It results from extraperitoneal hemorrhage within the prevesical space, posterior to the rectus muscles and transversalis fascia but anterior to the peritoneum and umbilicovesical fascia. Subfascial hematomas were found in 12 (38%) of 32 patients referred for sonographic evaluation of a fever or a fall in hemoglobin that occurred after a cesarean delivery. In all cases, sonography revealed cystic or complex masses of various sizes anterior to the bladder. The use of high-frequency, short-focus transducers often was necessary to recognize these superficial abnormalities. Seven of the 12 patients had concomitant bladder-flap hematomas between the lower uterine segment and posterior bladder margin. Of the five remaining patients with isolated subfascial hematomas, the sonograms on four were misinterpreted as showing bladder-flap hematomas. The other was diagnosed correctly. Distinction of subfascial hematomas from bladder-flap hematomas and superficial-wound hematomas must be made if surgical evacuation is contemplated.

Epiphyseal ossification centers in the assessment of fetal maturity: sonographic correlation with the amniocentesis lung profile

The epiphyseal ossification centers of the distal femur (DFE) and proximal tibia (PTE) appear and enlarge during the third trimester of pregnancy. Late in the third trimester, the epiphysis of the proximal humerus (PHE) begins to ossify in some fetuses. Using the amniocentesis lung profile to determine the value of sonographic epiphyseal visualization as a predictor of pulmonary maturity, we studied 50 fetuses prospectively and compared the sonographic epiphyseal findings with results from the amniocentesis lung profiles. Nine fetuses with a visible PHE had a mature amniocentesis lung profile (accuracy of positive prediction = 100%), and then fetuses with an immature amniocentesis lung profile had no visible PHE (conegativity = 100%). Fetuses in which the combined DFE and PTE diameters were greater than 11 mm or in which the DFE and the PTE diameters were similar in size (DFE less than or equal to 1 mm larger than PTE) also yielded positive results. Copositivity and accuracy of prediction of an immature amniocentesis lung profile, on the other hand, were low (22%-25%) for the same epiphyseal parameters. These data suggest that antenatal visualization and measurement of the epiphyseal ossification centers of the fetal knee and shoulder may help to identify fetuses that would have a mature amniocentesis lung profile.

Value of sonographic screening for gallstones in patients with chest pain and normal coronary arteries

The prevalence of sonographically detectable gallstones in patients with chest pain and normal coronary arteries was compared with the prevalence of gallstones in patients referred to sonography for nonbiliary disease. Among 545 patients with chest pain and normal coronary arteriograms, 101 (18.5%) were referred for sonographic examination of the gallbladder. This test group was compared to a matched control group (n = 101) undergoing abdominal sonography for nonbiliary disease. Six patients (5.9%) in the test group and eight patients (7.9%) in the control group were found to have gallstones by accepted sonographic criteria. Studies based on oral cholecystogram screening of healthy populations have claimed a prevalence of cholelithiasis of 2.3%-6.2% for males and 2.3%-12% for females. The authors were unable to demonstrate a higher prevalence of sonographically identified gallstones in patients with chest pain and normal coronary arteries than in patients examined for nonbiliary disease. The frequency of gallstones in this test group is comparable to that reported for a screened population of healthy men and women.

Ultrasonically guided percutaneous transhepatic transcholecystocholangiography in the nondilated biliary tree

Five patients with CT or ultrasound-proven nondilated intrahepatic biliary radicles underwent ultrasound-guided percutaneous transhepatic transcholecystocholangiography (PTHTCC) for visualization of the biliary tree following failed endoscopic retrograde cholangiography. In no instance were more than 2 passes of a 22-gauge needle necessary to enter the gallbladder. Visualization of the biliary tree was excellent in all cases, and there were no complications. Therefore, PTHTCC is a safe and reliable method of visualizing the nondilated biliary tree.

Cranial ultrasonography of neonatal periventricular/intraventricular hemorrhage: who, how, why and when?

The sex, age, and cranial ultrasound (US) findings of 742 premature neonates evaluated over a 3-year period were reviewed retrospectively. Examinations were performed with a mechanical-sector real-time unit using a 5 MHz or 7.5 MHz transducer. The caudothalamic groove was carefully imaged with periventricular/intraventricular hemorrhage diagnosed by previously described criteria. Intracranial hemorrhage occurred in 44% of patients with 20% being Grade 1, 10% Grade 2, 7% Grade 3, and 7% Grade 4. All hemorrhages occurred during the first week of life. Computed tomography is superior to US for demonstrating parenchymal changes and extent of hypoxic damage. Based on our 3-year experience and a review of the literature, we propose an algorithm for cranial imaging of the preterm neonate. This ordered, sequential approach to the premature neonate with possible intracranial hemorrhage permits accurate initial diagnosis as well as appropriate follow-up for potential complications of ventricular dilatation, hydrocephalus, porencephaly, and hypoxic encephalomalacia.

Management of severe distress in a potentially anomalous preterm fetus

Unless there is unequivocal evidence of a congenital anomaly incompatible with life, expeditious delivery should be offered to the patient whose potentially viable fetus is showing evidence of severe distress. The patient should be informed of the difficulties in interpreting diagnostic testing as well as both the immediate risks and future implications of vertical cesarean delivery. Our case further suggests that ultrasonographically and echocardiographically detected congestive heart failure may actually help confirm the diagnosis of fetal distress rather than necessarily identify an anatomic cardiac anomaly.

Accuracy of ultrasound in fetal femur length determination. Ultrasound phantom study

An ultrasound phantom was constructed simulating fetal femurs in amniotic fluid. Bones of 26, 36, 50, 58, and 70 mm, representative of gestational ages ranging from 17 to 36 weeks, were scanned with mechanical sector, phased sector, and linear array systems (ATL, Diasonics, Acuson, and GE). Measurements were made with the bone in both a horizontal and nearly vertical orientation at 5, 10, and 15 cm from the transducer. The ultrasound measurements were compared with the true bone length. With bones in a nearly vertical orientation (parallel to the ultrasound beam) the ultrasound measurements corresponded more closely to the true bone length regardless of the type of equipment or distance from the transducer. The wide aperture linear system was most accurate with no measurable difference from the actual bone length and a mechanical sector scanner had the largest error which was 6 mm. In the horizontal position (perpendicular to the beam) the smallest errors occurred when the bone was in the focal zone. This ranged from no error for the wide aperture linear array to 8 mm for the mechanical sector scanner. When the bone was not in the focal zone the error ranged from 8 to 26 mm for the mechanical sector scanner. Errors in ultrasound-measured femur lengths can be shown to result from the focal characteristics of the equipment as well as the orientation and distance of the bone from the transducer. These differences can produce errors in estimation of gestational age as large as ten weeks.

Sonography of post-cesarean-section bladder-flap hematoma

A bladder-flap hematoma is an unusual complication of a lower-uterine transverse cesarean section. As a result of bleeding at the incision site, a hematoma forms between the bladder and lower uterine segment. The clinical, sonographic, and surgical findings in seven patients with this complication are described. In all, sonography showed a solid or complex mass of varying sizes interposed between the posterior bladder wall and the anterior uterine wall. Differentiation of a hematoma from an infected hematoma/abscess can be difficult, but the presence of air in the mass strongly suggests the latter. Sonography can detect this complication easily and accurately, and therefore significantly focus and guide therapy.