Lumbosacral agenesis: clinical characteristics, imaging, and embryogenesis.

We report 5 cases of complete, or nearly complete, agenesis of the lumbar and sacral spine. In 1 case pregnancy was terminated at 23 weeks of gestation, and the others were livebirths. The surviving 4 patients were all infants of diabetic mothers. Imperforate anus was present in 2 of 4 liveborn patients and was suspected in the abortus. All liveborn cases were paraplegic, and all exhibited the 'Buddha' deformity of the lower extremities. One patient had congenital obstructive hydrocephalus, probably representing a variant of holoprosencephaly, requiring a ventriculoperitoneal shunt. No other nervous system anomaly was identified in any patient, and the other patients are showing normal cognitive development. We propose that these patients have defects which occurred during germ cell formation (i.e., during gastrulation), with interruption of the primitive streak resulting in combined failure of primary and secondary neurulation.

Radiologic evaluation of the intravenous oxygenator.

This report describes the radiologic appearance of the intravenous oxygenator (IVOX), an intracorporeal CO2-O2 exchanger for use in patients with severe respiratory deficiency, and the extensive radiographic and sonographic support required for its use. Six patients aged 19-39 years who had severe adult respiratory distress syndrome (ARDS) and who were not expected to survive were selected for IVOX placement; ARDS was caused by trauma (four patients), severe pneumonia (one patient), or a fat embolus from a tibial fracture (one patient). Before insertion of the IVOX, all patients underwent evaluation of their right internal jugular vein, right common femoral vein, and inferior vena cava with real-time ultrasound (US) to ascertain vascular size. The IVOX improved oxygenation in all patients; because of such improvement, one patient survived. Use of the IVOX may become common; hence, radiologists should understand how the IVOX functions and its appropriate placement, be able to identify it on chest and abdominal radiographs, and appreciate the importance of US in placement of this device and follow-up.

Reverberation reduction in ultrasonic B-mode images via dual frequency image subtraction.

The authors demonstrate the feasibility of an approach, dual-frequency subtraction imaging, for suppressing artifacts produced by reverberation of strong echoes among specular reflectors. This method is based upon the principle that specularly reflected echoes from flat boundaries are frequency-independent whereas the diffusely scattered echoes from small scatterers are frequency-dependent. The approach was assessed on phantoms including one consisting of two parallel plastic plates between layers of foam sponges using a prototype experimental system. Preliminary results show that this method is superior to simple thresholding techniques or signal compression and holds great promise for suppressing reverberation artifacts in ultrasonic images.

Clinical trials of an intravenous oxygenator in patients with adult respiratory distress syndrome.

In patients with severe adult respiratory distress syndrome, mechanical ventilation may not be able to ensure gas exchange sufficient to sustain life. We report the use of an intravenous oxygenator (IVOX) in five patients who were suffering from severe adult respiratory distress syndrome as a result of aspiration, fat embolism, or pneumonia. IVOX was used in an attempt to provide supplemental transfer of CO2 and O2 and thereby reduce O2 toxicity and barotrauma. All patients were tracheally intubated, sedated, and chemically paralyzed and had a PaO2 < 60 mmHg when the lungs were ventilated with an FIO2 = 1.0 and a positive end expiratory pressure of > or = 5 cmH2O. The right common femoral vein was located surgically, and the patient was systemically anticoagulated with heparin. A hollow introducer tube was inserted into the right common femoral vein, and the furled IVOX was passed into the inferior vena cava and advanced until the tip was in the lower portion of the superior vena cava. IVOX use ranged from 2 h to 4 days. In this group of patients, IVOX gas exchange ranged from 21 to 87 ml x min-1 of CO2 and from 28 to 85 ml x min-1 of O2. One of the five patients survived and was discharged from the hospital. The IVOX transferred up to 28% of metabolic gas-exchange requirements. One patient with a small vena cava showed signs of caval obstruction. Three other patients demonstrated signs of a septic syndrome after the device was inserted.(ABSTRACT TRUNCATED AT 250 WORDS)

Imaging of gallbladder variants.

A wide range of normal gallbladder variations are seen on gallbladder imaging. This essay illustrates the major variations that may be encountered, including anomalies in location, number, and form.

The efficacy of transrectal ultrasound and prostate cancer.

An increased interest in the diagnosis and treatment of prostate cancer, particularly in the last few years, is reflected in the literature. Numerous articles have been published since 1980 on the subject of imaging of the prostate gland. This article is a review of transrectal ultrasound and its efficacy in the diagnosis and treatment of prostate cancer. Included is a review of the normal prostate anatomy, typical and atypical sonographic features, clinical and radiographic staging of prostate cancer, efficacy of the digital rectal examination, role of ultrasound in prostate cancer screening, surgical treatment, and radiotherapy of prostate cancer.

Prenatal detection of Roberts-SC phocomelia syndrome: report of 2 sibs with characteristic manifestations.

We describe 2 sibs with Roberts-SC phocomelia syndrome. Although an ultrasound scan performed at 13 weeks of gestation failed to identify specific abnormalities, repeat scan at 17 weeks detected tetraphocomelia. Ultrasonography can reliably detect Roberts-SC phocomelia prenatally; however, serial scans may be needed. Postmortem examination of the proposita confirmed the sonographic findings and also disclosed dysplastic kidneys and ovarian dysgenesis. The degree of phenotypic variation observed between the sibs supports the hypothesis that Roberts syndrome and SC phocomelia represent a single genetic entity.

Transabdominal and transvaginal endosonography: evaluation of the cervix and lower uterine segment in pregnancy.

The clinical value of conventional transabdominal and transvaginal sonography (endosonography) for the evaluation of the cervix and lower uterine segment between 14 and 36 weeks' gestation was evaluated in 20 unselected obstetric patients. Sonographic evaluation of the cervix and lower uterine segment was adequately depicted in 76% with the transabdominal technique compared to 83% with the transvaginal approach. According to set guidelines, these preliminary results suggest that the transvaginal technique may be superior in obtaining an adequate evaluation of the lower uterine segment and cervix and may offer an advantage of not depending on a fully distended bladder for evaluation.

Advanced abdominal pregnancy associated with fetal pulmonary hypoplasia: report of a case.

Delaying delivery of a premature abdominal pregnancy may allow for fetal pulmonary maturation. Prolonged extreme oligohydramnios, however, resulting in significant pulmonary hypoplasia would frustrate any effort to wait for pulmonary maturation. Little mention of this complication is found in the literature. Therefore, two cases of abdominal pregnancy are presented, one with fetal pulmonary hypoplasia and one without. Assessing the volume of amniotic fluid is suggested when a decision is being made to deliver this type of pregnancy.

Prenatal detection of fetal anomalies with sonography.

This article has presented an overview of the sonographic detection of fetal anomalies. Fortunately, fetal anomalies are relatively rare, but the information that is obtained with sonography can facilitate obstetric management and counseling of the expectant parents.

Breast sonotomography and high-frequency, hand-held, real-time sonography: a clinical comparison.

The diagnostic quality of breast sonography as performed with a dedicated tomographic unit (ST) and a hand-held, high-frequency, real-time transducer (RT) was evaluated in 76 patients. In 38 per cent of cases, ST was found to be of equal diagnostic quality to RT. The number of instances in which ST was judged to be better than RT was slightly greater than those in which RT was considered better than ST (34 vs. 24 per cent) (P less than or equal to 0.10). In 3 per cent of cases, the diagnostic quality of both ST or RT was considered to be poor. The majority of instances when the diagnostic quality of ST was judged to be better than RT occurred in establishing a negative diagnosis, whereas RT seemed to have greater diagnostic quality than ST in the evaluation of a palpable mass.

Management of aortic thrombosis secondary to umbilical artery catheters in neonates.

During the past ten years, we have surgically managed seven neonates who developed total occlusion of the distal aorta due to umbilical artery catheters. All patients experienced symptoms of congestive heart failure. Five patients presented with severe hypertension, and all of these had aortorenal involvement: three infants had aortorenal thrombosis and two infants had infrarenal aortoiliac thrombosis with suprarenal extension of thrombus. Two infants had aortoiliac thrombosis with clot confined to the infrarenal aorta. Aortic thrombosis imposes an additional severe hemodynamic insult in these already seriously ill infants. Survival in this group of patients depends upon prompt recognition of this problem, effective surgical correction, and careful perioperative management. Our experience suggests that this diagnosis should be entertained in the infant presenting suddenly with congestive heart failure, hypertension, or lower limb ischemia after umbilical artery catheterization. The diagnosis is preferably confirmed by real-time ultrasound and/or radionuclide flow scan, although aortography may sometimes be necessary. Surgical management includes early transabdominal aortotomy with thrombectomy. Prompt thrombectomy resulted in the survival of six patients. One infant died in acute renal failure. Renal function and leg perfusion is satisfactory in the remaining patients, although one child required later operative correction of renovascular hypertension. Two additional patients needed prolonged postoperative antihypertensive therapy for 14 to 34 months before this problem resolved. Long-term follow-up is necessary for managing renovascular hypertension and monitoring lower extremity perfusion.

Uterine adnexal torsion: sonographic findings.

Acute torsion of the uterine adnexal structures (ovary and fallopian tube) is a recognized surgical emergency, but rarely has the diagnosis been made preoperatively on the basis of imaging studies. This report describes 16 cases in which the diagnosis was suggested preoperatively on the basis of sonography and subsequently confirmed at surgery. In all of the patients studied, a pelvic or pelvoabdominal mass was present on sonography. These masses had a sonographic texture ranging from cystic to solid, depending on the presence and extent of internal hemorrhage and/or stromal edema. In the majority of patients (13 of 16), adnexal torsion was associated with a preexisting cystic adnexal mass. Eight of these had thin internal septae. The severity of symptoms was variable and did not correlate directly with the sonographic features of the pelvic mass. Consideration of this entity in the proper clinical setting and with the typical sonographic findings will facilitate prospective recognition of adnexal torsion, thereby improving the chances for salvage of the involved adnexal structures.

Separated chorioamnion and elevated chorion: sonographic features and clinical significance.

The clinical presentation and outcome of pregnancy was analyzed in thirteen patients in whom a free-floating intrauterine membrane was found on sonography. The cases were divided into two groups: those with elevated chorion and those with chorioamniotic separation. Five of seven patients with chorioamniotic separation progressed normally to term and delivered normal infants. In the two pregnancies with chorioamniotic separation that did not progress to term, one was associated with a placental chorioangioma and the other had a dead fetus that had a cystic hygroma indicative of Turner's syndrome. Of the six patients with elevated chorion, all presented with an episode of vaginal bleeding in the early second trimester. Five of six patients with elevated chorion progressed to term with the delivery of normal infants. One patient with extensive elevation of the chorion aborted. Three patients with elevated chorion had a subchorionic clot, whereas this was not present in patients with separated chorioamnion. Follow-up sonographic examination of patients with separated chorioamnion and elevated chorion revealed that most (11 of 13), but not all pregnancies in which an intrauterine membrane was found progressed to term without complications.

Sonographic depiction of endometrial changes occurring with ovulation induction.

Endometrial thickness and texture were evaluated with serial pelvic sonograms in ten normal, menstruating women and 107 patients undergoing ovulation induction for in vitro fertilization. Serial sonograms were performed in the control group every other day throughout the menstrual cycle, whereas the sonographic examinations of the ovulation induction patients were performed daily in a four- to eight-day time interval after their medications were completed and prior to laparoscopy for follicular aspiration. Endometrial thickness increased (defined as a persistent change greater than or equal to 1 mm) in 21 of 53 women (40 percent) who received human menopausal gonadotropin (HMG). Of the 54 women treated with clomiphene citrate (CC), five of 12 (42 percent) at 50 mg daily, 13 of 33 (39 percent) at 100 mg daily, and one of nine (11 percent) at 150 mg daily were found to have endometrial thickening. Although the frequencies of endometrial thickening in the high-dose CC and HMG groups were not significantly different (P = 0.09), the peak estradiol (E2) levels in the CC (150 mg) group (E2 = 944 +/- 165 pg/ml) were significantly higher (P less than 0.001) than those in the HMG group (E2 = 584 +/- 26 pg/ml). The relatively low frequency of endometrial thickening in women receiving CC (150 mg) despite very high E2 levels, and the decreased incidence of endometrial thickening relative to increasing dosages of CC may reflect an antiestrogenic effect of CC on the endometrium. In those patients undergoing ovulation induction, the texture of the endometrium remained the same in 98 cycles and changed during nine.(ABSTRACT TRUNCATED AT 250 WORDS)

Estimation of ultrasonic attenuation and mean backscatterer size via digital signal processing.

The backscattered rf signals from the lungs of fetal sheep during their last trimester of development were digitized and processed in an attempt to correlate ultrasonic parameters with measured functional parameters related to lung maturation. The broadband, post- TGC , rf signal of a commercial B-mode ultrasonic scanner was digitized at a sampling rate of 25 MHz. Sorting excluded data from regions of rib shadowing and other nonlung structures from analysis. The sorted data were used to estimate the slope of the ultrasonic attenuation coefficient with respect to frequency via linear regression on the average difference of the logarithm of power spectra from separated data segments. The power spectra were also corrected for attenuation, averaged and used to compute the power cepstrum of the backscattered signal which can be related to mean backscatterer radius. Results are presented for eight fetal sheep.