Cortical visual impairment caused by twin pregnancy.

PURPOSE: To report a possible relationship between twin pregnancy and cortical visual impairment. METHODS: Three children who had been the products of twin pregnancies were identified as having cortical visual impairment. One child (Patient 2), a dizygotic twin, developed cortical visual impairment after a preterm birth. Two children (Patients 1 and 3), the products of monochorionic pregnancies, developed cortical visual impairment. All children were examined ophthalmologically and neurologically. RESULTS: An evaluation of the gestations of these children indicates that twin pregnancy per se was probably etiologic in the development of cortical visual impairment. In Patient 2, twin pregnancy probably caused preterm birth and resulting cortical visual impairment. In Patients 1 and 3, twin-to-twin transfusion syndrome was the cause of cortical visual impairment. In Patient 1, fetal demise precipitated an acute twin-to-twin transfusion syndrome. CONCLUSIONS: Children who show cortical visual impairment at or shortly after birth should be evaluated for the possibility of twin pregnancy. Twin pregnancy increases the risk of neurologic damage, including damage to the visual cortex, to optic radiations, or both.

Uptake of indium-111-labeled leukocytes by brain metastasis.

Uptake of indium-labeled leukocytes was seen in two cases of histologically proven brain metastasis. In one, this led to misdiagnosis of the lesion as an abscess. On histological evaluation, a large number of white blood cells or macrophages was seen at the neoplastic sites. Reasons for leukocyte accumulation around metastatic brain neoplasms are discussed. In contrast to the current reports that indium-labeled leukocyte scans can differentiate intracranial infection from tumor, these cases demonstrate their lack of specificity in the detection of brain abscess.

Ultrasound imaging as a screening study for malignant soft-tissue tumors.

Fifty patients who had a palpable soft-tissue mass and an apparently normal radiograph were studied with ultrasound imaging before excision or biopsy of the lesion was done. As shown by the sonograms, thirty-five lesions had a discrete echo pattern (usually reduced echoes and a clearly defined lesional margin) and fifteen had an ill defined pattern (similar to the pattern of the surrounding normal tissues with no definable lesional margin). Fourteen lesions were malignant and thirty-six, benign. The sonograms of all fourteen malignant lesions showed a discrete pattern, while the sonograms of the benign ones showed twenty-one discrete and fifteen ill defined patterns. Therefore, the malignant lesions produced a discrete pattern in every instance, and every lesion that produced an ill defined pattern was benign. Fourteen of the fifty lesions were cystic; of these, thirteen were benign and one was malignant. The sonograms correctly identified the cyst in seven of the thirteen benign lesions and in the one malignant cystic lesion. Based on these findings, we concluded that all palpable soft-tissue masses that appear to be discrete on a sonogram should be diagnosed without delay by examination of a specimen taken at biopsy, whereas lesions that have an ill defined appearance on a sonogram may be assumed to be benign and may safely be observed in selected patients.

CT of emphysematous gastritis.

Emphysematous gastritis is a serious, often fatal condition. It is the result of destruction of the mucosal membrane with subsequent bacterial invasion of the stomach. We have encountered two cases at CT. Recognition is important since early intervention may be lifesaving.

Prenatal diagnosis of central nervous system abnormalities.

Fetal anomalies have been the subject of innumerable publications both in the prenatal and neonatal literature. This has significantly increased in the last 10 years, mainly because of the advent of high-resolution ultrasound equipment and improvement of scanning techniques. In addition, guidelines issued by professional organizations involved in prenatal diagnosis have encouraged a more universal approach to the imaging and documentation of prenatal findings. The fetal central nervous system is the most frequently investigated organ system, mainly because of its easy accessibility and prominence even in the early stages of embryologic development. The biparietal diameter was the first fetal measurement to be widely used in determining gestational age. As investigators gained more experience, the appearance of ultrasound images achieved the resolution that allows direct comparisons with gross specimens and more recent sophisticated techniques of computed tomography and magnetic resonance imaging. Now endovaginal ultrasound can document early first trimester development and compare it to known embryologic landmarks. Interest in demonstrating the ultrasound counterpart of central nervous system structures in the early stages of development has resulted in a plethora of articles proving the unique ability of ultrasound in imaging the developing fetus. In view of all these developments, the beginning ultrasound specialist is faced with the challenge and responsibility not only of being familiar with the literature but also of the mastery of scanning techniques that allow accurate prenatal diagnosis. It is therefore helpful to review key developmental milestones in embryologic life and correlate them with the corresponding prenatal ultrasound appearance. In addition, the changing appearance of the developing fetus has created a need for a systematic approach in the evaluation of structures so routine protocols can be established. This has been the subject of other publications that allow the novice to draw from the cumulative experience of different centers around the world. It is important to pay attention to the specifics described in the literature when duplicating results in one's laboratory. The frustration of not being able to reproduce results is common, especially when technical limitations prevent imaging under ideal conditions. This is especially true in patients who are first seen in the later third trimester with no prior prenatal care.(ABSTRACT TRUNCATED AT 400 WORDS)

Prenatal diagnosis of complicated abdominal wall defects.

The accurate prenatal diagnosis of anterior abdominal wall defects is important because it affects patient management and prognosis. The pathophysiology of each defect leads to key characteristics that make it possible to differentiate one entity from another. Among these features are the location of the defect in relation to cord insertion, the size and contents of the defect, and the associated anomalies. This article reviews the underlying defects, the characteristic ultrasound findings, the associated anomalies, and the prognosis of simple and complicated abdominal wall defects. The basic features of simple abdominal wall defects (i.e., omphalocele and gastroschisis) were used as the initial points of assessment. A comparison of the different features of these abnormalities and how they differ from one another resulted in the development of criteria that facilitated the understanding of the different ultrasound manifestations of these anomalies.

Effect of manganese on human placental spin-lattice (T1) and spin-spin (T2) relaxation times.

Human placentas were obtained immediately following delivery and incubated with manganese chloride (MnCl2) in concentrations ranging from 0.002 to 2.0 mM. Proton density, T1 and T2 were measured at times ranging from 5-200 minutes. There was rapid uptake of manganese by the placenta producing a dose-dependent decrease in placental T1 and T2. The major effect of manganese uptake was shortening of T1 suggesting that the contrast between placenta and myometrium will be enhanced predominantly for T1-dependent imaging pulse sequences.

Impaired white matter development in extremely low-birth-weight infants with previous brain hemorrhage.

BACKGROUND AND PURPOSE: Brain hemorrhage is common in premature infants. The purpose of the study is to evaluate white matter development in extremely low-birth-weight infants with or without previous brain hemorrhage. MATERIALS AND METHODS: Thirty-three extremely low-birth-weight infants were prospectively enrolled and included in this institutional review board-approved study. Another 10 healthy term infants were included as controls. The medical records of the extremely low-birth-weight infants were reviewed for sonography diagnosis of intraventricular hemorrhage. All infants had an MR imaging examination at term-equivalent age for detection of previous hemorrhage, and their white matter was scored and compared among different groups. DTI measured fractional anisotropy values were also compared voxelwise by tract-based spatial statistics. RESULTS: Compared with controls, the white matter score was not significantly different in extremely low-birth-weight infants without blood deposition on MR imaging (P = .17), but was significantly worse in extremely low-birth-weight infants with blood deposition on MR imaging but no intraventricular hemorrhage diagnosis by sonography (P = .02), in extremely low-birth-weight infants with grade 1 or 2 intraventricular hemorrhage on sonography (P = .003), and in extremely low-birth-weight infants with grade 3 or 4 intraventricular hemorrhage on sonography (P = .0001). Extremely low-birth-weight infants without blood deposition on MR imaging did not show any white matter regions with significantly lower fractional anisotropy values than controls. Extremely low-birth-weight infants with blood deposition on MR imaging, but no intraventricular hemorrhage diagnosis, did show white matter regions with significantly lower fractional anisotropy values, and extremely low-birth-weight infants with intraventricular hemorrhage diagnosis had widespread white matter regions with lower fractional anisotropy values. CONCLUSIONS: Previous brain hemorrhage is associated with abnormal white matter in extremely low-birth-weight infants at term-equivalent age, and sonography is not sensitive to minor hemorrhages that are sufficient to cause white matter injury.

Prenatal detection of anterior abdominal wall defects with US.

The size and position of an anterior abdominal wall defect, its contents, and its association with other anomalies are features that can be diagnosed in utero with ultrasound and that allow a differential diagnosis to be made. The correct prenatal diagnosis is extremely important for patient management. The key feature for sonographically distinguishing these conditions is the position of the defect in relation to the umbilical cord insertion. Omphaloceles and pentalogy of Cantrell usually involve a midline defect at the umbilical cord insertion. Gastroschisis most frequently consists of a small, right-sided paraumbilical defect. Eccentric, large lateral defects are typically present in limb-body wall complex or amniotic band syndrome. Bladder and cloacal exstrophy involve the infraumbilical region. In addition, the size of the defect, the organs eviscerated, the presence of membranes or bands, and any associated abnormalities help determine the correct diagnosis. Increased knowledge of these uncommon fetal conditions should result in better detection, more accurate diagnosis, and improved management of anterior abdominal wall defects.

Incidental hydronephrosis on bone scintigraphy: sonographic verification.

We studied 98 kidneys in 55 patients with bone scintiscans and renal sonography. Among the 29 kidneys in which hydronephrosis was suspected on bone scintiscans only 12 were truly hydronephrotic by renal ultrasound. In the other 17 cases extrarenal pelves, postural stasis, early urinary tract obstruction or renal parenchymal disease may have contributed to the discrepant findings. By ultrasound criteria there were no false negative readings for hydronephrosis on scintiscan. While it is safe to interpret absence of hydronephrosis caution should be used in diagnosing hydronephrosis, since less than half of the cases actually will have the disease when suspected on a bone scintiscan.

Ultrasound evaluation of abdominal pregnancy.

The ultrasound diagnosis of abdominal pregnancy continues to be difficult in spite of recent advances in ultrasound technology. The principal impediment is a low suspicion for the diagnosis because of its relatively asymptomatic nature and the lack of specificity of symptoms when present. In the early days of sonography when static B-mode scanning was used, a "gestalt" diagnosis was suggested, based on one's ability to have an overall perspective of the intrauterine contents. With conversion to exclusive real time imaging and the inherent limitation of the field of view, this "gestalt perception" is no longer possible. It is therefore necessary to reassess our criteria based on this change and determine those that remain reliable for diagnosis.

Gestational trophoblastic disease: a spectrum of radiologic diagnosis.

Gestational trophoblastic disease (GTD) encompasses a broad spectrum of conditions that includes hydatidiform mole, invasive mole, and choriocarcinoma. Although ultrasound (US) is the examination of choice for initial diagnosis, plain radiography, angiography, computed tomography (CT), and magnetic resonance (MR) imaging all play a role in determining the presence of GTD and the extent of its complications. US shows molar gestations as alternating cystic and solid tissue that fills the entire uterus. CT and MR imaging are useful in detecting myometrial invasion, parametrial extension, and metastasis. Because each imaging technique offers a unique perspective highlighting different aspects of GTD, it is important to understand the pathophysiology and natural history of the disease. Such knowledge in turn leads to a greater understanding of the spectrum of findings seen on various kinds of radiologic images and enables the radiologist to play an important role in directing patient work-up by recognizing the implications of various findings and guiding management decisions.

The utility of urgent colonoscopy in the evaluation of acute lower gastrointestinal tract bleeding: a 2-year experience from a single center.

OBJECTIVE: Urgent colonoscopy is often recommended to evaluate acute rectal bleeding. However, it may not identify a source because of blood in the lumen or inadequate preparation. Our aim was to determine the utility of urgent colonoscopy as the initial test for acute rectal bleeding. METHODS: This was a retrospective chart review of all patients discharged in 1997 and 1998 with an International Classification of Diseases, 9th Revision, code for hematochezia or rectal bleeding. RESULTS: We identified 514 charts but excluded 424 because of inaccurate coding. In the 90 with confirmed acute rectal bleeding, colonoscopy was the initial test in 39; age, sex, and race distributions were similar to those who did not have colonoscopy. A definite source of bleeding was seen at colonoscopy in only three patients, a probable source in 26, and no source in 10. Therapeutic intervention in four patients with a definite or probable source was successful in three. The commonest reasons for not performing urgent colonoscopy were bleeding from presumed hemorrhoids or bleeding that was clinically insignificant. Spontaneous resolution of bleeding and length of hospital stay were not affected by urgent colonoscopy. Five patients had surgery for unrelated reasons. In-hospital mortality was 2% and was unrelated to bleeding. CONCLUSION: Urgent colonoscopy as the initial investigation in acute lower GI tract bleeding probably does not alter the outcome in most cases. Identification of a definite bleeding source leading to successful therapeutic intervention is rare. Spontaneous resolution is frequent, length of hospital stay is similar, and clinical outcome is excellent regardless of whether or not urgent colonoscopy is performed.

Fetal teratomas: antenatal diagnosis and clinical management.

Four cases of fetal teratomas arising from the sacrococcygeal and oropharyngeal areas are reported. The diagnosis, method of management, and grade of tumor are compared with previous experience in the literature. Pharyngeal lesions carry a worse prognosis for survival compared to the more common sacrococcygeal type (SCT). Atraumatic delivery and early repair of the lesion contribute to prolonged survival and lack of complications in cases of sacrococcygeal teratomas.

Differing attitudes toward virtual and conventional colonoscopy for colorectal cancer screening: surveys among primary care physicians and potential patients.

OBJECTIVES: To investigate attitudes among primary care physicians and potential patients concerning "virtual" and conventional colonoscopy for colorectal cancer screening. METHODS: We sent 1000 questionnaires to primary care physicians by electronic or postal mail and administered 400 to potential patients. Questionnaires contained progressively detailed information about the tests and asked for choices based on information presented. RESULTS: One hundred eight-eight primary care physicians and 323 potential patients were included. Results indicated the following: 76.6% of potential patients and 47.3% of physicians initially preferred virtual colonoscopy because of its noninvasive nature; 23.6% of potential patients and 52.9% of physicians valued the ability of conventional colonoscopy to visualize the mucosa directly; and 67.4% of potential patients and 51.6% of physicians preferred virtual colonoscopy because it does not require sedation. Considering all information, most potential patients preferred virtual to conventional colonoscopy (60.2% vs 25.7%), whereas more physicians preferred conventional to virtual colonoscopy (44.9% vs 30.3%). Additionally, 82.3% of potential patients would comply more with recommendations for colorectal cancer screening, and 61.7% of physicians would refer more patients for screening, if virtual colonoscopy was available. CONCLUSIONS: Potential patients preferred virtual to conventional colonoscopy, whereas physicians favored conventional colonoscopy. Physicians placed more importance on the ability of conventional colonoscopy to visualize the mucosa directly, the opportunity for therapy, and cost. Potential patients were more encouraged than physicians by the availability of virtual colonoscopy for improving participation in colorectal cancer screening.

MR imaging in high-risk obstetric patients: a valuable complement to US.

The accuracy of prenatal diagnosis has become increasingly critical in the field of high-risk obstetrics. Although ultrasound (US) provides adequate information in most cases and continues to be the initial prenatal examination of choice, there are instances in which the results of the US study may be equivocal. The role of magnetic resonance (MR) imaging was explored in 27 selected patients with various indications to determine its effectiveness as a complement to US. MR imaging was most helpful in the diagnosis of extrauterine gestation, evaluation of placental position, determination of extent or nature of masses associated with pregnancy, and differentiation between diaphragmatic hernia and a thoracic mass. Although MR imaging did not add information that affected the accuracy of the diagnosis of oligohydramnios, in all other cases it provided an extra dimension in diagnosis by showing clearer anatomic relationships in the pelvis. It has proved to be a valuable complement to an equivocal US study.

Inferior vena caval filters: noninvasive evaluation.

Transvenous inferior vena caval filters were placed in 32 patients (21 bird's nest [BN] and 11 Kimray-Greenfield [K-G] filters). Positive contrast cavography was performed before and immediately after filter placement as well as during long-term follow-up studies. In 23 patients, computed tomographic (CT) scanning was also performed; in 10 patients, real-time ultrasound (US) study was used as an adjunct. CT scans of the BN filter showed one case of hemorrhage and one case of air embolism, both of which were not recognized at cavography. CT scanning of the K-G filter demonstrated two cases of deep penetration of the prongs and one large retroperitoneal hematoma. Real-time US scanning played a major role in checking the final position of the filter and in determining its stability during repositioning of the upper prongs of one BN filter. Noninvasive examinations, including CT and US scanning, are valuable adjuncts in immediate and long-term follow-up study of patients with inferior vena caval filters.

CT findings in abdominal actinomycosis.

The diagnosis of abdominal actinomycosis is difficult because of its relative infrequency and imitation of other diseases. We present four cases in which these difficulties in diagnosis were experienced and show the utility of CT in suggesting this disease. Aspiration, biopsy, and proper culture technique, in conjunction with typical CT findings of transfascial and multiple organ involvement, led to the proper diagnosis in all cases.