High-resolution Ultrasound Scanning Research Articles

Determination of intervillous flow in early pregnancy

The process of placentation in the macaque has been extensively studied and found to resemble closely that observed in the human. In this model, histopathologically, intervillous flow is anticipated from week 3 post-conception. We set out to document the nature and onset of intervillous flow in the macaque in vivo using colour Doppler imaging (CDI), colour Doppler energy (CDE) and pulsed-wave Doppler (PWD). Pregnant females were assessed between 15-50 days gestation (term = 165 days) with an Acuson 128/XP10 high-resolution ultrasound scanner, using a 7-MHz linear array probe. The placenta, subjacent decidua and myometrium were assessed using CDI and CDE. Specific regions of flow were interrogated using PWD; the resulting flow velocity waveforms were stored and quantified using conventional Doppler indices. B-mode sonography was able to demonstrate the well-defined placental-decidual interface observed in this species; CDI and CDE clearly visualized the uteroplacental vasculature. Spiral arteries were followed to their point of discharge into the intervillous space, and PWD at these sites obtained a characteristic flow velocity waveform. The indices obtained confirmed a flow of low resistance and pulsatility throughout the gestation studied. Flow within the intervillous space was noted from day 20 of gestation.

Ultrasonography in the diagnosis of Morton's neuroma

High resolution ultrasound scanning of the plantar surface of the foot was performed on 60 patients with symptoms suggesting Morton's neuroma. Sixty-four feet underwent ultrasound examination prior to surgery and 70 intermetatarsal clefts were reported on. The clinical outcome in 15feet with normal scans is unknown, since they remain unoperated. Of the remaining 51 clefts reported positive for a neuroma, 48 were subsequently shown by surgical exploration and histological analysis to have had a correct scan (87.3% accurate). There were three false-positive scas (5.4%) and four false-negative scans (7.3%). The combined incidence of incorrect scans was therefore 12.7%. The authors conclude that ultrasonography may prove to be a promising screening tool in the investigation of patients with metatarsalgia provided the scans are undertaken by an experienced operator using modern equipment with good resolution.

Book reviews

Neonatal medicine has long since been satisfied merely with assessing outcome in terms of survival, and is increasingly concerned with the quality of that survival in neurodevelopmental terms, 2, 10 and more years later. Perinatal cerebral injury has been demonstrated using CT scanning for two decades, but due to ease and convenience has been largely supplanted by high resolution ultrasound scanning in the neonatal penod The simplicity of the technique has enabled its rapid spread into use in neonatal intensive care units the world over. Although dozens of publications in journals and books have testified to the interest in diagnosing cerebral haemorrhage and infarction in sick preterm infants, most report small and often biased populations of preterm infants, and a wide variety of techniques to discuss them.

Sequential penile ultrasound monitoring of patients treated with chronic intracavernous prostaglandin e 1

Objectives Clinical outcome studies of prostaglandin E 1 (PGE 1) have shown a markedly decreased rate of palpable fibrosis and plaque formation. In this prospective study we investigate the potential of this agent to produce subclinical fibrotic changes. Methods Real-time high-resolution ultrasound scanning of the corpora was performed using a 7.5 to 10 MHz linear array transducer in 80 men on initiation of treatment with self-administered PGE 1 and at quarterly intervals during the course of follow-up (3 to 28 months). The dorsal portion of the penile shaft was scanned in the transverse and sagittal planes from base to glans for a side by side comparison of the cavernosal tissue, evaluating local abnormalities of tissue echogenicity. Results Palpable lesions were not detected in any men on quarterly follow-up examination. Thirteen (16.5%) men developed new echogenic foci not present on pretreatment scanning at the following locations: proximal corpus cavernosum, subcutaneous tissues, and corpus spongiosum. These changes were observed both as single and multiple lesions ranging in size from 1 to 10 mm. The presence of these findings was independent of the etiology of impotence, dose frequency, and duration of intracavernous therapy. Conclusions The significance of these subclinical changes is unknown but their low incidence should be recognized when considering long-term intracavernous therapy.

An 85 mW, 10 b, 40 Msample/s CMOS parallel-pipelined ADC

The design of a low-power 10 b, 40 Msample/s ADC integrated in a 0.8 /spl mu/m multithreshold CMOS process is presented. The fully differential design employs parallel-pipelined ADC each using a combination of single- and multibit-per-stage pipelined architectures. The ADC, targeted for high-resolution video terminals and ultrasound scanning applications, achieves a nonlinearity-plus-quantization-error of /spl plusmn/1 LSB at 10 b, dissipates 85 mW from a single 2.7 V supply, and occupies an area of 1.9 mm by 2.1 mm. >

Treatment of acute anterior myocardial infarction with zofenopril

Microal buminuria has been associated with a cluster of metabolic and nonmetabolic risk factors, suggesting that it might indicate the presence of generalized microvascular damage in patients with essential hypertension. To explore whether microalbuminuria is associated with early target organ damage, two groups of essential hypertensive patients, with (n = 17) (HtAlb+) and without (n = 16) (HtAlb−) microalbuminuria, and a control group (C) of healthy normotensive subjects (n = 20) were studied. The study groups, selected among participants of a large epidemiologic trial, were carefully matched for several potentially confounding variables such as gender, age, duration of hypertension, and body mass index. Albumin excretion rate was evaluated by radioimmunoassay in three nonconsecutive timed overnight collections after 3 weeks of pharmacologic wash-out. Left ventricular mass was assessed by M-B-mode echocardiography, carotid wall thickness by a high resolution ultrasound scan, and renal vascular impedance by Doppler scan. Office as well as 24-h ambulatory pressure monitoring (Takeda TM-2420) were also evaluated. There was no difference between the two hypertensive groups for office and 24-h blood pressure levels except for a lower daytime/nighttime systolic blood pressure ratio in the group with microalbuminuria. Microalbuminuric patients showed signs of early organ damage as compared to normoalbuminuric patients and normal subjects, namely greater left ventricular mass indices (LVMI 167 ± 7 g/m2 in HtAlb+; 139 ± 9 g/m2 in HtAlb−; 118 ± 5 g/m2 in C, P < .001) and increased wall thickness of common carotid arteries (intima plus media thickness 12.5 ± 0.2 mm in HtAlb+; 11.7 ± 0.3 mm in HtAlb−; 11.2 ± 0.2 mm in C, P < .001) as well as higher intrarenal vascular resistance (mean resistive index 0.62 ± 0.01 in HtAlb+; 0.59 ± 0.01 in HtAlb−; 0.59 ± 0.01 in C, P < .05). In conclusion, microalbuminuria is an early marker of diffuse target organ damage in essential hypertension and therefore can be useful to identify patients for whom more aggressive preventive strategies or additional treatment measures are advisable.

Ultrasonographic appearance of external callus in long-bone fractures

High-resolution real-time ultrasound (US) scanning was used to monitor serially 24 patients with an acute long-bone fracture and three patients with humeral non-union, looking at the fracture site over a period of 12 months following the fracture. In both these groups, we found that US gave important information about the soft tissues surrounding the fracture site, and indicated callus formation at an early stage. US was more sensitive than conventional radiography at showing the early phases of organization of the callus, and its progression to bridging new bone formation. US also clearly showed a disorganized echopattern at the fracture site of the patients with non-union.

A prospective study of the prevalence of clear‐cut endocrine disorders and polycystic ovaries in 350 patients presenting with hirsutism or androgenic alopecia

To determine the frequency of polycystic ovaries (PCO) on ultrasound and the incidence of clearcut endocrine disorders leading to virilization in patients complaining of hirsutism or androgenic alopecia. The major purpose was to determine a coherent policy for the routine biochemical assessment of such women. A prospective study of women attending a joint skin/endocrine clinic complaining of these problems. Three hundred and fifty consecutive women with hirsutism and/or androgenic alopecia were assessed. Baseline endocrine screens were conducted on two occasions and included measurement of serum testosterone, androstenedione, dehydroepiandrosterone sulphate, sex hormone binding globulin, LH, FSH, 17-hydroxyprogesterone and PRL. The ovaries were visualized by high-resolution pelvic ultrasound scanning. Eight women were identified with relevant endocrine disorders; of these, one was acromegalic and one had a microprolactinoma--in both cases the association may have been fortuitous. Three had clear-cut 21-hydroxylase deficiency, one a rare hepatic enzyme deficiency (11-reductase), one a virilizing adrenal carcinoma and one a Leydig cell tumour. The latter six cases all had persistently elevated levels of serum testosterone (> 5 nmol/l). In all, 13 women had baseline testosterone levels in excess of 5 nmol/l. Polycystic ovaries were present in 81% of the cases who had erratic cycles and 52% of those with regular cycles; PCO were present in two of the women with 21-hydroxylase deficiency and in the woman with 11-oxoreductase deficiency. The Leydig cell tumour (1.2 cm diameter) was not detected on ultrasound or CT scan. For the exclusion of enzyme deficiencies and virilizing tumours clinical assessment and a single serum testosterone measurement will suffice.

Long-term follow-up studies on iodine-131 treatment of hyperthyroid Graves' disease based on the measurement of thyroid volume by ultrasonography.

In the present series of studies, the long-term (four year) effect of 80 Gy of 131I treatment was evaluated in patients with hyperthyroid Graves' disease whose thyroid volumes have been accurately estimated with a high resolution ultrasound scanner. One year after 131I treatment, 23.1% (3 out of 13 patients) remained hyperthyroid, 69.2% (9 out of 13) became euthyroid, and 7.7% (1 out of 13) were in a hypothyroid state. Since three patients in a hyperthyroid state one year after treatment were subsequently treated with either antithyroid drugs or additional 131I treatment, the remaining ten patients (9 euthyroid and 1 hypothyroid patients) have been followed up for three more years. Two patients developed a hypothyroid state three years after treatment and one patient four years after treatment. Overall, 60% (6 out of 10 patients) were in a euthyroid state and 40% (4 out of 10) in a hypothyroid state, four years after 80 Gy 131I treatment. There was no significant difference between eu- and hypothyroid groups in the sex ratio, age, radiation dose, therapeutic dose, thyroid gland volume, 24-hr 131I uptake, the effective half-life of 131I in the thyroid or the duration of hyperthyroidism. In our preliminary studies, the incidence of late hypothyroidism in our 131I treatment is similar to those previously reported. These suggest that uncertain factor(s), such as inhomogeneity of iodine distribution in the thyroid, unequal sensitivity of the thyroid cells to the radiation, and/or persistent destructive effects of the autoimmune process may influence the long-term effect of 131I treatment of Graves' disease.

Operative ultrasonography during hepatobiliary and pancreatic surgery.

On the basis of our experience with operative ultrasonography during hepatobiliary and pancreatic surgery, its indications, benefits, and disadvantages are summarized. High-resolution operative ultrasound scanning of the liver, biliary tract, and pancreas was performed during 357, 735, and 242 operations, respectively. The benefits of operative ultrasonography were categorized as acquisition of diagnostic information otherwise not available, replacement for or complement to operative radiography, and guidance of surgical procedures. Operative ultrasonography provided beneficial information during 73 of 82 hepatic operations (89.0%), 57 of 69 noncalculous biliary operations (82.6%), and 177 of 242 pancreatic operations (73.1%). Operative ultrasonography was significantly superior (sensitivity 93.3%) to other screening tests for diagnosing liver metastasis from colorectal carcinoma evaluated in 189 patients, and it detected previously unrecognized metastatic tumors in 18 patients (9.5%). For screening common bile duct calculi during 666 operations, operative ultrasonography and operative cholangiography were comparable in all indices of accuracy except for a higher predictability of a positive test of operative ultrasonography (94.8% versus 71.7%). For diagnosing portal vein invasion of pancreatic carcinoma, operative ultrasonography provided better overall accuracy than preoperative studies (89.7% versus 64.1%). On the basis of operative ultrasound findings, previously planned surgical procedures were altered in 32 of 82 hepatic operations (39.0%) and 24 of 145 pancreatic operations for chronic pancreatitis (16.6%). Operative ultrasound guidance of various surgical procedures was performed during 88 hepatic and 84 pancreatic operations, including 40 ultrasound-guided hepatectomies and 42 pancreatotomies. Operative ultrasonography has a number of advantages, such as safety and speed in performance, wide application, high diagnostic accuracy, and ability of guiding procedures. Its disadvantages are the limitation of the fields of view in certain applications, the need for special equipment, and a slow learning curve.

Noninvasive ultrasonic biopsy: evaluation of early arteriosclerotic lesions progression in normal asymptomatic, hyperlipidemic, and diabetic subjects.

Noninvasive ultrasonic biopsy (UB) is a method of detecting early arteriosclerotic changes by high-resolution ultrasound scanning of the carotid and femoral bifurcation. Six UB classes (scoring 0 to 10) have been identified in 2000 asymptomatic subjects and 600 vascular patients followed up for four years. The incidence of silent coronary ischemia (tested by effort test) and the occurrence of symptomatic events in four years are increased in advanced classes and with increasing UB score. The rate of progression (ROP) in four years to the next UB class has been defined in normal subjects (1.4% in class I, 3.1% in II, 10.7% in III, 17.9% in IV, and 79.2% in class V). In a group of 305 asymptomatic hyperlipidemic subjects and in a group of 269 diabetics the ROP (in four years) was significantly higher. Therefore ultrasonic biopsy is useful to identify subjects at risk of coronary ischemia and cardiovascular events and to follow up noninvasively the progression of arteriosclerosis.

Clinical value of ultrasonography in the detection and removal of radiolucent foreign bodies

A series of 39 consecutive patients with a suspected retained foreign body in the hand and in whom standard soft issue radiographs were negative were examined by real-time, high-resolution ultrasound scan. At operation 20 patients had radiolucent foreign bodies (18 wood, 2 thorns) removed. Ultrasound scan correctly localized 19 of the foreign bodies before surgery and failed to detect one. No foreign body was found in 19 patients. Ultrasound scan falsely predicted the presence of a foreign body in two of these cases. High-resolution ultrasound scanning is a sensitive, accurate technique for diagnosing foreign bodies which are otherwise difficult to demonstrate by conventional radiographic techniques, and provides accurate three-dimensional localization of the object which is of value to the surgeon at operation.

Can Ultrasound Reliably Diagnose Ectopic Pregnancy?

A total of 252 women with amenorrhoea and with abdominal pain or vaginal bleeding, or both, had an emergency high-resolution ultrasound sector scan. In 100 women the symptoms were unrelated to any identifiable abnormal ultrasound finding, none of them was pregnant and their symptoms settled spontaneously; 33 other women had follicular or luteal cysts and 30 had pelvic inflammatory disease. Histological examination confirmed an ectopic pregnancy in 60 women (24%); in seven a live fetus was observed outside the uterus allowing a confident diagnosis of ectopic pregnancy; in 27 the thickness of the endometrium was greater than 10 mm (sensitivity 50%, specificity 84%, positive predictive value 28%, negative predictive value 87%); in 15 the uterine area measurement was less than 20 cm2 (sensitivity 72%, specificity 41%, positive predictive value 20%, negative predictive value 79%); and 43 had an adnexal mass volume greater than 10 ml separate from the ovary (sensitivity 85%, specificity 37%, positive predictive value 23%, negative predictive value 90%). Only three had negative ultrasound findings. The negative predictive value of an ultrasound examination could be increased to 96% by using a combination of these ultrasound features. The addition of hCG (greater than 25 i.u./l) improved the specificity to 98% and the negative predictive value to 100%. These criteria may improve the ultrasound diagnosis of ectopic pregnancy.

Can ultrasound reliably diagnose ectopic pregnancy?

A total of 252 women with amenorrhoea and with abdominal pain or vaginal bleeding, or both, had an emergency high-resolution ultrasound sector scan. In 100 women the symptoms were unrelated to any identifiable abnormal ultrasound finding, none of them was pregnant and their symptoms settled spontaneously; 33 other women had follicular or luteal cysts and 30 had pelvic inflammatory disease. Histological examination confirmed an ectopic pregnancy in 60 women (24%); in seven a live fetus was observed outside the uterus allowing a confident diagnosis of ectopic pregnancy; in 27 the thickness of the endometrium was greater than 10 mm (sensitivity 50%, specificity 84%, positive predictive value 28%, negative predictive value 87%); in 15 the uterine area measurement was less than 20 cm2 (sensitivity 72%, specificity 41%, positive predictive value 20%, negative predictive value 79%); and 43 had an adnexal mass volume greater than 10 ml separate from the ovary (sensitivity 85%, specificity 37%, positive predictive value 23%, negative predictive value 90%). Only three had negative ultrasound findings. The negative predictive value of an ultrasound examination could be increased to 96% by using a combination of these ultrasound features. The addition of hCG (greater than 25 i.u./l) improved the specificity to 98% and the negative predictive value to 100%. These criteria may improve the ultrasound diagnosis of ectopic pregnancy.

Correlation of neuropathologic findings, computerized tomographic and high-resolution ultrasound scans of canine avian sarcoma virus-induced brain tumors

The location, size, geometry and neuropathological findings of anaplastic astrocytomas (AA), gliosarcomas and sarcomas induced by the avian sarcoma virus (ASV) in dogs were compared with images generated using computerized tomography (CT) and real time high-resolution ultrasound (HRUS). Seven AA showed a wide range of findings on CT. Pre-contrast CT scans showed that the tumors could be hyper, hypo, or isodense. Three of seven AA had no contrast enhancement; two of these tumors were also isodense which resulted in a false-negative CT exam. Partial enhancement was seen in one tumor. This resulted in a sensitivity of detection of 72%. Real time HRUS was able to define tumor location, size and geometry of the AA missed or incompletely imaged by CT. All tumors were hyperechoic. Inhomogeneity of the echo pattern was due to hemorrhage, cyst formation, and necrosis within the tumors. Such secondary tumor characteristics were more accurately defined by HRUS compared to CT. Vasogenic edema in the brain surrounding tumors was of low density on CT and hypoechoic or indistinguishable from normal brain on US. Similar findings were seen in six gliosarcomas, two of which were not visualized by either pre- or post-contrast enhanced CT scans (sensitivity of 66%). Sarcomas differed in that they were either hyper or isodense; none were hypodense. The area of increased density matched the tumor geometry and correlated with dense cellularity and reticulin deposition. All 13 sarcomas showed contrast enhancement (100% sensitivity), but in two tumors, contrast enhanced CT underestimated the size of the tumor. Because of the large size and multiplicity of the sarcomas, HRUS imaging was not able to resolve the entire tumor volume because of limited imaging access. Intravenously injected horseradish peroxidase (HRP) crossed the tumor blood-brain barrier (BBB) only in those tumors in which contrast enhancement was seen. These studies suggest that intraoperative HRUS imaging may be useful in detecting and delineating human AA incompletely visualized by CT.

Single fetal death in twin gestation.

S INGLE FETAL DEATH is an unusual complication of a twin pregnancy. Occasionally, death may be attributed to placental insufficiency associated with maternal disease. However, the cause of death is usually unclear. Theoretical explanations include cord accidents, twin-to-twin transfusion syndrome, and placental abruption. It appears that the surviving twin is at risk for perinatal morbidity and mortality. The incidence of neurologic sequelae was reported to be 20%) l and a recent review of 14 published reports indicated that 46.2 % of the liveborn twins suffered major morbidity or death. 2 The prenatal death of one twin could result in the transfer of tbromboplastin to the live fetus. Thromboembolism might then produce multiple organ injury from intravascular coagulation within the shared fetal circulation, in the absence of maternal coagulopathy. It is also feasible that in cord accidents, damage to the survivor occurs at the time of the insult, which results in the demise of the co-twin. Whether neurologic injury to the survivor could precede death of the co-twin is an intriguing question. The answer becomes crucial in the discussion of whether early delivery might be of benefit to the remaining twin. Perinatal neuropathology cannot establish the nature and timing of the insult, as there is no single pathologic change in the neonatal brain that is specific for a particular etiologic factor. Preterm delivery and intrapartum complications resulting in neonatal morbidity make it difficult to assess whether a given outcome was related to an antepartum event. Currently used methods of fetal assessment, such as the non-stress-test (NST), contraction-stress test (CST), and biophysical profile score (BPS), will give no indication of brain damage unless there is brainstem involvement. The antenatal diagnosis of intraventricular hemorrhage (IVH) can be made by high-resolution ultrasound scans of the fetal head. IVH is the most common neurologic lesion resulting from perinatal asphyxia or trauma and preterm delivery. However, IVH does not seem to be a prominent pathologic feature in this clinical situation. This may reflect failure of diagnosis, as neonatal head scans of high-risk neonates are not performed routinely in many centers. The literature suggests that neurologic injury after single fetal death in twin gestation occurs largely to the cortical white matter from thromboembolism and/or ischemia. Hence, it is unlikely that ultrasound or computerized tomography (CT) scans will be useful for antenatal diagnosis of neurologic damage in the survivor. The newer technique of magnetic resonance imaging (MRI) could potentially detect this kind of neurologic lesion in the early stages and is an area for future investigation. The risk of maternal complications such as preeclampsia and disseminated intravascular coagulation (DIC) must be considered in any approach to management. Additional factors, including the psychologic impact on the mother, a theoretical risk of delayed sepsis, and the possibility of intrapartum problems (obstructed labor or fetal distress), create a complex and perplexing problem for the clinician. Maternal transfer to a tertiary care perinatal center is recommended to provide the intensive fetal surveillance, neonatal care, and pediatric follow-up which becomes necessary. Finally, in the area of prevention, new techniques to measure fetal and uterine blood flow using pulsed Doppler ultrasound may allow earlier detection of twin to twin transfusion syndrome than standard biometric evaluation.

Should women at high risk of neural tube defect have an amniocentesis?

As part of an investigation into the practical problems of a maternal serum alphafetoprotein (AFP) neural tube defect (NTD) screening programme carried out in Mid Glamorgan, South Wales, between 1977...

Sonography of infantile polycystic kidney disease.

Seven children aged 1 day to 12 years with infantile polycystic kidney disease (IPCD) were evaluated by a new high-resolution real-time ultrasound scanner. Instead of the monotonous increased echogenicity of renal parenchyma seen with earlier ultrasound equipment, the echo texture of IPCD became more differentiated, showing disseminated tiny cysts associated with high-amplitude echoes. Even in the newborn, cysts as small as 2 mm in diameter could be detected. Analysis of the new sonographic features of IPCD reveals specific "pepper and salt" and "striped" patterns. In association with such well-known sonographic findings as bilateral enlarged kidneys and poor definition of renal sinus, medulla, and cortex, this pattern allows one to make the final diagnosis of IPCD.

Duplex scanning of the thyroid

High resolution ultrasound scanners are used to image nodular thyroid glands and in the study of thyroid malignancy. There are no specific ultrasonic characteristics of malignant lesions to distinguish them from benign conditions. Preliminary results using a Duplex ultrasound scanner shows that the detection of a high frequency Doppler-shift signal from the superior thyroid artery is indicative of an overactive thyroid. In a study of 23 consecutive patients who were being investigated for possible hyperthyroidism, 15 were found to have normal thyroid function and 8 to be overactive. The normals had a mean systolic peak frequency of 1.77 ± 1.75 kHz, and the hyperthyroid group 4.08 ± 1.5 kHz. This result is highly significant, having a p value < 0.0002 (Mann-Whitney U Test). In another 10 patients with solid lesions, one was diagnosed as follicular carcinoma. High frequency Doppler shift signals, similar to those found in carcinoma of the breast, were detected in the periphery of the lesion but were not found in nine cases of adenoma. Duplex scanning may assist in the investigation of hyperthyroidism and in the differential diagnosis of benign and malignant lesions.

Neonatal echoencephalography

The recent development of high-resolution real-time ultrasound scanners has coincided with the awareness of the high incidence of intracranial haemorrage in low birthweight babies, resulting in a considerable expansion in the use of echoencephalography in newborns in recent years. The uses are now further expanded and an overview of the subject is presented.