MHz Linear Scanner Research Articles

Abstract TP168: Angiography-Like Grading of Carotid Artery Stenosis with B-Flow Ultrasound: 3D-Ultrasound Supported Comparison with Computer Tomography Angiography Results in a High Accuracy

Background: Evaluation of various imaging modalities for grading internal carotid artery (ICA) stenosis can be performed by comparison of minimal lumen diameters (MLD) as well as percent ICA-stenosis calculated with a healthy distal reference segment (NASCET method). The two dimensional B-Flow (BF) ultrasound (US) imaging method displays stenoses in a similar fashion as reference methods like multi-slice CT-angiography (MS CTA) and in part like catheter angiography. Aim: to evaluate the accuracy of BF-US carotid stenosis grading at NASCET locations adjusted with 3D-color-Doppler ultrasound by comparison with MSCTA. Methods: Patients were screened by doppler US velocity criteria after informed consent. 3D-US was made for distance taking and search for anatomical markers. CTA were compared with BF-US in 91 ICA stenoses of 69 patients at identical projections of longitudinal sections. 58 low to high grade ICA stenoses were imaged by selective angiography and compared with CTA. Diameters of stenosed ICA were rendered coaxial on CTA. Angiography was made with AXIOM (Siemens, Germany), MSCTA with SOMATOM (Siemens, Germany); Ultrasound Logic 9 with 8 Mhz linear scanner for BF-US and a 10 Mhz 3D-US probe, GE, USA. All readings were by two independent observers for each technique. Quantitative angiography was done with MEDIS software (Netherlands), Bland-Altman analysis and statistics with SPSS (USA). Identical planes were finally confirmed by overlay technique of BF with 3D-US and CTA in addtition to the use of anatomical markers. Results: Degree of stenosis was slightly understimated by CTA compared with angiography with mean differences (±SD) of -0.4% (±6.1%) for longitudinal sections. In this cohort, discrimination of binary 50% NASCET stenosis with BF-US had a 90% sensitivity, 94% specifity and an accuracy of 91%; discrimination of binary 70% NASCET stenosis with BF-US had a sensitivity of 88%, specifity of 93% and an accuracy of 92%. Conclusion: diagnostic performance of CTA proved to be excellent compared with angiography and 3D-US adjusted BF-US measurements were highly accurate, when using corresponding projections. BF-US may be a valuable additional tool for screening and confirmation of CAS for therapeutic stratification.

Ultrasonographic assessment of the spleen in 60 healthy sheep

AIM: To evaluate the sonographic appearance, size, location and shape of the spleen in 60 healthy sheep. METHODS: A 7.5 MHz linear scanner was used to examine the location, extent and appearance of the spleen from the left side of the sheep, in intercostal spaces (ICS) 8–12 and caudal of the last rib. RESULTS: The ultrasonographic appearance of the splenic parenchyma was homogeneous with a thin, smooth echogenic capsule. The spleen could be visualized in intercostal spaces 9–12 in all sheep, in intercostal space 8 in 25/60 sheep (42%) and caudal of the last rib in 24/60 sheep (40%). In intercostal spaces 8–12 and caudal of the last rib the spleen was visible in 16/60 sheep (27 %). The distance from the dorsal margin of the spleen to the spinous processes of the thoracic vertebrae was greatest in the 8th intercostal space: mean 19.32 (SD 2.76) cm and smallest in the 12th intercostal space: mean 6.61 (SD 1.94) cm. The dorsoventral splenic extent was greatest in the 11th intercostal space: mean 13.69 (SD 2.2) cm and smallest in the 8th intercostal space: mean 7.13 (SD 2.5) cm. The thickness of the spleen ranged from 21 (SD 9.0) mm in the 8th intercostal space to 49 (SD 7.0) mm in the 11th intercostal space. The mean vessel diameter was 1.9 (SD 0.7) mm. Spleen size did not correlate with age, body weight, or thoracic and abdominal circumference. CONCLUSIONS: Ultrasonography is a useful, straightforward and non-invasive method for evaluation of the spleen in sheep. CLINICAL RELEVANCE: These findings provide information which can be used as a reference for sonographic spleen examination and diagnosis of splenic lesions in sheep.

Ram breeding soundness - some common scrotal and testicular abnormalities

Epididymitis caused by Actinobacillus seminis/Histophilus ovis (gram-negative pleomorphic organisms) is a major cause of ram infertility in the UK. Diagnosis is confirmed by sequential ultrasonographic examination of the pampiniform plexus, testicle and tail of the epididymis undertaken as the 5 MHz linear scanner head is moved distally. In cases of unilateral epididymitis, hemicastration is generally ill-advised because of the extensive adhesions between the inflamed (and abscessed) epididymis and the vaginal tunics. Sperm granulomas may develop over several years after vasectomy but do not affect the sexual behaviour of the vasectomised ram; ultrasonographically there is testicular atrophy and marked enlargement of the tail of the epididymis such that the scrotal contents have a bi-lobed appearance.

Abstract 3772: High Precision and Accuracy of B-flow Ultrasound Morphometry of Internal Carotid Artery Stenosis: Improved Non-invasive Stenosis Grading

Background: Evaluation of various imaging modalities for grading internal carotid artery (ICA) stenosis can be performed by comparison of minimal lumen diameters (MLD) as well as percent ICA-stenosis calculated with a healthy distal reference segment (NASCET method). The new B-Flow (BF) ultrasound (US) imaging method displays stenosis in a similar fashion as reference methods like catheter angiography (A) and multi-slice CT-angiography (MS CTA). Aim: to evaluate the accuracy of MSCTA by using multiplanar reformation (MPR) for measuring ICA stenosis compared with of A as well as accuracy and precision of BF-US compared with MSCTA at corresponding projections and locations. Methods and patients: CTA of ICA were compared with A in 37 low to high grade ICA stenoses of patients screened by doppler US velocity criteria. CTA were compared with US in 80 ICA stenoses of 63 patients in a similar fashion at identical projections. Diameters of stenosed ICA were rendered coaxial on CTA. A was made with AXIOM (Siemens, Germany), MSCTA with SOMATOM (Siemens, Germany); Ultrasound Logic 9 with 6-8 Mhz linear scanner, GE, USA. All readings were by two independent observers for each technique. Quantitative A was done with MEDIS software (Netherlands), Bland-Altman analysis and statistics with SPSS (Germany). Identical planes were confirmed by overlay technique. Results: MLD was slightly overestimated by CTA compared with angiography with mean differences (±SD) of 0.093 ± 0.25 mm for longitudinal sections. Pearson correlation coefficient (PCC) was 0.95. NASCET stenosis grade showed no bias between CTA and A (-0,5%±6.23% SD) and resulted in a PCC 0.93 for MPR's compared with A. MLD was slightly underestimated by parasaggital section (PSS) BF-US (0.031mm ± 0.23mm SD) compared with CTA, PCC = 0.96. NASCET ICA-stenoses were slightly underestimated by CTA, with mean differences of 1,16% ± 6,04% (SD), PCC was 0.92. In this cohort, discrimination of binary 50% NASCET stenosis with PSS BF-US had a 87%sensitivity, 86% specifity and an accuracy of 86%; discrimination of binary 70% NASCET stenosis with PSS BF-US had a sensitivity of 92%, specifity of 90% and an accuracy of 90%. Conclusion: diagnostic performance of CTA proved to be excellent compared with angiography and PSS 2D BF-US was highly accurate, when using corresponding projections. 2D BF-US may be a valuable additional tool for screening and confirmation of CAS for therapeutic stratification.

Very high prevalence of thyroid nodules detected by high frequency (13 MHz) ultrasound examination

The prevalence of thyroid nodules in a healthy population is high: in the German Papillon study, nationwide ultrasound screening of more than 90 000 people using 7.5 MHz scanners revealed the presence of thyroid nodules in 33% of the normal population. A study employing more sensitive 13 MHz scanners has not been conducted so far. Six hundred and thirty-five consecutive patients (33% female, 67% male, mean 56.7 years) presenting for a preventive health check up underwent ultrasound screening of the thyroid gland (Siemens Acuson Antares, 13 MHz-linear scanner, B-mode and Power mode) and measurement of the basal TSH (thyroid stimulating hormone) value. Size and degree of vascularization of the thyroid gland and of nodules were determined and analysed retrospectively. In 432 of 635 patients, thyroid nodules could be detected with an increasing incidence with age, in 338 without goiter. Mean thyroid size was 12.3 mL for women and 20.5 mL for men correlating strongly with body weight. Fifty-three percentage of the nodules were smaller than 5 mm. Incidence of thyroid dysfunction was only 4%. No cancerous lesions could be found. Using the 13 MHz technology, we found a substantially higher prevalence of thyroid nodules (68%) than the Papillon study (33%). Even if our population is older than in Papillon, the difference remains in comparable age groups. This is due to the higher sensitivity of 13 MHz scanning. Our study underlines the clinical significance of iodine deficiency and should renew the discussion on routine iodine supplementation.

Sonographische Befunde der Patellasehne und ihrer Insertionsstellen

To examine the use of ultrasonography in the diagnosis of soft tissue lesions in and around the patellar tendon. We analysed the sonograms of 87 patients with knee pain and patellar tendon lesions after clinical observation. We used a 7.5 MHz linear scanner. In cases of bone lesions, a roentgenologic examination was performed. The visualisation of pathologic findings of the patellar tendon such as focal or generalised thickenings, calcifications as well as partial or total ruptures is possible with ultrasound. We could classify six different sonopathologic stages of the jumper's knee syndrome. In addition patellar bursitis and aseptic necrosis of the patella and tibial tuberosity can be identified. Ultrasound examination is a noninvasive, time sparing and economical diagnostic tool to evaluate chronic patellar tendinitis, to plan therapy and to objectively assess the results of treatment.

Thrombosen von Vena subclavia und Vena jugularis sowie Vena cava superior: Sonographische Diagnostik und Therapiekontrolle bei TPA-Lysetherapie

In the suspected diagnosis "superior influx congestion" sonography performed with the 5 MHz linear scanner is suitable as a non-invasive method for the primary diagnosis of thrombotic occlusions of the vena subclavia and vena jugularis interna, and for follow-up monitoring under thrombolytic therapy. In successful lysis it is possible to verify a sonomorphological and Doppler sonographic sequence of stages from the freshly formed, stratified stage via the high-echo to the low-echo thrombus with formation of lacunae, as well as the recanalisation that is seen at first only at the margins and eventually becomes complete with a flow that varies with the respiration.

Image quality of various venous catheters in ultrasound under standardized conditions

Seven different types of venous catheters were visualised under standardised conditions with a 5 mHz linear scanner for comparison of their respective imaging qualities. Under these conditions, all catheters were readily identifiable regardless of fabric and width. Any formation of loops or knots could also be visualised.

Ultrasound in the Diagnosis of Craniosynostosis

Diagnosis of craniosynostosis is based on clinical aspects but may be difficult in some cases where characteristic features are missing and radiographic imaging is necessary. In this context near-field high-frequency ultrasound has been used to evaluate the sonographic characteristics of synostotic sutures and its potential confirming the correct diagnosis. Sutures of 26 infants, aged 2-7 months, were investigated by ultrasound (Siemens Elegra, 7.5 MHz linear scanner). Sonographic features of synostotic sutures were correlated to CT imaging and compared to the sonographic and histopathological findings of normal cranial sutures. Hyperechogenic bridging of sutures with or without ridging were the characteristic aspects of synostotic sutures. All 26 patients could be reliable diagnosed showing partial (n = 21) or total fusion (n = 5) of one or more sutures consisting with craniosynostosis. Length of synostosis was identified exactly by sonography and imaging found to enable a classification of ultrastructural details of bony and soft tissue next to the synostotic suture. Ultrasound is a less expensive, nonradiating and easy-to-handle tool ensuring the diagnosis of craniosynostosis. Sonography offers the potential to be a standard investigation for infants with head deformities suspecting a suture pathology and has been therefore integrated in our craniofacial outpatient clinic as a daily routine method.

Populationsbasierte Studie zu Prädispositionsfaktoren und Häufigkeit der Hüftgelenksdysplasie

To correlate findings of hip ultrasound on day 4-10 of life with sex, intrauterine position and a positive family history for congenital hip anomalies. The SNiP-study ( Survey of Neonates In Pommerania) registered 2256 neonates (2030 term, 226 preterm) between May 2002 and March 2004. Hip ultrasound results of 1043 term and since October 2003 33 preterm neonates were analysed. Time of ultrasound was day 4-10 after birth. Preterm neonates were examined when reaching their corrected term gestational age. Ultrasound was applied with a 7.5 MHz linear scanner and results were classified according to Graf. Chi-square and Fishers exact test were used for statistical analysis. 4.9 % of the screened hips were classified as IIc or higher, 3.1 % were unilateral and 1.7 % bilateral. Incidence was significantly higher (p < 0.023) in females (6.6 %) than in males (3.2 %). There was no significant difference in intrauterine position or positive family history for hip anomalies with 3.7 % for mothers, 1.2 % of fathers and 2.4 % of siblings positive. There was a higher incidence for congenital hip dysplasia in preterms with 6.1 %, which is not significant due to the limited number. Current screening methods miss up to 18 % of newborns with severe hip dysplasia. We were able to demonstrate that screening for congenital hip dysplasia with ultrasound is a diagnostic tool even during the first days of life. There is a significantly higher incidence of congenital hip dysplasia in females, but in contrast to other studies we found no significant difference in intrauterine position or familial history. Earlier diagnosis and therapy on the base of relevant risk factors might correspond with an improved prognosis and outcome. Further studies are warranted to evaluate the significance in preterm neonates.

Transthoracic Ultrasound of Lung and Pleura in the Diagnosis of Pulmonary Embolism: A Novel Non-Invasive Bedside Approach

The diagnosis of pulmonary embolism (PE) presents a considerable challenge and requires a high index of clinical suspicion from the attending physician. In addition, diagnosing PE may require the use of one or more direct and indirect diagnostic methods. Here, transthoracic sonography (TS) provides an alternative and attractive bedside approach which is based on (1) detecting alterations in the lung parenchyma, (2) involvement of the pleura and (3) peripheral perfusion characteristics associated with thromboembolism. Using a 5 MHz or 3.5 MHz convex scanner, occasionally supplemented by a 7.5 MHz linear scanner or colour-flow Doppler mode, the intercostal areas are systematically examined by TS. Most of the PE-related lesions are localised in the lower lobes of the lung and are often associated with an area of pleuritic chest pain. The characteristic sonographic findings of TS in PE are multiple, hypoechoic, pleural-based parenchymal lesions which adopt a wedge-shape. In addition, a central echo may occasionally be detectable within the lesion. Another regular sonographic feature is the involvement of the pleura manifesting as either localised effusion, basal effusion or both. However, several differential diagnoses such as pneumonia, bronchogenic carcinoma, metastases of extra-pulmonary malignancies, and simple pleurisy need to be excluded. Since localisation of PE-associated lesions may occasionally escape sonographic detection, an inconspicuous sonographic result does not fully exclude PE. As detection of PE-associated lesions using chest ultrasonography has a high specificity and sensitivity, can be rapidly performed, is widely available, non-invasive, cost-effective, and avoids transport of critically ill patients to the investigation site, the technique may prove a valuable tool in the diagnosis of PE at bedside facilitating immediate treatment decision. Further, because the method focuses on detection of peripheral lesions it complements other diagnostic techniques employed when PE is suspected.

Ultrasound diagnosis of sternum fractures

With the present study we wanted to examine the value of ultrasonography in the diagnosis of fractures of the sternum. Included in this study were 11 patients with pain in the sternal region and suspected fracture of this area according to case history and clinical examination. We exclusively used a 7.5 MHZ linear scanner. In all 11 cases the fracture was free of doubts diagnosed using ultrasound. A fragment dislocation could be visualized in 10 cases and 1 case showed a fissure of the sternum. The standard lateral X-ray as our reference method confirmed the sonographical diagnosis in all cases. The diagnostical value of ultrasonography of the sternum is at least as high as that of standard lateral X-ray. When a hypoechoic area over the sternum together with a hematoma, a disruption of the cortical bone or a step in the bony outline as a sign for fragment dislocation are found, sternal fracture is the definite diagnosis. Ultrasonography is quickly feasible, non-invasive and gives sufficient information in these cases without side effects.

Sonography of the canine stifle.

When diagnosing disease of the stifle in dogs ultrasonography is a good addition to clinical and radiological examination. Radiology can evaluate the bony aspects of the joint and their relationship to each other. In contrast, sonography allows visualization of the soft tissue. For most evaluations the 7.5 MHz linear scanner is suited best. Normal stifles of 58 dogs of different breeds were evaluated using a standardized examination procedure. This procedure had been derived from that used in humans. The stifle is divided into several regions which are examined and evaluated. These are the suprapatellar, infrapatellar, lateral, caudal and medial region. One hundred twenty seven patients which had problems associated with the stifle joint were examined sonographically after a clinical and radiographic exam. Osteochondrosis dissecans, ruptured cranial cruciate ligament, meniscal damage, arthritis, tumor, post surgical conditions, injuries of the patella, patellar ligament or tibial tuberosity and luxating patella were examined sonographically and the findings recorded.

Prevalence of popliteal cysts in children. A sonographic study and review of the literature.

Popliteal cysts in children differ from those in adults. They are considered to be less frequent and usually appear in the absence of intra-articular lesions. However, their prevalence in asymptomatic children is unknown. We present a prospective epidemiological study of 168 asymptomatic children under 15 years of age hospitalised for various pathologies. Children with knee problems and rheumatic diseases were excluded from the study. The children were examined ultrasonographically with a 7.5 MHz linear scanner. A popliteal cyst could be identified in 4 patients. The prevalence of asymptomatic popliteal cysts was thus 2.4%. For 2 of these patients, we obtained magnetic resonance image of the knee which showed no concommitant intra-articular pathology.

Differentialdiagnostische Treffsicherheit der Mammasonographie im Vergleich zum histologischen Befund und der Mammographie

Aim of our investigations was to present breast-ultrasound as a capable technique in detecting early breast cancer as well as a very efficient method. Patients and Methods: 300 patients with suspicious masses detected either by ultrasound, by mammography or by palpation underwent lumpectomy. Preoperatively, all patients were examined by ultrasound (Acuson 128p, 7MHz linear scanner) by the same examiner independent of any previous results. The masses were divided into different histologies: breast cancer, non-invasive cancer, local recurrence of tumour, fibroadenoma, mastopathy, indifferent masses or others. The corresponding results of mammography were performed by 12 different radiological institutes or departments. The mean age of the patients was 51 years, 46% of the women undergoing operation were younger than 50 years. In 142 cases (47.4%) carcinoma of the breast were found, in 158 cases (52.6%) benign histological changes. TNM-classification of the invasive carcinoma: T1 53.5%, T2 40.5%, T3 6%. Results: Breast-Ultrasound: In 262 cases (87.4%) the ultrasound could predict the histological diagnosis. In 19 cases (6.3%) false positive diagnosis was made, in 3 cases (1%) false negative (the maximal tumour growth being 0.5,1.0 and 1.5 cm in diameter). From 116 invasive breast cancers 113 could be diagnosed clearly by ultrasound. Sensitivity 97.4%, specificity 86.7%, positive predictive value 85.6%, negative predictive value 97.6%. From 16 (5.3%) ultrasonographically histologically indifferent masses no invasive carcinoma was found. Mammography: 276 mammographic results were presented in the study. In 185 cases (67%) the histological findings corresponded to the mammographic diagnosis. False positive results were seen in 22 cases (8%), in 32 cases (12%) a false negative diagnosis was made (comprising 28 invasive breast cancers, 3 carcinoma in situ, 1 local reappearance of cancer). From the 28 carcinoma which were mammographically not recognised, ultrasound could judge 27 clearly as carcinoma, 10 invasive carcinomas and 5 carcinomas in situ were seen in the group of 36 mammographically indifferent findings. Of these 10 cases ultrasound could detect 9 as clearly malignant. Conclusion: Independent of the age of our patients and the density of their breast tissue we were successful in predicting the histological diagnosis of breast tumours in approximately 90% of the cases. We think that recognising over 97% of invasive breast cancer by ultrasound independent of other previous examinations should elevate ultrasound of the breast to the rank of an important gold standard in the screening programme, compared with mammography.

Intraoperative evaluation of coronary anatomy.

Intraoperative evaluation of coronary anatomy without arteriotomy is possible with the aid of high-frequency echocardiography (HFE). The 12 MHz linear scanner can image the coronary arteries with good resolution in the transverse section and the longitudinal course. Indications are the visualization of coronary vessels, localization of stenoses and occlusions, the measurement of vessels and stenoses and the evaluation of anastomoses.

Measuring leg length and leg length difference with the method of real time sonography

A brief presentation of the clinical and radiological methods to measure the leg length and the leg length difference is followed by an outline of the new diagnostic method for measuring the leg length and the leg length difference by means of real-time sonography. Tests conducted on corpses, as well as clinical examples, show that sonography is an ideal method for determining the exact lengths of the femur and tibia. The joint gaps on the hip joint, knee joint and upper ankle joint can be visualised by means of a 5 MHz linear scanner. A 1 mm strong metal bar on the skin and under the scanner are positioned at a right angle to the longitudinal axis of the body so that the bar can be seen in the centre of each joint gap by means of real-time sonography. A measuring device gives the distances of the joint gaps in cm so that the differences correspond to the real length of femur and tibia. This standardised measuring procedure is done by a specially developed bearing and measuring device. The results of the sonographical measurings on 20 corpses and checking after consecutive dissections showed in 75% of the cases a 100% sonographic measuring accuracy of the total leg length. The separately considered results for femur (85%) and tibia (90%) were even better. The maximum sonographic measuring fault was 1.0 cm for the femur (in one case) and 0.5 cm for the tibia, respectively. Thus, sonographic measuring of the leg length offers a reliable, non-invasive and easily performed new method that can be repeated any number of times. It is ideal for the development control of therapeutically influenced as well as spontaneous transformations of leg length differences.

Intraoperative Use of High-frequency Echocardiography for Imaging the Coronary Arteries

Until today, a routinely applicable method is not available for intraoperative imaging of the coronary vessels. Our experience with the first 23 patients is discussed to show whether high-frequency echocardiography (HFE) is able to close this gap and to image the coronary arteries intraoperatively in a manner which can be evaluated. After thoracotomy and connecting the heart-lung machine as well as insertion of a transatrial left ventricular vent, ultrasonography was carried out with a 12 MHz linear scanner with a water prerun in the LAD in all cases, and also in the RCA and circumflex branch in 12 cases using sterile ultrasound gel on the fibrillating heart. The results proved that the method is able to image the coronary arteries with good resolution in the transverse section and in the longitudinal course. HFE can be used in particular to locate the intramyocardial course of coronary vessels and in reoperations, for localization of stenoses and occlusions, for determination of optimal sites for anastomoses, for measuring of vessel diameter and degree of stenosis, and for imaging of anastomoses. It will be possible in the future to image and to check intraoperative dilatation and laser angioplasty with HFE.