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Blood volume flow estimation remains an important task for the functional evaluation of internal organs. In vivo and in vivo flow estimation has been carried out using Flash Echo Imaging in harmonic mode after the administration of microbubble-based ultrasound contrast agents. The in vitro flow volume rate correlated with the constant replenishment level but less so with the video intensity decay rate. The in vivo volume flow rates obtained in four dogs agreed well with CVI-Q (time domain correlation) based flow measurement. Our experimental results indicate that the volume flow rate can be accurately estimated in vitro and in vivo using harmonic Flash Echo imaging.

Objective. To assess the feasibility and usefulness of contrast-enhanced sonography for tumor detection and guidance of liver VX2 tumor ablation and to evaluate post radiofrequency ablation effectiveness. Methods. VX2 tumors were implanted into the livers of 6 rabbits Both conventional and harmonic gray scale and power Doppler imaging were performed with a commercially available scanner to evaluate the liver tumors before and after intravenous injection of a sonographic contrast agent before and after radiofrequency ablation. Contrast-enhanced imaging was used to detect the tumors before ablation, to guide needle insertion, and to measure the ablation sites after radiofrequency ablation. Pathologic examination was performed for comparison Results. Three tumors were seen without contrast enhancement, whereas 10 tumors (

This study evaluates a new reticuloendothelium specific sonographic contrast agent NC100100 (Sonazoid) for detection of liver VX-2 tumors in rabbits. Gray scale imaging of five groups of three rabbits, with hepatic VX-2 tumors implanted 7, 10, 12, 14, and 18 days previously, was performed prior to injection of Sonazoid (dosages, 0.01-0.5 ml/kg). Sonazoid produces induced acoustic emission after uptake in the liver. Therefore, harmonic gray scale images were obtained immediately after injection as well as delayed (by up to 2(1/2) h). Five rabbits (one from each group) also had angiography performed, while all animals were evaluated by pathologic examination. Non-contrast enhanced sonography detected 17 of 61 tumors (29%), as well as three false-positives, while the addition of Sonazoid detected 57 tumors (93%) and one false-positive (P

Two surfactant-based contrast agents, ST44 and ST68, were produced according to US Patent # 5,352,436 and filled with either air, C4F10 (perfluorobutane) or SF6 (sulfur hexaflouride). Ten rabbits received IV injections of each agent/gas combination with 5 repetitions of each dose (range: 0.005–0.13 mL/kg). A custom-made 10-MHz cuff transducer was placed around the surgically exposed distal aorta and audio Doppler signals were acquired in vivo. Quantitative in vivo dose responses were calculated off-line using spectral power analysis and compared to a theoretical model of microbubble dissolution and enhancement. For qualitative comparisons, 10 rabbits were imaged pre- and postcontrast administration (dose: 0.1 mL/kg) in gray-scale and colour. All agent/gas combinations produced marked Doppler enhancement with air bubbles enhancing least of all (p < 0.0001) and ST68-SF6 best of all (maximum: 27.6 ± 2.04 dB; p < 0.012). There were no significant differences between other agent/gas combinations (0.30 < p < 0.70). Theoretical enhancement was within 1 order of magnitude of the experimental observations (i.e., deviations of up to 10 dB). The duration of contrast enhancement was 1–2 min for air-filled bubbles, 3–5 min for SF6-filled bubbles and more than 7 min for C4F10-filled bubbles. In conclusion, ST68-SF6 microbubbles produced most in vivo enhancement of the agent/gas combinations studied. Theory matched the measurements within an order of magnitude.

To evaluate the recently developed ultrasonographic (US) contrast agent SHU 563A, which is specifically taken up by the reticuloendothelial system (RES).Color Doppler imaging (CDI) was performed in a gel phantom, with SHU 563A microbubbles in stationary suspension. CDI was performed in vivo in five woodchucks with natural hepatomas and in 12 rabbits before and after intravenous bolus injections of SHU 563A (0.16-0.48 mL/kg). After a 15-135-minute delay, the liver and spleen were scanned again, and the image findings were compared with pathologic analysis results.Phantom CDI demonstrated a random mosaic color pattern in spite of the lack of flow. This phenomenon, which is associated with bubble rupture, is termed induced acoustic emission. In vivo, delayed imaging demonstrated acoustic emission signals in normal parenchyma, whereas no mosaic color was seen in regions lacking reticuloendothelial cells (e.g., tumors). Four of 12 VX-2 tumors detected with pathologic analysis were detected with US alone; the remaining eight tumors were detected by using US with contrast agent (100%, P = .0078). Nine of 20 hepatomas were detected at baseline US, whereas 17 were detected after administration of SHU 563A (P = .0215). Acoustic emission enabled detection of hepatic tumors as small as 3 mm in diameter.CDI with SHU 563A demonstrates a random mosaic color pattern, even without flow. The characteristic appearance of acoustic emission signals provides a distinctive method of visualizing normal hepatic tissues and substantially improves the detectability of hepatic tumors.

The introduction of safe and efficacious ultrasound contrast agents, which significantly enhance the backscattered signals, has allowed previously inaccessible areas of slow flow to be imaged. However, imaging organ perfusion or small deep-lying vessels remains difficult. The ability of harmonic imaging to resolve these problems has been investigated. Harmonic imaging uses the nonlinear properties of microbubble-based agents by transmitting at the fundamental frequency but receiving at the second harmonic. In vitro measurements revealed a harmonic response 15 dB below the fundamental for a driving frequency of 2.5 MHz at an acoustic pressure of 50 kPa for one particular contrast medium. In vivo, two different gas-filled microbubble agents were administrated to 10 dogs and three rabbits. Three different scanners were used to obtain images of kidneys, liver, heart, and vessels in harmonic and conventional gray-scale, pulsed Doppler, and color Doppler modes. Enhancement lasted significantly longer in harmonic than in conventional modes (94 s; P = 0.00003). Harmonic images were less susceptible to artifacts, such as acoustic shadowing, and a wider range of dosages could therefore be used. A clear increase in the (flow) signal-to-clutter ratio was observed. Harmonic images were, however, very dependent on focal zone settings. These preliminary results demonstrate the potential of contrast-enhanced harmonic imaging, but further studies are required to establish clinical efficacy. © 1997 John Wiley & Sons, Inc. Int J Imaging Syst Technol, 8, 69–81, 1997

Harmonic imaging is a new contrast-specific imaging modality, which utilizes the nonlinear properties of microbubble-based sonographic contrast agents by transmitting at the fundamental frequency but receiving at the second harmonic frequency. The feasibility of improving the detection of slow, small-volume blood flow using real-time harmonic imaging has been investigated in vivo. Proteinaceous microspheres (FS069) were administrated to four dogs, two woodchucks (with multiple hepatomas), and one rabbit. Three different scanners were used to obtain real-time images of kidneys and liver (including vessels) in harmonic and conventional gray scale and color flow modes. The duration of contrast enhancement lasted significantly longer in harmonic than in conventional modes (on average 87 s; P = 0.008). Harmonic images were less susceptible to artifacts, such as acoustic shadowing, and a clear increase in the (flow) signal-to-noise ratio was observed. These preliminary in vivo results demonstrate the feasibility of performing real-time, contrast-enhanced harmonic imaging, but further studies are required to establish clinical efficacy.

To determine the amount and distribution of synovial fluid detectable with ultrasonography (US) of the hindfoot and ankle in asymptomatic volunteers.US was performed with a 7.5- or 10-MHz linear transducer of 60 hindfeet and ankles in 30 volunteers. Presence and amount of fluid were assessed in the ankle joint recesses, adjacent bursae, and tendon sheaths. Symmetry of bilateral fluid was evaluated.Fluid was detected in the anterior recess in 20 ankles (bilaterally in eight volunteers), retrocalcaneal bursa in 30 ankles (bilaterally in 12 volunteers), posterior tibial tendon sheath in 46 ankles (bilaterally in 19 volunteers), and common peroneal tendon sheath in seven ankles (bilaterally in three volunteers). No fluid was seen in the posterior recess. On average, symmetry was present for only the retrocalcaneal bursal and peroneal tendon sheath fluid.US of the hindfoot and ankle commonly depicts articular, bursal, and tendon sheath fluid in asymptomatic volunteers. The presence of fluid in these locations, even when unilateral or asymmetric, does not necessarily imply underlying abnormality.

To evaluate a semiflexible ultrasound (US) transducer inserted through a laparoscopic port to image abdominal structures.Laparoscopic US with a 9.6-mm-diameter, 5.0-7.5-MHz semiflexible transducer with gray-scale, color, and spectral Doppler capabilities was performed in three miniature swine and in 25 patients with a variety of abdominal abnormalities.This miniature US probe was used to locate normal structures such as blood vessels, allowing the surgeon to decide the best approach for dissection. Color and spectral Doppler US proved especially useful in differentiating vascular from nonvascular structures. The presence or absence of stones in the gallbladder and common bile duct was readily determined. It was possible to detect masses and to provide guidance for their aspiration or biopsy within abdominal organs. In 10 cases (40%), laparoscopic US helped the surgeon make the decision for clinical management and altered the surgical procedures.Laparoscopic US was useful in assisting laparoscopic evaluation of abnormalities in the abdomen.

To compare the results of sonographic (US) and magnetic resonance (MR) imaging in detecting pathology of the posterior tibial tendon (PTT) in patients with PTT dysfunction.Twenty-two ankles that were clinically suspected by the orthopedic surgeon to have PTT dysfunction were evaluated with US (10 MHz linear-array transducer) and 1.5 T MR examinations within the same day. The US and MR studies were conducted and interpreted by two sonologists and two musculoskeletal radiologists who were masked to the results of the other study. Four patients had bilateral studies. Classic clinical findings were utilized as a standard reference in staging PTT dysfunction.Eighteen women (mean age 61 years, age range 39-86 years).Based on a commonly accepted staging system for PTT dysfunction, 6 ankles were classified as stage I, 11 ankles as stage II, and 5 ankles as stage III. All stage I ankles were interpreted as having an intact PTT by both MR imaging and US. In the stage II and III tendons, MR imaging demonstrated PTT tears in 12 of 22 examinations, including 11 partial tears and 1 complete tear. US demonstrated PTT tears in 8 of 22 examinations, including 8 partial tears and no complete tears. The findings of US and MR imaging were consistent in 17 of 22 cases (77%). The five inconsistencies were as follows: in 4 cases, US reported tendinosis when MR imaging interpreted partial tears (no change in management); in one case, US diagnosed a partial tear when MR reported a complete tear of the PTT (no change in management because the clinical findings were more consistent with a partial tear).In this study, US and MR imaging of the PTT were concordant in the majority of cases. US was slightly less sensitive than MR imaging for PTT pathology, but these discrepancies did not affect clinical management.

Objective To study the use of power Doppler sonography for assessing changes in vascularity during treatment of fracture sites with low-intensity ultrasound. Methods In 6 dogs (3 pairs), subcutaneous dissection of the midshaft of the ulna allowed symmetrical osteotomies to be made with a reciprocation saw. Three dogs were treated and 3 were used as controls. The fracture site was subjected to 1.5-MHz low-intensity ultrasound (30 mW/cm2) for 20 minutes daily from a therapeutic ultrasonic device. Gray scale sonography was performed to evaluate the fracture site. Power Doppler sonography was used to assess flow patterns at the fracture site and surrounding soft tissue. A sonographic contrast agent was administered intravenously. The dose was 0.2 mL/kg. Results Power Doppler sonography showed an increase in flow around the fracture site in the treated dogs compared with that in control dogs. Color pixel values on day 7 were 3-fold higher in treated legs than control legs and on day 11 were 33% higher in treated legs than control legs. Enhancement after contrast agent administration was consistently higher in treated legs than control legs. Conclusions Power Doppler sonography showed increased vascularity around the fracture sites in treated dogs with and without contrast agent administration.

Wall shear stress is a factor in the development of artherogenesis, but is very difficult to determine with ultrasound. Instead, we estimated shear rates using a clinical ultrasound scanner and compared results from vessels with and without stenoses. Velocity profiles were obtained from color M-mode images on a P700 scanner (Philips Ultrasound, Irvine, CA). Shear rates were calculated off-line as the maximum velocity gradients. In vitro, studies were performed on a flow phantom with a vessel containing a 50% stenosis. Shear rates within the stenosis were significantly higher than those obtained outside the stenosis (p

To evaluate the impact of different gasses on contrast studies a new contrast agent ST68 (US patent 5,352,436) was produced with either air (ST68-Air) or perfluorocarbon (ST68-PFC) filled microbubbles. ST68 was administrated to 11 rabbits. In 4 animals a qualitative comparison of duration and degree of enhancement was performed. ST68-PFC produced greater vascular enhancement than did ST68-PFC, Also, the former achieved gray scale enhancement unlike the latter. Enhancement with ST68-PFC lasted over 8 minutes, while ST68-Air lasted less than 2 minutes. Quantitative dose-responses (averaged over 5 injections) were calculated, via spectral power analysis, using data from 7 rabbits and a 10 MHz cuff-transducer placed around the distal aorta. Maximum enhancement with ST68-Air was 18.3 dB for a 0.13 ml/kg dose, while ST68-PFC produced 26.1 dB of enhancement for a 0.1 ml/kg dose. In conclusion, perfluorocarbon filled microbubbles appear to be superior to air filled ones for use in an ultrasound contrast agent.

This study compared contrast-enhanced ultrasound (US) measures of tumor neovascularity with molecular markers of angiogenesis in a human melanoma xenograft model. A total of 14 mice were implanted with a human melanoma cell line (WM-9) in the thigh. After 2 to 3 weeks, a tumor, approximately 12 mm in diameter, developed. The US contrast agent Optison (Mallinckrodt, St. Louis, MO) was injected in a tail vein (dose: 0.4 to 0.6 mL/kg). Power Doppler and pulse-inversion harmonic imaging (HI) were performed with an Elegra scanner (Siemens Medical Systems, Issaquah, WA) and a 7.5 MHz linear array. Frame-rates of 30 Hz and 0.5 Hz (intermittent imaging) were used for pulse-inversion HI. After surgical removal, specimens were sectioned in the same planes as the US images. Immunohistochemical stains for endothelial cells (CD31), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and cyclooxygenase-2 (COX-2) were performed. Two observers graded the stains (for intensity and percent area), and two other observers graded the US imaging modes (for fractional tumor neovascularity) on the same scale from 0 to 3. Of the 14 mice, 4 failed for technical reasons (i.e., n = 10). Linear regressions indicated statistically significant correlations between percent area stained with COX-2 and power Doppler (r = -0.789; p < 0.01), as well as intermittent pulse-inversion HI (r = -0.795; p < 0.05). There was a trend toward significance between percent area stained with VEGF and intermittent pulse-inversion HI (r = -0.720; 0.05 < p < 0.10). No other comparisons were significant. In conclusion, contrast-enhanced US measures of tumor neovascularity in a human melanoma xenograft model appear to provide a noninvasive marker of angiogenesis corresponding to expression of COX-2. However, the sample size of this study is small and, until further studies have been conducted, these conclusions are preliminary.

Objective To determine whether a contrast agent enhances sonographic detection of bleeding sites in the abdomen and whether contrast-enhanced three-dimensional sonography provides additional information compared with contrast-enhanced two-dimensional sonography. Methods Bleeding sites were created within the livers (n = 3), spleens (n = 5), and kidneys (n = 3) of 3 dogs. A sonographic contrast agent with vascular and parenchymal enhancement capabilities was administered intravenously at a dose of 0.02 mL/kg. Before and after each contrast agent injection, the bleeding sites were imaged with two- and three-dimensional sonography in gray scale harmonic imaging and color flow modes. Sonographic findings were compared with gross pathologic findings. Results Noncontrast-enhanced sonography was not able to show the specific location of the active bleeding in any of the organs evaluated. The contrast agent enhanced the sonographic detection of blood flow in normal vessels and extravasated blood from damaged vessels or organs in all cases. Intrasplenic and intrahepatic hematomas were better identified on delayed imaging sequences because there was marked enhancement of the normal parenchyma, whereas the hematomas remained unenhanced. Reconstructed three-dimensional sonography showed spatial relationships of the bleeding sites and surrounding structures. Gross pathologic findings were consistent with the contrast-enhanced sonographic results. Conclusions Contrast-enhanced sonography improves the detection and evaluation of abdominal bleeding sites. Contrast-enhanced three-dimensional sonography appears to provide additional information when compared with two-dimensional sonography.

Wideband harmonic imaging (with phase inversion for improved tissue suppression) was compared to fundamental imaging in vivo Four woodchucks with naturally occurring liver tumors were injected with Imagent® (Alliance Pharmaceutical Corp., San Diego, CA) Randomized combinations of dose (0.05, 0.2 and 0.4 ml/kg) and acoustic output power (AO; 5, 25 and 63% or MI ≤ 0.9) were imaged in gray scale using a Sonoline Elegra scanner (Siemens Medical Systems, Issaquah, WA). Tumor vascularity, conspicuity and contrast enhancement were rated by three independent observers. Imagent produced marked tumor enhancement and improved depiction of neovascularity at all dosages and AO settings in both modes. Tumor vascularity and enhancement correlated with mode, dose and AO (P

We evaluated the ability of power Doppler sonography to show increased soft-tissue blood flow in patients with reflex sympathetic dystrophy of the lower extremity.Power Doppler sonography was performed in 30 patients with reflex sympathetic dystrophy of the lower extremity and in 26 asymptomatic control subjects. The bilateral power Doppler sonograms that were obtained of the soft tissues of the dorsum of the foot of each subject were grouped in pairs, and three sonologists who were unaware of clinical information independently reviewed the images. Images were evaluated for the amount of power Doppler signal shown on the following scale: 1 = no flow or minimal flow; 2 = mild flow; 3 = moderate flow; and 4 = marked flow.More power Doppler flow was seen in the patients with reflex sympathetic dystrophy than in the control subjects (p.005). In addition, side-to-side asymmetry of flow was seen in patients, but this trend was not statistically significant (p.20). Receiver operating characteristic (ROC) analysis showed that combined flow and asymmetry were more related to reflex sympathetic dystrophy than either parameter alone (area under the ROC curve: for flow, 0.748; for asymmetry, 0.566; for both, 0.799). We found that when the sum of power Doppler flow in both feet was greater than or equal to five, and asymmetry of flow was greater than or equal to one, the sensitivity of power Doppler sonography for reflex sympathetic dystrophy was 73% and the specificity was 92%.Patients with reflex sympathetic dystrophy of the lower extremity have increased power Doppler flow compared with asymptomatic control subjects. Patients may also exhibit more side-to-side asymmetry of flow than control subjects.

Color Doppler sonographic detection of tumor flow within superficial melanoma metastases was investigated to determine if tumor size, vessel size, or vessel number influences signal detection. Color Doppler imaging of 32 pathologically proved melanoma metastases was performed at 6 MHz with color Doppler imaging parameters optimized for each lesion scanned. All lesions were measured in three dimensions and the presence or absence of internal flow was documented. Seven surgically excised metastases underwent immunohistochemical staining for endothelial markers. Internal flow was detected in 21 of 32 masses and was completely absent in 11. In comparison to all masses without flow, the masses with flow had significantly greater anteroposterior dimensions (P < 0.00036) and volumes (P < 0.01). Histologically, mean vessel diameter in masses with flow was significantly greater (P < 0.05) than in those without flow, but mean vessel number was not significantly different. In conclusion, detectability of tumor blood flow in superficial melanoma metastasis may be related more to tumor size and vessel size than vessel number. Failure to detect color signal within a superficial melanoma mass does not indicate a lack of internal vascularity.

The purpose of this study was to describe the sonographic appearances of melanoma metastases of the skin, subcutaneous tissues, and superficial lymph nodes.Gray-scale sonography was performed on 31 superficial melanoma metastases in 18 patients. Discreteness of borders, contours, echogenicity, echotexture, and degree of acoustic through-transmission were evaluated for each lesion. Color Doppler sonography was also performed on 25 of the 31 lesions, by which the amount of internal color flow was qualitatively assessed.Twenty-eight (90%) of the 31 metastases had well-defined borders. Contours were smooth in 17 (55%), lobulated in 12 (39%), and spiculated in two (6%). Nineteen metastases (61%) were hypoechoic to muscle, 10 (32%) were isoechoic, and two (6%) were hyperechoic. Echotexture was homogeneous in six lesions (19%), mildly heterogeneous in 13 (42%), moderately heterogeneous in 11 (35%), and markedly heterogeneous in one (3%). Twenty-two lesions (71%) showed enhanced acoustic through-transmission. Of the 25 melanoma metastases for which we performed color Doppler sonography, 18 (72%) had internal arterial color flow and seven (28%) did not. The flow was characterized as mild in 13 (72%) of 18, moderate in four (22%), and marked in one (6%).On sonography, superficial melanoma metastases typically are well-defined hypoechoic lesions with smooth or lobulated contours, mild to moderate heterogeneity, and enhanced acoustic through-transmission. Internal flow revealed by color Doppler sonography is present in many, but not all, superficial melanoma metastases.

The value of sonographic guidance during video-assisted thoracoscopic surgery (VATS) was studied in 13 patients with one or more peripheral pulmonary nodules who later underwent wedge resection.After a review of the chest radiographs and CT scans of each patient, sonographic guidance for VATS was requested by the attending surgeon when the nodule or nodules in question were determined to be too small or too deep in the lung parenchyma from the pleural surface for location by VATS. A multifrequency (5.0-, 6.5-, or 7.5-MHz) sonographic probe was introduced through a thoracoscopic port during VATS. The nodule or nodules in question were located by intraoperative sonography or determined by inspection and confirmed by sonography before wedge resection. The size and location of each lesion and the time needed for sonographic guidance were recorded.Sonography revealed a peripheral pulmonary nodule in 12 of the 13 patients. Of these, it confirmed the suspected location of the pulmonary nodule in six. In the remaining six patients, the surgeon was unable to locate the nodule without the use of sonography. The additional operative time required for sonographic guidance during VATS averaged 7.5 min. However, the time commitment of radiology personnel during surgery varied and was sometimes lengthy (maximum, 150 min).Sonographic guidance during thoracoscopy helped to locate lesions and determine their size and proximity to pleural surfaces. Sonographic guidance can be done safely and can be completed expeditiously. Unlike percutaneous hookwire techniques, sonographic guidance does not require an additional invasive procedure to locate the peripheral pulmonary nodule.

This study evaluated the ability of laparoscopic ultrasonography to detect, localize, and characterize focal liver masses. Laparoscopic ultrasonography and CT portography of the liver were performed in 13 patients with known or suspected malignancy. Laparoscopic ultrasonography directly influenced surgical management in four (31%) cases ; three by detection of small focal masses and one by exclusion of masses suspected on CT portography. Laparoscopic ultrasonography provide guidance for biopsy or added important anatomic information in three cases. Laparoscopic ultrasonography was complementary to CT portography but added no additional information in three cases, and it failed to provide any information in two cases. Laparoscopic ultrasonography was falsely negative in one case. In this preliminary series, laparoscopic ultrasonography assisted surgeons in critical decision-making by either providing important new information, clarifying questionable areas, or complementing CT pornography.

To evaluate the impact of superficial ultrasonography (US) on clinical management of melanoma.Superficial US in areas at high risk for local recurrence or nodal metastases was performed in 33 patients with cutaneous melanoma. Impact categories were assigned to each US study (n = 55): category 3, US added information that altered clinical management; category 2, US added information that did not change management; category 1, no added information and management unchanged; category 0, not helpful or was misleading.Twenty-two US studies (40%) were category 3: detection of nonpalpable metastases altered surgical therapy (n = 2), demonstration of pharmacodynamic response to chemotherapy (n = 5), and determination of benignancy or malignancy (n = 15). Nine (16%) were category 2: identification of nonpalpable metastases did not alter management. Twenty-two (40%) were category 1: supported clinical impression of no metastases (n = 18) or helped confirm cutaneous, subcutaneous, or nodal metastases (n = 4). Two (4%) were category 0: missed proved metastases.Superficial US affected management of melanoma by allowing detection and characterization of masses, guidance of biopsy, and assessment of pharmacodynamic response.

Extensive efforts are currently underway to develop efficacious ultrasound contrast agents. The ideal agent would be (1) nontoxic; (2) injectable intravenously; (3) capable of traversing the pulmonary, cardiac and capillary circulations; and (4) stable for recirculation. It is only within the last decade that pharmaceutical companies and researchers have approached this goal. Contrast agents have the potential to improve the diagnostic capabilities of ultrasound imaging. Enhancement of Doppler signals from small and/or deep lying vessels have been investigated, as well as increases in the difference in echogenicity between normal and adjacent abnormal (e.g. tumor) tissue in organs such as the liver and spleen. Further details on the many different types of contrast agents and their potential clinical applications can be found in several, recent review articles and their associated bibliographies1,2.

The purpose of this study was to assess the ability of a sonographic contrast agent to increase parenchymal echogenicity and improve tumor visibility. The agent is an emulsion that changes at body temperature from nonechogenic submicrometer liquid droplets to echogenic 1 to 5 microns microbubbles, capable of transversing the pulmonary and capillary circulations. Peripheral venous injections (dosages of 0.05 to 0.8 ml/kg) were administered to five woodchucks (three with multiple hepatomas), 12 rabbits (with renal VX-2 tumors), and four dogs. Ultrasonograms were acquired from kidney, liver, tumors (including tumor vessels) and normal vessels. Uptake and washout curves were generated via videodensitometry. Finally, Doppler shifts from a cuff transducer around the celiac trunk were analyzed to provide an in vivo dose-response curve. Vascular enhancement, including hepatoma and VX-2 tumor vessels, was seen for 2 to 3 min. Maximum enhancement was 18.7 dB for a 0.6 ml/kg dose. Enhancement of normal liver and kidney parenchyma was observed in all three species for up to 20 min. Small hepatomas became more echogenic centrally, but larger tumors showed no increase in central echogenicity. In conclusion, improved tumor visibility and parenchymal enhancement was demonstrated in animals.

Ultrasound is useful in evaluating the integrity of silicone gel breast implants. This modality is now being applied intra-operatively to determine the location of free silicone from leaking or ruptured implants, and to provide guidance for the surgeon in its removal or biopsy. Intra-operative ultrasound was performed on 17 implants in 10 patients. In 7 patients additional three-dimensional (3D) ultrasound images were obtained. Of the 17 implants, 8 had free silicone extending beyond the fibrous capsule and 9 were ruptured with silicone contained within the capsule. In the case of extra-capsular rupture, free silicone could easily be localized in the breast and axilla. 3D imaging was helpful in determining the exact size and extent of the free silicone; In two cases scar and muscle infiltration prevented complete removal, but the ultrasound assisted in localizing involved tissue for biopsy. The intra-operative ultrasound confirmed preoperative findings and added little time to the surgical procedure. Intra-operative and 3D ultrasound can provide valuable information during surgical explantation of ruptured implants

An ultrasound contrast agent (EchoGen; Sonus Pharmaceuticals, Bothell, WA) was evaluated in vivo. The agent changes at body temperature from non-echogenic submicron liquid droplets to echogenic gas microbubbles (1-2 mm*) capable of traversing the pulmonary and capillary circulations. IV injections were given to 5 woodchucks, 4 dogs and 12 rabbits (dose: 0.05-0.8 ml/kg). Color Doppler, color amplitude and B-mode images were acquired from kidneys and vessels. A segmental branch of the renal artery was ligated providing a model of ischemia. Increased flow signal intensities were observed for 2-3 minutes. Normal vessels and the area of ischemia were visualized using both color modes. An in vivo dose response curve was calculated. The curve was nonlinear with 18.7 dB maximum enhancement. Parenchymal enhancement was observed, and uptake and washout curves generated. Enhancement lasted 20 minutes. Ischemia was also seen using B-mode. In conclusion, EchoGen produces vascular and parenchymal enhancement. Ischemia was seen with all imaging modes

Background This prospective multi-institutional study was designed to define the accuracy of ultrasonography, when performed in an orthopaedic surgeon's office, for the diagnosis of rotator cuff tears. Methods An anatomic diagnosis and a treatment plan were made on the basis of office-based shoulder ultrasonography, physical examination, and radiographs for ninety-eight patients (ninety-nine shoulders) with a clinical diagnosis of a rotator-cuff-related problem. The results of the ultrasonographic studies were then compared with the results of magnetic resonance imaging and the operative findings. Results Office-based ultrasonography led to the correct diagnosis for thirty-seven (88%) of forty-two shoulders with a full-thickness rotator cuff tear or both full and partial-thickness tears, twenty-six (70%) of thirty-seven shoulders with a partial-thickness rotator cuff tear only, and sixteen (80%) of twenty shoulders with normal tendons. In no case was the surgical approach (open or arthroscopic) that had been planned on the basis of the ultrasonography altered by the operative findings, but the operative finding of a full-thickness tear resulted in an arthroscopic cuff repair in four shoulders. Magnetic resonance imaging led to the correct diagnosis for forty (95%) of forty-two shoulders with a full-thickness rotator cuff tear or both full and partial-thickness rotator cuff tears, twenty-seven (73%) of thirty-seven shoulders with only a partial-thickness tear, and fifteen (75%) of twenty shoulders with normal tendons. There were no significant differences between magnetic resonance imaging and ultrasonography with regard to the correct identification of a full-thickness tear or its size. The sensitivity of ultrasonography for detecting tear size in the anterior-posterior dimension was 86% (95% confidence interval, 71% to 95%), and that of magnetic resonance imaging was 93% (95% confidence interval, 81% to 99%) (p = 0.26). The sensitivity of ultrasonography for detecting tear size in the medial-lateral dimension was 83% (95% confidence interval, 69% to 93%), and that of magnetic resonance imaging was 88% (95% confidence interval, 74% to 96%) (p = 0.41). Conclusions A well-trained office staff and an experienced orthopaedic surgeon can effectively utilize ultrasonography, in conjunction with clinical examination and a review of shoulder radiographs, to accurately diagnose the extent of rotator cuff tears in patients suspected of having such tears. Errors in diagnosis made on the basis of ultrasonography most often consist of an inability to distinguish between partial and full-thickness tears that are approximately 1 cm in size. In this study, such errors did not significantly affect the planned surgical approach. Level of Evidence Diagnostic Level I. See Instructions to Authors for a complete description of levels of evidence.

Rupture may occur in up to 30% of silicone breast implants, with the rate varying by implant age and type [1]. When ruptured implants are surgically removed, removal of any extravasated silicone is also attempted. Free silicone remaining in the breast may cause discomfort on be detected as a palpable mass. Because silicone is clean, it may not be readily visible at surgery. Moreover, when silicone infiltrates the surrounding breast, muscle, on lymphatic tissue, it may not be seen as a distinct mass at the time of implant removal. Sonognaphy can detect and localize areas of free silicone that have extnavasated from ruptured implants [2-5]. We present our experience with the use of intraoperative sonography for the localization of free silicone for surgical removal or biopsy.