Detection of bleeding in injured femoral arteries with contrast-enhanced sonography

Contrast-enhanced ultrasonography (CEUS) reveals active bleeding into an abdominal hematoma in a patient with ongoing subcutaneous injections

A 95-year-old woman with metastasizing bronchial carcinoma presents with left inguinal pain. The referring physician would like to exclude an inguinal hernia and a deep vein thrombosis due to her precondition of essential thrombocythemia. Conventional ultrasound excluded the presence of a deep vein thrombosis yet showed a 6 cm × 5 cm hematoma distal of the left m. rectus abdominis. The subsequently performed color Doppler examination excluded a pseudoaneurysm but could not preclude active bleeding. Eventually, CEUS showed contrast-pooling within the hematoma as a sign of active extravasation, suggesting ongoing bleeding.

Technological Advances in Diagnostic Imaging in Exotic Pet Medicine

Diagnostic imaging relies on interpretation of interactions between the body tissue and various energies, such as x-rays, ultrasound, and magnetic or nuclear energies, to differentiate normal from abnormal tissues. Major technological improvements regarding emission and detection of the energetic waves, as well as reconstruction and interpretation of the images, have occurred. These advances made possible visualization of smaller structures, quantitative evaluation of functional processes, and development of unique imaging-guided procedures. This article reviews the technological advances that allowed development of cone beam computed tomography, dual-energy x-ray absorptiometry, and contrast-enhanced ultrasonography, which all could have applications in exotic pet medicine.

Contrast-enhanced ultrasonography of post-interventional hematoma: the bleeding mushroom is growing inside

Catheter ablation is an effective treatment in patients with symptomatic atrial fibrillation. Complications are infrequent and usually resolve with minimal or no intervention, but active bleeding due to arterial injury during the vascular access can sometimes represent a life-threatening complication. Contrast-enhanced computed tomography is the standard technique to detect active bleeding, but it may not be immediately available. We report a case of iatrogenic hemorrhage after catheter ablation, in which contrast-enhanced ultrasonography played a decisive role in the recognition of active arterial bleeding due to injury to the right common femoral artery.

The use of contrast-enhanced ultrasonography for the detection of active renal hemorrhage in a dog with spontaneous kidney rupture resulting in hemoperitoneum

OBJECTIVE

To describe the use of contrast-enhanced ultrasonography (CEUS) for the detection of active renal hemorrhage in a dog with spontaneous kidney rupture resulting in hemoperitoneum.

CASE SUMMARY

A 9-month-old, sexually intact male Boxer dog presented for acute collapse, abdominal pain, and tachycardia. Physical examination findings were consistent with hypovolemia and acute abdomen. B-mode ultrasonography revealed peritoneal effusion and a right kidney mass. Subsequently, a CEUS study was performed on the right kidney, which demonstrated active hemorrhage from that kidney resulting in both hemoretroperitoneum and hemoperitoneum. At exploratory surgery, ultrasonographic findings were confirmed and a right nephrectomy was performed. Histopathology demonstrated severe parenchymal alterations along with the presence of nematode larvae. Fecal and urine testing for the presence of parasitic ova were negative. Identification of the larvae was inconclusive. At 30 days postoperatively, repeat B-mode ultrasound and clinicopathologic testing was unremarkable. The dog was alive at 1 year postsurgery with no ill effects.

NEW OR UNIQUE INFORMATION PROVIDED

To the authors' knowledge, this is the first report of CEUS for the detection of active hemorrhage from a kidney resulting in hemoretroperitoneum and hemoperitoneum in a dog. Although rare, the finding of nematode larvae within the renal parenchyma may have been the cause of kidney rupture. Importantly, surgical removal of the kidney was curative. Benign processes causing kidney rupture such as parasitic infestation should be considered in the working diagnosis as related to geographical location.

Massive haematoma formation associated with proximal popliteal artery haemangioendothelioma in a dog

A mixed breed dog presented with diffuse unilateral hind limb swelling, which ultrasound and cytology confirmed to be caused by severe haematoma formation. Multi-detector computed tomography (MDCT) angiography allowed distinct visualisation of an anomalous segment of the proximal popliteal artery, the presumed origin of the self-sustaining haematoma. Histopathology classified the malformed vessel as a haemangioendothelioma, a neoplasia of intermediate malignancy. Considering this as differential diagnosis to a neoplastic vascular alteration of high malignancy (such as haemangiosarcoma) might alter choice of treatment in future cases with similar clinical and imaging findings.

Focused assessment with sonography for trauma: methods, accuracy, and indications

Focused assessment with sonography for trauma (FAST) is an invaluable adjunct in the management of trauma patients for detection of free intra-abdominal and pericardial fluid. Over the past 2 decades, the use of this technique has increased significantly. This article reviews the clinical application and future direction of FAST.

Detection and localization of peripheral vascular bleeding using Doppler ultrasound

BACKGROUND

Hemorrhage from wounds in the extremities is the leading cause of preventable death on the battlefield. To successfully treat these injuries, the exact source of bleeding must be localized.

OBJECTIVE

The purpose of this study was to determine the feasibility of using Doppler ultrasound to precisely detect and localize peripheral vascular bleeding.

METHODS

Injuries were produced in common femoral arteries (diameter of ∼5 mm) of 28 pigs in vivo. Single puncture injuries were produced using 6 French (F) (n = 10), 9 F (n = 22), and 12 F (n = 12) catheters. In addition, multiple punctures were made (using 6 F and 9 F catheters) in eight common femoral arteries to simulate bleeding from multiple injuries. Finally, laceration injuries were produced using a scalpel in 10 femoral vessels.

RESULTS

In color Doppler images, bleeding was observed as a turbulent jet flow originating from the injury site in the vessel. This jet flow had checkered red-blue color pattern at the bleeding site, as opposed to a uniform color pattern in an intact artery. Peak systolic velocity at the injury site, measured using pulsed Doppler, was elevated to up to 152.0 ± 81.6 cm/s, as compared to 78.8 ± 17.5 cm/s in normal arteries. Further, end diastolic velocity increased from 6.1 ± 4.9 cm/s before the injury to up to 59.1 ± 33.1 cm/s after the injury. Resistance index was significantly lower (0.6 for 9 F and 12 F punctures, and 0.8 for 6 F punctures) at the bleeding site in injured arteries as compared to the resistance index of intact arteries (of 0.9).

CONCLUSION

Our results showed a characteristic change in the systolic and diastolic velocities, as well as resistance indices at the injury site in peripheral arteries. These findings may serve as groundwork for development of automated bleeding detection and localization methods, and facilitate various hemorrhage control treatments.

Tissue vibration pulsatility for arterial bleeding detection using Doppler ultrasound

Trauma is the number one cause of death among Americans between 1 and 44 years old, and exsanguination due to internal bleeding resulting from arterial injuries is a major factor in trauma deaths. We have evaluated the feasibility of using tissue vibration pulsatility in arterial bleeding detection. Eight femoral arteries from four juvenile pigs were punctured transcutaneously with a 6 or 9-French catheter. Also, 11 silicone vessels wrapped with turkey breast were placed in a pulsatile flow phantom and penetrated with an 18-gauge needle. The tissue vibration pulsatility was derived as a ratio of the maximum spectral energy from 200 to 2500 Hz of tissue vibration in systole over a baseline value in diastole. Then, the tissue vibration pulsatility index (TVPI) was defined as the maximum tissue vibration pulsatility value for each experimental condition. Both in vitro and in vivo results showed that the TVPI from injured vessels is significantly higher (p<0.005) than that of intact vessels. In addition, we constructed the 2D map of tissue vibration pulsatility during in vitro studies and found that it could be used for spatial localization of the puncture site. Our preliminary results indicate that the tissue vibration pulsatility may be useful for detecting arterial bleeding and localizing the bleeding site.

Pulsatile flow phantom for ultrasound image-guided HIFU treatment of vascular injuries

A pulsatile flow phantom was developed for studies of ultrasound image-guided high intensity focused ultrasound (HIFU) application in transcutaneous hemostasis of injured blood vessels. The flow phantom consisted of a pulsatile pump system with instrumented excised porcine carotid artery, which was imbedded in a transparent agarose gel to model structural configuration of in vivo tissues. Heparinized porcine blood was circulated through the phantom. The artery was injured using an 18-gauge needle to model a penetrating injury in human peripheral vasculature. A HIFU transducer with the diameter of 7 cm, focal length of 6.3 cm and frequency of 3.4 MHz was used to seal the puncture. Ultrasound imaging was used to localize and target the puncture site and to monitor the HIFU treatment. Triphasic blood flows present in the human arteries were reproduced, with flow rates of 50 to 500 mL/min, pulse rates of 62 to 138 beats/min and peak pressures of 100 to 250 mm Hg. The penetrating injury of an artery was mimicked successfully in the flow phantom setting and was easily visualized both optically through the transparent gel and with power Doppler ultrasound imaging. Hemostasis was achieved in 55 +/- 31 s (n = 9) of HIFU application. Histologic observations showed that a HIFU-sealed puncture was filled with clotted blood and covered with a fibrin cap. The pulsatile flow phantom provides a controlled and repeatable environment for studies of transcutaneous image-guided HIFU application in hemostasis of a variety of blood vessel injuries.

Color and pulsed Doppler sonography for arterial bleeding detection

OBJECTIVE

Hemorrhage resulting from penetrating injuries in the extremities is the leading cause of preventable death in the modern battlefield. Development of methods for detection and localization of vascular bleeding is needed that could be applied emergently without special training outside the hospital setting. Our objective was to assess whether Doppler sonography can provide quantitative parameters that characterize the bleeding site in the extremities.

METHODS

Twenty-four rabbit femoral arteries (diameter of approximately 1 mm) were punctured transcutaneously with an 18-gauge needle. Doppler interrogations were performed at 5 locations in the injured vessels (site of injury, distal and proximal locations relative to the injury, and neck and tip of the bleeding jet).

RESULTS

Compared with the normal signals obtained before the vessel was punctured, pulsed Doppler observations of the injury site showed a statistically significant increase in the systolic and diastolic velocities (systolic: mean +/- SD, 30.1 +/- 12.5 cm/s [injury] versus 15.1 +/- 4.2 cm/s [normal]; diastolic: 17.8 +/- 6.5 cm/s [injury] versus 0.7 cm/s [normal]). Similar increases in velocities were observed at the neck of the bleeding jet, whereas the tip of the bleeding jet showed venouslike patterns. These patterns are unique only at the bleeding site. Color Doppler observations showed turbulence (in the form of checkered color patterns) localized at the injury site.

CONCLUSIONS

Our results indicate that both color and pulsed Doppler sonography can be used to accurately localize the site of injury, which may facilitate application of hemorrhage control therapies in battlefield situations.

Hemorrhage control using high intensity focused ultrasound

Hemorrhage control is a high priority task in advanced trauma care, because hemorrhagic shock can result in less than a minute in cases of severe injuries. Hemorrhage was found to be solely responsible for 40-50% of traumatic civilian and battlefield deaths in recent years. The majority of these deaths were due to abdominal and pelvic injuries with hidden and inaccessible bleeding of solid organs such as liver, spleen, and kidneys, as well as major blood vessels. High intensity focused ultrasound (HIFU) offers a promising method for hemorrhage control. An important advantage of HIFU is that it can deliver energy to deep regions of tissue where hemorrhage is occurring, allowing cauterization at depth of parenchymal tissues, or in difficult-to-access anatomical regions, while causing no or minimal biological effects in the intervening and surrounding tissues. Moreover, HIFU can cause both thermal and mechanical effects that are shown to work synergistically for rapid hemorrhage control. The major challenges of this method are in development of bleeding detection techniques for accurate localization of the injury sites, delivery of large HIFU doses for profuse bleeding cases, and ensuring safety when critical structures are in the vicinity of the injury. Future developments of acoustic hemostasis technology are anticipated to be for applications in peripheral vascular injuries where an acoustic window is usually available, and for applications in the operating room on exposed organs.

Image-guided acoustic hemostasis for hemorrhage in the posterior liver

We investigated the use of ultrasound image-guided high intensity focused ultrasound (HIFU) to stop bleeding from injuries in the posterior liver. A HIFU transducer with focal length of 3.5 cm and frequency of 3.2 MHz was integrated with an intraoperative high-resolution ultrasound-imaging probe. Wedge tissue extractions, 30-mm long, 5-mm wide and 8-mm deep, were made in the posterior liver surface of five pigs to induce bleeding. The device was positioned on the anterior surface of the liver and HIFU was applied using ultrasound image-guidance. Hemostasis was achieved in 66 +/- 18 s (mean +/- standard deviation) for 17 HIFU treatments. During 7 min of sham HIFU treatment, none of the control incisions (n = 7) became hemostatic. Ultrasound image-guided HIFU offers a promising method for hemostasis in surgical settings in which the hemorrhage site is hidden and/or not accessible.