Ultrasonographic Modalities to Assess Vascular Anatomy and Disease

Arterial tree anomalies in patients with clubfoot: an investigation carried out at Soba University Hospital

Vascular deficiencies and reduced perfusion of the anterior tibial artery and the dorsalis pedis artery were suggested as causes of congenital talipes equino varus (CTEV). In this study, we assessed the prevalence of arterial abnormalities in patients with CTEV (50 patients; 74 feet) compared with a normal control group (16 patients; 32 feet) by Doppler ultrasound and Ankle Brachial Index. The flow was normal in the control group and was deficient in 39.19% of clubfoot patients. In severe clubfoot cases, the deficiency was found to an extent of 76.67%. In conclusion, the anterior tibial artery and dorsalis pedis artery are deficient in CTEV patients; to avoid postoperative skin sloughing, arterial supply must be protected using a judicious incision.

Role of contrast-enhanced ultrasound arterial mapping in surgical planning for patients with critical limb ischemia

The goal of the study described here was to evaluate the role of contrast-enhanced ultrasound (CEUS) arterial mapping in surgical planning in cases of critical limb ischemia. From March 2007 to December 2012, 565 consecutive patients with critical limb ischemia of the lower limbs were treated and initially examined with only ultrasound (US) arterial mapping. For 479 of the 565 patients, basic US examination results were deemed sufficient for surgical planning (group A). That is, US examination provided sufficient information to decide a surgical plan to treat those patients. In the remaining 86 patients, basic US examination was insufficient for revascularization planning, and CEUS examination was performed (group B). In 5 cases, CEUS results were also insufficient for surgical planning, as a suitable outflow vessel was not visualized. In these cases, a pre-operative arteriogram was performed. To assess the usefulness of CEUS, we compared results of examinations with and without contrast administration, surgical findings and angiographic findings when available. Data were collected prospectively. Examinations were compared by establishing the degree of agreement between results of paired examinations and degree of agreement between CEUS results and surgical findings. Clinical, hemodynamic (ankle-brachial index) and duplex follow-up was performed at 1 and 3 mo to evaluate cumulative patency of the procedures in each group. Within group B, degree of agreement between basic US and CEUS was 46.5%. CEUS resulted in a change in the surgical plan in 46 of 86 patients. Among all 565 patients, degree of agreement between surgical decision based on basic ultrasound arterial mapping and final decision based on surgical findings was 87.1%, and improved to 95.2% with CEUS (p = 0.00001, κ index = 0.823). Degree of agreement between the ultrasound-based decision and surgical findings was 97.5% in group A (κ index = 0.818) and 94.2% in group B (κ = 0.848). There was no significant difference between groups (p = 0.784). Within group B, of the five arteriograms performed, results of only one matched well the US mapping findings. Vessel patency at 1 and 3 mo did not significantly differ between patients whose surgical planning was based on basic US and patients whose planning was based on CEUS (p = 0.418 and p = 0.489, respectively). US arterial mapping is an excellent tool for surgical planning in critical limb ischemia. CEUS arterial mapping improves the accuracy of ultrasound examination in patients with critical limb ischemia, especially in patients with inconclusive non-enhanced exams.

Ultrasound evaluation of common carotid artery blood flow in the Labrador retriever

Background

Doppler ultrasound (DUS) examination provides quantitative and qualitative information concerning the blood flow in veins and arteries, enabling their morphological evaluation and the collection of hemodynamic data. Dogs and cats as well as humans may display neurological signs of brain hypoperfusion secondary to common carotid alterations. Hence, DUS examination might aid in the differential diagnosis of neurological disorders of ischemic origin, among other causes. The objective of this study was to register normal values for systolic peak velocity, minimum diastolic velocity, diameter and resistance index of both common carotid arteries of 12 healthy Labrador retriever dogs between 2 and 5 years of age. By gathering these values, we might be able to improve the sensitivity of hemodynamic studies in clinically important brain disorders.

Results

There were no statistical differences between the values for the right and left vessels: the systolic peak velocity was 75.8 ± 16 cm/s, minimum diastolic velocity was 12.2 ± 4 cm/s, common carotid diameter was 0.545 ± 0.063 cm, and resistance index was 0.83 ± 0.07.

Conclusions

The results of this study might be used to establish normal parameters for Labrador retriever dogs and thus help in the diagnosis of neurological disorders associated with alterations of the carotid arteries. Similar studies must be performed to evaluate the same parameters in other dog breeds of different sizes and skull conformations.

MRI of atherosclerosis: diagnosis and monitoring therapy

Atherosclerosis is a prevalent disease affecting millions of Americans. Despite our advances in diagnosis and treatment, atherosclerosis is the leading cause of death in America. High-resolution magnetic resonance imaging has overcome the limitations of current angiographic techniques and has emerged as a leading noninvasive imaging modality for atherosclerotic disease. Atherosclerosis of the arterial wall of the human carotid, aortic, peripheral and coronary arteries have all been successfully evaluated. In addition, the power of magnetic resonance imaging to differentiate the major components of atherosclerotic plaque has been validated. The ability to image the vessel wall and risk stratify atherosclerotic plaque will create management decisions not previously faced, and has the potential to change the way atherosclerosis is treated.

Functional correlates of Doppler flow study of the female urethral vasculature

OBJECTIVES

To examine the effect of individual patient factors (age, parity, body mass index, menstrual cycle, menopause, hormone replacement therapy, bladder neck position and urethral mobility) on the appearance of Doppler flow in urethral vessels, to investigate the association between the Doppler flow parameters and intrinsic urethral function, storage and voiding, and to explore differences in the urethral vasculature between subjects with and without urodynamic stress incontinence (USI).

METHODS

Over a 4-year period we prospectively performed imaging studies in 355 women, including 244 who denied any lower urinary tract symptoms within the previous 3 months (Group A) and 111 who had had lower urinary tract symptoms (Group B). Studies included morphologic assessment and Doppler flow investigation of the lower urinary tract. Vascular flow velocity and vessel density in the urethral vasculature were measured. For women in Group B, multichannel urodynamic studies were also performed.

RESULTS

The urethral vasculature has five main branches of vessels. Their appearance was not affected by the menstrual cycle or menopause except for those of the anterior vaginal vessel and anterior branch of the middle urethral vessel. Other than that of the posterior urethral vessel, in which there was a correlation with parity, the resistance index (RI) was not affected by individual patient factors. However, there was a correlation between the vascular index (VI) and individual factors such as age (r = -0.336, P = 0.002), body mass index (r = -0.287, P = 0.028), menopause (r = -0.402, P < 0.001), and hormone replacement therapy (r = 0.392, P = 0.027). Only the VI and RI of the posterior urethral vessel correlated significantly with the urethral pressure profile. In subjects with lower urinary tract symptoms, the appearance of the urethral vasculature on power Doppler imaging and the corresponding RI and VI values were not correlated with objective evidence of USI.

CONCLUSION

Patient factors may affect specific Doppler flow parameters of the urethral vasculature, which are related to intrinsic resting urethral closure. There is no difference in the appearance of the urethral vasculature in subjects with or without USI.

Quantitative Vascular Measurements in Arterial Occlusive Disease

Accuracy in quantifying arterial occlusive disease requires an understanding of the relevant technical considerations and familiarity with the strengths and weaknesses of various imaging modalities in this setting. The degree of stenosis is evaluated in terms of diameter stenosis, which can be measured on either projection images or cross-sectional images, or area stenosis, which can be measured only on cross-sectional images. With projection images, the minimum luminal diameter should be sought on multiple images obtained at different angles. The reference site used for measurement should be noted and may be located at the level of the lesion or in a normal-looking portion of the stenotic vessel near the lesion. Multi-detector row computed tomographic (CT) angiography and magnetic resonance (MR) angiography are starting to replace digital subtraction angiography in quantifying arterial occlusive disease. CT angiography allows accurate evaluation without reducing in-plane resolution, although beam-hardening artifacts from high-attenuation structures can degrade image quality. MR angiography is useful even in cases of severe calcification but has a lower spatial resolution. Ultrasonography (US) may also be helpful in quantifying arterial occlusive disease; US analysis is almost always based on blood flow velocity measurement. Precise measurements of stenotic occlusion will help determine optimal therapy for affected patients.

Magnetic resonance imaging of atherosclerosis

Abundant data now link composition of the vascular wall, rather than the degree of luminal narrowing, with the risk for acute ischemic syndromes in the coronary, central nervous system, and peripheral arterial beds. Over the past few years, magnetic resonance angiography has evolved as a well-established method to determine the location and severity of advanced, lumen-encroaching atherosclerotic lesions. In addition, more recent studies have shown that high spatial resolution, multisequence MRI is also a promising tool for noninvasive, serial imaging of the aortic and carotid vessel wall, which potentially can be applied in the clinical setting. Because of the limited spatial resolution of current MRI techniques, characterization of coronary vessel wall atherosclerosis, however, is not yet possible and remains the holy grail of plaque imaging. Recent technical developments in MRI technology such as dedicated surface coils, the introduction of 3.0-T high-field systems and parallel imaging, as well as developments in the field of molecular imaging such as contrast agents targeted to specific plaque constituents, are likely to lead to the necessary improvements in signal to noise ratio, imaging speed, and specificity. These improvements will ultimately lead to more widespread application of this technology in clinical practice. In the present review, the current status and future role of MRI for plaque detection and characterization are summarized.