High intensity focused ultrasound: surgery of the future?

For 50 years, high intensity focused ultrasound (HIFU) has been a subject of interest for medical research. HIFU causes selective tissue necrosis in a very well defined volume, at a variable distance from the transducer, through heating or cavitation. Over the past decade, the use of HIFU has been investigated in many clinical settings. This literature review aims to summarize recent advances made in the field. A Medline-based literature search (1965-2002) was conducted using the keywords "HIFU" and "high intensity focused ultrasound". Additional literature was obtained from original papers and published meeting abstracts. The most abundant clinical trial data comes from studies investigating its use in the treatment of prostatic disease, although early research looked at applications in neurosurgery. More recently horizons have been broadened, and the potential of HIFU as a non-invasive surgical tool has been demonstrated in many settings including the treatment of tumours of the liver, kidney, breast, bone, uterus and pancreas, as well as conduction defects in the heart, for surgical haemostasis, and the relief of chronic pain of malignant origin. Further clinical evaluation will follow, but recent technological development suggests that HIFU is likely to play a significant role in future surgical practice.     

What is the complementary role of ultrasound evaluation in the diagnosis of acute appendicitis after CT?

The objective of our study was to estimate the complementary role of ultrasound evaluation in the diagnosis of acute appendicitis after abdominoplevic CT. A total of 104 patients initially underwent abdominopelvic CT before appendix US due to acute abdominal pain. All CT examinations were evaluated retrospectively for the presence of acute appendicitis. The findings of appendix on CT were classified into five categories (definite appendicitis, probably appendicitis, equivocal CT findings for diagnosis of appendicitis, probably not appendicitis, and normal looking appendix). Appendix US images and their radiologic reports were also evaluated retrospectively. Then, CT and US findings were correlated with clinical or pathologic diagnosis. Three all patients with definite appendicitis initially on CT again showed US findings of appendicitis. In the 32 patients of probably appendicitis on CT, US showed normal looking appendix in seven patients (21.8%, 7 of 32) who improved with medical treatment and discharged. In the 16 patients of equivocal CT findings for diagnosis of appendicitis, US showed appendicitis in seven patients (43.8%, 7 of 16) and normal looking appendix in nine patients. In the 12 patients of probably not appendicitis on CT, US showed acute appendicitis in two patients (16.7%, 2 of 12). In the 41 patients of normal looking appendix on CT, US showed acute appendicitis in five patients (12.2%, 5 of 41). US reevaluation enables us to avoid misdiagnosis of appendicitis on CT and improve diagnostic accuracy of acute appendicitis.     

Does MRI add to ultrasound in the assessment of disorders of sex development?

Objective

The objective of the study was to evaluate the need of magnetic resonance imaging and using different approaches (transabdominal, endoluminal and transperineal) in the proper assessment of disorders of sex development regarding gonadal detection and gender differentiation.

Subjects and methods

Twenty five patients with abnormalities of sex disorders were included. They were classified into two groups according to the time of clinical presentation: Group 1 (early onset) included eight cases. Their age ranged from one month to 12 years (mean age = 3.0). They presented with overt genital ambiguity of clitoral hypertrophy in a phenotypic female, non palpable testes or micropenis in a phenotypic male. Group 2 (late onset) included 17 cases. Their age ranged from 16 to 33 years (mean age 18.1). This group presented by distressing puberty symptoms of primary amenorrhea in a female phenotype or undescended testis and behaving as a male. Cases were subjected to Ultrasound and MR imaging examinations. Imaging results were correlated results of chromosomal and hormonal assays as well as laparoscopy findings.

Results

The study included: 10/25 cases (40%) of female pseudo-hermaphroditism, 13/25 cases (52%) of male pseudo-hermaphroditism, one case (4%) of true hermaphroditism and one case (4%) of pure gonadal dysgenesis. The accuracy of multi approach ultrasound was 89.8% compared to 85.7% in MR imaging.

Conclusion

Ultrasound should be considered the initial screening modality in the assessment of developmental sex disorders. MRI examination could be reserved for gonad identification when ultrasound examination fails to do so and for corrective surgery guidance.     

Does the phase of menstrual cycle affect MR-guided focused ultrasound surgery of uterine leiomyomas?

PURPOSE: To determine whether the phase of menstrual cycle at the time of MR-guided focused ultrasound surgery (MRgFUS) treatment for uterine leiomyomas affects treatment outcome. METHODS: We enrolled all patients participating in a prospective phase III clinical trial from our center who completed 6 months of clinical and imaging follow-up. Patients with irregular cycles and those on oral contraceptives were excluded. Data prospectively documenting the date of the last menstrual period (LMP) at the time of treatment, length and duration of cycle, and raw symptom severity score (SSS) from the Uterine Fibroid Symptom and Quality of Life questionnaire, at baseline and 6 months were collected. Proliferative phase patients were determined retrospectively as those who were treated within less than 14 days from LMP; secretory phase patients were classified as those who were treated greater than 14 days from LMP. RESULTS: A total of 58 patients were enrolled. There was no significant difference in the mean SSS at baseline and mean SSS at 6 months between patients treated in the proliferative versus secretory phase of the cycle. No significant difference in the SSS change from baseline to 6 months was seen between the two groups. CONCLUSIONS: Menstrual cycle phase does not influence MRgFUS treatment outcome. Symptomatic improvement occurs with treatment during either phase of the menstrual cycle. Thus, the scheduling of MRgFUS treatment need not be based upon the phase of the menstrual cycle.     

Waldenstr?m's macroglobulinaemia of the breast detected by colour Doppler ultrasound.

Waldenstr?m's macroglobulinaemia (lymphoplasmacytoid lymphoma) is a low grade B cell non-Hodgkin's lymphoma. The majority of patients present with advanced disease. Lymphoma of the breast is rare and usually arises as part of a disseminated disease process. A case of disseminated Waldenstr?m's macroglobulinaemia is reported in which the breast was involved. The findings using standard mammographic and ultrasound techniques were non-specific and only when colour Doppler examination was performed could an abnormality be detected.     

Preoperative assessment of stenosis of the epiaortic vessels: can colour-Doppler ultrasound really supplant angiography?

PURPOSE: To evaluate the diagnostic role of digital angiography compared with colour-Doppler US in the study of epiaortic vessel stenoses and the degree of morbidity associated with angiography. MATERIALS AND METHODS: Out of 2,000 angiographic examinations of the epiaortic vessels performed for the concurrent presence of clinical findings of cerebrovascular insufficiency and colour-Doppler US findings of carotid-vertebral stenosis, a randomized sample of 200 patients was evaluated. The retrospective review of medical records provided the surgical data of the stenosis which were subsequently compared with the angiography and colour-Doppler US findings, and with the clinical and laboratory data to identify the possible complications of angiography. RESULTS: Diagnostic agreement was 75%. Colour-Doppler US underestimated stenosis in 16.5% and overestimated stenosis in 8% of cases. In 18% of cases there was a diagnostic gain of angiography (vascular lesions associated with main lesion), which also provided clinically important incidental findings (intracranial aneurysms, meningiomas) in 6.5% of patients. No relevant complications resulting from the angiographic procedure were recorded. CONCLUSIONS: Angiography allowed a more accurate evaluation of the degree of stenosis compared with colour-Doppler ultrasound. Moreover, it allowed diagnosis of important associated conditions that may affect therapeutic planning. In our series, we recorded no important complications related to angiography. Therefore, angiography remains the standard of reference in the preoperative evaluation of patients with clinically diagnosed cerebral ischaemia. Though fairly reliable as a first-line investigation, Colour-Doppler US is not sufficiently exhaustive as a pre-operative evaluation tool.     

Correlations between the time–intensity parameters of contrast-enhanced ultrasound and clinical prognosis of hepatocellular carcinoma

PurposeThe purpose of the study was to detect the correlation between the time–intensity parameters of contrast-enhanced ultrasound (CEUS) and the clinical prognosis of hepatocellular carcinoma (HCC).MethodsA total of 73 HCC patients were analyzed with the time–intensity curve of CEUS. The expression of vascular endothelial factor (VEGF) and CD34 in different differentiation-staged HCC specimens was observed using immunohistochemistry.ResultsA positive correlation was found between the VEGF expression and microvessel density. The time–intensity parameters were not correlated with the HCC size.ConclusionsCEUS time–intensity parameters are inducive for assessing the prognosis of HCC with revealed intratumoral microvessel perfusion in different differentiation stages.     

Can the effects of exercise on bone quality be detected using the CUBA clinical ultrasound system?

OBJECTIVES: To determine whether the CUBA clinical quantitative ultrasound bone analyser was able to distinguish variations in bone quality between groups categorised according to activity level. METHOD: Eighty one white women aged 32 to 89 completed a confidential questionnaire on general health, diet, and exercise participation and underwent ultrasound testing at the right calcaneus utilising a CUBA clinical ultrasound system. RESULTS: The results confirmed the inverse relationship between age and the ultrasound indicators of bone quality: broadband ultrasound attenuation (BUA) (r = -0.52) and velocity of sound (VOS) (r = -0.68). Subject height weakly but significantly correlated with BUA (r = 0.39) and VOS (r = 0.35), and subject weight only correlated significantly with BUA (r = 0.37). Activity level was significantly associated (p < 0.05) with the changes in ultrasound attenuation (BUA). The use of hormone replacement therapy or the contraceptive pill, a family history of osteoporosis, and gross indicators of calcium consumption did not yield significant results. CONCLUSION: Data obtained from the CUBA clinical system were sensitive enough to allow women to be classified into groups according to activity level. These data were within the range of "normal" ultrasound data and hence it is suggested that the machine has research as well as clinical value.     

How does the blood leave the brain? A systematic ultrasound analysis of cerebral venous drainage patterns

The internal jugular veins are considered to be the main pathways of cerebral blood drainage. However, angiographic and anatomical studies show a wide anatomical variability and varying degrees of jugular and non-jugular venous drainage. The study systematically analyses the types and prevalence of human cerebral venous outflow patterns by ultrasound and MRI. Fifty healthy volunteers (21 females; 29 males; mean age 27±7 years) were studied by color-coded duplex sonography. Venous blood volume flow was measured in both internal jugular and vertebral veins in the supine position. Furthermore, the global arterial cerebral blood volume flow was calculated as the sum of volume flows in both internal carotid and vertebral arteries. Three types of venous drainage patterns were defined: a total jugular volume flow of more than 2/3 (type 1), between 1/3 and 2/3 (type 2) and less than 1/3 (type 3) of the global arterial blood flow. 2D TOF MR-venography was performed exemplarily in one subject with type-1 and in two subjects with type-3 drainage. Type-1 drainage was present in 36 subjects (72%), type 2 in 11 subjects (22%) and type 3 in 3 subjects (6%). In the majority of subjects in our study population, the internal jugular veins were indeed the main drainage vessels in the supine body position. However, a predominantly non-jugular drainage pattern was found in approximately 6% of subjects.This study was presented in part as an oral presentation at the 8th Meeting of Neurosonology and Hemodynamics, Alicante, Spain, 18–21 May 2003.     

Detection of ileocecal Crohn’s disease using ultrasound as the primary imaging modality

At our hospital ultrasound (US) is used as an initial screening procedure in all patients with abdominal symptoms. The purpose of this study was to assess the effect of this policy on the detection of ileocecal Crohns disease. We retrospectively studied all patients with a new diagnosis of ileocecal Crohns disease from our institute over the period 1990–2001. The final diagnosis was based on clinical follow-up and pathological, surgical, US, and other radiological findings. We noted who referred the patient to the radiology department, what the initial clinical presumption was, and what the first imaging study was. US diagnoses were determined from the initial US report and US findings were registered from the images. There were a total of 47 patients (20 men, 27 women) with a mean age of 30 years and a median age of 27 years (range 14–75 years). In all patients the initial imaging study was an abdominal US. Using US, a confident diagnosis of ileocecal Crohns disease was made in 35 of the 47 patients, Crohns disease was suggested among the differential diagnosis in 10, and an incorrect diagnosis was made in 2 patients. In 28 of 47 patients, the referring physician did not consider Crohns disease when requesting the initial US examination. In eight patients with appendicitis-like symptoms, the US findings strongly influenced the decision to refrain from operation at that point in time. US, when used as a low-threshold diagnostic procedure, is a reliable and noninvasive means for making an early diagnosis of ileocecal Crohns disease in patients who present with atypical symptoms. It may prevent both unnecessary therapeutic delay as well as unnecessary surgery.     

Prefraction displacement and intrafraction drift of the prostate due to perineal ultrasound probe pressure

Objective

In image-guided EBRT of the prostate, transperineal ultrasound (US) probes exert pressure on the perineum both during planning and treatment. Through tissue deformation and relaxation, this causes target and risk organ displacement and drift. In this study, prefraction shift and intrafraction drift of the prostate are quantified during robotic transperineal 4DUS.

Methods

The position of the prostate was recorded for different positions of the probe before treatment in 10 patients (16 series of measurements). During treatment (15 patients, 273 fractions), intrafraction motion of the prostate was tracked (total of 27?h and 24?min) with the transperineal probe in place.

Results

Per 1?mm shift of the US probe in the cranial direction, a displacement of the prostate by 0.42 ± 0.09?mm in the cranial direction was detected. The relationship was found to be linear (R² = 0.97) and highly significant (p < 0.0001). After initial contact of the probe and the perineum (no pressure), a shift of the probe of about 5–10?mm was typically necessary to achieve good image quality, corresponding to a shift of the prostate of about 2–4?mm in the cranial direction. Tissue compression and prostate displacement were well visible. During treatment, the prostate drifted at an average rate of 0.075?mm/min in the cranial direction (p = 0.0014).

Conclusion

The pressure applied by a perineal US probe has a quantitatively similar impact on prostate displacement as transabdominal pressure. Shifts are predominantly in the cranial direction (typically 2–4?mm) with some component in the anterior direction (typically <1?mm). Slight probe pressure can improve image quality, but excessive probe pressure can distort the surrounding anatomy and potentially move risk organs closer to the high-dose area.

     

Real-time ultrasound elastography: Does it improve B-mode ultrasound characterization of solid breast lesions?

Introduction

Elastography is a non-invasive medical imaging technique that detects tumors based on their stiffness (elasticity). Strain images display the relative stiffness of lesions compared with the stiffness of surrounding tissue as cancerous tumors tend to be many times stiffer than the normal tissue, which “gives” under compression. An image in which different degrees of stiffness show as different shades of light and dark is called an elastogram.

Purpose

To prospectively evaluate the sensitivity and specificity of the real-time sonoelastography as compared with B-mode US for distinguishing between benign and malignant solid breast masses. The density of the glandular breast tissue was taken in consideration in addition to the Breast Imaging Reporting and Data System (BI-RADS) categories of the lesions, with biopsy results as the reference standard.

Methods

A total of 216 candidate solid lesions (123 benign and 93 malignant) in 188 patients were examined with 2-dimensional ultrasonography, elastosonography and mammography (for 147 patients). The lesions were classified according to the density of the glandular breast tissue into low density group (D1) and a high density group (D2) and were categorized with the BIRADS score. Elastographic images were assigned an elasticity score of 1 to 5 (1–3, benign; 4 and 5, malignant) according to the Multi-Center Team of Study and the strain ratios of the lesions were measured. Concordance between the imaging findings and histopathologic results was documented. Statistical analysis was performed and sensitivity, specificity and positive and negative predictive values for both elastography and conventional sonography were calculated.

Results

Elastography showed less sensitivity but higher specificity than conventional sonography in the differentiation of benign from malignant solid lesions: B-mode sonography had sensitivity of 85.1%, specificity of 93.9%, a positive predictive value of 92.5% and a negative predictive value of 87.8%, compared with the sensitivity of 80.1%, specificity of 97.1%, a positive predictive value of 96.8% and a negative predictive value of 82.1% for elastography. Elastography was superior to B-mode US in diagnosing solid lesions in the low density group (D1) (96.6% vs. 92.4% specificity) and less in the dense glandular tissue (97.8% vs. 95.9% specificity).

Conclusions

Real-time sonoelastography is an useful technique for the characterization of benign and malignant solid lesions as it increases the diagnostic specificity comparable to B-mode ultrasound, particularly in both ACR 1 and 2, thus reducing the false-positive rate.     

Chest ultrasound in the assessment of patients in ICU: How can it help?

Background: Different imaging techniques can be used for assessment of chest problems in ICU patients, however ultrasound is a good diagnostic tool giving more information and at the same time without exposure to radiation and without risk of critical patient transfer.Aim of the work: The aim of this work was to study the role of thoracic ultrasound in assessment of ICU patients.Materials and methods: The study was carried out on 30 patients admitted to the ICU.B and M modes chest ultrasound was done for all patients using EsaoteMyLab?Alpha with eHD Technology.Results: The study included 19 males and 11 females with mean age of 42.6 ± 21.4 years. In this study ultrasound was able to diagnose Pneumothorax: 3 cases (10%). Pleural effusion: 20 cases (66.6%). Alveolar interstitial syndrome: 7 cases (23.3%). Lung consolidation: 20 cases (66.6%). Pulmonary infarcts: 1 case (3.3%). Neoplastic disease: 1 case (3.3%). Chest wall pathology: 1 case (3.3%).Conclusion: Ultrasound examination of the chest is a non- invasive, and promising bed side tool for examination of ICU patients.     

Imaging the premature brain: ultrasound or MRI?

Neuroimaging of preterm infants has become part of routine clinical care, but the question is often raised on how often cranial ultrasound should be done and whether every high risk preterm infant should at least have one MRI during the neonatal period. An increasing number of centres perform an MRI either at discharge or around term equivalent age, and a few centres have access to a magnet in or adjacent to the neonatal intensive care unit and are doing sequential MRIs. In this review, we try to discuss when best to perform these two neuroimaging techniques and the additional information each technique may provide.