Role of ultrasound in medical management of patients with renal stone disease

Eighty-three patients with radiographically opaque renal stones were evaluated prospectively with ultrasound and compared to KUB (kidneys, ureters, bladder) with tomograms (KUB/T) to further define the use of ultrasound in the evaluation of renal calculi. The presence or absence and the size, number, and location of stones were analyzed and correlated for each modality. Ultrasound detected the presence of renal stones in 77 of 83 (93%) patients. However, all of the stones were detected on ultrasound in only 60% of these patients. Thirty percent (80 of 269) of the papillary-calyceal stones seen on KUB/T were missed on US; 66% of the stones missed measured 2 mm or less. Although ultrasound can be used for detection of intrarenal stones, KUB/T is a more accurate imaging examination for determination of size and number of small stones.     

Value of mammography and combined grey scale ultrasound and ultrasound elastography in the differentiation of solid breast lesions

Aim of the work

The aim of this work was to evaluate the value of ultrasound elastography (UE) in differentiating benign versus malignant solid breast lesions discovered in mammography and compare it with grey scale ultrasound (US) and mammography.

Methods

From May 2011 to May 2013, 114 solid lesions from 100 consecutive patients discovered during mammography were categorized into benign or malignant by mammography and US and further analyzed with UE. The diagnostic results of the cases were compared with histopathologic findings.

Results

Of 114 lesions, 33 were histologically malignant, and 81 were benign. UE was the most specific (95.1%) of the 3 modalities. The accuracy (81.7%) of UE was equal to mammography and was higher than those of US (82.5% and 71.9%, respectively). A combination of UE and US had the best sensitivity (90.9%) and accuracy (93.8%).

Conclusions

Ultrasound elastography is useful for breast lesion characterization and is an easier and cheaper method and more specific than mammography or US alone, but it is operator dependent. When combined with US, detection accuracy can be greatly improved and the combination potentially could reduce unnecessary biopsy.     

Benign osteochondromas and exostotic chondrosarcomas: evaluation of cartilage cap thickness by ultrasound

Ultrasonography (US) enables accurate assessment of the cartilage cap of exostoses. The cartilage cap appears as a hypoechoic layer covering the hyperechoic surface of the calcified part. Measurements of cap thickness with US were compared with measurements performed on pathological specimens in 22 resected exostoses and 2 exostotic chondrosarcomas. The US measurements proved to be very accurate, with a mean measurement error of less than 2 mm for cartilage caps less than 2 cm thick. The detection rate and measurement accuracy of US were higher than with computed tomography (CT) and comparable to magnetic resonance imaging (MRI), which were available in 14 and 10 cases, respectively. US appears to be a good procedure for evaluating the cartilage cap, which is usually thin for a benign exostosis and thick for a malignancy. In addition, other complications — such as bursa formation — are easily recognizable. The sole limitation is that US cannot visualize the cartilage cap when it is inwardly orientated or deeply located in soft tissues, which are both, however, relatively uncommon situations.     

Localized air foci in the lower thorax in the patients with pneumothorax: Skip pneumothoraces

Purpose

To investigate the characteristics and imaging features of localized air foci in the lower thorax in patients with pneumothorax using thin-section multidetector computed tomography.

Materials and methods

Of 10,547 consecutive CT examinations comprising the chest, the CT scans of 146 patients with ordinary pneumothoraces were identified and retrospectively evaluated. The study group included 110 male and 36 female patients (mean age, 50 years; range, 1–93 years). All examinations were performed at our institution between January 2009 and December 2009. Cause of pneumothorax was classified as traumatic or non-traumatic. Localized air foci in the lower thorax were defined as being localized air collections in the lower thorax that did not appear to be adjacent to the lung. If these criteria were met, the shape, size, location laterality, and number of foci were evaluated. Associations with trauma, sex, severity of the pneumothorax, and laterality were evaluated using the χ² test. All P values <0.05 were considered significant.

Results

Localized air foci in the lower thorax presented as slit-like or small ovoid air collections in the lowest part of the pleural space. These foci were observed in 79/146 (54.1%) patients. The traumatic pneumothoraces group showed a higher prevalence of these features than the non-traumatic group. Some foci that were situated in the anterior part mimicked the appearance of free intraperitoneal air.

Conclusion

Patients with pneumothorax commonly had localized air foci in the lower thorax. Because such foci can mimic pneumoperitoneum, accurate recognition of them is required to avoid confusion with free intraperitoneal air, especially in traumatic cases.     

Sonographic Evaluation of Breast Nodules: Comparison of Conventional, Real-Time Compound, and Pulse-Inversion Harmonic Images

Objective

To compare the use of conventional, real-time compound, and pulse-inversion harmonic imaging in the evaluation of breast nodules.

Materials and Methods

Fifty-two breast nodules were included in this study, conducted between May and December 2000, in which conventional, real-time compound, and pulse-inversion harmonic images were obtained in the same plane. Three radiologists, each blinded to the interpretations of the other two, evaluated the findings, characterizing the lesions and ranking the three techniques from grade 1, the worst, to grade 3, the best. Lesion conspicuity was assessed, and lesions were also characterized in terms of their margin, clarity of internal echotexture, and clarity of posterior echo pattern. The three techniques were compared using Friedman''s test, and interobserver agreement in image interpretation was assessed by means of the intraclass correlation coefficient.

Results

With regard to lesion conspicuity, margin, and internal echotexture of the nodules, real-time compound imaging was the best technique (p < 0.05); in terms of posterior echo pattern, the best was pulse-inversion harmonic imaging (p < 0.05). Real-time compound and pulse inversion harmonic imaging were better than conventional sonography in all evaluative aspects. Interobserver agreement was greater than moderate.

Conclusion

Real-time compound and pulse-inversion harmonic imaging procedures are superior to conventional sonography in terms of both lesion conspicuity and the further characterization of breast nodules. Real-time compound imaging is the best technique for evaluation of the margin and internal echotexture of nodules, while pulse-inversion harmonic imaging is very effective for the evaluation of the posterior echo patterns.     

Potential of ultrasound in the pediatric chest

Ultrasound (US) of chest, even with inherent limitations of the US beam and air, has been useful in many pediatric chest conditions. It has extended its role and is now widely used by many subspecialists in medicine. This review article will cover techniques, indications, and applications of chest US in neonates, infants and children, including also different common as well as some rare and modern aspects and applications, such as pleural effusion, pneumothorax, pulmonary lesions, mediastinum, diaphragm, and chest wall. Other related imaging modalities are also briefly discussed.     

Unusual new signs of pneumothorax at lung ultrasound

Background

The diagnosis of pneumothorax with a bedside lung ultrasound is a powerful methodology. The conventional lung ultrasound examination consists of a step-by-step procedure targeted towards the detection of four classic ultrasound signs, the lung sliding, the B lines, the lung point and the lung pulse. In most cases, a combination of these signs allows a safe diagnosis of pneumothorax. However, the widespread application of sonographic methodology in clinical practice has brought out unusual cases which raise new sonographic signs. The purpose of this article was to introduce some of these new signs that are described after the analysis of unusual and complex cases encountered during the clinical daily practice in an emergency department.

Findings

The double lung point consists of the alternating patterns of sliding and non-sliding lung intermittently appearing at the two opposite sides of the scan. The septate pneumothorax allows B lines and lung pulse to be still visible in a condition of pneumothorax with absent sliding. In hydropneumothorax, the air/fluid border is imaged by lung ultrasound as the interposition between an anechoic space and a non-sliding A-pattern, a sign that may be named hydro-point.

Conclusions

In bedside lung ultrasound, the operator should be aware and interpret double lung point, septate pneumothorax and hydro-point. The conventional diagnostic protocol of bedside lung ultrasound for pneumothorax should be occasionally adapted to such complex cases.     

Focal Hepatic Lesions: Contrast-Enhancement Patterns at Pulse-Inversion Harmonic US using a Microbubble Contrast Agent

Objective

To analyze the contrast-enhancement patterns obtained at pulse-inversion harmonic imaging (PIHI) of focal hepatic lesions, and to thus determine tumor vascularity and the acoustic emission effect.

Materials and Methods

We reviewed pulse-inversion images in 90 consecutive patients with focal hepatic lesions, namely hepatocellular carcinoma (HCC) (n=43), metastases (n=30), and hemangioma (n=17). Vascular and delayed phase images were obtained immediately and five minutes following the injection of a microbubble contrast agent. Tumoral vascularity at vascular phase imaging and the acoustic emission effect at delayed phase imaging were each classified as one of four patterns.

Results

Vascular phase images depicted internal vessels in 93% of HCCs, marginal vessels in 83% of metastases, and peripheral nodular enhancement in 71% of hemangiomas. Delayed phase images showed inhomogeneous enhancement in 86% of HCCs; hypoechoic, decreased enhancement in 93% of metastases; and hypoechoic and reversed echogenicity in 65% of hemangiomas. Vascular and delayed phase enhancement patterns were associated with a specificity of 91% or greater, and 92% or greater, respectively, and with positive predictive values of 71% or greater, and 85% or greater, respectively.

Conclusion

Contrast-enhancement patterns depicting tumoral vascularity and the acoustic emission effect at PIHI can help differentiate focal hepatic lesions.     

Focal Hepatic Lesions: Evaluation with Contrast-Enhanced Gray-Scale Harmonic US

Objective

To determine the findings of various focal hepatic lesions at contrast-enhanced gray-scale ultrasound (US) using a coded harmonic angio (CHA) technique and emphasizing lesion characterization.

Materials and Methods

The study involved 95 patients with 105 focal hepatic lesions, namely 51 hepatocellular carcinomas (HCCs), 22 metastases, 22 hemangiomas, four cases of focal nodular hyperplasia (FNH), and six nontumorous nodules. After the injection of a microbubble contrast agent (SH U 508A), gray-scale harmonic US studies using a CHA technique were performed with a combination of continuous scanning to assess the intratumoral vasculature (vascular imaging) and interval-delay scanning to determine the sequential enhancement pattern (acoustic emission imaging). Each imaging pattern was categorized and analyzed.

Results

At vascular imaging, 69% of HCCs (35/51) showed irregular branching vessels, while in 91% of metastases (20/22) a peripherally stippled pattern was observed. Intratumoral vessels were absent in 95% of hemangiomas (21/22) and all nontumorous lesions (6/6), while in 75% of FNHs (3/4) a spoke-wheel pattern was evident. At acoustic emission imaging, 71% of HCCs (36/51) showed heterogeneous enhancement and 86% (19/22) of metastases showed rim- or flame-like peripheral enhancement during the early phase, with washout occurring in all HCCs and metastases (100%, 73/73) during the late phase. In hemangiomas, enhancement was either peripheral and nodular (19/22, 86%) or persistent and homogeneous (3/22, 14%), and 75% of FNHs (3/4) became isoechoic during the late phase.

Conclusion

At contrast-enhanced gray-scale US using a CHA technique, a period of continuous scanning depicted the intratumoral vasculature, and interval-delay scanning demonstrated the sequential enhancement pattern. The characteristic findings of various focal hepatic lesions were thus determined.     

Detection of Hepatic VX2 Tumors in Rabbits: Comparison of Conventional US and Phase-Inversion Harmonic US During the Liver-Specific Late Phase of Contrast Enhancement

Objective

To compare phase-inversion sonography during the liver-specific phase of contrast enhancement using a microbubble contrast agent with conventional B-mode sonography for the detection of VX2 liver tumors.

Materials and Methods

Twenty-three rabbits, 18 of which had VX2 liver tumor implants, received a bolus injection of 0.6 g of Levovist (200 mg/ml). During the liver-specific phase of this agent, they were evaluated using both conventional sonography and contrast-enhanced phase-inversion harmonic imaging (CE-PIHI). Following sacrifice of the animals, pathologic analysis was performed and the reference standard thus obtained. The conspicuity, size and number of the tumors before and after contrast administration, as determined by a sonographer, were compared between the two modes and with the pathologic findings.

Results

CE-PIHI demonstrated marked hepatic parenchymal enhancement in all rabbits. For VX2 tumors detected at both conventional US and CE- PIHI, conspicuity was improved by contrast-enhanced PIHI. On examination of gross specimens, 52 VX2 tumors were identified. Conventional US correctly detected 18 of the 52 (34.6%), while PIHI detected 35 (67.3%) (p < 0.05). In particular, conventional US detected only three (8.3%) of the 36 tumors less than 10 mm in diameter, but CE-PIHI detected 19 such tumors (52.8%) (p < 0.05).

Conclusion

Compared to conventional sonography, PIHI performed during the liver-specific phase after intravenous injection of Levovist is markedly better at detecting VX2 liver tumors.     

High-intensity focused ultrasound therapy: an overview for radiologists

High-intensity focused ultrasound therapy is a novel, emerging, therapeutic modality that uses ultrasound waves, propagated through tissue media, as carriers of energy. This completely non-invasive technology has great potential for tumor ablation as well as hemostasis, thrombolysis and targeted drug/gene delivery. However, the application of this technology still has many drawbacks. It is expected that current obstacles to implementation will be resolved in the near future. In this review, we provide an overview of high-intensity focused ultrasound therapy from the basic physics to recent clinical studies with an interventional radiologist's perspective for the purpose of improving the general understanding of this cutting-edge technology as well as speculating on future developments.     

Hepatic Hemangiomas: Spectrum of US Appearances on Gray-scale, Power Doppler, and Contrast-Enhanced US

Because US plays a key role in the initial evaluation of hepatic hemangiomas, knowledge of the entire spectrum of US appearances of these tumors is important. Most hemangiomas have a distinctive US appearance, and even with those with atypical appearances on conventional gray-scale US, specific diagnoses can be made using pulse-inversion harmonic US with contrast agents. In this essay, we review the spectrum of US appearances of hepatic hemangiomas on conventional gray-scale, power Doppler, and pulse-inversion harmonic US with contrast agents.     

Evaluating the role of ultrasound in chest trauma: Common complications and computed tomography comparative evaluation

Objective

to establish the role of transthoracic ultrasound as a bed-side, available, and affordable technique for imaging chest trauma patients and compared its sensitivity, specificity and accuracy for detecting chest trauma sequelae and complications to those of CT.

Evaluation of hepatocellular carcinoma using SonoVue,a second generation ultrasound contrast agent: correlation with cellular differentiation

The appearance of hepatocellular carcinoma (HCC) with contrast-enhanced ultrasound (CEUS) in the vascular phase is described and evaluated as to whether the enhancement pattern correlates with the degree of cellular differentiation. One hundred four HCCs were prospectively evaluated with CEUS using coherent-contrast imaging (CCI) and SonoVue with a low mechanical index (<0.2). The enhancement of HCCs in the vascular phase was analyzed according to the degree of pathological differentiation obtained by fine-needle biopsy. In the arterial phase, all HCCs except for four well differentiated ones (96.2%) showed enhancement (P<0.05). Histological differentiation of hypoechoic lesions in the early portal phase (7 HCCs; 16%) significantly differed from hyperechoic (1 HCC; 1%) or isoechoic lesions (87 HCCs; 83.6%) (P<0.05), with a significant probability of a worse differentiation in hypoechoic lesions. Histological differentiation of isoechoic lesions in the late phase (30 HCCs; 28.8%) significantly differed from hypoechoic lesions (74 HCCs; 71.2%) (P<0.05), with a significant probability of a better differentiation in isoechoic lesions. CEUS using CCI and SonoVue revealed enhancement in the arterial phase in >95% of HCCs, with a few well-differentiated cases not being diagnosed due to the absence of enhancement. Echogenicity in the portal and late phases correlated with cellular differentiation.     

Value of ultrasound in diagnosis of pneumothorax: a prospective study

Transthoracic ultrasound (US) is useful in the evaluation of a wide range of peripheral parenchymal, pleural, and chest wall diseases. Furthermore, it is increasingly used to guide interventional procedures of the chest and pleural space. The role of chest US in the diagnosis of pneumothorax has been established, but comparison with lung computed tomography (CT) scanning has not yet been completely performed. The purpose of this study is to prospectively compare the accuracy of US with that of chest radiography in the detection of pneumothorax, with CT as the reference standard. One hundred ninety-seven patients who were evaluated by spiral chest CT scan for various clinical indications were prospectively evaluated. Ultrasonography was performed by a radiologist, blinded to the chest CT findings. Sensitivity, specificity, and accuracy of ultrasound in the detection of pneumothorax were then compared with chest CT scan. CT scan showed pneumothorax in 92 patients. Sonography and plain X-ray of the chest revealed 74 and 56 cases of pneumothorax, respectively. Statistical analysis disclosed the US to be 80.4 % sensitive and 89 % specific in the detection of pneumothorax with an overall accuracy of 85 %. In this study, US was more sensitive than chest radiography in the detection of pneumothorax. The results of this study suggest that thoracic US, when performed by trained individuals, can be helpful for the detection of pneumothorax.     

The Usefulness of Pulsatile Flow Detection in Measuring Resistive Index in Renal Doppler US

Objective

To assess the usefulness of pulsatile flow detection (PFD), a newly developed function of color Doppler US, in measuring resistive index (RI) in renal Doppler US and to compare it with conventional color Doppler (CCD).

Materials and Methods

Fifty-six kidneys in 31 patients were randomly selected and divided into two groups. In group A, RI was measured first with the aid of CCD, and then with PFD. In group B, data were obtained in the reverse order. The time required for each RI measurement was recorded in seconds. The quality of the Doppler spectral waveform was subjectively graded as 0, 1, or 2 and examination time and waveform quality were compared between PFD and CCD.

Results

The time required to measure RI with PFD (PFD time) was less than with CCD (CCD time) (mean 42.7 secs vs. mean 70.3 secs; p = 0.031). There was no significant difference in PFD time between group A and B, but CCD time was shorter in group B (70.3 secs vs. 24.6 secs; p = 0.0004). Spectral waveform quality was not significantly different between PFD and CCD.

Conclusion

The time required to measure RI in kidneys can be shortened with the aid of the PFD function in color Doppler US without affecting the quality of the examination.     

Mesenteric whirlpool sign detected at color doppler ultrasound: Diagnostic value in adults

The purpose of this study was to evaluate the diagnostic value of the whirlpool sign detected at color Doppler sonography in adults complaining of acute abdominal pain. During a 2-year period, the whirlpool sign was systematically looked for with color Doppler sonography in all patients admitted in the emergency room for acute abdominal pain. The whirlpool sign was observed in 13 patients: 2 cases of surgically proven primary volvulus of the small bowel, 10 cases of proven or suspected small bowel obstruction secondary to adhesions, and 1 case of acute leukemia with enlarged mesenteric lymph nodes. In the first 12 cases, the whirlpool sign was associated with radiologic (N=9) and sonographic (N=12) signs of small bowel obstruction. In the last case, no sign of obstruction was observed. In patients who had the whirlpool sign and who underwent operations (N=6), primary or secondary volvulus was present in 3 cases but was absent in the other 3 cases. The whirlpool configuration detected with color Doppler sonography has to be considered as a sign of limited value, because it may be observed in various conditions, including primary or secondary volvulus, postsurgical adhesions without volvulus, and acute abdominal diseases without obstruction.     

Sonography of the postoperative brain: a report on 2 years of experience

Summary Thirty-seven patients were examined by post-operative high resolution real-time ultrasound over a period of 2 years. Useful data were obtained in all cases but the quality of information obtained was directly related to the size of the cranial window. In each patient, the first sonogram was performed during the 10th to 12th postoperative day to assess ventricular size and midline shift and any fluid collections present. This initial sonogram then served as a baseline study for further follow-up. Subsequent sonograms provided different information about tumor response to chemotherapy and/or irradiation, information not readily obtained by computed tomography.