Color Doppler ultrasound pulsatile flow signals of thoracic lesions: comparison of lung cancers and benign lesions

Lung ultrasound in a nutshell. Lines, signs, some applications, and misconceptions from a radiologist's point of view. Part 2

In recent years, lung ultrasound (LUS) has developed rapidly, and it is gaining growing popularity in various scenarios. There are constant attempts to introduce it to new fields. In addition, knowledge regarding lung and LUS has been augmented by the recent COVID-19 pandemics. In the first part of this review we discuss lines, signs and pheno-mena, profiles, some applications, and misconceptions. An aim of the second part of the review is mainly to discuss some advanced applications of LUS, including lung elastography, lung spectroscopy, colour and spectral Doppler, contrast-enhanced ultrasound of lung, speckled tracking of pleura, quantification of pulmonary oedema, predicting success of talc pleurodesis, asthma exacerbations, detecting chest wall invasion by tumours, lung biopsy, estimating pleural effusion volume, and predicting mechanical ventilatory weaning outcome. For this purpose, we reviewed literature concerning LUS.

WFUMB Technological Review: How to Perform Contrast-Enhanced Ultrasound of the Lung

The use of ultrasound has revolutionized the evaluation of pulmonary complaints and pathology. Historically, most lung ultrasound uses described are limited to B-mode, M-mode and occasionally color Doppler. However, the use of contrast can significantly expand the diagnostic capabilities of lung ultrasound. Ultrasound contrast enables significant expansion of therapeutic and intervention capabilities. We provide a detailed description of contrast administration, phases and uses in lung ultrasound. Additionally provided are example contrast use cases and illustrative examples of contrast use in a wide range of lung ultrasound applications including pneumonia, atelectasis, pulmonary embolism and neoplasms. Clinical practice examples will help providers incorporate contrast use into their lung ultrasound practice.

Contrast-enhanced ultrasonography characteristics of intrathoracic mass lesions in 36 dogs and 24 cats

Contrast‐enhanced ultrasonography (CEUS) is increasingly available for veterinary patients, however limited studies describe the use of this method for characterizing intrathoracic mass lesions. The aim of this prospective, observational study was to describe CEUS enhancement patterns for intrathoracic mass lesions in a sample of cats and dogs. Sixty patients (36 dogs, 24 cats) were included. Standardized CEUS examinations were performed for 41 pulmonary masses (68%) and 19 mediastinal masses (32%). Final diagnosis was based on cytology and/or histopathology. Absolute time to enhancement (TTE) values were recorded for the intrathoracic mass lesions and spleen. The spleen was used as a reference parenchymal organ to calculate relative TTE (rTTE) values. Absolute TTE of the spleen and intrathoracic mass lesions differed for dogs and cats (P = 0.001). The rTTE values significantly differed between lesions of neoplastic versus non‐neoplastic origin (P = 0.004). The majority of neoplastic pulmonary masses were supplied by bronchial arteries (63%), while most nonneoplastic pulmonary masses were supplied by pulmonary arteries (78%). The sensitivity and specificity for detecting pulmonary neoplastic masses with rTTE were 63% and 78%, respectively. Enhancement patterns for mediastinal thymomas and lymphomas significantly differed (P = 0.002). Thymomas enhanced heterogeneously in a centripetal pattern (86%), whereas lymphomas typically enhanced uniformly in a centrifugal pattern (75%). Findings indicated that CEUS is a feasible method for characterizing intrathoracic mass lesions in dogs and cats, however, the diagnostic sensitivity for detecting neoplastic pulmonary masses was low.

The Diagnostic Role of Ultrasound in the Chest

Although the plain radiograph and computed tomography remain undoubtedly the primary imaging modalities in the investigation of chest pathology, ultrasound can play an important complementary role, both in the diagnostic workup of a patient and in their subsequent management. Its lack of ionizing radiation, bedside availability and dynamic imaging capacity afford ultrasound certain advantages over other techniques; particularly in the critical care setting where conventional radiography is often suboptimal. This article reviews the technique and diagnostic application of ultrasound in the assessment of pathologies of the diaphragm, pleura, lung, mediastinum and chest wall.

Role of Arrival Time Difference Between Lesions and Lung Tissue on Contrast-Enhanced Sonography in the Differential Diagnosis of Subpleural Pulmonary Lesions

OBJECTIVES

The purpose of this study was to explore the diagnostic value of the arrival time difference between lesions and surrounding lung tissue on contrast-enhanced sonography of subpleural pulmonary lesions.

METHODS

A total of 110 patients with subpleural pulmonary lesions who underwent both conventional and contrast-enhanced sonography and had a definite diagnosis were enrolled. After contrast agent injection, the arrival times in the lesion, lung, and chest wall were recorded. The arrival time differences between various tissues were also calculated.

RESULTS

Statistical analysis showed a significant difference in the lesion arrival time, the arrival time difference between the lesion and lung, and the arrival time difference between the chest wall and lesion (all P < .001) for benign and malignant lesions. Receiver operating characteristic curve analysis revealed that the optimal diagnostic criterion was the arrival time difference between the lesion and lung, and that the best cutoff point was 2.5 seconds (later arrival signified malignancy). This new diagnostic criterion showed superior diagnostic accuracy (97.1%) compared to conventional diagnostic criteria.

CONCLUSIONS

The individualized diagnostic method based on an arrival time comparison using contrast-enhanced sonography had high diagnostic accuracy (97.1%) with good feasibility and could provide useful diagnostic information for subpleural pulmonary lesions.

Ultrasound of the pleurae and lungs

The value of ultrasound techniques in examination of the pleurae and lungs has been underestimated over recent decades. One explanation for this is the assumption that the ventilated lungs and the bones of the rib cage constitute impermeable obstacles to ultrasound. However, a variety of pathologies of the chest wall, pleurae and lungs result in altered tissue composition, providing substantially increased access and visibility for ultrasound examination. It is a great benefit that the pleurae and lungs can be non-invasively imaged repeatedly without discomfort or radiation exposure for the patient. Ultrasound is thus particularly valuable in follow-up of disease, differential diagnosis and detection of complications. Diagnostic and therapeutic interventions in patients with pathologic pleural and pulmonary findings can tolerably be performed under real-time ultrasound guidance. In this article, an updated overview is given presenting not only the benefits and indications, but also the limitations of pleural and pulmonary ultrasound.

Diagnostic impact of color Doppler ultrasound-guided core biopsy on fine-needle aspiration of anterior mediastinal masses

Although lymphoma and thymoma are common etiologies of anterior mediastinal masses (AMMs), smaller percentages and numbers of patients with these diseases have been enrolled in previous ultrasound-guided biopsy studies. To date, there has been no study of color Doppler sonographic features to support the differentiation of AMMs. For this retrospective cohort study, a search of the database of the China Medical University Hospital using the clinical coding "ultrasound-guided biopsy" was conducted for the period December 2003 to February 2013. We selected patients diagnosed with AMMs (not cysts) using radiographic records. This search yielded a list of 80 cases. Real-time ultrasound-guided core needle biopsy (CNB) was performed in all but 5 patients without a sufficient safety range. In 89% (67/75) of these ultrasound-guided CNB cases, the diagnostic accuracy achieved subclassification. Fine-needle aspiration cytology achieved subclassification in only 10% of cases. On color Doppler sonography, 71% of lymphomas were characterized as "rich vascular with central/crisscross collocations" and 29% as "avascular or localized/scattered peripheral vessels." However, decreased proportions of "rich vascular with central/crisscross collocations" were found in lung cancer (4% [1/23], odds ratio = 0.018, 95% confidence interval: 0.002-0.154, p < 0.001) and thymoma/thymic carcinoma (25% [4/16]; odds ratio = 0.133, 95% confidence interval: 0.035-0.514, p = 0.003) compared with the lymphoma group. We conclude that the vessels in lymphoma AMMs have specific patterns on color Doppler sonography. Ultrasound-guided CNB of AMMs had an accuracy of ≤ 89% in diagnosis and subclassification. Fine-needle aspiration cytology itself cannot aid in the diagnosis. Color Doppler sonographic evaluation of AMMs followed by real-time CNB is a more efficient method.

Comparative study evaluating the role of color Doppler sonography and computed tomography in predicting chest wall invasion by lung tumors

OBJECTIVES

To analyze qualitative and quantitative parameters of lung tumors by color Doppler sonography, determine the role of color Doppler sonography in predicting chest wall invasion by lung tumors using spectral waveform analysis, and compare color Doppler sonography and computed tomography (CT) for predicting chest wall invasion by lung tumors.

METHODS

Between March and September 2007, 55 patients with pleuropulmonary lesions on chest radiography were assessed by grayscale and color Doppler sonography for chest wall invasion. Four patients were excluded from the study because of poor acoustic windows. Quantitative and qualitative sonographic examinations of the lesions were performed using grayscale and color Doppler imaging. The correlation between the color Doppler and CT findings was determined, and the final outcomes were correlated with the histopathologic findings.

RESULTS

Of a total of 51 lesions, 32 were malignant. Vascularity was present on color Doppler sonography in 28 lesions, and chest wall invasion was documented in 22 cases. Computed tomography was performed in 24 of 28 evaluable malignant lesions, and the findings were correlated with the color Doppler findings for chest wall invasion. Of the 24 patients who underwent CT, 19 showed chest wall invasion. The correlation between the color Doppler and CT findings revealed that color Doppler sonography had sensitivity of 95.6% and specificity of 100% for assessing chest wall invasion, whereas CT had sensitivity of 85.7% and specificity of 66.7%.

CONCLUSIONS

Combined qualitative and quantitative color Doppler sonography can predict chest wall invasion by lung tumors with better sensitivity and specificity than CT. Although surgery is the reference standard, color Doppler sonography is a readily available, affordable, and noninvasive in vivo diagnostic imaging modality that is complementary to CT and magnetic resonance imaging for lung cancer staging.

Thoracic ultrasound demonstrates variable location of the intercostal artery

BACKGROUND

Ultrasound (US) guidance is advocated to reduce complications from thoracocentesis or intercostal catheter (ICC) insertion. Although imaging of the intercostal artery (ICA) with Doppler US has been reported, current thoracic guidelines do not advocate this, and bleeding from a lacerated ICA continues to be a rare but serious complication of thoracocentesis or ICC insertion.

OBJECTIVES

It was the aim of this study to describe a method to visualise the ICA at routine US-guided thoracocentesis and map its course across the posterior chest wall.

METHOD

The ICA was imaged in 22 patients undergoing US-guided thoracocentesis, at 4 positions across the back to the axilla. Its location, relative to the overlying rib, was calculated as the fraction of the intercostal space (ICS) below the inferior border of that rib.

RESULTS

An ICA was identified in 74 of 88 positions examined. The ICA migrated from a central 'vulnerable' location within the ICS near the spine (0.28, range 0.21-0.38; p < 0.001) towards the overlying rib (0.08, range 0.05-0.11; p < 0.001) in the axilla.

CONCLUSIONS

The ICA can be visualised with US and is more exposed centrally within the ICS in more posterior positions; however, there is a marked variation between individuals, such that the ICA may lie exposed in the ICS even as far lateral as the axilla. Future studies need to identify which patients are at risk for a 'low-lying' ICA to further define the role of US imaging of the ICA during thoracocentesis or ICC insertion.

A novel Doppler spectral index for differentiating benign from malignant lung tumors

PURPOSE

It has been reported that the resistance index (RI) and pulsatility index (PI) are of limited value in differentiating lung cancers from benign lesions. We hypothesized that a vascular work index (VWI), derived from Doppler spectral waveforms, would yield better results.

METHODS

Forty-one patients were enrolled, 20 of them having malignancies and 21 having benign lesions. The VWI was defined as the square of peak systolic velocity times the time-velocity integral. Maximal VWI, minimal RI, and minimal PI of each tumor were used for analysis.

RESULTS

Significantly higher VWI values were found in malignant tumors compared with benign lesions (p < 0.0001). VWI was shown by analysis of the receiver operating characteristic curve to be a best predictor of lung malignancies than PI and RI (p < 0.05), with a 0.89 (95% confidence interval, 0.80-0.98) area under the receiver operating characteristic curve.

CONCLUSIONS

VWI may be a useful index to help differentiate malignant from benign lung tumors.

Contrast enhanced ultrasonography (CEUS) in peripheral lung lesions: A study of 60 cases

INTRODUCTION

The authors report their experience in 60 patients with infectious and neoplastic peripheral pulmonary lesions studied by conventional radiology, B-Mode ultrasound (US) and computed tomography (CT). In view of the particular pulmonary vascularization (consisting of both pulmonary and bronchial arteries) the patients underwent also contrast enhanced ultrasound (CEUS) using a II-generation contrast agent, SonoVue (sulphur hexafluoride microbubbles surrounded by a phospholipid shell).

METHODS AND RESULTS

In this study, the sensitivity of CEUS reached 95% in the characterization of peripheral pulmonary lesions, which is similar to the sensitivity of CT (97%). The method used in this case-study was free of significant side effects.

DISCUSSION

This preliminary clinical experience seems to confirm the possibility of using SonoVue enhanced US to make a differential diagnosis between infectious and neoplastic lesions based on a qualitative and quantitative assessment, by evaluating the enhancement pattern (homogeneous or inhomogeneous), arrival time of the contrast agent in the lesion, the possibility to identify the pulmonary arteries and time of contrast agent elimination.

Dynamic flow US, color Doppler US, and power Doppler US in the assessment of vessel signals of thoracic lesions abutting pulsatile organs

RATIONALE AND OBJECTIVES

Dynamic flow ultrasound (DFUS) is a new color Doppler imaging method with better B-mode imaging and fewer blooming effects and color noises. This study was designed to compare the imaging quality of vessel signals in thoracic lesions using DFUS, color Doppler US (CDUS), and power Doppler US (PDUS).

MATERIALS AND METHODS

Thirty-four patients with thoracic lesions abutting pulsatile organs [heart (n = 13), aorta (n = 14) and pulmonary artery (n = 7)] and undergoing complete chest US examinations were included to assess the imaging quality about vessel signals, blooming effect, color noise, and the influence of decision in needle biopsy between different US modes.

RESULTS

Our results showed that DFUS, CDUS, and PDUS could all demonstrate the vessel signals clearly (all P > .05). However, when focusing on the blooming effect and color noise, DFUS showed the more superior imaging quality than CDUS and PDUS (all P < or = .001); and acceptable blooming effects/color noise were found with 100% (34/34)/97% (33/34), 35% (12/34)/68% (23/34), and 26% (9/34)/38% (13/34) in DFUS, CDUS, and PDUS, respectively. Especially, in the assessment of decision making for percutaneous needle biopsy, DFUS had the less influence than CDUS and PDUS (3% [1/33] versus 29% [10/34] and 3% [1/33] versus 38% [13/34], both P < .01).

CONCLUSIONS

We concluded that DFUS has a clearly more superior imaging quality than CDUS and PDUS in demonstrating the vessel signals of thoracic lesions, with less blooming effect and color noise.

Color Doppler US pulmonary artery vessel signal: a sign for predicting the benign lesions

The lung cancer blood supply originates from the bronchial artery. If vessel signals within pulmonary lesions can be confirmed to be those of the pulmonary artery, color Doppler ultrasound (US) should be able to predict and differentiate benign lesions from lung cancers. Two hundred sixty-four patients with abutting thoracic lesions (including 125 lung cancers and 139 benign lesions) underwent color Doppler US examinations. A pulsatile flow, with the vessel signal length on sonographic appearance > or =1 cm demonstrated by color Doppler US, was arbitrarily defined as a pulmonary artery vessel signal. Of the 264 thoracic lesions, 73 (58%) lung cancers and 107 (77%) benign lesions had detectable color Doppler US pulsatile flow vessel signals. Analyzing the pulsatile flow vessel signals, the color Doppler US pulmonary artery vessel signal was present in 74 (53%) benign lesions, but was found in only two (2%) lung cancers of a specific alveolar cell carcinoma with lobar consolidation. Using the pulmonary artery vessel signal, color Doppler US can be valuable in predicting and differentiating benign lesions from lung cancers (p < 0.0001, sensitivity = 0.53, specificity = 0.98 and positive likelihood ratio 26.5). In conclusion, color Doppler US pulmonary artery vessel signal sign is useful in predicting and differentiating benign lesions from lung cancers.

Contrast-enhanced sonography for differential diagnosis of pleurisy and focal pleural lesions of unknown cause

BACKGROUND

Ultrasound enables the visualization of pleural-based lesions with a poor correlation to specific pathology. At this time, there are no data about the diagnostic value of contrast-enhanced sonography (CES) in pleural lesions.

METHODS

From August 2004 to January 2005, 25 consecutive patients with clinical symptoms of pleurisy and focal pleural lesions of unknown origin seen on B-mode ultrasonography were prospectively studied by CES. The lesions were diagnosed as pleuropneumonia (n = 12), pulmonary embolism/infarction (n = 7), malignant lymphoma (n = 2), pleural metastasis (n = 2), granuloma (n = 1), and unknown cause (n = 1). The diagnosis of the lesions was confirmed by contrast-enhanced CT scanning (n = 20), scintigraphy (n = 3), and follow-up (n = 2). Time to the enhancement of the contrast agent was determined. The CES patterns were evaluated during the arterial phase (ie, 2 to 30 s) and the parenchymal phase (ie, 1 to 5 min). The extent of the enhancement of pleural lesions was classified using normal liver tissue as an in vivo reference (absent, hypoechoic, isoechoic, hyperrechoic, or mixed echogenicity).

RESULTS

In 20 patients, an enhancement of the pleural lesion was seen. All 12 patients with pleuropneumonia had a short time to enhancement (between 1 and 6 s), and a marked enhancement (isoechoic/hyperechoic) during the arterial and parenchymal phase. In the remaining 13 patients with other diagnoses than pleuropneumonia, 5 patients had no enhancement and 8 patients had a delayed time to enhancement (> 6 s). The extent of the enhancement was reduced (hypoechoic/anechoic) in 12 of 13 patients during the arterial and parenchymal phases.

CONCLUSION

In patients with pleurisy and pleural lesions of unknown cause that were found sonographically, CES enables the diagnosis or exclusion of pleuropneumonia.

Colour Doppler ultrasound mapping of chest wall lesions

Spectral curve-analysis of arterial flow signals (FS) in patients with pulmonary lesions is able to discriminate FS of bronchial arteries (BA) from FS of pulmonary arteries (PA). In patients with chest wall lesions a different FS from that of the BA/PA can be obtained. The aim of the study was to evaluate and characterize arterial supply of chest wall lesions using quantitative colour Doppler ultrasound (CDS). Between September 2002 and June 2003, 29 consecutive patients with chest wall lesions were examined by CDS. 16 lesions were located strictly to the chest wall (group I). 13 lesions had a chest wall lesion with pulmonary extension (group II). The following parameters were prospectively determined: (1) qualitative CDS (absence or evidence of vascularity); (2) quantitative CDS of intercostal or non-intercostal located arterial FS (resistive index (RI) and pulsatility index (PI)); (3) number of different arterial FS in one lesion using CDS-mapping. In a control group of 17 healthy volunteers quantitative measurement of RI and PI of the intercostal artery (ICA) was performed. 4 of 29 patients (14%) had no FS by CDS mapping. Quantitative CDS parameters of the control group were mean RI of ICA 0.88 (+/-0.056); mean PI of ICA 2.88 (+/-0.643); of group I mean RI of ICA 0.79 (+/-0.127) mean PI of ICA 1.93 (+/-0.641), and of group II mean RI of ICA 0.79 (+/-0.144), mean PI of ICA 2.1 (+/-1.015), mean RI of non-ICA 0.68 (+/-0.675) mean PI of non-ICA 2.5 (+/-2.506). Median RI as well as PI-value obtained within the chest wall (ICA) do not differ between group I, group II, and the control group. Within group II impedance measurements discriminates intercostal from non-intercostal arterial supply. In 29 patients 37 different arterial FS were obtained. None of the 16 patients in group I and 8 of the 13 patients in group II had 2 or more different FS. Lesions strictly located to the chest wall had an arterial supply characteristic for ICA by quantitative CDS. Chest wall lesions with pulmonary extension demonstrate a complex arterial supply by quantitative CDS.

Estimation of inflammation by Doppler ultrasound: quantitative changes after intra-articular treatment in rheumatoid arthritis

OBJECTIVE

To evaluate the use of ultrasound, including quantitative Doppler analysis of synovial vascularisation, before and after intra-articular treatment with glucocorticosteroids in patients with rheumatoid arthritis (RA).

METHODS

51 patients with RA were followed prospectively after an intra-articular glucocorticosteroid injection. Disease modifying antirheumatic drug treatment was kept unchanged and no further injections given in this observation period. At baseline, disease activity was estimated clinically by target join pain on a 100 mm visual analogue scale, on which the target joint was scored 0-3 for swelling and tenderness, and by ultrasound measurements of grey scale pixels, colour Doppler pixels, and the spectral Doppler resistive index (RI) as indicators of synovial swelling and inflammation. After four weeks, the measurements were repeated on the same joint. An observer unaware of the sequence and patient number evaluated the ultrasound images.

RESULTS

At one month follow up after the glucocorticosteroid injection, a marked decrease in the fraction of colour pixels was seen in 41/51 patients (Student's t test p<0.001). Correspondingly, the RI increased indicating a diminished flow to the synovium (Student's t test p<0.01). Both the fraction of colour pixels and the RI values corresponded with the clinical evaluation and with the subjective effect of the treatment. The synovial membrane volume estimated by total amount of pixels showed a significant decrease by 31% after treatment.

CONCLUSION

Ultrasound-Doppler seems to be a promising tool for the estimation of synovial activity in arthritis. After intra-articular glucocorticosteroid, changes in RI and fraction of colour pixels may both be used as quantitative measurements of the blood flow.

Spectral Doppler and resistive index. A promising tool in ultrasonographic evaluation of inflammation in rheumatoid arthritis

PURPOSE

To evaluate the use of spectral Doppler in the longitudinal follow-up of inflammatory joint involvement in rheumatoid arthritis (RA) by comparing resistive index (RI) findings with color fraction and pain on a visual analog scale (VAS).

MATERIAL AND METHODS

Five patients on unchanged disease modifying anti-rheumatic drugs (DMARD) treatment were followed after an intra-articular corticosteroids injection and received no further injections in the observation period. They were followed clinically and by ultrasound using color Doppler pixels and the spectral Doppler RI as indicators of inflammation. At 1, 6 and 12 months the measurements were repeated on the same joint.

RESULTS

At 1-month follow-up after the corticosteroids injection, a marked decrease in the color fraction was seen in 4 out of 5 patients, while the fifth patient had a moderate decrease (Wilcoxon p < 0.05). The changes in RI showed correspondingly a marked increase in 4 out of 5 patients indicating a diminished flow to the synovium (Wilcoxon p < 0.05). The effect of the corticosteroid injection could still be seen after 1 year in 4 out of 5 patients. In RI, pixel fraction and VAS there was improvement compared with the baseline values; however, only the pixel fraction was statistically significant (Wilcoxon p < 0.05).

CONCLUSION

RI seems to be an objective alternative to pixel estimation of the degree of inflammation and treatment response in RA.

Color Doppler sonographic mapping of pulmonary lesions: evidence of dual arterial supply by spectral analysis

OBJECTIVE

Within pulmonary lesions, flow signals of pulmonary arteries can be discriminated from flow signals of central bronchial and peripheral bronchial arteries on color Doppler sonography. Our aim was to evaluate the evidence and frequency of different arterial supplies of pleural-based pulmonary lesions using qualitative and quantitative color Doppler sonography.

METHODS

Forty-one patients with roentgenologically confirmed pleural-based pulmonary lesions were investigated by color Doppler sonography. The following parameters were investigated: (1) qualitative color Doppler sonographic evidence of vascularization, (2) quantitative color Doppler sonographic evidence of arterial flow signals (resistive index and pulsatility index), and (3) number of different arterial flow signals in 1 lesion by color Doppler sonographic mapping.

RESULTS

We found no vascularization in 5 patients, sparse vascularization in 21, and pronounced vascularization in 15. Quantitative color Doppler sonographic parameters were as follows: mean pulmonary artery resistive index, 1.2; mean central bronchial artery resistive index, 0.5; mean peripheral bronchial artery resistive index, 0.7; mean pulmonary artery pulsatility index, 7.8; mean central bronchial artery pulsatility index, 0.7; and mean peripheral bronchial artery pulsatility index, 1.6. There was a significant difference between all types of flow signals for resistive and pulsatility index values but not between pulmonary and peripheral bronchial arteries (P = .068). In 41 patients, 57 different arterial flow signals were determined; 19 (46%) of these patients had 2 or more different arterial flow signals in a lesion. There was no significant difference between benign and malignant lesions regarding the number of flow signals.

CONCLUSIONS

Evidence of at least a dual arterial supply can be found on quantitative color Doppler sonography in almost 50% of pulmonary lesions. A single spectral analysis is not suitable for characterization of the arterial supply of pulmonary lesions.

Real-time chest ultrasonography: a comprehensive review for the pulmonologist

This review discusses real-time pulmonary ultrasonography (US) for the practicing pulmonologist. US supplements chest radiography and chest CT scanning. Major advantages include bedside availability, absence of radiation, and guided aspiration of fluid-filled areas and solid tumors. Pulmonary vessels and vascular supply of consolidations may be visualized without contrast. US may help to diagnose conditions such as pneumothorax, hemothorax, pleural or pericardial effusion, pneumonia, and pulmonary embolism in the critically ill patient who is in need of bedside diagnostic testing. The technique of US, which is cost-effective compared to CT scanning and MRI, may be learned relatively easily by the pulmonologist.

Bronchioloalveolar carcinoma: sonographic pattern of 'pneumonia'

BACKGROUND

the sonographic pattern of bacterial pneumonia is predominantly well known and characterized by an air bronchogram, a marked vascularity on color Doppler sonography, and a high-impedance arterial flow pattern on Doppler spectral analysis.

METHODS

in a retrospective study the sonographic findings in seven patients with peripheral BAC on X-ray examination were evaluated in relation to number, size, margins, echomorphology and sonographic arterial flow patterns of the lesions.

RESULTS

the following sonomorphologic characteristics were found: multiple foci (n=4), single foci (n=3), smooth margins (n=5), irregular margins (n=2) and maximal diameter of size (range 5-15 cm). The echomorphology of the lesions was homogenously hypoechoic (n=1) or showed airbronchograms (n=6). Color Doppler sonography revealed a vascular tree pattern (n=5) or a marked presence of blood vessels (n=2). Doppler flow spectral analysis of arteries in investigated patients (n=5) demonstrates a high impedance (triphasic) flow pattern in four patients and a low impedance (monophasic) flow pattern in one patient.

CONCLUSIONS

these findings indicate that BAC frequently shows a sonographic pattern of 'pneumonia'.

Transthoracic US of the chest: clinical uses and applications

Transthoracic ultrasound (US) of the chest 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 technique lends itself to bedside use in the intensive care unit, where suboptimal radiography may mask or mimic clinically significant abnormalities. The authors discuss the uses, techniques and applications of US of the chest. The sonographic appearances of pleural diseases (pleural effusion, pneumothorax, pleural mass, and mesothelioma), parenchymal diseases (pneumonia, neoplasms, heart failure, infarct, and rounded atelectasis), chest wall abnormalities (chest wall tumor and rib fracture), and diaphragmatic paralysis are discussed. The use of US in guiding biopsy, thoracocentesis, and other interventional procedures of the lung, pleural space, and mediastinum are also reviewed.

Alternative imaging of the lung

This article illustrates the roles of ultrasonography, scintigraphy, and computed tomography (CT) as alternative techniques for pulmonary imaging in small animals. The advantages and limitations of each modality, normal anatomic features, and technical considerations will be discussed. Selected applications will be examined and include pulmonary consolidation, neoplasia and other masses, atelectasis, pneumothorax, dystrophic mineralization, diffuse infiltrative disease, and pulmonary embolism. The use of ultrasound and CT-guided interventional procedures will also be briefly discussed.