AIUM practice guideline for the performance of an ultrasound examination of the abdomen and/or retroperitoneum

A 5G-based telerobotic ultrasound system provides qualified abdominal ultrasound services for patients on a rural island: a prospective and comparative study of 401 patients

PURPOSE

To explore the feasibility of a 5G-based telerobotic ultrasound (US) system for providing qualified abdominal US services on a rural island.

METHODS

This prospective study involved two medical centers (the tele-radiologist site's hospital and the patient site's hospital) separated by 72 km. Patients underwent 5G-based telerobotic US by tele-radiologists and conventional US by on-site radiologists from September 2020 to March 2021. The clinical feasibility and diagnostic performance of the 5G-based telerobotic abdominal US examination were assessed based on safety, duration, image quality, diagnostic findings, and questionnaires.

RESULTS

A total of 401 patients (217 women and 184 men; mean age, 54.96 ± 15.43 years) were enrolled. A total of 90.1% of patients indicated no discomfort with the telerobotic US examination. For the examination duration, telerobotic US took longer than conventional US (12.54 ± 3.20 min vs. 7.23 ± 2.10 min, p = 0.001). For image quality scores, the results of the two methods were similar (4.54 ± 0.63 vs. 4.57 ± 0.61, p = 0.112). No significant differences were found between the two methods in measurements for the aorta, portal vein, gallbladder, kidney (longitudinal diameter), prostate, and uterus; however, telerobotic US underestimated the transverse diameter of the kidney (p < 0.05). A total of 504 positive results, including 31 different diseases, were detected. Among them, 455 cases were identified by the two methods; 17 cases were identified by telerobotic US only; and 32 cases were identified by conventional US only. There was good consistency in the diagnosis of 29 types of disease between the two methods (κ = 0.773-1.000). Furthermore, more than 90% of patients accepted the telerobotic US examination and agreed to pay additional fees in future.

CONCLUSION

The 5G-based telerobotic US system can expand access to abdominal US services for patients in rural areas, thereby reducing health care disparities.

Professional Standards in Medical Ultrasound - EFSUMB Position Paper (Short Version) - General Aspects

This first position paper of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) on professional standards presents a common position across the different medical professions within EFSUMB regarding optimal standards for the performing and reporting of ultrasound examinations by any professional ultrasound operator. It describes general aspects of professionality that ensure procedure quality, effectiveness, efficiency, and sustainability in virtually all application fields of medical ultrasound. Recommendations are given related to safety and indication of ultrasound examinations, requirements for examination rooms, structured examination, systematic reporting of results, and management, communication and archiving of ultrasound data. The print version of this article is a short version. The long version is published online.

Professional Standards in Medical Ultrasound - EFSUMB Position Paper (Long Version) - General Aspects

This first position paper of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) on professional standards presents a common position across the different medical professions within EFSUMB regarding optimal standards for the performing and reporting of ultrasound examinations by any professional ultrasound operator. It describes general aspects of professionality that ensure procedure quality, effectiveness, efficiency, and sustainability in virtually all application fields of medical ultrasound. Recommendations are given related to safety and indication of ultrasound examinations, requirements for examination rooms, structured examination, systematic reporting of results, and management, communication and archiving of ultrasound data. The print version of this article is a short version. The long version is published online.

Very Low Frequency Radial Modulation for Deep Penetration Contrast-Enhanced Ultrasound Imaging

Contrast-enhanced ultrasound imaging allows vascular imaging in a variety of diseases. Radial modulation imaging is a contrast agent-specific imaging approach for improving microbubble detection at high imaging frequencies (≥7.5 MHz), with imaging depth limited to a few centimeters. To provide high-sensitivity contrast-enhanced ultrasound imaging at high penetration depths, a new radial modulation imaging strategy using a very low frequency (100 kHz) ultrasound modulation wave in combination with imaging pulses ≤5 MHz is proposed. Microbubbles driven at 100 kHz were imaged in 10 successive oscillation states by manipulating the pulse repetition frequency to unlock the frame rate from the number of oscillation states. Tissue background was suppressed using frequency domain radial modulation imaging (F-RMI) and singular value decomposition-based radial modulation imaging (S-RMI). One hundred-kilohertz modulation resulted in significantly higher microbubble signal magnitude (63-88 dB) at the modulation frequency relative to that without 100-kHz modulation (51-59 dB). F-RMI produced images with high contrast-to-tissue ratios (CTRs) of 15 to 22 dB in a stationary tissue phantom, while S-RMI further improved the CTR (19-26 dB). These CTR values were significantly higher than that of amplitude modulation pulse inversion images (11.9 dB). In the presence of tissue motion (1 and 10 mm/s), S-RMI produced high-contrast images with CTR up to 18 dB; however, F-RMI resulted in minimal contrast enhancement in the presence of tissue motion. Finally, in transcranial ultrasound imaging studies through a highly attenuating ex vivo cranial bone, CTR values with S-RMI were as high as 23 dB. The proposed technique demonstrates successful modulation of microbubble response at 100 kHz for the first time. The presented S-RMI low-frequency radial modulation imaging strategy represents the first demonstration of real-time (20 frames/s), high-penetration-depth radial modulation imaging for contrast-enhanced ultrasound imaging.

Development and evaluation of the focused assessment of sonographic pathologies in the intensive care unit (FASP-ICU) protocol

Background

The use of ultrasonography in the intensive care unit (ICU) is steadily increasing but is usually restricted to examinations of single organs or organ systems. In this study, we combine the ultrasound approaches the most relevant to ICU to design a whole-body ultrasound (WBU) protocol. Recommendations and training schemes for WBU are sparse and lack conclusive evidence. Our aim was therefore to define the range and prevalence of abnormalities detectable by WBU to develop a simple and fast bedside examination protocol, and to evaluate the value of routine surveillance WBU in ICU patients.

Methods

A protocol for focused assessments of sonographic abnormalities of the ocular, vascular, pulmonary, cardiac and abdominal systems was developed to evaluate 99 predefined sonographic entities on the day of admission and on days 3, 6, 10 and 15 of the ICU admission. The study was a clinical prospective single-center trial in 111 consecutive patients admitted to the surgical ICUs of a tertiary university hospital.

Results

A total of 3003 abnormalities demonstrable by sonography were detected in 1275 individual scans of organ systems and 4395 individual single-organ examinations. The rate of previously undetected abnormalities ranged from 6.4 ± 4.2 on the day of admission to 2.9 ± 1.8 on day 15. Based on the sonographic findings, intensive care therapy was altered following 45.1% of examinations. Mean examination time was 18.7 ± 3.2 min, or 1.6 invested minutes per detected abnormality.

Conclusions

Performing the WBU protocol led to therapy changes in 45.1% of the time. Detected sonographic abnormalities showed a high rate of change in the course of the serial assessments, underlining the value of routine ultrasound examinations in the ICU.

Trial registration The study was registered in the German Clinical Trials Register (DRKS, 7 April 2017; retrospectively registered) under the identifier DRKS00010428.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03811-2.

Ultrasonographic predictors in chronic kidney disease: A hospital based case control study

BACKGROUND

Prevalence of Chronic Kidney Disease (CKD) is increasing globally with the concomitant upsurge in diabetes mellitus and hypertension. We explored the research question whether Ultrasonographic (US) renal parameters are potential predictors of CKD?

MATERIALS AND METHODS

A case control study was conducted at a tertiary care hospital that included 50 confirmed cases of CKD and 100 nondiseased controls. Renal length, renal parenchymal thickness, and renal cortical thickness were measured in both cases and controls by ultrasound examination. Corticomedullary differentiation and renal cortical echogenicity were also assessed.

RESULTS

US parameters of renal length, renal parenchymal thickness, and renal cortical thickness were found to be significantly and strongly associated with the presence of CKD. The strongest association was observed with renal cortical echogenicity (OR 27.33, 95% CI 8.82-84.63). The association of reduced renal cortical thickness (OR 6.14, 95% CI 1.59-23.62), and renal length (OR 2.72, 95% CI 1.13-8.26) were independent and significant predictors of presence of CKD.

CONCLUSIONS

Specific US parameters of renal cortical echogenicity, cortical thickness, and length of kidney have a strong potential for independently establishing the diagnosis and evaluation of progression of CKD.

Testing telediagnostic right upper quadrant abdominal ultrasound in Peru: A new horizon in expanding access to imaging in rural and underserved areas

Background

Hepatic and biliary diseases are prevalent worldwide, but the majority of people lack access to diagnostic medical imaging for their assessment. The liver and gallbladder are readily amenable to sonographic examination, and ultrasound is a portable, cost-effective imaging modality suitable for use in rural and underserved areas. However, the deployment of ultrasound in these settings is limited by the lack of experienced sonographers to perform the exam. In this study, we tested an asynchronous telediagnostic system for right upper quadrant abdominal ultrasound examination operated by individuals without prior ultrasound experience to facilitate deployment of ultrasound to rural and underserved areas.

Methods

The teleultrasound system utilized in this study employs volume sweep imaging and a telemedicine app installed on a tablet which connects to an ultrasound machine. Volume sweep imaging is an ultrasound technique in which an individual scans the target region utilizing preset ultrasound sweeps demarcated by easily recognized external body landmarks. The sweeps are saved as video clips for later interpretation by an experienced radiologist. Teleultrasound scans from a Peruvian clinic obtained by individuals without prior ultrasound experience were sent to the United States for remote interpretation and quality assessment. Standard of care comparison was made to a same-day ultrasound examination performed by a radiologist.

Results

Individuals without prior ultrasound experience scanned 144 subjects. Image quality was rated “poor” on 36.8% of exams, “acceptable” on 38.9% of exams, and “excellent” on 24.3% of exams. Among telemedicine exams of “acceptable” or “excellent” image quality (n = 91), greater than 80% of the liver and gallbladder were visualized in the majority of cases. In this group, there was 95% agreement between standard of care and teleultrasound on whether an exam was normal or abnormal, with a Cohen’s kappa of 0.84 (95% CI 0.7–0.98, p <0.0001). Finally, among these teleultrasound exams of “acceptable” or “excellent” image quality, the sensitivity for cholelithiasis was 93% (95% CI 68.1%-99.8%), and the specificity was 97% (95% CI 89.5%-99.6%).

Conclusion

This asynchronous telediagnostic system allows individuals without prior ultrasound experience to effectively scan the liver, gallbladder, and right kidney with a high degree of agreement with standard of care ultrasound. This system can be deployed to improve access to diagnostic imaging in low-resource areas.

Versatile Low-Cost Volumetric 3-D Ultrasound Platform for Existing Clinical 2-D Systems

Ultrasound imaging has indications across many areas of medicine, but the need for training and the variability in skill and acquired image quality among 2-D ultrasound users have limited its wider adoption and utilization. Low-cost volumetric ultrasound with a known frame of reference has the potential to lower these operator-dependent barriers and enhance the clinical utility of ultrasound imaging. In this paper, we improve upon our previous research-scanner-based prototype to implement a versatile volumetric imaging platform for existing clinical 2-D ultrasound systems. We present improved data acquisition and image reconstruction schemes to increase quality, streamline workflow, and provide real-time visual feedback. We present initial results using the platform on a Vimedix simulator, as well as on phantom and in vivo targets using a variety of clinical ultrasound systems and probes.

Extrabiliary Pathology Identified by Right Upper Quadrant Abdominal Ultrasound in Emergency Department Patients

BACKGROUND

The effectiveness of point of care (POC) right upper quadrant ultrasound (RUQ US) in the diagnosis of biliary disease has been well studied. Extrabiliary pathology that might remain undetected in the course of typical, focused POC RUQ US has not been directly examined.

OBJECTIVES

Our objective was to determine the prevalence and clinical significance of extrabiliary findings (EBFs) seen on radiology-performed, comprehensive RUQ US.

METHODS

We conducted a retrospective review of all adult patients undergoing radiology-performed RUQ US in the emergency department (ED) between January 2007 and April 2012. Ultrasound findings and contemporaneous laboratory values were collected. EBFs were identified and further classified by clinical significance.

RESULTS

A total of 1579 charts were included, demonstrating a total of 1030 EBFs, with 747 (47.3% [95% confidence interval {CI}, 44.8-49.8%]) patients demonstrating ≥ 1 EBF. Of these EBFs, 184 were classified as clinically significant (CSEBFs) and 150 (9.5% [95% CI, 8.1-11.0%]) patients had ≥ 1 CSEBF. A total of 50 unspecified masses were seen in 47 (3.0% [95% CI, 2.1-3.8%]) patients, with 8 (0.5%) representing a previously undiagnosed malignancy.

CONCLUSION

CSEBFs were seen in < 10% of ED patients undergoing comprehensive RUQ US. Nonspecific masses were seen in 3% of patients, but < 1% of patients were found to have a new malignancy.

Using Standardized Patients to Teach Point-of-Care Ultrasound-Guided Physical Examination Skills to Internal Medicine Residents

BACKGROUND

Point-of-care (POC) ultrasound has been shown to improve procedural outcomes and physical examination accuracy in multiple settings. There are limited data regarding the optimal way to train nonradiologists in POC ultrasound. This is a primary barrier to more widespread use of ultrasound in the physical examination.

OBJECTIVE

We created a workshop to instruct postgraduate year (PGY)-2 and PGY-3 internal medicine residents in POC ultrasound imaging of the abdominal aorta and kidneys.

METHODS

A half-day simulation center workshop was created to review ultrasound operations and teach residents to independently obtain ultrasound images of the abdominal aorta and kidneys on standardized patients with normal anatomy. The workshop incorporated didactic instruction and hands-on ultrasound practice in small groups. Each resident's ability to independently obtain ultrasound images was assessed using a preworkshop and postworkshop skills examination with a standardized patient. Resident knowledge and attitudes toward POC ultrasound were also assessed using a preworkshop and postworkshop test and survey.

RESULTS

A total of 58 residents completed the workshop, and 84% were able to independently obtain high-quality images of the abdominal aorta and kidney after workshop completion, compared with 16% on the preworkshop test. Residents demonstrated a statistically significant increase in their self-reported confidence with ultrasound operation and image acquisition.

CONCLUSIONS

Training using standardized patients can prepare residents to independently obtain POC ultrasound images of the aorta and kidneys. Training resulted in increased resident confidence with POC ultrasound and self-reported likelihood of future use.

Errors in the ultrasound diagnosis of the kidneys, ureters and urinary bladder

The article presents the most frequent errors made in the ultrasound diagnosis of the urinary system. They usually result from improper technique of ultrasound examination or its erroneous interpretation. Such errors are frequent effects of insufficient experience of the ultrasonographer, inadequate class of the scanner, insufficient knowledge of its operation as well as of wrong preparation of patients, their constitution, severe condition and the lack of cooperation during the examination. The reasons for misinterpretations of ultrasound images of the urinary system may lie in a large polymorphism of the kidney (defects and developmental variants) and may result from improper access to the organ as well as from the presence of artefacts. Errors may also result from the lack of knowledge concerning clinical and laboratory data. Moreover, mistakes in ultrasound diagnosis of the urinary system are frequently related to the lack of knowledge of the management algorithms and diagnostic possibilities of other imaging modalities. The paper lists errors in ultrasound diagnosis of the urinary system divided into: errors resulting from improper technique of examination, artefacts caused by incorrect preparation of patients for the examination or their constitution and errors resulting from misinterpretation of ultrasound images of the kidneys (such as their number, size, fluid spaces, pathological lesions and others), ureters and urinary bladder. Each physician performing kidney or bladder ultrasound examination should possess the knowledge of the most frequent errors and their causes which might help to avoid them.

Standards of the Polish Ultrasound Society - update. Ultrasound examination of the kidneys, ureters and urinary bladder

The paper presents the principles of performing proper ultrasound examinations of the urinary tract. The following are discussed: preparation of patients, type of optimal apparatus, technique of examination and conditions which its description should fulfill. Urinary track examination in adults and in children constitutes an integral part of each abdominal examination. Such examinations should be performed with fasting patients or several hours after the last meal, with filled urinary bladder.

APPARATUS

Ultrasound examinations in children and infants are performed using transducers with the frequency of 5.0-9.0 MHz and in adults - with the frequency of 2.0-6.0 MHz. Doppler options are desirable since they improve diagnostic capacity of sonography in terms of differentiation between renal focal lesions.

SCANNING TECHNIQUE

Renal examinations are performed with the patients in the supine position. The right kidney is examined in the right hypochondriac region using the liver as the ultrasound "window." The left kidney is examined in the left hypochondriac region, preferably in the posterior axillary line. Ultrasound examinations of the upper segment of the ureters are performed after renal examination when the pelvicalyceal system is dilated. A condition necessary for a proper examination of the perivesical portion of the ureter is full urinary bladder. The scans of the urinary bladder are performed in transverse, longitudinal and oblique planes when the bladder is filled.

DESCRIPTION OF THE EXAMINATION

The description should include patient's personal details, details of the referring unit, of the unit in which the examination is performed, examining physician's details, type of ultrasound apparatus and transducers as well as the description proper.

Small liver nodule detection with a high-frequency transducer in patients with chronic liver disease: report of 3 cases

We report 3 cases in which small liver lesions were revealed on sonography with the supplemental use of a high-frequency transducer. In all 3 cases, the patients had cirrhosis or chronic liver disease. The lesions were not seen on computed tomography or magnetic resonance imaging. Sonography plays a pivotal role in surveillance for hepatocellular carcinoma and, with modern transducer technology, may be the first imaging modality to show an early small tumor. A more thorough search for focal liver lesions with adjunctive use of high-frequency transducers may prolong the examination time but can improve surveillance for hepatocellular carcinoma.