Harmonic waves are generated from nonlinear distortion of an acoustic signal as an ultrasound wave insonates tissues in the body. These beams are integer multiples of a fundamental transmitted frequency. Potential advantages of harmonic imaging include improved axial resolution due to higher frequencies and better lateral resolution due to narrower beams. Decreased noise from side lobes improves signal-to-noise ratios and reduces artifacts. Deleterious effects of the body wall are also reduced. The authors prospectively studied ultrasonographic (US) findings in 100 adult patients with 202 abdominal lesions by comparing harmonic US images with conventional US images. The results were subjected to statistical analysis. Harmonic imaging was superior to conventional US in regard to lesion visibility and diagnostic confidence. Harmonic imaging was particularly useful for depicting cystic lesions and those containing echogenic tissues such as fat, calcium, or air. In patients with a body mass index of 30 or more, harmonic imaging was clearly better for lesion visibility and confidence of diagnosis. The authors recommend routine use of harmonic imaging for abdominal US studies in all adult patients.

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Systematic measurements of maximum depth of penetration (DOP) of ultrasound (US) scanners are essential for quality control (QC). Conventionally, DOP measurements are performed visually and as such they could be affected by various external factors, scanner control settings, and operator related errors. Automated methods should be free of the issues associated with interoperator dependence and are an attractive alternative to the visual DOP measurements. We implement and test three automated methods for measuring DOP. The methods base their measurements on signal to noise (SNR) analysis of uniform US phantom images. Two of the methods use pairs of phantom images. The third one uses a single phantom image and an "in-air" image. The validation tests included precision, sensitivity, repeatability, and usability in routine QC application. Methods based on pairs of phantom images measure the DOP with precision +/-0.2 cm or better. Precision of the single phantom image method is +/-0.05 cm, and that method is also the most sensitive of the three. All three methods are demonstrated to be repeatable among different users. Since the images for the DOP computation are collected free-hand the sensitivity to hand-transducer motion during image acquisition was also tested. Unlike the single-phantom-image based method, the methods using image pairs were found to be very sensitive to transducer motion and therefore less convenient for clinical QC applications. In conclusion, the single-phantom-image method is best suited for routine QC in a real-life clinical practice.

Routine quality control of ultrasound scanners and transducers is important for maintaining image quality. Our experience suggests that artefact and uniformity evaluation is the most effective single phantom test for detecting equipment problems. Current methods for assessing ultrasound images for artefacts have important limitations. To overcome these limitations, we have developed a novel, low-cost, liquid phantom with a flexible surface for assessing artefacts. A range of materials were evaluated and the optimal liquid phantom was found to be a water/cornstarch solution contained within a flexible latex balloon. When compared to a rigid tissue-mimicking phantom no deficiencies in overall image appearance or artefact detection for any transducer model was observed for the liquid phantom. With minimal training, reproducible clips were obtained by clinical sonographers with low inter- and intra-operator dependence, for a range of transducers models. The flexible scanning surface of the liquid phantom allows complete rapid coupling of all transducers. Due to its ease of use and low cost this liquid phantom appears superior to rigid phantoms for assessment of non-uniformity artefacts, and should allow clinical practices to perform routine artefact assessments of all ultrasound scanners and transducers.

Our ultrasound practice is becoming even more focused on managing practice resources and improving our efficiency while maintaining practice quality. We often encounter questions related to issues such as equipment utilization and management, study type statistics, and productivity. We are developing an analytics system to allow more evidence-based management of our ultrasound practice. Our system collects information from tens of thousands of DICOM images produced during exams, including structured reporting, public and private DICOM headers, and text within the images via optical character recognition (OCR). Inventory/location information augments the data aggregation, and statistical analysis and metrics are computed such as median exam length (time from the first image to last), transducer models used in an exam, and exams performed in a particular room, practice location, or by a given sonographer. Additional reports detail the length of a scan room's operational day, the number and type of exams performed, the time between exams, and summary data such as exams per operational hour and time-based room utilization. Our findings have already helped guide practice decisions: two defective probes were not replaced (a savings of over $10,000) when utilization data showed that three or more of the shared probe model were always idle; neck exams are the most time-consuming individually, but abdomen exam volumes cause them to consume the most total scan time, making abdominal exams the better candidates for efficiency optimization efforts. A small subset of sonographers exhibit the greatest scanning and between-scan efficiency, making them good candidates for identifying best practices.

Purpose It is unclear if a 3D transducer with the special design of mechanical swing or 2D array could provide acceptable 2D grayscale image quality for the general diagnosis purpose. The aim of this study is to compare the 2D image quality of a 3D intracavitary transducer with a conventional 2D intracavitary transducer using clinically relevant phantom experiments. Methods All measurements were performed on a GE Logiq E9 scanner with both a 2D (IC5‐9‐D) and a 3D (RIC5‐9‐D) transducer used in 2D mode. Selection of phantom targets and acquisition parameters were determined from analysis of 33 clinical pelvic exams. Depth of penetration (DOP), contrast response, contrast of anechoic cylinders (diameter: 6.7 mm) at 1.5 and 4.5 cm depths in transverse planes, and in‐plane resolution represented by full‐width half‐maximum of pin targets at multiple depths were measured with transmit frequencies of 7 and 8 MHz. Spherical signal‐noise‐ratio (SNR) (diameter: 4 and 2 mm) at multiple depths were measured at 8 MHz. Results RIC5‐9‐D demonstrated <8% decrease in DOP for both transmit frequencies (7 MHz: 69.7 ± 8.2 mm; 8 MHz: 64.3 ± 7.8 mm) compared with those from IC5‐9‐D (7 MHz: 73.9 ± 4.4 mm; 8 MHz: 69.4 ± 7.8 mm). A decreased anechoic contrast was observed with a 4.5 cm depth for RIC5‐9‐D (7 MHz: 23.2 ± 1.8 dB, P > 0.05; 8 MHz: 17.7 ± 0.9 dB, P < 0.01) compared with IC5‐9‐D (7 MHz: 25.9 ± 1.2 dB; 8 MHz: 21.5 ± 0.8 dB). The contrast response and spatial resolution performance were comparable between the two transducers. RIC5‐9‐D showed comparable SNR of anechoic spheres compared to IC5‐9‐D. Conclusions 2D images from a 3D probe exhibited comparable overall image quality for routine clinical pelvic imaging.

Our goal in this work was to compare the results of common phantom tests made using matched and mixed ultrasound (US) scanner‐transducer combinations. Sets of common US quality assurance (QA) measurements were made using matched US scanner‐transducer combinations (i.e., transducers purchased for use with a particular scanner), as well as unmatched (mixed) combinations. Measurements of vertical and horizontal distance accuracy, and depth of penetration were performed using three common transducer types. Means, standard deviations, and differences between the mean mix and match measurements divided by the standard deviation (match‐mix difference, or MMD), and two‐sided, paired t‐tests were computed for the groups of mixed and matched measurements. MMDs for vertical and horizontal distance accuracy test results were less than 0.87 in all cases, well below our threshold value of 2.0, which indicates that a significant difference exists. MMDs for the depth of penetration measurements were less than 1.50, again below the threshold value. These results suggest that all of the mixed and matched data sets were very similar. The more sensitive t‐tests indicate statistically significant differences in only 2 of the 18 pairs of data sets. In conclusion, this study suggests that QA measurements generated by mixed or matched scanner‐transducer combinations are very comparable. The ability to obtain QA phantom test data from mixed scanner‐transducer combinations reduces the time required for US QA testing.PACS number(s): 87.57.–s, 87.62.+n

We evaluated a commercially available software package that uses B‐mode images to semi‐automatically measure quantitative metrics of ultrasound image quality, such as contrast response, depth of penetration (DOP), and spatial resolution (lateral, axial, and elevational). Since measurement of elevational resolution is not a part of the software package, we achieved it by acquiring phantom images with transducers tilted at 45 degrees relative to the phantom. Each measurement was assessed in terms of measurement stability, sensitivity, repeatability, and semi‐automated measurement success rate. All assessments were performed on a GE Logiq E9 ultrasound system with linear (9L or 11L), curved (C1‐5), and sector (S1‐5) transducers, using a CIRS model 040GSE phantom. In stability tests, the measurements of contrast, DOP, and spatial resolution remained within a ±10% variation threshold in 90%, 100%, and 69% of cases, respectively. In sensitivity tests, contrast, DOP, and spatial resolution measurements followed the expected behavior in 100%, 100%, and 72% of cases, respectively. In repeatability testing, intra‐ and inter‐individual coefficients of variations were equal to or less than 3.2%, 1.3%, and 4.4% for contrast, DOP, and spatial resolution (lateral and axial), respectively. The coefficients of variation corresponding to the elevational resolution test were all within 9.5%. Overall, in our assessment, the evaluated package performed well for objective and quantitative assessment of the above‐mentioned image qualities under well‐controlled acquisition conditions. We are finding it to be useful for various clinical ultrasound applications including performance comparison between scanners from different vendors.