Comparison of conventional sonography, real-time compound sonography, tissue harmonic sonography, and tissue harmonic compound sonography of abdominal and pelvic lesions

Pediatric Nephrolithiasis

The prevalence of pediatric nephrolithiasis has increased dramatically in the past two decades for reasons that have yet to be fully elucidated. Workup of pediatric kidney stones should include metabolic assessment to identify and address any risk factors predisposing patients to recurrent stone formation, and treatment should aim to facilitate stone clearance while minimizing complications, radiation and anesthetic exposure, and other risks. Treatment methods include observation and supportive therapy, medical expulsive therapy, and surgical intervention, with choice of treatment method determined by clinicians' assessments of stone size, location, anatomic factors, comorbidities, other risk factors, and preferences and goals of patients and their families. Much of the current research into nephrolithiasis is restricted to adult populations, and more data are needed to better understand many aspects of the epidemiology and treatment of pediatric kidney stones.

Ultrasound elastography for the detection of capsular fibrosis in breast implants: First results

BACKGROUND

Capsular contractures around breast implants usually develop leading to pain and aesthetically inadequate results and ultimately often requires the replacement of the implants. Textured silicone implants are the most commonly placed implant, but polyurethane-coated implants are increasingly being used in an attempt to ameliorate the long-term complications associated with implant insertion.

AIM

Capsular contracture is traditionally classified using the Baker scale, a subjective classification system based upon clinical findings. Aim of this study was to evaluate the association between pain due capsular contraction, Baker score and different techniques of US elastography.

MATERIAL AND METHODS

Patients were contacted who had undergone an implant replacement due to capsular contracture. Inclusion criterion was the re-implantation of a PU-coated implant. In the third year after changing the implant a follow-up examination was performed in 16 patients with 23 implants. A conventional examination with anamnesis, tactile and visual findings to obtain a Baker score, and ultrasound examinations including shear wave elastography, ARFI and compound elastography were performed. In addition, pain was evaluated using a visual analogue scale (VAS).

RESULTS

The pain data showed a significant improvement (before implant exchange: 4.1±2.8 score points) with significance in favor of the current state (1.7±1.0 pain score points; p = 0.002). All patients suffered from less or no pain three years after exchange of the implant. Pain values and elastography (ARFI values) correlated well (r = 0,873), with increasing Baker score the ARFI values increased. US elastography evaluations can locally determine tissue density but correlate only to a limited extent with the test findings according to Baker. US elastography values of mammary gland tissue without implant did not differ from mammary gland tissue around implants.

CONCLUSION

Preoperative Baker scores prior to exchange and the current Baker scores at the follow-up showed significantly lower score points three years after exchange of the implants. Ultrasound elastography seems to be an objective classification of capsular fibrosis. These first results motivate to initiate a prospective multicenter investigation.

Ultrasound for the Pregnant Person With Diabesity

Diabetes and obesity increase the risk of congenital anomalies, but the putative mechanisms of this increased risk are not fully elucidated. In this chapter, we delve into sonographic characteristics associated with diabetes and obesity, including fetal structural anomalies, functional cardiac alterations, and growth abnormalities. We will also discuss the technical challenges of imaging in the patient with diabesity and propose methodologies for optimizing imaging. Lastly, we will address the prevention of workplace-associated musculoskeletal disorders injury for sonographers.

Differentiation of gallbladder adenomyomatosis from early-stage gallbladder cancer before surgery

Backgrounds/Aims

This study aimed to compare the perioperative and clinical outcomes in patients undergoing laparoscopic cholecystectomy for gallbladder adenomyomatosis (GBA) or early-stage gallbladder cancer (GBC).

Methods

The perioperative and clinical outcomes of 194 patients diagnosed with GBA and 30 patients diagnosed with GBC who underwent laparoscopic cholecystectomy in our institution from January 2011 to December 2017 were retrospectively compared.

Results

There were no significant differences between the GBA and GBC groups in sex (male:female ratio 1.0:0.8 vs. 1.0:0.7, p=0.734), BMI (23.9±3.4 vs. 24.0±3.8 kg/m², p=0.916), or preoperative liver function tests. Patients in the GBC group were significantly older (50.5±14.1 vs. 65.9±10.6 years, p<0.001) and had a higher ASA grade (40.3 vs. 63.4% grade II or III, p=0.043) than patients in the GBA group. Although there was no significant difference in preoperative diagnostic methods (p=0.442), the GBC group showed a significantly higher rate of misdiagnosis on preoperative imaging compared with postoperative histopathologic findings (30.9% vs. 53.3%, p=0.011). There were significantly more patients with gallstones in the GBA group than in the GBC group (68.6% vs. 40.0%, p=0.004).

Conclusions

In older patients hospitalized for biliary colic without gallstones but with a thickened gallbladder wall with inflammation on preoperative diagnostic exam, the possibility of early-stage GBC should be considered.

Sonography of Acute Cholecystitis and Its Mimics

Right upper quadrant (RUQ) abdominal pain is a common complaint. Acute cholecystitis (AC) is the primary diagnostic consideration in most adults presenting with acute onset RUQ abdominal pain; however, a variety of other conditions can mimic AC. Abdominal ultrasound (US) receives the highest score for imaging appropriateness for these patients. This article reviews the sonographic findings of uncomplicated and complicated AC and provides practical technical tips. The radiologist should be familiar with conditions that can mimic AC, be able to suggest these alternative diagnoses when findings are present on US, and recommend additional tests or procedures, if needed.

Diagnostic accuracy of transabdominal high-resolution US for staging gallbladder cancer and differential diagnosis of neoplastic polyps compared with EUS

PURPOSE

To compare the diagnostic accuracy of transabdominal high-resolution ultrasound (HRUS) for staging gallbladder cancer and differential diagnosis of neoplastic polyps compared with endoscopic ultrasound (EUS) and pathology.

MATERIALS AND METHODS

Among 125 patients who underwent both HRUS and EUS, we included 29 pathologically proven cancers (T1 = 7, T2 = 19, T3 = 3) including 15 polypoid cancers and 50 surgically proven polyps (neoplastic = 30, non-neoplastic = 20). We reviewed formal reports and assessed the accuracy of HRUS and EUS for diagnosing cancer as well as the differential diagnosis of neoplastic polyps. Statistical analyses were performed using chi-square tests.

RESULTS

The sensitivity, specificity, PPV, and NPV for gallbladder cancer were 82.7 %, 44.4 %, 82.7 %, and 44 % using HRUS and 86.2 %, 22.2 %, 78.1 %, and 33.3 % using EUS. HRUS and EUS correctly diagnosed the stage in 13 and 12 patients. The sensitivity, specificity, PPV, and NPV for neoplastic polyps were 80 %, 80 %, 86 %, and 73 % using HRUS and 73 %, 85 %, 88 %, and 69 % using EUS. Single polyps (8/20 vs. 21/30), larger (1.0 ± 0.28 cm vs. 1.9 ± 0.85 cm) polyps, and older age (52.5 ± 13.2 vs. 66.1 ± 10.3 years) were common in neoplastic polyps (p < 0.05).

CONCLUSION

Transabdominal HRUS showed comparable accuracy for diagnosing gallbladder cancer and differentiating neoplastic polyps compared with EUS. HRUS is also easy to use during our routine ultrasound examinations.

KEY POINTS

• HRUS showed comparable diagnostic accuracy for GB cancer compared with EUS. • HRUS and EUS showed similar diagnostic accuracy for differentiating neoplastic polyps. • Single, larger polyps and older age were common in neoplastic polyps. • HRUS is less invasive compared with EUS.

Focal hepatic lesions characterisation by different sonographic techniques: a prospective analysis

INTRODUCTION

Ultrasound is usually the first diagnostic investigation for the assessment of liver lesions. Apart from conventional sonography (CS), new grey-scale sonographic techniques have been developed which have increased the application of ultrasound in liver imaging. The present study was undertaken to compare image quality of CS, real-time compound sonography (RTCS), tissue harmonic sonography (THS) and tissue harmonic compound sonography (THCS) in focal liver lesions.

MATERIALS AND METHODS

100 patients with focal hepatic lesions were enroled. Lesions were divided into solid and cystic group. Solid lesions were evaluated for lesion conspicuity and elimination of artefacts. For cystic lesions, lesion conspicuity, posterior acoustic enhancement and internal echoes within the lesion were evaluated. Grading was done using 3-5-point scales. Overall image quality was assessed depending on the total points.

RESULTS

78 solid and 22 cystic liver lesions were included. THCS showed superior results for lesion conspicuity, elimination of artefacts and overall image quality in solid lesions. RTCS showed similar results as THCS for lesion conspicuity and overall image quality in solid lesions. THS gave better results in cystic lesions for all imaging parameters. Results of THCS though slightly inferior, showed no significant difference from THS, in cystic lesions. CS was found to have least diagnostic value in characterisation.

CONCLUSIONS

For evaluation of focal hepatic lesions, a combination of compound and harmonic sonography, i.e. THCS, is the preferred sonographic technique.

What's new in urologic ultrasound?

Ultrasound is an imaging technology that has evolved swiftly and has come a long way since its beginnings. It is a commonly used initial diagnostic imaging modality as it is rapid, effective, portable, relatively inexpensive, and causes no harm to human health. In the last few decades, there have been significant technological improvements in the equipment as well as the development of contrast agents that allowed ultrasound to be even more widely adopted for urologic imaging. Ultrasound is an excellent guidance tool for an array of urologic interventional procedures and also has therapeutic application in the form of high-intensity focused ultrasound (HIFU) for tumor ablation. This article focuses on the recent advances in ultrasound technology and its emerging clinical applications in urology.

Better visualization of vermiform appendix with tissue harmonic imaging compared to conventional sonography

BACKGROUND

Surgery of appendicitis carries 7-11% negative appendectomy rates. Sonographically visualized normal appendix precludes unnecessary computed tomography (CT) examination and may reduce negative appendectomy rates. Tissue harmonic imaging (THI) has been reported to improve the overall image quality.

OBJECTIVE

We aimed to assess whether THI is more successful than conventional ultrasonography (US) in detecting normal and pathologic appendices.

PATIENTS AND METHODS

The study was performed on 185 patients who applied for routine US examinations in whom clinical findings of appendicitis were detected in 25. We searched for the appendix; applying both THI and conventional US to each patient, one before and the other after the routine US examinations. Patients were divided into two groups; one was evaluated first with conventional US and the other first with THI. When the appendix was found, localization, diameter and time spent for visualization were recorded. Twelve patients were operated; all of whom had appendicitis pathologically. Two methods were compared for: 1. Success rates in all patients; female, male and child groups separately; 2. Visualization of pathologic and normal appendices; 3. Time for visualization of appendix; 4. Comparison of success rates in the adult and child population. The relationship between the rate of visualization and body mass index was evaluated.

RESULTS

The appendix was visualized better by THI in all patients, and in the female and male groups (P < 0.001). In children, both methods were more successful compared to adults (P < 0.001, compared to male group, P < 0.001, compared to female group), with no difference between the methods (P = 0.22). When only the normal appendices were concerned, there was significant difference between both methods (P < 0.000). Both methods detected pathologic appendices better than normal ones, with a higher ratio for THI (P = 0.022 for the THI group, and χ(2) = 7.22, P = 0.07 for the conventional US group). THI visualized the appendix faster. Both methods were more successful in lean patients (P = 0.004 for THI, P = 0.001 for conventional US imaging).

CONCLUSIONS

THI visualizes appendix better than conventional US. It is a simple and time saving method that may eliminate further diagnostic imaging, and it may decrease negative appendectomy rates and related complications.

Harmonic ultrasonography for the detection of microlithiasis in the gallbladder

Purpose:

To validate the use of harmonic ultrasonography (US) in the detection of gallbladder microlithiasis.

Methods:

From November 30, 2012, to January 18, 2014, fundamental US (FUS) and harmonic US with a high background noise (HUS-N) were performed for evaluation of gallbladder during the routine abdomen US. During the US, a dot-like stone (or stones) with Brownian motion was regarded as a positive finding of microlithiasis. Fifty-five patients with microlithiasis in the gallbladder detected on US were enrolled as the subjects of a retrospective review. With respect to the obtained images, two abdominal radiologists independently scored the conspicuity of gallbladder microlithiasis on FUS and HUS-N by using a 4-grade scale. The statistical analysis employed a kappa test and a Wilcoxon rank-sum test.

Results:

For FUS, the conspicuity grades of gallbladder microlithiasis were G1 in 25 and 37, G2 in 21 and 9, G3 in 6 and 6, G4 in 3 and 3 patients, while HUS-N showed G1 in 0 and 0, G2 in 3 and 2, G3 in 12 and 15, and G4 in 40 and 38 patients, respectively, by each of the two radiologists. The kappa value was 0.633 for FUS between the two radiologists and 0.708 for HUS-N. HUS-N showed better conspicuity of gallbladder microlithiasis than FUS with significant P-values of less than 0.001 and 0.001 for the two radiologists, respectively.

Conclusion:

Compared with FUS, HUS-N enables better detection of microlithiasis in the gallbladder.

Ultrasound in chronic liver disease

Background

With the high prevalence of diffuse liver disease there is a strong clinical need for noninvasive detection and grading of fibrosis and steatosis as well as detection of complications.

Methods

B-mode ultrasound supplemented by portal system Doppler and contrast-enhanced ultrasound are the principal techniques in the assessment of liver parenchyma and portal venous hypertension and in hepatocellular carcinoma surveillance.

Results

Fibrosis can be detected and staged with reasonable accuracy using Transient Elastography and Acoustic Radiation Force Imaging. Newer elastography techniques are emerging that are undergoing validation and may further improve accuracy. Ultrasound grading of hepatic steatosis currently is predominantly qualitative.

Conclusion

A summary of methods including B-mode, Doppler, contrast-enhanced ultrasound and various elastography techniques, and their current performance in assessing the liver, is provided.

Teaching Points

• Diffuse liver disease is becoming more prevalent and there is a strong clinical need for noninvasive detection.

• Portal hypertension can be best diagnosed by demonstrating portosystemic collateral venous flow.

• B-mode US is the principal US technique supplemented by portal system Doppler.

• B-mode US is relied upon in HCC surveillance, and CEUS is useful in the evaluation of possible HCC.

• Fibrosis can be detected and staged with reasonable accuracy using TE and ARFI.

• US detection of steatosis is currently reasonably accurate but grading of severity is of limited accuracy.

Differentiating between adenomyomatosis and gallbladder cancer: revisiting a comparative study of high-resolution ultrasound, multidetector CT, and MR imaging

Objective

To compare the diagnostic performance of high-resolution ultrasound (HRUS) with contrast-enhanced CT and contrast-enhanced magnetic resonance imaging (MRI) with MR cholangiopancreatography (MRCP) to differentiate between adenomyomatosis (ADM) and gallbladder cancer (GBCA).

Materials and Methods

Forty patients with surgically proven ADM (n = 13) or GBCA at stage T2 or lower (n = 27) who previously underwent preoperative HRUS, contrast-enhanced CT, and contrast-enhanced MRI with MRCP were retrospectively included in this study. According to the well-known diagnostic criteria, two reviewers independently analyzed the images from each modality separately with a five-point confidence scale. The interobserver agreement was calculated using weighted κ statistics. A receiver operating characteristic curve analysis was performed and the sensitivity, specificity, and accuracy were calculated for each modality when scores of 1 or 2 indicated ADM.

Results

The interobserver agreement between the two reviewers was good to excellent. The mean Az values for HRUS, multidetector CT (MDCT), and MRI were 0.959, 0.898, and 0.935, respectively, without any statistically significant differences between any of the modalities (p > 0.05). The mean sensitivity of MRI with MRCP (80.8%) was significantly higher than that of MDCT (50.0%) (p = 0.0215). However, the mean sensitivity of MRI with MRCP (80.8%) was not significantly different from that of HRUS (73.1%) (p > 0.05). The mean specificities and accuracies among the three modalities were not significantly different (p > 0.05).

Conclusion

High-resolution ultrasound and MRI with MRCP have comparable sensitivity and accuracy and MDCT has the lowest sensitivity and accuracy for the differentiation of ADM and GBCA.

Precision imaging of focal liver lesions: comparison with conventional sonography in terms of image quality

OBJECTIVES

The purpose of this study was to compare the Precision Imaging sonographic technique (Toshiba Medical Systems Corporation, Tokyo, Japan) with conventional sonography of liver lesions in terms of lesion conspicuity, margin sharpness, overall image quality, and posterior enhancement.

METHODS

Sixty-nine focal liver lesions in 60 patients (age range, 14-76 years; mean age, 43 years) were prospectively evaluated. Each lesion was examined with Precision Imaging and conventional sonography. All images were reviewed and graded on a 3-point scale by 2 readers for lesion conspicuity, margin sharpness, and overall image quality. Posterior acoustic enhancement was also analyzed in cystic lesions. A Wilcoxon signed rank test was used for statistical comparisons of the techniques for all parameters.

RESULTS

Statistical analysis showed that for margin sharpness, lesion conspicuity, and overall image quality, Precision Imaging was superior to conventional sonography (P< .05). In addition, according to lesion types and dimensions, Precision Imaging was significantly superior to conventional sonography for all parameters. For posterior enhancement, there was no significant difference between Precision Imaging and conventional sonography (P ≥ .05).

CONCLUSIONS

In sonography of focal liver lesions, Precision Imaging provides better lesion conspicuity, better margin sharpness, and better overall image quality than conventional sonography. With respect to posterior enhancement of cystic lesions, Precision Imaging is not significantly different from conventional sonography. Precision Imaging may be used as a complementary method in the sonographic evaluation of focal liver lesions.

Carpal tunnel syndrome diagnosis by a self-normalization process and ultrasound compound imaging

PURPOSE

Carpal tunnel syndrome (CTS) is the common entrapment neuropathy that occurs due to compression of the median nerve at the wrist. Ultrasound images have been used to highlight anatomical variants of the median nerve, and CTS is thought to be associated to enlargement of the cross-sectional area (CSA) of the median nerve. However, there remains controversy regarding the most appropriate cutoff values of the computer measurements including the CSA, flattening ratio, and palmar bowing of median nerve, especially given that they can be influenced by image artifacts and factors that differ between individual patients. This study proposed a modified ultrasound compound imaging technique by moving fingers to reduce image artifacts, and the estimates of the normalized CSA [i.e., CSA at the wrist (CSAw) to CSA at the midforearm] with the aim of reducing discrepancies in CSA estimates and improving the ability of CTS discrimination.

METHODS

The subjects were examined with their arms supine and while they were making repetitive movements of their fingers (from an open palm into a clenched fist) within 3 s. By a commercial ultrasound scanner with a 10-MHz linear array transducer, a total of 70 images were acquired in each subject. The frame rate of ultrasound system was 25 fps. Nine frames in the acquisition sequence that had produced partial speckle decorrelation were incoherently added to form a compound image, and the inplane motion of them was corrected using the multilevel block-sum pyramid algorithm. The manual contours outlined by ten experimenters and three physicians were used to test the performance in determining the boundary of the median nerve. The receiver operating characteristic (ROC) curve was used to evaluate the usefulness of the estimates in distinguishing healthy volunteers from CTS patients.

RESULTS

The manual contours of the median nerve in the compound images had an average area overlap exceeding 90% and relatively small area errors. The areas under the ROC curve obtained using the CSAw estimates for the original and compound images were 0.60 ± 0.09 (mean ± standard error) and 0.80 ± 0.05, respectively; that using normalized CSA estimates for the original and compound images were 0.76 ± 0.04 and 0.89 ± 0.04, respectively. The results show that variations in the CSAw values of compound images for healthy overweight and obese subjects can adversely influence CTS diagnosis, but that this can be overcome using the normalized CSA estimate of compound images.

CONCLUSIONS

Compound imaging provides images of superior quality for determining the location of the median nerve boundary. Using the normalized CSA estimate would assist in eliminating problems associated with variability between populations, since the subject becomes his or her own internal control, thereby improving the ultrasound-based diagnosis of CTS.

Differentiation of adenomyomatosis of the gallbladder from early-stage, wall-thickening-type gallbladder cancer using high-resolution ultrasound

OBJECTIVES

To evaluate the diagnostic performance of transabdominal high-resolution ultrasound (HRUS) for differentiation of adenomyomatosis from early-stage, wall-thickening-type gallbladder (GB) cancer.

METHODS

HRUS was defined as the addition of high megahertz imaging to conventional low megahertz imaging with use of state-of-the-art imaging technology. HRUS findings were retrospectively compared in 45 patients with adenomyomatosis and 28 patients with stage T1/T2 wall-thickening-type GB cancer. For evaluating HRUS performance in the differential diagnosis of adenomyomatosis from GB cancer, receiver operating characteristic curve analysis was used with a five-point confidence scale independently scored by three blinded radiologists who also analysed morphological abnormalities.

RESULTS

The area under the receiver operating characteristic curve (A (z)) values of HRUS in the diagnosis of adenomyomatosis were 0.948, 0.915 and 0.917 for reviewers 1, 2 and 3. Symmetrical wall thickening, intramural cystic spaces, intramural echogenic foci and twinkling artefacts were significantly associated with adenomyomatosis (P < 0.05), whereas irregular thickening of the outer wall, focal innermost hyperechoic layer (IHL) discontinuity, IHL irregularity, IHL thickening greater than 1 mm, loss of multilayer pattern in the GB wall, and intralesional vascularity were significantly associated with cancer (P < 0.05). The sensitivity, specificity and accuracy of intramural cystic spaces/echogenic foci for the diagnosis of adenomyomatosis were 80.0 %, 85.7 % and 82.2 %.

CONCLUSIONS

This study showed that HRUS can be helpful for distinguishing adenomyomatosis from early-stage, wall-thickening-type GB cancer.

Comparative sonographic appearance of nephroliths and associated acoustic shadowing artifacts in conventional vs. spatial compound imaging

Spatial compound sonography improves visualization of tissue details and allows clearer delineation of structural margins. Improved image clarity is due to reduced speckling artifact; however, other types of acoustic shadowing artifacts may be unchanged or variably altered when conventional and spatial compound sonographic images are compared. Because intrarenal distal shadowing artifacts in conventional sonographic images are oftentimes the first or only evidence that a nephroliths is present, we compared the appearance and associated artifacts of nephroliths examined with both imaging modes. Consensus evaluation by two evaluators confirmed differences in appearance of nephroliths based on imaging mode. Nephroliths with conventional imaging mode were less hyperechoic and had better margin delineation while nephroliths were more hyperechoic and had less distinct margins with spatial compound imaging mode. Distal acoustic shadowing artifacts were present in 43% of spatial compound imaging mode vs. 86% of conventional imaging mode. When present in both imaging modes, intensity of these artifacts was weaker and the distance traveled was shorter in spatial compound imaging mode. Multiple diverging acoustic shadowing artifacts originating from a single source, the nephroliths were occasionally noted in spatial compound but not conventional imaging mode. These results demonstrate that the absence of distal acoustic shadowing cannot be used to exclude the presence of a nephrolith in dogs and cats. Optimal diagnosis of nephroliths, margin delineation, and visualization of the distal renal parenchyma requires paired radiography and sonography, and alternating between sonographic imaging modes is therefore suggested.

Evaluation of the accuracy of articular cartilage thickness measurement by B-mode ultrasonography with conventional imaging and real-time spatial compound ultrasonography imaging

The present study aimed to quantify the thickness of articular cartilage (Tc) in vitro using both conventional and real-time spatial compound B-mode ultrasonography (US) with a clinically used transducer and to evaluate the accuracy of measurement by comparing the results with values obtained microscopically. Femoral condyle samples were obtained from a 6-month-old pig and a 3-year-old pig. B-mode US images with conventional imaging and real-time spatial compound imaging (RTSCI) of osteochondral blocks were acquired. Tc determined using US (Tc-US) was measured from line data parallel to US beam direction acquired from B-mode images with an objective method for determining cartilage surface and bone-cartilage interfaces at the peak brightness values. Tc was also determined under microscopy (Tc-optical) using the corresponding points from US measurement. Tc-US was compared with Tc-optical to assess accuracy. Tc-US correlated significantly with Tc in both conventional imaging and RTSCI (r = 0.961, 0.976, respectively). Bland-Altman plots showed mean differences between Tc-optical and Tc-US were -0.0073 mm and 0.0139 mm with standard deviations of 0.171 mm and 0.131 mm for conventional imaging and RTSCI, respectively. Our results show that Tc-US measurement using B-mode US allows accurate measurement of Tc. Considering correlation coefficients between Tc-US and Tc-optical, RTSCI US may offer higher accuracy for measuring Tc than conventional methods when an objective tissue border determination algorithm is used, even though both showed good accuracy in our study.

Role of Structural Imaging in Lymphoma

The lymphomas, Hodgkin lymphoma and non-Hodgkin lymphoma, are among the most common types of cancer in the United States. Imaging plays an important role in the evaluation of patients with lymphoma, because it aids in treatment planning and in the determination of prognosis. Structural imaging entails the assessment of morphologic features of normal tissues and organs of the body and of malignant lesions within these structures, and plays a major role in the noninvasive assessment of lymphoma. This article reviews cross-sectional structural imaging modalities with an emphasis on computed tomography and magnetic resonance imaging, with some mention of ultrasonography.

Fade-out sign on hepatic tissue harmonic compound sonography: a value as a new sign in the diagnosis of fatty liver

OBJECTIVE

To evaluate the value of the fade-out sign in the diagnosis of fatty liver (FL) on hepatic ultrasound (US).

METHODS

We evaluated 127 patients who underwent hepatic US, including 70 patients with FL and 57 normal control subjects. US images were qualitatively evaluated for the presence of the fade-out sign. This sign was considered present if there was a dark band on the deep portion of the liver on the harmonic image when compound sonography (CS) was converted to tissue harmonic CS mode. The degrees of FL were classified into mild, moderate, and severe. The distribution of lengths of dark bands in three groups was examined, and a multiple comparison of the average dark band length was carried out using one-way ANOVA.

RESULTS

The fade-out sign was seen in 55 of 70 FL patients (78.6%) compared to 3 of 57 control subjects (5.3%) (p<0.001). The sensitivity, specificity, accuracy, and positive predictive value of the fade-out sign for the US diagnosis of FL were 78%, 94%, 85.8%, and 94.8%, respectively. Among the 70 FL, there were 28 mild FL (mean length of dark band; 8.3 mm±8.2), 31 moderate FL (mean; 28 mm±6.3), and 11 severe FL (mean; 51 mm±8.3). There were significant differences in band length according to severity (p<0.01).

CONCLUSION

The fade-out sign on hepatic harmonic US was frequently present in FL. As fat infiltration increased, the fade-out sign lengthened. The fade-out sign offers a specific and new sign of FL.

Real time spatial compound ultrasound in the evaluation of meniscal injuries: a comparison study with conventional ultrasound and MRI

The aim of this study was to compare real time spatial compound ultrasound (RTCS) and conventional ultrasound with MRI in the evaluation of meniscal injuries. Thirty five patients with clinical suspicion of meniscal injury underwent ultrasound of knee alternating between conventional and compound sonography followed by MRI of the knee on a 1.5 T MR system. The images were compared for their quality and ability to detect meniscal tear. Compound ultrasound significantly improved definition of soft tissue planes, reduced speckle and other noise, improved contrast resolution (p value<0.05) with improved confidence in detection of tears in doubtful cases. Interobserver variability was seen only for conventional ultrasound and the sensitivity, specificity, accuracy were 83.3%, 87.5% and 85.7% for the first observer and 80%, 87.5% and 84.3% for second observer. For compound ultrasound it was same for both the observers with sensitivity, specificity and accuracy being 90% each. Although compound ultrasound improves image quality in the evaluation of meniscal injuries the benefit with respect to detection of tears is only marginal. It is a valuable tool for screening the patients before MRI and we recommend that instead of conventional ultrasound, compound ultrasound should be routinely used for sonographic evaluation of meniscal injuries.

Contrast-enhanced harmonic compound US of the spleen to increase staging accuracy in patients with Hodgkin lymphoma: a prospective study

PURPOSE

To prospectively compare contrast material-enhanced harmonic compound ultrasonography (US), computed tomography (CT), and fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) in detecting nodular infiltration in the spleen of patients with newly diagnosed Hodgkin lymphoma.

MATERIALS AND METHODS

After institutional review board approval and informed consent, 100 consecutive patients with Hodgkin lymphoma during pretreatment staging were prospectively investigated for possible spleen involvement by comparing harmonic compound US (integrated with intravenous infusion of microbubbles in 33 patients) with CT and FDG PET. Findings indicative of malignant nodules with the imaging procedures were regarded as lymphoma infiltration; in case of discrepancy, response to treatment was regarded as evidence of lymphoma.

RESULTS

Malignant nodules were detected with CT in 13 patients, with FDG PET in 13 patients, and with contrast-enhanced harmonic compound US in 30 patients. Coincidental findings of malignancy with all three imaging techniques occurred in 13 patients; 17 patients had only US-detectable malignant nodules, which showed disappearance or relevant decrease after chemotherapy. Overall, the spleen had nodular infiltration in 30 patients (13 for imaging finding concordance; 17 for typical contrast-enhanced harmonic compound US findings and chemotherapy-related nodule size modifications). Thus, both CT and FDG PET provided false-negative results in 17 of 30 patients compared with contrast-enhanced harmonic compound US, the results of which translated into disease upstaging in 13 patients.

CONCLUSION

Harmonic compound US with contrast enhancement for the characterization of possible nodules provides a higher sensitivity than does CT or FDG PET in the detection of splenic involvement by Hodgkin lymphoma.

Understanding the Advanced Signal Processing Technique of Real-Time Adaptive Filters

Diagnostic ultrasound manufacturers are advancing the technology of sonographic systems, providing superior image quality and improving the diagnostic confidence for both sonographers and radiologists. Real-time adaptive filters (RTAFs) are perhaps the least known among the advanced signal processing techniques available on most modern sonography machines, which is further complicated by the fact that RTAF appears under various trademark names. Despite the different proprietary names, RTAFs generally employ a postprocessing mathematical algorithm to real-time imaging that improves contrast resolution by reducing noise and artifacts while simultaneously enhancing the edges and smoothing the tissue texture of structures. This technique may be applied across a wide variety of clinical examinations and may not yet be completely understood and appreciated by sonographers. This review aims to educate readers on how RTAFs work, supported by examples of their benefit to image quality. In particular, the authors describe the effectiveness of using RTAF for superficial structures (thyroid, abdominal wall), deep structures (abdomen, pelvis), and dynamic examinations, including musculoskeletal and vascular applications.

New technologies applied to ultrasound diagnosis of sports injuries

INTRODUCTION

The aim of this study was to compare the ultrasound images of different soft tissue lesions from two different portable sonography devices: a conventional portable sonography device (ultrasound [US]-A, Micromaxx model; Sonosite Inc., Bothell, WA, USA), and a recently marketed compact device (US-B, Logiq e; General Electric Healthcare, Wauwatosa, WI, USA). The US-B device uses the new technologies of tissue harmonic imaging, real-time compound ultrasound, panoramic view, three-dimensional imaging, and virtual convex imaging.

METHODS

We compared ultrasound images of six different types of soft tissue lesions (muscle contusion, muscle strain, patellar tendinosis, calcifying patellar tendinosis, rupture of the lateral internal ligament of the knee, and deep infrapatellar synovial bursa), from six different subjects. Analysis of images was performed by the same ultrasound specialist. In accordance with the classical criteria for ultrasound studies, the following quantitative indicators and parameters of ultrasound quality were used to evaluate the images: degree of echogenicity, size of the lesion area, aspect, shape, borders, and overall visualization.

RESULTS

In muscle lesions due to contusion, not only is the edematous area better visualized with the new system, but definition of hemorrhagic area borders and their content is especially increased. In lesions of the tendons, the new system affords better definition of the borders of the hypoechogenic area of tendinous degeneration and perfect visualization of the extension of the damaged area using a panoramic study. Sonographic study of ligaments with chronic lesions permits visualization of scar areas. Finally, use of the new system with a small synovial bursa shows the content of the bursa and thickness of the walls more clearly.

CONCLUSION

Overall, the quantitative indicators and parameters of image quality performed in this study of common sports lesions demonstrate the improvement in visualization of damaged soft tissues with the new technologies now incorporated into portable sonography devices.

Correlation of transabdominal sonographic and cystoscopic findings in the diagnosis of focal abnormalities of the urinary bladder wall: a prospective study

OBJECTIVE

The aim of this study was to prospectively assess the diagnostic capabilities of transabdominal sonography performed with newer sonography machines for showing focal bladder wall abnormalities (FBWAs) detected on cystoscopy.

METHODS

One hundred twelve consecutive patients (97 male and 15 female; mean age, 68 years) underwent cystoscopy. Reasons for referral were macroscopic hematuria (44 cases [39%]), surveillance after transurethral resection (56 cases [49.5%]), and incidental sonographic findings (12 cases [11.5%]). One to 2 days before cystoscopy, sonography was carried out by a single operator who was blinded to clinical and recent sonographic findings. The presence, size, number, and location of FBWAs (eg, polypoid vegetations and asymmetric bladder wall thickening) were recorded and compared with cystoscopic and histologic findings.

RESULTS

One hundred ten patients with a histologic diagnosis were available for the study. Benign conditions, nontransitional tumors, and transitional tumors were found in 26.3%, 3.7% and 70% of the patients, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of sonography of cystoscopic lesions were 91.4%, 79.3%, 91.4%, 79.3%, and 88.2%. Cancers of 15 mm or smaller and flat tumors were often missed by sonography, whereas chronic cystitis accounted for most of the false-positive sonographic findings; however, sonography had poor capability of characterizing FBWAs, with specificity of 62%. In this respect, color Doppler findings proved of little aid as well.

CONCLUSIONS

In patients selected for cystoscopy, transabdominal sonography with newer sonography machines showed good diagnostic accuracy for focal alterations of the bladder wall found on cystoscopy.

The benefits of comparing conventional sonography, real-time spatial compound sonography, tissue harmonic sonography, and tissue harmonic compound sonography of hepatic lesions

This study aimed to compare conventional sonography, tissue harmonic imaging (THI), spatial compound sonography (SONOCT), and SONOCT+THI for overall image quality, lesion conspicuity, and elimination of artifacts of hepatic lesions. Forty-five patients were randomly selected, and 51 different hepatic lesions were scanned using each of the four techniques. The combined images of SONOCT+THI exhibited the best image quality for solid and cystic lesions, while conventional images were the worst for most hepatic lesions (P<.001). SONOCT was the best for fatty liver.

Enhancing Image Quality Using Advanced Signal Processing Techniques

The main expectation of a sonographer is to obtain images of diagnostic quality. This requires the fundamental knowledge of spatial, contrast, and temporal resolution. To help determine which of these parameters needs to be optimized, one needs a well-defined clinical approach. Once satisfactory imaging is achieved, advanced signal processing tools can then be applied to further enhance image quality beyond that of good acoustic windows and tissue paths. Spatial compounding and tissue harmonic imaging are two commonly used tools that have significant clinical relevance in diagnostic sonography. These tools have their own unique applications and benefits, as well as limitations. When used correctly, they have shown to significantly improve image quality, allowing for the possibility of increased accuracy and an improvement in diagnostic confidence.

Phase inversion harmonic imaging improves assessment of renal calculi: a comparison with fundamental gray-scale sonography

PURPOSE

To compare phase inversion harmonic imaging (PIHI) with fundamental imaging (FI) in the evaluation of renal calculi.

METHODS

Thirty adult patients with renal calculi (17 men, 13 women; mean age 44 years [range, 25-71]) underwent transabdominal sonographic examination of the urinary system. Both kidneys and renal calculi were examined with PIHI and FI. Overall renal conspicuity, calculus visibility, and clarity of posterior shadowing were assessed subjectively using a 4-point scale (0 being the worst, 3 being the best). The maximum diameter of the calculi was measured using both techniques. The effect of body mass index on qualitative scoring and quantitative measurements was evaluated.

RESULTS

PIHI improved overall renal conspicuity compared with FI (p < 0.001). The visibility of the calculi and clarity of posterior shadowing were significantly better with PIHI than with FI (p < 0.001 for both parameters). The maximum diameter of calculi was larger with PIHI than with FI (p < 0.001). The superiority of PIHI over FI regarding overall conspicuity of the kidney, visibility of the calculus, and clarity of posterior shadowing scores increased in the obese group (p < 0.001 for all 3 parameters). The mean calculus diameter difference between the 2 techniques was significantly higher in the obese group.

CONCLUSION

The routine use of PIHI is recommended in the evaluation of renal calculi.

Ultrasonography of the pancreas. 2. Harmonic imaging

Tissue harmonic imaging (THI) is a relatively new ultrasonographic imaging modality which has been implemented in many modern scanners. As several previous studies have pointed out, THI can help to overcome some shortcomings of conventional B-mode ultrasonography (US). The aim of this article is to give a compact summary of the potentials of THI, focused on pancreatic imaging. Beginning with a recapitulation of the technical background of THI, the particularities and suitable applications of THI in US of the pancreas are discussed. Examination protocols and typical indications are presented together with example images. Finally, new trends and developments in B-mode sonography of the pancreas such as panorama US, compound imaging, and photopic US are mentioned.

Recent advances in ultrasound technology

Technical improvements have made profound changes in diagnostic ultrasound imaging. Some of these changes, such as encoded pulses and receive focusing, occur in the background and are essentially nonadjustable. Others, including harmonics and compounding, are real-time options and are adjustable by the imager. New technologies that offer great promise for improved characterization of lesions include contrast ultrasound and elastography. This article will attempt to update the small animal imager on the clinical applications of these newer technologies.

Can High-Attenuation Renal Cysts Be Differentiated from Renal Cell Carcinoma at Unenhanced CT?

PURPOSE

To retrospectively determine if renal cell carcinoma can be differentiated from high-attenuation renal cysts at unenhanced computed tomography (CT) based on Hounsfield unit measurements and heterogeneity.

MATERIALS AND METHODS

The Human Investigation Committee at our institution approved this study with waiver of informed consent. This study was compliant with the HIPAA. Fifty-four pathologically proved renal cell carcinomas in 54 patients (36 men and 18 women; average age, 53 years; range, 23-90 years) and 56 high-attenuation renal cysts in 51 patients (30 men and 21 women; average age, 63 years; range, 28-86 years) were retrospectively evaluated at unenhanced CT. Two independent readers reviewed randomized unenhanced CT images and obtained Hounsfield unit readings of each mass. A subjective determination of lesion heterogeneity was also performed by using a four-point scale (1: homogeneous, 2: mildly heterogeneous, 3: moderately heterogeneous, 4: markedly heterogeneous). Statistical analysis was performed by using Bland-Altman regression tree, classification and regression tree, and Shapiro-Wilk normality test.

RESULTS

The average attenuation of cysts for reader 1 was 53.4 HU (range, 23-113 HU) and for reader 2 was 53.8 HU (range, 21-108 HU). The average attenuation of neoplasms for reader 1 was 34.7 HU (range, 21-60 HU) and for reader 2 was 38.4 HU (range, 22-60 HU). For cyst heterogeneity, a score of 1 was given in 55 of 56 (98%) cysts for reader 1 and in 53 of 56 (95%) cysts for reader 2. For neoplasm heterogeneity, a score of 1 was given in 35 of 54 (65%) neoplasms for reader 1 and in 36 of 54 (67%) for reader 2. Given the distribution of cyst and tumor attenuation values and lesion heterogeneity, a homogeneous mass measuring 70 HU or greater at unenhanced CT has a greater than 99.9% chance of representing a high-attenuation renal cyst.

CONCLUSION

The findings from this study may help differentiate high-attenuation renal cysts from renal cell carcinomas at unenhanced CT and may suggest the next appropriate imaging study for definitive characterization.

ULTRASOUND IMAGE COMPOUNDING: EFFECT ON PERCEIVED IMAGE QUALITY

In order to determine the effect of different image compounding functions on perceived image quality, 84 pairs of ultrasound images were collected, mixed, and reviewed by four independent observers who were asked to identify the highest quality image of each pair. Each image in a pair was made using the same orientation, transducer, frequency, and gain settings but different compounding settings. Outcomes were analyzed using logistic regression. Observers judged compound images to be better quality than noncompound images in 69% cases, the same quality in 24%, and poorer quality in 7%. Overall, compound images were considered significantly better quality than noncompound images (P < 0.001). Compound images were more likely to be considered better quality than the corresponding noncompound images when combined transmit/receive spatial compounding was used rather than receive-only spatial compounding or transmit compounding, and when the vector transducer or the curvilinear transducer were used rather than the linear transducer. Observers considered improved border definition and increased signal to noise ratio to be the properties that accounted most often for higher quality of compound images compared with noncompound images.

Comparison of fundamental sonography, tissue-harmonic sonography, fundamental compound sonography, and tissue-harmonic compound sonography for focal hepatic lesions

Image qualities of fundamental, tissue-harmonic, fundamental compound, and tissue-harmonic compound sonography for evaluating focal hepatic lesions were compared. Two radiologists, blinded to the type of techniques and to the final diagnosis, independently evaluated 384 images of 96 hepatic lesions: hemangiomas (n=35), hepatic cystic lesions (n=28), cirrhosis-related nodules (n=22), focal nodular hyperplasia (n=1), and metastases (n=10). All images were graded in terms of lesion conspicuity, margin sharpness, and overall image quality using a 4- or 5-point scale. In the cases of cystic lesions, posterior acoustic enhancement and internal artifacts were also analyzed. A Friedman test was used for multiple statistical comparisons of the four techniques for all parameters. Compound imaging was significantly superior to fundamental imaging regarding lesion conspicuity, margin sharpness, and overall quality (P<0.05). For posterior enhancement and internal artifacts within the cyst, harmonic ultrasonography (US) was significantly better than fundamental US (P<0.05). For evaluating focal hepatic lesions on US, compound imaging provided better lesion conspicuity, better margin sharpness, and better overall image quality than fundamental imaging did. Tissue harmonic imaging also provided better posterior enhancement and fewer internal artifacts of the cyst than fundamental imaging.

A practical approach to analyzing focal lesions in the liver

Ultrasound evaluation of patients with hepatic masses should extend beyond basic lesion detection to characterization and clinical management. A systematic approach for hepatic lesion evaluation using ultrasound makes it possible to triage patients and, in many cases, leads to definitive diagnosis that may eliminate the need for additional imaging.

ULTRASONOGRAPHIC ANATOMY OF THE NORMAL CANINE CALCANEAL TENDON

To provide a series of detailed ultrasonographic images of the canine calcaneal tendon, greyhound cadaver pelvic limbs were scanned with a high-resolution transducer, and images compared with dissected specimens. The three components of the calcaneal tendon are the tendons of insertion of the gastrocnemius, superficial digital flexor, and a conjoined tendon formed by tendons from the biceps femoris, semitendinosus, and gracilis. Each of these three tendons was visible in transverse ultrasound images, each measuring 2.4-3.2-mm thick at mid-calcaneal tendon. Improved understanding of the anatomy of the calcaneal tendon will support clinical ultrasonography of this region.

Recent advances in the sonographic assessment of vascularity and blood flow in gynecologic conditions

OBJECTIVE

This overview presents recent advances in sonographic depiction of vascularity and blood flow in the uterus, ovaries, and breasts. Enhanced sonographic visualization and evaluation of intraorgan vascularity has resulted from improved image processing and display. Future advances, such as the use of contrast enhancement, are also mentioned in this overview as one of many topics for future investigation.

STUDY DESIGN

This is an overview of the topic based on review of the literature and the authors' experience.

RESULTS

Specifically, the sensitivity of color Doppler sonography has been enhanced with the use of amplitude or power Doppler techniques. Spatial depiction of vascularity has improved because of 3-dimensional and "live 3-dimensional" processing.

CONCLUSION

The combination of more sensitive color Doppler sonography and 3-dimensional imaging provides both anatomic and physiologic assessment of the vascularity and blood flow of the ovary, uterus, and breast.

ULTRASONOGRAPHIC ANATOMY OF THE CANINE ELBOW

To produce detailed ultrasonographic images of the soft tissue structures around the canine elbow joint, a series of greyhound cadaver limbs were scanned both intact and dissected in a water bath. Suitable transducer positions and bone landmarks are described and the ultrasonographic appearance of the lateral collateral ligament, anconeal process, triceps tendon, origin of olecranon ligament, biceps tendon insertion, medial collateral ligament, and medial coronoid process are illustrated. Improved understanding of the anatomy of the canine elbow will support clinical ultrasonography of this region.

Transabdominal pulse inversion harmonic imaging improves assesment of ovarian morphology in virgin patients with PCOS: comparison with conventional B-mode sonography

OBJECTIVE

In virgin policystic ovary syndrome (PCOS) patients transabdominal sonography is the preferential method of the pelvic examination. The purpose of this study was to determine ovarian morphology by the transabdominal route by pulse inversion harmonic imaging (PIHI) in virgin PCOS patients and to compare the diagnostic image quality with conventional B-mode ultrasonography (CBU).

METHODS

Fifty-two ovaries in 26 virgin patients were evaluated by the transabdominal approach. Each ovary was examined using both PIHI and CBU. The sharpness of the follicular cysts walls, degree of internal echo definitions of the follicle cysts and overall ovarian conspicuity was assessed subjectively, using 4 point scoring (0, being worst; 3, being best score). The number of countable follicles, the size of largest and smallest ovarian follicle and ovarian volumes were assessed quantitively by both techniques. The effect of body mass index (BMI) on qualitative and quantitative scoring was evaluated.

RESULTS

The sharpness of the cyst wall and internal echo structure was significantly better with PIHI than with CBU (P < 0.001 P < 0.001 and P < 0.001, respectively). PIHI improved overall ovarian conspicuity in 41 (78.8%) of 52 examination. The number of countable follicles was significantly lower with CBU (P < 0.001). The maximum diameter of the largest follicle was larger with PIHI sonography to compared CBU (P < 0.001). Mean ovarian volume was significantly larger with CBU (P < 0.001). When data were analyzed separately according to BMI, number of non-diagnostic overall ovarian conspicuity scores with CBU was markedly high in obese patients (88% with CBU versus 3.8% with PIHI). On the other hand, mean number of countable follicles with CBU became much more lower in the obese group (P < 0.001).

CONCLUSION

In virgin PCOS patients, when compared to transabdominal CBU, PIHI significantly improved the detection of ovarian follicles, especially in high BMI obese subjects, through increased contrast sensitivity for cystic structures and decreased intrafollicular artifactual echoes. Transabdominal ultrasonographic examination by PIHI mode can contribute to the evaluation of ovaries.