Phase-inversion tissue harmonic imaging compared with conventional B-mode ultrasound in the evaluation of pancreatic lesions

The aim of this study was to compare the diagnostic sensitivity, specificity, and image quality of conventional B-mode US (BM) and phase-inversion tissue harmonic imaging (PTHI) regarding pancreatic pathology. In a prospective study, 107 patients, aged between 28 and 85 years, underwent US examinations of the pancreas with both BM and PTHI in a randomly chosen order. As diagnostic reference, either contrast-enhanced CT or MRI examinations of the upper abdomen were obtained in all patients. Sensitivity and specificity were evaluated using the Students t test. Differences in overall image quality, lesion conspicuity, fluid–solid differentiation, and delineation of the pancreatic tail were analyzed using Wilcoxons signed ranks test and Bowkers symmetry test. Sixteen of 107 examined patients (15%) were non-diagnostic and excluded due to technical limitations such as abdominal gas. A total of 60 pancreatic lesions (cysts, acute pancreatitis, dilatation of the pancreatic duct, calcifications, and solid tumors) were diagnosed by CT or MRI. Phase-inversion tissue harmonic imaging had a higher sensitivity of 70% (14 of 20) than BM (60%; 24 of 40) for the detection of pancreatic lesions; however, the difference was not statistically significant (p=0.46). In the assessment of lesions <1 cm of size, PTHI had a sensitivity of 70% and BM 46.7%, whereby the difference again was not statistically significant. Phase-inversion tissue harmonic imaging proved to be superior to BM regarding overall image quality (p<0.0001), lesion conspicuity (p=0.0045), and fluid–solid differentiation (p=0.0002), as well as the delineation of the pancreatic tail (p<0.0001). These differences were statistically significant. The statistically significant improvement of image quality with regards to lesion conspicuity, fluid–solid differentiation, and delineation of the pancreatic tail favors the use of PTHI when evaluating the pancreas with US. Sensitivity for pancreatic lesions is increased with PTHI in comparison with conventional sonography (BM), especially in lesions <1 cm in diameter, although the difference was not statistically significant.     

Phase-inversion tissue harmonic imaging compared to fundamental B-mode ultrasound in the evaluation of the pathology of large and small bowel

Our purpose was to compare phase-inversion harmonic imaging (PIHI) with conventional B-mode ultrasound (US) regarding image quality in the evaluation of bowel pathology. Forty-one patients prospectively underwent intestinal ultrasound scans with US and PIHI in randomly chosen order. Crucial technical parameters were standardized. Bowel morphology as well as perienteric pathology and complications were documented. In 24 cases, the ultrasound results were compared to those of other imaging modalities. Three radiologists evaluated (1) overall image quality, (2) lesion conspicuity and diagnostic confidence, and (3) detection of free fluid on hardcopy films. The ratings for image quality were compared using the two-sample paired t test for means and Bowkers test for symmetry (p=0.05). Compared to US, PIHI provided significantly better overall image quality, lesion conspicuity and diagnostic confidence, as well as better detection of free fluid (p< 0.05). Bowel wall pathology, detected by both modalities, showed good correlation to additional imaging modalities. In 12 patients (29.3%), a gain of crucial diagnostic information was observed with PIHI when compared to US. PIHI significantly enhances sonography of the intestine by offering better overall image quality, better visualization of bowel pathology and associated changes. Additionally, PIHI adds crucial diagnostic information in several patients.     

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.     

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

OBJECTIVE: The purpose of this study was to compare conventional sonography, real-time spatial compound sonography, tissue harmonic sonography, and tissue harmonic sonography merged with compound sonography for overall image quality, lesion conspicuity, and elimination of artifacts. SUBJECTS AND METHODS. In this study, 150 lesions in 122 randomly selected patients with various abdominal and pelvic lesions were evaluated. For each lesion, sonograms were obtained with four techniques: conventional sonography, real-time spatial compound sonography, tissue harmonic sonography, and tissue harmonic compound sonography. All images were reviewed and graded independently by two observers for overall image quality, lesion conspicuity, and elimination of artifacts. RESULTS: Statistical analysis showed that for overall image quality, lesion conspicuity, and elimination of artifacts, tissue harmonic compound sonography was significantly superior to all of the other techniques; real-time spatial compound sonography was better than tissue harmonic sonography; and conventional sonography was the least valuable of all (p < 0.001). When data were analyzed separately according to lesion types, tissue harmonic compound sonography was significantly superior for revealing stone diseases, liver cysts, gallbladder polyps, and uterine myomas. For the remainder of lesion groups, spatial compounding was superior to tissue harmonic sonography for all aspects of evaluation, and conventional sonography was the least valuable (p < 0.05). CONCLUSION: In abdominal and pelvic scanning, tissue harmonic compound sonography provides the best overall image quality, best lesion conspicuity, and least artifacts of all the evaluated imaging modes. Spatial compound sonography is better than tissue harmonic sonography for the evaluation of lesions in general, despite some differences among lesion groups.     

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.     

Suspected rotator cuff lesions: tissue harmonic imaging versus conventional US of the shoulder

PURPOSE: To compare tissue harmonic imaging (THI) of the shoulder with conventional ultrasonography (US) in patients suspected of having rotator cuff lesions. MATERIALS AND METHODS: THI and conventional US images were obtained in 50 patients suspected of having rotator cuff lesions. Images were graded for visibility of acromioclavicular (AC) joint surfaces and rotator cuff tendon contours and substances: Grade 1 meant poor; grade 2, moderate; and grade 3, good visibility. Accuracy, sensitivity, and specificity of the diagnosis of AC joint osteoarthritis and accuracy of the diagnosis and rates of underestimation and overestimation of the extent of rotator cuff tears were evaluated. Visibility grade differences were evaluated with the Wilcoxon signed rank test. The McNemar test was used to assess differences in diagnoses. Magnetic resonance (MR) arthrography was the reference standard. RESULTS: Mean visibility grades for readers 1 and 2, respectively, were as follows: for AC joint bone surfaces, 2.1 and 2.0 with THI and 1.7 (P =.010) and 1.7 (P =.16) with conventional US; for AC joint capsule surfaces, 2.2 and 1.9 with THI and 1.8 (P =.005) and 1.8 (P =.34) with US; for supraspinatus tendon contour, 2.6 and 2.2 with THI and 2.1 (P =.001) and 1.9 (P =.055) with US; for supraspinatus tendon substance, 2.2 and 1.9 with THI and 2.0 (P =.036) and 1.7 (P =.070) with US; for subscapularis tendon contour, 2.4 and 2.1 with THI and 2.2 (P =.07) and 2.0 (P =.25) with US; and for subscapularis tendon substance, 1.8 and 1.7 with THI and 2.0 (P =.86) and 1.7 (P =.91) with US. Diagnostic accuracies for the supraspinatus tendon for readers 1 and 2, respectively, were 84% and 74% with THI and 86% and 70% with US (P >.99 for both readers). Corresponding values for the subscapularis tendon were 78% and 72% with THI and 64% (P =.27) and 52% (P =.006) with US. CONCLUSION: Joint and tendon surface visibility improves with THI, as compared with the visibility achieved with conventional US. THI is superior to conventional US for diagnosis of subscapularis tendon abnormalities.     

Perfusion imaging of the kidney using contrast-enhanced phase-inversion ultrasound

PURPOSE: We evaluated different techniques of contrast-enhanced phase-inversion ultrasound to visualize renal perfusion. MATERIALS AND METHODS: Levovist contrast-enhanced phase-inversion ultrasound with different levels of mechanical index and frame rate was performed in 20 kidneys. Analysis using a software algorithm for time-resolved perfusion imaging was compared to single-image analysis performed by three independent radiologists. RESULTS: Optimal depiction of renal perfusion was achieved only by using a mechanical index which was high enough to destroy the microbubbles of the contrast agent (burst imaging) combined with a low frame rate (0.5 images/second). Renal cortex and medulla showed a homogeneous enhancement. Computer-assisted time-resolved perfusion analysis was applicable; it did not show additional Information to single-image analysis. CONCLUSION: Renal perfusion can be visualized using contrast-enhanced phase-inversion ultrasound. For depiction of bigger vessels, it is equal to B-mode ultrasound or Doppler mode techniques; however, it is superior for visualization of renal parenchymal perfusion.     

Diagnostic accuracy of diffusion-weighted imaging in differentiating benign from malignant ovarian lesions

Purpose

To clarify the diagnostic accuracy of diffusion‐weighted imaging (DWI) in differentiating benign from malignant ovarian lesions.

Materials and Methods

We retrospectively analyzed magnetic resonance images of 123 ovarian lesions in 119 patients. We defined lesions with abnormal signal intensity as malignancy and assessed the location of abnormal intensity within the lesions on DWI. We also assessed the mean and lowest apparent diffusion coefficient (ADC) values of the solid portion for each ovarian lesion.

Results

The majority of malignant ovarian tumors and mature cystic teratomas, and almost half of the endometriomas, showed abnormal signal intensity on DWI, whereas most fibromas and other benign lesions did not. The main locations of abnormal signal intensity were solid portions in malignant ovarian tumors, cystic components suggestive of keratinoid substances and Rokitansky protuberance in mature cystic teratomas, and intracystic clots in endometriomas. On DW imaging, receiver‐operating characteristic analysis yielded mean Az values of 0.703. There was no significant difference in mean and lowest ADC values between malignant and benign lesions.

Conclusion

DWI of ovarian lesions and ADC values of the solid component are not useful for differentiating benign from malignant ovarian lesions. This knowledge is essential in avoiding misinterpretation in the diagnosis of ovarian lesions. J. Magn. Reson. Imaging 2008;28:1149–1156. © 2008 Wiley‐Liss, Inc.     

Early postoperative tissue harmonic sonography of the thyroid gland

PURPOSE: Fundamental gray-scale imaging (FGI) is known to be unuseful for thyroid imaging in the early postoperative setting. Thus, we evaluated the feasability of tissue harmonic imaging (THI) early after thyroid resection. MATERIAL AND METHODS: FGI and THI of the neck were performed in 48 consecutive patients 4 days after surgery. The examiner was blinded to patient diagnoses and types of surgery. FGI and THI examinations were stored on videotape and reviewed offline by two different readers who rated the quality of delineation of the organ borders and presence or absence of focal lesions. The results were compared to neck US performed 12 weeks after surgery. RESULTS: Delineation of the thyroid remnants in THI/FGI was rated to be excellent in 22/2, good in 11/9, poor in 3/16 and not visible at all in 4/13 patients. The correlation between THI-volumetry and control-volumetry was very high (r=0.81; p<0.0001). THI but not FGI depicted presence or absence of solid thyroid nodules with 100% accuracy. CONCLUSION: THI is a feasible method for thyroid US in the early postoperative setting. It permits volumetry of the residual thyroid tissue and accurately depicts nodules within the thyroid remnant.     

低场磁共振FLAIR序列对脑部疾病的诊断价值

目的探讨低场磁共振FLAIR序列对脑部病变的诊断准确性，并与常规T2WI序列比较。方法120例经手术病理或临床证实的脑部病变患者均经低场磁共振FLAIR序列与常规T2WI序列检查，对获自两种技术的病灶检出率及病灶内部结构与边缘的显示程度进行了比较。结果在120例的262个脑部病变中，FLAIR序列的检出率为98．5％（258／262），而常规T2WI序列为82．4％（216／262）；FLAIR序列良好显示病灶内部结构与边缘比例为66．3％（171／258），而常规T2WI序列仅为13．4％（29／216），二者有显著性差异（P〈0．01）。结论在低场MRI中，FLAIR序列显示脑皮层、皮层下和脑室旁病灶的敏感性明显高于常规T2WI序列，且能获得更多的病理信息。     

Transabdominal pulse inversion harmonic imaging improves assessment 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.     

超声弹性成像在浅表软组织局灶性病变诊断中的应用

目的 探讨超声弹性成像技术在浅表软组织局灶性病变诊断中的临床应用价值.方法 收集在我院就诊并手术的浅表软组织局灶性病变65例,并对其行实时超声弹性成像检查,根据病灶软硬度不同进行评分,并与术后病理进行分析.结果 良性病灶超声弹性图中良性囊肿病变以红绿蓝相间为多,良性实质性病变以1～3分多见,而恶性病变以4～5分多见.两组病变的弹性评分情况比较差异具有统计学意义（P＜0.01）.以≥4分作为判断恶性病变的标准,其敏感度为84％,特异度为90％,准确率为88％.结论 超声弹性成像对浅表软组织局灶性病变良恶性病变的鉴别诊断提供有价值的信息.     

Magnetic resonance imaging of hepatic focal lesions: dynamic contrastographic evaluation with gadolinium versus reticulo-endothelial hepato-specific contrast media

PURPOSE: To compare the potentials of AMI-25 (Endoren) to those of Gadolinium with the dynamic contrast-enhanced technique in the differential diagnosis of focal liver lesions. MATERIAL AND METHODS: Forty patients with at least one focal liver lesion diagnosed at US underwent MRI. We used a 1.5 T unit and employed single-shot half-Fourier T2-weighted FSE and spoiled gradient-echo T1-weighted sequences before and after Gadolinium injection. Multiple acquisitions were obtained during the arterial, portal and delayed phases. Twenty-four to 48 hours later T2*-weighted GRE and SPGR/90 degrees sequences were obtained after AMI-25 administration. In the characterization of solid lesions the gold standard was biopsy performed with a shearing needle; for the diagnosis of angiomas and of 11 metastatic lesions we considered follow-up and clinical data as important diagnostic elements. RESULTS: We found 12 hepatocarcinomas, 14 metastases, 4 cases of focal nodular hyperplasia (FNH), 4 adenomas and 6 angiomas. The diagnosis was correct and confirmed by the conventional examination in all cases but 2 adenomatous lesions and 2 angiomas. Precontrast studies showed slight hyperintensity in 2 of 4 cases of FNH, while the other 2 lesions appeared isointense and were therefore detected only on postcontrast images, where there was contrast agent uptake during the arterial phase and rapid washout. We found only one central scar hyperintense on T2- and hypointense on T1-weighted images. After AMI-25 administration all lesions appeared isointense to surrounding parenchyma on T2* GRE sequences. Adenomas were isointense in the precontrast phase and postcontrast 3 of them showed strong Gadolinium uptake and rapid washout. After AMI-25 two of the 4 lesions were hyperintense while the other two were isointense to the parenchyma. Four of 6 angiomas exhibited a typical pattern characterized by signal hyperintensity on T2-weighted sequences and on AMI-25-enhanced T1- and T2-weighted sequences. Two angiomas were supposed to be of malignant nature but histology showed the presence of a strong fibrotic component. Hepatocarcinomas could be detected on precontrast images. After Gadolinium administration 10 lesions appeared hyperintense in the arterial phase and 2 were hypointense. After AMI-25 all lesions exhibited homogeneous signal hyperintensity and appeared slightly bigger than on Gadolinium-enhanced images. The metastases were only partly demonstrated by MRI. Postgadolinium studies showed 13 lesions with hyperintense signal in the portal phase. AMI-25 administration detected 14 lesions that appeared slightly bigger than on Gadolinium-enhanced images. CONCLUSIONS: AMI-25 can help also in characterizing primary lesions with an atypical signal pattern after contrast agent administration thanks to its intrinsic capability of accumulating in benign lesions. However it remains difficult to characterize well differentiated hepatocarcinomas and adenomas. Finally, AMI-25 improves MR capabilities in detecting secondary lesions and possible satellite nodules.