Focal and diffuse liver disease studied by quantitative microstructural sonography

Quantitative microstructural sonography differs from conventional sonography in several ways. The frequency as well as the amplitude of echoes is recorded and assessed using spectral analysis techniques. The effects of diffraction of the ultrasound beam are calibrated, as are the transfer characteristics of the system. Studies of patients with alcoholic liver disease revealed significantly increased attenuation, heterogeneity of scatterers, and local scattering strength in those with severe disease; in contrast, patients with mild cirrhosis exhibited decreased local scattering strength compared to normal individuals. Using retrospective three-parameter discriminant analysis, 23 out of 24 patients were successfully categorized, suggesting that the parameters used were capable of measuring microstructural changes associated with these disease states. Parameters varied widely among 6 types of hepatic tumors, suggesting that this method may offer promise in distinguishing tumors from normal cases and alcoholic liver disease as well as from each other. Further applications and evaluation of this method appear justified.     

Oral cholecystography vs gallbladder sonography: a prospective, blinded reappraisal

In a prospective, blinded study of 205 patients, oral cholecystography (OCG) and sonography were compared in terms of how well each screened patients for gallbladder diseases. Among 23 patients who had pathologic confirmation of the diagnosis at cholecystectomy, OCG correctly diagnosed 20 cases (87%) while sonography diagnosed 18 (78%). Among 54 patients with an abnormal OCG and/or sonogram, OCG detected 47 (87%) while sonography detected 44 (81%). These small differences in detection rates were not statistically significant. On the basis of these results, we cannot conclude that either sonography or OCG has a diagnostic advantage in screening patients for gallbladder disease. The large numbers of false-negative examinations found on both sonography and OCG suggest that in a patient with persistent symptoms, the alternative study should be performed if the first examination is negative.     

Comparison of CT and sonography in the diagnosis of acute appendicitis: a blinded prospective study

OBJECTIVE: Our objective was to compare the accuracy of CT and sonography in a general community teaching hospital for the diagnosis of acute appendicitis in patients with suspected acute appendicitis. SUBJECTS AND METHODS. In this prospective study, 199 consecutive patients with clinical signs and symptoms of acute appendicitis were examined with sonography (graded compression technique) and CT (focused unenhanced single-detector helical CT [5-mm section thickness]. CT was performed from the L2 vertebral body to the pubic symphysis, and no patients were given oral, rectal, or IV contrast medium. The primary sonographic criterion for diagnosing acute appendicitis was an incompressible appendix with a transverse outer diameter of 6 mm or larger with incompressible periappendicular inflamed fat with or without an appendicolith. The primary CT criterion for diagnosing acute appendicitis was the identification of an appendix with a transverse outer diameter of 6 mm or larger with associated periappendiceal inflammatory changes. The results, independently reported, were correlated with surgical and histopathologic findings. RESULTS: One hundred thirty-two patients had acute appendicitis at surgery, and 67 patients did not. The sensitivity of CT and sonography was 76% and 79%, respectively; the specificity was 83% and 78%; the accuracy was 78% and 78%; the positive predictive value was 90% and 87%; and the negative predictive value was 64% and 65%. CONCLUSION: Unenhanced focused single-detector helical CT and graded compression sonography performed in a general community teaching hospital by both body imaging radiologists and general radiology staff members have a similar accuracy for the diagnosis of acute appendicitis.     

Value of contrast-enhanced sonography for the characterization of focal hepatic lesions in patients with diffuse liver disease: receiver operating characteristic analysis

OBJECTIVE: Our aim was to assess the diagnostic performance of contrast-enhanced agent detection sonographic imaging to characterize focal hepatic lesions in patients with diffuse liver disease in comparison with baseline sonographic images and to determine whether agent detection imaging can reduce the necessity of further diagnostic workup for lesion characterization. MATERIALS AND METHODS: Contrast-enhanced sonography using 4 g of Levovist at a concentration of 300 mg/mL was performed on 75 focal hepatic lesions in 75 patients with diffuse liver disease. Interval reviews for both baseline without and with contrast-enhanced sonography were performed independently by two radiologists. They were requested to determine the malignity of focal hepatic lesions using a 5-point confidence level and to record the specific diagnoses and the necessity for further imaging for lesion characterization. Radiologists' performances for lesion differentiation using baseline and contrast-enhanced sonography were evaluated using receiver operating characteristic (ROC) analysis. Interobserver agreement was also analyzed. RESULTS: When contrast-enhanced sonography was used, ROC analysis revealed a significant improvement for both reviewers (area under the receiver operating characteristic curve [A(z)] = 0.753 and 0.830 and 0.971 and 0.974 at baseline sonography and contrast-enhanced sonography, respectively; p < 0.002) for differentiating malignant and benign focal liver lesions. Contrast-enhanced sonography also improved specificity from 12% to 91% for reviewer 1 and from 26% to 85% for reviewer 2 compared with baseline sonography. Furthermore, excellent interobserver agreement was achieved for contrast-enhanced sonography (weighted kappa = 0.919), whereas only good agreement was achieved for baseline sonography (weighted kappa = 0.656). A better result for specific diagnosis was obtained by contrast-enhanced sonography (79% and 75%) than by baseline sonography (37% and 48%, p < 0.05). Contrast-enhanced sonography (72% and 63%) outperformed baseline sonography (35% and 28%, p < 0.05) as a confirmatory imaging technique. CONCLUSION: Contrast-enhanced agent detection sonography can be used to characterize focal hepatic lesions in patients with diffuse liver disease reliably and with a higher diagnostic confidence than baseline sonography. Furthermore, contrast-enhanced sonography reduced the need for further diagnostic workups for focal hepatic lesion characterization.     

Emission tomography for assessment of diffuse alcoholic liver disease.

A method of quantitative liver tomoscintigraphy (SPECT) was compared for accuracy with planar scintigraphy (PS) in a group of patients with diffuse alcoholic liver disease. SPECT sensitivity was also compared with that of transmission computed tomography (CT), US, aminopyrine breath test (ABT) and liver chemistries (LC). One hundred and fourteen alcoholic patients with proven liver disease and 17 patients free of liver disease were included. Seven quantitative scintigraphic features and a score, including all criteria were considered. With a specificity of 95%, the sensitivity was 79% in steatosis and 97% in cirrhosis. SPECT showed a better sensitivity than PS (SPECT 89%, PS 66%), especially in patients with steatosis. In the same subsets of patients, SPECT sensitivity also compared favorably with that of transmission CT (SPECT 92%, CT 65%), ultrasonography (SPECT 88%, US 53%) and ABT (SPECT 90%, ABT 63%).     

Renal allografts: prospective analysis of Doppler sonography

Fifty-six consecutively transplanted renal allografts were prospectively evaluated with serial Doppler sonographic examinations. Thirty-eight episodes of transplant rejection in 32 patients (63% proved pathologically) and 24 episodes of acute tubular necrosis (ATN) in 24 patients were encountered. The Doppler spectral waveform was characterized by means of the pulsatility index (PI), systolic/diastolic ratio (SDR), diastolic/systolic ratio (SDR), diastolic/systolic ratio (DSR), and resistive index (RI). Accuracy was optimized with use of top normal values as follows: PI = 1.8, SDR = 4.0, DSR = 0.25, RI = 0.75. There were no significant differences in the indices for those patients undergoing rejection versus those with ATN. The sensitivity for predicting transplant rejection was adversely affected by the history of either ATN or a previous rejection episode in the same allograft. Comparison with concurrent radionuclide examinations revealed similar sensitivities for rejection with scintigraphy and sonography. Differentiation of ATN from rejection was more reliable with scintigraphy than with sonography.     

Transvaginal and transabdominal sonography: prospective comparison

Transvaginal (TV) and transabdominal (TA) sonography were compared in a prospective study. A total of 230 examinations (126 pelvic, 104 pregnancy) were performed on 215 patients, ranging in age from 14 to 80 years. The improved anatomic detail on TV scans yielded new information in 138 (60%) examinations and better visualization of pelvic structures in 51 (22%) examinations. There was no important difference in diagnostic information provided by the two imaging modalities in 36 (16%) cases, and TV images were worse in five (2%). The clinical diagnosis was altered on the basis of TV sonographic findings in 54 (24%) cases and confirmed with certainty in 166 (72%). Diagnostic problems posed by TA scanning were not resolved by TV scanning in ten (4%) instances. Statistical analysis indicated that TV scanning was significantly better than TA scanning in the visualization of gestational sac contents (P less than .005), detection of fetal heart motion (P less than .001), and evaluation of the endometrial canal in the retroverted or retroflexed uterus (P less than .001). TV scanning was significantly better than TA scanning in visualization of the ovaries in patients with uterine leiomyomas (P less than .005) but not significantly better in peri- and postmenopausal patients (P greater than .05).     

MR imaging of diffuse liver disease

MR imaging is able to demonstrate and distinguish the full variety of benign and malignant diffuse liver diseases.     

经颈静脉肝穿刺活检术在弥漫性肝病中的临床应用价值

目的:探讨经颈静脉肝穿刺活检术(TJLB)在弥漫性肝病中的临床应用价值.方法:回顾性分析2019年6月-2020年11月在我院接受TJLB的35例弥漫性肝病患者的病例资料,对一般资料、技术成功率、组织学标本充分性、手术操作时间、穿刺次数、并发症发生率等情况进行分析.结果:10例凝血酶原时间延长>6 s,25例国际标准化...     

Computed tomography. Focal and diffuse liver disease

Contrast enhanced CT is very accurate in the detection of focal hepatic disease. Lesion characterization is a more complex issue, in some instances requiring a combination of CT and other diagnostic tests or biopsy for accurate diagnosis. Although CT remains the modality of choice in the evaluation of suspected focal hepatic disease, this role may change if progress in MR imaging leads to further improvements in lesion detection and characterization.     

Ultrasonography and computed tomography in diffuse liver disease with cholestasis

Ultrasonography (US) and computed tomography (CT) were performed on respectively 67 and 42 (altogether 72) patients, for the assessment of intrahepatic cholestasis. The diagnostic ability to differentiate between malignant (17 patients) and benign (55 patients) liver disease was analyzed. Coarse echogenicity of the liver led to inconclusive results in differentiating between cirrhosis (2 out of 29 patients) and malignant infiltration (4 out of 15 patients) by US. Other benign liver diseases in 23 patients, including acute hepatitis, chronic active hepatitis, fatty liver, and liver congestion, were correctly interpreted as benign. CT correctly disclosed malignant liver disease in all cases. A false positive diagnosis of malignancy was encountered in 4 (out of 17) patients with decompensated hepatic cirrhosis because of non-homogeneous expansive areas on CT in 3 cases. The true cause was in 2 patients non-uniform fatty infiltration, and in one patient with acute hepatitis A, small hypodense lesions. Among cholestatic patients, decompensated cirrhosis and malignant liver infiltration could not always be differentiated on US or CT.     

Quantitative US attenuation in normal liver and in patients with diffuse liver disease: importance of fat

Two methods are used to estimate ultrasound attenuation in liver. These were based on amplitude change and frequency change as a result of depth dependent attenuation. Evaluation of the two methods against a family of calibrated phantoms yielded correlation coefficients of 0.98 and 0.99, respectively. Liver attenuation in 26 control subjects was 0.50 and 0.52 dB/MHz/cm, respectively. Liver attenuation was estimated in 50 patients who later underwent liver biopsy. Comparison with quantitative histologic results showed that the presence of fat alone accounted for the increased attenuation associated with cirrhosis. Similar high attenuation values were found in patients with fatty infiltration. Fibrosis alone did not result in elevated liver attenuation. Cirrhotics without fatty infiltration had attenuation similar to that of the controls. Mechanisms of action are discussed.     

MRI of diffuse liver disease: characteristics of acute and chronic diseases

Diffuse liver disease, including chronic liver disease, affects tens of millions of people worldwide, and there is a growing need for diagnostic evaluation as treatments become more readily available, particularly for viral liver diseases. Magnetic resonance imaging (MRI) provides unique capabilities for noninvasive characterization of the liver tissue that rival or surpass the diagnostic utility of liver biopsies. There has been incremental improvement in the use of standardized MRI sequences, acquired before and after administration of a contrast agent, for the evaluation of diffuse liver disease and the study of the liver parenchyma and blood supply. More recent developments have led to methods for quantifying important liver metabolites, including lipids and iron, and liver fibrosis, the hallmark of chronic liver disease. Here, we review the MRI techniques and diagnostic features associated with acute and chronic liver disease.Magnetic resonance imaging (MRI) provides superior characterization of disease processes and masses in the liver compared with computed tomography (CT) (1) but requires attention to details regarding the optimal technique needed to achieve this relative performance. Routine MRI examination of the liver should include both single shot T2-weighted and breath-hold T1-weighted images (2), as well as gadolinium enhancement with the acquisition of multiple phases. The T1-weighted precontrast images must include in-phase and out-of-phase acquisitions to assess hepatic lipid or iron content. T1-weighted pre- and postgadolinium enhanced images are acquired using a fat-suppressed three-dimensional gradient-echo (3D GRE) sequence (3). These images are most commonly acquired in the axial plane with approximately 2 mm in-plane resolution and 2–3 mm resolution in the z-axis. Using various acceleration techniques, including parallel processing and under sampling, 3D GRE images covering the entire liver from the lung bases to below the kidneys can be acquired under 15 s during a single breath hold. Dynamically enhanced postgadolinium images are acquired to characterize tumors and diffuse liver disease. The timing of the arterial phase images is critical to providing unique diagnostic information for determining the perfusion characteristics of hepatic lesions and revealing hemodynamic changes related to active liver disease. The venous and delayed recirculation phase images, sometimes referred to as “equilibrium” phase images, are used for detecting other characteristic features delineating different tumor types and for grading hepatic fibrosis related to chronic liver disease. In chronic liver disease, dynamic postgadolinium images are critical for the detection and characterization of regenerative or dysplastic nodules and hepatocellular carcinoma. The same sequences that are useful for liver evaluation allow the comprehensive evaluation of all soft tissues of the abdomen and the depiction of most of the important diseases, and thus, they facilitate the use of a universal protocol for abdominal imaging.Various etiologies have been described for diffuse liver disease (4). This review article discusses acute and chronic liver disease processes in light of the MRI features and techniques that are used for the evaluation of diffuse liver diseases.     

Ultrasonography and scintigraphy of the liver in focal and diffuse disease

In a clinical series the accuracy of standard colloid scintigraphy and gray-scale ultrasonography in investigations for liver disease was evaluated. The results of 246 investigations in which both methods were utilized were reviewed and classified according to diagnosis and follow-up. In focal disease the sensitivity was 0.90 for scintigraphy, and 0.83 for ultrasonography; ultrasonography had the higher specificity, 0.94 compared with 0.77 for scintigraphy. In diffuse disease the sensitivity was found to be low for both methods, about 0.60, while specificity was high, 0.86 for scintigraphy and 0.92 for ultrasonography. Decreased liver function in diffuse liver disease as reflected by bone marrow uptake at scintigraphy was not found to have any influence on the degree of sensitivity of ultrasonography.     

Comparison of liver histology with ultrasonography in assessing diffuse parenchymal liver disease

To establish the accuracy of ultrasonography in assessing diffuse parenchymal liver disease we performed a prospective comparative study with histology in 50 patients with a wide range of liver disease. Liver biopsy was performed within 24 h of the ultrasound examination and ultrasonography was performed by a single operator who was unaware of clinical details of the patients. Histology was reviewed blind and the degree of steatosis graded mild, moderate or severe while increased portal fibrous tissue was graded mild, moderate or established cirrhosis. Thirty-six patients had steatosis and 31 patients had increased fibrous tissue on histology. Ultrasonography correctly identified steatosis in 32/36 (89%) patients including all patients with the severe grade. Increased fibrous tissue was correctly identified in 24/31 (77%) with a sensitivity of 100% in patients with moderate fibrosis and established cirrhosis. Specificity was 93% for steatosis and 89% for increased fibrous tissue. These results show that ultrasonography can provide a non-invasive prediction of liver histology which in moderate and severe steatosis and advanced fibrosis can be both highly sensitive and specific.     

Ultrasonography of liver. Technique and focal and diffuse disease

Because of its widespread use and availability, ultrasonography is frequently the first test used to assess patients with focal or diffuse hepatic disease. While ultrasonographic features of hepatic lesions often do not allow for a specific diagnosis, this article demonstrates typical ultrasonographic features of commonly encountered disease entities as an aid to differential diagnosis. Recent advances, including Doppler and intraoperative ultrasonography also are discussed.