Improved characterization of liver lesions with liver-phase uptake of liver-specific microbubbles: prospective multicenter study

PURPOSE: To evaluate in a prospective multicenter study whether conventional ultrasonographic (US) characterization of liver lesions can be improved by imaging during the liver-specific phase of SH U 508A uptake in the microbubble-specific agent detection imaging mode. MATERIALS AND METHODS: One hundred forty-two patients with liver lesions underwent conventional gray-scale and color Doppler US and SH U 508A-enhanced US. Two radiologists blindly read digital cine clips and assigned scores for confidence in diagnosis of benignancy or malignancy, diagnosis of specific lesion types, and relative difference in SH U 508A uptake between the lesion and the liver parenchyma (ie, subjective conspicuity score [SCS]). Comparisons were made to see whether the addition of agent detection imaging led to improved diagnostic performance. RESULTS: Receiver operating characteristic analysis revealed improved discrimination of benign and malignant lesions for readers 1 (P =.049) and 2 (P <.001). The number of patients with a correct diagnosis of benignancy or malignancy assigned by readers 1 and 2, respectively, improved from 114 and 113 to 125 and 128 with agent detection imaging (reader 1: P =.027; reader 2: P =.008; McNemar test). Specific diagnoses were made more accurately with agent detection imaging: At McNemar testing, the number of correct lesion type determinations increased from 83 to 92 (P =.022) for reader 1 and from 85 to 99 (P <.001) for reader 2. Both readers assigned high scores for differences in SH U 508A uptake between the liver parenchyma and the lesion for metastases and cholangiocarcinomas and low scores for uptake differences in most of the benign lesions. Hepatocellular carcinomas (HCCs), hemangiomas, and adenomas had more variable uptake differences. Fourteen of 22 hemangiomas were assigned an SCS of less than 50%, and 22 (reader 1) and 15 (reader 2) of 31 HCCs were assigned an SCS of greater than 50%. CONCLUSION: With use of SH U 508A-enhanced agent detection imaging, liver lesion characterization and diagnostic performance are significantly improved.     

Statistical validation of brain tumor shape approximation via spherical harmonics for image-guided neurosurgery

RATIONALE AND OBJECTIVES: Surgical planning now routinely uses both two-dimensional (2D) and three-dimensional (3D) models that integrate data from multiple imaging modalities, each highlighting one or more aspects of morphology or function. We performed a preliminary evaluation of the use of spherical harmonics (SH) in approximating the 3D shape and estimating the volume of brain tumors of varying characteristics. MATERIALS AND METHODS: Magnetic resonance (MR) images from five patients with brain tumors were selected randomly from our MR-guided neurosurgical practice. Standardized mean square reconstruction errors (SMSRE) by tumor volume were measured. Validation metrics for comparing performances of the SH method against segmented contours (SC) were the dice similarity coefficient (DSC) and standardized Euclidean distance (SED) measure. RESULTS: Tumor volume range was 22,413-85,189 mm3, and range of number of vertices in triangulated models was 3674-6544. At SH approximations with degree of at least 30, SMSRE were within 1.66 x 10(-5) mm(-1). Summary measures yielded a DSC range of 0.89-0.99 (pooled median, 0.97 and significantly >0.7; P < .001) and an SED range of 0.0002-0.0028 (pooled median, 0.0005). CONCLUSION: 3D shapes of tumors may be approximated by using SH for neurosurgical applications.     

Ultrasmall pulmonary opacities on multidetector-row high-resolution computed tomography: a prospective radiologic-pathologic examination

OBJECTIVE: To clarify the pathologic findings of ultrasmall pulmonary opacities (5 mm or smaller in diameter) found on multidetector-row high-resolution computed tomography (MD-HRCT). METHODS: Ten lobes in 10 patients were included in this study. Each lobe had a primary lung tumor and was removed surgically. Two thoracic radiologists noted any tiny nonlinear opacity on preoperative MD-HRCT films (1.25-mm thickness) covering the whole lobe. Pathologic findings of detected opacities were evaluated macroscopically and microscopically. RESULTS: Among 139 ultrasmall opacities 5 mm or smaller in diameter, 94 corresponded to normal anatomic structures (partial volume averaging or motion artifact), 36 corresponded to pathologic abnormalities, and 9 were unidentified. Histologic diagnoses of 36 pathologic abnormalities were inflammatory lesions (n = 16), intrapulmonary lymph nodes (IPLN; n = 7), atypical adenomatous hyperplasia (AAH; n = 7), bronchioloalveolar carcinoma (BAC; n = 5), and another neoplastic lesion (n = 1). CONCLUSION: Tiny pulmonary lesions, such as AAHs, BACs, and IPLNs, were identified among ultrasmall opacities found on MD-HRCT.     

Superficial esophageal cancer: esophagographic findings correlated with histopathologic findings

PURPOSE: To retrospectively determine and evaluate the findings of superficial esophageal cancer at esophagography and to correlate the esophagographic findings with the depth of tumor invasion. MATERIALS AND METHODS: The institutional review boards required neither their approval nor informed patient consent for this retrospective study. One hundred thirteen patients with superficial esophageal cancer who underwent esophagectomy at three institutions were included in this study. Double-contrast esophagograms were reviewed independently by two reviewers. For assessment of histopathologic findings, pathology reports were reviewed. Findings at esophagography, including morphologic type of the lesion, lesion extent, presence or absence of elevated or depressed component, margin and extent of elevated or depressed component, presence or absence of nodularity, extent of nodularity, esophageal luminal narrowing, and esophageal wall rigidity, were compared between mucosal and submucosal cancers by using chi2, Fisher exact, and independent-sample t tests. RESULTS: Of 122 histopathologically proved superficial esophageal cancers in 113 patients, 100 (82%) were detected at esophagography. The most common morphologic type was the plaquelike form; 50 (50%) such lesions were depicted at esophagography. Morphologic types were significantly different between the mucosal and submucosal cancers (P < .001). Protruded and plaquelike lesions were more frequent among submucosal cancers, whereas most flat lesions were mucosal cancers. An elevated component (P < .001), a rigid esophageal wall (P < .001), and a lobulated or irregular margin of the elevated component (P = .023) were significantly more frequent among submucosal cancers. Also, total extent of the lesion (P < .001), size of the largest nodule (P < .001), and extent of nodularity (P = .036) were significantly larger in the submucosal cancers. CONCLUSION: In the evaluation of patients with superficial esophageal cancer, esophagography appears to be helpful for diagnosing the tumor and differentiating mucosal from submucosal cancers.     

Severe acute respiratory syndrome: prognostic implications of chest radiographic findings in 52 patients

PURPOSE: To retrospectively assess prognostic implications of radiographic findings in severe acute respiratory syndrome (SARS). MATERIALS AND METHODS: Radiographic findings were reviewed by two radiologists for 52 patients with SARS. On each radiograph, each lung was separated into upper, middle, and lower zones. A four-point scale was used to score extent of SARS-related lesions in each zone; points from all zones were added for a cumulative score. Patient sex, age, comorbidities, duration of developing lesions, lesion score for each radiograph, need for mechanical ventilation, and percentage of lung affected were compared between patients who died (n = 20) and survivors (n = 32). Continuous and categorical variables were analyzed with Mann-Whitney test and Fisher exact or chi(2) test, respectively. RESULTS: Survival and mortality groups showed no significant differences with respect to patient sex, duration of SARS-related lesions, development of lesion shifting, and acute respiratory distress syndrome. Patients who died were significantly older (mean +/- standard deviation, 56.9 years +/- 17.2 vs 40.4 years +/- 16.6; P =.002) and had higher frequency of comorbid lung illnesses (nine of 20 vs two of 32, P =.001), maximal lesion extent score of 7 or higher (20 of 20 vs five of 32, P <.001), involvement of four or more lung zones (17 of 20 vs four of 32, P <.001), bilateral lung involvement (19 of 20 vs 14 of 32, P <.001), need for mechanical ventilation (18 of 20 vs two of 32, P <.001), and higher percentage of affected areas (41.5% +/- 8.6 vs 16.4% +/- 10.0, P <.001) than those of survivors. CONCLUSION: On chest radiographs, maximal SARS-related lesion extent score of 7 or higher is a strong predictor of mortality, especially in patients with comorbid lung illnesses and involvement of four or more lung zones.     

Role of subvoxel free fluid on diffusion parameters in brain tissue with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy and its correlation with physical disability: histogram analysis of standard and fluid-attenuated MR diffusion

BACKGROUND AND PURPOSE: Subcortical signal intensity abnormalities and lacunar infarcts are the radiologic hallmark of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. MR diffusion studies reveal abnormalities in lesions and also within normal appearing white matter. To further characterize the underlying pathologic abnormality, we evaluated the role of subvoxel free fluid in brain with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy on diffusion parameters and physical disability and analyzed the interrelation between diffusion variables and nonlacunar T2 lesion load. METHODS: Mean diffusivity maps from fluid-attenuated and standard diffusion images of 13 patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy and seven age-matched control participants were compared by means of histogram analysis for three tissue compartments (whole brain parenchyma, normal appearing brain tissue, and nonlacunar lesions) by using a semiautomated region growing algorithm to define whole brain parenchyma and lesions on fluid-attenuated images. RESULTS: In both patients and control participants, the average mean diffusivity of whole brain parenchyma was lower on fluid-attenuated than on standard images (P <.001). Average mean diffusivity and peak location for all compartments were significantly elevated in patients (P <.001) and higher for lesions than for normal appearing brain tissue on both types of images (P <.001). The difference between standard and fluid-attenuated average mean diffusivity of normal appearing brain tissue, reflecting the subvoxel free fluid content, was elevated in patients (P <.05) and correlated closely with the Rankin score (Spearman's rank correlation coefficient = 0.889, P <.001). Average mean diffusivity of whole brain parenchyma and normal appearing brain tissue correlated strongly with the nonlacunar T2 lesion load (Pearson's correlation coefficient = 0.743-0.928, P <.005). CONCLUSION: This study shows that standard diffusion measurements are contaminated by free fluid partial volume effects for patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy and for control participants. It also provides evidence of a clinical significance of increased subvoxel free fluid in normal appearing brain with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, which may be more important than either global atrophy, increased diffusivity or, T2 lesion load.     

Degree of hippocampal atrophy is related to side of seizure onset in temporal lobe epilepsy

BACKGROUND AND PURPOSE: Temporal lobe epilepsy (TLE) is associated with pathologic changes in hippocampal physiology and morphology. Our aim was to quantify volume reduction of the right and left hippocampus in patients with TLE and to investigate whether the degree of hippocampal atrophy is related to the side of seizure onset. METHODS: The volume of the right and left hippocampus was estimated for 50 controls and 101 patients with TLE, by applying the unbiased Cavalieri method on MR images. RESULTS: Pairwise comparisons, within a multivariate analysis of variance and adjusted by using the Bonferroni correction, revealed that both right and left hippocampal volumes were, on average, significantly smaller in patients with right-sided seizure onset (R-patients) relative to those of controls (P < .001 and P = .04, respectively). Furthermore, left hippocampal volume was significantly smaller in patients with left-sided seizure onset (L-patients) compared with controls (P < .001), but the right-sided hippocampal volume was not significantly smaller (P = .71). Moreover, a correlation analysis revealed that the strong linear association between the right and left hippocampal volumes existing in the control population (r = 0.73) is partially lost in patients with TLE (r < or = 0.48), and this loss in correlation appears to be more pronounced in L-patients than in R-patients. CONCLUSION: Our MR imaging results suggest that although the major damage in patients with TLE is located in the hippocampus ipsilateral to the side of seizure onset, R-patients are more likely to have bilateral hippocampal volume reduction. These findings support the hypothesis that cerebral hemispheres may not only differ in their functionality organization but also in their vulnerability to a neurologic insult.     

Factors predicting successful needle-localized breast biopsy

RATIONALE AND OBJECTIVES: The purpose of this study was to identify factors that predict successful removal of nonpalpable breast lesions with mammography-guided needle-localized breast biopsy. MATERIALS AND METHODS: Of the 455 consecutive patients referred for needle-localized breast biopsy of one or more nonpalpable breast lesions between January 1990 and December 1994, 272 (59.8%) had sufficiently complete data to be included in this study. Medical charts, pathology laboratory reports, wire-placement mammograms, and radiographs of specimens from each patient were retrospectively reviewed to evaluate the effect of the following factors on the success of the procedure: distance from the lesion to the localizing wire, breast density, breast size, specimen volume, and lesion volume. All radiographs were independently evaluated by two radiologists who are experts in breast imaging. RESULTS: Needle-localized breast biopsy was successful in 254 (93.3%) of 272 lesions. Placement of the localization wire within 5 mm of the breast lesion was a significant predictor of successful lesion removal (P = .007). Results from logistic regression analysis showed that needle-localized breast biopsy failure was associated with increased wire distance (P = .0006), decreased breast size (P = .02), and decreased specimen volume (P = .03). CONCLUSION: Needle localization wires should be placed within 5 mm of mammographically visible lesions to increase the probability of successful lesion excision.     

Hepatic cavernous hemangioma: temporal peritumoral enhancement during multiphase dynamic MR imaging

PURPOSE: To determine whether temporal parenchymal enhancement around hepatic cavernous hemangiomas can be correlated with the rapidity of intratumoral contrast material enhancement and/or tumor volume at dynamic magnetic resonance (MR) imaging. MATERIALS AND METHODS: Dynamic MR images obtained in 94 patients with 167 hemangiomas were retrospectively reviewed for peritumoral enhancement. Tumor volume was estimated by using the longest dimension on nonenhanced images. Speed of intratumoral contrast material enhancement was determined with early nonequilibrium phase images and was categorized as rapid (>75% of tumor volume), intermediate (25%-75% of tumor volume), or slow (<25% of tumor volume). RESULTS: Thirty-two of the 167 hemangiomas (19%) had temporal peritumoral enhancement, which was more common in hemangiomas with rapid enhancement (20 of 49 [41%]) than in those with intermediate (12 of 62 [19%]) and slow (0 of 56 [0%]) enhancement (P: <.001). The mean diameter of the hemangiomas with peritumoral enhancement was not significantly different from that of hemangiomas without peritumoral enhancement (P: >.05). Hemangiomas with rapid enhancement (mean diameter, 16 mm +/- 8), however, were significantly smaller than those with intermediate enhancement (mean diameter, 33 mm +/- 34) (P: <.001). CONCLUSION: Temporal peritumoral enhancement on dynamic MR images of hepatic hemangiomas correlates well with the speed of intratumoral contrast material enhancement and was most commonly encountered in rapidly enhancing small lesions. There was no statistically significant relationship, however, between peritumoral enhancement and tumor volume.     

Combined perfusion- and diffusion-weighted MR imaging in acute ischemic stroke during the 1st week: a longitudinal study

PURPOSE: To compare findings with different magnetic resonance (MR) perfusion maps in acute ischemic stroke. MATERIALS AND METHODS: Combined diffusion-weighted (DW) and perfusion-weighted (PW) MR imaging was performed in 49 patients with acute (<24 hours) stroke, on the 1st and 2nd days and 1 week after stroke. Volumes of hypoperfused tissue on maps of relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), and mean transit time (MTT) were compared with the volume of infarcted tissue at DW imaging. RESULTS: The mean infarct volume increased from 41 to 65 cm(3) between the 1st and 2nd days (P: <.001; n = 49). On the 1st day, all perfusion maps on average showed hypoperfusion lesions larger than the infarct at DW imaging (P: <.001; n = 49). MTT maps showed significantly (P: <.001) larger hypoperfusion lesions than did rCBF maps, which showed significantly (P: <.001) larger hypoperfusion lesions than did rCBV maps. The sizes of the initial perfusion-diffusion mismatches correlated significantly with the extent of infarct growth (0.479 < r < 0.657; P: 相似文献   

Pleural disease in silicosis: pleural thickening, effusion, and invagination

PURPOSE: To retrospectively evaluate pleural disease on images from patients with autopsy-proved silicosis. MATERIALS AND METHODS: The study had institutional review board approval, and informed consent from relatives of diseased subjects was waived. Lung specimens were obtained at autopsy in 110 men (mean age, 72 years) who had been followed up radiologically for a mean of 14.8 years. Computed tomographic (CT) scans obtained within 2 years before death were examined for presence of pleural thickening; shape, composition, size, and subpleural location of progressive massive fibrosis (PMF); and pleural invagination (bandlike structure between lesion and pleura). Lung specimens were reviewed and compared with CT findings. Serial chest radiographs and CT scans were reviewed for presence of pleural effusion. Association between radiographic findings and pleural invagination was analyzed with chi2 and Student t tests. Multiple logistic regression analysis was used to find predictive variables for pleural invagination. RESULTS: Pleural effusion was found in 12 (11%) patients at chest radiography and CT, and thickening was found in 64 (58%) patients at CT; the latter finding was significantly more frequent with complicated silicosis (P < .001). At CT, 128 PMF lesions were seen, 39 (30%) of which showed pleural invagination; CT scans showed pleural thickening in 36 (92%) of these 39 lesions. In 17 (44%) PMF lesions, CT scans depicted a bandlike structure that was pathologically confirmed to represent invaginated pleura in all cases. Pathologic presence of invagination was significantly associated with pleural thickening (P < .001), ipsilateral pleural effusion (P < .01), interstitial fibrosis (P < .05), and the nearness of PMF to the pleura (P < .005). Multiple logistic regression analysis showed that pleural thickening (odds ratio, 62.51; 95% confidence interval [CI]: 5.564, 70.2) and pleural effusion (odds ratio, 25.865; 95% CI: 1.992, 335.8) were significant CT variables associated with presence of pathologic pleural invagination (P = .001 and .013, respectively). Five PMF lesions had radiographic features of rounded atelectasis. CONCLUSION: Various pleural abnormalities can occur in silicosis, especially in advanced disease.     

Hypoxic-ischemic brain injury in the neonatal rat model: relationship between lesion size at early MR imaging and irreversible infarction

BACKGROUND AND PURPOSE: By using a neonatal rat hypoxia-ischemia (HI) model, we studied the relationship between lesion volume-measured by diffusion-weighted imaging (DWI) and T2-weighted imaging (T2WI) at an early time point-and irreversible infarct volume. We also evaluated the optimal apparent diffusion coefficient (ADC) threshold that provides the best correlation with irreversible infarct size. MATERIALS AND METHODS: Twenty-three neonatal rats underwent right common carotid artery ligation and hypoxia. MR imaging was performed 1-2 hours post-HI by using DWI and T2WI and at day 4 post-HI by using T2WI. Lesion volumes relative to whole brain (%LV) were measured on ADC maps by using different relative ADC thresholds 60%-80% of mean contralateral ADC and T2WI. Pearson correlation and multiple linear regression analysis were used to study the relationships between ln(%LV) at MR imaging and %LV at histopathology. RESULTS: At 1-2 hours post-HI, all lesion volume measurements on DWI were significantly correlated with the infarct volume on histopathology, with the best correlation attained at the 80% ADC threshold (r = 0.738; P < .001). The estimated regression formula was %LV on histopathology = 20.60 + 3.33 ln(%LV on 80% ADC threshold) (adjusted R(2) = 0.523; P < .001). Lesion volume at 1-2 hours post-HI tended to underestimate the final infarct volume. CONCLUSION: Early post-HI MR imaging by using DWI correlates moderately well with the size of irreversible infarct, especially when measured by using a relative ADC threshold of 80% mean contralateral ADC.     

Renal fibrosis: prediction from acute pyelonephritis focus volume measured at 99mTc dimercaptosuccinic acid SPECT.

PURPOSE: To evaluate whether acute pyelonephritis lesion volume derived from acute technetium 99m ((99m)Tc) dimercaptosuccinic acid (DMSA) renal single photon emission computed tomographic (SPECT) images is predictive of the development of subsequent renal fibrosis. MATERIALS AND METHODS: Children with acute pyelonephritis underwent (99m)Tc DMSA renal SPECT during acute infection and 6-10 months later. At quantitative analysis, the volume of photopenic lesions and the ratio of radioactivity in the photopenic lesion to that in normal renal tissue were calculated. Sensitivity, specificity, and positive and negative predictive values were determined. RESULTS: Sixty-nine acute pyelonephritis foci in 44 children were analyzed. Thirty-seven (54%) of these lesions were normal on follow-up renal scans, while 32 (46%) developed scars. Significant differences in the photopenic lesion volume were found between the two groups (P < .001). When photopenic lesion volume indicated a positive diagnosis (>or=4.6-cm(3) lesion volume), sensitivity, specificity, positive predictive, and negative predictive values were 96.7%, 92.3%, 90.6%, and 97.3%, respectively. CONCLUSION: Quantitative analysis of acute DMSA renal SPECT findings is valuable in predicting renal fibrosis. The volume of an acute pyelonephritis lesion is useful in predicting the development of fibrosis.     

Angiography of primary central nervous system angiitis of childhood: conventional angiography versus magnetic resonance angiography at presentation

BACKGROUND AND PURPOSE: To systematically analyze conventional angiographic (CA) features of children with primary central nervous system angiitis (cPACNS), to compare and correlate CA and MR angiography (MRA) lesion characteristics, and to define the sensitivity and specificity of MRA with CA as a reference standard. METHODS: A retrospective, single-center cohort study of consecutive patients with cPACNS was performed. Patients with CA and MRA studies at diagnosis were included. Imaging studies were blindly reviewed by 2 neuroradiologists using a standard analysis protocol. CA and MRA studies were compared using nonparametric analysis. RESULTS: Of 45 patients with MRA at diagnosis, there were 25 for whom CA and MRA studies were performed within 1 month of each other. These comprised the study group. The CA distribution of lesions was multifocal (76%) and proximal (86%) (P < .05) with a trend toward unilaterality (P = .06) with anterior circulation involvement (P = .08). The sensitivity and specificity of MRA for CA abnormality was 70% and 98%, respectively. There was no significant difference between MRA and CA for lesion detection or characterization (P = .87), and the modalities showed a fair correlation (kappa = 0.4). CONCLUSION: Angiographic lesions are multifocal and occur proximally and unilaterally within the anterior circulation. There is no significant difference in the ability of MRA to detect and characterize lesions when compared with CA.     

MR imaging of hepatocellular carcinoma: relationship between lesion size and imaging findings, including signal intensity and dynamic enhancement patterns

PURPOSE: To assess the relationship between lesion size and MR imaging findings of pathologically-proven hepatocellular carcinoma (HCC). MATERIALS AND METHODS: In a retrospective, single-center study, 37 consecutive patients were identified between 1999 and 2005 that underwent preoperative MRI and surgical resection of HCC. A total of 47 lesions (mean size = 6.85 cm, range = 1-25 cm) were assessed for signal intensity (SI), enhancement patterns, and secondary morphologic features. Interobserver rating, percentage enhancement, and contrast-to-noise-ratio (CNR) were determined. Lesions were assessed for combinations of typical MRI features. Regression analysis was used to assess relations between MRI findings and tumor size. RESULTS: On fat-suppressed T2-weighted (T2w) fast-spin-echo, smaller lesions had lower SI compared to larger lesions (P < 0.05). In the arterial phase, smaller lesions showed significantly higher percentage enhancement compared to larger lesions (P < 0.05). In the delayed phase, smaller lesions showed less pronounced washout (P < 0.05). Heterogeneity of the lesions, including fatty infiltration, internal nodules, or mosaic pattern, was observed significantly more frequently in larger lesions (P < 0.001). The classic combination of high T2w signal, strong arterial enhancement, and delayed phase washout was present in 23 of 44 lesions (52%). CONCLUSION: Smaller HCC often showed lower SI on T2w, more intense arterial enhancement, and less pronounced delayed washout compared to larger HCC.     

Do different types of liver lesions differ in their uptake of the microbubble contrast agent SH U 508A in the late liver phase? Early experience

PURPOSE: To compare the uptake of SH U 508A in different types of liver lesions by using stimulated acoustic emission. MATERIALS AND METHODS: Thirty-seven patients with characterized lesions (metastasis, n = 17; hepatocellular carcinoma, n = 4; hemangioma, n = 9; focal nodular hyperplasia, n = 7) received 2.5 g SH U 508A. After 5 minutes, stimulated acoustic emission was elicited by using a previously described method. Liver and/or lesional differences were assessed with videodensitometry (objective conspicuity score), and two observers assessed each lesion by using a six-point scale (subjective conspicuity score). RESULTS: Metastases and hepatocellular carcinoma had low stimulated acoustic emission; median objective conspicuity scores were 70% and 68% (all scores were > or =43%), respectively, and subjective conspicuity scores were 2 or higher for both observers. Hemangiomas had reduced stimulated acoustic emission, with more variability; the median objective conspicuity score was 41% (range, 9%-72%), and the median subjective conspicuity scores were 2 (range, 1-4) and 3.5 (range, 1-5) for observers 1 and 2, respectively. Focal nodular hyperplasia had stimulated acoustic emission comparable to that of the liver in all cases; the median objective conspicuity score was -4.7% (all scores were <6%), and the subjective conspicuity score was 1 or lower for both observers. This finding completely separated focal nodular hyperplasia and malignancies. Significant differences were seen between focal nodular hyperplasia and all other lesion types (P < .05). CONCLUSION: Strong late-phase lesional uptake of SH U 508A is characteristic of focal nodular hyperplasia, is seen in some hemangiomas, and was not observed in malignancies.     

Breast lesion detection and characterization at contrast-enhanced MR mammography: gadobenate dimeglumine versus gadopentetate dimeglumine

PURPOSE: To prospectively and intraindividually compare equivalent (0.1 mmol per kilogram of body weight) doses of gadobenate dimeglumine and gadopentetate dimeglumine for accuracy of detection and characterization of breast lesions at contrast material-enhanced magnetic resonance (MR) mammography. MATERIALS AND METHODS: Ethics committee approval and informed consent were obtained. Twenty-six consecutive women (mean age, 47.8 years) suspected of having a breast tumor at mammography and sonography underwent two identical MR examinations at 1.5 T; examinations were separated by more than 48 hours but less than 72 hours. A T1-weighted three-dimensional gradient-echo sequence was used, and images were acquired before and at 0, 2, 4, 6, and 8 minutes after randomized injection of gadopentetate dimeglumine or gadobenate dimeglumine at an identical flow rate of 2 mL/sec. Separate and combined assessment of unenhanced, contrast-enhanced, and subtracted images was performed blindly by two readers in consensus. Accuracy for lesion detection was determined against a final diagnosis based on findings at conventional mammography, sonography, and surgery. Sensitivity, specificity, positive and negative predictive values, and overall accuracy for malignant lesion identification were determined against histologic results. Data were analyzed with the McNemar test, proportional odds models, and analysis of variance. RESULTS: MR mammography with gadobenate dimeglumine depicted significantly (P = .003) more lesions (45 of 46) than did that with gadopentetate dimeglumine (36 of 46), and detected lesions were significantly (P < .001) more conspicuous with gadobenate dimeglumine. Confidence for characterization was significantly (P = .031) greater with gadobenate dimeglumine. Comparison of the contrast agents for their ability to help identify malignant lesions revealed significant (P = .02) superiority for gadobenate dimeglumine: Sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy for malignant lesion identification were, respectively, 94.7%, 100%, 100%, 80.0%, and 95.6% with gadobenate dimeglumine and 76.3%, 100%, 100%, 47.1%, and 80.4% with gadopentetate dimeglumine. Quantitative evaluation of signal intensity-time curves revealed significantly (P < .001) greater lesion enhancement with gadobenate dimeglumine. CONCLUSION: Detection of breast lesions and accurate identification of malignant lesions at MR imaging are significantly superior with gadobenate dimeglumine in comparison with gadopentetate dimeglumine.     

人工智能定量测量对新型冠状病毒肺炎患者胸部CT炎性病灶动态变化的评估价值

目的探讨人工智能(AI)辅助定量测量评估新型冠状病毒肺炎(COVID-19)胸部CT动态变化的价值。方法回顾性分析2020年1月15日至3月10日在华中科技大学同济医学院附属武汉市中心医院接受治疗的99例确诊COVID-19患者的临床和胸部CT动态影像资料。依据最终诊断,99例患者分为普通型(36例)、重型(33例)和危重型(30例),分析3型间CT影像学表现,包括CT基本征象、肺炎病灶总体积及肺炎病灶总体积占全肺体积的百分比(体积比)。使用AI软件定量评价胸部CT影像的动态变化,定量指标有CT病灶峰值时间、病灶峰值总体积、病灶峰值体积比、总体积最大增长率、体积比最大增长率。采用Kruskal-Wallis秩和检验比较3型间定量指标的差异,以χ2检验或Fisher确切概率法比较3型间定性指标的差异。采用序列测量及散点图显示3型COVID-19病灶体积比的演变趋势,采用ROC曲线分析肺炎病灶体积比及其最大增长率预判普通型肺炎转为重型或危重型的价值。结果普通型、重型、危重型COVID-19患者年龄及性别分布差异有统计学意义(P<0.05),其中重型与危重型患者年龄显著高于普通型(P<0.01)。与普通型[2.5(1.0,5.0)d]和危重型[2.5(1.0,4.0)d]相比,重型发病至首次胸部CT扫描的时间延长[5.0(2.5,8.0)d,P<0.01]。普通型、重型、危重型COVID-19患者首诊肺部多叶受累的差异有统计学意义(分别为20例、29例、25例,χ2=10.403,P=0.006),其中重型和危重型患者多肺叶受累发生率显著高于普通型(P=0.002)。普通型、重型、危重型COVID-19患者首诊体积比差异有统计学意义[分别为1.0%(0.2%,4.7%)、9.30%(1.63%,26.83%)、2.10%(0.64%,8.61%),Z=14.236,P=0.001],其中重型患者体积比显著高于普通型(P<0.001),普通型与危重型差异无统计学意义(P=0.062)。随访CT显示肺炎病灶呈进展及恢复的动态转变,可见多期相病灶共存。3型COVID-19患者病灶体积比散点图中趋势线显示进展期病灶均呈由少到多的发展。普通型、重型及危重型病灶峰值体积比分别为9.75%(4.83%,13.18%)、29.80%(23.99%,42.36%)和61.81%(43.73%,72.82%),差异有统计学意义(Z=74.147,P<0.001),病灶体积比的最大增长率分别为1.27%(0.50%,1.81%)/d、4.39%(3.16%,5.54%)/d和6.02%(4.77%,9.96%)/d,差异有统计学意义(Z=52.453,P<0.001),病灶峰值时间分别为12.0(9.0,15.0)d、13.0(10.0,16.0)d和16.5(12.0,25.0)d,差异有统计学意义(Z=9.524,P=0.009)。以肺炎病灶峰值体积比22.60%、体积比的最大增长率1.875%/d为界值,诊断普通型转重型或危重型的灵敏度分别为92.10%、96.83%,特异度分别为100%、80.56%,曲线下面积分别为0.987、0.925。结论COVID-19肺炎病灶在CT上呈类抛物线样变化,采用AI技术对CT肺炎病灶体积比进行动态精确测量有助于评价疾病的严重程度和预判疾病的发展趋势,病灶体积比快速增长的患者更容易转变为重型或危重型。     

Arterial and venous smooth muscle cell proliferation in response to co-culture with arterial and venous endothelial cells.

PURPOSE: To determine whether definable differences exist between arterial and venous smooth muscle cells (SMCs), as measured by proliferative response to co-culture with arterial or venous endothelial cells (ECs). MATERIALS AND METHODS: Human aortic ECs (A-ECs) and saphenous vein ECs (V-ECs) were cultured opposite either aortic SMCs (A-SMCs) or saphenous vein SMCs (V-SMCs). At selected time intervals, SMCs were counted by fluorescence microscopy. RESULTS: In the presence of an intact EC monolayer, A-ECs induced a 9%-31% increase in A-SMC (P < or = .001) and a 15%-37% increase in V-SMC (P < or = .001) proliferation. Saphenous vein ECs induced a 50%-71% increase in A-SMC (P < or = .001) and a 40%-62% increase in V-SMC (P < or = .001) proliferation. The small proliferative difference between A-SMCs and V-SMCs was significant for co-culture with A-ECs (P < or = .001) and V-ECs (P < or = .001). Of note, compared to A-ECs, V-ECs induced a significantly greater A-SMC (P < or = .001) and V-SMC (P < or = .001) proliferative response. CONCLUSION: A small, but definable, difference exists between A-SMCs and V-SMCs, as measured by proliferative response in co-culture with A-ECs and V-ECs.     

Percutaneous MR imaging-guided radiofrequency interstitial thermal ablation of tongue base in porcine models: implications for obstructive sleep apnea syndrome

PURPOSE: To test the feasibility and safety of a percutaneous magnetic resonance (MR) imaging-guided technique for radiofrequency (RF) interstitial thermal ablation of the tongue base and to correlate MR appearance of induced thermal lesions with histopathologic findings in pigs in acute and chronic porcine models. MATERIALS AND METHODS: A 1-cm-tip RF electrode was inserted percutaneously into the tongue in 10 pigs with 0.2-T real-time MR guidance. The RF electrode was advanced up the midline between lingual arteries and stopped short of tongue mucosa. RF interstitial thermal ablation was performed at 90 degrees C +/- 2 and lasted 10 minutes. Postablation images were obtained with a 1.5-T MR imager. Five pigs were sacrificed immediately (acute model), while five were followed up for 1 month (chronic model) before they were sacrificed. MR-compatible fiducial coils were inserted into tongues with MR imaging guidance prior to RF ablation in the chronic group. Tongues were harvested for histopathologic analysis. Mean thermal lesion volume was compared with the Student t test on images obtained immediately, 2 weeks, and 1 month after RF ablation. Interclass correlation coefficients of lesion diameters at gross pathologic analysis and corresponding diameters with each pulse sequence were calculated. RESULTS: Successful MR imaging-guided electrode positioning was achieved in all procedures without intra- or postprocedure complications because there was high vascular conspicuity and tissue contrast. Thermal lesions appeared hypointense with hyperintense surrounding rims with all sequences in both groups. At pathologic analysis, acute lesions appeared as pale necrotic areas surrounded by hyperemic rims, while chronic lesions demonstrated progressive circumferential fibrosis and significant volume shrinkage (P <.01). Thermal lesion diameters measured at gross pathologic analysis best agreed with corresponding diameters measured on short inversion time inversion-recovery images (interclass correlation coefficient = 0.85). CONCLUSION: The results of this investigation demonstrate MR imaging-guided RF interstitial thermal ablation of the tongue base is feasible and safe and illustrate imaging and pathologic phenomena associated with creation and evolution of the induced thermal lesions.