Reliability of acoustic radiation force impulse shear wave elastography in the evaluation of liver stiffness in morbidly obese patients.

PURPOSE: To evaluate technical and patient-related factors that can affect the reliability of acoustic radiation force impulse shear wave elastography (ARFI-SWE) in morbidly obese patients. METHODS: A prospective single-center study was performed on 41 patients (32 females, 78%) presenting for preoperative evaluation for bariatric surgery. ARFI-SWE was performed using a 6 to 1.5 MHz curved (6C1) transducer. Hepatic steatosis was mild, moderate, severe, and absent in 24.4%, 12.2%, 43.9%, and 19.5% of patients, respectively. Interquartile range/median (IQR/M) ranged from 0.05 to 2.07 (0.78 ± 0.56 m/s). Twenty patients (48.7%) had reliable measurements (IQR/M < 0.3). Shear wave velocity (SWV) values were >1.34 m/s (clinically significant fibrosis) in 25 of 41 patients (61%) and >2.2 m/s (advanced fibrosis) in 19 patients (46%). RESULTS: Median SWV was correlated with body mass index (BMI; correlation coefficient [CC] = .37; 95% CI, 0.07-0.61; P-value = .03) and skin-to-liver capsule distance (SLD) (CC = .38; 95% CI, 0.09-0.62; P-value = .01). IQR/M was higher in patients with BMI > 40 (0.24 ± 0.11 vs 0.39 ± 0.25, P-value = .031) and SLD > 3 cm (0.46 ± 0.27 vs 0.23 ± 0.08, P-value = .001), and there was higher number of unreliable examinations among patient with SLD > 3 cm (16/23 vs 5/18, P-value = .01). CONCLUSION: ARFI-SWE is technically more challenging among patients with higher BMI and SLD, resulting in a higher number of unreliable studies, which highlights the need for further advancement of ARFI technology.

Predictive Value of Abnormal Findings on Covered Transjugular Intrahepatic Portosystemic Shunt Baseline Doppler Sonography.

Doppler ultrasound (DUS) is frequently performed as a screening and diagnostic modality to evaluate the transjugular intrahepatic portosystemic shunt (TIPS) for short- and intermediate-term complications of the procedure. However, the clinical significance of initial frequently observed abnormalities in flow velocities, gradient, and direction in patients with covered TIPS is less studied. A retrospective study was performed between January 2005 and December 2014, and all patients undergoing covered TIPS procedure for the management of portal hypertension were included. Abnormal DUS findings were defined as intrashunt peak systolic velocities (PSVs) less than 90 or greater than 190 cm/s, intrashunt gradient greater than 50 cm/s, and abnormal flow direction in the main, right, and/or left portal veins. A total of 283 patients with adequate clinical follow-up and baseline TIPS DUS were included in the study. Median follow-up was 18.2 months. During the follow-up period, portal hypertension symptoms recurred in 83 patients who underwent TIPS angiography and/or revision. Of the 83, 57 had an elevated portosystemic gradient (>12 mm Hg) requiring angioplasty/stenting. With regard to baseline ultrasound, low PSVs were present in 88 patients (31.1%), high PSVs in 44 patients (15.5%), and elevated gradient in 98 patients (34.6%). The rate of developing TIPS stenosis in the future was not higher in patients with abnormal DUS parameters. For example, 26 (19.7%) of 132 patients with abnormal TIPS velocities developed stenosis compared with 31 (20.5%) of 151 patients with normal velocities (P = 0.9). Based on these results, abnormal DUS findings observed on baseline TIPS ultrasound examination have low predictive value for future covered TIPS dysfunction and failure.

18F-FDG Is a Superior Indicator of Cognitive Performance Compared to 18F-Florbetapir in Alzheimer's Disease and Mild Cognitive Impairment Evaluation: A Global Quantitative Analysis.

BACKGROUND: 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) and 18F-florbetapir PET are approved neuroimaging biomarkers for the Alzheimer's disease (AD) and mild cognitive impairment (MCI). OBJECTIVES: This study aims to compare the efficacy of 18F-FDG and 18F-florbetapir PET at evaluating the cognitive performance of patients with AD, MCI, and normal controls (NC). METHODS: 63 subjects (36 male/27 female, mean age = 68.3) including 19 AD, 23 MCI, and 21 NC underwent 18F-FDG and 18F-florbetapir PET imaging. A global quantification approach was applied on supra-tentorial, frontal, parieto-occipital, temporal, and cerebellar brain regions by calculating the global SUVmean ratios (GSUVr) as the weighted average of all regional SUVmean. 18F-FDG and 18F-florbetapir GSUVr of each region were subsequently correlated with the Mini-Mental State Examination (MMSE). RESULTS: Subjects were studied in five categories as NC, MCI patients, AD patients, MCI and AD patients grouped together (MCI/AD), and a group including all the subjects (NC/MCI/AD). Both 18F-FDG and 18F-florbetapir could successfully detect subjects with dementia (p < 0.001). Studied in all regions and groups, the correlation analysis of 18F-FDG GSUVr with MMSE scores was significant in more regions and groups compared to that of 18F-florbetapir. We also demonstrated that the correlation of 18F-FDG GSUVr with MMSE is stronger than that of 18F-florbetapir in the supra-tentorial and temporal regions. CONCLUSIONS: This study reveals how 18F-FDG-PET global quantification is a superior indicator of cognitive performance in AD and MCI patients compared to 18F-florbetapir PET. Accordingly, we still recommend 18F-FDG-PET over amyloid imaging in the evaluation for AD and MCI.

Association of Complete Radiologic and Pathologic Response following Locoregional Therapy before Liver Transplantation with Long-Term Outcomes of Hepatocellular Carcinoma: A Retrospective Study.

PURPOSE: To evaluate long-term outcomes of patients with hepatocellular carcinoma (HCC) who show a complete response (CR) vs non-CR on pretransplantation imaging studies or pathologic evaluation of liver explants after locoregional therapy (LRT) before liver transplantation. MATERIALS AND METHODS: Patients listed for liver transplantation for HCC (March 1998 to December 2010) undergoing LRT with available multiphase MR/CT imaging before transplantation were included. Pathologic response was evaluated based on liver explant pathology. A total of 108 patients (17 women; 16%) met the inclusion criteria. RESULTS: Radiologic CR was achieved in 65 patients (60%) vs non-CR in 43 (40%), and pathologic CR was achieved in 36 patients (33%) vs non-CR in 72 (67%). Mean 5-year overall survival (OS) from the time of listing and recurrence-free survival (RFS) after liver transplantation were significantly better for patients with pathologic CR vs non-CR on explant pathology (OS, 83.3% vs 65.2% [28% difference; P = .046]; RFS, 80.6% vs 62.5% [29% difference; P = .045]). Mean 5-y OS and RFS were not significantly different between patients with radiologic CR or non-CR on pretransplantation imaging (OS, 75.4% vs 65.1% [P = .12]; RFS, 74% vs 62.8% [P = .17]). CONCLUSIONS: Achievement of a pathologic CR vs non-CR in response to LRT before liver transplantation for HCC is associated with improved OS from time of listing and improved RFS after liver transplantation. However, current imaging paradigms fall short of accurate delineation of response to LRT, resulting in poor correlation of outcomes between pathologic and radiologic CR.

The Evolving Role of FDG-PET/CT in the Diagnosis, Staging, and Treatment of Breast Cancer.

The applications of 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/X-ray computed tomography (PET/CT) in the management of patients with breast cancer have been extensively studied. According to these studies, PET/CT is not routinely performed for the diagnosis of primary breast cancer, although PET/CT in specific subtypes of breast cancer correlates with histopathologic features of the primary tumor. PET/CT can detect metastases to mediastinal, axial, and internal mammary nodes, but it cannot replace the sentinel node biopsy. In detection of distant metastases, this imaging tool may have a better accuracy in detecting lytic bone metastases compared to bone scintigraphy. Thus, PET/CT is recommended when advanced-stage disease is suspected, and conventional modalities are inconclusive. Also, PET/CT has a high sensitivity and specificity to detect loco-regional recurrence and is recommended in asymptomatic patients with rising tumor markers. Numerous studies support the future role of PET/CT in prediction of response to neoadjuvant chemotherapy (NAC). PET/CT has a higher diagnostic value for prognostic risk stratification in comparison with conventional modalities. With the continuing research on the treatment planning and evaluation of patients with breast cancer, the role of PET/CT can be further extended.

Pre-treatment partial-volume-corrected TLG is the best predictor of overall survival in patients with relapsing/refractory non-hodgkin lymphoma following radioimmunotherapy.

The role of fluorodeoxyglucose-positron emission tomography (FDG-PET) has been well established in assessment of lymphoma, including non-Hodgkin lymphoma (NHL). The aim of this study was to compare changes and survival predictive values of various quantification parameters of FDG-PET/CT in patients with relapsing/refractory lymphoma before and after radioimmunotherapy (RIT). Data from 17 patients with relapsing/refractory NHL, treated with targeted RIT after chemotherapy/radiotherapy, were retrospectively collected. FDG-PET/CT scans were performed approximately three months before and six months after RIT. An adaptive contrast-oriented thresholding algorithm was used to segment lesions on the FDG-PET images. Wilcoxon signed-rank tests were used to assess changes in SUVmax, SUVmean, partial volume-corrected SUVmean (pvcSUVmean), total lesion glycolysis (TLG), and pvcTLG before and after treatment. The patients were followed up after completing RIT for up to 10 years. Kaplan-Meier and Cox regression analyses evaluated the association between the quantification parameters and survival data. In the survived group, the decrease in mean percentage of change for TLG and pvcTLG was greater than SUVmax, SUVmean and pvcSUVmean [TLG: 253.9 to 106.9, -81.4%; P = 0.052 and pvcTLG: 368.9 to 153.3, -58.4%; P = 0.04]. In addition, overall survival (OS) was shorter in patients with pre-RIT pvcTLG more than 644 compared to those below this value (log-rank P < 0.01). In univariate Cox regression for OS, a higher baseline pvcTLG was a significant prognostic factor (HR: 6.8, P = 0.02). Our results showed that pre-treatment pvcTLG was the best predictor of OS in patients with relapsing/refractory NHL following RIT.

Update of the role of PET/CT and PET/MRI in the management of patients with cervical cancer.

In cervical cancer (CC), fluorine18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) has been proven to be beneficial for patient management. Positron emission tomography/CT is useful in pretreatment evaluation due to the ability to evaluate disease extent and to assess regional lymph nodes as well as distant sites for metastases. Positron emission tomography/CT has an impact on treatment planning as well as it is incorporated in radiation therapy planning, resulting in more appropriate and effective treatment with less cost and radiation dose to normal tissues. Positron emission tomography/CT is used to predict early treatment response and to assess treatment response after completion of concurrent chemoradiation therapy. Positron emission tomography/CT has been used for surveillance after treatment as well as for restaging in suspected recurrent or metastatic disease. Qualitative PET/CT imaging findings as well as quantitative parameters such as maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) are useful to predict prognosis and clinical outcome. Moreover, PET imaging using other radiotracers to detect and quantify hypoxia may help to identify aggressive tumors and predict treatment outcome even though it is not widely clinical used. Positron emission tomography/magnetic resonance imaging (PET/MRI) instruments are now available, which may potentially improve evaluation of primary tumors and metastatic sites given the improved soft tissue contrast resolution of MRI relative to CT. This article reviews the role of 18F-FDG PET/CT, hypoxia agent PET/CT, and 18F-FDG PET/MRI in the management of patients with CC.