Shuixing Zhang

Intravoxel incoherent motion (IVIM) in evaluation of breast lesions: Comparison with conventional DWI

OBJECTIVES To obtain perfusion as well as diffusion information in normal breast tissues and breast lesions from intravoxel incoherent motion (IVIM) imaging with biexponential analysis of multiple b-value diffusion-weighted imaging (DWI) and compare these parameters to apparent diffusion coefficient (ADC) obtained with monoexponential analysis in their ability to discriminate benign lesions and malignant tumors. MATERIALS AND METHODS In this prospective study, informed consent was acquired from all patients. Eighty-four patients with 40 malignant tumors, 41 benign lesions, 30 simple cysts and 39 normal breast tissues were imaged at 1.5 T utilizing contrast-enhanced magnetic resonance imaging (MRI) and DWI using 12 b values (range: 0-1000 s/mm(2)). Tissue diffusivity (D), perfusion fraction (f) and pseudo-diffusion coefficient (D*) were calculated using segmented biexponential analysis. ADC (b = 0 and 1000 s/mm(2)) was calculated with monoexponential fitting of the DWI data. D, f, D* and ADC values were obtained for normal breast tissues, simple cysts, benign lesions and malignant tumors. Receiver operating characteristic analysis was performed for all DWI parameters. RESULTS There was good interobserver agreement on the measurements between the 2 observers. D values were significantly different among malignant tumors, benign lesions, simple cysts and normal breast tissues (P = 0.000) and it was the same result for f, D* and ADC values. Further comparisons of these 4 parameters between every single pair were as the following. D and ADC values of malignant tumors were significantly smaller than those of benign lesions, simple cysts and normal tissues (P = 0.000, respectively). The f value of malignant tumors was significantly higher than that of benign lesions, simple cysts and normal breast tissues (P = 0.001, P = 0.000, and P = 0.000). D and ADC values demonstrated higher sensitivity and specificity in differentiating benign lesions and malignant tumors, with area under the curve (AUC) of 0.952 and 0.945, respectively, while f and D* with the lower AUC of 0.723 and 0.630, respectively. Combining f and D values had a sensitivity up to 98.75%. CONCLUSION DWI response curves in malignant tumors, benign lesions and normal fibroglandular tissues are found to be biexponential fit in comparison with the monoexponential fit for simple cysts. IVIM provides separate quantitative measurement of D for cellularity and f and D* for vascularity and is helpful for differentiation between benign and malignant breast lesions.

The efficacy of sodium bicarbonate in preventing contrast-induced nephropathy in patients with pre-existing renal insufficiency: a meta-analysis

Objective The aim of this meta-analysis was to explore the efficacy of sodium bicarbonate in preventing contrast-induced nephropathy (CIN). Methods We searched PubMed, Medline and the Cochrane Library from 1 January 2004 to 1 August 2014. The effect estimate was expressed as a pooled OR with 95% CI, using the fixed-effects or random-effects model. Results 20 randomised controlled trials (n=4280) were identified. Hydration with sodium bicarbonate was associated with a significant decrease in CIN among patients with pre-existing renal insufficiency (OR 0.67, 95% CI 0.47 to 0.96; p=0.027). However, moderate heterogeneity was noted across trials (I2=48%; p=0.008). Subgroup analyses indicated a better effect of sodium bicarbonate in studies using low-osmolar (OR 0.59, 95% CI 0.37 to 0.93; p=0.024) compared with iso-osmolar contrast agents (OR 0.76, 95% CI 0.43 to 1.34; p=0.351). The odds of CIN with sodium bicarbonate were lower in studies including only patients undergoing emergency (OR 0.16, 95% CI 0.05 to 0.51; p=0.002) compared with elective procedures (OR 0.76, 95% CI 0.54 to 1.06; p=0.105). Sodium bicarbonate was more beneficial in patients given a bolus injection before procedures (OR 0.15, 95% CI 0.04 to 0.54; p=0.004) compared with continuous infusion (OR 0.75, 95% CI 0.53 to 1.05; p=0.091). Sodium bicarbonate plus N-acetylcysteine (OR 0.17, 95% CI 0.04 to 0.79; p=0.024) was better than sodium bicarbonate alone (OR 0.71, 95% CI 0.48 to 1.03; p=0.071). The effect of sodium bicarbonate was considered greater in papers published before (OR 0.19, 95% CI 0.09 to 0.41; p=0.000) compared with after 2008 (OR 0.85, 95% CI 0.62 to 1.16; p=0.302). However, no significant differences were found in mortality (OR 0.69, 95% CI 0.36 to 1.32; p=0.263) or requirement for dialysis (OR 1.08, 95% CI 0.52 to 2.25; p=0.841). Conclusions Sodium bicarbonate is effective in preventing CIN among patients with pre-existing renal insufficiency. However, it fails to lower the risks of dialysis and mortality and therefore cannot improve the clinical prognosis of patients with CIN.

Celecoxib Enhances Radiosensitivity via Induction of G2-M Phase Arrest and Apoptosis in Nasopharyngeal Carcinoma

Background: Previous work has proposed that celecoxib may be able to enhance the effects of radiotherapy. However, the underlying mechanism of this activity has not yet been determined. Methods: The cell colony formation assay after the combination of celecoxib and radiation treatment was done on C666-1, CNE-1 and CNE-2 nasopharyngeal carcinoma cells, which expressed different COX-2 levels. Moreover, COX-2 knocked down or overexpressed cells were developed, and apoptosis and cell cycle analysis were performed. Results: Celecoxib enhances radiation cytotoxicity in C666-1 and CNE-1 nasopharyngeal carcinoma cells that expressed high COX-2 but not in CNE-2 cells that expressed low COX-2. The radiosensitization of celecoxib in C666-1 cells disappeared after the COX-2 knocked down, while the CNE-2 cells were radiosensitized by celecoxib after the transfection of COX-2. Moreover, celecoxib enhanced radiation-induced G2-M phase arrest was observed in some of the tested cells. Furthermore, we found that the radiosensitivity of celecoxib in nasopharyngeal carcinoma was correlated with the apoptosis induction. Additionally, the combination of celecoxib (25 mg/kg) and radiation (6 Gy) treatment significantly reduced tumor volume in C666-1 and CNE-2 nasopharyngeal carcinoma xenograft models. Conclusion: These results indicate that the combination of celecoxib and radiation treatment has potential application in radiotherapy, and these effects may be attributable to the G2-M cell phase arrest and enhancement of cell apoptosis.

An Updated Study to Determine Association between Gadolinium-Based Contrast Agents and Nephrogenic Systemic Fibrosis

Background Nephrogenic systemic fibrosis (NSF) is a rare but serious disorder disease affecting patients with advanced renal disease. Although multiple studies have indicated an association between gadolinium-based contrast agents (GBCAs) and NSF, some studies published after 2007 found no association. We therefore performed a meta-analysis to evaluate the association and analyze related (co)factors. Methods Studies for analysis were identified by searching PubMed, Embase, and the Cochrane Central Register of Controlled Trials through December 2014. Pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated using the fixed-effects model. Statistical heterogeneity was assessed by Q statistics and the I2 test. Publication bias was evaluated using Begg’s test, Egger’s test, funnel plot, and classic fail-safe N. Study quality was assessed using the Newcastle-Ottawa Scale. We also conducted sensitivity analyses, subgroup analyses and a cumulative meta-analysis. All statistical analyses were performed using Comprehensive Meta-Analysis 2.0. Results A total of 14 studies (6,398 patients) met the inclusion criteria, but 3 were excluded since they reported no NSF events. Meta-analysis of controlled trials indicated a significant association between GBCAs and NSF development (OR = 16.504; 95% CI: 7.455–36.533; P < 0.001) and between gadodiamide and NSF (OR = 20.037; 95% CI: 3.725–107.784; P < 0.001). No statistical heterogeneity was observed across studies (P = 0.819, I2 = 0%; P = 0.874, I2 = 0%, respectively). Cumulative analysis demonstrated that the pooled ORs for association between GBCAs and NSF decreased post-2007 compared to pre-2007 (OR = 26.708; 95% CI: 10.273–69.436; P<0.001). Conclusions Although this updated meta-analysis found a significant association between GBCAs and the incidence of NSF in patients with advanced renal disease, the association decreased after 2007. More studies, especially randomized controlled trials, are warranted to examine the potential association between GBCAs other than gadodiamide and NSF.

Safety and diagnostic image quality of iopromide: results of a large non-interventional observational study of European and Asian patients (IMAGE):

Background Iodine-based contrast agents such as iopromide play a central role in improving the diagnostic quality of imaging modalities using ionizing radiation. Purpose To investigate the safety and diagnostic image quality of iopromide in the routine clinical setting. Material and Methods This was an international, multicenter, prospective, single-arm, non-interventional study (NIS). The study was performed in out- and inpatients in 738 study centers in 21 countries in Europe and Asia. Iopromide was administered in a routine manner, in compliance with the local package insert. The use of premedication was at the discretion of the attending physician. Case report forms for 44,835 patients were analyzed (57.4% men). The median age of the patients was 55 years. Results For the vast majority of patients (94.8%), the contrast quality was rated as ‘good’ (55.8%) or ‘excellent’ (39.0%). For 1265 (2.8%) patients, there were reports of adverse drug reactions (ADRs) excluding tolerance indicators (TIs) (i.e. injection site warmth, feeling hot, or injection site pain of mild intensity). At least one ADR including TIs was reported in 2415 (5.4%) patients. There were 11 (0.02%) patients with serious ADRs, and no drug-related deaths. Events of injection site warmth and/or feeling hot were reported by 3.5%, nausea and/or vomiting by 0.96%, and urticaria, erythema, and/or rash by 0.54% of patients. Patients at risk for an acute idiosyncratic reaction (i.e. patients with a history of bronchial asthma, allergies, and/or contrast media reaction) had a higher incidence of ADRs compared with the overall study population. At-risk patients who did not receive premedication reported distinctly more ADRs compared with those who received premedication (12.0% versus 5.9%). Conclusion Iopromide was shown to be a well-tolerated contrast agent whose usage resulted in high image quality. No unknown ADRs were observed. Premedication with antiallergy drugs should be considered in at-risk patients.

Low-dose contrast-enhanced magnetic resonance imaging of brain metastases at 3.0T using high-relaxivity contrast agents

Background: Lesion-to-brain contrast after gadolinium administration is significantly higher at 3.0 Tesla (T) compared to 1.5T. The high in vivo relaxivity of gadobenate dimeglumine (Gd-BOPTA) may permit the use of lower-dose contrast agents. Purpose: To investigate whether low-dose contrast-enhanced MRI at 3.0T using a high-relaxivity contrast agent (Gd-BOPTA) can achieve a comparable or improved contrast-to-noise ratio (CNR) for the detection of brain metastases compared with examination of the same patient at 1.5T using a standard dose of gadopentetate dimeglumine (Gd-DTPA). Material and Methods: A total of 18 patients with known brain metastases were first imaged at 1.5T with 0.1 mmol/kg Gd-DTPA. Patients returned at least 24 hours later for imaging at 3.0T with Gd-BOPTA at cumulative doses of 0.025 mmol/kg, 0.05 mmol/kg, 0.075 mmol/kg, and 0.1 mmol/kg (0.1 mmol/kg body weight overall). The CNR of enhancing brain lesions compared to the normal contralateral white matter was calculated. For the 3.0T study using different cumulative doses of Gd-BOPTA, the CNR of lesions was compared with CNR of the same lesions imaged at 1.5T using 0.1 mmol/kg Gd-DTPA, by using the Wilcoxon matched-pairs signed-rank test. Results: At 1.5T with 0.1 mmol/kg Gd-DTPA, the mean CNR between enhanced lesions and cerebral white matter was 12.01 ± 2.53. With 3.0T imaging using different cumulative doses of Gd-BOPTA, the mean CNRs were 7.19 ± 4.06, 15.31 ± 6.37, 25.44 ± 11.02, and 31.88 ± 13.21. At 3.0T with 0.05 mmol/kg Gd-BOPTA, CNR was 1.34-fold higher compared to CNR at 1.5T with 0.1 mmol/kg Gd-DTPA (P <0.01). Conclusion: Comparable contrast enhancement of brain metastases can be achieved with a 0.05-mmol/kg dose of Gd-BOPTA at 3.0T compared to imaging at 1.5T using 0.1 mmol/kg Gd-DTPA.

Intravoxel incoherent motion MRI for the differentiation of benign, intermediate, and malignant solid soft-tissue tumors

To determine the diagnostic potential of apparent diffusion coefficient (ADC) and intravoxel incoherent motion (IVIM)‐derived parameters for the differentiation of benign, intermediate, and malignant solid soft‐tissue tumors.

Application value of MRI combined with positron emission tomography (PET)/CT in diagnosis and preoperative staging of tongue squamous cell carcinoma

This study aimed to compare and analyse the findings of tongue squamous cell carcinoma (TSCC) on MRI and positron emission tomography (PET)/CT and explore the diagnostic utility of combined MRI‐PET/CT in the diagnosis and preoperative staging of TSCC.

Diffusion-weighted multiparametric MRI for monitoring longitudinal changes of parameters in rabbit VX2 liver tumors.

To investigate the value of different quantitative models of diffusion‐weighted multiparametric imaging (DW‐MPI) including traditional as well as several advanced models for monitoring the longitudinal parameter changes in rabbit liver VX2 carcinoma and for correlating the perfusion‐related imaging parameters to vascularity of tumor tissue.

Significance of imaging and clinical features in the differentiation between primary and secondary pulmonary lymphoma

The aim of the present study was to analyze the differences in imaging and clinical features between primary pulmonary lymphoma (PPL) and secondary pulmonary lymphoma (SPL) to provide insight into pulmonary lymphoma for an improved clinical diagnosis. A retrospective study of 38 patients with pulmonary lymphoma (19 PPL and 19 SPL) treated between September 1, 2006, and December 31, 2015, was performed. The clinical manifestations, and computed tomography (CT) and positron emission tomography-CT images of each case were collected. χ2 and Fishers exact tests were applied to assess statistically significant differences between PPL and SPL in terms of clinical and imaging features. The significant variables were further applied to canonical discriminate analysis. The CT results revealed that the occurrence of a >3-cm mass (P=0.007), peripheral location (lower than the segmental bronchi) (P=0.027), cavitation (P=0.008) and consolidation (P=0.027) were associated with PPL, while peripheral and hilar location (P=0.003) or mediastinal and hilar lymph node engagement (P=0.044) were predominantly observed in SPL. However, no significant differences between clinical manifestations and the maximum standard uptake value of pulmonary lesions in PPL and SPL were identified (all P>0.05). A function derived from discriminate analysis was generated that may predict the affiliation to PPL or SPL radiographically, with an overall accuracy of ≤92.1%. The results of the present study revealed that PPL and SPL exhibit distinctive features on CT images due to distinct molecular mechanisms and growth patterns. Careful observation of CT features may be useful in the diagnosis of PPL and SPL regarding the tumor morphology, location and lymph node involvement.