pH-responsive ratiometric photoacoustic imaging of polyaniline nanoparticle-coated needle for targeted cancer biopsy.

Cancer microenvironment exhibits lower pH compared to healthy tissues, a characteristic which can be exploited using a pH-responsive needle to increase the accuracy of cancer biopsy. A needle, coated with pH-responsive polyaniline (PANI) nanoparticles (PANI-needle), is developed for the minimally invasive and quantitative pH analysis of tissue based on ratiometric photoacoustic (PA) imaging. The ratiometric PA signal from the PANI-needle within the 850-700 nm wavelength range shows a linear response as pH changes from 7.5 to 6.5. Owing to the high surface area of nanostructured PANI, the PA signal of PANI-needle exhibits a fast and reversible response of less than a few seconds. In a tissue-mimicking hydrogel phantom composed of two regions with different pH, PA ratios of PANI-needle successfully differentiate the local pH. The PANI-needle coupled with ultrasound-guided PA imaging is a promising technology for detection of malignant tissue through quantitative pH analysis during needle biopsy.

Esophageal stent fixation with endoscopic suturing device improves clinical outcomes and reduces complications in patients with locally advanced esophageal cancer prior to neoadjuvant therapy: a large multicenter experience.

BACKGROUND: Endoscopic placement of fully covered self-expanding metal stents (FCSEMS) to treat malignant dysphagia in patients with esophageal cancer significantly improves dysphagia; however, these stents have a high migration rate. AIM: To determine whether FCSEMS fixation using an endoscopic suturing device treated malignant dysphagia and prevented stent migration in patients with locally advanced esophageal cancer receiving neoadjuvant therapy when compared to patients with FCSEMS placement alone. METHOD: A review of patients with locally advanced esophageal cancer who underwent FCSEMS placement at 3 centers was performed. Patients were divided into two groups: Group A (n = 26) was composed of patients who underwent FCSEMS placement with suture placement, and Group B (n = 67) was composed of patients with FCSEMS placement alone. RESULTS: There were no significant differences between Groups A and B in demographics, and tumor characteristics. The technical success rate for stent placement was 100 %. There was no difference between Groups A and B in the median stent diameter and stent lengths. Mean dysphagia score obtained at 1 week after stent placement had improved significantly from baseline (2.4 and 1, respectively, p < 0.001). Patients had a median follow-up of 4 months. Immediate adverse events were mild chest discomfort in 4 patients in Group A and 2 patients in Group B (p = 0.05), and significant acid reflux in 3 patient in Group A compared to 2 patients in Group B (p = 0.1). The stent migration rate was significantly lower in Group A compared to compared to Group B (7.7 vs 26.9 %, respectively, p = 0.004). There was a delayed perforation in 1 patient and 1 death due to aspiration pneumonia in Group B. CONCLUSION: Fixation of esophageal FCSEMSs by using an endoscopic suturing device in patients receiving neoadjuvant therapy was shown to be feasible, safe, and relatively effective at preventing stent migration compared to those who had stent placed alone.

Holodiastolic Flow Reversal at the Descending Aorta on Cardiac Magnetic Resonance is Neither Sensitive Nor Specific for Significant Aortic Regurgitation in Patients with Congenital Heart Disease.

Holodiastolic flow reversal in the descending aorta on echocardiogram suggests significant aortic regurgitation. The study aim was to determine whether the presence of holodiastolic flow reversal on cardiac magnetic resonance imaging (MRI) correlates with aortic valve regurgitant fraction. We retrospectively reviewed 166 cardiac MRIs (64 % male, age 14.1 ± 9.5 years) from January 2011 to May 2012 where velocity mapping was acquired at both the aortic valve and the descending aorta at the level of the diaphragm. Descending aorta velocity maps were checked for baseline offset using a static reference region. Holodiastolic flow reversal was defined as flow reversal throughout diastole both before and after baseline correction. Significant aortic regurgitation was defined as regurgitant fraction >10 %. Aortic valve regurgitant fraction was <10 % in 144 patients (Group A), 10-20 % inclusive in 7 patients (Group B), and >20 % in 15 patients (Group C). Though the aortic valve regurgitant fraction was significantly higher for patients with holodiastolic flow reversal versus those without (8.5 ± 14.2 vs. 3.8 ± 6.6 %, p = 0.02), holodiastolic flow reversal was present in 32 Group A patients (22 %). In comparison, 4 Group B patients (57 %) and 7 Group C patients (47 %) had holodiastolic flow reversal. The sensitivity (Groups B and C) was 0.5, and the specificity (Group A) was 0.78. Holodiastolic flow reversal in the descending aorta on cardiac MRI was neither sensitive nor specific for predicting significant aortic regurgitation in this study population. Holodiastolic flow reversal in the absence of significant aortic regurgitation may be a relatively common finding in patients with congenital heart disease.