Quantifying the Changes in the Tumour Vascular Micro-environment in Spinal Metastases Treated with Stereotactic Body Radiotherapy - A Single Arm Prospective Study

BackgroundThe primary objective was to quantify changes in vascular micro-environment in spinal metastases (SM) patients treated with stereotactic body radiotherapy (SBRT) with multi-parametric dynamic contrast enhanced (DCE) magnetic resonance imaging (MRI). The secondary objective was to study plasma biomarkers related to endothelial apoptosis.Patients and methodsPatients were imaged with DCE-MRI at baseline/1-week/12-weeks post-SBRT. Metrics including normalised time-dependent leakage (Ktrans), permeability surface product (PS), fractional plasma volume (Vp), extracellular volume (Ve) and perfusion (F) were estimated using distributed parameter model. Serum acid sphingomyelinase (ASM) and sphingosine-1-phosphate (S1P) were quantified using ELISA. Clinical outcomes including physician-scored and patient-reported toxicity were collected.ResultsTwelve patients (with varying primary histology) were recruited, of whom 10 underwent SBRT. Nine patients (with 10 lesions) completed all 3 imaging assessment timepoints. One patient died due to pneumonia (unrelated) before follow-up scans were performed. Median SBRT dose was 27 Gy (range: 24–27) over 3 fractions (range: 2–3). Median follow-up for alive patients was 42-months (range: 22.3–54.3), with local control rate of 90% and one grade 2 or higher toxicity (vertebral compression fracture). In general, we found an overall trend of reduction at 12-weeks in all parameters (Ktrans/PS/Vp/Ve/F). Ktrans and PS showed a reduction as early as 1-week. Ve/Vp/F exhibited a slight rise 1-week post-SBRT before reducing below the baseline value. There were no significant changes, post-SBRT, in plasma biomarkers (ASM/S1P).ConclusionsTumour vascular micro-environment (measured by various metrics) showed a general trend towards downregulation post-SBRT. It is likely that vascular-mediated cell killing contributes to excellent local control rates seen with SBRT. Future studies should evaluate the effect of SBRT on primary-specific spinal metastases (e.g., renal cell carcinoma).Key words: spine metastases, stereotactic body radiotherapy, DCE-MRI, endothelial apoptosis     

Training Standards and Recommendations for Intervention on Chronic Total Occlusions

Despite major advances in coronary intervention, the recanalization of a chronic total occlusion (CTO) remains a challenge for many interventional cardiologists. Complex anatomy and lesion characteristics demand a special set of skills for procedural success. Provided patient selection is appropriate, CTO intervention can confer a variety of benefits including relief of angina, improvement in left ventricular function and reduction in ischemic burden. The chances of procedural success are enhanced by having a dedicated CTO program. This involves adequate training of staff, quality control and availability of equipment. A diverse toolkit allows variation in strategy and increases procedural success. Further, skills and equipment are required to manage complications like vessel dissection, perforation and the resultant ischemic or mechanical complications. These procedures can often be lengthy and giving careful consideration to peri-procedural issues like radiation exposure and contrast dose plays a vital role in ensuring optimal patient outcomes and radiation hygiene. In this article we review the evidence behind indications for CTO intervention and discuss the development of a CTO program.     

Viable approach to manage superficial enamel discoloration

Esthetics is a primary concern amongst young patients and represents a challenge to the dentist. Discolored teeth are frequently seen in the general population. Several techniques have been devised to minimize or completely eliminate tooth discoloration. This case report highlights the successful management of enamel discoloration via modified microabrasion technique followed by in office bleaching.     

Vertical root fracture resistance and dentinal crack formation of root canal-treated teeth instrumented with different nickel–titanium rotary systems: an in-vitro study

Odontology - To compare the vertical root fracture (VRF) resistance of root canal-treated teeth instrumented with four different nickel–titanium (NiTi) rotary file systems and examine the...