Identifying urban areas: A new approach and comparison of national urban metrics with gridded population data

The measurement of urbanization and other key urban indicators depends on how urban areas are defined. The Degree of Urbanization (DEGURBA) has been recently adopted to support international statistical comparability, but its rigid criteria for classify areas as urban/non-urban based upon fixed population size and density criteria is controversial. Here we present an alternative approach to urban classification, using a flexible range of population density \& count thresholds. We then compare how these thresholds affect estimation of urbanization and urban settlement counts across three of the most popular gridded population datasets (GPD). Instead of introducing further uncertainties by matching GPD to built-up area datasets, we classify urban areas in a purely spatial demographic way. By calculating national urban shares and urban area counts, we highlight the often overlooked uncertainties when using GPD. We find that the choice of GPD is generally the dominant factor in altering both of these urban indicators but the choice of urban criteria is also important. Overall, this alternative urban classification method offers a more flexible approach to human settlements classification that can be applied globally for comparative research.

Metabolic Tumour Volume from PSMA PET/CT Scans of Prostate Cancer Patients during Chemotherapy—Do Different Software Solutions Deliver Comparable Results?

(1) Background: Prostate-specific membrane antigen (PSMA)-derived tumour volume (PSMA-TV) and total lesion PSMA (TL-PSMA) from PSMA PET/CT scans are promising biomarkers for assessing treatment response in prostate cancer (PCa). Currently, it is unclear whether different software tools for assessing PSMA-TV and TL-PSMA produce comparable results. (2) Methods: 68Ga-PSMA PET/CT scans from n = 21 patients with castration-resistant PCa (CRPC) receiving chemotherapy were identified from our single-centre database. PSMA-TV and TL-PSMA were calculated with Syngo.via (Siemens) as well as the freely available Beth Israel plugin for FIJI (Fiji Is Just ImageJ) before and after chemotherapy. While statistical comparability was illustrated and quantified via Bland-Altman diagrams, the clinical agreement was estimated by matching PSMA-TV, TL-PSMA and relative changes of both variables during chemotherapy with changes in serum PSA (ΔPSA) and PERCIST (Positron Emission Response Criteria in Solid Tumors). (3) Results: Comparing absolute PSMA-TV and TL-PSMA as well as Bland–Altman plotting revealed a good statistical comparability of both software algorithms. For clinical agreement, classifying therapy response did not differ between PSMA-TV and TL-PSMA for both software solutions and showed highly positive correlations with BR. (4) Conclusions: due to the high levels of statistical and clinical agreement in our CRPC patient cohort undergoing taxane chemotherapy, comparing PSMA-TV and TL-PSMA determined by Syngo.via and FIJI appears feasible.

Does Anterior Tunnelling Really Help in Underlay Type I Tympanoplasty?

Introduction Stabilizing the graft can be difficult with the conventional method of underlay tympanoplasty when the tympanic membrane perforation is subtotal, large or anteriorly placed with thin anterior rim. Tympanoplasty with anterior tunnelling has been tried to overcome this problem. Materials and Methods A prospective study over two-year period was carried out with follow up for three months on 59 patients under two groups- the underlay tympanoplasty with anterior tunnelling and the conventional tympanoplasty with anterior tucking for comparison in terms of pre-and post-operative anatomical correction and physiological improvements Results Follow up at 6 weeks and 12 weeks post operatively gives statistically comparable graft take up, hearing result and residual perforations. Discussion Among various techniques of dealing with these types of perforations, statistical comparability of the two groups brings in an acceptability to this simple but satisfying procedure of the underlay tympanoplasty with anterior tunnelling. Conclusion Underlay tympanoplasty technique (type-I) for subtotal, large or anteriorly placed perforations with thin anterior rim, can be managed by combining with anterior tunnelling which provides at least comparable results (if not more security against graft medialization) in respect of anatomical closure of perforations and hearing outcomes.