Dataset on renal tumor diameter assessment by multiple observers in normal-dose and low-dose CT.

Computed tomography-based active surveillance is increasingly used to manage small renal tumors, regardless of patient age. However, there is an unmet need for decreasing radiation exposure while maintaining the necessary accuracy and reproducibility in radiographic measurements, allowing for detecting even minor changes in renal mass size. In this article, we present supplementary data from a multiobserver investigation. We explored the accuracy and reproducibility of low-dose CT (75% dose reduction) compared to normal-dose CT in assessing maximum axial renal tumor diameter. Open-access CT datasets from the 2019 Kidney and Kidney Tumor Segmentation Challenge were used. A web-based platform for assessing observer performance was used by six radiologist observers to obtain and provide data on tumor diameters and accompanying viewing settings, in addition to key images of each measurement and an interactive module for exploring diameter measurements. These data can serve as a baseline and inform future studies investigating and validating lower-dose CT protocols for active surveillance of small renal masses.

Reference intervals and age and gender dependency for arterial blood gases and electrolytes in adults.

BACKGROUND: Although results from blood gas analyzers are frequently used in clinical work surprisingly few and small studies have examined reference intervals for arterial blood gases and acid-base status. We have established reference values based on a large group of healthy people with a wide age distribution. METHODS: A group of medical students (n=182) aged 20-32 years old and a group of health professionals aged 21-76 years were used in this study. Arterial samples were analyzed on the blood gas analyzer ABL from Radiometer(TM). Age and gender dependency was examined for all analytes and reference intervals were calculated non-parametrically. RESULTS: Females had significantly higher pH and lower PaCO(2) (partial pressure of carbon dioxide in an arterial sample), base excess (BE, standard, extra cellular fluid), plasma standard and actual HCO(3), when compared to males (p<0.01). However, the differences were minor and common reference intervals were therefore also determined, generally at the same level as previously published. The lactate values were similar among the genders but with a high upper limit of 2.5 mmol/L. The non-smoker group of females and males had similar PaO(2) values (partial pressure of oxygen in an arterial sample). However, an age dependent effect was found and PaO(2) decreased by 0.29 kPa per decade (confidence interval of slope -0.11 to -0.47 kPa). Electrolytes and anion gap results depicted smaller differences from previous published reference intervals for sodium (136-141 mmol/L) and anion gap (10-16 mmol/L, with potassium included or 6-12 mmol/L without potassium). CONCLUSIONS: Reference intervals for analytes on modern blood gas analyzers were established on a large group of healthy people. Gender and age dependency is generally without clinical importance, except for a lower PaCO(2) in women and a decreasing PaO(2) with higher age.

Mathematical modelling of the acid-base chemistry and oxygenation of blood: a mass balance, mass action approach including plasma and red blood cells.

Mathematical models of the acid-base chemistry of blood based upon mass action and mass balance equations have become popular as diagnostic tools in intensive care. The reference models using this approach are those based on the strong ion approach, but these models do not currently take into account the effects of oxygen on the buffering characteristics of haemoglobin. As such these models are limited in their ability to simulate physiological situations involving simultaneous changes of O(2) and CO(2) levels in the blood. This paper describes a model of acid-base chemistry of blood based on mass action and mass balance equations and including the effects of oxygen. The model is used to simulate the mixing of venous blood with the same blood at elevated O(2) and reduced CO(2) levels, and the results compared with the mixing of blood sampled from 21 healthy subjects. Simulated values of pH, PCO(2), PO(2) and SO(2) in the mixed blood compare well with measured values with small bias (i.e. 0.000 pH, -0.06 kPa PCO(2), -0.1% SO(2), -0.02 kPa PO(2)), and values of standard deviations (i.e. 0.006 pH, 0.11 kPa PCO(2), 0.8% SO(2), 0.13 kPa PO(2)) comparable to the precision seen in direct measurement of these variables in clinical practice. These results indicate that the model can reliably simulate the mixing of blood and has potential for application in describing physiological situations involving the mixing of blood at different O(2) and CO(2) levels such as occurs in the mixing of lung capillary and shunted pulmonary blood.