A multichannel feature-based approach for longitudinal lung CT registration in the presence of radiation induced lung damage

Quantifying parenchymal tissue changes in the lungs is imperative in furthering the study of radiation induced lung damage (RILD). Registering lung images from different time-points is a key step of this process. Traditional intensity-based registration approaches fail this task due to the considerable anatomical changes that occur between timepoints. This work proposes a novel method to successfully register longitudinal pre- and post-radiotherapy (RT) lung computed tomography (CT) scans that exhibit large changes due to RILD, by extracting consistent anatomical features from CT (lung boundaries, main airways, vessels) and using these features to optimise the registrations. Pre-RT and 12 month post-RT CT pairs from fifteen lung cancer patients were used for this study, all with varying degrees of RILD, ranging from mild parenchymal change to extensive consolidation and collapse. For each CT, signed distance transforms from segmentations of the lungs and main airways were generated, and the Frangi vesselness map was calculated. These were concatenated into multi-channel images and diffeomorphic multichannel registration was performed for each image pair using NiftyReg. Traditional intensity-based registrations were also performed for comparison purposes. For the evaluation, the pre- and post-registration landmark distance was calculated for all patients, using an average of 44 manually identified landmark pairs per patient. The mean (standard deviation) distance for all datasets decreased from 15.95 (8.09) mm pre-registration to 4.56 (5.70) mm post-registration, compared to 7.90 (8.97) mm for the intensity-based registrations. Qualitative improvements in image alignment were observed for all patient datasets. For four representative subjects, registrations were performed for three additional follow-up timepoints up to 48 months post-RT and similar accuracy was achieved. We have demonstrated that our novel multichannel registration method can successfully align longitudinal scans from RILD patients in the presence of large anatomical changes such as consolidation and atelectasis, outperforming the traditional registration approach both quantitatively and through thorough visual inspection.

In Silico Ventilation Within the Dose-Volume is Predictive of Lung Function Post-radiation Therapy in Patients with Lung Cancer

Lung cancer is a leading cause of death worldwide. Radiation therapy (RT) is one method to treat this disease. A common side effect of RT for lung cancer is radiation-induced lung damage (RILD) which leads to loss of lung function. RILD often compounds pre-existing smoking-related regional lung function impairment. It is difficult to predict patient outcomes due to large variability in individual response to RT. In this study, the capability of image-based modelling of regional ventilation in lung cancer patients to predict lung function post-RT was investigated. Twenty-five patient-based models were created using CT images to define the airway geometry, size and location of tumour, and distribution of emphysema. Simulated ventilation within the 20 Gy isodose volume showed a statistically significant negative correlation with the change in forced expiratory volume in 1 s 12-months post-RT (p = 0.001, R = - 0.61). Patients with higher simulated ventilation within the 20 Gy isodose volume had a greater loss in lung function post-RT and vice versa. This relationship was only evident with the combined impact of tumour and emphysema, with the location of the emphysema relative to the dose-volume being important. Our results suggest that model-based ventilation measures can be used in the prediction of patient lung function post-RT.

Prediction of a positive circumferential resection margin at surgery following neoadjuvant chemotherapy for adenocarcinoma of the oesophagus

Background

A positive circumferential resection margin (CRM) has been associated with higher rates of locoregional recurrence and worse survival in oesophageal cancer. The aim of this study was to establish if clinicopathological and radiological variables might predict CRM positivity in patients who received neoadjuvant chemotherapy before surgery for oesophageal adenocarcinoma.

Methods

Multivariable analysis of clinicopathological and CT imaging characteristics considered potentially predictive of CRM was performed at initial staging and following neoadjuvant chemotherapy. Prediction models were constructed. The area under the curve (AUC) with 95% confidence intervals (c.i.) from 1000 bootstrapping was assessed.

Results

A total of 223 patients were included in the study. Poor differentiation (odds ratio (OR) 2·84, 95 per cent c.i. 1·39 to 6·01) and advanced clinical tumour status (T3-4) (OR 2·93, 1·03 to 9·48) were independently associated with an increased CRM risk at diagnosis. CT-assessed lack of response (stable or progressive disease) following chemotherapy independently corresponded with an increased risk of CRM positivity (OR 3·38, 1·43 to 8·50). Additional CT evidence of local invasion and higher CT tumour volume (14 cm3) improved the performance of a prediction model, including all the above parameters, with an AUC (c-index) of 0·76 (0·67 to 0·83). Variables associated with significantly higher rates of locoregional recurrence were pN status (P = 0·020), lymphovascular invasion (P = 0·007) and poor response to chemotherapy (Mandard score 4-5) (P = 0·006). CRM positivity was associated with a higher locoregional recurrence rate, but this was not statistically significant (P = 0·092).

Conclusion

The presence of advanced cT status, poor tumour differentiation, and CT-assessed lack of response to chemotherapy, higher tumour volume and local invasion can be used to identify patients at risk of a positive CRM following neoadjuvant chemotherapy.

Impact of incremental circumferential resection margin distance on overall survival and recurrence in oesophageal adenocarcinoma

Background

Previous analyses of the oesophageal circumferential resection margin (CRM) have focused on the prognostic validity of two different definitions of a positive CRM, that of the College of American Pathologists (tumour at margin) and that of the Royal College of Pathologists (tumour within 1 mm). This study aimed to analyse the validity of these definitions and explore the risk of recurrence and survival with incremental tumour distances from the CRM.

Methods

This cohort study included patients who underwent resection for adenocarcinoma of the oesophagus between 2000 and 2014. Kaplan-Meier and Cox regression analyses were performed to determine the hazard ratio (HR) with 95 per cent confidence intervals for recurrence and mortality in CRM increments: tumour at the cut margin, extending to within 0·1-0·9, 1·0-1·9, 2·0-4·9 mm, and 5·0 mm or more from the margin.

Results

A total of 444 patients were included in the study. Kaplan-Meier and unadjusted analyses showed a significant incremental improvement in overall survival (P < 0·001) and recurrence (P for trend < 0·001) rates with increasing distance from the CRM. Tumour distance of 2·0 mm or more remained a significant predictor of survival on multivariable analysis (HR for risk of death 0·66, 95 per cent c.i. 0·44 to 1·00). Multivariable analysis of overall survival demonstrated a significant difference between a positive and negative CRM with the Royal College of Pathologists' definition (HR 1·37, 1·01 to 1·85), but not with the College of American Pathologists' definition (HR 1·22, 0·90 to 1·65).

Conclusion

This study demonstrated an incremental improvement in survival and recurrence rates with increasing tumour distance from the CRM.

UK Consensus on Normal Tissue Dose Constraints for Stereotactic Radiotherapy

Six UK studies investigating stereotactic ablative radiotherapy (SABR) are currently open. Many of these involve the treatment of oligometastatic disease at different locations in the body. Members of all the trial management groups collaborated to generate a consensus document on appropriate organ at risk dose constraints. Values from existing but older reviews were updated using data from current studies. It is hoped that this unified approach will facilitate standardised implementation of SABR across the UK and will allow meaningful toxicity comparisons between SABR studies and internationally.

Association between ambient air pollution and proliferation of umbilical cord blood cells

It has been established as a common knowledge that ambient air pollution (AAP) has an adverse effect on human health. The pathophysiological mechanism of this impact is likely to be related to the oxidative stress. In the current study we estimate the association between AAP and cell proliferation (CP) of umbilical cord blood cells, representing maternal organism most proximal to the fetal body. Blood samples were tested for proliferation in 292 enrolled Arab-Bedouin women at delivery (July 2012-March 2013). The estimates of AAP were defined by a hybrid satellite based model predicting both PM_2.5 (particles<2.5µm in diameter) and PM₁₀ (particles<10µm in diameter) as well as monitoring stations for gaseous air pollutants. Risk estimates of pollution exposure were adjusted to medical history, household risk factors and meteorological factors on the day of delivery or one week prior. Ambient ozone (O₃) levels on 1, 2, 3and 4 days prior to delivery were associated with lower CP (Prevalence ratio (PR)=0.92, 0.92, 0.93, 0.93, respectively). Increase in inter-quartile range (IOR) of PM_2.5 one day before delivery was associated with 9% increase in CP levels (PR=1.09). The positive direction in association was changed to negative association with CP for PM_2.5 levels measured at more distant time periods (PR=0.90 and 0.93 for lags 5 and 6 days, respectively). Investigation of PM₁₀ levels indicated a similar pattern (PR=1.05 for pollution values recorded one day before delivery and 0.93 and 0.95 for lags of 5 and 6 days, respectively). Carbon monoxide (CO) levels were associated with lower CP on the day of delivery and 1day prior (PR=0.92 and PR=0.94). To conclude, the levels of cell proliferation of umbilical cord blood cells appear to be associated with the AAP. More studies are needed to support our findings.

Nitrogen Dioxide pollution and hazardous household environment: what impacts more congenital malformations

Nitrogen Dioxide (NO2) is a product of fuel combustion originating mainly from industry and transportation. Studies suggest an association between NO2 and congenital malformations (CM). We investigated an independent effect of NO2 on CM by adjusting to individual factors and household environment in 1024 Bedouin-Arab pregnant women in southern Israel. This population is characterised by high rates of CMs, frequent consanguineous marriages, paternal smoking, temporary housing and usage of open fire for heat cooking. Information on household risk factors was collected during an interview. Ambient measurements of 24-h average NO2 and meteorological conditions were obtained from 13 local monitors. Median value of daily NO2 measured in the area was 6.78ppb. CM was diagnosed in 8.0% (82) of offspring. Maternal NO2 exposure during the 1st trimester >8.6ppb was significantly associated with minor CM (RR=2.68, p=0.029). Major CM were independently associated with maternal juvenile diabetes (RR=9.97, p-value=0.002) and heating by open fire (RR=2.00, p-value=0.049), but not NO2 exposure. We found that NO2 emissions had an independent impact only on minor malformations, whereas major malformations depended mostly on the household environment. Antepartum deaths were associated by maternal morbidity.

Should testosterone replacement be offered to hypogonadal men treated previously for prostatic carcinoma?

Androgen administration can cause prostate cancer progression, and androgen deprivation therapy is a commonly used therapeutic modality in the treatment of prostate cancer. In trying to answer the posed clinical question, this article reviews the risks and benefits of testosterone replacement therapy in this setting and the published data from clinical series. Recommendations are made based on the available evidence.

Familial factor VII deficiency with foetal and neonatal fatal cerebral haemorrhage associated with homozygosis to Gly180Arg mutation

Inherited factor VII (FVII) deficiency is a rare autosomal recessive disorder with a wide heterogeneous clinical pattern. Intracranial haemorrhage in infants has been previously reported in the severe form of the FVII deficiency and it has a high fatality rate. We report a family with high consanguineous relations, who experienced death of two baby girls, the first with prenatal manifestation of foetal hydrocephalus secondary to intracranial bleeding and the second with postnatal intracranial bleeding, both with less than 1% activity of FVII. Genetic analysis revealed that both parents are heterozygous and both daughters homozygous for a point mutation gG9639A in exon 7, predicting Gly180Arg substitution. This mutation was described previously in a compound heterozygous patient with mild bleeding manifestation. It seems that in this family, the mutation in its homozygous state is fatal and the lethal clinical expression can appear in utero at an early stage of gestation.

Voluntary dehydration among elementary school children residing in a hot arid environment

BACKGROUND

Voluntary dehydration is a condition where humans do not drink appropriately in the presence of an adequate fluid supply. This may adversely affect their physical and intellectual performance. The present study aimed to describe the prevalence of voluntary dehydration among elementary school children of different ethnicities and countries of birth.

METHODS

Four hundred and twenty-nine elementary school children, aged 8-10 years, from four subpopulations (Israeli-born Jewish and Bedouin-Arab children, and immigrant children who recently arrived to Israel from Eastern Europe and from Ethiopia) were studied. The level of dehydration was determined by noontime urine osmolality, from samples taken over 1 week in mid-summer. Urine osmolality <500 mOsmol kg(-1) H(2)O was considered to be an appropriate level of hydration.

RESULTS

Mean urine osmolality was 862 +/- 211 mOsmol kg(-1) H(2)O. Osmolality above 800 mOsmol kg(-1) H(2)O was detected in 67.5% of the urine samples; among these, 25% were above 1000 mOsmol kg(-1) H(2)O. The most dehydrated group was that of Israeli-born Jewish children, whereas the Bedouin-Arab children were the least dehydrated.

CONCLUSIONS

A high proportion of children who reside in a hot and arid environment were found to be in a state of moderate to severe dehydration. Bedouin ethnicity was associated with better hydration, whereas Israeli-born Jews were most severely dehydrated. Educational intervention programmes promoting water intake should start in early childhood and continue throughout life.