Characterization of suboptimal responses to fetoscopic endoluminal tracheal occlusion in congenital diaphragmatic hernia

INTRODUCTION

To characterize the changes in fetal lung volume following endoluminal tracheal occlusion (FETO) that are associated with infant survival and need for extracorporeal membrane oxygenation (ECMO) in congenital diaphragmatic hernia (CDH).

METHODS

Fetuses with CDH who underwent FETO at a single institution were included. CDH cases were reclassified by MRI metrics, [observed-to-expected total lung volume (O/E TLV) and percent liver herniation]. The percent changes of MRI metrics after FETO were calculated. ROC-derived cutoffs of these changes were derived to predict infant survival to discharge. Regression analyses were done to determine the association between these cutoffs with infant survival and ECMO need, adjusted for site of CDH, gestational age at delivery, fetal sex, and CDH severity.

RESULTS

Thirty CDH cases were included. ROC analysis demonstrated that post-FETO increases in O/E TLV had an area under the curve of 0.74 (p=0.035) for the prediction of survival to hospital discharge; a cutoff of less than 10% was selected. Fetuses with a <10% post-FETO increase in O/E TLV had lower survival to hospital discharge [44.8% vs. 91.7%; p=0.018] and higher ECMO use [61.1% vs. 16.7%; p=0.026] compared to those with an O/E TLV increase ≥10%. Similar results were observed when the analyses were restricted to left-sided CDH cases. A post-FETO <10% increase in O/E TLV was independently associated with lower survival at hospital discharge (aOR: 0.073, 95% CI: 0.008 - 0.689; p=0.022) and at 12 months of age (aOR: 0.091, 95% CI: 0.01 - 0.825; p=0.036) as well as with higher ECMO use (aOR: 7.88, 95% CI: 1.31 - 47.04; p=0.024).

DISCUSSION/CONCLUSION

Fetuses with less than 10% increase in in O/E TLV following the FETO procedure are at increased risk for requiring ECMO and for death in the postnatal period when adjusted for gestational age at delivery, CDH severity, and other confounders.

P01.01.A Lesion-Function Analysis from Multimodal Imaging and Normative Brain Atlases for Prediction of Cognitive Deficits in Glioma Patients

Background

Cognitive deficits are common in glioma patients following multimodality therapy, but the relative impact of different types and locations of treatment-related brain damage and recurrent tumors on cognition is not well understood.

Material and Methods

In 121 WHO Grade III/IV glioma patients, structural MRI, O-(2-[18F]fluoroethyl)-L-tyrosine FET-PET, and neuropsychological testing were performed at a median interval of 14 months (range, 1-214 months) after therapy initiation. Resection cavities, T1-enhancing lesions, T2/FLAIR hyperintensities, and FET-PET positive tumor sites were semiautomatically segmented and elastically registered to a normative, resting state (RS) fMRI-based functional cortical network atlas and to the JHU atlas of white matter (WM) tracts, and their influence on cognitive test scores relative to a cohort of matched healthy subjects was assessed.

Results

T2/FLAIR hyperintensities presumably caused by radiation therapy covered more extensive brain areas than the other lesion types and significantly impaired cognitive performance in many domains when affecting left-hemispheric RS-nodes and WM-tracts as opposed to brain tissue damage caused by resection or recurrent tumors. Verbal episodic memory proved to be especially vulnerable to T2/FLAIR abnormalities affecting the nodes and tracts of the left temporal lobe.

Conclusion

In order to improve radiotherapy planning, publicly available brain atlases, in conjunction with elastic registration techniques, should be used, similar to neuronavigation in neurosurgery.

P13.03.A Radiomics for the non-invasive assessment of the PDL-1 expression in patients with non-small cell lung cancer brain metastases

BACKGROUND

The expression level of programmed cell death ligand 1 (PDL-1) might be an indicator for response to immunotherapy using checkpoint inhibitors in patients with non-small cell lung cancer (NSCLC). As intra-tumoral differences and discrepancies between the PDL-1 expression in the primary tumor and the brain metastases may occur, a method for a reliable non-invasive assessment of the intracranial PDL-1 expression would be of clinical value. We evaluated the potential of MRI radiomics for a non-invasive assessment of the PDL-1 expression in patients with NSCLC brain metastases.

PATIENTS AND METHODS

Fifty-three patients with brain metastases from NSCLC from two university brain tumor centers (group 1, 36 patients; group 2, 17 patients) underwent tumor resection with subsequent immunohistochemical assessment of the PDL-1 expression. Brain metastases were manually segmented on preoperative T1-weighted contrast-enhanced MRI. Group 1 was used for model training and validation, group 2 for model testing. After image pre-processing and radiomics feature extraction from T1-weighted contrast-enhanced MRI, a test-retest analysis was performed to identify robust features prior to feature selection. The radiomics model was trained and validated using five-fold cross validation. Finally, the best performing radiomics model was applied to the test data. Diagnostic performance was evaluated using receiver operating characteristic (ROC) analyses.

RESULTS

An intracranial PDL-1 expression was found by immunohistochemistry in 18 of 36 patients (50%) in group 1, and 7 of 17 patients (41%) in group 2. Univariate analysis identified tumor volume as a significant clinical feature for PDL-1 expression (area under the ROC curve (AUC), 0.77). A random forest classifier using a four-parameter radiomics signature including tumor volume yielded an AUC of 0.83 ± 0.18 in the training data (group 1). Finally, the classifier achieved an AUC of 0.84 in the external test data (group 2).

CONCLUSION

The developed radiomics classifiers allows a non-invasive assessment of the intracranial PD-L1 expression in patients with NSCLC brain metastases with a high diagnostic performance.

P01.02.B Case Report: Disruption of Resting-State Networks and Cognitive Deficits After Whole Brain Irradiation for Singular Brain Metastasis

Background

Long-term survivors of whole brain radiation (WBRT) are at significant risk for developing cognitive deficits, but knowledge about the underlying pathophysiological mechanisms is limited. Therefore, we here report a rare case with a singular brain metastasis treated by resection and WBRT that survived for more than 10 years where we investigated the integrity of brain networks using resting-state functional MRI.

Material and Methods

A female patient with a left frontal non-small cell lung cancer (NSCLC) brain metastasis had resection and postoperative WBRT (30.0 in 3.0Gy fractions) and stayed free from brain metastasis recurrence for a follow-up period of 11 years. Structural magnetic resonance imaging (MRI) and amino acid [O-(2-[18F]fluoroethyl)-L-tyrosine] positron emission tomography (FET PET) were repeatedly acquired. At the last follow up, neurocognitive functions and resting-state functional connectivity (RSFC) using resting-state fMRI were assessed. Within-network and inter-network connectivity of seven resting-state networks were computed from a connectivity matrix. All measures were compared to a matched group of 10 female healthy subjects.

Results

At the 11-year follow-up, T2/FLAIR MR images of the patient showed extended regions of hyper-intensities covering mainly the white matter of the bilateral dorsal frontal and parietal lobes while sparing most of the temporal lobes. Compared to the healthy subjects, the patient performed significantly worse in all cognitive domains that included executive functions, attention and processing speed, while verbal working memory, verbal episodic memory, and visual working memory were left mostly unaffected. The connectivity matrix showed a heavily disturbed pattern with a widely distributed, scattered loss of RSFC. The within-network RSFC revealed a significant loss of connectivity within all seven networks where the dorsal attention and fronto-parietal

control networks were affected most severely. The inter-network RSFC was significantly reduced for the visual, somato-motor, and dorsal and ventral attention networks.

Conclusion

As demonstrated here in a patient with a metastatic NSCLC and long-term survival, WBRT may lead to extended white matter damage and cause severe disruption of the RSFC in multiple resting state networks. In consequence, executive functioning which is assumed to depend on the interaction of several networks may be severely impaired following WBRT apart from the well-recognized deficits in memory function.

PL01.6.A Radiomics outperforms semantic features for prediction of response to stereotactic radiosurgery in brain metastases

Background

Brain metastases show different patterns of contrast enhancement, potentially reflecting hypoxic and necrotic tumor regions with reduced radiosensitivity. An objective evaluation of these patterns might allow a prediction of response to radiotherapy. We therefore investigated the potential of MRI radiomics in comparison with the visual assessment of semantic features to predict early response to stereotactic radiosurgery in patients with brain metastases.

Material and Methods

In this retrospective study, 150 patients with 308 brain metastases from solid tumors (NSCLC in 53% of patients) treated by stereotactic radiosurgery (single dose of 17-20 Gy) were evaluated. The response of each metastasis (partial or complete remission vs. stabilization or progression) was assessed within 180 days after radiosurgery. Patterns of contrast enhancement in the pre-treatment T1-weighted MR images were either visually classified (homogenous, heterogeneous, necrotic ring-like) or subjected to a radiomics analysis. Random forest models were optimized by cross-validation and evaluated in a hold-out test data set (30% of metastases).

Results

In total, 221/308 metastases (72%) responded to radiosurgery. The optimal radiomics model comprised 10 features and outperformed the model solely based on semantic features in the test data set (AUC, 0.71 vs. 0.56; accuracy, 69% vs. 54%). The diagnostic performance could be further improved by combining semantic and radiomics features resulting in an AUC of 0.74 and an accuracy of 75% in the test data set.

Conclusion

The developed radiomics model allowed prediction of early response to radiosurgery in patients with brain metastases and outperformed the visual assessment of patterns of contrast enhancement.

KS05.5.A Alterations in white matter fiber density associated with structural MRI and metabolic PET lesions following multimodal therapy in glioma patients

Background

In glioma patients, multimodal therapy and recurrent tumor result in local brain tissue changes, characterized by pathologic findings in structural MRI and metabolic PET images. Little is known about these different lesion types’ impact on the local white matter fiber architecture and clinical outcome.

Patients and Methods

This study included data from 121 pretreated patients (median age, 52 years; ECOG, 01) with histomolecularly characterized glioma (WHO grade IV glioblastoma, n=81; WHO grade III anaplastic astrocytoma, n=28; WHO grade III anaplastic oligodendroglioma, n=12), who had a resection, radiotherapy, alkylating chemotherapy, or combinations thereof. After a median time of 14 months (range, 1-214 months), post-therapeutic structural and metabolic findings were evaluated using anatomical MRI and O-(2-[18F]fluoroethyl)-L-tyrosine (FET) PET acquired on a 3T hybrid PET/MR scanner. Local fiber density was estimated from tractography based on highangular resolution diffusion-weighted imaging. A cohort of 121 healthy subjects selected from the 1000BRAINS study and matched for age, gender and education served as a control group.

Results

The median volume of resection cavities, contrast-enhancing regions, regions with pathologically increased FET uptake, and T2/FLAIR hyperintense regions amounted to 20.9, 7.9, 30.3, and 53.4 mL, respectively. Compared to the control group, the average local fiber density in these regions was significantly reduced (p&lt;0.001). Resection cavities showed the highest reduction, followed by contrast-enhancing lesions and metabolically active tumors on FET PET (relative fiber density reduction, -87%, -65%, -55%, respectively). The local fiber density was inversely related (p=0.005) to the FET uptake in recurrent tumors. T2/FLAIR hyperintense lesions, either assigned to peritumoral edema in recurrent glioma or radiation-induced gliosis, had a comparable impact on reducing fiber density (48% and 41%, respectively). The total fiber loss (average fiber loss multiplied by lesion volume) associated with contrast-enhancing lesions (p=0.006) and T2/FLAIR hyperintense lesions (p=0.013) had a significant impact on the general performance status of the patients (ECOG score).

Conclusions

Our results suggest that apart from resection cavities, reduction in local fiber density is greatest in contrast-enhancing recurrent tumors, but total fiber loss induced by edema or gliosis has an equal detrimental effect on the patients’ performance due to the larger volume affected.

Funding

Funded by the 1000BRAINS study (INM, Research Centre Juelich, Germany), Horizon 2020 (Grant No. 945539 (HBP SGA3; SC)), and Heinz Nixdorf Foundation.

P15.05.A Prediction of response to lomustine-based chemotherapy in glioma patients at relapse using MRI and FET PET

Background

This study evaluates O-(2-[18F]fluoroethyl)-L-tyrosine (FET) PET and contrast-enhanced MRI for early response assessment in glioma patients at relapse treated with lomustine-based chemotherapy.

Material and Methods

Thirty-seven adult patients with WHO CNS Grade 3 or 4 gliomas at relapse (glioblastoma, 70%; median number of relapses, 1) were retrospectively identified. Besides MRI, serial FET PET scans were performed at baseline and early after chemotherapy initiation (median number of cycles, 2). Mean and maximum tumor-to-brain ratios (TBR), metabolic tumor volumes (MTV), the occurrence of distant hotspots with a mean TBR &gt; 1.6 at follow-up, and dynamic parameters (i.e., time-to-peak and slope) were derived from all FET PET scans. Threshold values of PET parameters were defined using receiver operating characteristic analyses to predict progression-free survival (PFS) of ≥6 months and overall survival (OS) of ≥12 months. MRI response assessment was based on RANO criteria. The predictive value of FET PET parameters and RANO criteria were subsequently evaluated using univariate and multivariate survival estimates.

Results

After treatment initiation, the median follow-up time was 11 months (range, 3-71 months). Maximum TBR and MTV (threshold, ≤0%) and RANO criteria predicted a significantly longer PFS (all P&lt;0.001) and OS (all P&lt;0.03). At follow-up FET PET imaging, the occurrence of new distant hotspots (n≥1) predicted a worse outcome, with significantly shorter PFS (P=0.001) and OS (P&lt;0.001). Dynamic PET parameters did not predict a significantly longer PFS or OS (P&gt;0.05). Multivariate survival analyses revealed that new distant hotspots at follow-up had the highest level of significance to predict non-response (P=0.002; hazard ratio, 5.722), independent of RANO criteria, IDH mutation status, and O6-methylguanine-DNA-methyltransferase promoter methylation.

Conclusion

FET PET seems to be a powerful tool for identifying responders to lomustine-based chemotherapy early after treatment initiation.

P17.19.B Incidence of treatment-associated imaging changes in newly diagnosed MGMT promoter-methylated glioblastoma treated with cilengitide (EORTC 26071 - CENTRIC study): interim analysis

Background

In patients with glioblastoma, radiological recurrence of enhancing tissue after chemoradiotherapy can originate from progressive disease (PD) or from pseudoprogression/treatment-associated changes. There are no widely approved consensus criteria for treatment-associated changes. In the randomised EORTC-CENTRIC study (NCT00689221), patients with MGMT promoter-methylated glioblastoma were treated with chemoradiotherapy or chemoradiotherapy with cilengitide, an integrin inhibitor. We assessed the rate of treatment-associated changes in these groups according to the modified response assessment in neuro-oncology (RANO) criteria of 2017.

Methods

CENTRIC patients from both study arms with ≥3 follow-up MRIs were included. Preliminary PD (PPD) was defined as a ≥25% increase of the sum of perpendicular diameter (SPD) of a new or increasing lesion compared to baseline or nadir on the T1-MRI with gadolinium. Subsequent PD was defined as a second ≥25% increase of the SPD, at least 4 weeks later, or as a new lesion outside the radiation field. Treatment-associated changes were defined as stabilisation on ≥2 follow-up MRIs after PPD, each one 4 weeks later, or partial/complete regression on ≥1 follow-up MRI 4 weeks later.

Results

In total, 4,051 MRIs from 584 patients were available. This interim analysis included data on 462 patients with similar proportions in the cilengitide and control arm (50.9% and 49.1%). Due to missing MRIs or values, 128 were excluded. Of the remaining 334 patients, 157 (47%) patients showed RANO measurable disease at baseline or nadir (median SPD, 0mm2; interquartile range (IQR) 552.1 (0-552.1). After chemoradiotherapy with or without cilengitide, PPD occurred in 214 patients (64.1%) after a median time of 6.08 months after finishing radiation (IQR 11.4 (2.4-13.8), and 3.65 months after baseline or nadir (IQR 6.4 (2.1-8.5). After follow-up of these 214 patients, treatment-associated changes were diagnosed in 62 (18.6%) and PD was diagnosed in 48 (14.4%). The remaining 104 (31.1%) patients had no further follow-up MRI after PPD, mostly because a clinical decision to call PD was made. In the cilengitide group of 178 patients, 37 (20.8%) patients developed treatment-associated changes, and 23 (12.9%) patients developed PD, whereas in the control group of 156 patients, 25 (16%) patients developed treatment-associated changes, and 25 (16%) patients PD.

Conclusion

With the modified RANO criteria, the rate of treatment-associated changes was low compared to previous studies in newly diagnosed MGMT promoter-methylated glioblastoma. This rate did not change with addition of cilengitide. RANO-recommended radiological follow-up was not always awaited, which reflects clinical practice. Full data will be presented.

Case Report: The Medical and Surgical Management of an Infant With Extreme Prematurity and Fetus-In-Fetu

Fetus-in-fetu (FIF) is a rare congenital anomaly where a parasitic twin is within the body of a host twin. FIF is reported to occur in 1:500,000 live births. Herein, we report the first case of the medical and surgical treatment of a FIF patient who was born with extreme prematurity at 25-weeks gestation. With the multi-disciplinary coordination of neonatology, surgery, and interventional radiology, the patient was able to achieve a window of medical stability 4 weeks after birth. A decision was made at that time to proceed with an intra-abdominal and perineal resection of the FIF. The FIF was successfully resected and the patient was able to recover from the operation, with eventual discharge from the NICU. In conclusion, extreme prematurity and FIF may be amenable to surgical resection and a multi-disciplinary approach is crucial to achieve the desired outcome.

P14.06 Radiomics for the non-invasive determination of the BRAF mutational status in patients with melanoma brain metastases

BACKGROUND

The BRAF V600E mutation is present in approximately 50% of patients with melanoma and is an important prerequisite for a response to targeted therapies such as BRAF inhibitors. In the majority of patients, the BRAF mutational status is based on the analysis of tissue samples from the extracranial primary tumor only. Since the extracranial and intracranial BRAF mutational status may be discrepant, the additional information on the BRAF mutational status of melanoma brain metastases would be of clinical value, e.g., for the prediction of response to targeted therapies. Here, we evaluated the potential of structural MRI radiomics for the determination of the intracranial BRAF mutational status in patients with melanoma brain metastases.

MATERIAL AND METHODS

Fifty-nine patients with melanoma brain metastases from two university hospitals (group 1, 45 patients; group 2, 14 patients) underwent surgery with subsequent genetic analysis of the brain metastases tissue to determine the BRAF mutational status. All patients underwent structural MRI preoperatively. Areas of contrast enhancement were manually segmented and analyzed. Group 1 was used for model training and validation, group 2 for model testing. After image preprocessing, 1,316 radiomics features were extracted using the open-source PyRadiomics package. A test-retest analysis was performed to identify robust features prior to feature selection. Finally, the best performing radiomics model was applied to the test data (group 2). Diagnostic performances were evaluated using receiver operating characteristic (ROC) analyses.

RESULTS

Twenty-two patients (49%) in group 1, and 6 patients (43%) in group 2 had an intrametastatic BRAF V600E mutation. Using a six parameter radiomics signature, a linear support vector machine classifier yielded an average area under the ROC curve (AUC) of 0.87 (accuracy, 85%; sensitivity, 78%; specificity, 91%) for prediction of the BRAF mutational status in the training data (group 1). Finally, the classifier achieved an AUC of 0.85 (accuracy, 86%; sensitivity, 83%; specificity, 88%) in the test data (group 2).

CONCLUSION

The developed radiomics classifier allows a non-invasive prediction of the intracranial BRAF V600E mutational status in patients with melanoma brain metastases and may be of value for treatment decisions.

OS03.3.A Characterization of long-term metabolic changes of irradiated brain metastases using serial dynamic FET PET imaging

BACKGROUND

In the present study, we characterized the long-term metabolic changes of brain metastases irradiated with stereotactic radiosurgery (SRS) by sequential dynamic PET imaging using the radiolabeled amino acid O-(2-[18F]-fluoroethyl)-L-tyrosine (FET). We hypothesized that this approach is of considerable clinical value to diagnose delayed radiation-induced changes.

MATERIAL AND METHODS

From 2010–2021, we retrospectively identified patients with brain metastases from solid extracranial primary tumors who (i) were treated with SRS with or without concurrent immunotherapy using checkpoint inhibitors, (ii) had equivocal or progressive MRI findings after SRS, and (iii) subsequently underwent at least two additional dynamic FET PET scans during follow-up for long-term evaluation. Mean tumor-to-brain ratios (TBR) and the dynamic FET PET parameter time-to-peak were obtained. Diagnostic performances were calculated using receiver operating characteristic curve analyses. Diagnoses were confirmed histologically or clinicoradiologically.

RESULTS

We identified 36 patients with 98 FET PET scans (median number, 3; range, 2–6). Concurrent to SRS, 8 patients (22%) were treated with checkpoint inhibitors. Following SRS, suspicious MRI findings occurred after a median time of 11 months (range, 2–64 months). Subsequently, FET PET scans were acquired over a median period of 13 months (range, 5–60 months). The overall median follow-up time was 26 months (range, 8–101 months). Twenty-one patients (58%) had delayed radiation-induced changes. TBRs calculated from the last available FET PET scan showed the highest accuracy (92%) to identify delayed radiation-induced changes (threshold, 1.95; P&lt;0.001).

CONCLUSION

FET PET has a high diagnostic accuracy for characterizing the long-term changes of irradiated brain metastases.

Mortality trends in neonatal ECMO for pulmonary hypoplasia: A review of the Extracorporeal Life Support Organization database from 1981 to 2016

BACKGROUND

The purpose of this review is to provide ECMO outcome data for medical personnel who counsel families of patients with pulmonary hypoplasia (PH), often secondary to renal abnormalities. We report diagnoses and outcomes associated with PH in neonates that were treated with ECMO over the past 35 years.

METHODS

Retrospective cohort study using the ELSO database for neonates born between 1981 and 2016 with a primary or secondary diagnosis of PH. Five patient groups were created based on ICD-9 codes. Mortality rates were compared and trends over time were investigated.

RESULTS

Thirty-three percent of the 1385 patients survived to discharge. Congenital diaphragmatic hernia (CDH) patients had significantly higher mortality than PH patients secondary to renal dysplasia (p < 0.001). Mortality decreased significantly over time for all groups (p < 0.001). The proportion of patients alive at discharge increased over time for CDH patients (p < 0.001), whereas survival decreased for patients with PH secondary to renal dysplasia (p = 0.012).

CONCLUSIONS

Neonates with PH that require ECMO have high mortality rates, which have generally decreased over the past 35 years; however, mortality for neonates with PH secondary to renal dysplasia continues to increase. We speculate that the apparent rise in mortality for these patients is because of changes in patient selection subsequent to improvements in non-ECMO ventilatory support.

LEVEL OF EVIDENCE

II.

Newborn with Perinatal Naphthalene Toxicity after Maternal Ingestion of Mothballs during Pregnancy

Maternal ingestion of naphthalene-containing mothballs is an uncommon cause of perinatal toxicity. Naphthalene toxicity is associated with methemoglobinemia, hypotension, hemolytic anemia, and hyperbilirubinemia, as well as other hepatic, renal, and respiratory complications. Naphthalene exposure is a common cause of toxicity in older children, but is rarely described in neonates. The neonatal cases described in the literature focus primarily on maternal inhalation as opposed to ingestion. We present a case of perinatal toxicity due to repeated maternal ingestion of naphthalene-containing mothballs during pregnancy. The patient presented with methemoglobinemia, hypotension, hemolytic anemia, and hyperbilirubinemia. Sepsis or pulmonary hypertension were the initial working diagnoses, as the mother did not provide the history of ingestion until after the patient's clinical status worsened. This case highlights the importance of obtaining a thorough maternal history and considering maternal ingestion when the etiology of symptoms is not clear.

P14.32 Spatial discrepancies between FET PET and conventional MRI in patients with newly diagnosed glioblastoma

BACKGROUND

In patients with glioblastoma, the tissue showing contrast enhancement (CE) in MRI is usually the target for resection or radiotherapy. However, the solid tumor mass typically extends beyond the area of CE. Amino acid PET can detect tumor parts that show no CE. We systematically investigated tumor volumes delineated by amino acid PET and MRI in newly diagnosed, untreated glioblastoma patients.

MATERIAL AND METHODS

Preoperatively, 50 patients with subsequently neuropathologically confirmed glioblastoma underwent O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET, fluid-attenuated inversion recovery (FLAIR), and CE MRI. Areas of CE were manually delineated. FET PET tumor volumes were segmented using a tumor-to-brain ratio ≥ 1.6. The percentage of overlapping volumes (OV), as well as Dice and Jaccard spatial similarity coefficients (DSC; JSC), were calculated. FLAIR images were evaluated visually.

RESULTS

In 86% of patients (n = 43), the FET PET tumor volume was significantly larger than the volume of CE (21.5 ± 14.3 mL vs. 9.4 ± 11.3 mL; P < 0.001). Forty patients (80%) showed both an increased uptake of FET and CE. In these 40 patients, the spatial similarity between FET and CE was low (mean DSC, 0.39 ± 0.21; mean JSC, 0.26 ± 0.16). Ten patients (20%) showed no CE, and one of these patients showed no FET uptake. In 10% of patients (n = 5), increased FET uptake was present outside of areas of FLAIR hyperintensity.

CONCLUSION

Our results show that the metabolically active tumor volume delineated by FET PET is significantly larger than tumor volume delineated by CE. The data strongly suggest that the information derived from FET PET should be integrated into the management of newly diagnosed glioblastoma patients.

FUNDING

This work was supported by the Wilhelm-Sander Stiftung, Germany

P14.17 Differentiation of treatment-related changes from tumor progression: A direct comparison between dynamic FET PET and ADC values obtained from DWI MRI

BACKGROUND

Following brain cancer treatment, the capacity of anatomical MRI to differentiate neoplastic tissue from treatment-related changes (e.g., pseudoprogression) is limited. This study compared apparent diffusion coefficients (ADC) obtained by diffusion-weighted MRI (DWI) with static and dynamic parameters of O-(2-[18F]fluoroethyl)-L-tyrosine (FET) PET for the differentiation of treatment-related changes from tumor progression.

MATERIAL AND METHODS

Forty-eight pretreated high-grade glioma patients with anatomical MRI findings suspicious for progression (median time elapsed since last treatment, 16 weeks) were investigated using DWI and dynamic FET PET. Maximum and mean tumor-to-brain ratios (TBRmax, TBRmean) as well as dynamic parameters (time-to-peak and slope values) of FET uptake were calculated. For mean ADC calculation, regions-of-interest analyses were performed on ADC maps calculated from DWI co-registered with the contrast-enhanced MR image. Diagnoses were confirmed neuropathologically (21%) or clinicoradiologically. Diagnostic performance was evaluated using receiver-operating-characteristic analyses or Fisher’s exact test for a combinational approach.

RESULTS

Ten of 48 patients had treatment-related changes (21%). The diagnostic performance of FET PET was significantly higher (threshold for both TBRmax and TBRmean, 1.95; accuracy, 83%; AUC, 0.89±0.05; P<0.001) than that of ADC values (threshold ADC, 1.09x10-3 mm2/s; accuracy, 69%; AUC, 0.73±0.09; P=0.13). The addition of static FET PET parameters to ADC values increased the latter’s accuracy to 89%. The highest accuracy was achieved by combining static and dynamic FET PET parameters (93%).

CONCLUSION

Data suggest that static and dynamic FET PET provide valuable information concerning the differentiation of early treatment-related changes from tumor progression and outperform ADC measurement for this highly relevant clinical question.

P14.29 Prediction of overall survival in patients with malignant glioma using dynamic O-(2-[18F]-fluoroethyl)-L-tyrosine PET

BACKGROUND

Characterization of gliomas according to the revised World Health Organization (WHO) classification of 2016 has gained major importance regarding prognostication. The present study aimed at exploring the prognostic value of dynamic O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET in newly diagnosed and molecularly defined astrocytic high-grade glioma (HGG) of the WHO grades III or IV.

MATERIAL AND METHODS

Before initiation of treatment, dynamic FET PET imaging was performed in patients with newly diagnosed glioblastoma (GBM) and anaplastic astrocytoma (AA). Static FET PET parameters such as maximum and mean tumor/brain ratios (TBRmax/mean), as well as the dynamic FET PET parameters time-to-peak (TTP) and slope, were obtained. The predictive ability of FET PET parameters was evaluated with regard to the overall survival (OS). Using ROC analyses, threshold values for FET PET parameters were obtained. Subsequently, univariate Kaplan-Meier and multivariate Cox regression survival analyses were performed to assess their predictive power for OS.

RESULTS

Sixty patients (45 GBM, 15 AA) of two university centers were retrospectively identified. Patients with a methylated MGMT promoter as well as with an IDH mutation had a significantly longer OS (both P<0.001). Furthermore, ROC analysis revealed in IDH-wildtype HGG (n=45) that a TTP>25 minutes (AUC, 0.90; sensitivity, 90%; specificity, 87%; P<0.001) was highly prognostic for a longer OS (29 vs. 12 months; P<0.001). Besides a complete resection and a methylated MGMT promoter, TTP remained significant in the multivariate survival analysis (P=0.002, P=0.016, and P=0.003, respectively), indicating an independent predictor for OS. In contrast, both TBRmax and TBRmean were not prognostic (AUC, 0.37 and 0.32, respectively).

CONCLUSION

Data suggest that within the subgroup of patients with newly diagnosed and untreated IDH-wildtype GBM and AA, dynamic FET PET additionally allows the identification of patients with an improved OS.

P14.18 Prognostic value of serial dynamic O-(2-[18F]-fluoroethyl)-L-tyrosine PET in patients with non-resectable malignant glioma undergoing chemoradiation

BACKGROUND

A complete resection of high-grade gliomas (HGG) is associated with improved survival, which, however, cannot be achieved in a considerable number of patients. We here evaluated the prognostic value of serial O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET in patients with newly diagnosed, non-resectable astrocytic HGG undergoing chemoradiation with temozolomide.

MATERIAL AND METHODS

Serial dynamic FET PET scans were performed in 18 newly diagnosed patients with molecularly defined, non-resectable HGG at baseline and after chemoradiation (8±3 weeks). Both static (tumor/brain ratios, FET tumor volumes) and dynamic FET PET parameters (time-to-peak, slope), as well as MRI changes according to RANO criteria at first follow-up after chemoradiation (8±3 weeks), were obtained. The predictive ability of FET PET parameters and RANO criteria was evaluated with regard to the progression-free survival (PFS). Using ROC analyses, threshold values for FET PET parameters were obtained. Subsequently, univariate and multivariate survival analyses were performed to assess their predictive power for PFS.

RESULTS

ROC analysis revealed that the mean tumor/brain ratio (AUC, 0.84), FET tumor volume (AUC, 0.89), and slope (AUC, 0.72) at baseline were predictive for a prolonged PFS (9.3 vs. 5.7 months, P=0.05; 10.3 vs. 5.9 months; P=0.03; 13.5 vs. 6.2 months, P=0.02, respectively). Furthermore, FET tumor volume and slope remained significant in the multivariate survival analysis (both P<0.05). In contrast, relative changes of static or dynamic FET PET parameters at follow-up and MRI changes according to RANO criteria were not significant in this albeit small series of patients.

CONCLUSION

Results suggest that before initiation of chemoradiation FET PET parameters at baseline can be used to predict PFS in patients with non-resectable HGG.

Improved feeding tolerance and growth are linked to increased gut microbial community diversity in very-low-birth-weight infants fed mother's own milk compared with donor breast milk

BACKGROUND

Mother's own milk (MOM) is protective against gut microbiota alterations associated with necrotizing enterocolitis (NEC) and feeding intolerance among preterm infants. It is unclear whether this benefit is preserved with donor milk (DM) feeding.

OBJECTIVE

We aimed to compare microbiota development, growth, and feeding tolerance in very-low-birth-weight (VLBW) infants fed an exclusively human milk diet of primarily MOM or DM.

METHODS

One hundred and twenty-five VLBW infants born at Texas Children's Hospital were enrolled and grouped into cohorts based on percentage of MOM and DM in enteral feeds. Feeds were fortified with DM-derived fortifier per unit protocol. Weekly stool samples were collected for 6 wk for microbiota analysis [16S ribosomal RNA (rRNA) sequencing]. A research nurse obtained weekly anthropometrics. Clinical outcomes were compared via Wilcoxon's rank-sum test and Fisher's exact test, as well as multivariate analysis.

RESULTS

The DM cohort (n = 43) received on average 14% mothers' milk compared with 91% for the MOM cohort (n = 74). Diversity of gut microbiota across all time points (n = 546) combined was increased in MOM infants (P < 0.001). By 4 and 6 wk of life, microbiota in MOM infants contained increased abundance of Bifidobacterium (P = 0.02) and Bacteroides (P = 0.04), whereas DM-fed infants had increased abundance of Staphylococcus (P = 0.02). MOM-fed infants experienced a 60% reduction in feeding intolerance (P = 0.03 by multivariate analysis) compared with DM-fed infants. MOM-fed infants had greater weight gain than DM-fed infants.

CONCLUSIONS

Compared with DM-fed infants, MOM-fed infants have increased gut microbial community diversity at the phylum and genus levels by 4 and 6 wk of life, as well as better feeding tolerance. MOM-fed infants had superior growth. The incidence of NEC and other gastrointestinal morbidity is low among VLBW infants fed an exclusively human milk diet including DM-derived fortifier. This trial was registered at clinicaltrials.gov as NCT02573779.

Airway Microbiome and Development of Bronchopulmonary Dysplasia in Preterm Infants: A Systematic Review

OBJECTIVES

To summarize evidence regarding microbial dysbiosis of the airway associated with bronchopulmonary dysplasia (BPD) and to explore heterogeneity among studies.

STUDY DESIGN

We included studies that evaluated the airway microbiome in preterm infants who developed BPD using culture-independent molecular techniques and reported alpha- and beta-diversity metrics and microbial profiles.

RESULTS

The 6 included studies had substantial clinical and methodological heterogeneity. Most studies reported the presence of an airway microbiome early after birth and an evolution in the first weeks of life with increasing bacterial loads. The early airway microbiome was dominated by Staphylococcus and Ureaplasma spp. Two studies reported differences in alpha- and beta- diversity indices in preterm infants with BPD compared with those who did not develop BPD. Increased microbial community turnover, changes in the relative abundance of Proteobacteria and Firmicutes, and decreased Lactobacilli were reported with BPD progression. Most included infants were born by cesarean delivery, and a majority were exposed to postnatal antibiotics. No data regarding feeding human milk or correlations with the development of gut microbiota (gut-lung axis) were available.

CONCLUSIONS

Microbial dysbiosis may be associated with BPD progression and severity, and further study of microbiome optimization in preterm infants at risk for BPD is warranted.

Predictive value of oxygenation index for outcomes in left-sided congenital diaphragmatic hernia

BACKGROUND & OBJECTIVES

Congenital Diaphragmatic Hernia (CDH) is associated with significant morbidity and mortality. This study compares the efficacy of the highest oxygenation index in the first 48 h (HiOI) versus current prenatal indices to predict survival and morbidity.

METHODS

Medical records of 50 prenatally diagnosed, isolated, left-sided CDH patients treated from January 2011 to April 2016 were reviewed. Data abstracted included HiOI, lung to head ratio (LHR), observed to expected total fetal lung volume (O/E TFLV), percent liver herniation (%LH), 6 month survival, respiratory support at discharge, ventilator days and length of stay. Data were analyzed using parametric and nonparametric tests and regression analyses as appropriate.

RESULTS

HiOI was associated with significantly increased LOS (p<0.001), respiratory support at discharge (p<0.001), greater ventilator days (p=0.001) and higher odds of death (p=0.004) with risk of death increasing by 5% for every one-unit increase in OI. HiOI was statistically a better predictor of LOS than O/E TFLV (p=0.007) and %LH (p=0.02).

CONCLUSIONS

In isolated, left-sided CDH patients, HiOI is associated with higher mortality, greater length of stay, more ventilator days and increased respiratory support at discharge. HiOI is a better predictor of length of stay than O/E TFLV and %LH.

TYPE OF STUDY

Retrospective Study LEVEL OF EVIDENCE: II.

Ranid Herpesvirus 3 and Proliferative Dermatitis in Free-Ranging Wild Common Frogs (Rana Temporaria)

Amphibian pathogens are of current interest as contributors to the global decline of amphibians. However, compared with chytrid fungi and ranaviruses, herpesviruses have received relatively little attention. Two ranid herpesviruses have been described: namely, Ranid herpesvirus 1 (RHV1) and Ranid herpesvirus 2 (RHV2). This article describes the discovery and partial characterization of a novel virus tentatively named Ranid herpesvirus 3 (RHV3), a candidate member of the genus Batrachovirus in the family Alloherpesviridae. RHV3 infection in wild common frogs (Rana temporaria) was associated with severe multifocal epidermal hyperplasia, dermal edema, a minor inflammatory response, and variable mucous gland degeneration. Intranuclear inclusions were numerous in the affected epidermis together with unique extracellular aggregates of herpesvirus-like particles. The RHV3-associated skin disease has features similar to those of a condition recognized in European frogs for the last 20 years and whose cause has remained elusive. The genome of RHV3 shares most of the features of the Alloherpesviruses. The characterization of this presumptive pathogen may be of value for amphibian conservation and for a better understanding of the biology of Alloherpesviruses.

Pre-cannulation lung biopsy shortens ECMO course

We describe the clinical course of an infant with respiratory failure who underwent lung biopsy prior to cannulation for undergoing extracorporeal membrane oxygenation (ECMO). Pathology revealed alveolar capillary dysplasia, and ECMO was discontinued. Rapid diagnosis allowed for closure and saved resources. We recommend considering early biopsy in infants with atypical pulmonary hypertension.

Spatial performance in a complex maze is associated with persistent long-term potentiation enhancement in mouse hippocampal slices at early training stages

Long-term potentiation (LTP) and long-term depression (LTD) are principal reflections of synaptic plasticity that have been implicated in learning and memory. We have previously shown that spatial learning in a newly validated complex maze is accompanied by depression of hippocampal CA1 synaptic activity in hippocampal slices of trained mice ("behavioral LTD"). In the present study, we investigated whether behavioral LTD is accompanied by alterations of subsequent LTP induced by high-frequency stimulation (HFS). Moreover, we were interested in the time course of such alterations in relation to training stage. Animals underwent 1, 2, and 8 days of spatial training in the complex maze, respectively. Hippocampal slices were taken 24 h after the last training session. We found a simultaneous decrease of basal synaptic response and increase of HFS induced LTP magnitude compared with slices of untrained animals. Synaptic plasticity was not influenced by repeated running wheel exercise in an additional control group without spatial learning. The mentioned alterations occurred already after day 2 of maze exploration parallel to the most pronounced improvement of behavioral performance but did not change thereafter until day 8 despite further learning progress. They were also found when animals were trained for 2 days and kept at rest for a subsequent 6 days. In conclusion, spatial learning may be reflected by distinct and persistent measurable alterations of synaptic plasticity in hippocampal CA1 neurons at early training stages.