Study protocol for a pilot clinical trial to understand neural mechanisms of response to a psychological treatment for pain and anxiety in pediatric functional abdominal pain disorders (FAPD)

BACKGROUND

Functional abdominal pain disorders (FAPD) are the most common chronic pain conditions of childhood and are made worse by co-occurring anxiety. Our research team found that the Aim to Decrease Pain and Anxiety Treatment (ADAPT), a six-session coping skills program using cognitive behavioral therapy strategies, was effective in improving pain-related symptoms and anxiety symptoms compared to standard care. In follow-up, this current randomized clinical trial (RCT) aims to test potential neural mechanisms underlying the effect of ADAPT. Specifically, this two-arm RCT will explore changes in amygdalar functional connectivity (primary outcome) following the ADAPT protocol during the water loading symptom provocation task (WL-SPT). Secondary (e.g., changes in regional cerebral blood flow via pulsed arterial spin labeling MRI) and exploratory (e.g., the association between the changes in functional connectivity and clinical symptoms) outcomes will also be investigated.

METHODS

We will include patients ages 11 to 16 years presenting to outpatient pediatric gastroenterology care at a midwestern children's hospital with a diagnosis of FAPD plus evidence of clinical anxiety based on a validated screening tool (the Generalized Anxiety Disorder-7 [GAD-7] measure). Eligible participants will undergo baseline neuroimaging involving the WL-SPT, and assessment of self-reported pain, anxiety, and additional symptoms, prior to being randomized to a six-week remotely delivered ADAPT program plus standard medical care or standard medical care alone (waitlist). Thereafter, subjects will complete a post assessment neuroimaging visit similar in nature to their first visit.

CONCLUSIONS

This small scale RCT aims to increase understanding of potential neural mechanisms of response to ADAPT.

TRIAL REGISTRATION

ClinicalTrials.gov registration: NCT03518216.

Abstract TMP95: Infarct Growth During Inter-facility Transfer In An Integrated Stroke Network

Background: Perfusion imaging is used to determine eligibility for mechanical thrombectomy (MT) in patients presenting with large vessel occlusion (LVO) in acute ischemic stroke. The utility of CT perfusion (CTP) imaging in spoke hospitals remains controversial. The aim of the study was to compare the imaging parameters, functional and safety outcomes in patients selected for MT based on CTP availability in regional hospitals.

Methods: Consecutive adult patients treated for LVO after initially presenting to regional spokes between Jan 2021 to Dec 2021 were included in the analysis. Our standard Acute Stroke Imaging Protocol included CT/CT angiogram. CT perfusion was added to the protocol in April 2021. Demographics, NIHSS, imaging metrics (ASPECTS, CTA collateral score, reperfusion (mTICI 2b/3) rates), hemorrhage (per ECASS III) and functional outcomes (modified Rankin Scale of 0-2 at 90 days) were compared between patients who did vs. did not undergo CTP at regional. Core infarct volume growth and rate (ml/min) was assessed for patients with CTP data both at the regional and at the Comprehensive Stroke Center (CSC).

Results: A total of 29 patients met inclusion during the study period. Of these, 14 patients were transferred to CSC for possible MT without CTP at the regional facility and 15 were transferred with CTP at regional. Age (p=0.44), NIHSS (p=0.08) and onset-to-regional facility arrival time (p=0.54) were similar in both groups. For all patients, repeat imaging at the CSC showed significantly decreased ASPECTS (p=0.002) but stable CTA collateral score (p=0.94). For patients who underwent CTP both at the regional facility and CSC, median core infarct volume grew significantly (0[0, 7] ml vs. 7 [0, 14] ml, p=0.022), with a median growth rate of 0 [0, 0.07] ml/min. No patients were excluded from thrombectomy due to core infarct growth. Rates of successful reperfusion (p=0.83) and hemorrhagic transformation (p=0.49) did not differ significantly between the groups. Rates of mRS 0-2 were similar in both groups (p=0.85).

Conclusion: Our study suggests that core infarct grows during interfacility transfers without an impact on selection for thrombectomy and outcomes. A larger study is needed to assess the need for repeating perfusion imaging at CSC.

Abstract TP26: System-wide Implementation Of Computed Tomography Perfusion (CTP) Imaging

Background: Mechanical thrombectomy (MT) is effective for reducing morbidity in patients presenting within 24 hours of symptom onset with large vessel occlusion (LVO). Perfusion imaging is helpful in selecting patients in this extended time window. We report our experience of implementing CTP imaging in all our spokes and its impact on quality metrics and outcomes.

Methods: Acute Stroke Imaging Protocol was updated to include CTP in addition to CT and CTA for all suspected stroke patients presenting within 24 hours of symptoms in April 2021 processed by RAPID AI (iSchema View inc, Menlo Park, CA, USA). Consecutive patients aged ≥18 years with suspected stroke presenting to regional spokes between Jan 2021 to Dec 2021 were included in the analysis. Demographics, NIHSS, quality metrics at regional facility (Door-to-thrombolysis, door-in-door-out times) and Comprehensive Stroke Center-CSC (door-to-arterial access, reperfusion rates (TICI IIb/III), hemorrhagic transformation) and functional outcomes (modified Rankin Scale, mRS) at 90 days were compared between the groups.

Results: CTP studies were performed on 1113 patients between April 2021 and December 2021. RAPID AI processing identified LVO in 203 (18.7%) patients, of which 29 (14%) patients were included in this analysis; 14 patients were transferred to CSC for possible MT without CTP at regional facility and 15 were transferred with CTP at regional. Age (p=0.44), NIHSS (p=0.08) and onset-arrival time (p=0.54) were similar in both groups at the regional facility. Door to thrombolysis (p=0.13) and door-in-door-out (p=0.17) times were similar in both groups at the regional facility. CSC metrics of door-to-arterial access times (p=0.84), reperfusion (TICI IIB/III) (p=0.83) and hemorrhagic transformation (p=0.49) rates were similar between groups. 90 day good functional outcomes (mRS 0-2) were similar in patients undergoing thrombectomy (p=0.86).

Conclusion: Our study suggests that AI supported perfusion imaging is feasible in a large stroke network and does not appear to have a significant impact on process times, quality metrics and outcomes. A larger study would need to be conducted to validate the observed results.

Abstract WP2: Tissue Based Selection for Large Vessel Occlusion Thrombectomy Leads to Similar Functional Outcomes in Conventional (0-6 Hours) and Extended (>6 Hours) Window

Background: Recent trials have shown benefit of thrombectomy in carefully selected patients in the extended (>6 hours) window. However, it is not clear if the outcomes differ from those undergoing thrombectomy in the conventional (0-6 hours) window. We sought to evaluate if time to treatment modifies the effect of endovascular reperfusion in stroke patients with evidence of salvageable tissue on CT perfusion (CTP).

Methods: We retrospectively analyzed data of consecutive patients who underwent thrombectomy in a single center cohort. Demographics, comorbidities, National Institute of Health Stroke Scale (NIHSS), vessel occlusion location, onset to skin puncture time, core infarct volume on initial CTP, recanalization (mTICI IIb/III) rates, final infarct volume and modified rankin scale (mRS) at 90 days were compared between patients who underwent thrombectomy in conventional (0-6 hours) and extended (>6 hour) window.

Results: 119 patients were studied of which 55% were female. Univariate analysis showed that the groups (Conventional vs. Extended) were balanced for age (p=0.37), NIHSS (p=0.35), vessel occlusion location (p=0.51), initial core infarct volume (p=0.64) and recanalization (mTICI IIb/III) rates (p=0.55). Final infarct volume (p=0.18) and favorable outcome (mRS 0-2) at 90 days (p=0.65) were similar. Shift analysis did not reveal any significant difference in 90 day outcome (p=0.34). (Figure) After adjustment; age (p=0.004) and final infarct volume (p<0.001) were predictive of favorable outcome.

Conclusion: Tissue based selection with CTP for thrombectomy in large vessel occlusion stroke is independent of onset time for favorable functional outcome.

An approach to comparing accuracies of two FLAIR MR sequences in the detection of multiple sclerosis lesions in the brain in the absence of gold standard

RATIONALE AND OBJECTIVES

The purpose of this study was to present a new methodology to compare accuracies of two imaging fluid attenuated inversion recovery (FLAIR) magnetic resonance sequences in detection of multiple sclerosis (MS) lesions in the brain in the absence of ground truth, and to determine whether the two sequences, which differed only in echo time (TE), have the same accuracy.

MATERIALS AND METHODS

We acquired FLAIR images at TE(1) = 90 ms and TE(2) = 155 ms from 46 patients with MS (24-69 years old, mean 45.8, 15 males) and 11 healthy volunteers (23-54 years old, mean 37.1, 6 males). Seven experienced neuroradiologists segmented lesions manually on randomly presented corresponding TE(1) and TE(2) images. For every image pair, a "surrogate ground truth" for each TE was generated by applying probability thresholds, ranging from 0.3 to 0.5, to the weighted average of experts' segmentations. Jackknife alternative free-response receiver operating characteristic analysis was used to compare experts' performance on TE(1) and TE(2) images, using successively the TE(1)- and TE(2)-based ground truths.

RESULTS

Supratentorially, there were significant differences in relative accuracy between the two sequences, ranging from 8.4% to 12.1%. In addition, we found a higher ratio of false positives to true positives for the TE(2) sequence using the TE(2) ground truth, compared to the TE(1) equivalent. Infratentorially, differences in the relative accuracy did not reach statistical significance.

CONCLUSION

The presented methodology may be useful in assessing the value of new clinical imaging protocols or techniques in the context of replacing existing ones, when the absolute ground truth is not available, and in determining changes in disease progression in follow-up studies. Our results suggest that the sequence with shorter TE should be preferred because it generates relatively fewer false positives. The finding is consistent with results of previous computer simulation studies.