Comparison of image quality and diagnostic efficacy of routine clinical lumbar spine imaging at 0.55T and 1.5/3T.

PURPOSE: To compare image quality, assess inter-reader variability, and evaluate the diagnostic efficacy of routine clinical lumbar spine sequences at 0.55T compared with those collected at 1.5/3T to assess common spine pathology. METHODS: 665 image series across 70 studies, collected at 0.55T and 1.5/3T, were assessed by two neuroradiology fellows for overall imaging quality (OIQ), artifacts, and accurate visualization of anatomical features (intervertebral discs, neural foramina, spinal cord, bone marrow, and conus / cauda equina nerve roots) using a 4-point Likert scale (1 = non-diagnostic to 4 = excellent). For the 0.55T scans, the most appropriate diagnosis(es) from a picklist of common spine pathologies was selected. The mean ± SD of all scores for all features for each sequence and reader at 0.55T and 1.5/3T were calculated. Paired t-tests (p ≤ 0.05) were used to compare ratings between field strengths. The inter-reader agreement was calculated using linear-weighted Cohen's Kappa coefficient (p ≤ 0.05). Unpaired VCG analysis for OIQ was additionally employed to represent differences between 0.55T and 1.5/3T (95 % CI). RESULTS: All sequences at 0.55T were rated as acceptable (≥2) for diagnostic use by both readers despite significantly lower scores for some compared to those at 1.5/3T. While there was low inter-reader agreement on individual scores, the agreement on the diagnosis was high, demonstrating the potential of this system for detecting routine spine pathology. CONCLUSIONS: Clinical lumbar spine imaging at 0.55T produces diagnostic-quality images demonstrating the feasibility of its use in diagnosing spinal pathology, including osteomyelitis/discitis, post-surgical changes with complications, and metastatic disease.

Gold nanoshells for prostate cancer treatment: evidence for deposition in abdominal organs.

PURPOSE: Gold-silica nanoshell therapy [AuroShells with subsequent focal laser therapy (AuroLase)] is an emerging targeted treatment modality for prostate cancer. We reviewed pre- and post-treatment unenhanced CT imaging to assess for retained gold-silica nanoshells in the abdomen and pelvis. METHODS: This single-institution retrospective study identified patients in the AuroLase pilot who underwent pre- and post-treatment unenhanced abdominopelvic CT. The attenuation, before and after gold-silica nanoshell administration, of the liver, spleen, pancreas, kidneys, prostate, blood pool, paraspinal musculature, and abnormal lymph nodes were manually measured by two readers. After inter-reader agreement was calculated using intraclass correlation (ICC), a permutation test was used to assess pre- and post-therapy attenuation differences. RESULTS: Four patients met the inclusion criteria. Mean age was 72.3 ± 5.9 years. Median time interval between pre-treatment CT and treatment, and between treatment and post-treatment CT, was 232 days and 236.5 days, respectively. The two readers' attenuation measurements had very high agreement (ICC = 0.99, p < 0.001). The highest differences in organ attenuation between pre- and post-therapy scans were seen in all four patients in the liver and spleen (liver increased by an average of 28.9 HU, p = 0.010; spleen increased by an average of 63.7 HU, p = 0.012). A single measured lymph node increased by an average of 58.9 HU. In the remainder of the measured sites, the change in attenuation from pre- to post-therapy scans ranged from -0.1 to 3.8 HU (p > 0.05). CONCLUSION: Increased attenuation of liver and spleen at CT can be an expected finding in patients who have received gold-silica nanoshell therapy.

Clinical Outcomes after Median Arcuate Ligament Release in Patients Responsive to Celiac Plexus Block.

PURPOSE: To determine if symptom relief with celiac plexus block (CPB) is associated with favorable clinical outcomes after median arcuate ligament release (MALR) surgery. MATERIALS AND METHODS: A retrospective review was performed from January 2000 to December 2021. Fifty-seven patients (42 women, 15 men; mean age, 43 years [range, 18-84 years]) with clinical and radiographic features suggestive of median arcuate ligament syndrome (MALS) underwent computed tomography (CT)-guided percutaneous CPB for suspected MALS. Clinical outcomes of CPB and MALR surgery were correlated. Adverse events were classified according to the Society of Interventional Radiology (SIR) guidelines. RESULTS: CT-guided percutaneous CPB was successfully performed in all 57 (100%) patients with suspected MALS. A cohort of 38 (67%) patients showed clinical improvement with CPB. A subset of 28 (74%) patients in this group subsequently underwent open MALR surgery; 27 (96%) responders to CPB showed favorable clinical outcomes with surgery. There was 1 (4%) CPB-related mild adverse event. There were no moderate, severe, or life-threatening adverse events. CONCLUSIONS: Patients who responded to CPB were selected to undergo surgery, and 96% of them improved after surgery.

DIMPLE: AN R PACKAGE TO QUANTIFY, VISUALIZE, AND MODEL SPATIAL CELLULAR INTERACTIONS FROM MULTIPLEX IMAGING WITH DISTANCE MATRICES.

The tumor microenvironment (TME) is a complex ecosystem containing tumor cells, other surrounding cells, blood vessels, and extracellular matrix. Recent advances in multiplexed imaging technologies allow researchers to map several cellular markers in the TME at the single cell level while preserving their spatial locations. Evidence is mounting that cellular interactions in the TME can promote or inhibit tumor development and contribute to drug resistance. Current statistical approaches to quantify cell-cell interactions do not readily scale to the outputs of new imaging technologies which can distinguish many unique cell phenotypes in one image. We propose a scalable analytical framework and accompanying R package, DIMPLE, to quantify, visualize, and model cell-cell interactions in the TME. In application of DIMPLE to publicly available MI data, we uncover statistically significant associations between image-level measures of cell-cell interactions and patient-level covariates.

A novel Bayesian functional spatial partitioning method with application to prostate cancer lesion detection using MRI.

Spatial partitioning methods correct for nonstationarity in spatially related data by partitioning the space into regions of local stationarity. Existing spatial partitioning methods can only estimate linear partitioning boundaries. This is inadequate for detecting an arbitrarily shaped anomalous spatial region within a larger area. We propose a novel Bayesian functional spatial partitioning (BFSP) algorithm, which estimates closed curves that act as partitioning boundaries around anomalous regions of data with a distinct distribution or spatial process. Our method utilizes transitions between a fixed Cartesian and moving polar coordinate system to model the smooth boundary curves using functional estimation tools. Using adaptive Metropolis-Hastings, the BFSP algorithm simultaneously estimates the partitioning boundary and the parameters of the spatial distributions within each region. Through simulation we show that our method is robust to shape of the target zone and region-specific spatial processes. We illustrate our method through the detection of prostate cancer lesions using magnetic resonance imaging.

Ultrasound appearance of regenerative peripheral nerve interface with clinical correlation.

OBJECTIVE: To describe the ultrasound (US) appearance of regenerative peripheral nerve interfaces (RPNIs) in humans, and correlate clinically and with histologic findings from rat RPNI. MATERIALS AND METHODS: Patients (≥ 18 years) who had undergone RPNI surgery within our institution between the dates of 3/2018 and 9/2019 were reviewed. A total of 21 patients (15 male, 6 female, age 21-82 years) with technically adequate US studies of RPNIs were reviewed. Clinical notes were reviewed for the presence of persistent pain after RPNI surgery. Histologic specimens of RPNIs in a rat model from prior studies were compared with the US findings noted in this study. RESULTS: There was a variable appearance to the RPNIs including focal changes involving the distal nerve, nerve-muscle graft junction, and area of the distal sutures. The muscle grafts varied in thickness with accompanying variable echogenic changes. No interval change was noted on follow-up US studies. Diffuse hypoechoic swelling with loss of the fascicular structure of the nerve within the RPNI and focal hypoechoic changes at the nerve-muscle graft junction were associated with clinical outcomes. US findings corresponded to histologic findings in the rat RPNI. CONCLUSION: Ultrasound imaging can demonstrate various morphologic changes involving the nerve, muscle, and interface between these two biological components of RPNIs. These changes correspond to expected degenerative and regenerative processes following nerve resection and muscle reinnervation and should not be misconstrued as pathologic in all cases. N5 and N1 morphologic type changes of the RPNI were found to be associated with symptoms.