The geographic distribution of stream reaches with potential to support high-quality habitat for salmonids has bearing on the actual status of habitats and populations over broad spatial extents. As part of the Coastal Landscape Analysis and Modeling Study (CLAMS), we examined how salmon-habitat potential was distributed relative to current and future (+100 years) landscape characteristics in the Coastal Province of Oregon, USA. The intrinsic potential to provide high-quality rearing habitat was modeled for juvenile coho salmon (Oncorhynchus kisutch) and juvenile steelhead (O. mykiss) based on stream flow, valley constraint, and stream gradient. Land ownership, use, and cover were summarized for 100-m analysis buffers on either side of stream reaches with high intrinsic potential and in the overall area encompassing the buffers. Past management seems to have concentrated nonindustrial private ownership, agriculture, and developed uses adjacent to reaches with high intrinsic potential for coho salmon. Thus, of the area in coho salmon buffers, 45% is either nonforested or recently logged, but only 10% is in larger-diameter forests. For the area in steelhead buffers, 21% is either non-forested or recently logged while 20% is in larger-diameter forests. Older forests are most extensive on federal lands but are rare on private lands, highlighting the critical role for public lands in near-term salmon conservation. Agriculture and development are projected to remain focused near high-intrinsic-potential reaches for coho salmon, increasing the importance of effectively addressing nonpoint source pollution from these uses. Percentages of larger-diameter forests are expected to increase throughout the province, but the increase will be only half as much in coho salmon buffers as in steelhead buffers. Most of the increase is projected for public lands, where policies emphasize biodiversity protection. Results suggest that widespread recovery of coho salmon is unlikely unless habitat can be improved in high-intrinsic-potential reaches on private lands. Knowing where high-intrinsic-potential stream reaches occur relative to landscape characteristics can help in evaluating the current and future condition of freshwater habitat, explaining differences between species in population status and risk, and assessing the need for and feasibility of restoration.

MRI is emerging as a promising modality for monitoring carotid atherosclerosis. Multiple MR contrast weightings are required for identification of plaque constituents. In this study, eight MR contrast weightings with proven potential for plaque characterization were used to image carotid endarterectomy specimens. A classification technique was developed to create a tissuespecific map by incorporating information from all MR contrast weightings. The classifier was validated by comparison with micro-CT (calcification only) and with matched histological slices registered to MR images using a nonlinear warping algorithm (other components). A pathologist who was blinded to the classifier results manually segmented digitized histological images. Atherosclerosis is a chronic and progressive disease that is characterized by the accumulation of lipids and fibrous tissue within the artery wall (1). Disruption of atherosclerotic plaques at the carotid bifurcation is believed to be the underlying cause of many embolic strokes; furthermore, the histological composition of carotid atheroma is related to a plaque's vulnerability to rupture (2,3). In general, unstable plaques are characterized by a thin, fibrous cap that separates a pool of extracellular lipid and necrosis from the lumen (4). If the integrity of the fibrous cap is compromised, the necrotic core is exposed to the bloodstream and thrombus formation may occur. Several factors may play a role in triggering plaque rupture, including the size and spatial distribution of various plaque components (5); however, the specific plaque components or mechanisms responsible for plaque rupture and/or erosion and subsequent clinical events have yet to be elucidated (4). Further knowledge regarding the explicit features that confer vulnerability to a lesion may come from studies that track changes in plaque composition over time.MR is a promising noninvasive technique for characterizing atherosclerotic plaque composition. Because of the complexity and variability of atherosclerotic lesions, it is necessary to employ several MR contrast weightings to adequately discriminate between plaque constituents. Ex vivo studies have demonstrated that T 2 -weighted contrast alone is inadequate for measuring the size of the lipid core (6), but a combination of proton density, partial T 2 , T 2 , and diffusion-weighted spin-echo sequences can provide a more accurate assessment of plaque microstructure (7). Multicontrast-weighted MR has also been shown to be necessary for characterizing plaque in vivo. In a series of patients undergoing carotid endarterectomy, no single MR contrast weighting was able to identify lipid-rich necrotic cores and intraplaque hemorrhage; rather, a review of proton density, T 1 , T 2 , and time-of-flight (TOF) contrast weightings was required (8). In a subsequent investigation, these same four contrast weightings provided enough information to successfully classify carotid plaques according to a modified American Heart Association classification scheme (9). These stu...

Purpose To develop and evaluate a multiphasic contrast-enhanced MRI method called DIfferential Sub-sampling with Cartesian Ordering (DISCO) for abdominal imaging. Materials and Methods A three-dimensional, variable density pseudo-random k-space segmentation scheme was developed and combined with a Dixon-based fat-water separation algorithm to generate high temporal resolution images with robust fat suppression and without compromise in spatial resolution or coverage. With IRB approval and informed consent, 11 consecutive patients referred for abdominal MRI at 3T were imaged with both DISCO and a routine clinical 3D SPGR-Dixon (LAVA FLEX) sequence. All images were graded by two radiologists using quality of fat suppression, severity of artifacts, and overall image quality as scoring criteria. For assessment of arterial phase capture efficiency, the number of temporal phases with angiographic phase and hepatic arterial phase was recorded. Results There were no significant differences in quality of fat suppression, artifact severity or overall image quality between DISCO and LAVA FLEX images (p > 0.05, Wilcoxon signed rank test). The angiographic and arterial phases were captured in all 11 patients scanned using the DISCO acquisition (mean number of phases were 2 and 3 respectively). Conclusion DISCO effectively captures the fast dynamics of abdominal pathology such as hyperenhancing hepatic lesions with a high spatio-temporal resolution. Typically, 1.1×1.5×3 mm spatial resolution over 60 slices was achieved with a temporal resolution of 4–5 seconds.

Image quality metrics (IQMs) such as root mean square error (RMSE) and structural similarity index (SSIM) are commonly used in the evaluation and optimization of accelerated magnetic resonance imaging (MRI) acquisition and reconstruction strategies. However, it is unknown how well these indices relate to a radiologist's perception of diagnostic image quality. In this study, we compare the image quality scores of five radiologists with the RMSE, SSIM, and other potentially useful IQMs: peak signal to noise ratio (PSNR) multi-scale SSIM (MSSSIM), information-weighted SSIM (IWSSIM), gradient magnitude similarity deviation (GMSD), feature similarity index (FSIM), high dynamic range visible difference predictor (HDRVDP), noise quality metric (NQM), and visual information fidelity (VIF). The comparison uses a database of MR images of the brain and abdomen that have been retrospectively degraded by noise, blurring, undersampling, motion, and wavelet compression for a total of 414 degraded images. A total of 1017 subjective scores were assigned by five radiologists. IQM performance was measured via the Spearman rank order correlation coefficient (SROCC) and statistically significant differences in the residuals of the IQM scores and radiologists' scores were tested. When considering SROCC calculated from combining scores from all radiologists across all image types, RMSE and SSIM had lower SROCC than six of the other IQMs included in the study (VIF, FSIM, NQM, GMSD, IWSSIM, and HDRVDP).In no case did SSIM have a higher SROCC or significantly smaller residuals than RMSE. These results should be considered when choosing an IQM in future imaging studies.

Managers, regulators, and researchers of aquatic ecosystems are increasingly pressed to consider large areas. However, accurate stream maps with geo-referenced attributes are uncommon over relevant spatial extents. Field inventories provide high-quality data, particularly for habitat characteristics at fine spatial resolutions (e.g., large wood), but are costly and so cover relatively small areas. Recent availability of regional digital data and Geographic Information Systems software has advanced capabilities to delineate stream networks and estimate coarse-resolution hydrogeomorphic attributes (e.g., gradient). A spatially comprehensive coverage results, but types of modeled outputs may be limited and their accuracy is typically unknown. Capitalizing on strengths in both field and regional digital data, we modeled a synthetic stream network and a variety of hydrogeomorphic attributes for the Oregon Coastal Province. The synthetic network, encompassing 96,000 km of stream, was derived from digital elevation data. We used high-resolution but spatially restricted data from field inventories and streamflow gauges to evaluate, calibrate, and interpret hydrogeomorphic attributes modeled from digital elevation and precipitation data. The attributes we chose to model (drainage area, mean annual precipitation, mean annual flow, probability of perennial flow, channel gradient, active-channel width and depth, valley-floor width, valley-width index, and valley constraint) have demonstrated value for stream research and management. For most of these attributes, field-measured, and modeled values were highly correlated, yielding confidence in the modeled outputs. The modeled stream network and attributes have been used for a variety of purposes, including mapping riparian areas, identifying headwater streams likely to transport debris flows, and characterizing the potential of streams to provide high-quality habitat for salmonids. Our framework and models can be adapted and applied to areas where the necessary field and digital data exist or can be obtained.

IMPORTANCE Chemoradiotherapy (CRT), followed by surgery, is the recommended approach for stage II and III rectal cancer. While CRT decreases the risk of local recurrence, it does not improve survival and leads to poorer functional outcomes than surgery alone. Therefore, new approaches to better select patients for CRT are important. OBJECTIVE To conduct a phase 2 study to evaluate the safety and feasibility of using magnetic resonance imaging (MRI) criteria to select patients with "good prognosis" rectal tumors for primary surgery. DESIGN, SETTING, AND PARTICIPANTS Prospective nonrandomized phase 2 study at 12 high-volume colorectal surgery centers across Canada. From September 30, 2014, to October 21, 2016, a total of 82 patients were recruited for the study. Participants were patients newly diagnosed as having rectal cancer with MRI-predicted good prognosis rectal cancer. The MRI criteria for good prognosis tumors included distance to the mesorectal fascia greater than 1 mm; definite T2, T2/early T3, or definite T3 with less than 5 mm of extramural depth of invasion; and absent or equivocal extramural venous invasion. INTERVENTIONS Patients with rectal cancer with MRI-predicted good prognosis tumors underwent primary surgery. MAIN OUTCOMES AND MEASURES The primary outcome was the proportion of patients with a positive circumferential resection margin (CRM) rate. Assuming a 10% baseline probability of a positive CRM, a sample size of 75 was estimated to yield a 95% CI of ±6.7%. RESULTS Eighty-two patients (74% male) participated in the study. The median age at the time of surgery was 66 years (range, 37-89 years). Based on MRI, most tumors were midrectal (65% [n = 53]), T2/early T3 (60% [n = 49]), with no suspicious lymph nodes (63% [n = 52]). On final pathology, 91% (n = 75) of tumors were T2 or greater, 29% (n = 24) were node positive, and 59% (n = 48) were stage II or III. The positive CRM rate was 4 of 82 (4.9%; 95% CI, 0.2%-9.6%). CONCLUSIONS AND RELEVANCE The use of MRI criteria to select patients with good prognosis rectal cancer for primary surgery results in a low rate of positive CRM and suggests that CRT may not be necessary for all patients with stage II and III rectal cancer.

Background and Purpose-MRI may be used for noninvasive assessment of atherosclerotic lesions; however, MRI evaluation of plaque composition requires validation against an accepted reference standard, such as the American Heart Association (AHA) lesion grade, defined by histopathological examination. Methods-Forty-eight carotid endarterectomy specimen cross-sections had AHA lesion grade determined histopathologically and were concurrently imaged using combinations of 8 MRI contrast weightings in vitro. A maximum likelihood classification algorithm generated MRI "maps" of plaque components, and an AHA lesion grade was assigned correspondingly. Additional analyses compared classification accuracy obtained with a commonly used set of magnetic resonance contrast weightings [proton density (PDw), T1 (T1w), and partial T2 (T2w)] to accuracy obtained with the combination of PDw, T1w, and diffusion-weighted (Dw) contrast. Results-For the 8-contrast combination, the sensitivities for fibrous tissue, necrotic core, calcification, and hemorrhage detection were 83%, 67%, 86%, and 77%, respectively. The corresponding specificities were 81%, 78%, 99%, and 97%. Good agreement (79%) between magnetic resonance and histopathology for AHA classification was achieved. For the PDw, T1w, and Dw combination, the overall classification accuracy was insignificantly different at 78%, whereas the overall classification accuracy using PDw, T1w, and partial T2w contrast weightings was significantly lower at 67%. Conclusions-This

Thirty-meter digital elevation models (DEMS] (FEMAT, 19931, we are using these databases in the aquatic component of CLAMS to assemble and apply watershed condition indices and to model instream habitat structure from upslope and streamside attributes (CLAMS, 2002). The value of these indices and models relies heavily on the quality and consistency of the foundation data layers u s~d in their consimction.Some of h e foundational data can be derived from digital elevation models t n~~s l ,i .e., slope, elevation, aspect, channel gradient, hydrologic unit (XI) boundaries (FGDG, 2002), and stream traces (Jenson and Domingue, 1988;Jenson, 1991;Moore et al., 1991; Quinn et al., 1991;Tarboton et al., 1991;Band, 1993;Wang and Yin, 1998). These DEM-generated products have many benefits for broad-scale aquatic analyses. For example, streams created from DEMs are precisely registered to (Jenson and Domingue, 1988;Jenson, 1991), which improves the quality of stream-associated topographic information, such as channel gradient and valley floor width. Furthermore, streams created from DEMs always appear as single lines, rather than as braided channels or double-bank streams, and a single line represents water bodies such as lakes and reservoirs. Thus, it is easier to calculate stream order and route stream networks; the latter is necessary prior to georeferencing stream-associated data.We evaluated the usefulness of DEM data for our specific applications throughout the range of landscape characteristics found in our study area, following the recommendation of many authors that DEM evaluations need to be contextual (Walsh et al., 1987;Weih and Smith, 1990;Shearer, 1991;Carter, 1992, Robinson, 1994Zhang and Montgomery, 1994). Given that DEM resolution has been demonstrated to affect the accuracy of landform characterization and drainage networks (e.g., Elsheikh and Guercio, 1997;Thieken et al., 1999;Zhang et al., 1999;McMaster, 2002), we wanted to evaluate advantages for aquatic analyses of employing 10-meter drainageenforced DEMS (DE-DEMS) (Osborn et al., 2001) rather than the more widely available 30-meter DEMs. Specifically, results from 10-meter DE-DEMs and 30-meter DEMs (Level 1 or 2) were compared for deriving (1) a consistent density, positionally accurate, single-line stream layer that corresponded to the topography; (2) hydrologic units delineated at approximately the field hydrologic unit (HU) level; and (3) a representation of topography to calculate slope. The 10-meter DE-DEMS we used have better horizontal and vertical resolution and were produced with a more consistent process (i.e., by the same contractor and specifications; Averstar Geospatial Services, now Titan Corp.') than were the 30-meter DEMS. DEM Data --Concerns about the vertical and horizontal resolution and inconsistent quality of the 30-meter DEMs prompted preliminary assessment of these data for aquatic analyses. Although the U.S. Geological Survey (USGS) has improved its methods to generate DEMS, some of the 30-meter DEMS in the study ...