Patients may present to the hospital at various times after an ischemic stroke. Many present weeks after a neurologic deficit has occurred, as is often the case with elderly patients and those in a nursing home. The ability to determine the age of an ischemic stroke provides useful clinical information for the patient, his or her family, and the medical team. Many times, perfusion imaging is not performed, and pulse sequence-specific magnetic resonance (MR) imaging findings may help determine the age of the infarct. The findings seen at apparent diffusion coefficient mapping and diffusion-weighted, fluid-attenuated inversion recovery (FLAIR) and unenhanced and contrast material-enhanced T1- and T2-weighted gradient-echo and susceptibility-weighted MR imaging may help determine the relative age of a cerebral infarct. Strokes may be classified and dated as early hyperacute, late hyperacute, acute, subacute, or chronic. Recent data indicate that in many patients with restricted diffusion and no change on FLAIR images, it is more likely than was initially thought that the stroke is less than 6 hours old. The time window to administer intravenous tissue plasminogen activator is currently 4.5 hours from the time when the patient was last seen to be normal, and for anterior circulation strokes, the time window for administering intraarterial tissue plasminogen activator is 6 hours from when the patient was last seen to be normal. For this reason, accurate dating is important in patients with ischemic stroke.

SERP-1 is a myxoma virus-encoded serpin, secreted from infected cells, that is required for virulence and has anti-inflammatory activity. We report that purified recombinant SERP-1 forms SDS-stable complexes with urokinase-type plasminogen activator (uPA), tissuetype plasminogen activator (tPA), plasmin, thrombin, and factor Xa. N-terminal sequencing confirmed Arg 319 -Asn 320 as the site of reaction. Mutation of these residues to Ala-Ala abolished inhibitory activity but had no effect on the specific cleavage at Thr 315 -Leu 316 seen with elastase and with cathepsin G. Kinetic analysis of the reactions with uPA, tPA, plasmin, thrombin, Xa, and C1s showed second-order rate constants to vary over 3 logs, from k inh ‫؍‬ 3 ؋ 10 5 M ؊1 s ؊1 with thrombin to ϳ600 M ؊1 s ؊1with C1s, while steady-state inhibition constants ranged from K I ‫؍‬ 10 pM with thrombin to ϳ100 nM with C1s. Stoichiometries of inhibition varied between SI ‫؍‬ 1.4 ؎ 0.1 for uPA to SI ‫؍‬ 13 ؎ 3 for thrombin. Analysis of the variations in inhibition kinetics shows that when serpins act at low concentrations, comparable with the target protease or with K I (as appears likely for SERP-1 in vivo), inhibitory specificity becomes less dominated by k inh and is increasingly dependent on partitioning within the branched reaction mechanism and on the lifetime of the inhibited complex.

BACKGROUND The 2016 World Health Organization Classification of Tumors of the Central Nervous System incorporates the use of molecular information into the classification of brain tumors, including grade II and III gliomas, providing new prognostic information that cannot be delineated based on histopathology alone. We hypothesized that these genomic subgroups may also have distinct imaging features. METHODS A retrospective single institution study was performed on 40 patients with pathologically proven infiltrating WHO grade II/III gliomas with a pre-treatment MRI and molecular data on IDH, chromosomes 1p/19q and ATRX status. Two blinded Neuroradiologists qualitatively assessed MR features. The relationship between each parameter and molecular subgroup (IDH-wildtype; IDH-mutant-1p/19q codeleted-ATRX intact; IDH-mutant-1p/19q intact-ATRX loss) was evaluated with Fisher’s exact test. Progression free survival (PFS) was also analyzed. RESULTS A border that could not be defined on FLAIR was most characteristic of IDH-wildtype tumors, whereas IDH-mutant tumors demonstrated either well-defined or slightly ill-defined borders (p = 0.019). Degree of contrast enhancement and presence of restricted diffusion did not distinguish molecular subgroups. Frontal lobe predominance was associated with IDH-mutant tumors (p = 0.006). The IDH- wildtype subgroup had significantly shorter PFS than the IDH-mutant groups (p < 0.001). No differences in PFS were present when separating by tumor grade. CONCLUSIONS FLAIR border patterns and tumor location were associated with distinct molecular subgroups of grade II/III gliomas. These imaging features may provide fundamental prognostic and predictive information at time of initial diagnostic imaging.

Trigeminal neuralgia (TN) is a debilitating but treatable disease. Classic TN has referable vascular compression of the trigeminal nerve, but rarely secondary sources of anatomic compression will present, including vascular malformations, aneurysms, or tumors. Understanding the etiology of the patients’ symptoms leads to targeted treatment. Three patients presented with symptoms consistent with TN: shooting, paroxysmal pains in the distribution of the trigeminal nerve. However, imaging revealed no vascular conflict at the root entry zone of the trigeminal nerve. Instead, on the affected side Meckel’s cave was absent. No other compressive mass lesion was identified. In all three cases, patients were offered both Gamma Knife Radiosurgery and surgical decompression of Meckel’s cave. All 3 patients elected to proceed with stereotactic radiation and reported improvement in pain. Many cases of classic TN can be explained by neurovascular conflict at the trigeminal root entry zone, but secondary sources of compression or restriction along the nerve can result in similar symptomology. In this case series, an absent or hypoplastic ipsilateral Meckel’s cave may have produced symptoms consistent with TN. Imaging with fine cuts through Meckel’s cave is an important diagnostic tool.

Compared with the conventional volume score, multi-detector row CT-derived mineral mass is a less biased and more precise measurement of the mineral content of nonmoving ex vivo CEA specimens. Mineral mass and modified Agatston score are more reproducible than conventional volume and Agatston scores.

Post-treatment radiation and chemotherapy of malignant primary glial neoplasms present a wide spectrum of tumor appearances and treatment-related entities. Radiologic findings of these post-treatment effects overlap, making it difficult to distinguish treatment response and failure. The purposes of this article are to illustrate and contrast the imaging appearances of recurrent tumor from necrosis and to discuss other radiologic effects of cancer treatments. It is critical for radiologists to recognize these treatment-related effects to help direct clinical management.

IMPORTANCE Accurately characterizing nasal septal deviations is valuable for surgical planning, classifying nasal septal deviations, providing a means to accurately perform outcomes research, and understanding the causes of chronic conditions.OBJECTIVE To determine and quantify regions of septal deformity that can be used to develop a comprehensive classification system. DESIGN, SETTING, AND PARTICIPANTSA retrospective case series study was conducted at an academic tertiary care hospital. Sixty-four participants were selected based on a convenience sample of computed tomography (CT) scans of the paranasal sinuses and midface available between June 29, 2011, and August 16, 2012. Exclusion criteria consisted of incomplete or inadequate CT series. The most recent CT scans were chosen for analyses regardless of the indication for imaging. Digital Imaging and Communications in Medicine format bitmap file-formatted data were obtained and analyzed using MATLAB and OsiriX. The line to curve ratio, deviation area, and root mean square (RMS) values of the septal contour vs the ideal straight septum fit were calculated. Analysis was performed to detect significant differences (P < .05) using the 3 measures. MAIN OUTCOMES AND MEASURESQuantitative analysis of nasal septal deviation. RESULTSThe population consisted of 50 male and 14 female patients aged 3 to 83 years (mean, 42 years). Mean line to curve ratios, areas, and RMS values were highest in contours that intersected the perpendicular plate-vomer junction, with a mean line to curve ratio of 1.04 and mean deviated area of 627.16 arbitrary units (P = .02). Maximal deviation areas were also seen midway from the perpendicular plate-vomer junction to the nasal spine with a mean area of 577.31 arbitrary units (P = .01). The RMS values were significantly elevated along the crista galli and perpendicular plate-vomer junction (P < .05). CONCLUSIONS AND RELEVANCEMaximum septal deviation is seen at the perpendicular plate-vomer junction and in the regions near the crista galli and anterior nasal spine. Deviation area and RMS values are important measures to characterize septal deviations. Understanding septal deviations can aid in developing a functional classification system of nasal septal deviations for clinical use and a means to better record and compare surgical outcomes.LEVEL OF EVIDENCE NA.

Brain AVMs treated with stereotactic radiosurgery typically demonstrate a minimum latency period of 1-3 years between treatment and nidus obliteration. Assessment of treatment response is usually limited to evaluation of AVM nidus structural changes using conventional MR imaging and MRA techniques. This report describes the use of 4D Flow MRI to also measure radiation-induced hemodynamic changes in a Spetzler-Martin grade III AVM, which were detectable as early as 6 months after treatment.