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Enlarged perivascular spaces (EPVS), specifically in stroke patients, has been shown to strongly correlate with other measures of small vessel disease and cognitive impairment at 1 year follow-up. Typical grading of EPVS is often challenging and time consuming and is usually based on a subjective visual rating scale. The purpose of the current study was to develop an interpretable, 3D neural network for grading enlarged perivascular spaces (EPVS) severity at the level of the basal ganglia using clinical-grade imaging in a heterogenous acute stroke cohort, in the context of total cerebral small vessel disease (CSVD) burden. T2-weighted images from a retrospective cohort of 262 acute stroke patients, collected in 2015 from 5 regional medical centers, were used for analyses. Patients were given a label of 0 for none-to-mild EPVS (< 10) and 1 for moderate-to-severe EPVS (≥ 10). A three-dimensional residual network of 152 layers (3D-ResNet-152) was created to predict EPVS severity and 3D gradient class activation mapping (3DGradCAM) was used for visual interpretation of results. Our model achieved an accuracy 0.897 and area-under-the-curve of 0.879 on a hold-out test set of 15% of the total cohort (n = 39). 3DGradCAM showed areas of focus that were in physiologically valid locations, including other prevalent areas for EPVS. These maps also suggested that distribution of class activation values is indicative of the confidence in the model's decision. Potential clinical implications of our results include: (1) support for feasibility of automated of EPVS scoring using clinical-grade neuroimaging data, potentially alleviating rater subjectivity and improving confidence of visual rating scales, and (2) demonstration that explainable models are critical for clinical translation., (© 2022. The Author(s).)

Rationale and Objectives: Following state and institutional guidelines, our Radiology department launched the "Recover Wisely" for all nonurgent radiology care on May 4, 2020. Our objective is to report our practice implementation and experience of COVID-19 recovery during the resumption of routine imaging at a tertiary academic medical center., Materials and Methods: We used the SQUIRE 2.0 guidelines for this practice implementation. Recover Wisely focused on a data driven, strategic rescheduling and redesigning patient flow process. We used scheduling simulations and meticulous monitoring and control of outpatient medical imaging volumes to achieve a linear restoration to our pre-COVID imaging studies. We had a tiered plan to address the backlog of rescheduled patients with gradual opening of our imaging facilities, while maintaining broad communication with our patients and referring clinicians., Results: Recover Wisely followed our anticipated linear modeling. Considering the last 10 weeks in the recovery, outpatient growth was linear with an increase of approximately 172 cases per week, (R 2 =0.97). We achieved an overall recovery of 102% in week 10, as compared to average weekly pre-COVID outpatient volumes. The modalities recovered as follows in outpatient volumes: CT (113%), MRI (101%), nuclear medicine including PET (138%), mammograms (97%), ultrasound (99%) and interventional radiology (106%). When compared to identical 2019 calendar weeks (May 4, 2020-July 10, 2020), the total 2020 radiology volume was 11% reduced from the 2019 volume. The reduction in total weighted relative value units was 8% in this time period, as compared to 2019., Conclusion: Our department utilized a data-driven, team approach based on our guiding principles to "Recover Wisely." We created and implemented a methodology that achieved a linear increase in outpatient studies over a 10-week recovery period., Competing Interests: Conflicts of Interests AV: R01 NIH/NINDS NS103824-01; R01 NIH/NINDS NS100417; NIH/NINDS 1U01NS100699; NIH/NINDS U01NS110772; Imaging Core Lab, ENDOLOW Trial, Cerenovus, Johnson & Johnson; Human centered design grant, ACR Innovation Fund. FR: Director of Medical Affairs at Imagia. MM: RSNA BOD, ACR BOC, Nonfinancial support from GE research agreement, Personal fees from Elsevier. JA, BA, JH, SC, KC, SK, MG, AM, AB, SB, EE, JS, GU: No conflicts to disclose, (Copyright © 2020 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

OBJECTIVE. This article provides comments from a small group of highly qualified reviewers of the American Journal of Roentgenology ( AJR ) regarding their approach to assessing manuscripts. The objective is to educate authors about the issues to which reviewers particularly attend and about errors that will decrease the likelihood of publication. CONCLUSION. By following the advice provided in this article, authors should be able to compose better manuscripts and reviewers should be able to generate better reviews.

Purpose: Texture analysis (TA) can quantify variations in surface intensity or patterns, including some that are imperceptible to the human visual system. The purpose of this study was to determine the diagnostic accuracy of radiomic based filtration-histogram TA to differentiate high-grade from low-grade gliomas by assessing tumor heterogeneity., Methods: Patients with a histopathological diagnosis of glioma and preoperative 3T MRI imaging were included in this retrospective study. A region of interest was manually delineated on post-contrast T1 images. TA was performed using commercially available research software. The histogram parameters including mean, standard deviation, entropy, mean of the positive pixels, skewness, and kurtosis were analyzed at spatial scaling factors ranging from 0 to 6 mm. The parameters were correlated with WHO glioma grade using Spearman correlation. Areas under the curve (AUC) were calculated using ROC curve analysis to distinguish tumor grades., Results: Of a total of 94 patients, 14 had low-grade gliomas and 80 had high-grade gliomas. Mean, SD, MPP, entropy and kurtosis each showed significant differences between glioma grades for different spatial scaling filters. Low and high-grade gliomas were best-discriminated using mean of 2 mm fine texture scale, with a sensitivity and specificity of 93% and 86% (AUC of 0.90)., Conclusions: Quantitative measurement of heterogeneity using TA can discriminate high versus low-grade gliomas. Radiomic data of texture features can provide complementary diagnostic information for gliomas.

Purpose: The diagnosis of intracranial tuberculomas is often challenging. Our purpose is to describe the most common metabolic patterns of tuberculomas by MR spectroscopy (MRS) with emphasis on potential specific markers., Methods: Single-voxel MRS short echo time was performed in 13 cases of tuberculomas proven by histology and/or response to anti-mycobacterial therapy. For comparison MRS was also performed in 19 biopsy-proven malignant tumors (13 high-grade gliomas and six metastasis). Presence of metabolic peaks was assessed visually and categorical variables between groups were compared using chi-square. Metabolite ratios were compared using Mann-Whitney test and diagnostic accuracy of the metabolite ratios was compared using receiver-operating characteristic (ROC) curves analysis., Results: Spectroscopic peaks representing lipids and glutamate/glutamine (Glx) as well as a peak at ∼3.8 ppm were well defined in 77% (10/13), 77% (10/13) and 69% (nine of 13) of tuberculomas, respectively. Lipid and Glx peaks were also present in most of the malignant lesions, 79% (15/19) and 74% (14/19) respectively. However, a peak at ∼3.8 ppm was present in only 10% (two of 19) of the tumor cases (p < 0.001). Higher Cho/Cr and mI/Cr ratios helped discriminate malignant lesions with an area under the ROC curve of 0.86 (SE: 0.078, p < 0.002, CI: 0.7-1) and 0.8 (SE: 0.1, p < 0.009, CI: 0.6-1), respectively. Threshold values between 1.7-1.9 for Cho/Cr and 0.8-0.9 for mI/Cr provided high specificity (91% for both metabolites) and adequate sensitivity (75% and 80%, respectively) for discrimination of malignant lesions., Conclusion: A singlet peak at ∼3.8 ppm is present in the majority of tuberculomas and absent in most malignant tumors, potentially a marker to differentiate these lesions. The assignment of the peak is difficult from our analysis; however, guanidinoacetate (Gua) is a possibility. Higher Cho/Cr and mI/Cr ratios should favor malignant lesions over tuberculomas. The presence of lipids and Glx is non-specific., (© The Author(s) 2015.)

Background: Uncertainty exists about a safe dose limit to minimize radiation-induced cancer. Maximum occupational exposure is 20 mSv/y averaged over 5 years with no more than 50 mSv in any single year. Radiation exposure to the general population is less, but the average dose in the United States has doubled in the past 30 years, largely from medical radiation exposure. We hypothesized that patients in a mixed-use surgical ICU (SICU) approach or exceed this limit and that trauma patients were more likely to exceed 50 mSv because of frequent diagnostic imaging., Methods: Patients admitted into 15 predesignated SICU beds in a level I trauma center during a 30-day consecutive period were prospectively observed. Effective dose was determined using Huda's method for all radiography, CT imaging, and fluoroscopic examinations. Univariate and multivariable linear regressions were used to analyze the relationships between observed values and outcomes., Results: Five of 74 patients (6.8%) exceeded exposures of 50 mSv. Univariate analysis showed trauma designation, length of stay, number of CT scans, fluoroscopy minutes, and number of general radiographs were all associated with increased doses, leading to exceeding occupational exposure limits. In a multivariable analysis, only the number of CT scans and fluoroscopy minutes remained significantly associated with increased whole-body radiation dose., Conclusions: Radiation levels frequently exceeded occupational exposure standards. CT imaging contributed the most exposure. Health-care providers must practice efficient stewardship of radiologic imaging in all critically ill and injured patients. Diagnostic benefit must always be weighed against the risk of cumulative radiation dose.

Background and Purpose: Cerebral venous thrombus (CVT) signal intensity is variable on MR imaging, and the appearance of CVT on gradient recalled-echo (GRE) sequences has been incompletely assessed. This study was performed to evaluate the GRE imaging appearance of CVT in different stages of thrombus evolution and its relationship to signal intensity on other MR pulse sequences., Materials and Methods: The clinical and MR imaging findings in 18 patients with CVT and GRE imaging were reviewed. Sixty-nine thrombosed venous segments were evaluated, and the signal intensity of thrombus relative to gray matter was determined. The degree of thrombus susceptibility effect (SE) was assessed and related to time of imaging after onset of symptoms (clinical thrombus age) and appearance on other pulse sequences. Segments were classified as SE+ (demonstrating susceptibility effect) or SE- (no susceptibility effect)., Results: Thirty-six venous segments exhibited visible SE. SE+ segments had a clinical thrombus age that was less than that in SE- segments (8.1 versus 24.6 days, P=.003). Sixty-three percent (23/36) of SE+ segments exhibited hypointensity on T2-weighted images (T2WI) versus 12% (4/33) of SE- segments (P<.001). Twenty-nine of 32 (90.6%) segments with clinical thrombus age of 0-7 days were SE+, versus 7 of 30 (23.3%) segments with a thrombus age of 8 days or greater., Conclusion: SEs from CVT can be detected with GRE imaging and are most prevalent in patients with hypointense thrombus on T2WI within 7 days after the symptom onset. This correlates with the paramagnetic effects of deoxyhemoglobin in acute stage thrombus. GRE imaging may be useful in detecting thrombus in this stage when difficult to detect on other pulse sequences.

Objective: Well-established surgical goals for pituitary macroadenomas include gross total resection for noninvasive tumors and debulking with optic chiasm decompression for invasive tumors. In this report, we examine the safety, reliability, and outcome of intraoperative magnetic resonance imaging (iMRI) used to assess the extent of resection, and thus the achievement of preoperative surgical goals, during transsphenoidal microneurosurgery., Methods: Our magnetic resonance operating room contains a Hitachi AIRIS II 0.3-T, vertical-field open magnet (Hitachi Medical Systems America, Inc., Twinsburg, OH). A motorized scanner tabletop moves the patient between the imaging and operative positions. For transsphenoidal surgery, the patient is positioned directly on the scanner tabletop so that the surgical field is located between 1.2 and 1.6 m from the magnet isocenter. At this location, the magnetic field strength is low (<20 G), thus permitting the use of many conventional surgical instruments. Thirty consecutive patients with pituitary macroadenomas underwent tumor resection in our magnetic resonance operating room by use of a standard transsphenoidal approach. After initial resection, the patient was advanced into the scanner for imaging. If residual tumor was demonstrated and deemed surgically accessible, the patient underwent immediate re-exploration., Results: iMRI was performed successfully in all 30 patients. In one patient, iMRI was used to clarify the significance of hemorrhage from the sellar region and resulted in immediate conversion of the procedure to a craniotomy. In the remaining 29 patients, initial iMRI demonstrated that the endpoint for extent of resection had been achieved in only 10 patients (34%) after an initial resection attempt, whereas 19 patients (66%) still had unacceptable residual tumor. All 19 of these latter patients underwent re-exploration. Ultimately, re-exploration resulted in the achievement of the planned endpoint for extent of resection in all of the 29 completed transsphenoidal explorations. Operative time was extended in all cases by at least 20 minutes., Conclusion: iMRI can be used to safely, reliably, and objectively assess the extent of resection of pituitary macroadenomas during the transsphenoidal approach. The surgeon is frequently surprised by the extent of residual tumor after an initial resection attempt and finds the intraoperative images useful for guiding further resection.

Objective: We describe a shared-resource intraoperative magnetic resonance imaging (MRI) design that allocates time for both surgical procedures and routine diagnostic imaging. We investigated the safety and efficacy of this design as applied to the detection of residual glioma immediately after an optimal image-guided frameless stereotactic resection (IGFSR)., Methods: Based on the twin operating rooms (ORs) concept, we installed a commercially available Hitachi AIRIS II, 0.3-tesla, vertical field, open MRI unit in its own specially designed OR (designated the magnetic resonance OR) immediately adjacent to a conventional neurosurgical OR. Between May 1998 and October 1999, this facility was used for both routine diagnostic imaging (969 diagnostic scans) and surgical procedures (50 craniotomies for tumor resection, 27 transsphenoidal explorations, and 5 biopsies). Our study group, from which prospective data were collected, consisted of 40 of these patients who had glioma (World Health Organization Grades II-IV). These 40 patients first underwent optimal IGFSRs in the adjacent conventional OR, where resection continued until the surgeon believed that all of the accessible tumor had been removed. Patients were then transferred to the magnetic resonance OR to check the completeness of the resection. If accessible residual tumor was observed, then a biopsy and an additional resection were performed. To validate intraoperative MRI findings, early postoperative MRI using a 1.5-tesla magnet was performed., Results: Intraoperative images that were suitable for interpretation were obtained for all 40 patients after optimal IGFSRs. In 19 patients (47%), intraoperative MRI studies confirmed that adequate resection had been achieved after IGFSR alone. Intraoperative MRI studies showed accessible residual tumors in the remaining 21 patients (53%), all of whom underwent additional resections. Early postoperative MRI studies were obtained in 39 patients, confirming that the desired final extent of resection had been achieved in all of these patients. One patient developed a superficial wound infection, and no hazardous equipment or instrumentation problems occurred., Conclusion: Use of an intraoperative MRI facility that permits both diagnostic imaging and surgical procedures is safe and may represent a more cost-effective approach than dedicated intraoperative units for some hospital centers. Although we clearly demonstrate an improvement in volumetric glioma resection as compared with IGFSR alone, further study is required to determine the impact of this approach on patient survival.

Cerebrovascular trauma includes a wide variety of injuries, including dissections, traumatic aneurysms, arteriovenous fistulas, and vascular occlusions. These entities, which are often underdiagnosed, can produce devastating neurologic complications. This article reviews the clinical and radiographic presentations of vascular trauma to increase awareness of these injuries and improve our ability to detect and treat them.

Background and Purpose: The role of intraoperative angiography in the treatment of neurovascular lesions has remained extremely controversial. We retrospectively reviewed the utility, safety, and accuracy of intraoperative angiography to ascertain its effect on the treatment of patients with neurovascular lesions., Methods: We reviewed the results of intraoperative angiography in 91 patients treated surgically for intracranial aneurysms and in 98 patients treated surgically for arteriovenous malformations (AVMs). All treatments were completed at two major teaching hospitals between October 1987 and March 1995., Results: The initial angiographic findings caused the surgical procedure to be modified in 24 (26%) of the patients with aneurysms and in 28 (29%) of the patients with AVMs. Analysis of the final angiographic sequence showed residual lesions in nine (10%) of the aneurysm cases and in eight (8%) of the AVM cases. The imperfect angiographic results were deemed acceptable because there was either evidence of collateral flow when the parent vessel was occluded or the risk of further surgical modification was considered more dangerous than the abnormality itself. Seven patients suffered complications, of which only one had permanent neurologic sequelae: a CNS complication rate of 0.5%. Comparison of the intraoperative angiographic findings with those of postoperative studies revealed four false-negative results (5.2%)., Conclusion: Intraoperative angiography is an important component in the treatment of patients with intracranial vascular lesions. It is effective and can be carried out with low risk in this patient population.

Although new imaging techniques such as MR perfusion/diffusion and xenon CT have shown considerable promise in the detection of early brain ischemia, noncontrast CT remains the primary imaging test for the evaluation of acute stroke. It is fast, reliable, readily available, and continues to be used for all major stroke therapy trials. Despite its limitations, CT is an accurate method of screening patients prior to thrombolytic therapy.

The MR findings in three patients with intracranial dural arteriovenous fistula associated with cervical myelopathy are described. The MR appearance of an enlarged cord with associated abnormal signal and enhancement is nonspecific and can simulate tumor, demyelination, and inflammation. Enlarged perimedullary vessels may not always be identifiable, but if present, should suggest the presence of an arteriovenous fistula.

Objective and Importance: Focal or diffuse corpus callosal changes can occur in patients with active hydrocephalus who undergo shunting procedures. The neural compression caused by active hydrocephalus and the conditions that follow ventricular shunting may contribute to the development of these changes., Clinical Presentation: Two patients who underwent successful shunting for hydrocephalus subsequently developed thickening and diffuse signal changes in the corpus callosum, which were revealed by magnetic resonance imaging. The abnormal signal intensity extended laterally and linearly along the callosal fiber tracts and was not associated with mass effect. These changes persisted despite clinical improvement after the shunts were implanted., Intervention: Detailed neuropsychological testing showed no evidence of residual cognitive impairment or any interruption of the interhemispheric transfer of information. It has been proposed that the impingement of the corpus callosum by the rigid falx may contribute to symptomatic hydrocephalus. Impingement may cause partial hemispheric disconnection, resulting from callosal axonal dysfunction. Our patients showed radiographic evidence of dramatic changes within the corpus callosum after ventricular shunting, consistent with a transcallosal demyelinating process. Patients demonstrated neither clinical nor neuropsychological evidence of callosal disconnection, even though the callosal changes persisted. In these two patients, it is reasonable to assume that the relative sparing of the splenium accounts for the lack of neuropsychological deficits., Conclusion: Based on our findings, conservative management, rather than a stereotactic biopsy or other forms of intervention, seems reasonable when these characteristic changes of the callosum are noted by magnetic resonance imaging after a shunt for hydrocephalus has been implanted in the patient.

Cerebrovascular trauma is a heterogeneous group of injuries including arterial dissections, traumatic aneurysms, arteriovenous fistulas, and venous occlusions. Detection of vascular trauma may be difficult because of variations in clinical presentation; however, in recent years, increased awareness and understanding of these injuries has improved the ability to detect and subsequently treat many lesions. Despite advances in other imaging modalities, angiography remains the primary radiographic tool used in the evaluation of traumatic vascular lesions.

Objective: To compare computed tomography (CT) with open neck exploration in determining prevertebral invasion by squamous cell carcinoma of the oropharynx or hypopharynx., Design: Retrospective analysis using the findings at open neck exploration and results of histopathologic studies as the criterion standards., Setting: Tertiary care referral center., Patients: Twenty-nine of 40 patients with advanced squamous cell carcinoma of the oropharynx or hypopharynx treated between January 1, 1986, and December 31, 1994, were selected for analysis based on CT findings of posterolateral extension of the primary tumor placing the prevertebral muscle (PVM) at risk. All study patients had no previous therapy and underwent neck exploration to determine resectability., Results: Overall accuracy of CT in predicting PVM status was 55.2%. The sensitivity of preoperative CT for PVM invasion was 50%; the specificity was 61%. Using an estimate of 21% for the prevalence of PVM invasion, the predictive value of a positive CT scan was 0.254 and the predictive value of a negative CT scan was 0.821. Open neck exploration correctly predicted PVM status in all cases., Conclusions: Open neck exploration is superior to CT to evaluate possible PVM invasion by squamous cell carcinoma of the oropharynx or hypopharynx. The predictive value of a negative CT scan for PVM invasion is high, so it may be useful in treatment planning. Patients with advanced squamous cell carcinoma of the oropharynx or hypopharynx at risk for PVM invasion who are otherwise surgical candidates should be considered for open neck exploration to determine resectability most accurately.

Three cases of intractable spontaneous posterior epistaxis refractory to nasal packing and complicated by ipsilateral carotid artery occlusive disease were successfully treated with internal maxillary artery occlusion with microcoils. There were no complications and no recurrent episodes of epistaxis at a mean follow-up of 12 months. The presence of ipsilateral carotid artery disease requires modification of standard distal internal maxillary artery embolization because of the recruitment of external carotid to internal carotid and external carotid to ophthalmic artery collateral pathways, with subsequent risk of particle embolization of these arterial distributions. Proximal internal maxillary artery microcoil embolization eliminates this risk and is equivalent to surgical internal maxillary artery ligation. This procedure also provides additional information about the internal carotid artery collateral circulation.