Clinical, Imaging, and Lab Correlates of Severe COVID-19 Leukoencephalopathy.

BACKGROUND AND PURPOSE: Patients infected with the Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) can develop a spectrum of neurological disorders, including a leukoencephalopathy of variable severity. Our aim was to characterize imaging, lab, and clinical correlates of severe coronavirus disease 2019 (COVID-19) leukoencephalopathy, which may provide insight into the SARS-CoV-2 pathophysiology. MATERIALS AND METHODS: Twenty-seven consecutive patients positive for SARS-CoV-2 who had brain MR imaging following intensive care unit admission were included. Seven (7/27, 26%) developed an unusual pattern of "leukoencephalopathy with reduced diffusivity" on diffusion-weighted MR imaging. The remaining patients did not exhibit this pattern. Clinical and laboratory indices, as well as neuroimaging findings, were compared between groups. RESULTS: The reduced-diffusivity group had a significantly higher body mass index (36 versus 28 kg/m2, P < .01). Patients with reduced diffusivity trended toward more frequent acute renal failure (7/7, 100% versus 9/20, 45%; P = .06) and lower estimated glomerular filtration rate values (49 versus 85 mL/min; P = .06) at the time of MRI. Patients with reduced diffusivity also showed lesser mean values of the lowest hemoglobin levels (8.1 versus 10.2 g/dL, P < .05) and higher serum sodium levels (147 versus 139 mmol/L, P = .04) within 24 hours before MR imaging. The reduced-diffusivity group showed a striking and highly reproducible distribution of confluent, predominantly symmetric, supratentorial, and middle cerebellar peduncular white matter lesions (P < .001). CONCLUSIONS: Our findings highlight notable correlations between severe COVID-19 leukoencephalopathy with reduced diffusivity and obesity, acute renal failure, mild hypernatremia, anemia, and an unusual brain MR imaging white matter lesion distribution pattern. Together, these observations may shed light on possible SARS-CoV-2 pathophysiologic mechanisms associated with leukoencephalopathy, including borderzone ischemic changes, electrolyte transport disturbances, and silent hypoxia in the setting of the known cytokine storm syndrome that accompanies severe COVID-19.

CT perfusion mean transit time maps optimally distinguish benign oligemia from true "at-risk" ischemic penumbra, but thresholds vary by postprocessing technique.

BACKGROUND AND PURPOSE: Various CTP parameters have been used to identify ischemic penumbra. The purpose of this study was to determine the optimal CTP parameter and threshold to distinguish true "at-risk" penumbra from benign oligemia in acute stroke patients without reperfusion. MATERIALS AND METHODS: Consecutive stroke patients were screened and 23 met the following criteria: 1) admission scanning within 9 hours of onset, 2) CTA confirmation of large vessel occlusion, 3) no late clinical or radiographic evidence of reperfusion, 4) no thrombolytic therapy, 5) DWI imaging within 3 hours of CTP, and 6) either CT or MR follow-up imaging. CTP was postprocessed with commercial software packages, using standard and delay-corrected deconvolution algorithms. Relative cerebral blood flow, volume, and mean transit time (rCBF, rCBV and rMTT) values were obtained by normalization to the uninvolved hemisphere. The admission DWI and final infarct were transposed onto the CTP maps and receiver operating characteristic curve analysis was performed to determine optimal thresholds for each perfusion parameter in defining penumbra destined to infarct. RESULTS: Relative and absolute MTT identified penumbra destined to infarct more accurately than CBF or CBV*CBF (P < .01). Absolute and relative MTT thresholds for defining penumbra were 12s and 249% for the standard and 13.5s and 150% for the delay-corrected algorithms, respectively. CONCLUSIONS: Appropriately thresholded absolute and relative MTT-CTP maps optimally distinguish "at-risk" penumbra from benign oligemia in acute stroke patients with large-vessel occlusion and no reperfusion. The precise threshold values may vary, however, depending on the postprocessing technique used for CTP map construction.

Cranial CT with adaptive statistical iterative reconstruction: improved image quality with concomitant radiation dose reduction.

BACKGROUND AND PURPOSE: To safeguard patient health, there is great interest in CT radiation-dose reduction. The purpose of this study was to evaluate the impact of an iterative-reconstruction algorithm, ASIR, on image-quality measures in reduced-dose head CT scans for adult patients. MATERIALS AND METHODS: Using a 64-section scanner, we analyzed 100 reduced-dose adult head CT scans at 6 predefined levels of ASIR blended with FBP reconstruction. These scans were compared with 50 CT scans previously obtained at a higher routine dose without ASIR reconstruction. SNR and CNR were computed from Hounsfield unit measurements of normal GM and WM of brain parenchyma. A blinded qualitative analysis was performed in 10 lower-dose CT datasets compared with higher-dose ones without ASIR. Phantom data analysis was also performed. RESULTS: Lower-dose scans without ASIR had significantly lower mean GM and WM SNR (P = .003) and similar GM-WM CNR values compared with higher routine-dose scans. However, at ASIR levels of 20%-40%, there was no statistically significant difference in SNR, and at ASIR levels of ≥60%, the SNR values of the reduced-dose scans were significantly higher (P < .01). CNR values were also significantly higher at ASIR levels of ≥40% (P < .01). Blinded qualitative review demonstrated significant improvements in perceived image noise, artifacts, and GM-WM differentiation at ASIR levels ≥60% (P < .01). CONCLUSIONS: These results demonstrate that the use of ASIR in adult head CT scans reduces image noise and increases low-contrast resolution, while allowing lower radiation doses without affecting spatial resolution.

Frequency of adequate contrast opacification of the major intracranial venous structures with CT angiography in the setting of intracerebral hemorrhage: comparison of 16- and 64-section CT angiography techniques.

BACKGROUND AND PURPOSE: DVST is an important cause of ICH because its treatment may require anticoagulation or mechanical thrombectomy. We aimed to determine the frequency of adequate contrast opacification of the major intracranial venous structures in CTAs performed for ICH evaluation, which is an essential factor in excluding DVST as the ICH etiology. MATERIALS AND METHODS: Two readers retrospectively reviewed CTAs performed in 170 consecutive patients with ICH who presented to our emergency department during a 1-year period to determine by consensus whether qualitatively, contrast opacification in each of the major intracranial venous structures was adequate to exclude DVST. "Adequate contrast opacification" was defined as homogeneous opacification of the venous structure examined. "Inadequate contrast opacification" was defined as either inhomogeneous opacification or nonopacification of the venous structure examined. Delayed scans, if obtained, were reviewed by the same readers blinded to the first-pass CTAs to determine the adequacy of contrast opacification in the venous structures according to the same criteria. In patients who did not have an arterial ICH etiology, the same readers determined if thrombosis of an inadequately opacified intracranial venous structure could have potentially explained the ICH by correlating the presumed venous drainage path of the ICH with the presence of inadequate contrast opacification within the venous structure draining the venous territory of the ICH. CTAs were performed in 16- or 64-section CT scanners with bolus-tracking, scanning from C1 to the vertex. Patients with a final diagnosis of DVST were excluded. We used the Pearson χ(2) test to determine the significance of the differences in the frequency of adequate contrast opacification within each of the major intracranial venous structures in scans obtained using either a 16- or 64-section MDCTA technique. RESULTS: Fifty-eight patients were evaluated with a 16-section MDCTA technique (34.1%) and 112 with a 64-section technique (65.9%). Adequate contrast opacification within all major noncavernous intracranial venous structures was significantly less frequent in first-pass CTAs performed with a 64-section technique (33%) than in those performed with a 16-section technique (60%, P value < .0001). Delayed scans were obtained in 50 patients, all of which demonstrated adequate contrast opacification in the major noncavernous intracranial venous structures. In 142 patients with supratentorial or cerebellar ICH without an underlying arterial etiology, we found that thrombosis of an inadequately opacified major intracranial venous structure could have potentially explained the ICH in 38 patients (26.8%), most examined with a 64-section technique (86.8%). CONCLUSIONS: Inadequate contrast opacification of the major intracranial venous structures is common in first-pass CTAs performed for ICH evaluation, particularly if performed with a 64-section technique. Acquiring delayed scans appears necessary to confidently exclude DVST when there is strong clinical or radiologic suspicion.

Functional contrast-enhanced CT for evaluation of acute ischemic stroke does not increase the risk of contrast-induced nephropathy.

BACKGROUND AND PURPOSE: Concerns have recently grown regarding the safety of iodinated contrast agents used for CTA and CTP imaging. We tested whether the incidence of AN, defined by a >or=25% increase in the post-contrast scan creatinine level, was higher among patients with ischemic stroke who underwent a functional contrast-enhanced CT protocol compared with those who had no iodinated contrast administration. MATERIALS AND METHODS: The contrast-exposed group consisted of 575 patients with acute ischemic stroke who underwent CTA (n = 313), CTA/CTP (n = 224), or CTA/CTP followed by conventional angiography (n = 38) within 24 hours of stroke onset and were consecutively enrolled in a prospective cohort study. The nonexposed group consisted of 343 patients with ischemic stroke, consecutively admitted to the same institution, who did not receive iodinated contrast material. Patients were stratified by baseline eGFR. In the primary analysis, the Fisher exact test was used to compare the incidence of AN between the contrast-exposed and the nonexposed patients at 24, 48, and 72 hours and on a cumulative basis. A secondary analysis compared the incidence of AN in patients who underwent conventional angiography following CTA/CTP versus patients who underwent CTA/CTP only. RESULTS: The incidence of AN was 5% in the exposed and 10% in the nonexposed group (P = .003). Patients who underwent conventional angiography after contrast CT were at no greater risk of AN than patients who underwent CTA/CTP alone (26 patients, 5%; and 2 patients, 5%, respectively; P = .7). CONCLUSIONS: Administration of a contrast-enhanced CT protocol involving CTA/CTP and conventional angiography in selected patients does not appear to increase the incidence of CIN.

Value of coronal reformations in the CT evaluation of acute head trauma.

BACKGROUND AND PURPOSE: Routine axial CT images may not be ideally suited for detecting ICH in transversely oriented locations such as the floor of the anterior and middle cranial fossas and vertex. This study was performed to evaluate whether coronal reformations improve detection of ICH in NCCT performed for head trauma. MATERIALS AND METHODS: All patients undergoing a first NCCT in the ED for evaluation of head trauma were included prospectively during a 6-month interval. NCCT images were reconstructed into standard 5-mm axial datasets and were also reformatted into coronal datasets of 5-mm sections and 2.5-mm intervals. Thirty-two of 213 (15%) scans were interpreted as showing traumatic ICH. These cases were interspersed with 30 studies without ICH. Cases were reviewed for the presence and location of ICH by 2 staff neuroradiologists. RESULTS: Of 213 patients, 32 NCCTs demonstrated ICH (a total of 104 foci). Fifteen of 104 (14%) ICHs (8 patients) were detected solely on coronal images. Locations included the floor of the anterior and middle cranial fossas, vertex, corpus callosum, falx, tentorium, and occipital convexity. Coronal reformations allowed exclusion of suspicious findings on axial images in 14 instances (7 patients). Coronal images aided interpretation in 29/104 (28%) findings. CONCLUSIONS: Coronal reformations improve the detection of ICH over axial images alone, especially for lesions that lie in the axial plane immediately adjacent to bony surfaces. The use of coronal reformations should be considered in the routine interpretation of head CT examinations performed for the evaluation of head trauma.

Privacy and patient-clergy access: perspectives of patients admitted to hospital.

BACKGROUND: For patients admitted to hospital both pastoral care and privacy or confidentiality are important. Rules related to each have come into conflict recently in the US. Federal laws and other rules protect confidentiality in ways that countermand hospitals' methods for facilitating access to pastoral care. This leads to conflicts and poses an unusual type of dilemma-one of conflicting values and rights. As interests are elements necessary for establishing rights, it is important to explore patients' interests in privacy compared with their desire for attention from a cleric. AIM: To assess the willingness of patients to have their names and rooms included on a list by religion, having that information given to clergy without their consent, their sense of privacy violation if that were done and their views about patients' privacy rights. METHODS AND PARTICIPANTS: 179 patients, aged 18-92 years, admitted to hospital in an acute care setting, were interviewed and asked about their preferences for confidentiality and pastoral support. RESULTS: Most (57%) patients did not want to be listed by religion; 58% did not think hospitals should give lists to clergy without their consent and 84% welcomed a visit by their own clergy even if triggered from a hospital list. CONCLUSIONS: Values related to confidentiality or privacy and pastoral care were found to be inconsistent and more complicated than expected. Balancing the right to privacy and the value of religious support continue to present a challenge for hospitals. Patients' preferences support the importance of providing balance in a way that protects rights while offering comprehensive services.

Resumption of oocyte meiosis in mammals: on models, meiosis activating sterols, steroids and EGF-like factors.

De novo synthesis of meiosis activating sterols (MAS) was stimulated by LH- and AY-9944 in rat cultured follicles and cumulus oocyte complexes (COCs), but could not be measured in denuded oocytes. Thus, MAS synthesized by the somatic compartment of the follicle could serve as a signal for the resumption of meiosis. Nevertheless, the delay in germinal vesicle breakdown (GVB) after MAS or AY-9944 stimulation as compared with gonadotropins, obtained by several groups, remains the strongest evidence against the suggested role of MAS as an essential mediator of LH in meiosis resumption. Recently several studies using mammalian COCs in culture have implied that steroids, like in fish and amphibians, serve as signals in mediating the LH/hCG stimulation of meiosis. However, in these studies there was no clear distinction between the requirement for steroids for the acquisition of meiotic competence, oocyte and follicle wellbeing or as a signal for meiotic resumption. Further, some of the authors overlooked earlier studies showing that blocking ovarian or follicular steroidogenesis does not affect GVB, the first step of meiosis resumption. Finally, in vivo and in vitro studies in the rat confirm and extend recent studies showing that locally produced and released EGF-like factors, such as epiregulin, seem to mediate at least part of the LH/hCG actions on oocyte maturation and release of ova at ovulation.

Radiologists' productivity in the interpretation of CT scans: a comparison of PACS with conventional film.

OBJECTIVE: We compared radiologists' times in the interpretation of CT using hardcopy films with the interpretation using a soft-copy picture archiving and communication system (PACS) computer workstation. MATERIALS AND METHODS: One hundred CT examinations were selected at random and reviewed by four board-certified radiologists experienced in soft-copy interpretation. We performed time-motion analysis to determine the total time required to display, interpret, and dictate the individual findings of CT using conventional hard-copy interpretation on a viewbox and soft-copy interpretation, using a four-monitor high-resolution (2048 x 1536 pixel) workstation. RESULTS: Time-motion analysis showed a reduction of 16.2% in the overall time required for soft-copy interpretation of CT compared with that of film. Time savings with soft-copy interpretation were observed for all four participating radiologists. The benefit of soft-copy interpretation was increased for examinations in which there were comparison studies. CONCLUSION: We found that soft-copy interpretation of CT using a PACS workstation requires less time than interpretation using conventional film hung on a viewbox. The transition to filmless imaging has the potential to improve radiologists' productivity and report-turnaround time.

Prevalence of cocaine use and its impact on asthma exacerbation in an urban population.

OBJECTIVES: To assess the prevalence of cocaine use, and its impact on severity of presentation, among adults presenting to the emergency department (ED) with asthma. A secondary aim was to assess the use of various asthma treatment modalities, with reference to the 1997 National Asthma Education and Prevention Program (NAEPP) guidelines. METHODS: All adults aged 18 to 55 years who presented to the ED of this institution with an asthma attack, were approached about participating in the study, which required giving informed consent, answering a facilitated questionnaire, and giving a urine sample for drug screening. RESULTS: Patients were enrolled during a 7-month period. A total of 163 patients were approached to enter the study; 116 patients consented to participate in the study, with 103 submitting complete urine samples. Thirty-seven patients refused to participate, and 10 were excluded. Sixty-eight percent of the patients were women, with a mean age of 33 years. African-Americans made up 89% of the total group. Thirty-five percent were cigarette smokers. Urine cocaine tests were positive in 13 of 103 (13%); 6 of 103 (5.8%) were positive for opiates. In the cocaine-positive group, 5 of 13 patients (38%) were admitted to the hospital, including two patients requiring intubation and mechanical ventilation. Of the total group, 23 of 103 patients (22%) were admitted, and 5 of those 23 admitted patients (22%) were cocaine-positive. Length of stay was significantly longer (5 vs 2.5 days, p < 0.05) in the cocaine-positive admitted patients. Forty-six percent of all patients reported using inhaled corticosteroids (ICS), with 39% of admitted patients using them. Thirty-two percent of all patients had obtained three or more refills of their beta(2)-agonist inhaler in the previous month. CONCLUSIONS: The prevalence of cocaine use may be much higher than the 13% shown in this study, because of patients' refusal to participate in the study. Second, the severity of exacerbation appears to be worse in the cocaine-positive group. Finally, the majority of patients presenting did not use ICS in accordance with the NAEPP guidelines.

Liver and bone window settings for soft-copy interpretation of chest and abdominal CT.

OBJECTIVE: We evaluated whether the use of multiple window and level settings on a soft-copy workstation improves diagnostic accuracy on chest and abdominal CT. We hypothesized that routinely using window and level settings during soft-copy interpretation would beneficially affect the final diagnosis without compromising efficiency. MATERIALS AND METHODS: Two hundred three randomly selected abdominal and chest CT scans were interpreted by three radiologists using a four-monitor soft-copy workstation (images per screen, nine; resolution, 2K). After the initial interpretations, all scans were reevaluated by the same radiologists using additional liver and bone window and level settings. Differences in conspicuity and characterization of abnormalities were graded on a three-point scale. RESULTS: Conspicuity and characterization of abnormalities were improved in 67% of abnormal findings (81/121; p = 0.01). Improvement (a finding that substantially affected the final diagnosis) was present in 18% of abnormal findings (22/121; p = 0.04). On average, the evaluation of images at multiple window and level settings required an additional 40 sec per case. CONCLUSION: The use of multiple window and level settings during soft-copy interpretation resulted in improved lesion detectability and characterization with greater diagnostic efficacy. Using soft-copy workstations, radiologists can evaluate images using multiple settings without compromising efficiency.

MammoWeb continuing medical education (CME): a web-based breast imaging CME program.

The ubiquity of the world-wide web allows unique educational opportunities for continuing medical education (CME). We have designed a comprehensive breast imaging CME curriculum to permit individual physicians in their homes or offices to use personal computers to ease the burden of this process. Category 1 CME credits can be earned off-hours without having the physician travel out of town. In addition, since the course is computer-based, the overall costs to the participant are substantially reduced. The program can be updated on an ongoing basis to include new technology or to provide additional information requested by the users.

Reduced misreading of asparagine codons by Escherichia coli tRNALys with hypomodified derivatives of 5-methylaminomethyl-2-thiouridine in the wobble position.

It has been suggested that modified nucleosides of the xm5(s2)U(m)34-type restrict the wobble capacity of the base, and that their function is to prevent misreading in the third position of the codon in mixed codon family boxes that encode two different amino acids. In this study in Escherichia coli, the misreading in vivo of asparagine codons in bacteriophage MS2 mRNA by different hypomodified derivatives of tRNALys, normally containing 5-methylaminomethyl-2-thiouridine (mnm5s2U34) in the wobble position, has been analysed. Contrary to what would be predicted from the general hypothesis for the function of mnm5s2U, it was found that the misreading of asparagine codons by tRNALys was greatly reduced in the mnmA (formerly asuE or trmU) and mnmE (formerly trmE) mutants which contain the hypomodified mnm5U34 and s2U34, respectively, instead of the fully modified mnm5s2U34. In addition, it was found that these hypomodified tRNAs were efficiently charged with lysine in vivo, under the growth conditions employed. The latter result is at variance with results obtained in vitro. The results are discussed in relation to the postulated function for modified nucleosides of the xm5s2U type.

Substance use during sex and unsafe sexual behaviors among acute psychiatric inpatients.

A total of 239 acute psychiatric inpatients were interviewed about whether they used substances just before or during sex and whether they engaged in unsafe sexual behaviors while using substances. Nearly 40 percent of male patients and 36 percent of female patients reported using alcohol at least once during sex in the previous six months. Among male patients a statistically significant association was observed between using crack during sex and two high-risk behaviors--inconsistent condom use and sex with a high-risk partner. Among female patients the use of alcohol before or during sex was significantly associated with the practice of receptive anal sex.