Metabolic characterization of AIDS dementia complex by spectroscopic imaging

Prospective proton chemical shift imaging (CSI) of the brain was performed in 30 HIV- 1-seropositive patients and 11 healthy controls. Significant (P < 0.05) reductions in the N-acetyl-L-aspartate (NAA)/total creatine (Cr), and NAA/total choline (Cho) ratios and significant increases in Cho/Cr occurred in patients with 1) AIDS-defining diagnoses; 2) <200 CD4 lymphocyte counts/microl; 3) neurological evidence for an AIDS dementia complex (ADC); 4) magnetic resonance imaging (MRI) signs of cerebral atrophy. The basal ganglia and the insula were affected to approximately the same extent and without indications of spatial variations within these areas. Reduced NAA seems to indicate progressive neuronal injury or loss due to productive HIV infection in the brain and its clinical picture ADC. Spectroscopic abnormalities were, however, also observed in neurologically normal HIV patients or those with normal MRI results. Proton CSI may therefore serve as an early quantitative marker of central nervous system involvement in AIDS.     

Whole brain imaging of HIV-infected patients: quantitative analysis of magnetization transfer ratio histogram and fractional brain volume

BACKGROUND AND PURPOSE: Magnetization transfer ratio (MTR) histogram analysis and volumetric MR imaging are sensitive tools with which to quantify the tissue destructive effects in patients with white matter or neurodegenerative disease. Our purpose was to determine whether whole brain MTR and fractional brain parenchyma volume measurements are altered in HIV-1-infected patients who are neurologically symptomatic and in those who are asymptomatic. METHODS: We performed MR imaging and MTR studies of 15 neurologically symptomatic (seven patients) and asymptomatic (eight patients) HIV-1-seropositive patients and compared their findings with those of 10 seronegative normal control participants. MTR was computed on the basis of whole brain parenchyma segmented by using thin section dual echo MR images. RESULTS: The loss of brain tissue, indicated by fractional brain parenchyma volume, was more pronounced in neurologically symptomatic patients (P =.003) but not in asymptomatic patients (P =.23) when compared with control participants. As for whole brain MTR histogram analysis, both patient groups showed significant decrease in mean (P =.02) and median (P < or =.009) values, compared with normal control participants. There was a trend toward positive correlation (r > or = 0.56) between MTR histogram statistics and fractional brain parenchyma volume. CONCLUSION: Our results suggest that MTR histogram analysis is sensitive in detecting early involvement in neurologically asymptomatic patients with HIV and may, therefore, be used as a combined tool with volumetric measurement, which showed significant tissue loss only in symptomatic patients, to assess various stages of brain damage induced by HIV.     

Evaluation of metabolic changes within the normal appearing gray and white matters in neurologically asymptomatic HIV-1-positive and HCV-positive patients: Magnetic resonance spectroscopy and immunologic correlation

Objective

The aim of the study was to evaluate early metabolic changes using proton MR spectroscopy (MRS) in asymptomatic HIV-1-positive and HCV-positive patients without abnormalities in the structural MR examination.

Methods

Sixty-five asymptomatic patients: 21 HIV-1-positive naive, 20 HIV-1-positive with combination antiretroviral therapy (cART), 9 HIV-1/HCV-positive naive, 15 HCV-positive naive and 18 normal subjects were enrolled in the study. The MRS examinations were performed with a 1.5 T MR scanner. Voxels were located in the following regions: posterior cingulate gyrus (PCG), anterior cingulate gyrus (ACG), parietal white matter (PWM), left basal ganglia (BG) and frontal white matter (FWM). The NAA/Cr, Cho/Cr, mI/Cr ratios and correlations of MRS measurements with the immunologic data were analyzed.

Results

There was a significant decrease (p < 0.05) of the NAA/Cr ratios in PCG, ACG and PWM regions in HIV-1-positive cART treated patients compared to the normal subjects. The significantly decreased NAA/Cr ratios in PWM and FWM were observed in HCV infected patients. The subjects with HIV-1/HCV co-infection revealed significantly lower NAA/Cr ratios in the ACG area. Other metabolite ratios in all analyzed regions, as well as the NAA/Cr ratios in BG showed no significant differences. The decrease of CD4n T cell count was associated with the decease of the NAA/Cr ratio in the PCG area and the increase of Cho/Cr ratio in the FWM region.

Conclusions

The metabolic changes – reduction of NAA/Cr ratios are most pronounced in HIV-1-positive patients using cART. The low CD4n T cell count is a risk factor for neurocognitive impairment in HIV-1-positive patients.     

Comparison of Clinical and Radiologic Findings Between Perforated and Non-Perforated Choledochal Cysts in Children

ObjectiveTo compare the clinical and radiologic findings between perforated and non-perforated choledochal cysts in children.Materials and MethodsFourteen patients (mean age ± standard deviation, 1.7 ± 1.2 years) with perforated choledochal cysts (perforated group) and 204 patients (3.6 ± 3.8 years) with non-perforated choledochal cysts (non-perforated group) were included between 2000 and 2019. All patients underwent choledochal cyst excision after ultrasound, CT, or MR cholangiopancreatography. Relevant data including demographics, clinical symptoms, laboratory findings, imaging findings, and outcomes were analyzed. Statistical differences were compared using the Mann-Whitney U test and Fisher’s exact test.ResultsCholedochal cyst perforation occurred only in children under the age of 4 years. Acute symptoms, including fever (p < 0.001), were more common in the perforated group than in the non-perforated group. High levels of white blood cells (p = 0.004), C-reactive protein (p < 0.001), and serum amylase (p = 0.002), and low levels of albumin (p < 0.001) were significantly associated with the perforated group. All 14 patients with perforated choledochal cysts had ascites, whereas only 16% (33/204) of patients in the non-perforated group had ascites (p < 0.001). In the subgroup of patients who had ascites, a large amount of ascites (p = 0.001), increase in the amount of ascites in a short time (p < 0.001), complex ascites (p < 0.001), and perihepatic pseudocysts (p < 0.001) were more common in the perforated group than in the non-perforated group.ConclusionChildren with perforated choledochal cysts have characteristic clinical and radiologic findings compared to those with non-perforated choledochal cysts. In young children with choledochal cysts, perforation should be differentiated in cases with acute symptoms, laboratory abnormalities, and characteristic ascites findings.     

Atypical Imaging Features of Epstein-Barr Virus–Positive Primary Central Nervous System Lymphomas in Patients without AIDS

BACKGROUND AND PURPOSE:Recent clinical experience with EBV-positive PCNSL in patients without acquired immune deficiency syndrome showed that they tended to have atypical features seen on conventional MR imaging. The purpose of our study was to evaluate the MR imaging features of EBV-positive PCNSL in patients without AIDS and to compare these imaging findings with those of EBV-negative PCNSL.MATERIALS AND METHODS:MR images were obtained in 55 consecutive patients with pathologically proved EBV-positive (n = 10) or EBV-negative (n = 45) PCNSL. We statistically analyzed the differences between the patient groups regarding the occurrence of tumor necrosis or hemorrhage and ADC, rCBV_max, rCBV_r, and the Cho/NAA ratio in the tumor area.RESULTS:Tumor necrosis and hemorrhage were observed in 9 (90%) and 7 (70%), respectively, of the patients with EBV-positive PCNSL; necrosis was observed in 8 (18%), and hemorrhage, in 3 (7%) patients with EBV-negative PCNSL (P < .0001 each). The necrotic core was hyperintense relative to contralateral white matter, as seen on DWI in 4 patients with EBV-positive PCNSL, though the ADC between the 2 patient groups did not differ significantly. rCBV_max, rCBV_r, and the Cho/NAA ratios did not differ significantly between the 2 groups. The sensitivity and specificity of necrosis and hemorrhage for differentiating the 2 groups were 89.2% and 81.7% and 78.5% and 94.1%, respectively.CONCLUSIONS:Our initial clinical experience with a small number of patients suggests that EBV-positive PCNSL in patients without AIDS tends to present with atypical MR imaging features.

EBV has been implicated in the pathogenesis of PCNSL in patients with congenital and acquired immunodeficiency,^1,2 though not in immunocompetent patients. Nevertheless, EBV has been observed in PCNSL in immunocompetent hosts, thus suggesting its role in PCNSL tumorigenesis in these individuals.^1–3Age-related, EBV-positive, diffuse, large B-cell lymphoma is a new disease entity in the 2008 World Health Organization classification occurring in the elderly^4,5 and mostly without any known immunodeficiency or prior lymphoma. This new disease entity has been characterized as having a propensity to involve extranodal sites and to be associated with a broad morphologic spectrum ranging from the precursor-reactive proliferation of lymphoid cells to overt lymphoma.^6–9To our knowledge, there have been no radiologic reports of CNS involvement of EBV-associated diffuse large-B-cell lymphoma in patients without acquired immune deficiency syndrome. We have encountered 10 consecutive patients without AIDS with EBV-positive PCNSL since June 2008. We hypothesized that EBV-positive PCNSL may show imaging features that differ from those of EBV-negative PCNSL but may have imaging features similar to those of PCNSL in patients with AIDS. We, therefore, assessed 10 consecutive patients without AIDS with EBV-positive PCNSL by using both conventional and advanced MR imaging and compared these imaging findings with those of patients without AIDS with EBV-negative PCNSL.     

Small rosarylike infarctions in the centrum ovale suggest hemodynamic failure.

BACKGROUND AND PURPOSELesions in the centrum ovale may be classified as microangiopathic (lacunar) lesions and hemodynamic infarctions. To distinguish between them, a size of more than 2 cm has been postulated for hemodynamic infarctions. The reliability of this criterion was assessed with MR imaging.METHODSIn 16 patients with unilateral or bilateral occlusion or high-grade stenosis of the internal carotid artery (ICA), CO2 testing revealed an ipsilateral hemodynamic failure. Each hemisphere in these patients was assessed separately for the presence and size of centrum ovale lesions.RESULTSFive of the 16 patients suffered from large cortical infarctions with a probable embolic pathogenesis. In the remaining 11 patients (22 hemispheres), a hemodynamic failure was found in 15 hemispheres, due to occlusion (13 hemispheres) or high-grade ICA stenosis (two hemispheres). MR imaging revealed centrum ovale infarctions with a size of more than 2 cm in three of the 15 hemispheres. In eight hemispheres, multiple small lesions (< 1.5 cm; three to 30 per hemisphere) could be found with a rosarylike or sickle-shaped distribution. In none of these eight cases did MR images show lacunar infarctions in the typical regions of the brain.CONCLUSIONOur results favor the assumption that the MR finding of multiple small (< 1.5 cm) rosarylike lesions in the centrum ovale seems to be typical in patients with hemodynamic failure due to severe ICA disease.     

Pretreatment Diagnosis of Suprasellar Papillary Craniopharyngioma and Germ Cell Tumors of Adult Patients

BACKGROUND AND PURPOSE:Suprasellar papillary craniopharyngiomas and germ cell tumors in adults share some clinical and imaging similarities but have different therapeutic strategies and outcomes. This study aimed to evaluate the pretreatment diagnosis of these 2 tumors to improve the therapeutic outcome.MATERIALS AND METHODS:We retrospectively enrolled 18 adults with papillary craniopharyngiomas and 17 with germ cell tumors. The MR imaging findings were evaluated, including signal change and anatomic extension. The medical records were reviewed to collect clinical findings, management, and outcomes.RESULTS:The clinical findings of papillary craniopharyngiomas versus germ cell tumors were as follows: age: 46 ± 13.9 years versus 23 ± 7.1 years (P < .0001); diabetes insipidus: 2/18 (11%) versus 11/17 (65%) (P = .001); recurrence 13/16 (81%) versus 4/17 (24%) (P = .0031). The MR imaging findings of papillary craniopharyngiomas versus germ cell tumors were as follows—pituitary stalk thickening: 1.6 ± 0.4 mm versus 5.4 ± 4.2 mm (P < .0001); vertical infundibular extension: 1/18 (6%) versus 16/17 (94%) (P < .0001); sagittal spheric shape: 17/18 (94%) versus 1/17 (6%) (P < .0001); diffusion restriction: 1/17 (6%) versus 8/12 (67%) (P = .0009).CONCLUSIONS:Younger age, diabetes insipidus, MR imaging characteristics of restricted diffusion, and vertical infundibular extension favor the diagnosis of germ cell tumors. Spheric shape without infundibular infiltration provides clues to papillary craniopharyngiomas, which originate from the pars tuberalis and are located outside the third ventricle. We suggest that suprasellar germ cell tumor is possibly an intraventricular lesion. Appropriate treatment planning can be initiated according to the diagnosis and anatomic location.

Except for pituitary macroadenoma, suprasellar tumors are infrequent in adult patients. Some of these suprasellar tumors have specific clinical and imaging features that make them straightforward to diagnose and subsequently manage. These classic features include a dural tail appearance in meningioma; young age; cysts and calcifications in adamantinomatous craniopharyngioma; homogeneous infiltrating mass of hypothalamic/optic pathway gliomas; a midline enhancing lesion in germ cell tumor (GCT); specific locations with signal similar to those of gray matter in hamartoma; and bright signals on DWI in epidermoids.^1–3 However, some suprasellar tumors in adults can mimic each other in some clinical and imaging features, making pretreatment planning difficult.Papillary craniopharyngiomas (PCPs) and GCTs are 2 unusual suprasellar tumors in adults, with similar clinical and imaging findings in some aspects. Clinically, PCPs and GCTs mostly occur in young adults with visual impairment or pituitary axis dysfunction or diabetes insipidus. They commonly present as predominantly solid or mixed cysts and solid suprasellar lesions with contrast enhancement on MR imaging. However, the treatment and outcomes of both tumor types are quite different.^2,4,5 Surgical resection not only is the main treatment of PCPs but also remarkably affects the outcome.⁶ By contrast, complete surgical resection is usually unnecessary in patients with germinoma. This radiosensitive tumor can be well-controlled by radiation therapy alone or combined with chemotherapy, even without a tissue diagnosis.⁷ The preoperative diagnosis of these 2 unusual suprasellar tumors in adults facilitates appropriate treatment planning and avoids associated surgical morbidity. We presumed that the distinct embryology and pathogenesis of the 2 tumors develop unique clinical and MR imaging characteristics. This study was designed to evaluate retrospectively the clinical and MR imaging findings of suprasellar papillary craniopharyngioma and germ cell tumors in adult patients, to obtain a pretreatment diagnosis.     

Subtraction MR Venography Acquired from Time-Resolved Contrast-Enhanced MR Angiography: Comparison with Phase-Contrast MR Venography and Single-Phase Contrast-Enhanced MR Venography

ObjectiveTo evaluate the image characteristics of subtraction magnetic resonance venography (SMRV) from time-resolved contrast-enhanced MR angiography (TRMRA) compared with phase-contrast MR venography (PCMRV) and single-phase contrast-enhanced MR venography (CEMRV).ResultsSingle-phase contrast-enhanced MR venography showed better image quality (median score 4 in both reviewers) than did the other two MRVs (p < 0.001), whereas SMRV (median score 3 in both reviewers) and PCMRV (median score 3 in both reviewers) had similar image quality (p ≥ 0.951). SMRV (median score 0 in both reviewers) suppressed arterial signal better than did the other MRVs (median score 1 in CEMRV, median score 2 in PCMRV, both reviewers) (p < 0.001). The dural sinus score of SMRV (median and interquartile range [IQR] 48, 43-50 for reviewer 1, 47, 43-49 for reviewer 2) was significantly higher than for PCMRV (median and IQR 31, 25-34 for reviewer 1, 30, 23-32 for reviewer 2) (p < 0.01) and did not differ from that of CEMRV (median and IQR 50, 47-52 for reviewer 1, 49, 45-51 for reviewer 2) (p = 0.146 in reviewer 1 and 0.123 in reviewer 2). The SNR and CNR of SMRV (median and IQR 104.5, 83.1-121.2 and 104.1, 74.9-120.5, respectively) were between those of CEMRV (median and IQR 150.3, 111-182.6 and 148.4, 108-178.2) and PCMRV (median and IQR 59.4, 49.2-74.9 and 53.6, 43.8-69.2).ConclusionSubtraction magnetic resonance venography is a promising MRV method, with acceptable image quality and good arterial suppression.     

Neurosyphilis in HIV-positive and HIV-negative patients: neuroimaging findings.

PURPOSETo evaluate and describe the neuroimaging findings of patients with neurosyphilis.METHODSThe neuroimaging studies of 35 patients with documented neurosyphilis were reviewed. Diagnosis was established in 34 patients with cerebrospinal fluid for a Venereal Disease Research Laboratory test, complemented by autopsy in 1 and brain biopsy in 1. All patients had reactive fluorescent treponemal antibody tests with absorption in their sera. Imaging studies included plain and contrast-enhanced CT of the brain, plain and gadolinium-enhanced MR, MR angiography, and conventional angiography. Imaging findings were also correlated with the relevant pathologic findings at autopsy in three additional patients with neurosyphilis who did not have brain imaging studies.RESULTSOf the 35 patients with imaging studies, 32 tested human immunodeficiency virus (HIV)-seropositive, and 3 were HIV-seronegative. Eleven (31%) of 35 patients had normal radiographic findings. Cerebral infarctions were seen in 8 (23%) of 35 patients, and nonspecific white matter lesions in 7 (20%) of 35. Cerebral gummas and extraaxial enhancement indicating meningitis were noted in 2 (6%) of 35 patients, respectively. Arteritis was demonstrated in 2 (50%) of 4 patients who underwent either MR angiography or conventional angiography. The 3 subjects who had autopsy but not imaging studies were found to have manifestations of meningovascular syphilis, including syphilitic leptomeningitis and an obliterative endarteritis.CONCLUSIONWe conclude that findings of vascular occlusive disease manifested as infarction or arteritis, enhancing cortical lesions with or without adjacent meningeal enhancement, focal or diffuse extraaxial enhancement, and white matter disease, although nonspecific, in the proper clinical setting should prompt appropriate testing for neurosyphilis, a treatable disease, in patients with and without HIV infection.     

Clinically Available Software for Automatic Brain Volumetry: Comparisons of Volume Measurements and Validation of Intermethod Reliability

ObjectiveTo compare two clinically available MR volumetry software, NeuroQuant® (NQ) and Inbrain® (IB), and examine the inter-method reliabilities and differences between them.Materials and MethodsThis study included 172 subjects (age range, 55–88 years; mean age, 71.2 years), comprising 45 normal healthy subjects, 85 patients with mild cognitive impairment, and 42 patients with Alzheimer''s disease. Magnetic resonance imaging scans were analyzed with IB and NQ. Mean differences were compared with the paired t test. Inter-method reliability was evaluated with Pearson''s correlation coefficients and intraclass correlation coefficients (ICCs). Effect sizes were also obtained to document the standardized mean differences.ResultsThe paired t test showed significant volume differences in most regions except for the amygdala between the two methods. Nevertheless, inter-method measurements between IB and NQ showed good to excellent reliability (0.72 < r < 0.96, 0.83 < ICC < 0.98) except for the pallidum, which showed poor reliability (left: r = 0.03, ICC = 0.06; right: r = −0.05, ICC = −0.09). For the measurements of effect size, volume differences were large in most regions (0.05 < r < 6.15). The effect size was the largest in the pallidum and smallest in the cerebellum.ConclusionComparisons between IB and NQ showed significantly different volume measurements with large effect sizes. However, they showed good to excellent inter-method reliability in volumetric measurements for all brain regions, with the exception of the pallidum. Clinicians using these commercial software should take into consideration that different volume measurements could be obtained depending on the software used.     

MR of pediatric intracranial meningiomas.

PURPOSETo assess MR and pathologic characteristics of childhood intracranial meningiomas, comparing the radiographic findings with those observed in adult intracranial meningiomas.METHODSClinical records, MR and CT scans, and histology of eight children with intracranial meningiomas presenting for a period of 7.5 years were retrospectively reviewed.RESULTSBoys equaled girls but predominated from ages 4 to 11 years. The ages ranged from 4 to 18 years. Two patients had radiation-induced meningiomas. Two children had multiple lesions; neither had neurofibromatosis. All solitary lesions were supratentorial. Other characteristics included: dural-based attachment (n = 6); large size (> 5 cm) (n = 4); cystic components (n = 3); and intraventricular location (n = 1). Histologic subtypes were: meningothelial (n = 4); transitional (n = 3); and fibroblastic (n = 1). Preoperative diagnoses of meningiomas were made in six cases based on overall imaging characteristics.CONCLUSIONSDiagnosis of childhood intracranial meningiomas does not differ from that of adults radiographically, with the exception of larger tumor sizes.     

Minimizing table time in patients with claustrophobia using focused ferumoxytol-enhanced MR angiography (f-FEMRA): a feasibility study

Objectives:To assess the feasibility of a rapid, focused ferumoxytol-enhanced MR angiography (f-FEMRA) protocol in patients with claustrophobia.Methods:In this retrospective study, 13 patients with claustrophobia expressed reluctance to undergo conventional MR angiography, but agreed to a trial of up to 10 min in the scanner bore and underwent f-FEMRA. Thirteen matched control patients who underwent gadolinium-enhanced MR angiography (GEMRA) were identified for comparison of diagnostic image quality. For f-FEMRA, the time from localizer image acquisition to completion of the angiographic acquisition was measured. Two radiologists independently scored images on both f-FEMRA and GEMRA for arterial and venous image quality, motion artefact and diagnostic confidence using a 5-point scale, five being best. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in the aorta and IVC were measured. The Wilcoxon rank-sum test, one-way ANOVA with Tukey correction and two-tailed t tests were utilized for statistical analyses.Results:All scans were diagnostic and assessed with high confidence (scores ≥ 4). Average scan time for f-FEMRA was 6.27 min (range 3.56 to 10.12 min), with no significant difference between f-FEMRA and GEMRA in diagnostic confidence (4.86 ± 0.24 vs 4.69 ± 0.25, p = 0.13), arterial image quality (4.62 ± 0.57 vs 4.65 ± 0.49, p = 0.78) and motion artefact score (4.58 ± 0.49 vs 4.58 ± 0.28, p > 0.99). f-FEMRA scored significantly better for venous image quality than GEMRA (4.62 ± 0.42 vs 4.19 ± 0.56, p = 0.04). CNR in the IVC was significantly higher for steady-state f-FEMRA than GEMRA regardless of the enhancement phase (p < 0.05).Conclusions:Comprehensive vascular MR imaging of the thorax, abdomen and pelvis can be completed in as little as 5 min within the magnet bore using f-FEMRA, facilitating acceptance by patients with claustrophobia and streamlining workflow.Advances in knowledge:A focused approach to vascular imaging with ferumoxytol can be performed in patients with claustrophobia, limiting time in the magnet bore to 10 min or less, while acquiring fully diagnostic images of the thorax, abdomen and pelvis.     

Effect of Papillary Muscles and Trabeculae on Left Ventricular Measurement Using Cardiovascular Magnetic Resonance Imaging in Patients with Hypertrophic Cardiomyopathy

ObjectiveTo evaluate the influence of papillary muscles and trabeculae on left ventricular (LV) cardiovascular magnetic resonance (CMR) analysis using three methods of cavity delineation (classic or modified inclusion methods, and the exclusion method) in patients with hypertrophic cardiomyopathy (HCM).ResultsMethod A showed larger end-diastole and end-systole volumes (largest percentage differences of 25% and 68%, respectively, p < 0.05), compared with method C. The ejection fraction was 55.7 ± 6.9% for method A, 68.6 ± 8.4% for B, and 71.7 ± 7.0% for C (p < 0.001). Mean mass was also significantly different: 164.6 ± 47.4 g for A, 176.5 ± 50.5 g for B, and 199.6 ± 53.2 g for C (p < 0.001). LV-SV error was largest with method B (p < 0.001). No difference in interobserver agreement was observed (p > 0.05).ConclusionIn HCM patients, LV measurements are strikingly different dependent on whether papillary muscles and trabeculae are included or excluded. Therefore, a consistent method of LV cavity delineation may be crucial during longitudinal follow-up to avoid misinterpretation and erroneous clinical decision-making.     

Usefulness of Silent MRA for Evaluation of Aneurysm after Stent-Assisted Coil Embolization

ObjectiveTo determine the usefulness of Silent MR angiography (MRA) for evaluating intracranial aneurysms treated with stent-assisted coil embolization.Materials and MethodsNinety-nine patients (101 aneurysms) treated with stent-assisted coil embolization (Neuroform atlas, 71 cases; Enterprise, 17; LVIS Jr, 9; and Solitaire AB, 4 cases) underwent time-of-flight (TOF) MRA and Silent MRA in the same session using a 3T MRI system within 24 hours of embolization. Two radiologists independently interpreted both MRA images retrospectively and rated the image quality using a 5-point Likert scale. The image quality and diagnostic accuracy of the two modalities in the detection of aneurysm occlusion were further compared based on the stent design and the site of aneurysm.ResultsThe average image quality scores of the Silent MRA and TOF MRA were 4.38 ± 0.83 and 2.78 ± 1.04, respectively (p < 0.001), with an almost perfect interobserver agreement. Silent MRA had a significantly higher image quality score than TOF MRA at the distal internal carotid artery (n = 57, 4.25 ± 0.91 vs. 3.05 ± 1.16, p < 0.001), middle cerebral artery (n = 21, 4.57 ± 0.75 vs. 2.19 ± 0.68, p < 0.001), anterior cerebral artery (n = 13, 4.54 ± 0.66 vs. 2.46 ± 0.66, p < 0.001), and posterior circulation artery (n = 10, 4.50 ± 0.71 vs. 2.90 ± 0.74, p = 0.013). Silent MRA had superior image quality score to TOF MRA in the stented arteries when using Neuroform atlas (4.66 ± 0.53 vs. 3.21 ± 0.84, p < 0.001), Enterprise (3.29 ± 1.59 vs. 1.59 ± 0.51, p = 0.003), LVIS Jr (4.33 ± 1.89 vs. 1.89 ± 0.78, p = 0.033), and Solitaire AB stents (4.00 ± 2.25 vs. 2.25 ± 0.96, p = 0.356). The interpretation of the status of aneurysm occlusion exhibited significantly higher sensitivity with Silent MRA than with TOF MRA when using the Neuroform Atlas stent (96.4% vs. 14.3%, respectively, p < 0.001) and LVIS Jr stent (100% vs. 20%, respectively, p = 0.046).ConclusionSilent MRA can be useful to evaluate aneurysms treated with stent-assisted coil embolization, regardless of the aneurysm location and type of stent used.     

Cerebral MR spectroscopy in neurologically asymptomatic HIV-infected patients

PURPOSE: To detect early metabolic changes in the brain of neurologically asymptomatic HIV-infected patients with normal MR imaging and to find the correlation between 1H MR results and immune status. MATERIAL AND METHODS: Twenty neurologically asymptomatic HIV seropositive patients underwent MR imaging and single-voxel 1H MR spectroscopy (MRS) using a PRESS sequence. For all patients, the signals from N-acetyl-aspartate (NAA), choline-containing compounds (Cho), creatine-phosphocreatine (Cr) and myoinositol (mI) were compared with 32 healthy volunteers as metabolite ratios and metabolite areas to non-suppressed water area ratios. RESULTS: In HIV patients, the NAA/Cho ratio was significantly lower ( p < 0.01), but there were no changes in NAA/Cr ratio. A statistically significant reduction in NAA/H2O and Cr/H2O (both p < 0.05) was observed. For the immune status there was a statistically significant correlation (r=0.47, p<0.05) between CD4 counts and NAA/H2O ratio. A significant increase in Cho/Cr ( p<0.001) and mI/Cr ( p<0.01) ratios in HIV patients was found, but Cho/H2O and mI/H2O concentrations were non-significantly increased. CONCLUSION: These results indicate that neuronal loss and gliosis in HIV-infected patients may be associated with impairment of energy metabolism. The spectral changes found suggest that 1H MRS can be used for early detection of brain damage induced by HIV.     

Free-Breathing Motion-Corrected Single-Shot Phase-Sensitive Inversion Recovery Late-Gadolinium-Enhancement Imaging: A Prospective Study of Image Quality in Patients with Hypertrophic Cardiomyopathy

ObjectiveMotion-corrected averaging with a single-shot technique was introduced for faster acquisition of late-gadolinium-enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging while free-breathing. We aimed to evaluate the image quality (IQ) of free-breathing motion-corrected single-shot LGE (moco-ss-LGE) in patients with hypertrophic cardiomyopathy (HCM).Materials and MethodsBetween April and December 2019, 30 patients (23 men; median age, 48.5; interquartile range [IQR], 36.5–61.3) with HCM were prospectively enrolled. Breath-held single-shot LGE (bh-ss-LGE) and free-breathing moco-ss-LGE images were acquired in random order on a 3T MR system. Semi-quantitative IQ scores, contrast-to-noise ratios (CNRs), and quantitative size of myocardial scar were assessed on pairs of bh-ss-LGE and moco-ss-LGE. The mean ± standard deviation of the parameters was obtained. The results were compared using the Wilcoxon signed-rank test.ResultsThe moco-ss-LGE images had better IQ scores than the bh-ss-LGE images (4.55 ± 0.55 vs. 3.68 ± 0.45, p < 0.001). The CNR of the scar to the remote myocardium (34.46 ± 11.85 vs. 26.13 ± 10.04, p < 0.001), scar to left ventricle (LV) cavity (13.09 ± 7.95 vs. 9.84 ± 6.65, p = 0.030), and LV cavity to remote myocardium (33.12 ± 15.53 vs. 22.69 ± 11.27, p < 0.001) were consistently greater for moco-ss-LGE images than for bh-ss-LGE images. Measurements of scar size did not differ significantly between LGE pairs using the following three different quantification methods: 1) full width at half-maximum method; 23.84 ± 12.88% vs. 24.05 ± 12.81% (p = 0.820), 2) 6-standard deviation method, 15.14 ± 10.78% vs. 15.99 ± 10.99% (p = 0.186), and 3) 3-standard deviation method; 36.51 ± 17.60% vs. 37.50 ± 17.90% (p = 0.785).ConclusionMotion-corrected averaging may allow for superior IQ and CNRs with free-breathing in single-shot LGE imaging, with a herald of free-breathing moco-ss-LGE as the scar imaging technique of choice for clinical practice.     

Progressive multifocal leukoencephalopathy and human immunodeficiency virus-associated white matter lesions in AIDS: magnetization transfer MR imaging

PURPOSE: To determine the magnetization transfer features of progressive multifocal leukoencephalopathy (PML) and human immunodeficiency virus (HIV)-associated white matter lesions (WML) (hereafter, HIV-WML) on magnetic resonance (MR) images obtained in patients with acquired immunodeficiency syndrome (AIDS). MATERIALS AND METHODS: Conventional MR imaging and magnetization transfer MR imaging were performed in 21 AIDS patients with 42 areas of white matter hyperintensity on MR images (13 patients had 25 PML lesions, eight patients had 17 WML). The magnetization transfer ratio was calculated for each lesion. RESULTS: Compared with normal-appearing white matter (magnetization transfer ratio = 47.9%), both PML and HIV-WML showed reduced magnetization transfer ratio. The magnetization transfer ratio was significantly lower in PML lesions (magnetization transfer ratio = 26.1%) than in HIV-WML (magnetization transfer ratio = 38.0%, P < .0001), and there was no overlap in the magnetization transfer ratio between PML lesions and HIV-WML. The separation in magnetization transfer ratio between the two lesion types was valid for lesion as small as 0.5 cm2. CONCLUSION: The larger reduction in magnetization transfer ratio for PML lesions is most likely due to demyelination, whereas the reduction in HIV-WML may be associated primarily with gliosis. PML lesions appear to cause strong reductions in magnetization transfer ratio early in the course of disease. Magnetization transfer MR imaging is a noninvasive tool that improves the differentiation between PML and HIV-WML in patients with AIDS.     

Liver-to-Spleen Volume Ratio Automatically Measured on CT Predicts Decompensation in Patients with B Viral Compensated Cirrhosis

ObjectiveAlthough the liver-to-spleen volume ratio (LSVR) based on CT reflects portal hypertension, its prognostic role in cirrhotic patients has not been proven. We evaluated the utility of LSVR, automatically measured from CT images using a deep learning algorithm, as a predictor of hepatic decompensation and transplantation-free survival in patients with hepatitis B viral (HBV)-compensated cirrhosis.Materials and MethodsA deep learning algorithm was used to measure the LSVR in a cohort of 1027 consecutive patients (mean age, 50.5 years; 675 male and 352 female) with HBV-compensated cirrhosis who underwent liver CT (2007–2010). Associations of LSVR with hepatic decompensation and transplantation-free survival were evaluated using multivariable Cox proportional hazards and competing risk analyses, accounting for either the Child-Pugh score (CPS) or Model for End Stage Liver Disease (MELD) score and other variables. The risk of the liver-related events was estimated using Kaplan-Meier analysis and the Aalen-Johansen estimator.ResultsAfter adjustment for either CPS or MELD and other variables, LSVR was identified as a significant independent predictor of hepatic decompensation (hazard ratio for LSVR increase by 1, 0.71 and 0.68 for CPS and MELD models, respectively; p < 0.001) and transplantation-free survival (hazard ratio for LSVR increase by 1, 0.8 and 0.77, respectively; p < 0.001). Patients with an LSVR of < 2.9 (n = 381) had significantly higher 3-year risks of hepatic decompensation (16.7% vs. 2.5%, p < 0.001) and liver-related death or transplantation (10.0% vs. 1.1%, p < 0.001) than those with an LSVR ≥ 2.9 (n = 646). When patients were stratified according to CPS (Child-Pugh A vs. B–C) and MELD (< 10 vs. ≥ 10), an LSVR of < 2.9 was still associated with a higher risk of liver-related events than an LSVR of ≥ 2.9 for all Child-Pugh (p ≤ 0.045) and MELD (p ≤ 0.009) stratifications.ConclusionThe LSVR measured on CT can predict hepatic decompensation and transplantation-free survival in patients with HBV-compensated cirrhosis.