T2 Signal Ratio Research Articles

In utero exposure to maternal diabetes or hypertension and childhood hypothalamic gliosis.

Exposure to maternal diabetes (DM) or hypertension (HTN) during pregnancy impacts offspring metabolic health in childhood and beyond. Animal models suggest that induction of hypothalamic inflammation and gliosis in the offspring's hypothalamus is a possible mechanism mediating this effect. We tested, in children, whether in utero exposures to maternal DM or HTN were associated with mediobasal hypothalamic (MBH) gliosis as assessed by brain magnetic resonance imaging (MRI). The study included a subsample of 306 children aged 9-11 years enrolled in the ABCD Study®; 49 were DM-exposed, 53 were HTN-exposed, and 204 (2:1 ratio) were age- and sex-matched children unexposed to DM and/or HTN in utero. We found a significant overall effect of group for the primary outcome of MBH/amygdala (AMY) T2 signal ratio (F(2,300):3.51, p = 0.03). Compared to unexposed children, MBH/AMY T2 signal ratios were significantly higher in the DM-exposed (β:0.05, p = 0.02), but not the HTN-exposed children (β:0.03, p = 0.13), findings that were limited to the MBH and independent of adiposity. We concluded that children exposed to maternal DM in utero display evidence of hypothalamic gliosis, suggesting that gestational DM may have a distinct influence on offspring's brain development and, by extension, children's long-term metabolic health.

A magnetic resonance enterography index for assessing small bowel Crohn's disease activity.

This study aimed to construct a magnetic resonance imaging (MRI) index for assessing transmural inflammatory activity in the small intestine of patients with Crohn' disease which enables rapid and non-invasive quantitative assessment of Crohn's disease inflammation. In this prospective study, magnetic resonance enterography (MRE) was performed to examine 29 consecutive patients with Crohn's disease who had undergone ileocolonoscopy in the Jingling hospital of Nanjing. This diagnostic study was not registered on a clinical trial platform. We grade the T2 signal ratio and T1 enhancement ratio with a score of 0 to 3. The ratios were calculated as follow: terminal ileal inflammation of intestinal T2 signal intensity/adjacent normal intestinal T2 signal intensity (T2 ratio 1), terminal ileal inflammation intestinal T2 signal intensity/vertical muscle T2 signal intensity (T2 ratio 2), the fifth phase of the inflamed intestinal T1 signal intensity/noncontrast intestine T1 signal (T1 ratio 3), and the fifth phase of inflamed intestinal T1 signal intensity/adjacent normal intestinal T1 signal (T1 ratio 4). Wall thickness, lymph nodes, perimural T2 signal, comb sign, and ulceration were graded from 0 to 3. the simple endoscopic score for Crohn's disease (SES-CD) from 0 to 12 was used to assess Crohn's disease activity as a reference. The study calculated the correlations between the MRE activity index and endoscopic activity scores and derived the MRE index model to assess Crohn's disease activity. The MRE index model (a T1 ratio 4 score of 1.52 + an ulceration score of 2.03) had a sensitivity of 0.962, a specificity of 0.667, and an area under the curve (AUC) of 0.968 [95% confidence interval (CI): 0.921-1.000]. The intraclass correlation coefficient (ICC) for the interobserver agreement of the MRE index was 0.921 (95% CI: 0.833-0.963). The study derived an MRE index with good sensitivity to inflammatory changes in the small bowel. The index could be used to assess Crohn's disease activity of the small bowel.

343-OR: Maternal Diabetes Is Associated with Hypothalamic Gliosis in Offspring

In utero exposure to gestational diabetes (GDM) or hypertension (HYP) is associated with child obesity. These maternal conditions alter the in utero milieu and may predispose offspring to obesity via an effect on the brain. Cellular inflammation (gliosis) in the mediobasal hypothalamus (MBH) has been associated with child and adult obesity and type 2 diabetes in adults. We evaluated the brain MRIs of offspring exposed to GDM or HYP during gestation for evidence of MBH gliosis. This case-control study included a subsample of 3child participants (9-11y) in the NIH ABCD study. Baseline T2-weighted MRI scans were analyzed for evidence of MBH gliosis (high MBH T2 signal) based on the mean bilateral MBH/Amygdala (AMY) T2 signal ratio. Putamen (PUT) /AMY and MBH/PUT were negative and positive control ratios, respectively. Findings from 49 children exposed to GDM and 53 exposed to HYP (by pregnancy survey) were contrasted to 2age- and sex-matched controls (healthy pregnancy) . Baseline, 1y and 2y follow-up anthropometrics were available. At baseline, groups did not differ on age, sex, race, and socioeconomic status. GDM group had more Hispanic children and higher birth weight than controls and HYP. Offspring exposed to GDM or HYP had higher BMI z-score, % of BMI 95th percentile, and waist/height ratio than controls at all time points (all P<0.01) . Overall, there were significant group differences in MBH/AMY signal ratio (F (2,294) :355, P=0.03, adjusted for site, age, sex and ethnicity) . Specifically, compared to controls, GDM-exposed offspring, but not HYP, had higher MBH/AMY signal ratio (GDM β:0.05, P=0.02; HYP β:0.03, P=0.11) . The results persisted when further adjusted for baseline BMI z-score (GDM β:0.04, P=0.03) . Results were replicated with the positive control ratio, but not the negative control ratio. GDM-exposed offspring have greater evidence of MBH gliosis, independent of body adiposity. This could represent one pathway by which the in utero environment may impact offspring’s future metabolic health. Disclosure L.E.Sewaybricker: None. K.Olerich: None. S.L.Kee: None. S.J.Melhorn: None. S.Chandrasekaran: None. E.Schur: None. Funding National Institutes of Health (R01DK117623)

Evaluation of intervertebral disc degeneration using T2 signal ratio on magnetic resonance imaging

PurposeIntervertebral disc degeneration is assessed clinically by magnetic resonance imaging (MRI). Although some quantitative evaluation methods for MRI under special imaging conditions have been reported, they are widely and generally difficult to use. The aim of this study is to determine if intervertebral disc degeneration can be assessed using the ratio of MRI T2 values of the disc to the spinal cord T2 values. MethodsSignal ratio was calculated using the T2 signal intensity of the disc and the spinal cord on MRI under common conditions for a new assessment of disc degeneration. T2-weighted images of 100 patients undergoing MRI twice within a year under different imaging conditions, 1.5 T or less and 3.0 T, were used for the assessment. The T2 signal intensity was measured at the center of the discs at L2-3, L3-4, L4-5, L5-S1 and the spinal cord at T12 level. Signal ratio was calculated using these T2 signal intensity values. The ratio of the difference between the first and second values to the mean of the first and second values was calculated to confirm the equivalence of MRI assessments of disc degeneration in the same patient under different imaging conditions. ResultsThe equivalence of values between the first MRI and the second MRI in the signal ratio was significantly higher than that in the T2 signal intensity. In addition, the signal ratio was negatively correlated with age and were significantly associated with Pfirrmann grade. ConclusionsBy using the signal ratio, disc degeneration can be evaluated by MRI even under different imaging conditions.

Cardiovascular Magnetic Resonance Detects Inflammatory Cardiomyopathy in Symptomatic Patients with Inflammatory Joint Diseases and a Normal Routine Workup.

Background. Patients with inflammatory joint diseases (IJD) are more likely to develop cardiovascular disease compared with the general population. We hypothesized that cardiovascular magnetic resonance (CMR) could identify cardiac abnormalities in patients with IJD and atypical symptoms unexplained by routine clinical evaluation. Patients-Methods. A total of 51 consecutive patients with IJD (32 with rheumatoid arthritis, 10 with ankylosing spondylitis, and 9 with psoriatic arthritis) and normal clinical, electrocardiographic and echocardiographic workups, were referred for CMR evaluation due to atypical chest pain, shortness of breath, and/or palpitations. Their CMR findings were compared with those of 40 non-IJD controls who were referred for the same reason. All participants were examined using either a 1.5 T or 3.0 T CMR system. For T1/T2 mapping, comparisons were performed separately for each field strength. Results. Biventricular systolic function was similar between groups. In total, 25 (49%) patients with IJD vs. 0 (0%) controls had replacement-type myocardial fibrosis (p < 0.001). The T2 signal ratio, early/late gadolinium enhancement, and extracellular volume fraction were significantly higher in the IJD group. Native T1 mapping was significantly higher in patients with IJD independent of the MRI field strength (p < 0.001 for both). T2 mapping was significantly higher in patients with IJD compared with controls only in those examined using a 1.5 T MR system—52.0 (50.0, 55.0) vs. 37.0 (33.5, 39.5), p < 0.001. Conclusions. In patients with IJD and a mismatch between cardiac symptoms and routine non-invasive evaluation, CMR uniquely identified a significant proportion of patients with myocardial inflammation. A CMR examination should be considered in patients with IJD in similar clinical settings.

Diagnostic value of gadolinium contrast administration for spinal cord magnetic resonance imaging in multiple sclerosis patients and correlative markers of lesion enhancement

BackgroundMagnetic resonance imaging is essential for monitoring people with multiple sclerosis, but the diagnostic value of gadolinium contrast administration in spine magnetic resonance imaging is unclear.ObjectiveTo assess the diagnostic value of gadolinium contrast administration in spine magnetic resonance imaging follow-up examinations and identify imaging markers correlating with lesion enhancement.MethodsA total of 65 multiple sclerosis patients with at least 2 spinal magnetic resonance imaging follow-up examinations were included. Spine magnetic resonance imaging was performed at 3 Tesla with a standardized protocol (sagittal and axial T2-weighted turbo spin echo and T1-weighted post-contrast sequences). T2 lesion load and enhancing lesions were assessed by two independent neuroradiologists for lesion size, localization, and T2 signal ratio (T2 signallesion/T2 signalnormal appearing spinal cord).ResultsA total of 68 new spinal T2 lesions and 20 new contrast-enhancing lesions developed during follow-up. All enhancing lesions had a discernable correlate as a new T2 lesion. Lesion enhancement correlated with a higher T2 signal ratio compared to non-enhancing lesions (T2 signal ratio: 2.0 ± 0.4 vs. 1.4 ± 0.2, ****p < 0.001). Receiver operating characteristics analysis showed an optimal cutoff value of signal ratio 1.78 to predict lesion enhancement (82% sensitivity and 97% specificity).ConclusionGadolinium contrast administration is dispensable in follow-up spine magnetic resonance imaging if no new T2 lesions are present. Probability of enhancement correlates with the T2 signal ratio.

Magnetic Resonance Prediction of Lung Maturity in Fetuses With Congenital Diaphragmatic Hernia.

To determine if lung to liver MR T2 signal ratio is predictive of neonatal outcome in fetuses with congenital diaphragmatic hernia (CDH).After Interal Review Board approval, the PACS systems at the University of Washington and University of Utah were searched for cases having an in utero fetal MR examination diagnostic of CDH. Inclusion criteria were at least 1 prior ultrasound demonstrating a CDH and an MR obtained within 1 week of that prior ultrasound.A total of 69 patients from the University of Utah and 13 from the University of Washington satisfied the inclusion criteria for a total of 82. After adjusting for gestational age and contralateral lung volume, there was little apparent association between contralateral lung to liver MR T2 signal and 5-minute Apgar score and neonatal mortality When considering neonatal Apgar and mortality, increasing contralateral lung volume was significantly associated with lower risk (hazard ratio, 0.40 per doubling; 95% confidence interval, 0.24-0.69; P = 0.001) as expected.Our data demonstrate that the lung to liver MR signal ratio was not predictive of outcome. The measurement of contralateral lung area, and gestational age at the time of the examination (time of diagnosis) are still the best predictors of poor neonatal outcome.

Ventricular Tachycardia Has Mainly Non-Ischaemic Substrates in Patients with Autoimmune Rheumatic Diseases and a Preserved Ejection Fraction.

Non-sustained ventricular tachycardia (NSVT) is a potentially lethal arrhythmia that is most commonly attributed to coronary artery disease. We hypothesised that among patients with NSVT and preserved ejection fraction, cardiovascular magnetic resonance (CMR) would identify a different proportion of ischaemic/non-ischaemic arrhythmogenic substrates in those with and without autoimmune rheumatic diseases (ARDs). In total, 80 consecutive patients (40 with ARDs, 40 with non-ARD-related cardiac pathology) with NSVT in the past 15 days and preserved left ventricular ejection fraction were examined using a 1.5-T system. Evaluated parameters included biventricular volumes/ejection fractions, T2 signal ratio, early/late gadolinium enhancement (EGE/LGE), T1 and T2 mapping and extracellular volume fraction (ECV). Mean age did not differ across groups, but patients with ARDs were more often women (32 (80%) vs. 15 (38%), p < 0.001). Biventricular systolic function, T2 signal ratio and EGE and LGE extent did not differ significantly between groups. Patients with ARDs had significantly higher median native T1 mapping (1078.5 (1049.0–1149.0) vs. 1041.5 (1014.0–1079.5), p = 0.003), higher ECV (31.0 (29.0–32.0) vs. 28.0 (26.5–30.0), p = 0.003) and higher T2 mapping (57.5 (54.0–61.0) vs. 52.0 (48.0–55.5), p = 0.001). In patients with ARDs, the distribution of cardiac fibrosis followed a predominantly non-ischaemic pattern, with ischaemic patterns being more common in those without ARDs (p < 0.001). After accounting for age and cardiovascular comorbidities, most findings remained unaffected, while only tissue characterisation indices remained significant after additionally correcting for sex. Patients with ARDs had a predominantly non-ischaemic myocardial scar pattern and showed evidence of diffuse inflammatory/ischaemic changes (elevated native T1-/T2-mapping and ECV values) independent of confounding factors.

The Doubled-Edged Sword of T1-Mapping in Systemic Sclerosis-A Comparison with Infectious Myocarditis Using Cardiovascular Magnetic Resonance.

Aims: T1-mapping is considered a surrogate marker of acute myocardial inflammation. However, in diffuse cutaneous systemic sclerosis (dcSSc) this might be confounded by coexisting myocardial fibrosis. We hypothesized that T1-based indices should not by themselves be considered as indicators of myocardial inflammation in dcSSc patients. Methods/Results: A cohort of 59 dcSSc and 34 infectious myocarditis patients was prospectively evaluated using a 1.5-Tesla system for an indication of suspected myocardial inflammation and was compared with 31 healthy controls. Collectively, 33 (97%) and 57 (98%) of myocarditis and dcSSc patients respectively had ≥1 pathologic T2-based index. However, 33 (97%) and 45 (76%) of myocarditis and dcSSc patients respectively had ≥1 pathologic T2-based index. T2-signal ratio was significantly higher in myocarditis patients compared with dcSSc patients (2.5 (0.6) vs. 2.1 (0.4), p < 0.001). Early gadolinium enhancement, late gadolinium enhancement and T2-mapping did not differ significantly between groups. However, both native T1-mapping and extracellular volume fraction were significantly lower in myocarditis compared with dcSSc patients (1051.0 (1027.0, 1099.0) vs. 1120.0 (1065.0, 1170.0), p < 0.001 and 28.0 (26.0, 30.0) vs. 31.5 (30.0, 33.0), p < 0.001, respectively). The original Lake Louise criteria (LLc) were positive in 34 (100%) myocarditis and 40 (69%) dcSSc patients, while the updated LLc were positive in 32 (94%) and 44 (76%) patients, respectively. Both criteria had good agreement with greater but nonsignificant discordance in dcSSc patients. Conclusions: ~25% of dcSSc patients with suspected myocardial inflammation had no CMR evidence of acute inflammatory processes. T1-based indices should not be used by themselves as surrogates of acute myocardial inflammation in dcSSc patients.

Cardiovascular Magnetic Resonance Identifies High-Risk Systemic Sclerosis Patients with Normal Echocardiograms and Provides Incremental Prognostic Value.

Background: Acute cardiac events are a significant contributor to mortality in systemic sclerosis (SSc). However, echocardiographic evaluation may be deceptively normal during an acute presentation. We hypothesized that in diffuse SSc patients presenting with acute cardiac events and a normal echocardiogram, cardiovascular magnetic resonance (CMR) would have incremental diagnostic/prognostic value. Methods. 50 consecutive diffuse SSc patients with normal echocardiograms were evaluated using a 1.5T system. A total of 27 (63%) had experienced an acute cardiac event three to tendays before CMR evaluation (rhythm disturbances, angina pectoris, shortness of breath). Left/right ventricular (LV/RV) volumes and ejection fractions (EF), as well as LV mass, the T2-signal ratio, early/late gadolinium enhancement (EGE/LGE), native/post-contrast T1-mapping, T2-mapping and extracellular volume fraction (ECV) were compared between the event and no-event groups. Results: No differences were identified in LV/RV volumes/EF/mass. In logistic regression analyses, independent predictors of belonging to the event group were EGE (odds ratio (95% CI): 1.55 (1.06–2.26), p = 0.024), LGE (1.81 (1.23–2.67), p = 0.003), T2 mapping (1.20 (1.06–1.36), p = 0.004) and native/post-contrast T1 mapping (1.17 (1.04–1.32), p = 0.007 and 0.86 (0.75–0.98), p = 0.025). At a median follow-up of ~1.2 years, 42% vs. 11% of the event/no-event group respectively reached a combined endpoint of event occurrence/recurrence or cardiovascular mortality. Of the independent predictors resulting from logistic regression analyses, only LGE (hazard ratio (95% CI): 1.20 (1.11–1.30), p < 0.001), T2-mapping (1.07 (1.01–1.14), p = 0.025) and native T1-mapping (1.08 (1.01–1.15), p = 0.017) independently predicted the combined endpoint. Conclusions: A normal echocardiogram does not preclude myocardial lesions in diffuse SSc patients, which can be detected by CMR especially in symptomatic patients.

Value of imaging findings in predicting post‑operative recurrence of desmoid‑type fibromatosis

Desmoid-type fibromatosis is a rare type of soft-tissue tumor originating from connective tissue of the fascia or aponeurosis, which exhibits aggressive growth, high likelihood of relapse and less frequent distant metastasis. The present study aimed to predict the recurrence rate and time by retrospectively analyzing the clinical data (sex, age and recurrence time), imaging findings [tumor location, maximum diameter, border, computed tomography (CT) enhancement ratio, magnetic resonance enhancement ratio and T2 signal ratio] and pathological features (Ki-67 and microscopic margin) in a total of 102 cases of pathologically confirmed desmoid-type fibromatosis. The risk ratio of each factor was calculated using the Cox proportional hazards regression model and the cumulative recurrence-free survival rate was determined using the Kaplan-Meier method and the log-rank test. The cohort comprised of 73 females and 29 males, with mean age of 32.86±12.64 years (range, 6–78 years). The 1-year and 2-year recurrence rate was 31 and 54%, respectively. The median age at recurrence was 29 years. Univariate analysis indicated that sex, maximum tumor diameter, CT enhancement ratio and Ki-67 had a significant effect on the recurrence time. Furthermore, multivariate analysis revealed that sex, maximum tumor diameter, Ki-67 and T2 signal ratio were independently associated with the time of recurrence, and the risk ratios were 0.424, 1.100, 1.084 and 1.268, respectively. Therefore, in male patients with a larger maximum tumor diameter, positivity for Ki-67 and a higher T2 signal ratio, desmoid-type fibromatosis was more likely to recur after surgery.

Evidence-based MR imaging follow-up strategy for desmoid-type fibromatosis.

To propose a follow-up strategy for desmoid-type fibromatosis (DF) based on tumor growth behavior and the signal on T2-weighted MRI. We retrospectively reviewed 296 MRI studies of 34 patients with histologically proven DF. In each study, tumor volume and T2 signal relatively normal striated muscle were assessed. Volume variation and monthly growth rates were analyzed to determine lesion growth behavior (progressing versus stable/regressing lesions). Growth behavior was correlated with T2 signal, tumor location, β-catenin status, treatment strategy, and follow-up duration. Interobserver variability of volume measurements and interobserver measurement variation ratio were assessed. There were 25 women and 9 men with a mean age of 39.9 ± 19 (4-73) years. Mean follow-up time in the patients included was 55 ± 41 (12-148) months. In progressing lesions, the mean average monthly growth ratio was 10.9 ± 9.2 (1.1-42.5) %. Interobserver variability of volume measurements was excellent (ICC = 0.96). Mean interobserver measurement variation ratio was 20.4 ± 23.6%. The only factor correlated with tumor growth behavior was T2 signal ratio (p< 0.0001). Seventeen out of 34 (50%) patients presented a signal change over the threshold of 1 during follow-up. There were five occurrences of secondary growth after a period of stability with a mean delay until growth of 38.2 ± 44.2 (17-116) months. DF growth rate was quantitatively assessed. A threshold for volume variation detection was established. DF growth behavior was significantly related to T2 signal. An evidence-based follow-up strategy is proposed. • In progressing desmoid fibromatosis, the mean average monthly growth ratio was 10.9 ± 9.2%. • Lesions with muscle/tumor T2 signal ratios lower than 1 tended to be stable or regress over time. • Given the interobserver measurement variability and MRI in-plane spatial resolution, a variation higher than 42.6% in tumor volume is required to confirm punctual progression.

Natural History of Myocardial Injury and Chamber Remodeling in Acute Myocarditis.

Cardiovascular magnetic resonance (CMR) imaging is commonly used to diagnose acute myocarditis. However, the natural history of CMR-based tissue markers and their association with left ventricular recovery is poorly explored. We prospectively investigated the natural history of CMR-based myocardial injury and chamber remodeling over 12 months in patients with suspected acute myocarditis. One hundred patients with suspected acute myocarditis were enrolled. All underwent CMR evaluations at baseline and 12 months, inclusive of T2 and late gadolinium enhancement. Blinded quantitative analyses compared left ventricular chamber volumes, function, myocardial edema, and necrosis at each time point using predefined criteria. The predefined primary outcomes were improvement in left ventricular ejection fraction ≥10% and improvement in the indexed left ventricular end diastolic volume ≥10% at 12 months. The mean age was 39.9±14.5 years (82 male) with baseline left ventricular ejection fraction of 57.1±11.2%. A total of 72 patients (72%) showed late gadolinium enhancement at baseline with 57 (57%) having any T2 signal elevation. Left ventricular volumes and EF improved significantly at 12 months. Global late gadolinium enhancement extent dropped from 8.5±9.2% of left ventricular mass to 3.0±5.2% ( P=0.0001) with prevalence of any late gadolinium enhancement dropping to 48%. Reductions in global T2 signal ratio occurred at 12 months (1.85±0.3 to 1.56±0.2; P=0.0001) with prevalence of T2 ratio ≥2.0 dropping to 7%. Neither marker provided associations with the primary outcomes. In clinically suspected acute myocarditis, significant reductions in tissue injury markers occur during the first 12 months of convalescence. Neither the presence nor extent of the investigated CMR-based tissue injury markers were predictive of our pre-defined function or remodeling outcomes at 12 months in this referral population.

Cardiovascular magnetic resonance imaging pattern in patients with autoimmune rheumatic diseases and ventricular tachycardia with preserved ejection fraction

BackgroundVentricular tachycardia/fibrillation (VT/VF) may occur in autoimmune rheumatic diseases (ARDs). We hypothesized that cardiovascular magnetic resonance (CMR) can identify arrhythmogenic substrates in ARD patients. Patients - methodsUsing a 1.5 T system, we evaluated 61 consecutive patients with various types of ARDs and normal left ventricular ejection fraction (LVEF) on echocardiography. A comparison of patients with recent VT/VF and those that never experienced VT/VF was performed. CMR parameters included left and right ventricular (LV and RV) end-systolic and end-diastolic volumes (ESV and EDV), T2 signal ratio of myocardium over skeletal muscle, early/late gadolinium enhancement (EGE and LGE), T1/T2-mapping and extracellular volume fraction (ECV). Results21 (34%) patients had a history of recent, electrocardiographically identified, VT/VF. No demographic or functional CMR variables differed significantly between groups. The same was the case for T2 signal ratio and EGE/LGE. Median native T1 mapping values were significantly higher in patients with VT/VF compared to those without [1135.0 (1076.0, 1201.0) vs. 1050.0 (1025.0, 1078.0), p < 0.001], as was the case for mean T2 mapping [60.4 (6.6) vs. 55.0 (7.9), p = 0.009] and median ECV values [32.0 (30.0, 32.0) vs. 29.0 (28.0, 31.5), p = 0.001]. After multivariate corrections for age, LVEDV, LVEF, RVEDV, RVEF, T2 signal ratio, EGE and LGE, these remained significant predictors of having experienced VT/VF in the past. ConclusionsT1/T2-mapping and ECV offer incremental value as identifiers of arrhythmogenic substrates in ARD patients, beyond traditionally used indices. They can thus guide implantable cardiac defibrillator (ICD) implantation in ARD patients presenting with VT/VF and normal LVEF.

Gd contrast administration is dispensable in patients with MS without new T2 lesions on follow-up MRI.

ObjectiveTo assess the diagnostic value of gadolinium (Gd) contrast administration in MRI follow-up examinations of patients with MS if the T2 lesion load is stable.MethodsWe included 100 patients with MS with at least 2 cranial MRI follow-up examinations (mean follow-up time 4.0 ± 2.6 years). MRI was performed at 3 Tesla with a standardized protocol including T2-weighted, fluid-attenuated inversion recovery (FLAIR) and T1-weighted contrast-enhanced sequences. Images were analyzed for T2/FLAIR and contrast-enhancing (CE) lesions by 3 independent neuroradiologists. Isolated Gd-enhancing lesions without correlate in T2 and FLAIR images, and reactivated Gd+ lesions were further assessed for size and signal intensity.ResultsWe identified a total of 343 new T2 lesions and 152 CE lesions in a total of 559 MRI follow-up examinations. New T2/FLAIR lesions were present in 30% of the scans. Of the Gd-enhancing lesions, 145/152 (95.4%) showed a correlate as a new T2/FLAIR lesion. There were 3 enhancing lesions (1.9% of all enhancing lesions) without T2/FLAIR correlate and 4 lesions (2.6%) that exhibited lesion reactivation or persistent enhancement over time. As a predictive factor of enhancement, we found that enhancing lesions had a higher T2 signal ratio (T2 SRlesion/normal-appearing white matter: 3.0 ± 0.1 vs 2.2 ± 0.1, p < 0.001).ConclusionThe likelihood of missing “active lesions” is overall small (1.7%) if T2 lesions are stable compared with the previous MRI examination. Lesion reactivation is rare. Our study indicates that Gd contrast administration might be dispensable in follow-up MRI of patients with MS if no new T2/FLAIR lesions and no new neurologic symptoms are present.

Increased fetal lung T2 signal is not due to increasing surfactant concentration: an in vitro T2 mapping analysis.

The aim of this study was to perform in vitro T2 mapping of serial dilutions of pharmaceutical surfactant. Magnetic resonance imaging. Magnetic resonance scanning was performed on serial dilutions of surfactant on large bore clinical magnets at a field strength of 1.5 T Philips and 3.0 T (Achieva TX, Philips Healthcare, the Netherlands). The curves demonstrate a small increasing trend between surfactant concentration and R2 (shortened T2's), with a 7.3% increase in R2 for each doubling of surfactant concentration (95% confidence interval: 6.1-8.6%, p < 0.001). The increasing lung/liver T2 signal ratio seen in fetal lungs with increasing gestational age is not due to increasing surfactant concentration. © 2016 John Wiley & Sons, Ltd.

Uterine Fibroids: Correlation of T2 Signal Intensity with Semiquantitative Perfusion MR Parameters in Patients Screened for MR-guided High-Intensity Focused Ultrasound Ablation.

To evaluate the relationships between T2 signal intensity and semiquantitative perfusion magnetic resonance (MR) parameters of uterine fibroids in patients who were screened for MR-guided high-intensity focused ultrasound (HIFU) ablation. Institutional review board approval was granted, and informed consents were waived. One hundred seventy most symptom-relevant, nondegenerated uterine fibroids (mean diameter, 7.3 cm; range, 3.0-17.2 cm) in 170 women (mean age, 43.5 years; range, 24-56 years) undergoing screening MR examinations for MR-guided HIFU ablation from October 2009 to April 2014 were retrospectively analyzed. Fibroid signal intensity was assessed as the ratio of the fibroid T2 signal intensity to that of skeletal muscle. Parameters of semiquantitative perfusion MR imaging obtained during screening MR examination (peak enhancement, percentage of relative peak enhancement, time to peak [in seconds], wash-in rate [per seconds], and washout rate [per seconds]) were investigated to assess their relationships with T2 signal ratio by using multiple linear regression analysis. Correlations between T2 signal intensity and independently significant perfusion parameters were then evaluated according to fibroid type by using Spearman correlation test. Multiple linear regression analysis revealed that relative peak enhancement showed an independently significant correlation with T2 signal ratio (Β = 0.004, P < .001). Submucosal intracavitary (n = 20, ρ = 0.275, P = .240) and type III (n = 18, ρ = 0.082, P = .748) fibroids failed to show significant correlations between perfusion and T2 signal intensity, while significant correlations were found for all other fibroid types (ρ = 0.411-0.629, P < .05). In possible candidates for MR-guided HIFU ablation, the T2 signal intensity of nondegenerated uterine fibroids showed an independently significant positive correlation with relative peak enhancement in most cases, except those of submucosal intracavitary or type III fibroids.

Large vestibular schwannomas treated by Gamma Knife surgery: long-term outcomes

Although radiosurgery has been well accepted as a treatment for small- to medium-sized vestibular schwannomas (VSs), its application in the treatment of large VSs remains controversial because of unfavorable effects such as tumor swelling and potential compression of the brainstem. The authors present a retrospective study spanning 17 years, during which 21 patients underwent Gamma Knife surgery (GKS) for large VSs. Long-term outcomes are reported, and possible factors affecting tumor responses to GKS are analyzed. Five hundred thirteen patients harboring VSs underwent GKS between March 1993 and October 2009. A large VS was defined as a tumor whose diameter was > 3 cm. This paper focuses on 21 patients who harbored large VSs ranging in volume from 12.7 to 25.2 cm(3) (mean 17.3 cm(3)) and were treated by GKS. Fourteen of these patients had undergone 1 or more craniotomies previously to remove the tumor. Seven patients underwent GKS alone because of patient preference or a poor clinical condition that precluded microsurgery with general anesthesia. The mean radiation dose directed to the tumor ranged from 15 to 17.5 Gy. The mean radiation dose prescribed to the tumor margin was 11.9 Gy (range 11-14 Gy). The mean follow-up period was 66 months (range 12-155 months), and the median follow-up period was 53 months. The tumor control rate was 90.5% (19 of 21 lesions). No deterioration in facial nerve or trigeminal nerve function was noted. Disturbances in balance (some temporary) occurred in 5 patients. Three of the 21 patients developed initial tumor swelling, which required minor surgical interventions, including aspiration using an Ommaya reservoir or placement of a ventriculoperitoneal shunt. All 3 patients recovered satisfactorily after aspiration of an enlarging cyst or ventriculoperitoneal shunt placement. There was no significant correlation between tumor control and the following factors: patient age or sex, tumor volume, radiation dose, previous operation, presence of brainstem compression, petrous bone invasion, T2 signal ratio between tumor and brainstem, and presence of a cyst. However, there was a significant correlation between the T2 signal ratio between tumor and brainstem and the duration of tumor swelling (p = 0.003). Treatment of large VSs remains a challenge to neurosurgeons regardless of whether they perform microsurgery or radiosurgery. Control of tumor growth and preservation of neurological function are the main goals of treatment. Although delayed microsurgery was required in 2 patients (9.5%), the satisfactory tumor control rate and excellent preservation of facial and trigeminal nerve function are the great advantages of radiosurgery. Radiosurgery is not only a practical treatment for patients with small- to medium-sized VSs, but it is also an excellent tool for treating larger tumors up to 25 cm(3). In selected cases, radiosurgery plays an important role in treating large VSs with satisfactory results.