Olfactory dysfunction in Japanese children with moderate-to-severe allergic rhinitis.

OBJECTIVE: Detailed quantitative studies on olfaction remain inadequate in patients with paediatric allergic rhinitis (AR). This study examined olfactory dysfunction in children with AR. METHODS: From July 2016 to November 2018, children aged 6-9 years were recruited and grouped as AR (n = 30) or without AR (control group, n = 10). Odour identification was evaluated by the Universal Sniff (U-Sniff) test and the Open Essence (OE). The results were compared between the AR and control groups. Intranasal mucosa findings, nasal smear eosinophil counts, blood eosinophil counts, total immunoglobulin E (IgE) levels, Japanese cedar-specific IgE and Dermatophagoides pteronyssinus-specific IgE were evaluated in all participants. Additionally, the presence of sinusitis and adenoid hypertrophy in patients with AR was also evaluated by sinus X-ray examinations. RESULTS: The median U-Sniff test scores were not significantly different between the AR and control groups (9.0 vs. 10.0, respectively; p = 0.107). The OE score was significantly lower in the AR group than in the control group (4.0 vs. 8.0; p = 0.007, respectively), especially in the moderate-to-severe AR group versus the control group (4.0 vs. 8.0; p = 0.004). Furthermore, in the OE, the correct answer rates for 'wood', 'cooking gas' and 'sweaty socks' were significantly lower in the AR group than in the control group. CONCLUSIONS: Paediatric AR patients can reduce olfactory identification ability, and the degree may be associated with the severity of AR in nasal mucosal findings. Furthermore, olfactory dysfunction may slow down the response to 'emergency situations', such as gas leak.

Enhanced structural connectivity within the motor loop in professional boxers prior to a match.

Professional boxers train to reduce their body mass before a match to refine their body movements. To test the hypothesis that the well-defined movements of boxers are represented within the motor loop (cortico-striatal circuit), we first elucidated the brain structure and functional connectivity specific to boxers and then investigated plasticity in relation to boxing matches. We recruited 21 male boxers 1 month before a match (Time1) and compared them to 22 age-, sex-, and body mass index (BMI)-matched controls. Boxers were longitudinally followed up within 1 week prior to the match (Time2) and 1 month after the match (Time3). The BMIs of boxers significantly decreased at Time2 compared with those at Time1 and Time3. Compared to controls, boxers presented significantly higher gray matter volume in the left putamen, a critical region representing motor skill training. Boxers presented significantly higher functional connectivity than controls between the left primary motor cortex (M1) and left putamen, which is an essential region for establishing well-defined movements. Boxers also showed significantly higher structural connectivity in the same region within the motor loop from Time1 to Time2 than during other periods, which may represent the refined movements of their body induced by training for the match.

MR imaging of palatine gland lesion-associated IgG4-related disease: a preliminary study.

PURPOSE: The purpose of this study was to present the novel MRI findings of palatine gland lesion-associated IgG4-related disease (PGL-IgG4-RD) and to compare the imaging features with those in normal individuals. MATERIALS AND METHODS: We retrospectively evaluated the MRI scans of 12 patients with PGL-IgG4-RD and 12 control individuals. We measured the thickness of the palatal regions and calculated the T2-weighted signal intensity ratio of palatal regions to cerebral white matter (HWR) and compared them between the PGL-IgG4-RD and control groups. RESULTS: In univariate analysis, the HWR of the palatal regions on T2-weighted imaging was smaller in the PGL-IgG4-RD group than in the control group (average = 1.2 vs. 1.9, p < 0.001). The palate thickness in patients with PGL-IgG4-RD was significantly greater than that in controls (average = 12 vs 6 mm, p < 0.001). The cut-off value of the between-group palate thickness on coronal MRI was 8 mm. CONCLUSION: The thickening of the palatal regions seen with low signal intensity on T2-weighted imaging may be a characteristic imaging feature of PGL-IgG4-RD. Such findings will be useful for the timely diagnosis and subsequent treatment planning of IgG4-RDHP.

Multifaceted structural magnetic resonance imaging findings in demented patients with pathologically confirmed TDP-43 proteinopathy.

This short report clarifies the heterogeneity of structural magnetic resonance imaging (MRI) findings in seven demented patients due to pathologically accumulated TAR DNA-binding protein-43 (TDP-43) protein using visual analyses including visual rating scales (i.e., global cortical atrophy and medial temporal atrophy scales). In addition to the well-known frontotemporal lobar atrophy, structural MRI has revealed multifaceted imaging findings including asymmetric atrophy of the frontoparietal lobe and cerebral peduncle, midbrain atrophy, and localized or diffuse white matter T2 hyperintensity. Understanding of these multifaceted neuroimaging findings is important for the precise antemortem diagnosis of TDP-43 proteinopathy.

Extensive perivascular dissemination of cerebral miliary tuberculomas: a case report and review of the literature.

Cerebral tuberculosis (TB) presents most frequently as meningitis in the basilar cistern; however, it can also manifest in various other ways, such as localized encephalitis, abscess, and tuberculoma. Here, focusing on imaging findings, we report an immunocompetent case who demonstrated multiple parenchymal lesions and was diagnosed with cerebral TB after testing positive on QuantiFERON (QTF); her clinical signs/symptoms and laboratory findings responded well to anti-TB medication therapy. The patient was a 60-year-old woman with the chief complaints of headache and consciousness disturbance. On admission, cerebrospinal fluid (CSF) examination showed increased monocyte predominance. T2-weighted images showed multiple, widely distributed hyperintense lesions in the periventricular and deep white matter. Gadolinium-enhanced three-dimensional gradient echo T1-weighed images revealed numerous granules or faint, small, enhanced foci in lesions in the periventricular and deep white matter, central gray matter, and hippocampus. Some abnormal sulcal enhancement was detected in the pia mater, indicating meningitis. Clinically, the diagnosis was difficult to make, but as the QTF result was positive, anti-TB drugs were administered, after which both the symptoms and CSF cell count showed improvement.

[Imaging-Based Diagnosis of Craniocervical Artery Dissections: A Strategy Focusing on the Pathological Condition and MRI Technique].

Magnetic resonance imaging (MRI) is a non-invasive and useful imaging modality with a high contrast resolution to diagnose craniocervical artery dissections. However, to avoid misinterpretations and misdiagnosis, it is mandatory to understand not only the pathological condition of craniocervical artery dissection, but also the principles of MRI techniques. In this manuscript, the details of MRI findings, especially when using high-resolution vessel wall imaging, are discussed.

Influence of Gd-EOB-DTPA on T1 dependence of the proton density fat fraction using magnetic resonance spectroscopy.

This phantom study assessed the effect of Gd-EOB-DTPA on T1 bias (difference in T1 between water and fat) of the proton density fat fraction when using magnetic resonance spectroscopy. Phantoms containing varying fat percentages, without and with Gd-EOB-DTPA (precontrast and postcontrast, respectively), were scanned with repetition times ranging from 1000 to 5000 ms. The relationship between the proton density fat fraction at a reference repetition time of 5000 ms and that using different repetition times, was evaluated in the precontrast and postcontrast phantoms using linear regression and Bland-Altman analyses. In the precontrast phantom, as the repetition time increased, the slope tended to approach one. In the postcontrast phantom, the slope and intercept were near one and zero, respectively. The mean difference was smaller in the postcontrast phantom (range - 0.24 to - 0.01%) than in the precontrast phantom (range 0.12 to 3.52%). We conclude that I1 bias is minimized by Gd-EOB-DTPA.

Correction to: Influence of Gd-EOB-DTPA on proton density fat fraction using the six-echo Dixon method in 3 Tesla magnetic resonance imaging.

A diameter of glass bottles in phantoms in the above article (2 cm) was incorrect. The correct diameter is 4.5 cm.

Multicenter, multivendor phantom study to validate proton density fat fraction and T2* values calculated using vendor-provided 6-point DIXON methods.

PURPOSE: To evaluate the reproducibility of proton density fat fraction (PDFF) and T2* in a fat-water phantom on three different 3 T MRI systems using 6-point DIXON methods. METHODS: A phantom which included varying fat volume percentages (true fat fraction [FF]) was scanned by three 3 T MR machines, and PDFF and T2* were measured. RESULTS: The mean difference between true FF and PDFF was small in all vendors (-2.11% to 0.41%). However, the difference ratio for T2* values was large among vendors (1.79 to 3.36). CONCLUSIONS: True FF and PDFF were consistent across vendors; however, T2* varied greatly.

Influence of Gd-EOB-DTPA on proton density fat fraction using the six-echo Dixon method in 3 Tesla magnetic resonance imaging.

The purpose of this study was to evaluate whether disodium gadoxetate (Gd-EOB-DTPA) affects proton density fat fractions (PDFFs) during use of the multiecho Dixon (meDixon) method in phantom and simulation magnetic resonance imaging (MRI) studies at 3 T. Fat-water phantoms comprising vegetable fat-water emulsions with varying fat volume percentages (0, 5, 10, 15, 20, 30, 40, and 50) and Gd-EOB-DTPA concentrations (0 and 0.4 mM) were prepared. Phantoms without Gd-EOB-DTPA were defined as precontrast, and those with Gd-EOB-DTPA were defined as postcontrast. All phantoms were scanned with a 3 T MRI system using the meDixon method, and precontrast and postcontrast PDFFs were calculated. Simulated pre and postcontrast PDFFs in the liver were calculated using a theoretical formula. The relationship between PDFFs measured in the pre and postcontrast phantoms was evaluated using linear regression and Bland-Altman analysis. The regression analysis comparing the pre and postcontrast PDFFs yielded a slope of 0.77 (P < 0.001). The PDFFs on the postcontrast phantom were smaller than those on the precontrast phantom. The mean difference between the PDFFs on the pre and postcontrast phantoms was 6.12% (95% confidence interval 3.13 to 9.10%; limits of agreement -0.88 to 13.11%). The simulated PDFF on the postcontrast phantom was smaller than that on the precontrast phantom. We demonstrated that the PDFF measured using the meDixon was smaller on postcontrast than on precontrast at 3 T, if a low flip angle was used. This tendency was also seen in the simulation study results.

Distribution and chemical forms of gadolinium in the brain: a review.

In the 3 years since residual gadolinium-based contrast agent (GBCA) in the brain was first reported, much has been learned about its accumulation, including the pathway of GBCA entry into the brain, the brain distribution of GBCA and its excretion. Here we review recent progress in understanding the routes of gadolinium deposition in brain structures.

Gadolinium deposition in the brain.

Gadolinium is highly toxic. Gadolinium-based contrast agents (GBCAs) consist of gadolinium ions and a chelating agent that binds the gadolinium ion tightly in order not to manifest its toxicity. Knowledge regarding gadolinium deposition in patients with normal renal function has advanced dramatically. Since 2014, increasing attention has been given to residual gadolinium known to accumulate in the tissues of patients with normal renal function. High signal intensity on T1-weighted images (T1WI) in the dentate nucleus, globus pallidus, and pulvinar region of the thalamus correlate roughly with the number of previous GBCA administrations. Pathological analyses have revealed that residual gadolinium is deposited not only in these brain regions, but also in extracranial tissues such as liver, skin and bone. The risks attendant with these deposits are unknown. Common sense dictates that gadolinium deposition be kept as low as possible, and that gadolinium contrast agents be used only when absolutely necessary, with preferential use of macrocyclic chelates, which seem to be deposited at lower concentrations.

Contribution of metals to brain MR signal intensity: review articles.

Various metals are essential nutrients in humans, and metal shortages lead to a variety of deficiency diseases. Metal concentration abnormalities may cause metal deposition in the brain, and magnetic resonance imaging (MRI) is the most potent and sensitive technique now available for detecting metal deposition given the difficulties associated with performing brain tissue biopsy. However, the brain contains many kinds of metals that affect the signal intensity of MRI, which has led to numerous misunderstandings in the history of metal analysis. We reviewed the history of brain metal analysis with histologic findings. Typically, manganese overload causes high signal intensity on T1-weighted images (T1WI) in the globus pallidus, iron overload causes low signal intensity in the globus pallidus on T2-weighted images, and gadolinium deposition causes high signal intensity in the dentate nucleus, globus pallidus, and pulvinar of thalamus on T1WI. However, because nonparamagnetic materials and other coexisting metals also affect the signal intensity of brain MRI, the quantitative analysis of metal concentrations is difficult. Thus, when analyzing metal deposition using MRI, caution should be exercised when interpreting the validity and reliability of the obtained data.

Brain gadolinium deposition after administration of gadolinium-based contrast agents.

Gadolinium-based contrast agents (GBCAs) consist of gadolinium ions and a chelating agent that binds the gadolinium ion tightly so that its toxicity is not manifested. However, in 2013, an association between brain MRI abnormalities and a history of GBCA administration was first reported. Even in patients with normal renal function, increased signal intensity in the dentate nucleus and globus pallidus on unenhanced T1-weighted images showed a positive correlation with previous exposure to linear chelate type GBCAs, but not to macrocyclic chelate type ones. This difference of GBCAs is speculated to reflect the stability of GBCAs, and de-chelated gadolinium deposition has been strongly suspected. Using inductively coupled plasma mass spectroscopy, gadolinium was detected from patients' brains with a history of repeated GBCA administration. In some cases, the gadolinium concentration of a patient's brain with normal renal function exceeded the gadolinium concentration of the skin in nephrogenic systemic fibrosis patients, but without any histological change. The actual risk has not been documented yet, but it seems important to consider the potential unknown risks of residual gadolinium in our decisions regarding GBCA administration, and to make efforts to minimize any residual gadolinium in the patient's body.

Gadolinium-based Contrast Agent Accumulates in the Brain Even in Subjects without Severe Renal Dysfunction: Evaluation of Autopsy Brain Specimens with Inductively Coupled Plasma Mass Spectroscopy.

PURPOSE: To use inductively coupled plasma mass spectroscopy (ICP-MS) to evaluate gadolinium accumulation in brain tissues, including the dentate nucleus (DN) and globus pallidus (GP), in subjects who received a gadolinium-based contrast agent (GBCA). MATERIALS AND METHODS: Institutional review board approval was obtained for this study. Written informed consent for postmortem investigation was obtained either from the subject prior to his or her death or afterward from the subject's relatives. Brain tissues obtained at autopsy in five subjects who received a linear GBCA (GBCA group) and five subjects with no history of GBCA administration (non-GBCA group) were examined with ICP-MS. Formalin-fixed DN tissue, the inner segment of the GP, cerebellar white matter, the frontal lobe cortex, and frontal lobe white matter were obtained, and their gadolinium concentrations were measured. None of the subjects had received a diagnosis of severely compromised renal function (estimated glomerular filtration rate <45 mL/min/1.73 m(2)) or acute renal failure. Fisher permutation test was used to compare gadolinium concentrations between the two groups and among brain regions. RESULTS: Gadolinium was detected in all specimens in the GBCA agent group (mean, 0.25 µg per gram of brain tissue ± 0.44 [standard deviation]), with significantly higher concentrations in each region (P = .004 vs the non-GBCA group for all regions). In the GBCA group, the DN and GP showed significantly higher gadolinium concentrations (mean, 0.44 µg/g ± 0.63) than other regions (0.12 µg/g ± 0.16) (P = .029). CONCLUSION: Even in subjects without severe renal dysfunction, GBCA administration causes gadolinium accumulation in the brain, especially in the DN and GP.

The incidence of double hypoglossal canal in Japanese: evaluation with multislice computed tomography.

BACKGROUND AND PURPOSE: Double hypoglossal canal, namely a hypoglossal canal bridging, is a normal variation of the hypoglossal canal. Racial differences in the prevalence of double hypoglossal canal have been reported. We evaluated the prevalence of double hypoglossal canal in a Japanese population with multidetector computed tomography (MDCT). MATERIALS AND METHODS: We reviewed five hundred and ninety consecutive patients (mean age, 61 years: range, 15-94 years: 254 men, 336 women) who underwent computed tomographic angiography (CTA) of the brain for a variety of CNS abnormalities. Two radiologists achieved consensus on the canal being single or double, and measured the sizes of single canals on CT images. Kappa statistics was used to test the reliability between the 2 investigators. A logistic regression was used to evaluate the prevalence of double hypoglossal canal and the following factors: sex, age, and laterality. Student's t-test was used to evaluate the asymmetry of single hypoglossal canal diameters. Statistical significance was accepted at P < 0.05. RESULTS: Double hypoglossal canal was identified in 16.9% of the patients, and was bilateral in 2.2%. Double hypoglossal canal was significantly more frequent on the left side than right (P = 0.004, odds ratio = 1.79) and in males than females (P = 0.011, odds ratio = 1.67). A larger left or right-sided canal was found in 31.6% and 12.2% of the patients, respectively, following the same side preference as that of double hypoglossal canal. Almost perfect agreement was achieved between the two readers (k = 0.975). CONCLUSIONS: In this Japanese population, the prevalence of a double hypoglossal canal was 16.9%, of which 2.2% were bilateral. Double hypoglossal canal was more frequent in males than females, and on the left side than right.

High Signal Intensity in Dentate Nucleus on Unenhanced T1-weighted MR Images: Association with Linear versus Macrocyclic Gadolinium Chelate Administration.

PURPOSE: To assess whether an association exists between hyperintensity in the dentate nucleus (DN) on unenhanced T1-weighted magnetic resonance (MR) images and previous administration of gadolinium-based contrast agents (GBCAs) that contain different types of gadolinium chelates. MATERIALS AND METHODS: The institutional review board approved this study. Written informed consent was waived because this was a retrospective study. Evaluated were 127 cases among 360 consecutive patients who underwent contrast agent-enhanced brain MR imaging. Two radiologists conducted visual evaluation and quantitative analysis on unenhanced T1-weighted MR images by using regions of interest. DN-to-cerebellum (DN/cerebellum) signal intensity ratios were calculated and the relationship between DN/cerebellum and several factors was evaluated, including the number of previous linear chelate and/or macrocyclic GBCA administrations by using a generalized additive model. The Akaike information criterion was used in model selection. Interobserver correlation was evaluated with paired t tests and the Lin concordance correlation coefficient. RESULTS: The images of nine patients (7.1%) showed hyperintensity in the DN. Twenty-three patients (18.1%) received linear GBCAs (median, two patients; maximum, 11 patients), 36 patients (28.3%) received macrocyclic GBCAs (median, two patients; maximum, 15 patients), 14 patients (11.0%) received both types of GBCA (linear [median, two patients; maximum, five patients] and macrocyclic [median, three patients; maximum, eight patients]), and 54 patients (42.5%) had no history of administration of gadolinium chelate. Interobserver correlation was almost perfect (0.992 [95% confidence interval: 0.990, 0.994]). The DN/cerebellum ratio was associated with linear GBCA (P < .001), but not with macrocyclic GBCA exposure (P = .875). According to the Akaike information criterion, only linear GBCA was selected for the final model, and the DN/cerebellum ratio had strong association only with linear GBCA. CONCLUSION: Hyperintensity in the DN on unenhanced T1-weighted MR images is associated with previous administration of linear GBCA, while the previous administration of macrocyclic GBCAs showed no such association.