Immune-related aseptic meningitis diagnosed by Cube FLAIR on enhanced magnetic resonance imaging for a lung cancer patient administered atezolizumab: A case report

Immune checkpoint inhibitors (ICIs) can cause immune-related adverse events (irAEs), such as neurological toxicity. A 46-year-old man was diagnosed with squamous cell lung cancer. Lung cancer recurred 3 years after he experienced left segmental lung rejection. Therefore, he received atezolizumab as fourth-line chemotherapy. He experienced fever, headache, and decreased consciousness 10 days after the first dose of atezolizumab. Plain head computed tomography and cerebrospinal fluid examination showed no significant findings. Magnetic resonance imaging (MRI) with a Gadolinium (Gd)-enhanced Cube fluid-attenuated inversion recovery (FLAIR) sequence showed nodular abnormalities with contrast enhancement. Thus, aseptic meningitis caused by ICIs was suspected. His consciousness level gradually improved with glucocorticoid therapy. Moreover, most nodular abnormalities observed on cerebral MRI disappeared concurrently. Thus, Gd-enhanced Cube FLAIR sequence has the unique ability to reveal immune-related aseptic meningiti

Immune‐related aseptic meningitis diagnosed by Cube FLAIR on enhanced magnetic resonance imaging for a lung cancer patient administered atezolizumab: A case report

Abstract Immune checkpoint inhibitors (ICIs) can cause immune‐related adverse events (irAEs), such as neurological toxicity. A 46‐year‐old man was diagnosed with squamous cell lung cancer. Lung cancer recurred 3 years after he experienced left segmental lung rejection. Therefore, he received atezolizumab as fourth‐line chemotherapy. He experienced fever, headache, and decreased consciousness 10 days after the first dose of atezolizumab. Plain head computed tomography and cerebrospinal fluid examination showed no significant findings. Magnetic resonance imaging (MRI) with a Gadolinium (Gd)‐enhanced Cube fluid‐attenuated inversion recovery (FLAIR) sequence showed nodular abnormalities with contrast enhancement. Thus, aseptic meningitis caused by ICIs was suspected. His consciousness level gradually improved with glucocorticoid therapy. Moreover, most nodular abnormalities observed on cerebral MRI disappeared concurrently. Thus, Gd‐enhanced Cube FLAIR sequence has the unique ability to reveal immune‐related aseptic meningiti

Dynamic changes in apparent diffusion coefficient of white matter and ventricular system during cardiac cycle in idiopathic normal pressure hydrocephalus

The purpose of our study was to compare temporal changes in the apparent diffusion coefficient （ADC） of the brain parenchyma and ventricular system independent of water restriction over the cardiac cycle among 14 patients with idiopathic normal‐pressure hydrocephalus （iNPH）, 9 patients with atrophic ventricular dilation （VD）, and 8 healthy control subjects. On a 1.5‐T magnetic resonance imaging system, electrocardiogram‐triggered single‐shot diffusion echo planar imaging was performed with sensitivity encoding and half‐scan techniques to minimize the bulk motion. Then, an ADC image of each cardiac phase was calculated. The normalized‐ΔADC image was calculated by using the following equation from all cardiac‐phase ADC images （20 phases） :Normalized‐ΔADC＝（ADCmax－ADCmin）/ADCmin, where ADCmax and ADCmin represent the maximum and minimum ADC during the cardiac cycle, respectively. We assessed the mean normalized‐ΔADC, maximum change in ADC（ΔADC）, and mean ADC of the cardiac phases at which the ADC change was stable （ADCstable） in the frontal white matter and the three ventricular regions. No significant differences were observed in the normalized‐ΔADCs of healthy subjects among the brain regions, whereas significant differences were observed in ΔADC and ADCstable between the frontal white matter and each ventricular region. The mean normalized‐ΔADCs of the third ventricle and frontal white matter were significantly higher in the iNPH group than in the control and atrophic VD groups. Normalized‐ΔADC analysis in the frontal white matter and third ventricle may provide more detailed information on intracranial conditions in iNPH, which may be useful for determining a diagnosis

Usefulness of intravoxel incoherent motion MRI for visualizing slow cerebrospinal fluid motion

Background:In the cerebrospinal fluid (CSF) dynamics, the pulsations of cerebral arteries and brain is considered the main driving force for the reciprocating bidirectional CSF movements. However, measuring these complex CSF movements on conventional flow-related MRI methods is difficult. We tried to visualize and quantify the CSF motion by using intravoxel incoherent motion (IVIM) MRI with low multi-b diffusion-weighted imaging.Methods:Diffusion-weighted sequence with six b values (0, 50, 100, 250, 500, and 1000 s/mm2) was performed on 132 healthy volunteers aged ≥ 20 years and 36 patients with idiopathic normal pressure hydrocephalus (iNPH). The healthy volunteers were divided into three age groups (< 40, 40 to < 60, and ≥ 60 years). In the IVIM analysis, the bi-exponential IVIM fitting method using the Levenberg-Marquardt algorithm was adapted. The average, maximum, and minimum values of ADC, D, D*, and fraction of incoherent perfusion (f) calculated by IVIM were quantitatively measured in 45 regions of interests in the whole ventricles and subarachnoid spaces.Results:Compared with healthy controls aged ≥ 60 years, the iNPH group had significantly lower mean f values in all the parts of the lateral and 3rd ventricles, whereas significantly higher mean f value in the bilateral foramina of Luschka. In the bilateral Sylvian fossa, which contain the middle cerebral bifurcation, the mean f values increased gradually with increasing age, whereas those were significantly lower in the iNPH group. In the 45 regions of interests, the f values in the bilateral foramina of Luschka were the most positively correlated with the ventricular size and indices specific to iNPH, whereas that in the anterior part of the 3rd ventricle was the most negatively correlated with the ventricular size and indices specific to iNPH. Other parameters of ADC, D, and D* were not significantly different between the two groups in any locations.Conclusions:The f value on IVIM MRI is useful for evaluating small pulsatile complex motion of CSF throughout the intracranial CSF spaces. Patients with iNPH had significantly lower mean f values in the whole lateral ventricles and 3rd ventricles and significantly higher mean f value in the bilateral foramina of Luschka, compared with healthy controls aged ≥ 60 years