Magnetic resonance imaging changes and clinical features of reversible posterior leukoencephalopathy syndrome

Abstract

Objectives: Reversible posterior leukoencephalopathy syndrome (RPLS) is a rare clinical imaging syndrome. The causes of RPLS are complex and diverse, the pathogenesis is not yet clear. The onset is urgent and the onset age span is large, ranging from children to the elderly. The clinical symptoms of RPLS have no significant specificity, which can be manifested as headache, blurred vision, disturbance of consciousness or seizures. Clinicians have little knowledge on the disease, which may lead to misdiagnosis or missed diagnosis. This study aims to analyze and summarize the MRI changes and clinical characteristics regarding RPLS patients, so as to provide basis for rapid diagnosis and timely intervention for this disease.

Methods: The clinical data and complete imaging data of 77 patients with RPLS diagnosed in Xiangya Hospital of Central South University from January 2012 to March 2021 were retrospectively collected. The main image data include T1 weighted imaging (T1WI), T2 weighted imaging (T2WI), T2 liquid attenuation inversion recovery (T2-FLAIR), diffusion weighted imaging (DWI) (b value=1 000×10-6 mm2/s), and apparent diffusion coefficient (ADC). The case group included 63 patients who underwent DWI examination, and 71 normal controls matched in age and sex. The characteristics of patients' magnetic resonance signals and the ADC value of 19 regions of interest (ROI) were analyzed. The differences in bilateral ADC value in the case group, the difference of ADC value between the case group and the normal control group, and the difference of ADC value in the case group before and after treatment were compared.

Results: Compared with the normal control group, the ADC value of the right frontal lobe, bilateral parietal lobe, bilateral thalamus, bilateral head of caudate nucleus, left lenticular nucleus, right internal capsule, bilateral temporal lobe and pons in the case group were significantly higher (all P<0.01). There was no significant difference in ADC value of bilateral sides of the case group and before and after treatment in the case group (all P>0.01). The lesions of RPLS were widely distributed and multiple, usually high signal in the posterior parieto temporo occipital lobe or pons of the brain, and involved the cortex and subcortical white matter. Most of them were bilateral, but not completely symmetrical.

Conclusions: The imaging manifestations of RPLS and the occurrence and development of clinical symptoms are basically synchronous. The imaging manifestations are specific. Magnetic resonance imaging can show the range of involvement of RPLS. ADC value can provide information on the severity of the disease and predict the prognosis. There are few reversible diseases. It is very important to fully understand and timely diagnose the disease.

Keywords: apparent diffusion coefficient; magnetic resonance; reversible posterior leukoencephalopathy syndrome.

图1

ADC图上19个ROI选取的位置及面积 Figure 1 Selected positions and areas of the 19 ROIs on the ADC map A: Two ROI locations are namely frontal lobe and parietal lobe, and the area of frontal lobe checked is 360 mm² and parietal lobe is 320 mm². B: Three ROI locations are namely caudate head, thalamus and occipital lobe, and the area of caudate head checked is 50 mm², thalamus is 120 mm², and occipital lobe is 320 mm². C: Three ROI locations are namely lenticular nucleus, internal capsule and posterior temporal lobe, and the area of lenticular nucleus checked is 150 mm² , internal capsule is 40 mm² and posterior temporal lobe is 320 mm². D: Two ROI locations are namely cerebellum and pons, and the area of cerebellum checked is 380 mm² and pons is 240 mm².

图2

1例3岁地中海贫血女性患儿治疗前后RPLS病变的影像学变化 Figure 2 Images changes of RPLS lesions in a 3-year-old female patient with thalassemia before and after treatment A-E: Images of the patient before treatment, including T₁WI, T₂WI, T₂-FLAIR, DWI and ADC value image. Bilateral parietal temporal lobe swelling, shallow sulcus fission, long T₁ and long T₂ signal, high signal on T₂-FLAIR, iso-slightly high signal on DWI, high ADC value, and no obvious enhancement after enhancement. F-K: Re-examination after treatment, the lesions absorbed and disappeared.

图3

1例28岁高血压男性患者治疗前后RPLS病变的影像学变化 Figure 3 Imaging changes of RPLS lesions in a 28-year-old male patient hypertension before and after treatment A-E: Lesion is located in the pons with long T₁ and long T₂ signal; T₂-FLAIR is hyperintense; DWI is iso-slightly hyperintense, and ADC is high. F-J: Review after treatment, lesions are basically absorbed.

图4

1例23岁慢性肾功能不全男性患者RPLS病变的影像学表现 Figure 4 Imaging findings of RPLS in a 23-year-old male patient with chronic renal insufficiency A-E: Images of the patient before treatment, including T₁WI, T₂WI, T₂-FLAIR, DWI and ADC value image. Multiple patchy abnormal signals can be seen in bilateral temporal lobes and occipital lobes, showing long T₁ and long T₂ signals. T₂-FLAIR is high signal, DWI is slightly lower signal, and ADC is high value. F: After enhancement, the lesion has no obvious enhancement.