Case report: A case of posterior reversible encephalopathy in postpartum preeclampsia.

RATIONALE: Posterior reversible encephalopathy syndrome is a neurological condition characterized by headache, convulsions, altered consciousness, and visual disturbance with specific radiological features, which is characterized by contrast enhancement in the occipital lobe on T2-weighted image. We report a case of sudden visual impairment of both eyes 6 days after childbirth diagnosed as postpartum preeclampsia and posterior reversible encephalopathy syndrome (PRES) through radiological examination. PATIENT CONCERNS: A 31-year-old female patient with headache and visual disturbance visited the clinic. DIAGNOSIS: Visual acuity was light perception in the right eye and hand motion in the left eye; pupillary light reflections of both eyes were normal. In the field of view test, the waveform was not observed in the defect pattern visual field power test, and the amplitude was greatly reduced in the visual field test. 1+ proteinuria was observed on urine test and magnetic resonance imaging showed contrast enhancement under both parietal and occipital cortex. INTERVENTIONS: Hospitalization was done for blood pressure control and examination of related disease under suspicion of PRES caused by postpartum preeclampsia. OUTCOMES: Four weeks after diagnosis, vision and visual field defects recovered to normal, and the previously observed lesion on magnetic resonance imaging completely improved 3 months after the initial visit, and it was diagnosed as PRES. LESSONS: PRES in postpartum preeclampsia can cause rapid vision and symptoms, visual field loss, and accurate follow-up diagnosis with relevant imaging and clinical patterns can improve vision.

Evaluation of the robustness of the preprocessing technique improving reversible compressibility of CT images: tested on various CT examinations.

PURPOSE: To modify the preprocessing technique, which was previously proposed, improving compressibility of computed tomography (CT) images to cover the diversity of three dimensional configurations of different body parts and to evaluate the robustness of the technique in terms of segmentation correctness and increase in reversible compression ratio (CR) for various CT examinations. METHODS: This study had institutional review board approval with waiver of informed patient consent. A preprocessing technique was previously proposed to improve the compressibility of CT images by replacing pixel values outside the body region with a constant value resulting in maximizing data redundancy. Since the technique was developed aiming at only chest CT images, the authors modified the segmentation method to cover the diversity of three dimensional configurations of different body parts. The modified version was evaluated as follows. In randomly selected 368 CT examinations (352,787 images), each image was preprocessed by using the modified preprocessing technique. Radiologists visually confirmed whether the segmented region covers the body region or not. The images with and without the preprocessing were reversibly compressed using Joint Photographic Experts Group (JPEG), JPEG2000 two-dimensional (2D), and JPEG2000 three-dimensional (3D) compressions. The percentage increase in CR per examination (CRI) was measured. RESULTS: The rate of correct segmentation was 100.0% (95% CI: 99.9%, 100.0%) for all the examinations. The median of CRI were 26.1% (95% CI: 24.9%, 27.1%), 40.2% (38.5%, 41.1%), and 34.5% (32.7%, 36.2%) in JPEG, JPEG2000 2D, and JPEG2000 3D, respectively. CONCLUSIONS: In various CT examinations, the modified preprocessing technique can increase in the CR by 25% or more without concerning about degradation of diagnostic information.

JPEG2000 compression of CT images used for measuring coronary artery calcification score: assessment of optimal compression threshold.

OBJECTIVE: The purpose of our study was to assess the acceptable compression threshold for JPEG2000 compression of CT images used for measuring coronary artery calcification scores (CACS) in terms of variability. MATERIALS AND METHODS: In a retrospective review, 80 patients who had undergone CT for determination of the CACS were compiled in four subsets (20 scans each) according to CACS: 0, subset A; > 0 to ≥ 100, subset B; > 100 to ≤ 400, subset C; and > 400, subset D. Each scan was compressed using eight compression ratios (CRs). We measured the CACS on all 720 CT scans (80 original and 640 compressed scans). For each compressed scan, the variability in CACS was evaluated by comparing with the CACS of the corresponding original CT scan. RESULTS: For each subset and each CR, we determined whether the upper limit of the one-sided 95% CI of the variability in CACS exceeded 5%. The variability in CACS tended to increase as the CR increased and tended to decrease in the order of increasing CACSs at each CR (i.e., subset B > subset C > subset D). With 5% as the limit of variability, acceptable compression CRs were between 20:1 and 25:1 for subset B; between 40:1 and 60:1 for subset C; and > 100:1 for subset D. CONCLUSION: A level of 20:1 could be a potentially acceptable threshold for JPEG2000 compression of CT images used for measuring CACS, with 5% of the variability in CACS as the acceptable limit of variability.

Fluorescence turn-on probe for homocysteine and cysteine in water.

A simple fluorescent probe based on an ortho-hydroxy aldehyde-functionalized coumarin showed selective responses to homocysteine and cysteine by fluorescence turn-on.