Assessment of Minimal Hepatic Encephalopathy with Brain MRI and EncephalApp Stroop Test

Background: Minimal hepatic encephalopathy (MHE) consists of subtle cognitive deficits that are not apparent on a standard neurological examination. Minimal hepatic encephalopathy has been reported in up to 80% of cirrhotic patients and is associated with decreased job performance, poor driving performance, impaired quality of life, and poor survival. In parallel, brain magnetic resonance imaging (MRI) abnormalities are known to occur in liver cirrhotic patients in the form of T1 globus pallidus hyperintensities. In recent years, a new psychometric test for diagnosing MHE has been developed as an app for smartphones and tablets (EncephalApp Stroop test). A translated version of the app is available in Romanian language. Aim:To use EncephalApp Stroop test for MHE diagnosis in our cirrhotic patients; to describe the main brain MRI abnormalities encountered in these patients; and to establish if Stroop test results correlate with imaging findings, clinical neurologic findings, and liver function parameters or prognosis. Material and methods:Cross-sectional study over a one-year period, involving 30 adult patients with liver cirrhosis. Subjects were evaluated through a standard neurological examination, psychometric testing using EncephalApp Stroop test, electroencephalogram and brain MRI. In parallel, 40 adult healthy controls were also recruited and evaluated with the EncephalApp Stroop test using the same methodology. Results:Age distribution was similar between the two groups (p=0.6). The mean age of patients was 50±10 years and that of controls 51±12 years. Mean Stroop result was 171±26 seconds for the patient group and 143±20 seconds for the control group (p<0.0001). There was a direct correlation between Stroop test results and age in the control group (R=0.69, p<0.0001) but not also in the patient group (R=0.28, p=0.13). Statistically significant results were obtained by using the Fischer exact test for both cut-off values: 145 seconds in patients < 45-year-old (p<0.001) and 190 seconds in those ≥45 years-old (p=0.03). MRI T1-hyperintensities of the basal ganglia, blood ammonia levels and electroencephalographic changes were not associated with poorer results. Conclusion:Our pilot study, although small, confirmed that patients with liver cirrhosis may have subtle deficits in cognitive areas like attention, concentration or reaction time. This can be assessed easily with the EncephalApp Stroop test which is readily available for use on smartphones or tablets.

Persistent repeated measurements by magnetic resonance spectroscopy demonstrate minimal hepatic encephalopathy: a case report

Minimal Hepatic Encephalopathy (MHE), previously referred to as infraclinical or subclinical is a precursor in the development of clinical hepatic encephalopathy (HE). The demonstration of MHE is done through neuropsychological testing in the absence of clinical evidence of HE, patients showing only a mild cognitive impairment. Neuropsychological tests employed consist of Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and portosystemic encephalopathy (PSE) test score. Unfortunately, there are numerous occasions when the tests prove irrelevant: in the situation of inexperienced investigators, the patient's poor education, vision problems or concurring central nervous system disease, all of which may delay or deviate from the correct diagnosis.

Magnetic resonance spectroscopy--a non-invasive method in evaluating focal and diffuse central nervous system disease

Magnetic Resonance Spectroscopy is a non-invasive method, which can be performed following a routine Magnetic Resonance investigation within the same examination, and can provide very useful molecular information related to the metabolism and function of the normal and pathological structures of the brain. Its role is increasing in the establishment of a clear diagnosis, in both focal and diffuse central nervous system diseases, and the tendency is to replace the histopathology test, in certain cases, with similar or sometimes better diagnostic accuracy. This paper summarizes the principle, method, and main clinical applications, standing as a guide to procedure performing and results interpretation.

Updates in CT characterization of thymic epithelial tumors in patients with myasthenia gravis

Thymic epithelial tumors have been traditionally classified into two main types: noninvasive and invasive thymoma. Several classifications have been proposed for thymic tumors, but according to these classifications, the prognosis of patients with thymomas varies considerably. Our purpose is to present different CT aspects according to various subtypes of thymic epithelial neoplasms based on the simplified World Health Organization classification. In this article, we will discuss and illustrate histologic and functional features of the thymus and a spectrum of thymic tumors associated with Myasthenia Gravis. Smooth contours and a round shape are the most suggestive of type A thymic epithelial tumors, whereas irregular contours and heterogeneous enhancement are the most suggestive of type C tumors. Calcifications are suggestive of type B tumors. CT findings may serve as predictors of postoperative recurrence or metastasis for the thymic epithelial tumors.

Updates in MRI characterization of the thymus in myasthenic patients

PURPOSE

To evaluate the imaging appearance of the thymus in the myasthenic patients by using chemical shift magnetic resonance imaging, and, to correlate the chemical shift ratio (CSR) with pathologic findings after surgical excision.

MATERIALS AND METHODS

In the past year, a total of 11 myasthenic patients (4 males, 7 females; age range of 26-65 years), have been investigated by MRI centered at the thymic lodge. Our protocol included a Dual-Echo technique, T1-weighted In-phase/Opposed-phase MR images in all patients. A chemical shift ratio (CSR) was calculated by comparing the signal intensity of the thymus gland with that of the chest wall muscle for quantitative analysis. For this purpose, we have used standard region-of-interest electronic cursors at a slice level of the maximum axial surface of the thymus. We have identified two patients groups: a thymic hyperplasia group and a thymic tumoral group.

RESULTS

With the decrease in the signal intensity of the thymus gland at chemical shift, the MR imaging was evident only in the hyperplasia group. The mean CSR in the hyperplasia group was considerably lower than that in the tumor group, 0,4964 ± 0,1841, compared with 1,0398 ± 0,0244. The difference in CSR between the hyperplasia and tumor groups was statistically significant (P=0,0028).

CONCLUSION

MR imaging using T1-weighted In-phase/Opposed-phase images could be a useful diagnostic tool in the preoperative assessment of the thymic lodge and may help differentiate thymic hyperplasia from tumors of the thymus gland.

The thymus in myasthenic patients: correlation between mediastinal CT imaging and histopathological findings

PURPOSE

To correlate computed tomographic (CT) appearance of the thymus with results from histologic examination of thymic tissue in myasthenic patients who underwent thymectomy.

MATERIALS AND METHODS

A retrospective study, based on case series report, between January 2000 and December 2010 on 247 patients with generalized myasthenia gravis or myasthenic syndrome explored by CT using a specific protocol, in the Radiology and Medical Imaging Department of Fundeni Clinical Institute. All subjects in the study were operated and had a histologic evaluation.

RESULTS

CT examinations of these 247 subjects showed remaining thymic mass, remnant of thymic tissue, fatty infiltration of the thymus and tumoral thymus or focal thymic mass. The results of histologic examination showed normal thymus, thymic lymphoid follicular hyperplasia, thymic atrophy, fatty infiltration and thymoma.

CONCLUSION

It was a 100% correlation between CT examinations and intra-operative findings regarding the presents of focal thymic masses in our study. In the diagnostic of focal thymic mass, the only inter-disciplinary correlation is between radiological and macroscopic aspects. CT examination has a limited value in differential diagnosis between thymic lymphoid follicular hyperplasia and thymoma.