Tachycardia alert from an implantable loop recorder after brain magnetic resonance imaging—The importance of patient history

Short stature is a common concern that necessitates pediatric endocrinology evaluation. Growth hormone (GH) deficiency is often included as an etiology. Brain and pituitary Magnetic Resonance Imaging (MRI) with gadolinium-based contrast agents (GBCAs) is the imaging modality of choice in assessing patients with GH deficiency. Given the significant strides made in MRI technology that allow improved spatial and contrast resolution, the necessity of using contrast material when obtaining brain and pituitary MRI in cases of short stature and isolated GH deficiency should be reassessed. We preformed a retrospective review of otherwise healthy patients with short stature and/or GH deficiency who underwent brain and pituitary MRI without and with contrast, to assess the benefit of contrast administration. Introduction: Short stature is a common concern that necessitates pediatric endocrinology evaluation. The etiologies of short stature are diverse. GH deficiency is often included as an etiology although it accounts for only 1-2% of short stature cases. The prevalence of GH deficiency is reported to be ~ 1:3500. The vast majority of GH deficiency cases are idiopathic in nature with only 20% due to organic causes. The organic causes of GH deficiency include congenital central nervous system (CNS) anomalies, tumors and other pathologic conditions that involve the pituitary-hypothalamic region. As a result, the radiological assessment of the hypothalamic-pituitary region is considered standard of care for evaluating patients with GH deficiency. Although brain and pituitary MRI is the imaging modality of choice in assessing patients with GH deficiency, its yield in cases of isolated GH deficiency is very low. In a study of 40 otherwise normal patients with isolated GH deficiency, 35 (87.5%) had normal brain MRIs. The abnormal findings of brain MRI in the minority of isolated GH deficiency cases included pituitary hypoplasia, pituitary stalk agenesis, lack of the normal T1-weighted pituitary hyperintensity in the posterior part of the sella turcica, and the presence of a high-intensity signal at the infundibular level representing ectopic neurohypophysis. Traditionally, these brain and pituitary MRI images are obtained with the use of contrast material (gadolinium). The main purpose of using contrast material is for the evaluation of pituitary microadenomas. Given the fact that significant strides made in MRI technology and pituitary microadenomas are not appeared to be associated with GH deficiency, the necessity of using contrast material when obtaining brain and pituitary MRI in cases of short stature and isolated GH deficiency should be reassessed. GBCAs have been shown to deposit in different tissues including the kidneys and the brain. The risk increases with repeated doses. The clinical significance of this deposition is unclear at this time but warrants caution especially in pediatric population who have a longer expected lifespan to manifest any delayed effects. Allergic reactions and gastrointestinal symptoms in pediatric patients can occur with GBCA administration, although the incidence is low. Using contrast material also increases the total cost of the MRI study and prolongs the time needed to complete it. Moreover, in order to use contrast material, intravenous venous (IV) access is required which causes discomfort and additional stress to children and their families. Therefore, we performed a retrospective review of otherwise healthy patients with short stature and/or growth hormone deficiency who underwent brain and pituitary MRI without and with contrast, to assess whether contrast administration led to diagnoses that would have otherwise been missed and/or impacted the patient’s clinical course.Objectives: - To compare the diagnostic yield of non-contrast MRI with pre and post-contrast MRI of the brain and pituitary in evaluation of pediatric patients with short stature and/or growth hormone deficiency.- A secondary objective is to measure the size of the pituitary gland and correlates it with peak growth hormone levels (using insulin/argenine). Methodology: We included patients who underwent brain/pituitary MRI with/without contrast performed at our institution between Jan 2013-Dec 2018 who have short stature/GH deficiency. We excluded patients with known diagnosis of other pituitary hormone deficiencies prior to obtaining MRI studies, genetic and neurological disorders, known tumors/malignancies of any type, or renal failure. Two pediatric neuroradiologists independently reviewed the brain and pituitary MRI of these patients (each read 50% of the cohort) blinded to the clinical data and diagnoses. Each radiologist initially reviewed only the non-contrast portions of the studies, and subsequently, the same radiologist reviewed the entire study, including pre- and post-contrast portions in a separate session. The two sessions were 6 weeks apart to avoid recall bias. Several imaging findings including size and morphology of pituitary gland, presence of congenital anomalies or focal lesions and any associated intracranial findings systematically recorded, and subsequently analyzed. Hypotheses: 1.The incidence of finding congenital pituitary cysts is the same when obtaining brain/pituitary MRI imaging using gadolinium contrast versus when not using contrast in patients with short stature and or isolate GH deficiency. 2.The incidence of discovering abnormal infundibulum is the same when obtaining brain/pituitary MRI imaging using gadolinium contrast versus when not using contrast in patients with short stature and or isolate GH deficiency. 3.Small pituitary size correlate with GH deficiency. Results: -We identified 327 patients with short stature/GH deficiency from Jan 2013-Dec 2018-224 (68.5%) are males and 103 (31.5%) are females. -The mean age at the time of imaging is 10 years and the median is 11 years. -161 (49.24%) have height z-score < -2.25 and 166 (50.76%) have height z-score > -2.25.-82 (25.07%) have IGF1 z-score for age < -2, 102 (31.19%) have z-score ≥-2 to ≤ -1, 141 (43.12%) have z-score > -1 and 2 (0.62%) have no level done.-63 (19.27%) have GH peak <5, 87 (26.61%) have GH peak 5-7.99, 53 (16.21%) have GH peak 8-9.99, 30 (9.17%) have GH peak > 10 and 94 (28.75%) did not undergo GH provocative testing. -The kappa coefficient for pars intermedia cyst on pre vs. post contrast imaging is 0.74 and 0.55 for the infundibulum on pre vs. post contrast imaging. -The mean pituitary height for patients with IGF z-score < -2 is 3.9 mm, 4 mm for z-score ≥- 2 to ≤ -1 and 4.3 mm for z-score > -1-The mean pituitary height for patients with peak GH < 5 is 3.8 mm, 4.2 mm for peak 5-7.99, 4.3 mm for peak 8-9.99 and 4.4 mm for peak > 10. Conclusion: This question has not been answered or even raised in the literature. Our findings suggest that the there is no added benefit to use gadolinium when obtaining brain/pituitary MRI for the evaluation of GH deficiency/short stature. Furthermore, it seems that there is an association between the pituitary height and the GH status of the cohort which is in line with previous published studies.

Automated tissue segmentation of brain magnetic resonance (MR) images has attracted extensive research attention. Many segmentation algorithms have been proposed for this issue. However, due to the existence of noise and intensity inhomogeneity in brain MR images, the accuracy of the segmentation results is usually unsatisfactory. In this paper, a high-accuracy brain MR image segmentation algorithm based on the information bottleneck (IB) method is presented. In this approach, the MR image is first mapped into a “local-feature space”, then the IB method segments the brain MR image through an information theoretic formulation in this local-feature space. It automatically segments the image into several clusters of voxels, by taking the intensity information and spatial information of voxels into account. Then, after the IB-based clustering, each cluster of voxels is classified into one type of brain tissue by threshold methods. The performance of the algorithm is studied based on both simulated and real T1-weighted 3D brain MR images. Our results show that, compared with other well-known brain image segmentation algorithms, the proposed algorithm can improve the accuracy of the segmentation results substantially.

A Case of Loss of Consciousness due to Epilepsy Diagnosed Using an Implantable Loop Recorder

A Case of Loss of Consciousness due to Epilepsy Diagnosed Using an Implantable Loop Recorder

Safety and reliability of the insertable Reveal XT recorder in patients undergoing 3 Tesla brain magnetic resonance imaging

The independent contribution of brain, spinal cord and gadolinium MRI in treatment decision in multiple sclerosis: A population-based retrospective study.

Objective:This study aims to evaluate the magnetic resonance imaging (MRI) brain patterns among hypoxic-ischemic encephalopathy (HIE) babies who underwent post-cooling MRI brain as well as to correlate the post-cooling brain scoring with patient's neurodevelopmental outcome at 2 years.Subjects and Methods:It was a retrospective cross sectional study carried out at a tertiary university hospital. Record of patients diagnosed with neonatal HIE from 2007 until 2016 who completed 72 h of cooling therapy and had MRI brain within 2 weeks of life were included in this study. A new scoring system by Trivedi et al. that emphasizes on subcortical deep gray matter and posterior limb internal capsule injury were utilized upon MRI assessment, using TW, T2W, and diffusion-weighted imaging (DWI) sequences. Cumulative MRI brain score was obtained and graded as none, mild, moderate, and severe brain injury. The MRI brain scoring was then correlated with patient's 2 years neurodevelopmental outcome using Fisher's Exact Test.Results:A total of 23 patients were eligible of which 19 term neonates were included. 13% of these neonates (n = 3) had mild MRI brain injury grading with 52.2% (n = 12) moderate and 34.8% (n = 8) severe. There was no significant correlation seen between MRI brain grading and developmental outcome at 2 years old (P > 0.05).Conclusion:There was no significant correlation between neonatal MRI brain injury grading and 2 years neurodevelopmental outcome. Nevertheless, the new MRI brain scoring by Trivedi et al. is reproducible and comprehensive as it involves various important brain structures, assessed from different MRI sequences.

Segmentation of bias field induced brain MR images using rough sets and stomped-t distribution

Extraction of the malignant tumor region from the brain magnetic resonance (MR) image is a critical task. As the soft tissues of the brain neoplasm has a lot of variation thus the proper extraction of the malignant tumor and segmenting the affected part from brain MR image is the major part of concern. Malignant brain tumors like Central Neuro Cytoma (CNC), Glioblastoma Multiforme (GBM), Gliomas, Intra Ventricular Malignant Mass and Metastasis are concerned as one of the critical brain tumors of medical science therefore the extraction and appropriate segmentation of such tumor from the brain MR image in their early phase of generation is required. In the past innumerable approaches had applied on brain MR imaging system to figure out the proper abnormality region inside the brain image. The literature gives an idea about various clustering and segmentation approaches that help to identify the abnormal region inside imaging systems based on predefined threshold values. While the selection of proper threshold is again a mind blundering. In this paper a new image segmentation algorithm is proposed which clusters the maximum possible abnormality region based on the probabilistic mutual information. Proposed algorithm is free from any initial selection of threshold value and gives significant results in extraction of the malignant tumor region inside brain MR image.

Understanding the relationships between age-related changes in brain structure and cognitive function has been limited by inconsistent methods for assessing brain imaging, small sample sizes, and racially/ethnically homogeneous cohorts with biased selection based on risk factors. These limitations have prevented the generalizability of results from brain morphology studies. To determine the association of 3.0-T structural brain magnetic resonance (MR) imaging measurements with cognitive function in the multiracial/multiethnic, population-based Dallas Heart Study. Whole-brain, 2-dimensional, fluid-attenuated inversion recovery and 3-dimensional, magnetization-prepared, rapid acquisition with gradient echo MR imaging at 3.0 T was performed in 1645 Dallas Heart Study participants (mean [SD] age, 49.9 [10.5] years; age range, 19-85 years) who received both brain MR imaging and cognitive screening with the Montreal Cognitive Assessment between September 18, 2007, and December 28, 2009. Measurements were obtained for white matter hyperintensity volume, total brain volume, gray matter volume, white matter volume, cerebrospinal fluid volume, and hippocampal volume. Linear regression and a best predictive model were developed to determine the association of MR imaging biomarkers with the Montreal Cognitive Assessment total score and domain-specific questions. High-resolution anatomical MR imaging was used to quantify brain volumes. Scores on the screening Montreal Cognitive Assessment were used for cognitive assessment in participants. After adjustment for demographic variables, total brain volume (P < .0001, standardized estimate [SE] = .1069), gray matter volume (P < .0001, SE = .1156), white matter volume (P = .008, SE = .0687), cerebrospinal fluid volume (P = .012, SE = -.0667), and hippocampal volume (P < .0001) were significantly associated with cognitive performance. A best predictive model identified gray matter volume (P < .001, SE = .0021), cerebrospinal fluid volume (P = .01, SE = .0024), and hippocampal volume (P = .004, SE = .1017) as 3 brain MR imaging biomarkers significantly associated with the Montreal Cognitive Assessment total score. Questions specific to the visuospatial domain were associated with the most brain MR imaging biomarkers (total brain volume, gray matter volume, white matter volume, cerebrospinal fluid volume, and hippocampal volume), while questions specific to the orientation domain were associated with the least brain MR imaging biomarkers (only hippocampal volume). Brain MR imaging volumes, including total brain volume, gray matter volume, cerebrospinal fluid volume, and hippocampal volume, were independently associated with cognitive function and may be important early biomarkers of risk for cognitive insult in a young multiracial/multiethnic population. A best predictive model indicated that a combination of multiple neuroimaging biomarkers may be more effective than a single brain MR imaging volume measurement.

Sepsis often codevelops with brain damage, and the mechanisms underlying sepsis-related brain damage have been elucidated. However, only a few studies have reported the diagnostic imaging assessments for brain damage in sepsis. Therefore, in this study, we analyzed the brain magnetic resonance (MR) imaging (MRI) findings of patients with sepsis. This single-center prospective observational study included 71 patients with sepsis who underwent brain MRI, regardless of the presence or absence of shocks and acute neurological abnormalities. The MR images were classified according to the presence or absence of acute cerebral ischemia and leukoencephalopathy, with normal findings indicating neither condition. The MR images of 18 patients (25.3%) showed acute cerebral ischemia and leukoencephalopathy. Furthermore, 44 patients (62.0%) had only leukoencephalopathy. In terms of patient demographic characteristics and neurological outcomes, significant differences were noted among patients with acute cerebral ischemia findings, those with leukoencephalopathy findings, and those with neither. There were significant differences in age (P = 0.0296), neurological findings (P = 0.0057), number of days in the intensive care unit (P = 0.0239), acute disseminated intravascular coagulation score during hospitalization (P = 0.0363), and the Katz index at discharge or transfer (P = 0.0020) among these groups. Among patients with sepsis, 25.3% showed acute cerebral ischemia findings on brain MRI, regardless of illness severity, including hypoxia and hypotension, and presence of shock. Abnormal MRI findings were also observed in patients without acute brain dysfunction. Importantly, abnormal brain MRI findings were associated with worse neurological outcomes.

Background There is limited published data on the use of implantable loop recorders (ILRs) in patients with long QT syndrome (LQTS). Purpose We sought to evaluate the utility of the ILR in patients who had a diagnosis of LQTS or who had a family history of LQTS. Methods We carried out a retrospective analysis of patients attending an Inherited Cardiac Conditions Clinic who had an active ILR and who had a diagnosis or family history of LQTS. Patient demographics, indications for ILR implantation and clinical outcomes were compiled. Results Nine patients with a diagnosis of LQTS and an active ILR were identified with an average age of 37 years. Genetic results were available for seven patients. Four patients had a confirmed pathogenic mutation (one KCNQ1 and three KCNH2), one patient had a variant of uncertain significance in SCN5A and two patients had negative genetic testing. Indications for implantation were syncope (n=4), recurrent altered consciousness episodes (n=1), assessment of occult arrhythmia or beta blocker complications (n=2), palpitations and dizziness (n=1) and nocturnal dyspnoea and palpitations (n=1). Mean follow-up was 706 days and average age at ILR implant was 35 years. The ILR for three patients was a second device, implanted after end of battery life of the initial ILR. ILR recordings led to a change in management in three patients: finding of paroxysmal atrial fibrillation (n=1), finding of nocturnal QTc of 511ms with a change in medications (n=1) and a pause leading to cessation of beta blocker (n=1). Eleven patients with a family history of LQTS and active ILR were identified. Nine patients were female, and the average age was 44.4 years. Genetic test results were available for five patients. Three patients had a pathogenic mutation in SCN5A, and two patients had negative genetic testing for common LQTS genes. Indications for implantation included syncope (n=5), lightheaded episodes (n=3) and risk assessment in gene carriers (n=3). The mean duration of ILR follow-up was 680 days and average age at ILR implant was 42.5 years. Five patients had no arrhythmia detected during ILR recording, two patients had supraventricular tachycardia identified, in two patients ILR data outruled a sinister cause for a symptomatic episode, one patient had documentation of SVT and brief NSVT which led to referral for electrophysiology study and one patient had no recurrence of symptoms and a second ILR was implanted. Conclusion ILRs were inserted in selected patients with a diagnosis of LQTS or in patients with a family history of LQTS or who were gene carriers. Rationale for ILR implantation included risk stratification, monitoring for occult arrhythmia and rhythm-symptom correlation in symptomatic patients. The ILR impacted management in almost 50% of patients and is considered an important tool in selected patients attending Inherited Cardiac Condition Clinics. Funding Acknowledgement Type of funding sources: None. Table 1

Objective: To study the magnetic resonance imaging (MRI) brain findings in pediatric HIV patients and to correlate them with clinical and immunological staging. Methods: This study was conducted in the Department of Pediatrics of a Teaching Institute of Rajasthan. It was a prospective longitudinal study, conducted over a period of 15 months (April 2008-July 2009). Diagnosis of HIV was confirmed and classified in clinical stages and immunologic stages as per NACO guidelines. MRI brain was done in every patient. Patients with abnormal MRI brain findings were further studied and correlated with clinical findings and CD4+ cell counts. Results: We had total 109 HIV-positive patients registered with us; out of these, 90 were in regular follow-up. Out of these 90 patients, 16 subjects (17.78%) showed abnormal neuroimaging features on MRI brain. No case presented with abnormal MRI features in clinical Stage I and II. 4 were in clinical Stage III, and 12 were in Stage IV. No case presented with abnormal MRI in immunological Stage I and II. 5 cases (31.25%) were in immunological Stage III and 11 (68.75%) in Stage IV. Out of total 90 subjects, only 10 patients had abnormal clinical (neurological) manifestations and rested 80 patients were neurologically and developmentally normal. 6 out of 16 (37.5%) patients with abnormal MRI brain findings did not show any neurological manifestations. The most common MRI brain abnormality noted was cerebral atrophy in 7 (43.75%) cases followed by nonspecific demyelination in 31.25% cases, and ventriculomegaly, nonspecific calcification, and infarcts in 3 (18.75%) subjects each and cerebellar atrophy in 2 subjects. Conclusions: Our study demonstrated that abnormalities of MRI brain increases with increasing immunosuppression and advancing clinical stage. We did not found any significant correlation with age and sex with abnormal MRI brain findings. Importantly, HIV?positive children may present with only abnormal MRI brain findings without any clinical manifestation.

“Closing the loop” on palpitations. A report of unexpected communication between a loop recorder symptom marker and pacemaker

Value of Ambulatory Electrocardiographic Monitoring in Syncope