Accuracy of pre-contrast imaging in abdominal magnetic resonance imaging of pediatric oncology patients.

BACKGROUND: Safety concerns are increasingly raised regarding the use of gadolinium-based contrast media for MR imaging. OBJECTIVE: To determine the accuracy of pre-contrast abdominal MR imaging for lesion detection and characterization in pediatric oncology patients. MATERIALS AND METHODS: We included 120 children (37 boys and 83 girls; mean age 8.94 years) referred by oncology services. Twenty-five had MRI for the first time and 95 were follow-up scans. Two authors independently reviewed pre-contrast MR images to note the following information about the lesions: location, number, solid vs. cystic and likely nature. Pre- and post-contrast imaging reviewed together served as the reference standard. RESULTS: The overall sensitivity was 88% for the first reader and 90% for the second; specificity was 94% and 91%; positive predictive value was 96% and 94%; negative predictive value was 82% and 84%; accuracy of pre-contrast imaging for lesion detection as compared to the reference standard was 90% for both readers. The difference between mean number of lesions detected on pre-contrast imaging and reference standard was not significant for either reader (reader 1, P = 0.072; reader 2, P = 0.071). There was substantial agreement (kappa values of 0.76 and 0.72 for readers 1 and 2) between pre-contrast imaging and reference standard for determining solid vs. cystic lesion and likely nature of the lesion. The addition of post-contrast imaging increased confidence of both readers significantly (P < 0.0001), but the interobserver agreement for the change in confidence was poor (kappa 0.12). CONCLUSION: Pre-contrast abdominal MR imaging has high accuracy in lesion detection in pediatric oncology patients and shows substantial agreement with the reference standard for characterization of lesions. Gadolinium-based contrast media administration cannot be completely eliminated but can be avoided in many cases, with the decision made on a case-by-case basis, taking into consideration location and type of tumor.

Awareness of Medical Doctors in Pusat Perubatan Universiti Kebangsaan Malaysia on Diagnostic Radiological Examination Related Radiation Exposure in the Pediatric Population.

BACKGROUND: When exposed to equal radiation doses, the risks for children and adolescents are more significant than for adults. Children grow quickly, and their cells are more sensitive to radiation. After radiation exposure, children have a higher risk of developing malignancies such as leukemia, thyroid abnormalities, and various types of cancers. The healthcare professionals' (in this context referring to medical doctors at all levels) awareness of imaging modalities associated with ionizing radiation is essential to ensure optimal patient management of cooperation in dealing with radiation exposure. Therefore, the present study is aimed to evaluate the awareness of healthcare professionals on medical imaging-related radiation exposure in the pediatric population in our center, Pusat Perubatan Universiti Kebangsaan Malaysia. MATERIALS AND METHODS: A cross-sectional survey was conducted among healthcare professionals using self-administered validated questionnaires in a university hospital for a duration of seven months. Healthcare professionals of all levels participated in this survey. RESULTS: A total of 145 healthcare professionals participated in this study. More than half of the respondents are house officers, 57.2% (n = 83). Results indicated that only 6 out of 145 healthcare professionals who participated in this survey had attended a radiation protection course. This survey showed that 37.2% of the respondents were unaware that chest radiographs would expose patients to ionizing radiation. Finally, results also indicated that senior doctors (21 out of 24 participants) showed better awareness of radiation protection knowledge. CONCLUSIONS: In general, healthcare professionals in our institution are inadequate in awareness of medical radiation exposure, particularly among house officers. However, the awareness of radiation safety and exposure improves with the number of years of clinical practice. We propose that some younger healthcare professionals do not take radiation safety seriously. Moreover, we would like to suggest all healthcare professionals must attend a radiation safety course, as we expect this will improve patient outcomes.

Ultrasound-Determined Residual Gastric Volume after Clear-Fluid Ingestion in the Paediatric Population: Still a Debatable Issue.

Background: Current fasting guidelines are often exceeded in clinical practice, resulting in stressful events during anaesthesia in children. This prospective study compares residual gastric volume after 1 versus 2 h of clear fluid ingestion in fasted children. METHODS: A total of 106 patients were enrolled in the study. Ultrasonography (USG) of gastric antrum (GA) was performed in the supine and right lateral decubitus (RLD) positions. All children fasted from solid food for 6 h. Blackcurrant flavoured drink (3 mL/kg) was given following the measurement of baseline (T0) USG of GA, with follow-ups after 1 (T1) and 2 (T2) hours post-ingestion. Residual gastric volume (RGV) was calculated from the cross-sectional area of GA using a standard formula. Parental satisfaction with their children's behaviour concerning fasting time was recorded. Results: RGV was significantly higher at T1 compared to T2 (p < 0.001). No significant difference was seen between T0 and T2 (p = 0.30). Parental satisfaction was similar at T1 and T2 (p = 0.158). Conclusions: The RGV in paediatric patients after 1 h of clear fluid ingestion was significantly higher than after 2 h of ingestion. There was no difference observed in parental satisfaction concerning the two intervals of fluid fasting. RLD and supine positions can be used reliably to measure the RGV in children.

Tumour-like presentation of brainstem tuberculoma: a lesson learnt.

Brainstem tuberculoma is diagnostically challenging as it lacks clinical clues and imaging mimics a high-grade glioma (HGG). We report the case of an adolescent girl diagnosed with brainstem HGG, who was referred to our centre for Gamma Knife. Initial MRI showed a pontomedullary junction, ring-enhancing lobulated lesion demonstrating distinct central hypointensity on T2-weighted (T2W) and fluid-attenuated inversion recovery (FLAIR) images with extensive vasogenic oedema. An alternative diagnosis of infection was entertained, and biopsy was suggested; however, the parents opted for a trial of alternative treatment. Suboccipital craniotomy and debulking were only performed 3 months later when her symptoms worsened, and MRI revealed enlargement of the lesion. A cheesy 'tumour' was noted intraoperatively; histopathological findings later confirmed chronic granulomatous inflammation. In an endemic area, a high index of suspicion of a tuberculoma is vital specifically in the presence of central T2W/FLAIR hypointensity of a ring-enhancing lesion.

An Evaluation of the Quality of Plain Radiograph Interpretations by Radiology Trainees: A Single Institution Experience.

Introduction: The primary communication between the radiologist and referrer is through the radiological report. However, there are incidents of misinterpretation during radiologist training. Therefore, the present study aimed to evaluate the accuracy level and incidence of interpretation errors for plain radiographs among radiology trainees at our institution. Materials and Methods: The present study retrospectively reviewed 508 reported plain radiographs for one year, and two radiologists subsequently evaluated these plain radiographs. The initial diagnosis by the trainee was compared with the radiologists' evaluation, and the results were categorized as either 'accurate', 'minor discrepancy', or 'major discrepancy'. The data were analyzed concerning the overall performance, year of trainee, anatomic area, patient age group, and radiograph type. A chi-square test was performed, with p < 0.05 indicating statistical significance. Results: The overall accuracy rate was 69%, with minor and major discrepancy rates of 21% and 10%, respectively. There was an insignificant increase in overall accuracy with increased years of training, despite a reduction to 58% accuracy among Year 3 trainees. The accuracy level increased between Year 1, Year 2 and Year 4 by 70%, 71% and 75%, respectively (p > 0.05). The accuracy rates for both the adult and pediatric age groups were not statistically significant. The mobile radiographs showed lower accuracy rate of reporting than the plain radiographs. Conclusion: The radiological trainee interpretations for plain radiographs had an average rating with low discrepancy rates. The Year 3 trainees had the lowest accuracy compared to the other trainee groups. However, the present study suggests the need for further research to determine if the current outcomes are outliers or are indicative of a real phenomenon.

Magnetic resonance imaging T2* of the pancreas value using an online software tool and correlate with T2* value of myocardium and liver among patients with transfusion-dependent thalassemia major.

Objective: Patients with thalassemia major do require lifetime blood transfusions that eventually result in iron accumulation in different organs. We described the usefulness of using magnetic resonance imaging (MRI) T2*imaging values for the evaluation of pancreatic iron load in these patients, and we correlated it with MRI T2* haemosiderosis of the myocardium and liver that has been recognized as a non-invasive assessment of iron overload among patients with thalassemia major. Materials and methods: We conducted a cross-sectional study on 39 patients with thalassemia major in one of the tertiary university hospitals for a 1-year period. Demographic data were collected from the patient's history. MRI T2* of the pancreas, liver, and heart were executed on all patients in the same setting. Objective values of iron overload in these organs were obtained using the MRI post-processing software from online software. Results: A total of 32 (82.1%) patients had pancreatic iron overload including 2 patients (5.1%) with severe iron overload and 15 patients (38.5%) with moderate and mild iron overload, respectively. Nine patients (23.1%) had myocardial iron overload, which included 3 patients (7.7%) who had severe cardiac haemosiderosis. Notably, 37 patients (94.9%) had liver iron overload, which included 15 patients (38.5%) who had severe liver haemosiderosis. There was a moderate positive correlation between the relaxation time of the pancreas and heart haemosiderosis (r = 0.504, P < 0.001). No significant correlation was found between the relaxation time of the pancreas with the liver and the heart with the liver. Conclusion: Pancreatic haemosiderosis precedes cardiac haemosiderosis, which establishes a basis for initiating earlier iron chelation therapy to patients with thalassemia major.

Tracheal cartilaginous sleeve in Pfeiffer syndrome: lesson learnt from its rarity.

Pfeiffer syndrome is a rare inherited craniofacial disorder. Upper airway obstruction is common among patients with Pfeiffer syndrome due to craniosynostosis. They may also present with lower respiratory tract obstruction due to a rare congenital airway malformation called tracheal cartilaginous sleeve (TCS). We report the case of a patient with Pfeiffer syndrome who presented with recurrent bronchopneumonia, discovered incidentally to have TCS via direct visualisation during tracheostomy. Relevant literature for this rare clinical condition are reviewed and discussed. Clinicians should be aware of TCS when encountering patients with craniosynostosis who present with recurrent lower respiratory tract infections. Careful and meticulous investigations should be performed to look for TCS, especially in patients with craniosynostosis.

Case Report: Unusual High-Grade Diffuse Leptomeningeal Glioneuronal Tumor Mimicking Tuberculous Meningitis in a Child From an Endemic Region.

Background: Diffuse leptomeningeal glioneuronal tumor (DL-GNT) is a new entity described in the 2016 World Health Organization (WHO) classification of brain tumors. While DL-GNT is predominantly an indolent tumor that affects young boys, high-grade DL-GNT is unusual and seldom reported in children. Case Presentation: In this report, we describe the challenges and pitfalls associated with diagnosing this high-grade variant in a tuberculosis-endemic region. We highlight the importance of identifying non-typical imaging findings, i.e., non-enhancing cystic lesions with high T2 signal along the leptomeningeal surface, that may expedite the diagnosis of this condition. Histopathologic correlations with MR spectroscopy findings are also discussed. Conclusion: We provide the first clinical imaging report of utilizing MR spectroscopy to distinguish DL-GNT from tuberculosis with histopathologic correlation.

Myelin Oligodendrocyte Glycoprotein (MOG) Optic Neuritis: A Case Series.

Myelin oligodendrocyte glycoprotein (MOG) antibody disease has been recognised as a distinct demyelinating disorder. Optic neuritis has been reported as the most common presentation and manifestation of this spectrum disorder. This is a case series of three MOG optic neuritis patients. Patients involved are female with disease onset ranging between 7- and 37-year-old. Most of these patients experienced symptoms of profound reduced visual acuity with eye pain. All three patients had optic disc swelling upon first presentation and they experienced at least one episode of bilateral simultaneous optic neuritis. Only one patient had demonstrable optic nerve enhancement on magnetic resonance imaging (MRI). Disease was confirmed through positive MOG antibody. Patients typically responded well to intravenous methylprednisolone (IVMP) during acute attack of optic neuritis. However, one patient had suboptimal response to IVMP after multiple relapses. We noted multiple relapses of optic neuritis are common in MOG patients. MOG optic neuritis is a devastating, but treatable condition. Aggressive treatment during acute optic neuritis attack and relapse prevention may favour a good visual prognosis in MOG antibody disease.

Clinical translation of amide proton transfer (APT) MRI for ischemic stroke: a systematic review (2003-2020).

Amide proton transfer (APT) magnetic resonance imaging (MRI) is a pH-sensitive imaging technique that can potentially complement existing clinical imaging protocol for the assessment of ischemic stroke. This review aims to summarize the developments in the clinical research of APT imaging of ischemic stroke after 17 years of progress since its first preclinical study in 2003. Three electronic databases: PubMed, Scopus, and Cochrane Library were systematically searched for articles reporting clinical studies on APT imaging of ischemic stroke. Only articles in English published between 2003 to 2020 that involved patients presenting ischemic stroke-like symptoms that underwent APT MRI were included. Of 1,093 articles screened, 14 articles met the inclusion criteria with a total of 282 patients that had been scanned using APT imaging. Generally, the clinical studies agreed APT effect to be hypointense in ischemic tissue compared to healthy tissue, allowing for the detection of ischemic stroke. Other uses of APT imaging have also been investigated in the studies, including penumbra identification, predicting long term clinical outcome, and serving as a biomarker for supportive treatment monitoring. The published results demonstrated the potential of APT imaging in these applications, but further investigations and larger trials are needed for conclusive evidence. Future studies are recommended to report the result of asymmetry analysis at 3.5 ppm along with the findings of the study to reduce this contribution to the heterogeneity of experimental methods observed and to facilitate effective comparison of results between studies and centers. In addition, it is important to focus on the development of fast 3D imaging for full volumetric ischemic tissue assessment for clinical translation.

Intermittent Suprasternal Neck Mass Caused by Herniation of Ectopic Thymus: Report of Two Cases.

INTRODUCTION: Ectopic thymus is an uncommon cause of neck masses in children that frequently present as lateral cervical swelling especially on the right side. CASE REPORT: We report two cases with atypical clinical presentation of ectopic thymus and superior herniation of normal thymus. Both of the patients manifested as intermittent midline mass at the suprasternal region during Valsalva manuevre. Unique ultrasound features with the location along the thymic descent together with dynamic assessment of the organ movement were essential to reach the correct diagnosis. Conservative approach was considered in these patients considering the necessity of thymus in the process of puberty. CONCLUSION: High index of suspicion is of utmost importance when encounter patient with similar clinical manifestation to avoid unnecessary diagnostic modalities and surgeries. Accurate diagnosis will also alleviate parents' anxiety.

Correlation between MRI characteristics of medulloblastoma with histopathological subtypes and 2-year survival.

OBJECTIVES: The objective of this study is to describe the imaging features of medulloblastoma (MB) and correlate the MR characteristics with the different histological subtype of MB with 2-year survival. MATERIALS AND METHODS: This is a retrospective descriptive study. A total of 29 patients diagnosed with MB from January 2005 to December 2015 were included in this study. The MRI brain and spine studies of these patients were retrieved and reviewed by a pediatric radiologist and a neuroradiologist independently, both blinded from the histological type of the MB. The HPE slides were also retrieved and reviewed by a pathologist. RESULTS: 80% of desmoplastic MB showed the presence of intracranial leptomeningeal seeding and 57.1% of anaplastic MB showed the presence of necrosis. The presence of intracranial leptomeningeal seeding (P = 0.002) and necrosis (P = 0.019) was predictive of the histological subtypes. There is a significant correlation between the enhancement pattern and the 2-year outcome (P = 0.03) with 6 out of 8 patients whose tumors showed minimal enhancement having disease progression within 2 years. A significant correlation was also seen between the presence of necrosis with a poorer outcome (P = 0.03) and between the HPE subtype and 2-year outcome (P = 0.03) with anaplastic MB having the poorest prognosis. CONCLUSION: MR imaging features of intracranial leptomeningeal seeding and the presence of necrosis were correlated with a specific histologic subtype of MB. The enhancement pattern as well as necrosis correlated with 2-year poorer outcome of the disease.