Can Automated 3-Dimensional Dixon-Based Methods Be Used in Patients With Liver Iron Overload?

PURPOSE: Accurate quantification of liver iron concentration (LIC) can be achieved via magnetic resonance imaging (MRI). Maps of liver T2*/R2* are provided by commercially available, vendor-provided, 3-dimensional (3D) multiecho Dixon sequences and allow automated, inline postprocessing, which removes the need for manual curve fitting associated with conventional 2-dimensional (2D) gradient echo (GRE)-based postprocessing. The main goal of our study was to investigate the relationship among LIC estimates generated by 3D multiecho Dixon sequence to values generated by 2D GRE-based R2* relaxometry as the reference standard. METHODS: A retrospective review of patients who had undergone MRI scans for estimation of LIC with conventional T2* relaxometry and 3D multiecho Dixon sequences was performed. A 1.5 T scanner was used to acquire the magnetic resonance studies. Acquisition of standard multislice multiecho T2*-based sequences was performed, and R2* values with corresponding LIC were estimated. The comparison between R2* and corresponding LIC estimates obtained by the 2 methods was analyzed via the correlation coefficients and Bland-Altman difference plots. RESULTS: This study included 104 patients (51 male and 53 female patients) with 158 MRI scans. The mean age of the patients at the time of scan was 15.2 (SD, 8.8) years. There was a very strong correlation between the 2 LIC estimation methods for LIC values up to 3.2 mg/g (LIC quantitative multiecho Dixon [qDixon; from region of interest R2*] vs LIC GRE [in-house]: r = 0.83, P < 0.01; LIC qDixon [from segmentation volume R2*] vs LIC GRE [in-house]: r = 0.92, P < 0.01); and very weak correlation between the 2 methods at liver iron levels >7 mg/g. CONCLUSION: Three-dimensional-based multiecho Dixon technique can accurately measure LIC up to 7 mg/g and has the potential to replace 2D GRE-based relaxometry methods.

Miliary meningeal tuberculosis - an unusual imaging presentation for an early definitive diagnosis.

PURPOSE: Tuberculous meningitis (TBM) causes significant morbidity and mortality in young children. Early treatment can be initiated with magnetic resonance (MR) imaging diagnosis. We present MR-detectable miliary meningeal TB in two patients. CASE 1: A 9-year-old girl developed fevers, cough, lethargy, and seizures. Brain MRI demonstrated multiple, small, T2-dark, rim-enhancing lesions, associated with cranial nerve and leptomeningeal enhancement. CSF showed pleocytosis, low glucose, and high protein. Chest CT showed mediastinal lymphadenopathy, multiple small interstitial lung nodules, and a splenic hypo enhancing lesion. Serial bronchoalveolar lavage studies were Xpert MTB/RIF and acid-fast negative. Endobronchial US-guided biopsy of a subcarinal lymph node was positive for Xpert MTB PCR. She was started on a 4-drug treatment for TBM and dexamethasone. Contact tracing revealed a remote positive contact with pulmonary tuberculosis. CASE 2: A 17-year-old female with Crohn's disease on adalimumab developed refractory ear infections despite multiple courses of antibiotics. She underwent myringotomy, with negative aerobic ear fluid culture. Brain MRI, obtained due to persistent otorrhea, showed multiple, small, round, T2-dark lesions. CSF studies were normal. CT chest, abdomen, and pelvis to assess for disseminated disease showed left upper lobe tree-in-bud nodules, hypoattenuating splenic lesions and a left obturator internus abscess with adjacent osteomyelitis. She underwent CT-guided aspiration of the obturator muscle collection, bronchoscopy with bronchoalveolar lavage, biopsy of two preexisting chronic skin lesions, and ear fluid aspiration. QuantiFERON Gold was positive. Ear fluid was Xpert MTB/RIF assay and acid-fast stain positive. Cultures from the ear fluid, skin tissue, muscle tissue, and alveolar lavage showed growth of acid-fast bacilli. She was started on 4-drug therapy and prednisone. CONCLUSION: Our cases highlight that TBM in many cases remains a diagnostic dilemma - both our patients presented in a prolonged atypical manner. The term miliary TB not only refers to a pattern of interstitial nodules on chest radiographs but also indicates the hematogenous spread of the disease and concurrent pulmonary and extrapulmonary involvement with high risk of TB meningitis. We promote the use of the term miliary meningeal TB - in both cases, the neuroimaging diagnosis of TB preceded both chest imaging and laboratory confirmation of the disease. Miliary meningeal nodules on MRI may have characteristic T2 low signal and may be more conspicuous in children and immunocompromised individuals where background basal meningeal enhancement is less prominent.

Imaging findings of children with PTEN-related hamartoma tumor syndrome: a 20-year multicentric pediatric cohort.

BACKGROUND: PTEN-related hamartoma tumor syndrome results from a mutation in the PTEN gene located at 10q23.31. This syndrome represents a spectrum of different phenotypes of variable expressions, now recognized as part of the same condition. Patients with this mutation have an increased risk of developing a wide range of findings, including malignancies. Although widely described in adults, there are no large series describing the imaging findings in patients before adulthood. Knowledge of the findings seen in children and adolescents with PTEN-related hamartoma tumor syndrome can help guide further management and improve surveillance recommendations. OBJECTIVE: To describe the spectrum of imaging abnormalities in pediatric patients with PTEN-related hamartoma tumor syndrome. MATERIALS AND METHODS: We performed a retrospective, cross-sectional, multicenter study conducted between January 2000 and October 2021 in three tertiary pediatric institutions evaluating the imaging findings in children and adolescents (≤ 18 years) with confirmed diagnoses of a PTEN mutation. For each patient, the imaging findings, histopathology reports, and at least a 2-year follow-up of clinical outcomes for non-operative cases were documented. RESULTS: The cohort included 78 children (37 girls), with a mean age at diagnosis of 7.5 years (range 0 days to 18 years). Benign brain findings included enlarged Virchow-Robin perivascular spaces, white matter changes, developmental venous anomalies, and cerebellar hamartomas. Benign thyroid findings were common, but 5/45 (11.1%) with thyroid abnormalities had a malignant nodule. Soft tissue adipocytic tumors, GI/GU polyps, other soft tissue abnormalities, along with vascular anomalies in various anatomic locations were common. CONCLUSION: Brain abnormalities, benign non-vascular soft tissue abnormalities, and vascular anomalies are commonly seen in children and adolescents with PTEN-related hamartoma tumor syndrome. However, malignancies involving the thyroid gland are not uncommon. Familiarity with the phenotype of PTEN-related hamartoma tumor syndrome in the pediatric population can improve diagnosis and prompt appropriate clinical surveillance of abnormal findings that warrant further management.

How we do it: Cardiac implantable devices are not a contraindication to MRI: time for a paradigm shift.

Magnetic resonance imaging (MRI) is now an indispensable diagnostic tool in medicine due to its outstanding contrast resolution and absence of radiation exposure, enabling detailed tissue characterization and three-dimensional anatomical representation. This is especially important when evaluating individuals with congenital heart disease (CHD) who frequently require cardiac implantable electrical devices (CIEDs). While MRI safety issues have previously limited its use in patients with CIEDs, new advances have called these limitations into question. However, difficulties persist in the pediatric population due to the continued lack of specific safety data both related to imaging young children and the specific CIED devices they often require. This paper discusses MRI safety considerations related to imaging patients with CIEDs, investigates pediatric-specific problems, and describes thorough methods for safe MRI access, highlighting the significance of specialized institutional guidelines.

Quality and Diagnosis on the Lateral View of Pediatric Upper Gastro-Intestinal Series.

BACKGROUND: The standard imaging technique for the diagnosis of intestinal malrotation remains the upper gastro-intestinal series (UGIS). The lateral view is promoted as important for making a diagnosis. For this, the lateral view should be of adequate quality, and radiologists must know the normal appearance as well as the appearance of duodenal variants, as misdiagnosis may lead to unnecessary surgery. OBJECTIVE: We aimed to evaluate the quality, findings including the prevalence of the "descending staircase" configuration and its correspondence to a diagnosis of duodenum redundum. MATERIALS AND METHODS: This was a retrospective study and was conducted in a large tertiary children's hospital in the United States. A retrospective review of UGI fluoroscopy exams in children aged ≤ 18 years between January and December 2018 was performed by a pediatric radiologist. First, the lateral view images/cine-loops were assessed independently, followed by the anteroposterior (AP) view. The studies which were designated to have an adequate lateral view were evaluated for configuration of the duodenum and recorded as: normal, abnormal, or normal variant. Also, the presence of a descending staircase configuration was correlated with an AP view for a diagnosis of duodenum redundum. RESULTS: A total of 26 children (26%) (males:16; females:10) with age range 0 to 16 years had adequate lateral views during UGI exams for inclusion. Of the 26, 18 (69%) were reported as normal, 7 (27%) were reported as having a descending staircase and 1 (4%) was reported as abnormal. The AP view demonstrated 2 abnormal studies (1 malrotation and 1 non-rotation), 6 duodenum redundum and 18 normal exams. The one abnormal lateral duodenum was confirmed as a non-rotation on AP view; the second patient with an abnormal AP view had a normal appearance on the lateral view. CONCLUSIONS: A total of 26% of UGI studies had adequate lateral views for interpretation. Of these, nearly a quarter (23%) demonstrated the descending stair-case sign corresponding to a diagnosis of duodenum redundum on the AP view. If the lateral view had been used alone, there would have been a missed diagnosis in one patient.

State-of-the-art imaging for children with central lymphatic disorders.

Lymphatic imaging plays a crucial role in novel lymphatic interventions, offering valuable insights into central lymphatic drainage. Lymphatic system abnormalities may appear in various pediatric disorders, and accurate imaging is crucial for effective diagnosis and tailored therapeutic interventions. Traditional imaging modalities have offered valuable insights, but the demand for non-invasive, high-resolution techniques has fueled the development of innovative lymphatic imaging methods. In this review, we explore the state of the art in lymphatic imaging specifically within the context of pediatric surgery.

Frequency of abnormal findings on chest radiograph after positive PPD in children and adolescents in an urban setting in the United States.

BACKGROUND: Chest radiographs (CXR) for tuberculosis (TB) screening in children are valuable in high-burden settings. However, less certain in low prevalence contexts. In the United States, positive PPD is sufficient to treat for "latent" TB, or TB infection in asymptomatic patients. OBJECTIVE: We sought to determine frequency of abnormal CXR findings after a positive purified protein derivative (PPD) test at a tertiary pediatric center in the United States. METHOD: A retrospective evaluation was conducted of patients (0-18 years) with a CXR after a positive PPD (e.g., known exposure, employment, migratory requirements or before immunosuppression) between 2011 and 2021. Clinical information, demographics, and reason for PPD were recorded from health record. CXRs were evaluated using initial report and by a pediatric radiologist with special interest in TB and 8 years of experience. RESULT: Of 485 patients, median [interquartile range (IQR)] age 8.5[3.3-14.4], abnormal CXRs were described in 5 (1%). Most common reasons for PPD included: close contact with someone with TB or with high risk for TB. Most patients 373 (76.9%) received treatment for latent TB, and 111 (22.9%) no treatment. One patient (0.2%) received treatment for active disease. Radiographic findings included isolated lymphadenopathy (n = 2), consolidation (n = 1), pleural fluid/thickening (n = 1) and a patient with lymphadenopathy and a calcified nodule (n = 1). CONCLUSION: In our experience, prevalence of chest radiographs findings for patients with positive PPD was very low. Moreover, no cases of severe disease were seen and those with abnormal findings would not merit treatment change under current WHO guidelines.