Liver iron quantification in children and young adults: comparison of a volumetric multi-echo 3-D Dixon sequence with conventional 2-D T2* relaxometry.

BACKGROUND: Magnetic resonance imaging (MRI)-based liver iron quantification is the standard of care to guide chelation therapy in children at risk of hemochromatosis. T2* relaxometry is the most widely used technique but requires third-party software for post-processing. Vendor-provided three-dimensional (3-D) multi-echo Dixon techniques are now available that allow inline/automated post-processing. OBJECTIVE: The purpose of our study was to evaluate the diagnostic accuracy of a volumetric multi-echo Dixon technique using conventional T2* relaxometry as the reference standard in a pediatric and young adult population. MATERIALS AND METHODS: In this retrospective study, we queried the radiology information system to identify all MRIs performed for liver iron quantification from July 2015 to January 2020. All patients had undergone T2* relaxometry on a 1.5-tesla (T) scanner for liver iron concentration (LIC) estimation. In addition, a 3-D multi-echo Dixon was performed using Siemens Healthineers LiverLab (Erlangen, Germany). Two readers independently estimated liver R2* and T2* on the multi-echo Dixon by drawing free-hand regions of interest on the scanner-generated R2* and T2* maps. Conventional T2*-relaxometry-based LIC was the reference standard. We estimated interobserver agreement by concordance correlation coefficient (CCC). We used Bland-Altman analysis and Pearson correlation coefficient (r) to compare LIC by the two methods. RESULTS: Fifty-four MRIs on 38 patients (22 females) were available for analysis. Mean patient age was 11.8 years (standard deviation [SD] 5.3 years). Reference standard LIC ranged 1.1-21.1 (median 6.8) mg/g dry weight of liver. The concordance between readers for T2* estimation using 3-D multi-echo Dixon was substantial (CCC 0.99, confidence interval 0.99-1.00). Bland-Altman plot showed that all observations were clustered around the zero bias line if the LIC average was ≤8 mg/g, and r was very strong (reader 1 r=0.93, reader 2 r=0.92, both P-values <0.001). With increasing LIC, there was a pattern of poor agreement on the Bland-Altman plot, with observations crossing the lower limits of agreement, and r was very weak (reader 1 r=0.05, P-value 0.84; reader 2 r=0.17, P-value 0.44). CONCLUSION: Vendor-based 3-D multi-echo Dixon allows for excellent interobserver correlation in liver T2* estimation. LIC estimated by this method has a very strong correlation with conventional T2* relaxometry if liver iron overload is mild-moderate (LIC ≤8 mg/g).

Alpha-emitter Peptide Receptor Radionuclide Therapy in Neuroendocrine Tumors.

Peptide receptor radionuclide therapy (PRRT) has become mainstream therapy of metastatic neuroendocrine tumors not controlled by somatostatin analog therapy. Currently, beta particle-emitting radiopharmaceuticals are the mainstay of PRRT. Alpha particle-emitting radiopharmaceuticals have a theoretic advantage over beta emitters in terms of improved therapeutic efficacy due to higher cancer cell death and lower nontarget tissue radiation-induced adverse events due to shorter path length of alpha particles. We discuss the available evidence for and the role of alpha particle PRRT.

Adult Primary Sclerosing Cholangitis (PSC) subjects have worse biliary disease at diagnosis compared to pediatric PSC subjects.

INTRODUCTION: Adult Primary Sclerosing Cholangitis (PSC) subjects have worse outcomes compared to pediatric PSC subjects. The reasons for this observation are not completely understood. METHODS: In this single-center, retrospective (2005-17) study we compared clinical information, laboratory data, and previously published MRCP-based scores between 25 pediatric (0-18 years at diagnosis) and 45 adult (19 years and above) subjects with large duct PSC at the time of diagnosis. For each subject, radiologists determined MRCP-based parameters and scores after reviewing the MRCP images. RESULTS: The median age at diagnosis for pediatric subjects was 14 years, while that of adult subjects was 39 years. At the time of diagnosis, adult subjects had a higher incidence of biliary complications like cholangitis and high-grade biliary stricture (27% vs. 6%, p = 0.003) and higher serum bilirubin (0.8 vs. 0.4 mg/dl, p = 0.01). MRCP analysis showed that adult subjects had a higher incidence of hilar lymph node enlargement (24.4% vs. 4%, p = 0.03) at diagnosis. Adult subjects had worse sum-IHD score (p = 0.003) and average-IHD score (p = 0.03). Age at diagnosis correlated with higher average-IHD (p = 0.002) and sum-IHD (p = 0.002) scores. Adult subjects had worse Anali score without contrast (p = 0.01) at diagnosis. MRCP-based extrahepatic duct parameters and scores were similar between groups. DISCUSSION: Adult PSC subjects may have higher severity of disease at diagnosis compared to pediatric subjects. Future prospective cohort studies are required to confirm this hypothesis.

Resolution of Misleading COVID-19 Vaccination-Related Nodal and Splenic FDG Uptake in the Follow-up Study.

ABSTRACT: Newly diagnosed low-grade bilateral breast lymphoma in 63-year-old woman demonstrated intense FDG uptake in the left axillary lymph nodes and the spleen, concerning for lymphomatous involvement. Subsequent ultrasound-guided biopsy did not demonstrate any pathologic left axillary lymph nodes. Further investigation revealed COVID-19 vaccination in the left arm, 5 days prior to the 18 F-FDG PET/CT study. Six-month follow-up 18 F-FDG PET/CT showed resolution of the intense FDG uptake in the left axillary lymph nodes and spleen without any treatment, suggesting a self-remitting acute local and systemic immune response to COVID-19 vaccination.

Chordoma with lung metastases at initial presentation of a pediatric patient.

Chordomas are rare, slow growing malignant tumors derived from notochord remnants that can arise anywhere along the neuronal axis. Chordomas are particularly rare in patients under 20 years of age and tend to be intracranial in location, as opposed to sacrococcygeal in adults. Metastasis at initial presentation is uncommon in all age groups and is exceedingly rare in the absence of local recurrence of the primary tumor. We report a case of advanced clival chordoma with marked nasopharyngeal disease extension and lung metastases at the time of presentation in a pediatric patient.

Advanced colorectal carcinoma with testicular metastasis in an adolescent: a case report.

BACKGROUND: Colorectal carcinoma in the pediatric age group is rare and tends to be very aggressive and present late, due to which it has a very poor prognosis. It may present with distant metastasis; however, metastasis to the testes is very rare and signifies an advanced stage of the disease. Surgery is the only effective modality to cure patients with localized colorectal carcinomas. However, statistics show a higher incidence of unresectable disease and a higher metastasis rate in childhood colorectal carcinomas. We present a case of advanced colorectal carcinoma with testicular metastasis in an adolescent. CASE PRESENTATION: A 15-year-old Indian Hindu boy presented to surgical emergency with signs and symptoms of intestinal obstruction. He also had a history of passing blood and mucus per rectum. On examination he had abdominal distension. On digital rectal examination, a circumferential proliferative growth was felt 1 cm above the anal verge. On scrotal examination, a small nodule was felt in his right testis. In view of intestinal obstruction, he was taken into our emergency operation theater and a diverting loop sigmoid colostomy was performed to relieve the obstruction. A punch biopsy from anorectal growth was taken which suggested signet ring cell adenocarcinoma. Contrast-enhanced computed tomography of his chest, abdomen, and pelvis showed advanced colorectal carcinoma with distant metastasis. Ultrasonography of his testes showed a hypoechoic nodule in the right testis from which a needle aspiration biopsy was done which revealed metastatic adenocarcinoma. CONCLUSIONS: Childhood colorectal carcinomas have a very poor prognosis due to their aggressive nature and late presentation. In spite of all the advances in diagnosis and treatments, the overall long-term survival is still dismal in these patients. Due to the rarity of this disease, screening is not recommended for individuals under the age of 50. Thus, to improve outcome, early diagnosis and treatment is paramount. For that to happen, awareness needs to be created regarding pediatric colorectal carcinoma and its signs and symptoms.