Sinusoidal obstruction syndrome (SOS) is a potentially fatal hepatic veno-occlusive disease-affecting children following bone marrow transplantation (BMT). SOS most likely develops secondary to sinusoidal endothelial damage and subsequent obstruction. The disease can be separated into mild, moderate, and severe forms; almost all patients diagnosed with severe SOS will die from this disease. Children with severe SOS suffer from multi-organ failure with signs and symptoms of portal hypertension (ascites, varices, edema), renal and respiratory failure . Although these children may be few and far between, the mere severity of the disease process and awful prognosis factors are valid reasons for more medical attention. SOS is usually diagnosed via clinical criteria and, despite available prophylaxis and treatment, children continue to die from this devastating disease.

Quantitative shear wave ultrasound elastography with acoustic force radiation imaging is an emerging technology that uses ultrasound pressure waves to provide an estimate of tissue stiffness. This technique is promising for pediatric imaging because it is portable, quick to perform, relatively low cost and involves no ionizing radiation. Acoustic force radiation imaging and ultrasound elastography does not have any increased risks over conventional ultrasound imaging.

This is a single site prospective cohort study that will compare ultrasound elastography to traditional ultrasound parameters in bone marrow transplant patients who are at risk for development of SOS.

• Primary objective: compare sensitivity and specificity of traditional ultrasound parameters and ultrasound elastography of the liver for detecting SOS in BMT patients.
• Secondary objectives: 1. compare sensitivity and specificity of traditional ultrasound parameters and ultrasound elastography of the liver for classifying SOS in BMT patients. 2. compare sensitivity and specificity of traditional ultrasound parameters and ultrasound elastography of the liver for predicting death in BMT patients with SOS (defined as death within 100 days of transplant).
• The validity and reliability of the primary and secondary measures when available. The validity of the measures will be determined by comparing to clinical gold standards of the diagnosis and classification of SOS

Data Collection Procedures

• Candidates for the study will be identified by the Hematology Oncology service when they are admitted for bone marrow transplant.
• A member of the study team will consent that patient and/or their parents once the patient has been identified.
• If the patient consents to the study, an initial limited abdominal ultrasound with Doppler and shear wave elastography will be performed less than one month prior to bone marrow transplant. Demographic and clinical variables will be collected from the chart at the time of initial ultrasound and after date of discharge. Lab value variables will be collected at the time of the initial ultrasound and during all subsequent ultrasounds. Only lab values that have changed since the prior ultrasound will be recorded.
• Multiple shear wave elastography measurements of the liver will be obtained during any post-transplant clinical abdominal ultrasound Data Analyses We will perform two-sided t-tests and nonparametric tests for categorical and continuous data, respectively. Additionally, we will perform a multivariate regression to determine which variables are significantly correlated to death and calculate an odds ratio for each of these variables. If a patient is missing any imaging or clinical data, then this patient will be excluded from those parts of the data analysis, but the rest of their data will still be included in the study.

Inclusion Criteria:

• All patients who are admitted for BMT from the date of study approval until patient accrual is met.

Exclusion Criteria:

• BMT patients who do not end up undergoing transplant during that admission. BMT patients who do not receive any abdominal ultrasounds post transplantation BMT patients who do not consent to the study.

4 months