Presentation on theme: "Whole-Body MRI in the Evaluation of Pediatric Malignancies"— Presentation transcript:
1Whole-Body MRI in the Evaluation of Pediatric Malignancies ACRIN 6660 – Protocol ReviewWhole-Body MRI in the Evaluation of Pediatric MalignanciesMarilyn J. Siegel, M.D.Frederic Hoffer, M.D.Brad Wyly, M.D.Alicia Y. Toledano, ScD
2Aims Primary Aim Secondary Aims Establish non-inferior diagnostic accuracy of whole body MRI compared with conventional imaging studies for detecting metastatic disease for use in staging common pediatric tumors.Secondary AimsDetermine the incremental benefit in accuracy of adding out-of-phase imaging to turbo STIR for detecting distant disease.Obtain preliminary data concerning the relative accuracies of FDG PET and whole body MRI in detecting distant disease.
3Clinical Significance Accurate staging is critical to treatment planning.Conventional techniques have long imaging times and often use sedation and ionizing radiation.If one imaging study can replace established imaging patterns this will have an impact on the care of young cancer patients.
4Imaging BackgroundStudies in adult women with breast cancer show that whole body MRI with turbo STIR can serve as a single examination for stagingSensitivityMRI>>95%Conventional imaging=80%Neuroblastoma Staging: RDOG (Radiology Diagnostic Oncology Group) ResultsMRI effective in detecting marrow metastasesConventional MRI equivalent to combination of CT and bone scintigraphy for stagingLimitations: Whole body images not obtained; newer, faster sequences not usedSiegel MJ et al. Radiol 2002;
5Imaging Background: PET vs MRI 21 patients (51 bone metastases)Small cell tumorsSensitivity90% FDG PET82% whole body MRI (T1- weighted)No STIR or other marrow sensitive image71% scintigraphyMRI and PET may improve detection of bone metastasesDaldrup-Link AJR 2001; 177:229
6Study Overview Required Conventional Studies Experimental Studies Scintigraphy (Bone or MIBG or gallium)Abdominal/Pelvic CT or MRIExperimental StudiesWhole-Body Fast MRIFDG-PET (optional)Expected Accrual Patients in 12 Months50 Neuroblastomas • 30 Other sarcomas60 Rhabdomyosarcomas • 110 LymphomasExpected Stage IV DiseaseNeuroblastomas - 50% (25/100) • Other sarcomas - 20% (6/30)Rhabdomyosarcomas - 16% (10/60) • Lymphomas - 30% (33/110)
7Eligibility Criteria Age 21 years or younger. Proven rhabdomyosarcoma, Ewing’s sarcoma family of tumors, neuroblastoma, Hodgkin’s disease, and non-Hodgkin’s lymphoma, or newly diagnosed mass strongly suspected to represent any of these tumors.All examinations (CT, MRI, scintigraphy, and PET) must be done prior to treatment and within 14 days of each other and within 14 days of any diagnostic or operative procedure.Participants with CT studies, conventional MR, or scintigraphy, performed at outside institutions are eligible if these studies were performed with the same technical standards specified in the protocol (see Appendix V).Signed informed consent by parent or child if older than 18.
8Ineligibility Criteria Contraindications for MRI or CTIncludes active cardiac pacemakers or intracranial vascular clipsLack of parental permission or participant assentPatient has had a previous malignancyPatient has a CNS primary tumorPatient is pregnant or nursingPatient has uncontrolled diabetes mellitus or has controlled diabetes but with a fasting blood glucose value > 200 mg/dL, immediately before the injection of FDG
9Image Interpretation Local Interpretation Images interpreted following practice of each siteInformation may be used for treatment planning as determined on an individual basis by each siteCentral Reader Interpretation10 readers for CT/MRI10 readers for scintigraphyPET, bone scans, galliumReaders blinded to results of other testsAll studies assessed for distant tumor extent
10Positive Findings Positive whole-body MRI or PET at initial staging Additional confirmatory imagingLiver: US, CT or MRIBone: Plain X-rays, CT, MRI or scintigraphy (if not done initially)Brain: CT or MRILung: Thinly collimated CT scansBiopsy also will be suggested if practicalPositive whole-body MRI or PET at initial staging but no biopsy or imaging confirmation of diseaseRepeat imaging with conventional studies recommended at mos.When abnormality is considered highly suspicious for metastasis or when biopsy proof of that lesion is obtained, patient will receive treatment at discretion of the treating physician
11The Sarcomas Mandatory Tests Optional Tests Chest CT (lung mets) Bone scintigraphyWhole-body MRIPlain radiographs if scintigraphy abnormalOptional TestsPETAbdominal CT or conventional MRIBrain CT or MRI
12Neuroblastoma Mandatory Tests Optional Tests Chest or abdominopelvic CT or MRI, depending on site of primary tumorSkeletal and/or MIBG scintigraphy to screen for skeletal metsPlain radiographs if scintigraphy abnormalWhole body MRIOptional TestsPETChest or head CT, brain MRI
13Lymphoma Mandatory Tests Optional Tests Chest or abdominopelvic CT scansGallium scintigraphy if PET not donePlain radiographs if scintigraphy abnormalWhole body MRIOptional TestsPETBrain CT or MRI
14CT Imaging Protocol Bowel Opacification Intravenous Contrast Medium Oral contrast medium whenever possibleIntravenous Contrast MediumNot required for chest CT but can be given at the discretion of the investigatorRequired for abdominal/pelvic CTTechnical FactorsAbdomen, diaphragm to pubic symphysisChest, lung apices through liverMinimum standards: 5 mm collimation, pitch 1.0, lowest mAs and kVp possible
15Conventional MR Imaging Protocol Must be performed for primary soft tissue tumors and may be performed for truncal neuroblastomasAt a minimum, T1-weighted and T2-weighted sequences in at least two planesSection thickness determined by patient size and the intent to cover the entire tumor
16Bone Scintigraphy Imaging Protocol Tc-99m methylene diphosphonate (MDP) (or hydroxyethylene diphosphonate)Approximate dose 280 µCi/kg, with a minimum dose of 2.5 mCiImaging to begin about 2 hours after injectionLarge-field-of-view gamma cameraHigh-resolution collimator for children over age 2 years and a high-resolution or converging collimator for younger children
17Gallium ProtocolIV dose of 140 µCi/kg, with a minimum dose of 0.25 mCiImaging should be performed 3-5 days following injectionSPECT suggested for localization of disease and for distinguishing between normal bowel activity and pathologyLarge-field-of-view multidetector gamma camera with medium-energy collimator recommended
18MIBG ProtocolSaturated potassium iodide solution (SSKI) or other sources of free iodide the day before and 7 days after studyI-123 MIBG preferredDose is µCi/kg, with a minimum dose of 1.0 mCiImages at 24 hours following tracer administration with a large-field-of-view gamma camera equipped with a high-resolution low-or medium energy collimatorAdditional images at 48 hours if possibleIf I-123 MIBG is unavailable, I-131 MIBG can be usedDose is 14 µCi/kg, with a maximum dose of 1.0 mCiImages at 48 hours after tracer administration with a large-field-of-view gamma camera equipped with a high-energy collimatorAdditional images can be obtained at 72 hours, if necessary to clarify findings at 48 hours
19Fast MRI Techniques Whole Body Imaging Vertex to toes Coronal plane imagesBody Coil; phased array coils allowed unless lengthened time of examBreath hold on scans under 30Sec onlyScans performed on a 1.5 TLocalizer scanTurbo STIR (water sensitive image)Out-of-phase (OOPS) better than in phase (IPS) for detecting metastasesImages acquired in 3-4 stationsTotal Imaging time ~ minutes
20OOPS Why OOPS? OOPS Interruption STIR may be overly sensitive and not specific for bone marrow diseaseNeed a T1 weighted sequence for specificitySpin echo T1 too longIn phase (IPS) GRE T1 not sensitive for bone marrow metsOOPS InterruptionOn OOPS T1 if both fat and water then dark signalIf fat only (epiphyses) then brightIf water only (bone metastases) then brightIf bright on STIR and OOPS T1 more likely metastatic bone marrowIf dark on STIR and bright on OOPS then more likely fat only
21Whole Body MRI Technical Factors Patient PositionSupine, arms down at sidesImaging PlaneCoronal, sagittal or multiplane ScoutCoronal STIRCoronal T1 OOPSCoil(s)Body coil*ContrastNoneAnatomic coverageWhole body (cranial vertex to feet)TE (msec)30-77TR (msec)4-7TI (msec)Flip angle8070-75Echo train length7-331Number of slices3-1010-17 slices10-20 slicesSlice thickness (mm)5-104-6Spacing/gap (mm)2-5Field of View (FOV) mm500Matrix (phase x frequency)128 x 256x 256x 256Scan (Acquisition) Time6-20 sec.2-3 minutes15-25 sec.