Neuroimaging in Pregnancy

Transcription

1 Neuroimaging in Pregnancy January 18, 2014 Sarasota, FL Joshua P. Klein, M.D., Ph.D. Departments of Neurology and Radiology Brigham and Women s Hospital and Harvard Medical School American Society of Neuroimaging 37 th Annual Meeting NO DISCLOSURES American Society of Neuroimaging 37 th Annual Meeting Objectives 1. CT safety issues 2. MRI safety issues 3. CT & MRI contrast safety issues 4. Lactation after contrast 5. Cases 1

2 Pregnancy Endocrine, hemodynamic, endothelial, immunologic, coagulopathic and synaptic changes Alter susceptibility to stroke, hemorrhage, venous thrombosis, demyelination, and other neurologic conditions Continuum 2014, in press Neuroimaging in Pregnancy Though neuroimaging can be performed safely, specific indications, risks, and benefits should be discussed and documented. Discussion can (and should) involve radiologist, OB/GYN, and for CT, a radiation technologist. The effects of radiation exposure are classified into two categories, depending on the intensity of the radiation and the time period of exposure. 1. STOCHASIC EFFECTS 2. DETERMINISTIC EFFECTS 2

3 STOCHASTIC EFFECTS Do not require an absolute exposure threshold to be exceeded in order to cause damage. e.g., mutagenesis and carcinogenesis may be initiated by exposure to any dose of ionizing radiation STOCHASTIC EFFECTS DETERMINISTIC EFFECTS Depend on the total dose of ionizing radiation e.g., cataract formation and infertility are dose-dependent pathologies 3

4 DETERMINISTIC EFFECTS DETERMINISTIC EFFECTS Relevant for our patients who have frequent CT scans - hydrocephalus / NPH / shunts - malignant edema - stroke (ischemic or hemorrhagic) - tumors Total iatrogenic radiation exposure should be tracked. fda.gov/medicaldevices/safety/alertsandnotices/ucm htm 4

5 What is the fetal risk from maternal CT? Fetal radiation dose from a maternal head CT is estimated at <0.01 rad. Fetal radiation dose from a maternal lumbar spine CT is estimated at rad (depending on whether the fetus is directly radiated). In comparison, the exposure to background radiation during the entire gestational period is estimated at 0.23 rad. Radiation exposure MRI safety Devices compatible at 1.0 or 1.5 Tesla may not be compatible at higher field strengths. 5

6 MRI safety Hypothesized risks of MRI to a fetus include: 1) exposure to strong magnetic fields 2) energy deposition leading to increased temperature 3) noise exposure There is no evidence to support fetal harm from MRI. CT Contrast Iodinated contrast should only be given to a pregnant patient in extraordinary circumstances and neonatal thyroid function should be checked. (FDA category B) MRI Contrast Gadolinium contrast should only be used during pregnancy if absolutely necessary, though no adverse effects of gadolinium to the fetus at standard doses have been documented. (FDA category C) 6

7 Lactation The estimated delivery of iodinated contrast and gadolinium contrast agents from mother to infant via lactation is extremely low. Though there is a remote risk of direct toxicity or allergic reaction to breast milk containing these compounds, there is currently no recommendation for ceasing breast feeding after maternal exposure to iodinated or gadolinium contrast agents. Stroke in Pregnancy Ischemia vasculopathy, dissection, atherosclerosis, eclampsia, thrombophilias, APLA syndrome, SCD, cardiomyopathy, endocarditis, paradoxical embolism (PFO), cocaine, heroin, amphetamines, tobacco, PRES Stroke in Pregnancy Hemorrhage vasculopathy, vascular malformations, aneurysms, hemorrhagic transformation of tumor or infarct, venous infarct, septic emboli, cocaine, heroin, amphetamines, tobacco, PRES 7

8 Case 1 A 25F who was 10 weeks pregnant has acute onset dysphasia with fairly well preserved repetition and comprehension. She also had mild L/R confusion and finger agnosia. JAMA Neurol 2013 H: So what s the deal? P: every where thinging days nighing P: Some is where! H: What does that mean? H: You re not making any sense. H: July 24, right? P: J 30 H: July 30? P: Yes H: Oh ok. I m worried about your confusing answers P: But i think H: Think what? P: What i think with be fine JAMA Neurol 2013 MRI / MRA Arch Neurol

9 Case 2 A 20-year-old woman was 4 days post-caesarian delivery when she experienced left hemianesthesia, followed 1 week later by left-sided twitching and then a generalized seizure. 9

10 Case 3 A 38-year-old woman presented with several days of worsening intractable nausea and a throbbing headache at 33 weeks gestation. She was found to be hypertensive, and had elevated liver enzymes and thrombocytopenia. She developed acute-onset right arm and leg weakness. Case 4 A 36-year-old woman presented with nausea, headache, and visual disturbances at 31 weeks gestation and was found to be hypertensive. 10

11 Case 5 A 32-year-old woman who was 8-weeks postpartum presented with sudden onset right occipital headache and hypertension. 11

12 Case 6 Another woman who was postpartum presented with a right-sided throbbing headache. Case 7 A 30-year-old woman underwent placement of an epidural catheter for anesthesia in anticipation of labor. On postpartum day 2, the patient developed back pain and right lower extremity weakness. T1 T2 12

13 Case 8 36-year-old woman presented with headaches and left-sided hearing loss at age 33 and was found to have an extra-axial mass at the left CP angle. Resection via left suboccipital craniotomy revealed a grade 1 meningioma. Following an uncomplicated pregnancy at age 34, the patient experienced recurrence of persistent headaches. post-resection recurrence of headaches Multiple sclerosis in pregnancy Pregnancy can affect relapse rate. Relapses decrease in frequency throughout pregnancy, and increase in the post-partum state for up to 3 months. This may be due to pregnancy-related estriols, which appear to be at higher levels during pregnancy and cause a T2-mediated immune shift in RR-MS patients. 13

14 Multiple sclerosis in pregnancy 30F with painful vision loss OD 2 months postpartum Low back pain in pregnancy Back pain can be due to hormone-induced laxity of spinal ligaments, or to the gravid uterus exerting pressure on the lumbosacral plexus/spine, which itself is due to increased lordosis in pregnancy. Except in cases of trauma where vertebral fracture is suspected, MRI is the best imaging modality for the evaluation of back pain in this population. Definitely obtain MRI if objective deficits are found or if there is a history of spinal instrumentation. Pituitary apoplexy Pituitary gland tends to grow in size and outstrips its vascular supply leading to hemorrhagic and/or ischemic changes. Sudden HA / N / V with endocrine dysfunction may occur, with or without encephalopathy. Visual field cuts and oculomotor pareses can occur as well. Sheehan syndrome (postpartum pituitary necrosis) is hypopituitarism due to ischemia and necrosis related to blood loss and hypovolemic shock during and after childbirth. 14

15 Pituitary apoplexy Statdx.com Lymphocytic hypophysitis Autoimmune condition of the pituitary that typically occurs in late pregnancy or the postpartum period, although it can also be seen in men and non-pregnant women. Lymphocytic infiltration of the pituitary gland and/or infundibulum, causing dysfunction of adjacent normal cells, clinically mimicking the presentation of a pituitary adenoma. Lymphocytic hypophysitis Statdx.com 15

16 Summary 1. Discuss and document indications, risks, and alternatives. 2. Involve the radiologists and obstetricians in planning neuroimaging. 3. MRI preferable to CT in most cases, though not conclusively studied. Summary 4. Scattered versus direct fetal radiation. a. value of shielding the abdomen 5. Delay elective imaging until after pregnancy 6. Iodinated contrast is FDA class B drug. 7. Gadolinium is FDA class C drug. Klein JP, ACP Medicine, 2012 Neuroimaging for the Clinician Bove RM and Klein JP, Neuroradiology in Women of Childbearing Age Continuum, 2014 (in press) 1. ACR practice guideline for imaging pregnant or potentially pregnant adolescents and women with ionizing radiation. Am Coll Radiol; ACR practice guideline for the use of intravascular contrast media. Am Coll Radiol; Kanal E, et al. ACR guidance document for safe MR practices. Am J Roentgenology 2007;188: ACOG committee opinion guidelines for diagnostic imaging during pregnancy. Obstet Gynecol 2004;104: Webb JA, et al; The use of iodinated and gadolinium contrast media during pregnancy and lactation. Eur Radiol 2005;15: