ABSTRACT
OBJECTIVE: To evaluate feasibility of MRI in patients with non-pacemaker (PM)/ Implantable cardioverter defibrillator (ICD) metallic devices and abandoned leads. BACKGROUND: Relative safety of MRI performed using specified protocol has been established in MR non-conditional PM/ICDs. With limited safety data, many non-PM/ICD metallic devices and abandoned leads continue to be a contraindication for MRI. METHODS: We retrospectively analyzed consecutive patients with extra-cardiac devices, non-programmable cardiac devices, and abandoned leads, who underwent MRI (GE 1.5 Tesla, WI) at a single tertiary care center over a span of 13 years. Scan protocol was designed to maintain specific absorption rate (SAR) < 4.0 W/kg and scan time < 60 minutes. RESULTS: The cohort comprised 127 MRI exams representing 94 patients, with 13 patients having two or more scans. The devices consisted of: 23 vagal nerve stimulators (VNS), 22 implantable loop recorders, 16 spinal stimulators, 5 peripheral nerve stimulators, 3 bladder stimulators, 2 deep brain stimulators, 1 gastric stimulator, 1 bone stimulator, 1 WATCHMAN device, 22 abandoned PM/lCD leads and 1 VNS lead. There was no immediate (peri-MRI exam) morbidity or mortality. Patients did not report any discomfort, palpitations, heating, or sensation of device migration during the exam. Local follow-up data was available in 65% (100% for thoracic imaging) with a mean of 190±475 days (median 13 days). No device malfunction reported during follow-up. CONCLUSIONS: With appropriate precautions, MRI is feasible in patients with extracardiac devices, nonprogrammable cardiac devices, and abandoned leads.
ABSTRACT
BACKGROUND: The mid-femoral head (F50 ) is a common fluoroscopic target for common femoral artery (CFA) puncture during cardiac catheterization. Punctures above the inguinal ligament (marking the proximal end of CFA) increase the risk of retroperitoneal hemorrhage and are classified as high punctures. METHODS: We retrospectively analyzed 114 CT angiograms for the anatomic relationship of the inguinal ligament to the femoral head (FH) and inferior epigastric artery (IEA). We analyzed 114 CT angiograms and 500 femoral angiograms, for the relation of the mid-point of CFA to F50 and F75 (the junction of upper 3/4th and lower 1/4th of FH). RESULTS: The proximal third of femoral head (F33 ) (-1.4 mm) and IEA nadir (-2.9 mm) were closer approximations to the inguinal ligament than the IEA origin (-12.8 mm) or cranial end of FH (-15.2 mm). The inguinal ligament correlated better with the IEA nadir than F33 (R2 = 0.49 vs. 0.001). F75 was a closer approximation for the mid-point of the CFA than F50 (0.3 mm vs. -9.2 mm). Using F75 as the target for CFA puncture carried the lowest risk for non-CFA punctures (18.6%), while using F50 had a 41.2% risk for non-CFA punctures. F75 had an increased risk for low punctures (14.2%) but F50 had a far higher risk for high punctures (36.6%). CONCLUSIONS: The nadir of IEA is the best landmark for identifying the inguinal ligament (the proximal end of CFA) and defining high punctures. F75 is a more accurate target for successful CFA puncture than F50.
