The patient had an implanted Medtronic

The patient had an implanted Medtronic SECURA DR device (atrial lead: Medtronic 6940/52cm, ventricular lead: Medtronic 6945/65cm). The MRI machine used was a GE Signa HDx 1.5-Tesla system. Before performing MRI, we referred to the European position statement on MRI in patients with CIEDs [3]. Because sinus rhythm was maintained and ventricular tachycardia was not experienced, we programmed the pacing mode of the ICD to ODO and turned off all tachycardia detection. A radiology technician, nurse, clinical engineer, radiologist, neurologist, and cardiologist were present in the control booth. A device programmer, an external defibrillator, and an emergency cart were set at the MRI console. An ECG monitor, usually used for ECG synchronization during MRI scanning, and a pulse oximeter were fixed to the patient. The pulse monitor was placed where it could be seen from the control room. Furthermore, a television camera was employed to monitor the patient\'s appearance (Fig. 2). Diffusion-weighted imaging (DWI), T2-weighted (T2W), fluid-attenuated inversion-recovery (FLAIR), and gadolinium-enhanced T1-weighted (Gd-T1W) imaging protocols were performed during the examination. Because remote programming was available with the patient\'s ICD device, the intracardiac rhythm was monitored until the patient entered the room; however, after closing the door, remote monitoring was not possible. After closing the door, ECG monitoring began. However, during MRI scanning, the noise became loud enough to obscure the continuous determination of the new product rhythm by ECG. The pulse oximeter, however, showed the patient\'s pulse continuously during scanning. The patient showed no disturbance during the study, and no ICD parameter changed significantly just after or 1 week after the scan, when compared with the last pre-scan data. Atrial pacing threshold was 1.0V at a 0.4ms pulse width before MRI scanning, 1.0V after scanning, and 0.75V after 1 week. Ventricular threshold was 0.5V at a 0.4ms pulse width, 0.75, and 0.75V before, just after, and 1 week after scanning, respectively. In the same way, intrinsic atrial amplitude was 3.6, 3.6, and 3.8mV, respectively. Intrinsic ventricular amplitude was 15.0, 15.1, and 12.9mV, respectively. Atrial lead impedance was 494, 494, and 475Ω, respectively. Finally, ventricular lead impedance was 437, 475, and 418Ω, respectively. MRI revealed an apparent tumor in the patient\'s medulla and upper cervical spinal cord, with partial extension towards the fourth ventricle (Fig. 3). The post-MRI diagnosis made was that of a neurogliomatous tumor. Following these results, biopsy of the tumor at the fourth ventricle was performed, and the tumor was diagnosed as a grade III–IV astrocytoma. Subsequently, radiotherapy was started in this patient.
Discussion For patients with CIEDs such as PMs or ICDs, MRI could induce adverse effects including tissue heating, failure of capture, runaway PM function, unpredictable reed switch behavior, asynchronous pacing, or damage to PM circuitry [4]. Consequently, MRI is contraindicated in such patients. However, in medical situations such as the case described here, MRI has an indispensable role in diagnosis, especially for brain and cerebrospinal diseases, and is occasionally necessary. In North America and Europe, the use of MRI in patients with PMs and ICDs has been reported in some cases. Two position statements, one from the European Society of Cardiology and the other from the American Heart Association, guide clinicians who are conducting MRI in patients with CIEDs [3,5]. We performed the MRI described in the current study according to both of these statements. We built enough consensuses among the clinicians involved to perform MRI for this patient. We used a 1.5-Tesla MRI machine with a maximum specific absorption rate of 2.13W/Kg, without taking special measures. A pulse oximeter proved very effective in monitoring the patient\'s status during MRI scanning. We used the ODO setting for programming of the ICD device, and no adverse events were observed. Although MRI is thought not to induce severe adverse events when used appropriately in non-PM-dependent patients, great care must be taken with pacing-dependent patients. Furthermore, because rapid stimulation events in a phantom study [3] and device resetting in a human case [2] have been reported, patients at high risk for life-threatening arrhythmia should be subject to particularly vigilant supervision.