Magnetic Resonance Imaging Examinations Of Patients Research Articles

Peripheral tear of the triangular fibrocartilage complex: diagnostic accuracy of magnetic resonance imaging and diagnostic performance of the primary and secondary signs.

This study is to assess the diagnostic performance of magnetic resonance imaging (MRI) findings for type 1B triangular fibrocartilage complex (TFCC) tear of the wrist. This study retrospectively enrolled 78 patients to examine the diagnostic performance of preoperative MRI examinations in patients with type 1B TFCC tears. Thirty-nine participants had confirmed type 1B TFCC tear. The control group included 39 patients who were randomly selected from 1157 patients who underwent MRI for wrist pain. Both groups underwent a review of 19 MRI findings by two independent radiologists, and the correlation between each diagnostic finding and type 1B TFCC tear was assessed using the chi-squared test. The 19 MRI findings comprised eight primary signs of abnormalities in the distal or proximal lamina, in conjunction with 11 secondary signs suggestive of abnormalities in the surrounding structures. The TFCC tear group demonstrated a significantly higher incidence of two primary MRI signs, i.e., fiber discontinuity and signal alteration in the distal lamina, as observed by both readers (R1, 74.4% vs. 38.5%, p = 0.003, and 87.2% vs. 43.6%, p < 0.001; R2, 74.4% vs. 35.9%, p = 0.001, and 87.2% vs. 53.8%, p < 0.003, respectively). Reader 2 identified a higher prevalence of two additional primary MRI signs: fiber discontinuity and signal alteration in the proximal lamina (all p < 0.05). None of the 11 secondary MRI signs demonstrated statistically significant associations with type 1B TFCC. MRI manifestations of fiber discontinuity and signal alteration in the distal lamina may provide predictive markers for type 1B TFCC wrist tear.

Detection of Pacemaker and Identification of MRI-conditional Pacemaker Based on Deep-learning Convolutional Neural Networks to Improve Patient Safety.

With the increased availability of magnetic resonance imaging (MRI) and a progressive rise in the frequency of cardiac device implantation, there is an increased chance that patients with implanted cardiac devices require MRI examination during their lifetime. Though MRI is generally contraindicated in patients who have undergone pacemaker implantation with electronic circuits, the recent introduction of MR Conditional pacemaker allows physicians to take advantage of MRI to assess these patients during diagnosis and treatment. When MRI examinations of patients with pacemaker are requested, physicians must confirm whether the device is a conventional pacemaker or an MR Conditional pacemaker by reviewing chest radiographs or the electronic medical records (EMRs). The purpose of this study was to evaluate the utility of a deep convolutional neural network (DCNN) trained to detect pacemakers on chest radiographs and to determine the device's subclassification. The DCNN perfectly detected pacemakers on chest radiographs and the accuracy of the subclassification of pacemakers using the internal and external test datasets were 100.0% (n = 106/106) and 90.1% (n = 279/308). The DCNN can be applied to the radiologic workflow for double-checking purposes, thereby improving patient safety during MRI and preventing busy physicians from making errors.

Co-registration with subtraction and color-coding or fusion improves the detection of new and growing lesions on follow-up MRI examination of patients with multiple sclerosis

PurposeThe purpose of this study was to compare the performance of three magnetic resonance imaging (MRI) reading methods in the follow-up of patients with multiple sclerosis (MS). Materials and methodsThis retrospective study included patients with MS who underwent two brain follow-up MRI examinations with three-dimensional fluid-attenuated inversion recovery (FLAIR) sequences between September 2016 and December 2019. Two neuroradiology residents independently reviewed FLAIR images using three post-processing methods including conventional reading (CR), co-registration fusion (CF), and co-registration subtraction with color-coding (CS), while being blinded to all data but FLAIR images. The presence and number of new, growing, or shrinking lesions were compared between reading methods. The reading time, reading confidence, and inter- and intra-observer agreements were also assessed. An expert neuroradiologist established the standard of reference. Statistical analyses were corrected for multiple testing. ResultsA total of 198 patients with MS were included. There were 130 women and 68 men, with a mean age of 41 ± 12 (standard deviation) years (age range: 21–79 years). Using CS and CF, more patients were detected with new lesions compared to CR (93/198 [47%] and 79/198 [40%] vs. 54/198 [27%], respectively; P < 0.01). The median number of new hyperintense FLAIR lesions detected was significantly greater using CS and CF compared to CR (2 [Q1, Q3: 0, 6] and 1 [Q1, Q3: 0, 3] vs. 0 [Q1, Q3: 0, 1], respectively; P < 0.001). The mean reading time was significantly shorter using CS and CF compared to CR (P < 0.001), with higher confidence in readings and higher inter- and intra-observer agreements. ConclusionPost-processing tools such as CS and CF substantially improve the accuracy of follow-up MRI examinations in patients with MS while reducing reading time and increasing readers' confidence and reproducibility.

3 Tesla magnetic resonance imaging in patients with cardiac implantable electronic devices: a single centre experience.

Three Tesla (T) magnetic resonance imaging (MRI) provides critical imaging information for many conditions. Owing to potential interactions of the magnetic field, it is largely withheld from patients with cardiac implantable electronic devices (CIEDs). Therefore, we assessed the safety of 3T MRI in patients with '3T MRI-conditional' and 'non-3T MRI-conditional' CIEDs. We performed a retrospective single-centre analysis of clinically indicated 3T MRI examinations in patients with conventional pacemakers, cardiac resynchronization devices, and implanted defibrillators from April 2020 to May 2022. All CIEDs were interrogated and programmed before and after scanning. Adverse events included all-cause death, arrhythmias, loss of capture, inappropriate anti-tachycardia therapies, electrical reset, and lead or generator failure during or shortly after MRI. Changes in signal amplitude and lead impedance were systematically assessed. Statistics included median and interquartile range. A total of 132 MRI examinations were performed on a 3T scanner in 97 patients. Thirty-five examinations were performed in patients with 'non-3T MRI-conditional' CIEDs. Twenty-six scans were performed in pacemaker-dependent patients. No adverse events occurred during or shortly after MRI. P-wave or R-wave reductions ≥ 50 and ≥ 25%, respectively, were noted after three (2.3%) scans, all in patients with '3T MRI-conditional' CIEDs. Pacing and shock impedance changed by ± 30% in one case (0.7%). Battery voltage and stimulation thresholds did not relevantly change after MRI. Pending verification in independent series, our data suggest that clinically indicated MRI scans at 3T field strength should not be withheld from patients with cardiac pacemakers or defibrillators.

Magnetic resonance imaging scans in patients with dorsal root ganglion stimulation.

Patients fitted with a neurostimulator face a greater need to undergo magnetic resonance imaging (MRI) scans. Given the lack of literature in this regard, this study aims to review our experience with MRI examinations on patients implanted with a dorsal root ganglion stimulation (DRG-S) system and their potential adverse events. We conducted a retrospective analysis of the prospective treatment documentation gathered from November 2011 to October 2020. We identified 259 MRI registrations for patients with an implanted neurostimulation system; the MRI examinations were performed using a 1.5 Tesla MRI system in accordance with a structured scheme. Among the 259 MRI registrations identified in this study, 28 corresponded to patients with an implanted DRG-S system. In 2 cases, no MRI scan was performed, and thus, only 26 MRI examinations were evaluated in detail. The DRG-S device was approved for the requested MRI scans in only 2 of these 26 cases (7.7%). In addition, 2 minor adverse events (syncopal episode and connection problem) were identified, and only the second problem (3.8%) was related to neurostimulator operation. Necessary MRI examinations in patients with DRG-S systems are rarely covered by the European CE/US Food and Drug Administration (CE/FDA) approval. Although the manufacturer recommendations are against the use of MRI in patients with implanted DRG-S in certain conditions, we performed these scans without causing injury to the patient or damaging the device. Given that data on safety are limited, MRIs should be conducted study related. We provide recommendations for the procedure that should be followed when an MRI is needed urgently.

The prevalence of sacroiliitis on abdominal MRI examinations of patients with Takayasu arteritis.

Takayasu arteritis (TA), a systemic large-vessel vasculitis, was reported to have high incidence of spondyloarthropathy. To evaluate the prevalence of inflammatory sacroiliitis in patients with TA that underwent abdominal/pelvic magnetic resonance imaging (MRI) examinations as part of their vasculitis work-up. Consecutive abdominal/pelvic MRI examinations of 34 patients with TA fulfilling the 1990 ACR criteria and 34 age- and gender-matched controls performed between 2008 and 2020 were retrospectively reviewed for the presence sacroiliitis. The presence of active and structural lesions was scored twice (with a one-month interval between reads) by one reader. Structural lesions were also evaluated on computed tomography, when available, and correlated to MRI findings. Clinical data were extracted from the patients' clinical files. MRI scores were compared between the study and control groups and correlated with the clinical data. Sacroiliitis was evident in 11.7% of the TA group examinations compared to 0.3% in the control group (P = 0.6). Participants with TA had significantly more erosions and fat deposition compared to the control group (Study: 0.01/0.03, Control: 0/0, P = 0.03/0.003, respectively). However, mean sacroiliitis score was not significantly different (Study: 1.06, Control: 0.78, P = 0.015). Of the four patients with TA and sacroiliitis, 3 (75%) had a diagnosis of inflammatory bowel disease (IBD). Sacroiliitis was detected in 11.7% of abdominal MRI examinations of patients with TA, 75% of which had associated IBD, suggesting that both IBD and sacroiliitis should be routinely screened in the TA population as their presence may influence treatment decisions.

The Outcome of Epidural Injections in Lumbar Radiculopathy Is Not Dependent on the Presence of Disc Herniation on Magnetic Resonance Imaging: Assessment of Short-Term and Long-Term Efficacy

Lumbar radiculopathy is a condition with major physical, social, and economic consequences. Despite its favorable prognosis, the burden can be significant. In this study, we aimed to determine the value of magnetic resonance imaging (MRI) and the efficacy of transforaminal epidural injections (TEIs) in patients with lumbar radiculopathy secondary to lumbar disc herniation (LDH) and other causes (non-LDH). Patients with lumbar radiculopathy were reviewed for radiologic diagnosis based on MRI. For patients receiving TEI therapy, response after 6-8 weeks (short-term) and 16 weeks (long-term), number of injections, subsequent surgery, and patient outcome were evaluated. Treatment response was assessed by patient-reported symptom relief and numeric rating scale pain scores. Overall, 66% of MRI examinations showed a clinically relevant LDH. A total of 486 of 1824 patients received TEI, of whom one third did not show LDH. Of patients, 70% reported a short-term effect with significant pain reduction and 44% reported a long-term effect. No significant differences were observed between the LDH and non-LDH groups. Of patients, 59% required multiple injections and reported similar efficacy compared with patients treated with a single injection. A considerable part of MRI examinations in patients with lumbar radiculopathy do not show a clinically relevant LDH. Regardless of the radiologic diagnosis, most patients treated with TEI benefit in both the short-term and the long-term after a single-injection or multiple-injection regime. Subsequent injections are advisable if the effect from the first injection is unsatisfactory or wears off. MRI examination before TEI therapy may be redundant, which allows for expedition of this treatment.

Utilization of Magnetic Resonance Imaging by Comorbidity of Patients with Dementia.

Dementia produces major clinical and social problems that have catastrophic consequences for patients and their families. Dementia also complicates clinical care for other co-existing medical conditions. Magnetic Resonance Imaging (MRI) utilization is increasingly used for diagnostic purposes, such as early diagnosis of dementia and special examination of dementia. This study analyzed the utilization status and factors affecting use of MRI examination of patients with dementia using the Charlson Comorbidity Index (CCI). We used data from the Korean National Hospital Discharge In-depth Injury Survey (KNHDS) for three years, from 2013 to 2015, investigated by Korea Centers for Disease Control and Prevention (KCDC). The subjects of the study were 643 patients whose primary diagnosis code according to the International Classification of Disease (ICD) is F00–F03 (dementia in Alzheimer’s disease, vascular dementia, unspecified dementia, etc.). As independent variables, we used sex, age, type of insurance, the admission route, length of stay, result of treatment, number of hospital beds, and the hospital’s location. In this study, the independent variables affecting MRI examination of dementia patients were length of stay, hospital location, and CCI. The ratio of MRI examination of patients with dementia in which the CCI was 1, was significantly higher by 1.757 times than in cases where the CCI was 0. Hence, it can be used to provide basic data for formulating health care policy for dementia patients by studying their overall situation.

Complications and imaging artifacts related to MRI in patients with intramedullary osteosynthesis after proximal femur fracture.

Fractures of the proximal femur is one of the most frequent human injuries, and most of the patients are treated with osteosynthesis, such as intramedullary nails. These patients often require magnetic resonance imaging (MRI) scans in their further lives due to various reasons. This raises the question of whether complications with implanted osteosynthesis material such as implant loosening, burning, dislocation, or other complications are to be expected or whether an MRI examination is even suitable with regard to imaging artifacts. The aim of this retrospective study was to investigate the rate and type of complications after MRI examinations in patients with inserted intramedullary osteosynthesis device. Furthermore, artifacts in MRI caused by this device were assessed. MRI scans of the head (20 of 62), spine (20 of 62), pelvis (10 of 62), and lower extremity (6/62) were performed. Three of the 62 patients received an MRI of the abdomen, and 2 of the 62 patients received an MRI of the thorax and the upper extremity. Of the 62 patients, noneexperienced complications during the immediate examination. Similarly, none of the patients showed early complications within the first 2 weeks after MRI. In our long-term follow-up examination, no long-term complication after MRI was observed in the recorded 15 patients. Artifacts were found in 14 patients: in MRI scans of the pelvis (10/10), of the abdomen (2/3), and of the lower extremity (2/6). There were no complications during the MRI scan, in the first 2 weeks after MRI, or in the recorded long-term results. MRI with an enclosed intramedullary nail provided good image quality unless the immediate implant site was imaged. MRI diagnosis is thus possible in patients with an inserted intramedullary nail. The inserted intramedullary nail should therefore not be an exclusion criterion when sectional imaging with MRI is required.

Dentures wearing reduce motion artifacts related to tongue movement in magnetic resonance imaging

PurposeTongue movement with unstable swallowing cause artifacts on magnetic resonance imaging (MRI). This may be associated with loss of occlusal support. This study aimed to clarify whether motion artifacts can be mitigated by denture wearing during MRI examination in patients without occlusal support, and whether denture wearing affect tongue stability, form, and position were also evaluated. MethodsTen subjects without occlusal support (6 male, 4 female; mean age 73.20±10.12 years) participated in the study. MRI was performed with dentures worn (DW), followed with removal of dentures (NDW). Luminance standard deviation (LSD) was measured in regions of interest in the axial and sagittal planes. The position of the base of the tongue (TB), tip of the tongue apex (TA), and tongue's long diameter (TLD) were compared between DW and NDW. ResultsNDW evoked ambiguous MR images in the axial and sagittal planes compared with DW. There were significant differences in LSD between DW and NDW in both the axial (p=0.047) and sagittal planes (p=0.02). No significant difference in the position of TB were observed (p=0.78). The position of TA was significantly more protruded with DW (p=0.007). Also, TLD was significantly longer with DW (p=0.001). ConclusionsResults of this study suggest that wearing the dentures during MRI examination reduces motion artifacts in edentulous patients without occlusal support, and maintained the normal form of the tongue during imaging.

Abbreviated protocol for breast MRI: Are multiple sequences needed for cancer detection?

ObjectiveTo evaluate the ability of an abbreviated breast magnetic resonance imaging (MRI) protocol, consisting of a precontrast T1 weighted (T1W) image and single early post-contrast T1W image, to detect breast carcinoma. Materials and methodsA HIPAA compliant Institutional Review Board approved review of 100 consecutive breast MRI examinations in patients with biopsy proven unicentric breast carcinoma. 79% were invasive carcinomas and 21% were ductal carcinoma in situ. Four experienced breast radiologists, blinded to carcinoma location, history and prior examinations, assessed the abbreviated protocol evaluating only the first post-contrast T1W image, post-processed subtracted first post-contrast and subtraction maximum intensity projection images. Detection and localization of tumor were compared to the standard full diagnostic examination consisting of 13 pre-contrast, post-contrast and post-processed sequences. ResultsAll 100 cancers were visualized on initial reading of the abbreviated protocol by at least one reader. The mean sensitivity for each sequence was 96% for the first post-contrast sequence, 96% for the first post-contrast subtraction sequence and 93% for the subtraction MIP sequence. Within each sequence, there was no significant difference between the sensitivities among the 4 readers (p=0.471, p=0.656, p=0.139). Mean interpretation time was 44s (range 11–167s). The abbreviated imaging protocol could be performed in approximately 10–15min, compared to 30–40min for the standard protocol. ConclusionAn abbreviated breast MRI protocol allows detection of breast carcinoma. One pre and post-contrast T1W sequence may be adequate for detecting breast carcinoma. These results support the possibility of refining breast MRI screening protocols.

Intramedullary fat globules related to bone trauma: a new MR imaging finding.

The purpose of this study is to describe intraosseous fat globules related to bone trauma that are detectable with magnetic resonance imaging (MRI), to define the relationship of this finding to fracture and bone contusion, to establish the frequency and associated findings. A proposed pathogenesis is presented. We retrospectively reviewed 419 knee MRI examinations in patients with a history of recent injury and MRI findings of fracture or bone contusion. As a control population, 268 knee MRI examinations in patients without MRI findings of recent bone injury were also reviewed. Eight of 419 (1.9%) patients with acute or subacute knee injury with positive findings of osseous trauma on MRI demonstrated intraosseous fat globules. The mean age of patients with fat globules was greater than that of those without fat globules, and the finding was more commonly seen in women. Fat globules were hyperintense to the normal fatty marrow present elsewhere in the bone on TI-weighted imaging and had a surrounding halo of high signal intensity on fluid-sensitive imaging. Intramedullary fat globules related to bone injury visible on MRI are thought to be due to coalesced fat released by the necrosis of fatty marrow cells. The pathogenesis is supported by histologic studies of fat globules related to osteomyelitis, bone contusions and fractures. As the medullary cavity of long bones in older patients contains more fat than hematopoetic bone marrow, it is likely that this finding is more common with advancing age.

Magnetic resonance imaging and devices: a mesmerising combination.

Magnetic resonance imaging (MRI) is the fastest growing standard of care in diagnostic imaging. Because of its unique properties such as noninvasive accurate assessment of left ventricular (LV) volumes and regional LV wall motion abnormalities, quantification of flow and tissue characterisation, MRI utilisation in the US is still growing at approximately 3 % per year [1]. Moreover, indications for MRI may expand due to innovative techniques such as magnetic resonance angiography (MRA) or the use of targeted contrast agents. This increased usage of MRI is paralleled by an annual growth of de novo pacemakers (>700,000) and implantable cardio-defibrillators (>200,000) [2]. Since many recipients of pacemakers and ICDs have substantial comorbidities, it is estimated that up to 75 % will develop an indication for MRI examination during further life [3, 4]. The hazards of MRI examination in patients with pacemakers and ICDs are a consequence of the techniques used [5]. First the static magnetic field may yield mechanical forces on ferromagnetic components and may have unpredictable magnetic sensor activation. Second, the modulated radiofrequency (RF) field may cause heating of cardiac tissue adjacent to the lead tip, may induce life-threatening arrhythmias and may interact with the device leading to over- or under-sensing. Third, the gradient magnetic field may induce life-threatening arrhythmias or may cause over- or under-sensing. Finally, combined field effects can alter device function or lead to electronic reset. Electrical reset may have major implications since it can cause pacemaker inhibition or induce fatal tachyarrhythmias. Currently, MRI conditional CIEDs have become available in which the risk of an electronic reset is significantly reduced by adaptations in the device. Moreover, lead design has been improved to avoid tip heating. In this issue of the Netherlands Heart Journal Van der Graaf and co-workers give an excellent overview of the current status of MRI in patients with cardiac implantable electronic devices (CIED) [6]. They underline that although safety in these patients who are scheduled for MRI examination has traditionally been regarded a major issue, the recently published European Society of Cardiology (ESC) guidelines express a different view [7]. These 2013 guidelines state that MRI can be safely performed irrespective of the properties of the CIED, the type of MRI examination or patient characteristics such as presence or absence of underlying rhythm, as long as safety restrictions are met. Differences in risk between chest and non-chest MRI are not mentioned. Moreover, the absolute number of patients on which these guidelines are based is limited. A total of seven studies each report on small numbers of chest MRIs. For example, in the study by Sommer and co-workers on MRI in 51 patients only 5 had chest scanning, and Naehle and colleagues reported on 18 CIED patients but only 8 patients had examinations of the chest [8, 9]. In a larger study, Mollerus evaluated 127 MRI scans in 103 patients of which 62 were chest MRIs [10]. No threshold elevation was found, but both sensing amplitudes and pacing impedances significantly changed. By far the largest study was conducted by Nazarian and co-workers in 438 patients with pacemakers and ICDs [11]. In this study, pacemaker-dependent patients with an ICD were excluded. In 89 patients chest MRI was performed. Three of the 438 patients had an electrical reset (power-on-reset) leading to occasional pacing inhibition in 2 patients. There were no symptomatic events in these non-pacemaker dependant individuals. In the studies mentioned CRT devices are strongly underrepresented. Thus, current guidelines concerning MRI in patients with CIED are based on a limited number of relatively small studies in patients with a wide range of devices and leads, typically excluding pacemaker-dependent patients as well as patients with CRT devices. The evidence for safety of chest MRI is based on less than 200 patients and potentially associated arrhythmias are still reported. Although the recent guidelines have become more lenient and major complications have rarely been reported, risk assessment in patients with CIED is not straightforward. We would therefore advocate a prudent approach in scheduling patients with CIED for MRI examination, especially those with older type or CRT devices and when using newer (3T) MRI suites. MRI provides mesmerising image quality, but mesmerisation of CIED should be avoided.

MRI and cardiac implantable electronic devices; current status and required safety conditions.

Magnetic resonance imaging (MRI) has evolved into an essential diagnostic modality for the evaluation of all patient categories. This gain in popularity coincided with an increase in the number of implanted cardiac implantable electronic devices (CIEDs). Therefore, questions arose with regard to the MRI compatibility of these devices. Various investigators have reported the harmless performance of MRI in patients with conventional (non-MRI conditional) devices. The recently published European Society of Cardiology (ESC) guidelines on cardiac pacing and cardiac resynchronisation therapy (CRT) indicate that MRI can be safely performed in patients with an implanted pacemaker or ICD (MRI conditional or not), as long as strict safety conditions are met. This is a major modification of the former general opinion that patients with a pacemaker or ICD were not eligible to undergo MRI. This review paper attempts to elucidate the current situation for practising cardiologists by providing a clear overview of the potential life-threatening interactions and discuss safety measures to be taken prior to and during scanning. An overview of all available MRI conditional devices and their individual restrictions is given. In addition, an up-to-date safety protocol is provided that can be used to ensure patient safety before, during and after the scan. Key points • Historically, MRI examination of patients with a CIED has been considered hazardous. • Ongoing advances in technology and increasing usage of MRI in clinical practice have led to the introduction of MRI conditional CIEDs and to more lenient regulations on the examination of patients with non-conditional CIEDs. • MRI investigations can be performed safely in selected patients when adhering to a standardised up-to-date safety protocol.

The Dark Lymph Node Sign on Magnetic Resonance Imaging

The purpose of this study was to describe a characteristic magnetic resonance imaging (MRI) appearance of lymphadenopathy in sarcoidosis--the dark lymph node sign (DLNS)--and to determine its prevalence in a retrospective review of cardiopulmonary MRI examinations obtained in patients with sarcoidosis. Fifty-one adult patients with a clinical history of sarcoidosis were evaluated with thoracic MRI during a 15-month span; 29 patients were men, and 22 patients were women. The average age of patients was 53.7±11.2 years. Patients were considered to have the DLNS on MRI if mediastinal or hilar lymph nodes demonstrated internal low intensity with a peripheral circumferential rim of hyperintensity (relative to paraspinal muscle) on post-gadolinium volume-interpolated 3-dimensional gradient echo (3D-GRE/VIBE) and fat-saturated T2-weighted fast spin echo (T2-FSE/BLADE) sequences. Univariate analyses and a logistic regression were used to determine how variables of interest related to the DLNS. Of the 51 patients with sarcoidosis, 49% (25 patients) demonstrated the DLNS. Nodal calcification was present on computed tomography in 45.7% (16/35) of patients with computed tomography scans obtained within 90 days of MRI. The DLNS sign was not more common in those with nodal calcification. When the DLNS occurred in conjunction with calcified nodes, the extent of hypointensity on MRI was not strictly limited to the calcified portions of the lymph node in 71.4% (5/7) of such cases. The DLNS is commonly present on MRI examinations of patients with sarcoidosis, occurring in approximately half of the participants in our study.

Spinal magnetic resonance imaging with reduced specific absorption rate in patients harbouring a spinal cord stimulation device - A single-centre prospective study analysing safety, tolerability and image quality

Spinal cord stimulation (SCS) is an accepted treatment in patients with failed back surgery (FBS), complex regional pain syndrome (CRPS) and persistent radicular pain following surgery. In order to avoid patient hazards or device malfunction manufacturers advise to abstain from magnetic resonance imaging (MRI) in patients with implanted electrodes or pulse generators. In a prospective study, 13 patients harbouring an implanted Medtronic Spinal Cord Stimulation (SCS) device underwent MRI (1.5 T) of the lumbar (n=13), the cervical (n=2) or the thoracic spine (n=1) following the development of new spinal symptoms. An adapted MRI protocol was used limiting the transmitted energy and specific absorption rate. Tolerability and safety were assessed by means of a standardized patient evaluation form documenting pain on a visual analogue scale (0-10), neurologic deficit, and discomfort during the scan. In addition, overall satisfaction with the examination procedure was rated on a Likert scale (1-5). Image quality was rated independently and blinded to the presence of a SCS device by the radiologist and the surgeon as equivalent, superior or inferior compared to the standard spine MRI examination. None of the 13 patients investigated by the modified spinal MRI protocol experienced new neurological deficits, worsening of symptoms or a defect/malfunction of the implant device. Three patients (23.1 %) reported transient warm sensation in the location of the electrode and in one case intermittent slight tingling in the lower extremities. Overall satisfaction with the examination was 1.13 ± 0.34 according to Likert scale (1-5). The image quality was rated - not statistically significant - slightly inferior to standard lumbar spine imaging (0.82 ± 0.54) with a kappa value of 0.68 between the two investigators. MRI examinations detected relevant and new lesions in 9 (69.2 %) patients which affected treatment in 8 (61.5 %) individuals. Using a protocol with a reduced specific energy absorption rate, spinal MRI examinations in patients with SCS can be considered safe. The current view that neurostimulators are a general contraindication to MR examinations has to be reconsidered in patients with new or progressive spinal symptoms.

Determining the risks of clinically indicated nonthoracic magnetic resonance imaging at 1.5 T for patients with pacemakers and implantable cardioverter-defibrillators: Rationale and design of the MagnaSafe Registry

Until recently, the presence of a permanent pacemaker or an implantable cardioverter-defibrillator has been a relative contraindication for the performance of magnetic resonance imaging (MRI). A number of small studies have shown that MRI can be performed with minimal risk when patients are properly monitored and device programming is modified appropriately for the procedure. However, the risk of performing MRI for patients with implanted cardiac devices has not been sufficiently evaluated to advocate routine clinical use. The aim of the present protocol is to prospectively determine the rate of adverse clinical events and device parameter changes in patients with implanted non-MRI-conditional cardiac devices undergoing clinically indicated nonthoracic MRI at 1.5 T. The MagnaSafe Registry is a multicenter, prospective cohort study of up to 1500 MRI examinations in patients with pacemakers or implantable cardioverter-defibrillators implanted after 2001 who undergo clinically indicated nonthoracic MRI following a specific protocol to ensure that preventable potential adverse events are mitigated. Adverse events and changes in device parameter measurements that may be associated with the imaging procedure will be documented. Through August 2012, 701 MRI studies have been performed, representing 47% of the total target enrollment. The results of this registry will provide additional documentation of the risk of MRI and will further validate a clinical protocol for screening and the performance of clinically indicated MRI for patients with implanted cardiac devices.

Acute Appendicitis on Abdominal MR Images: Training Readers to Improve Diagnostic Accuracy

To determine if training with direct feedback helps to improve the diagnostic performance of inexperienced readers in the detection of appendicitis on magnetic resonance (MR) images. The institutional review board approved this retrospective study and waived the requirement for informed consent. Nine radiologists and eight residents without experience in evaluating MR images for acute abdominal conditions evaluated a training set of images from 100 MR imaging examinations of patients suspected of having appendicitis and received direct feedback after each evaluation. An expert panel made a diagnosis of appendicitis in 45 patients and an alternative diagnosis in 55 patients on the basis of histopathologic examination and follow-up. Readers recorded two diagnoses: the first after viewing images from conventional MR sequences (half-Fourier rapid acquisition with relaxation enhancement and true fast imaging with steady-state precession) and the second after viewing diffusion-weighted (DW) MR images. Reader sensitivity and specificity were calculated per set of 25 cases. The average reader sensitivity for detecting appendicitis improved significantly after training (0.82 vs 0.92, P = .003); the average specificity improved nonsignificantly (0.82 vs 0.88, P = .10). Sensitivity for radiologists increased from 0.81 in the first set of 25 cases to 0.91 in the last set, and specificity improved from 0.82 to 0.85. For residents, sensitivity increased from 0.82 to 0.94, and specificity increased from 0.82 to 0.91. Sensitivity improved from 0.80 to 0.87 (P < .001) in all readings combined when DW images were read in addition to conventional MR images. Diagnostic accuracy of inexperienced readers in the evaluation of abdominal MR images for acute appendicitis improved after training with direct feedback, and the addition of DW images improved reader sensitivity.

Costs and effectiveness of a brief MRI examination of patients with acute knee injury

The aim of this study was to assess the costs and effectiveness of selective short magnetic resonance imaging (MRI) in patients with acute knee injury. A model was developed to evaluate the selective use of MRI in patients with acute knee injury and no fracture on radiography based on the results of a trial in which 208 patients were randomized between radiography only and radiography plus MRI. We analyzed medical (diagnostic and therapeutic) costs, quality of life, duration of diagnostic workup, number of additional diagnostic examinations, time absent from work, and time to convalescence during a 6-month follow-up period. Quality of life was lowest (EuroQol at 6 weeks 0.61 (95% CI 0.54-0.67)); duration of diagnostic workup, absence from work, and time to convalescence were longest; and the number of diagnostic examinations was largest with radiography only. These outcomes were more favorable for both MRI strategies (EuroQol at 6 weeks 0.72 (95% CI 0.67-0.77) for both). Mean total costs were 2,593 euros (95% CI 1,815-3,372) with radiography only, 2,116 euros (95% CI 1,488-2,743) with radiography plus MRI, and 1,973 euros (95% CI 1,401-2,543) with selective MRI. The results suggest that selective use of a short MRI examination saves costs and potentially increases effectiveness in patients with acute knee injury without a fracture on radiography.

Is Magnetic Resonance Imaging Safe for Patients with Neurostimulation Systems Used for Deep Brain Stimulation?

n this article, we report to the neurosurgi-cal community important safety concernsrelated to the use of magnetic resonanceimaging (MRI) in patients with neurostimula-tion systems used for deep brain stimulation(DBS). The significance of these concerns isunderscored by our case report in this issueand another published recently (19). Thealarming report of a patient with a DBS im-plant experiencing adverse effects in associa-tion with an MRI examination emphasizes thecrucial importance of strictly following safetyrecommendations. Any attempt to generalizeor trivialize these safety aspects may result inserious temporary or permanent injury to thepatient.The DBS-Magnetic Resonance (DBS-MR)Safety Cooperative Group includes a consor-tium of experts in the fields of MR safety,biomedical engineering, radiology, and neu-rosurgery who have systematically studiedMRI safety for neurostimulation systems forthe past 4 years. In this issue, our group pre-sents a report of a patient who underwentMRI with adverse effects and report the latestfindings with respect to DBS and MRI safety.Of note is that the Food and Drug Adminis-tration recently issued a warning regardingthe use of MRI in patients with neurostimula-tion systems (23).The therapeutic use of electrical stimulationto treat neurological disorders is rapidlygrowing. There are more than 100,000 im-planted neurostimulation devices consistingof DBS, motor cortex stimulation, spinal cordstimulation, vagal nerve stimulation, and pe-ripheral nerve stimulation devices. The num-ber of patients with neurostimulation im-plants is increasing, clinical indications areevolving, and an increasing number of manu-facturers are providing Food and DrugAdministration-approved, or -pending, sys-tems.The focus of this Special Commentary is DBS.With more than 30,000 DBS implants world-wide and Food and Drug Administration-approved indications for treating Parkinson’sdisease, essential tremor, and dystonia, DBS isone of the most rapidly growing areas in thefield of neurosurgery (12, 20, 22). In addition, anumber of clinical trials are underway to assessthe role of DBS in treating epilepsy, chronicpain, cluster headaches, obsessive-compulsivedisorder, major depression, and other relatedconditions.Despite rapid growth in neurostimulationtechnologyandclinicalapplication,therehavebeen few studies directed at assessing thesafety of performing MRI procedures on pa-tients with DBS implants. The neurosurgery,neurology, and radiology communities havenot, for the most part, addressed the safetyfactors of DBS and MRI. The use of MRI pro-cedures for patients with DBS involves vari-ousapproaches. Certaincentersroutinely scanpatients with DBS devices based on thepremise that there have been no problems inthose scanned in the past. In other centers,MRI examinations of patients with DBS im-plants is strictly prohibited, as it is with pa-tients with cardiac pacemakers (1, 14–16).Other centers use various approaches and pol-icies in between.Importantly, the necessity of using MRI ex-aminations in these patients is implicit (3, 4,12, 13). MRI is important for the diagnosis ofhemorrhage, stroke, and other intracranial le-sions; for the assessment of the progression ofneurodegenerative disorders; and for the eval-uation of spinal disorders. In addition, MRI isbeneficial for determining postoperative DBSlead location, crucial for the evaluation of pa-tients with suboptimal results or side effects,