Contraindications For Magnetic Resonance Imaging Research Articles

MRI following scoliosis surgery? An analysis of implant heating, displacement, torque, and susceptibility artifacts

ObjectivesThe implant constructs used in scoliosis surgery are often long with a high screw density. Therefore, it is generally believed that magnetic resonance imaging (MRI) should not be carried out after scoliosis surgery, with the result that computed tomography is often preferred despite the ionizing radiation involved. The objective of this study was to evaluate the MRI compatibility of long pedicle-screw-rod constructs at 1.5 T and 3 T using standardized methods of the American Society for Testing and Materials (ASTM).MethodsConstructs between 130 and 430 mm long were systematically examined according to the ASTM standards F2182 (radio frequency–induced heating), F2119 (susceptibility artifacts), F2213 (magnetically induced torque), and F2052 (magnetically induced displacement force).ResultsThe maximum heating in the magnetic field was 1.3 K. Heating was significantly influenced by magnetic field strength (p < 0.001), implant length (p = 0.048), and presence of cross-links (p = 0.001). The maximum artifact width for different lengths of the anatomically bent titanium rods with CoCr alloy ranged between 14.77 ± 2.93 mm (TSE) and 17.49 ± 1.82 mm (GRE) for 1.5 T and between 23.67 ± 2.39 mm (TSE) and 27.77 ± 2.37 mm (GRE) for 3 T. TiCP and TiAl showed the smallest and CoCr and CoCr Plus the largest artifact widths. The magnetically induced torque and displacement force were negligible.ConclusionsMRI following scoliosis surgery with long implant constructs is safe with the patient in supine position. Although susceptibility artifacts can severely limit the diagnostic value, the examination of other regions is possible.Key Points• Large spinal implants are not necessarily a contraindication for MRI; MR conditional status can be examined according to the ASTM standards F2182, F2119, F2213, and F2052.• A metallic pedicle-screw-rod system could be reliably and safely examined in all combinations of length (130 to 430 mm), configuration, and material in a B0at 1.5 T and 3 T.• According to ASTM F2503, the examined pedicle-screw-rod system is MR conditional and especially the young patients can benefit from a non-ionizing radiation MRI examination.

Assessment of Brain Injury Using Portable, Low-Field Magnetic Resonance Imaging at the Bedside of Critically Ill Patients

Neuroimaging is a key step in the clinical evaluation of brain injury. Conventional magnetic resonance imaging (MRI) systems operate at high-strength magnetic fields (1.5-3 T) that require strict, access-controlled environments. Limited access to timely neuroimaging remains a key structural barrier to effectively monitor the occurrence and progression of neurological injury in intensive care settings. Recent advances in low-field MRI technology have allowed for the acquisition of clinically meaningful imaging outside of radiology suites and in the presence of ferromagnetic materials at the bedside. To perform an assessment of brain injury in critically ill patients in intensive care unit settings, using a portable, low-field MRI device at the bedside. This was a prospective, single-center cohort study of 50 patients admitted to the neuroscience or coronavirus disease 2019 (COVID-19) intensive care units at Yale New Haven Hospital in New Haven, Connecticut, from October 30, 2019, to May 20, 2020. Patients were eligible if they presented with neurological injury or alteration, no contraindications for conventional MRI, and a body habitus not exceeding the scanner's 30-cm vertical opening. Diagnosis of COVID-19 was determined by positive severe acute respiratory syndrome coronavirus 2 polymerase chain reaction nasopharyngeal swab result. Portable MRI in an intensive care unit room. Demographic, clinical, radiological, and treatment data were collected and analyzed. Brain imaging findings are described. Point-of-care MRI examinations were performed on 50 patients (16 women [32%]; mean [SD] age, 59 [12] years [range, 20-89 years]). Patients presented with ischemic stroke (n = 9), hemorrhagic stroke (n = 12), subarachnoid hemorrhage (n = 2), traumatic brain injury (n = 3), brain tumor (n = 4), and COVID-19 with altered mental status (n = 20). Examinations were acquired at a median of 5 (range, 0-37) days after intensive care unit admission. Diagnostic-grade T1-weighted, T2-weighted, T2 fluid-attenuated inversion recovery, and diffusion-weighted imaging sequences were obtained for 37, 48, 45, and 32 patients, respectively. Neuroimaging findings were detected in 29 of 30 patients who did not have COVID-19 (97%), and 8 of 20 patients with COVID-19 (40%) demonstrated abnormalities. There were no adverse events or complications during deployment of the portable MRI or scanning in an intensive care unit room. This single-center series of patients with critical illness in an intensive care setting demonstrated the feasibility of low-field, portable MRI. These findings demonstrate the potential role of portable MRI to obtain neuroimaging in complex clinical care settings.

THE APPLICATION OF LUNG MRI IN CASES OF COVID-19 INFECTION

A new coronavirus infection (COVID-19), which epidemic affected almost all states at the beginning of 2020, is also diagnosed radiologically, including computed tomography (CT), which is considered to be the gold standard for this. The lack of awareness among doctors and patients in a number of regions of Russia about the radiology use, need and appropriateness in this infection has led to unreasonable, overly frequent prescribing of chest CT by clinicians, as well as an increase in the chest CT ordering at the urgent request of the patients themselves, despite attempts of radiologists to convince those and others that, most often, this technique is not needed, as not affecting the observation and treatment strategy. The overload of CT units resulting from this has led to its limited availability, which, in addition, can also occur when CT devices get out of order. This publication is dedicated to our experience with magnetic resonance imaging (MRI) for the diagnosis of viral pneumonia. Changes detected on MRI are similar to those visible on CT, it is possible to detect a sign of «ground glass opacity», consolidations, reverse halo sign, fluid in the pleural cavity, air bronchography with an accuracy not less than that of CT, especially if the size of the pathological changes exceeds 1 cm. In addition, MRI allows the differential diagnosis of viral pneumonia and other clinical situations able to simulate it, such as a bron chogenic tumors with retro obstructive pneumonitis, exudative pleurisy, bacterial pneumonia, and bacterial infection inside the viral pneumonia. Given the inaccessibility of CT and/or radiation exposure conserns, MRI can serve as a fairly reliable alternative method for viral pneumonia and other pathological conditions with a nonspecific clinical picture radiological diagnosis and differential diagnosis, provided that anti-epidemic measures are observed and there are no absolute contraindications for MRI.

Joint Position Paper of the Working Group of Pacing and Electrophysiology of the French Society of Cardiology and the French Society of Diagnostic and Interventional Cardiac and Vascular Imaging on magnetic resonance imaging in patients with cardiac electronic implantable devices

Magnetic resonance imaging (MRI) has become the reference imaging technique for the management of a large number of diseases. The number of MRI examinations increases every year, simultaneously with the number of patients receiving a cardiac electronic implantable device (CEID). The presence of a CEID was considered an absolute contraindication for MRI for many years. The progressive replacement of conventional pacemakers and defibrillators by "magnetic resonance (MR)-conditional" CEIDs and recent data on the safety of MRI in patients with "MR-non-conditional" CEIDs have gradually increased the demand for MRI in patients with a CEID. However, some risks are associated with MRI in CEID carriers, even with MR-conditional devices, because these devices are not "MR safe". Specific programming of the device in "MR mode" and monitoring patients during MRI remain mandatory for all patients with a CEID. A standardized patient workflow based on an institutional protocol should be established in each institution performing such examinations. This joint position paper of the Working Group of Pacing and Electrophysiology of the French Society of Cardiology and the French Society of Diagnostic and Interventional Cardiac and Vascular Imaging describes the effect of and risks associated with MRI in CEID carriers. We propose recommendations for patient workflow and monitoring and CEID programming in MR-conditional, "MR-conditional non-guaranteed" and MR-non-conditional devices.

Burr hole drainage without irrigation for chronic subdural hematoma.

Background: Chronic subdural hematoma (CSDH) is one of the most common neurosurgical conditions, with different strategies for treatment. Most recent trials favor the use of drainage to reduce the recurrence rate. However, few reports have discussed the efficacy of burr hole drainage without irrigation for treating CSDH. This study aimed to examine the efficacy of burr hole drainage without irrigation in a series of 385 symptomatic CSDH lesions.Methods: This retrospective study included a series of 385 symptomatic CSDH lesions in 309 patients, who underwent burr hole drainage without irrigation, between September 2009 and August 2017 at the Department of Neurosurgery, Yao Tokushukai General Hospital, Japan. The risk of recurrence was evaluated based on the patients’ age, sex, preoperative magnetic resonance imaging (MRI) findings, preoperative anticoagulants, hematoma drainage rate, and bilaterality.Results: Of the 385 lesions, 41 cases (16 with inadequate follow-up periods and 25 with contraindications for MRI) were excluded from the analysis. The overall recurrence rate in the index study was 4.9% (17/344 lesions). The effects of the preoperative hematoma volume and nonhyperintensity on T1-weighted imaging on the recurrence rate were significant.Conclusion: Our findings indicated that burr hole drainage without irrigation is a good surgical modality in patients with CSDH, and preoperative MRI findings can evaluate the risk of recurrence.

Single-photon emission computed tomography/computed tomography arthrography of wrist, ankle, and knee joints.

To evaluate the additional value of single-photon emission computed tomography/computed tomography arthrography compared with single-photon emission computed tomography/computed tomography alone in wrist, ankle, and knee joints. Retrospective evaluation of 68 patients including 74 joints (48 wrists, 13 upper ankle (talocrural joint), and 13 knee joints) was performed. Activity in single-photon emission computed tomography/computed tomography images was graded using a four-point scale: 0 no uptake, one low uptake, two moderate uptake, and three high uptake. Arthrography images were evaluated for the presence of cartilage/ligament/meniscal lesions, and loose bodies. Fifty-six joints (76%) showed increased activity in late planar and 58 (78%) in single-photon emission computed tomography/computed tomography images, the latter graded as follows: grade 1 in 20 (34%), grade 2 in 29 (50%), grade 3 in nine (16%) joints. 16 joints were inactive (grade 0) in single-photon emission computed tomography/computed tomography. In 57 joints (77%), intraarticular contrast unmasked additional pathologies (37 cartilage lesions, 25 ligaments tears, 25 triangular fibrocartilage complex tears, six meniscal lesions, and four loose bodies). There was matching findings between single-photon emission computed tomography and computed tomography arthrography in 57 joints (77%) and mismatching findings in 17 joints (23%). Out of these 17 mismatched joints, eight were metabolically inactive but showed some lesion in computed tomography arthrography, whereas nine metabolically active joints did not show any abnormality in computed tomography arthrography. The addition of arthrography to single-photon emission computed tomography/computed tomography of wrist, ankle, and knee joints leads to supplementary visibility of lesions of cartilage, ligaments, triangular fibrocartilage complex, meniscus, or loose bodies in 77% of joints. Single-photon emission computed tomography/computed tomography arthrography can serve as promising alternative especially in patients with magnetic resonance imaging contraindications or metallic hardware.

Relationship of amyloid beta and neurofibrillary tau deposition in Neurodegeneration in Aging Down Syndrome (NiAD) study at baseline.

ImportanceAdults with Down syndrome (DS) are at high‐risk of revealing Alzheimer's disease (AD) pathology, in part due to the triplication of chromosome 21 encoding the amyloid precursor protein. Adults with DS are uniformly affected by AD pathology by their 30′s and have a 70% to 80% chance of clinical dementia by their 60′s. Our previous studies have assessed longitudinal changes in amyloid beta (Aβ) accumulation in DS.ObjectiveThe goal of the present study was to assess the presence of brain tau using [18F]AV‐1451 positron emission tomography (PET) in DS and to assess the relationship of brain tau pathology to Aβ using Pittsburgh Compound B (PiB)‐PET.DesignCohort studySettingMulti‐center studyParticipantsParticipants consisted of a sample of individuals with DS and sibling controls recruited from the community; exclusion criteria included contraindications for magnetic resonance imaging (MRI) and/or a medical or psychiatric condition that impaired cognitive functioning.ExposuresPET brain scans to assess Aβ ([11C]PiB) and tau ([18F]AV‐1451) burden.Main outcomes and measuresMultiple linear regression models (adjusted for chronological age, sex and performance site) were used to examine associations between regional [18F]AV‐1451 standard uptake value ratio (SUVR) (based on regions associated with Braak stages 1‐6) and global [11C]PiB SUVR (as both a continuous and dichotomous variable).ResultsA cohort of 156 participants (mean age = 39.05, SD(8.4)) were examined. These results revealed a significant relationship between in vivo Aβ and tau pathology in DS. As a dichotomous variable, [18F]AV‐1451 retention was higher in each Braak region in PiB(+) participants. We also found, based on our statistical models, starting with the Braak 3 region of interest (ROI), an acceleration of [18F]AV‐1451 SUVR deposition with [11C]PiB SUVR increases.

P610The microvascular obstruction and intramyocardial haemorrhage: impact of different reperfusion strategies in primary myocardial infarction

Abstract Background The coronary reperfusion in patients with ST-elevated myocardial infarction (STEMI) is often complicated by reperfusion-ischemic myocardial injury: microvascular obstruction (MVO) and intramyocardial haemorrhage (IMH). Contrast-enhanced cardiac magnetic resonance imaging (MRI) is the best diagnostic method, which allows to assess these phenomena. It is known that in patients with STEMI and primary percutaneous coronary intervention (PCI), the prevalence rates of MVO and IMH are 50–60% and 40–50%, respectively. There is not enough knowledge about the prevalence of these phenomena in patients with pharmaco-invasive strategy. Purpose The aim of the study was to evaluate the prevalence of MVO and IMH in patients with primary STEMI and different reperfusion strategies. Materials and methods This observational cohort study included 47 patients with primary STEMI within the first 12 hours after the onset of disease. Exclusion criteria: pulmonary edema, cardiogenic shock, creatinine clearance &lt;30 mL/min or dialysis, severe comorbidity, acute psychotic disorders, and inability to undergo or contra-indications for MRI. These patients were divided into 2 groups. Patients of group 1 (n=30) were treated with a pharmaco-invasive strategy. Fibrinolysis was performed in all patients in the pre-hospital setting. Patients of group 2 (n=17) were treated by primary PCI. MRI was performed at day 2 post-STEMI in all patients. Late gadolinium enhancement and T2-weighted IMH imaging for microvascular obstruction and IMH were used. Results Patients with primary PCI more often had MVO: 70.5% (n=12) vs. 40% (n=12) in the pharmaco-invasive group (p=0.05). The occurrence of IMH between the groups did not significantly differ: 40% (n=12) in group 1 vs. 64.7% (n=11) in group 2, respectively. The presence of combination of MVO with IMH was observed significantly more often in group of primary PCI: 47% (n=8) vs. 20% (n=6) (p=0.03). The left ventricular ejection fraction was significantly lower in patients with combination of IMH and MVO compared to those without it: 55% (34–66) vs. 62.5% (53–72) (p=0.01). Conclusion MVO and IMH were common findings in patients with primary STEMI and different reperfusion strategies and were present in 40% to 70% of patients. The MVO and combination of MVO with IMH occurred significantly more often in the group of primary PCI. The prevalence rates of IMH in patients with different reperfusion strategies did not significantly differ. ClinicalTrials.gov, identification number is NCT03677466.

Lesion-aphasia discordance in acute stroke among Bengali-speaking patients: Frequency, pattern, and effect on aphasia recovery

Abstract Introduction Contemporary research papers have highlighted the issue of lesion-aphasia discordance in reference to the classic ‘associationist’ model provided by Wernicke-Lichtheim. The objective of the present study is to explore frequency, pattern and evolution of lesion-discordant aphasia following first ever acute stroke in Bengali-speaking subjects. Methods Bengali version of Western Aphasia Battery, a validated scale, was used for language assessment in our study subjects. Lesion localization was done by using Magnetic resonance imaging (MRI) (3T) for ischemic stroke (if not contraindicated) and computed tomography (CT) for hemorrhagic stroke. Among 515 screened cases of first-ever acute stroke, 208 presented aphasia. Language assessment was done between 7 and 14 days in all study subjects and was repeated between 90 and 100 days in patients available for follow-up. Ischemic stroke cases with contraindication for MRI underwent CT imaging. Discordance between lesion and aphasic phenotype was determined only for right-handed subjects with cortical involvement (isolated or in combination with sub-cortical white matter) in the left hemisphere. Appropriate statistical tests were used to analyze the collected data. Results Lesion-aphasia discordance was found in 20 out of 134 patients with aphasia who were dextral and had cortical involvement in the left hemisphere (14.92%). The pattern of discordance observed were- posterior lesion with Broca's aphasia (4; 20%); posterior lesion with global aphasia (8; 40%); anterior lesion with global aphasia (4; 20%), and posterior lesion with mixed transcortical aphasia (4; 20%). On univariate analysis, the factors significantly associated with lesion-aphasia discordance were hemorrhagic stroke (p = 0.000); posterior perisylvian location (p = 0.002), and higher education (p = 0.048). After adjusting for all other variables, hemorrhagic stroke was found to have strong association with lesion-aphasia discordance (p = 0.001, OR = 11.764, 95% CI, 2.83–50.0). Discordant cases were more likely to recover or change to a milder type compared to concordant cases (p = 0.007, OR = 11.393, 95% CI, 1.960–66.231), after adjusting for all other variables including initial severity of aphasia (p = 0.006, OR = 8.388, 95% CI, 1.816–38.749). Conclusion Lesion-aphasia discordance following acute stroke is not uncommon among Bengali-speaking subjects. In the discordant group, preponderance towards non-fluent aphasia was observed. Discordance occurred more frequently after hemorrhagic stroke. Subjects with lesion-discordant aphasia presented better recovery during early post-stroke phase.

Diagnostic Accuracy and Validity of Magnetic Resonance Imaging in the Detection of Speci!c Type of Brain Tumour

Magnetic Resonance Imaging (MRI) is a widely accessible imaging technique for the detection of brain tumours and cancer, which are further confirmed by histopathological examination. Accurate detection of the tumours and its extent is very difficult. The present study attempted to evaluate the convenience of MRI in detection of different grades of astrocytomas, which are the most commonly occurring brain tumours. This cross-sectional study was conducted at the Department of Radiology and Imaging with the collaboration of Department of Neurosurgery and Department of Pathology at Sir Salimullah Medical College (SSMC &amp; MH), Dhaka from January 2013 to December 2013 for a period of one year. The study population was all the diagnosed cases of intracranial astrocytoma patients regardless of their age and sex. The studied included 48 brain tumour (astrocytoma) patients, ages between 13 and 69 years old. All cases having no contraindication for MRI underwent MR examination followed by histopathological examination of the postoperative resected tissues. The findings of the MRI and histopathological examination were compared to find out the test validity of the MRI findings of the different grades of astrocytoma’s. The highest sensitivity was found in grade III astrocytoma (90.5%) followed by grade II (85.7%) grade IV (75.0%) and grade I (60.0%). The highest specificity was found in grade I astrocytoma (97.7%) followed by Grade III (96.3%), grade IV (92.5%) and grade II (91.5%). The highest accuracy was found in both grade I astrocytoma (93.7%) and grade III (93.7%) followed by grade II (92.5%) and grade IV (89.6%). As per the study findings it can be concluded that,MRI has a high diagnostic accuracy and validity for the detection of different grades of astrocytoma.&#x0D; Bangladesh Med J. 2017 Sep; 46 (3): 85-89

Magnetic resonance imaging can diagnostic early morphofunctional changes in the myocardium in young people with type 1 diabetes

Aim. To study the morphofunctional state of the myocardium in young people with diabetes mellitus 1 using magnetic resonance imaging (MRI) technology. Materials and methods. 38 patients (14 men, 24 women), aged 18 to 36 years old, with an experience of type 1 diabetes from 5 to 16 years old were underwent contrastive MRI of the heart. The exclusion criteria were: pronounced electrolyte disorders in the blood, dysproteinemia, chronic liver and kidney failure - glomerular filtration rate (EPI)≤60 ml/min/1.73 m2, thyroid dysfunction, obesity (body mass index ≥30 kg/m2), diagnosed cardiovascular diseases, contraindications for MRI. The indicators of functional changes in the left ventricle (circular strain, strain relaxation index - SRI), peak early diastolic strain (PSRDS) were obtained and the accumulation of the contrast agent in the delayed period were assessed. Results. The obtained results of strain, SRI, PSRDS do not allow to exclude the presence of functional changes in the myocardium of the left ventricle. In 42.11%, zones of accumulation of the contrast agent were visualized in the delayed period (insignificant - 28.95% and moderate accumulation - 13.16%), mainly by the endocardium of the cardiac apparatus (mitral and tricuspid), and in one observation (2.9%) - in combination with unexpressed diffuse heterogeneity of the myocardium of the left ventricle. Conclusion. MRI of the heart is a promising direction in the assessment of early morphofunctional changes in the structure of the myocardium, which will probably make it possible to predict life-threatening changes in the heart muscle in young patients with type 1 diabetes.

Minimally Invasive Cervical Laminectomy for Cervical Spondylotic Myelopathy.

Cervical spondylotic myelopathy is a common cause of neurological disability, especially in aging populations. There are several approaches to decompress the cervical spinal cord, including anterior cervical discectomy and fusion, corpectomy and fusion, arthroplasty, posterior cervical laminectomy with or without fusion, and laminoplasty. Less well described is minimally invasive cervical laminectomy. The authors report their technique and results for minimally invasive cervical laminectomy. The authors describe in detail their surgical technique and results of 30 consecutive cases. Preoperative and postoperative modified Japanese Orthopaedic Association (mJOA) myelopathy scores were recorded. In total, 30 cases were included. Mean age was 69 years (range, 57-89 y). Twelve procedures were at C3-4, 4 at C4-5, 5 at C5-6, 4 at C7-T1, 3 at C3-4 and C4-5, 1 at C4-5 and C5-6, and 1 at C5-6 and C6-7. Mean preoperative mJOA score was 12.1 (range, 4-15). Average length of surgery was 142 minutes. Mean follow-up was 27 months (range, 3-64 mo). At 3 months, mean postoperative mJOA score was 14.0 (range, 5-17). Mean mJOA improvement of 1.9 was statistically significant (P<0.001). Seventeen patients had magnetic resonance imaging (MRI) available at 3 months postoperatively (5 patients had no MRI, 3 patients had MRI contraindications, and 5 are pending). No MRI findings led to further surgery. There were no durotomies and no wound infections. A single patient had an unexplained new neurological deficit that resolved over 6 months. Minimally invasive laminectomy for cervical myelopathy is safe and effective and may be an underutilized procedure.

Novel extraction technique of retained pacemaker and defibrillator lead during heart transplantation

BackgroundRemoval of cardiac implantable electronic devices (CIEDs) by manual traction during orthotopic heart transplantation (OHT) sometimes results in retained lead fragments. Moreover, abandoned leads and retained lead fragments are a contraindication for magnetic resonance imaging (MRI) and may be a cause of CIED infection.ObjectiveTo eliminate complications of retained lead fragments, we completely removed residual leads using an excimer laser sheath technique during OHT. We report our clinical experience and high success rate of lead extraction using the excimer laser sheath compared with manual traction during OHT.Methods and resultsWe obtained data on 84 consecutive patients receiving OHT between August 2007 and August 2017. Thirty-nine of 84 patients had undergone CIED implantation before OHT and removal of all their leads was attempted during OHT. From 2007 to 2014, defibrillator and pacemaker leads were extracted by manual traction in all patients (N = 22). After 2015, all leads were extracted with the excimer laser sheath, and surgical assistance was prepared for the procedure (N = 17). Complete procedural success was achieved in 100% of patients in the excimer laser group and 77% of patients in the manual traction group.ConclusionExtraction of abandoned leads using the excimer laser sheath system during OHT is novel and safe technique, and has a higher success rate than extraction using manual traction during OHT.

MP2RAGE and Susceptibility-Weighted Imaging in Lesional Epilepsy at 7T.

Surgery is the first choice therapeutic approach in case of drug-resistant epilepsy. Unfortunately, up to 43% of patients referred for presurgical assessment do not have a lesion detectable by routine 3T magnetic resonance imaging (MRI) (MRI-negative), although most of them likely have an underlying epileptogenic lesion. Thus, new MRI modalities with increased sensibility for epileptogenic lesions are required. This paper describes the magnetization-prepared two rapid acquisition gradient echoes (MP2RAGE) and susceptibility-weighted imaging (SWI) findings at 7T in a series of patients with drug-resistant epilepsy of different etiologies. Prospective pilot study of 7 patients with drug-resistant lesional epilepsy and absence of contraindications for MRI underwent a research 7T head-only scanner. Qualitative analysis of the high-resolution MP2RAGE and SWI sequences is given for each case. This study was approved by the local ethics committee. Written informed consent was obtained from each participant. This study shows that such sequences at ultra-high field are new and valuable approaches to unravel and characterize epileptogenic lesions. Particularly, MP2RAGE shows a better delineation of lesions due to high gray-white matter contrast and structural resolution, and SWI reveals new imaging signs related to improved magnitude and phase contrast imaging. MRI at ultra-high field is very promising for the detection of inconspicuous epileptogenic lesions and may facilitate epilepsy surgery of a great number of to-date MRI-negative patients.

Contrast-enhanced cone-beam breast-CT (CBBCT): clinical performance compared to mammography and MRI

To evaluate the diagnostic accuracy of contrast-enhanced (CE) cone-beam breast computed tomography (CBBCT) in dense breast tissue and compare it to non-contrast (NC) CBBCT, mammography (MG) and magnetic resonance imaging (MRI). This prospective institutional review board-approved study included 41 women (52 breasts) with American College of Radiology (ACR) density types c or d and Breast Imaging Reporting and Data System (BI-RADS) 4 or 5 assessments in MG or ultrasound (US). Imaging modalities were independently evaluated by two blinded readers. A total of 100 lesions (51 malignant, 6 high-risk, and 43 benign) were identified. For readers 1/2, respectively, and p values comparing CE-CBBCT to other modalities: diagnostic accuracy (AUC) for CE-CBBCT was 0.83/0.77, for MRI 0.88/0.89 (p = 0.2272/0.002), for NC-CBBCT 0.73/0.66 (p = 0.038/ 0.0186) and for MG 0.69/0.64 (p = 0.081/0.0207). CE-CBBCT sensitivity (0.88/0.78) was 37-39% higher in comparison to MG (0.49/0.41, p < 0.001 both) but inferior to MRI (0.98/0.96, p = 0.0253/0.0027). CE-CBBCT specificity (0.71/0.71) was numerically higher compared to MRI (0.61/0.69, p = 0.0956/0.7389). CBBCT diagnostic performance varied with the respective reader and experience. CE-CBBCT improved AUC and sensitivity in comparison to MG and NC-CBBCT, and was comparable to MRI in dense breast tissue. In tendency, specificity was higher for CE-CBBCT than MRI. • CE-CBBCT diagnostic accuracy (AUC) was comparable to MRI in dense breasts. • CE-CBBCT improved sensitivity and AUC in comparison to MG and NC-CBBCT. • CE-CBBCT has inferior sensitivity but higher specificity than MRI. • CE-CBBCT is a potential imaging alternative for patients with MRI contraindications.

Diagnosing Meniscal Pathology and Understanding How to Evaluate a Postoperative Meniscus Based on the Operative Procedure.

Magnetic resonance imaging (MRI) represents the preferred noninvasive imaging technique to diagnose meniscal pathology in the pre- and postoperative setting. Furthermore, characterization of meniscal tissue MR properties has been possible by the development of advanced MRI techniques. Suspected meniscal tears are a frequent indication for MRI and the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) classification system has been developed to facilitate accurate and uniform reporting of such meniscal tears. Partial meniscectomy and meniscal suture repair are among the commonly performed procedures and several signs have been described to detect postoperative recurrent tears on MRI. Other techniques that have proven useful for meniscal assessment are ultrasound (US) and computed tomography (CT) arthrography. In recent years, US is being increasingly used in the selective assessment of some meniscal pathology such as tears, parameniscal cysts and meniscal extrusion as it is a relatively inexpensive, accessible, and safe technique. CT arthrography has been advocated as an acceptable alternative in patients with contraindications for MRI, with comparable diagnostic performance.

Lumbar Disc Herniation, the Association Between Quantitative Sensorial Test and Magnetic Resonance Imaging Findings.

Quantitative sensorial tests (QST) are used for evaluating specific sensorial nerve function. In this study, QST and magnetic resonance imaging (MRI) findings are compared in lumbar disc herniation patients, and the accuracy of QST data was investigated. Sixty-four patients between 18 and 70 years of age suffering from radicular pain with positive Lasegue's test were included in this study. Specific criteria included complaints due to L5 discopathy. MRI findings were classified according to the Pfirmann grading system, and QST was applied to the L5 dermatoma of both symptomatic and nonsymptomatic legs of all patients. Vibration detection threshold, heat detection threshold, cold detection threshold, and heat pain detection threshold values were obtained, and MRI findings were classified according to the Pfirmann grading system. When we compared the symptomatic and nonsymptomatic legs of participants, there were significant differences by means of all QST parameters (0 = 0.00). In a comparison of the QST and MRI Pfirmann grading systems, there is also a strong parallel statistical correlation between the Pfirmann grade and QST parameters (P < 0.05). According to the results of our study, QST has an additive effect to MRI for nerve root compression evaluation in the clinical basis, which might enable more sensitive diagnosis and treatment protocol. QST can also be an alternative method for evaluation of nerve root compression in patients who have contraindications for MRI.

Contrast-enhanced spectral mammography in patients with MRI contraindications.

Background Contrast-enhanced spectral mammography (CESM) is a novel breast imaging technique providing comparable diagnostic accuracy to breast magnetic resonance imaging (MRI). Purpose To show that CESM in patients with MRI contraindications is feasible, accurate, and useful as a problem-solving tool, and to highlight its limitations. Material and Methods A total of 118 patients with MRI contraindications were examined by CESM. Histology was obtained in 94 lesions and used as gold standard for diagnostic accuracy calculations. Imaging data were reviewed retrospectively for feasibility, accuracy, and technical problems. The diagnostic yield of CESM as a problem-solving tool and for therapy response evaluation was reviewed separately. Results CESM was more accurate than mammography (MG) for lesion categorization (r = 0.731, P < 0.0001 vs. r = 0.279, P = 0.006) and for lesion size estimation (r = 0.738 vs. r = 0.689, P < 0.0001). Negative predictive value of CESM was significantly higher than of MG (85.71% vs. 30.77%, P < 0.0001). When used for problem-solving, CESM changed patient management in 2/8 (25%) cases. Superposition artifacts and timing problems affected diagnostic utility in 3/118 (2.5%) patients. Conclusion CESM is a feasible and accurate alternative for patients with MRI contraindications, but it is necessary to be aware of the method's technical limitations.

Magnetic resonance imaging in patients with cardiac implantable electronic devices: a single-center prospective study.

Cardiac implantable electronic devices (CIEDs) have traditionally been a contraindication for magnetic resonance imaging (MRI). Recent studies suggest that MRI can be conducted safely in select patients with pacemakers (PPMs) and implantable cardioverter defibrillators (ICDs). We sought to determine the safety of MRI in patients with CIEDs, using a protocol for patient selection and device programming. This is a prospective, single-center study. Patients with a PPM or ICD and a clinical indication for MRI were considered. Exclusion criteria included newly implanted devices (<4weeks), PPMs manufactured before 1996 and ICDs before 2000, epicardial and abandoned leads, and pacemaker-dependent ICD patients. Pacemaker-dependent PPM patients were programmed to asynchronous pacing. Tachycardia detection/therapies were disabled for ICDs. Devices were interrogated pre- and post-scan, and at follow-up 1-6weeks later. Defibrillation threshold (DFT) was not tested post-scan. Patients were followed to monitor device therapies. Two hundred twenty-seven patients underwent 293 scans. Devices included 170 (70.6%) PPMs and 71 (29.5%) ICDs. Thirteen (4.4%) scans were aborted mainly due to subjective complaints or artifact on scout cardiac imaging. Post-scan and follow-up interrogation demonstrated no changes in device parameters requiring reprogramming or revision. Over long-term follow-up (median, 354days [IQR 65-629]), nine ICD patients had appropriate shocks (median, 3 [IQR 1-8]). One had four inappropriate shocks for atrial fibrillation. All tachyarrhythmias meeting criteria for defibrillation were successfully terminated. MRI can be conducted safely in patients with CIEDs when done in a protocoled manner with appropriate supervision. DFT testing after MRI may not be necessary.

Interventional therapies in stroke management: anaesthetic and critical care implications

### Key points Recent advances in stroke therapy have necessitated new multidisciplinary care pathways. This article will cover interventions used in acute stroke management, including the role of imaging, thrombolysis, interventional radiology, arterial pressure (AP) management, carotid revascularization, haematoma evacuation, and decompressive hemicraniectomy (DHC). The anaesthetic and critical care implications of these interventions are described. Computed tomography (CT) scanners have increased from a single-slice detector to advanced 320-slice scanners capable of performing whole-head imaging in a single rotation. This allows multiple acquisitions during a single contrast injection such that non-contrast CT, angiogram, subtraction cerebral angiography, and perfusion imaging can be performed in a single sitting. With CT perfusion scans, the size of the infarcted core can be seen and also the hypoperfused area around it (the penumbra) which represents brain tissue that may be salvaged if blood flow is restored with reperfusion therapies. Similar advances have been made with magnetic resonance imaging (MRI). MRI with diffusion-weighted imaging (DWI) can differentiate between recent infarction, intracranial masses, and inflammatory disease, and is more sensitive than CT for the detection of acute infarction. It does however have disadvantages in that acutely ill patients may not tolerate it as well and some may even have contra-indications for MRI. Furthermore, MRI may not be readily available in the emergency setting, the acquisition time is longer and MRI is more expensive than CT. Since the primary aim of imaging in acute stroke is to exclude intracranial haemorrhage (which CT is very well suited for), …