Gadolinium- and superparamagnetic-iron-oxide-enhanced MR findings of intrapancreatic accessory spleen in five patients

Purpose

The purposes of this study were to describe dynamic gadolinium-enhanced magnetic resonance imaging (MRI) findings of intrapancreatic accessory spleen(s) (IPAS) in five patients and to show how superparamagnetic iron oxide (SPIO) enhancement can be used for definite characterization in two cases.

Materials and Methods

An MRI database was searched for patients who had pancreatic tail lesions with imaging features compatible with IPAS between June 2005 and July 2007. Five (four male, one female) patients (age: mean±S.D., 58±9.8 years; range, 50–75 years) were identified. All patients were examined with standard gadolinium-enhanced MRI protocol. Additionally, two patients were examined with SPIO-enhanced MRI protocol. All MRI examinations were retrospectively and blindly evaluated by two radiologists for the predetermined findings, and their final diagnoses were noted.

Results

One pancreatic tail lesion was detected in each patient. All of these lesions were single, focal, well-marginated and located within 3 cm of the distal tail of the pancreas. The mean size (mean±S.D.) of the lesions was (2.02±0.64)×(1.72±0.42) cm², and all lesions had a rounded morphology. The signal intensity of all lesions was similar to that of the spleen on all sequences, including precontrast, postgadolinium and post-SPIO sequences. The reviewers confidently diagnosed IPAS in two patients who had SPIO-enhanced MRI. In the remaining three patients, the reviewers favored the diagnosis of IPAS based on the findings of standard gadolinium-enhanced MRI; however, they could not definitively exclude the other differential diagnoses.

Conclusion

The discovery of a well-marginated, rounded mass in the distal aspect of the tail of the pancreas with signal intensity features of the spleen on all precontrast and postgadolinium sequences suggests the diagnosis of IPAS. However, SPIO-enhanced MRI can be used to characterize the lesion and to establish the definite diagnosis of IPAS in case of clinical doubt.     

7 T μMRI of mesenteric venous ischemia in a rat model: Timing of the appearance of findings

Objectives

The aim of this study is to analyze the chronological development of macroscopic, microscopic and magnetic resonance imaging (MRI) findings in a rat model of Superior Mesenteric Venous (SMV) ligation, and to evaluate the role of MRI in the diagnosis of mesenteric venous thrombosis.

Methods

Thirty adult Sprague–Dawley rats were used and divided in two different groups that underwent a different surgical model and a different monitoring of ischemic damage. Group I underwent macroscopical and histological observation; Group II underwent 7 T μMRI evaluation and histological analysis.

Results

The first alterations occurred 30 min after SMV ligation and progressively worsened until the eighth hour. The morphological and MRI findings showed the same course.

Conclusions

This study provides a systematic evaluation of early anatomopathological and MRI findings following the SMV ligation. MRI allows to identify the early pathological findings of venous mesenteric ischemia and allows to correlate those to the histopathological features. Our data suggest a relevant role of MRI in the diagnostic management of mesenteric venous thrombosis, allowing to non-invasively identify and characterize the histopathologic findings. So, thanks to these skills, its future application in early diagnosis of human mesenteric venous ischemia is supposable.     

MRI findings in nonalcoholic steatohepatitis: correlation with histopathology and clinical staging

Purpose

To evaluate magnetic resonance imaging (MRI) findings of nonalcoholic steatohepatitis (NASH) and to determine the correlation of MRI findings with histopathology and Mayo End-Stage Liver Disease (MELD) score.

Materials and Methods

Thirty patients (18 males, 12 females; mean age: 57±8.9 years; age range: 35–71 years) with histopathologically proven NASH who underwent MRI examinations between January 2001 and October 2005 were included in the study. Two radiologists retrospectively reviewed all magnetic resonance (MR) examinations in consensus to evaluate the presence and extent of predetermined findings of NASH including liver steatosis, early patchy liver enhancement indicating inflammation and liver fibrosis. The findings detected on MRI were correlated and compared to histopathological findings and MELD score by using nonparametric Spearman correlation coefficient and Kruskal–Wallis analysis of variance.

Results

Liver steatosis was observed in 10 of 30 patients; early patchy liver enhancement, in 8 of 30 patients and liver fibrosis in 19 of 30 patients on MR images. Liver fibrosis was reticular in all these patients. There were statistically significant moderate correlations between MRI findings of liver steatosis and histopathologic grades of steatosis (r=0.43; P<.05), and between MRI findings of fibrosis and histopathologic stages of fibrosis (r=0.61; P<.001). Early patchy enhancement did not demonstrate statistically significant correlation with inflammation (P=.28). There was no statistically significant overall correlation between MRI findings of NASH and MELD score.

Conclusion

MRI findings of liver steatosis and fibrosis in NASH showed moderate correlations with histopathologic grades of steatosis and stages of fibrosis, but MRI findings of NASH did not demonstrate any significant correlations with MELD score.     

Diagnosis of relevant prostate cancer using supplementary cores from magnetic resonance imaging-prompted areas following multiple failed biopsies

Objectives

To establish the value of MRI in targeting re-biopsy for undiagnosed prostate cancer despite multiple negative biopsies and determine clinical relevance of detected tumors.

Materials and Methods

Thirty-eight patients who underwent MRI after 2 or more negative biopsies due to continued clinical suspicion and later underwent TRUS-guided biopsy supplemented by biopsy of suspicious areas depicted by MRI were identified. Diagnostic performance of endorectal 3T MRI in diagnosing missed cancer foci was assessed using biopsy results as the standard of reference. Ratio of positive biopsies using systematic versus MRI-prompted approaches was compared. Gleason scores of detected cancers were used as surrogate for clinical relevance.

Results

Thirty-four percent of patients who underwent MRI before re-biopsy had prostate cancer on subsequent biopsy. The positive biopsy yield with systematic sampling was 23% versus 92% with MRI-prompted biopsies(p < 0.0001). Seventy-seven percent of tumors were detected exclusively in the MRI-prompted zones. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of MRI to provide a positive biopsy were 92%, 60%, 55%, 94% and 71%, respectively. The anterior gland and apical regions contained most tumors; 75% of cancers detected by MRI-prompted biopsy had Gleason score ≥ 7.

Conclusions

Clinically relevant tumors missed by multiple TRUS-guided biopsies can be detected by a MRI-prompted approach.     

Determining uterine blood flow in pregnancy with magnetic resonance imaging

Objective

The purpose of this study is to determine the feasibility of measuring total uterine blood flow in pregnancy using magnetic resonance imaging (MRI) technique.

Methods

Uterine blood flow was determined in pregnant women in whom MRI was being carried out to assess a fetal anomaly. A two-dimensional time-of-flight magnetic resonance (MR) angiogram sequence was performed. Scout images and a peripherally gated phase contrast MR sequence were planned to study simultaneous blood flow in the uterine and ovarian arteries.

Results

The MR pelvic angiogram sequence was completed in 13 women. The uterine arteries were visualized and their cross-sectional area determined. The complexity of the pelvic blood supply prevented the calculation of blood flow velocity and, thus, total uterine blood flow.

Conclusion

The measurement of total uterine blood flow during pregnancy was not possible using our MR technique. The ovarian vessels were not consistently visualized. Doppler ultrasonography remains the best modality by which to estimate total uterine blood flow in pregnancy.     

Characterization of cryoinjury-induced infarction with manganese-and gadolinium-enhanced MRI and optical spectroscopy in pig hearts

Purpose

To investigate progression of cryoinjury in pigs using contrast-enhanced magnetic resonance imaging (MRI) as well as optical spectroscopy and imaging.

Methods

Cryoinjury was produced in 16 pigs in vivo and investigated using Gd-and Mn-enhanced MRI, optical imaging/spectroscopy and histology in acute and chronic setting up to 4 weeks after the injury.

Results

(1) Acute cryoinjury resulted in formation of a lesion with a severely reduced rate of sub-epicardial indocyanine green (intravascular optical flow tracer) passage. In vivo late Gd-enhanced MRI showed a ∼10 mm deep hypointense area that was surrounded by a hyperintense rim while ex vivo Mn-enhanced MRI (MEMRI) detected a homogenous hypointense zone. Histological and spectroscopic examination revealed embolic erythrocytes blockages within the cryolesion with a thin necrotic rim neighboring the normal myocardium. (2) Chronic 4-week cryoinjury was characterized by uniform Gd-enhancement, whereas MEMRI revealed reduced Mn²⁺enhancement. Histological examination showed replacement of the cryoinjured myocardium by scar tissue.

Conclusions

Acute cryoinjury resulted in formation of a no-reflow core embolized by erythrocytes and surrounded by a rim of necrotic tissue. Upon injury progression, the no-reflow zone shrunk and was completely replaced with scar tissue by 4 weeks after injury.     

MR evaluation of breast lesions obtained by diffusion-weighted imaging with background body signal suppression (DWIBS) and correlations with histological findings

Objectives

Diffusion imaging represents a new imaging tool for the diagnosis of breast cancer. This study aims to investigate the role of diffusion-weighted MRI with background body signal suppression (DWIBS) for evaluating breast lesions.

Methods

90 patients were prospectively evaluated by MRI with STIR, TSE-T2, contrast enhanced THRIVE-T1 and DWIBS sequences. DWIBS were analyzed searching for the presence of breast lesions and calculating the ADC value. ADC values of ≤ 1.44 × 10^- 3 mm²/s were considered suspicious for malignancy. This analysis was then compared with the histological findings. Sensitivity, specificity, diagnostic accuracy (DA), positive predictive value (PPV) and negative (NPV) were calculated.

Results

In 53/90 (59%) patients, DWIBS indicated the presence of breast lesions, 16 (30%) with ADC values of  > 1.44 and 37 (70%) with ADC ≤ 1.44. The comparison with histology showed 25 malignant and 28 benign lesions. DWIBS sequences obtained sensitivity, specificity, DA, PPV and NPV values of 100, 82, 87, 68 and 100%, respectively.

Conclusion

DWIBS can be proposed in the MRI breast protocol representing an accurate diagnostic complement.     

Beyond laparoscopy: 3-T magnetic resonance imaging in the evaluation of posterior cul-de-sac obliteration

Objectives

Endometriosis is the ectopic localization of endometrial glands. Symptoms include a wide variety of chronic pelvic pain. Ovarian endometriosis represents the most frequent site of implantation followed by the Douglas pouch which is undepicted unless peritoneal fluid is present. Pelvic exams may be reported as normal in 40% of evaluations, although multiple nodularities are located in this region. Nowadays, laparoscopy represents the standard technique for endometriosis evaluation. However, magnetic resonance imaging (MRI) remains the best noninvasive technique for the evaluation of pelvic lesions. According to the importance of a precise preoperative diagnosis of deep infiltrative endometriosis involving the Douglas pouch, we evaluated feasibility of a 3-T system in the evaluation of this particular region.

Methods

We enrolled 19 women coming with either ultrasound or anamnestic suspicion of endometriosis. Pelvic MRI examination was performed on the 3-T system. We applied a standard exam protocol including pulse sequences [single-shot fast spin echo (FSE)] and high-resolution T2W and T1W FSE sequences with and without FS.

Results

MRI diagnosed posterior cul-de-sac obliteration in 15/19 patients. MRI findings were compared with laparoscopy, thus obtaining the following statistical values: mean sensitivity, specificity, positive predictive value and negative predictive value, respectively, of 93%, 75%, 93% and 75%. Moreover, we calculated an interobserver agreement k value of 0.72 with a substantial degree of agreement between two radiologists of a sensitivity value of 93% and specificity value of 75%.

Conclusions

Precise preoperative mapping of posterior cul-de-sac region is essential for a preoperative planning. In our work, the 3-T MRI was shown to be excellent in the evaluation of posterior cul-de-sac obliteration associated to an optimal evaluation of the uterosacral ligaments due to the higher contrast spatial resolution.     

Guided e-MRI prostate biopsy can solve the discordance between Gleason score biopsy and radical prostatectomy pathology

Introduction

The aim of this study is to examine if guided prostate biopsies based on abnormalities detected by conventional and functional endorectal magnetic resonance imaging (MRI) yield a more reliable representation of the radical prostatectomy pathology and to identify probable preoperative clinical variables that stratified patients likely to harbor significant upgrading.

Patients and Methods

From April 2004 to April 2009, a review of N=70 patients records diagnosed with prostate cancer by a 3-6 core guided transrectal ultrasound (TRUS) prostate biopsy based on abnormalities detected by conventional and functional endorectal MRI and who subsequently underwent radical prostatectomy and exhibited a significant upgrading was conducted. Additionally, a multivariate analysis with a significant upgrading as the outcome was performed including the following parameters: prostate specific antigen (PSA) level, clinical stage, prostate size and duration from biopsy to radical prostatectomy.

Results

A significant upgrading was noted in only 8.5% of patients, with 1.4% exhibiting a significant downgrading and the rest 90.1% exhibiting an exact Gleason score match. No preoperative clinical variables that stratified patients likely to harbour significant upgrading were identified.

Conclusions

This type of biopsy method seems to solve the discordance between the biopsy Gleason score and radical prostatectomy pathology regardless of known preoperative clinical variables that can affect it.     

Assessment of MRI issues for the Argus II retinal prosthesis

Objective

The objective was to evaluate magnetic resonance imaging (MRI) issues (magnetic field interactions, heating, artifacts and functional alterations) at 1.5 T and 3 T for the Argus II Retinal Prosthesis (Second Sight Medical Products, Sylmar, CA, USA).

Materials and Methods

Standardized protocols were used to assess magnetic field interactions (translational attraction and torque; 3 T, worst case), MRI-related heating (1.5 and 3 T), artifacts (3 T; worst case) and functional changes (1.5 and 3 T) associated with MRI.

Results

The magnetic field interactions were acceptable. MRI-related heating, which was studied at a relatively high, MR system-reported whole body averaged specific absorption rates, will not pose a hazard to the patient under the conditions used for testing. While artifacts were “moderate” in relation to the dimensions of the Argus II Retinal Prosthesis, optimization of MRI parameters can reduce the size of the artifacts. Exposures to MRI conditions at 1.5 and 3 T did not damage or alter the functional aspects of the Argus II Retinal Prosthesis.

Conclusions

In consideration of the test results, a patient with the Argus II Retinal Prosthesis may undergo MRI at 1.5 T or 3 T when specific guidelines and MRI conditions are followed, including those advised by the manufacturer.     

3D high-resolution contrast enhanced MRI of carotid atheroma — a technical update

Objective

Development of a fast 3D high-resolution magnetic resonance imaging (MRI) protocol for improved carotid artery plaque imaging.

Methods

Two patients with carotid atherosclerosis disease underwent 3D high-resolution MRI which included time-of-flight and T₁-weighted variable flip angle, fast-spin-echo (FSE) imaging, pre- and post-intravenous gadolinium-based contrast agent administration.

Results

Good quality images with intrinsic blood suppression were obtained pre- and post-contrast administration using a 3D FSE sequence. The plaque burden, lipid core volume, hemorrhage volume and fibrous cap thickness were well determined.

Conclusions

3D high-resolution MR imaging of carotid plaque using TOF and 3D FSE can achieve high isotropic resolution, large coverage, and excellent image quality within a short acquisition time.     

Occipital lobe's cortical thinning in ametropic amblyopia

Background and Purpose

The present study was designed to detect the abnormalities of the cortical thickness in children with ametropic amblyopia by a computer-aided MRI technique.

Methods

Nine children with ametropic amblyopia and eight age-matched normal controls underwent MRI brain scanning that was performed on a Siemens Avanto 1.5-T scanner, and standard T₁-weighted high-resolution anatomic scans of magnetization-prepared rapid gradient echo (MPRAGE) sequence were obtained. For the cortical thickness analysis, 3D MPRAGE images were processed with FreeSurfer software package (http://www.nmr.mgh.harvard.edu/freesurfer/), and the cortical thicknesses were compared between the patient group and the normal control group.

Results

The cortical thicknesses of the lingual and pericalcarine areas in the left hemisphere and of the cuneus, lateraloccipital and lingual areas in the right hemisphere in the amblyopic group were significantly thinner than those of the control group (P<.05).

Conclusion

The changes in cortical thickness of several occipital regions in amblyopic patients may be important in the diagnosis and treatment of this disease.     

Evaluation of MRI artifacts at 3 Tesla for 38 commonly used cosmetics

Purpose

To evaluate MRI artifacts at 3-Tesla for 38 commonly used cosmetics.

Materials and Methods

Thirty-eight cosmetics (16, nail polishes; 5, eyeliners; 3, mascaras; 10, eye shadows; 1, lip gloss; 1, body lotion; 1, body glitter, and 1, hair loss concealer) underwent evaluation for MRI artifacts at 3-Tesla. The cosmetics were applied a copper-sulfate-filled, phantom and initially assessed using a “screening” gradient echo (GRE) pulse sequence. Of the 38 different cosmetics, 14 (37%) exhibited artifacts. For these 14 cosmetics, additional characterization of artifacts was performed using a GRE pulse sequence. A qualitative scale was applied to characterize the artifact size.

Results

Artifacts were observed, as follows: 2, nail polishes; 5, eyeliners; 3, mascaras; 3, eye shadows; 1, hair loss concealer. Artifact size ranged from small (eye shadow) to very large (hair loss concealer) and tended to be associated with the presence of iron oxide or other metal-based ingredient.

Conclusions

Commonly used cosmetics caused artifacts that may create issues if the area of interest is the same as where the cosmetic was applied or if its presence was unknown, thus, potentially causing it to be construed as pathology. Therefore, these findings have important implications for patients referred for MRI examinations.     

Comparison between multi-echo T2* with and without fat saturation pulse for quantification of liver iron overload

Purpose

To test a magnetic resonance image (MRI) technique that uses an additional pulse in multi-echo T2* sequence that works to suppress the fat signal, in subjects with liver iron overload and concomitant presence of fat in the liver, which have been revealed as a major drawback that compromises the correct iron quantification by MRI.

Materials and Methods

Fifty magnetic resonance images of the liver (1.5 T scanner) of individuals with blood ferritin increases were retrospectively reviewed for the presence of steatosis, using the sequence in and out of phase, and iron overloading, using two sequences T2 * multi-echo: one standard and other with additional fat suppression pulse. T2 * values and their standard deviations were analyzed statistically.

Results

Our results showed that a significantly lower standard deviation of T2* values is obtained when the fat saturation pulse is applied in patients with steatosis. We found that modulation of fat signal on liver iron overload resulted in a different categorization of some patients. In one case, the patient was re-classified within normal levels of liver iron.

Conclusion

Our findings may contribute to a better measure of liver iron overload with relevant implications for patient treatment and care.     

Artifacts in magnetic resonance imaging after surgical resection of brain tumors

Background

Since the advent of magnetic resonance imaging, metal artifacts have posed an important diagnostic problem in different fields of medicine. However, this has not been systematically studied in patients undergoing surgery for brain tumors.

Objective

This study was planned to assess whether metal artifacts can occur in patients undergoing brain surgery without metallic implants.

Methods

Of 40 individuals who could be included because of having a pre- and postoperative MRI and a postoperative computed tomography (CT) scan or a conventional skull X-ray for the detection of metallic artifacts, 26 patients agreed to participate in this study and gave informed consent.

Results

Twenty-six subjects, 12 males and 14 females, with an age range of 12 to 54 years, were included in the study. Four patients were found to have gross metal particles in their postoperative brain CTs and were excluded. Of the remaining 22 subjects, 7 patients (31.8%) had metallic artifacts.

Conclusion

Our study showed that simple bone drilling or chiseling during surgical manipulation of skull bones may result in separation of very tiny metal particles which can remain in the surgical site and cause artifacts in postoperative MRIs. This finding appeared to be independent of factors such as age, sex, tumor/incision site, tumor size, pathologic tumor type, total radiation dose, operation–MRI time interval and sequence of MRI.     

Assessment of normal flow patterns in the pulmonary circulation by using 4D magnetic resonance velocity mapping

Objective

The purpose of this study was to analyze flow patterns in the pulmonary circulation of healthy volunteers by using 4D flow magnetic resonance imaging.

Materials and Methods

The study was approved by the local ethics committee and all subjects gave written informed consent. Eighteen volunteers underwent a 4D flow scan of the whole-heart. Two patients with congenital heart disease were also included to detect possible patterns of flow abnormalities (Patient 1: corrected transposition of great arteries (TGA); Patient 2: partial anomalous pulmonary venous return and atrial septal defect). To analyze flow patterns, 2D planes were placed on the main pulmonary artery (PA), left and right PA. Flow patterns were assessed manually by two independent viewers using vector fields, streamlines and particle traces, and semi-automatically by vorticity quantification.

Results

Two counter-rotating helices were found in the main PA of volunteers. Right-handed helical flow was detected in the right PA of 15 volunteers. Analysis of the helical flow by particles traces revealed that both helices contributed mainly to the flow in the right PA. In the patient with corrected TGA helical flow was not detected. Abnormal vortical flow was visualized in the main PA of patient 2, suggesting elevated mean PA pressure.

Conclusions

Helical flow is normally present in the main PA and right PA. 4D flow is an excellent tool to evaluate noninvasively complex blood flow patterns in the pulmonary circulation. Knowledge of normal and abnormal flow patterns might help to evaluate patients with congenital heart disease adding functional information undetectable with other imaging modalities.     

Dynamic magnetic resonance imaging of swallowing and laryngeal motion using parallel imaging at 3 T

Object

To evaluate the feasibility of an optimized MRI protocol based on high field imaging at 3 T in combination with accelerated data acquisition by parallel imaging for the analysis of oropharyngeal and laryngeal function.

Materials and Methods

Fast 2D gradient echo (GRE) MRI with different spatial resolutions (1.7×2.7 and 1.1×1.5 mm²) and image update rates (4 and 10 frames per second) was employed to assess pharyngeal movements and visualize swallowing via tracking of an oral contrast bolus (blueberry juice). In a study with 10 normal volunteers, image quality was semi-quantitatively graded by three independent observers with respect to the delineation of anatomical detail and depiction of oropharynx and larynx function. Additionally, the feasibility of the technique for the visualization of pathological pre- and post-surgical oropharynx and larynx function was evaluated in a patient with inspiratory stridor.

Results

Image grading demonstrated the feasibility of dynamic MRI for the assessment of normal oropharynx and larynx anatomy and function. Superior image quality (P<.05) was found for data acquisition with four frames per second and higher spatial resolution. In the patient, dynamic MRI detected pathological hypermobility of the epiglottis resulting in airway obstruction. Additional post-surgical MRI for one clinical case revealed morphological changes of the epiglottis and improved function, i.e., absence of airway obstruction and normal swallowing.

Conclusion

Results of the volunteer study demonstrated the feasibility of dynamic MRI at 3 T for the visualization of the oropharynx and larynx function during breathing, movements of the tongue and swallowing. Future studies are necessary to evaluate its clinical value compared to existing modalities based on endoscopy or radiographic techniques.     

Central neurocytoma: proton MR spectroscopy and diffusion weighted MR imaging findings

Purpose

To present proton magnetic resonance spectroscopy and diffusion-weighted imaging (DWI) findings of central neurocytoma (CN).

Methods and Materials

Imaging findings of seven patients with the histopathological diagnosis of CN (five male and two female; age range, 21–28 years of age) were evaluated retrospectively. In addition to conventional magnetic resonance imaging features, we also assessed the metabolite ratios and tumor normalized apparent diffusion coefficient (NADC), which was calculated by dividing the tumor apparent diffusion coefficient (ADC) values by normal ADC. Approval from our institutional review board was obtained for this review.

Results

The tumor choline/creatine ratios were 5.17±2.38, while N-acetyl aspartate/choline and N-acetyl aspartate/creatine ratios were 0.33±0.15 and 1.84±1.38, respectively. On DWI, tumors had heterogeneous hyperintense appearances when compared with the contralateral parietal lobe white matter and tumor NADC values were 0.63±0.05.

Conclusion

Significantly increased choline/creatine and decreased N-acetyl aspartate/choline ratios with lower NADC values in CN resemble high-grade gliomas and complicate the diagnosis. Familarity its physiologic features would help to presurgical diagnosis of ventricular and exraventricular CNs.     

In vitro assessment of MRI issues at 3-Tesla for a breast tissue expander with a remote port

Objectives

A patient with a breast tissue expander may require a diagnostic assessment using magnetic resonance imaging (MRI). To ensure patient safety, this type of implant must undergo in vitro MRI testing using proper techniques. Therefore, this investigation evaluated MRI issues (i.e., magnetic field interactions, heating, and artifacts) at 3-Tesla for a breast tissue expander with a remote port.

Methods

A breast tissue expander with a remote port (Integra Breast Tissue Expander, Model 3612-06 with Standard Remote Port, PMT Corporation, Chanhassen, MN) underwent evaluation for magnetic field interactions (translational attraction and torque), MRI-related heating, and artifacts using standardized techniques. Heating was evaluated by placing the implant in a gelled-saline-filled phantom and MRI was performed using a transmit/receive RF body coil at an MR system reported, whole body averaged specific absorption rate of 2.9-W/kg. Artifacts were characterized using T1-weighted and GRE pulse sequences.

Results

Magnetic field interactions were not substantial and, thus, will not pose a hazard to a patient in a 3-Tesla or less MRI environment. The highest temperature rise was 1.7 °C, which is physiologically inconsequential. Artifacts were large in relation to the remote port and metal connector of the implant but will only present problems if the MR imaging area of interest is where these components are located.

Conclusions

A patient with this breast tissue expander with a remote port may safely undergo MRI at 3-Tesla or less under the conditions used for this investigation. These findings are the first reported at 3-Tesla for a tissue expander.