Diagnostic Magnetic Resonance Imaging Scans Research Articles

Using prostate-specific membrane antigen positron-emission tomography to guide prostate biopsies and stage men at high-risk of prostate cancer.

To assess whether a diagnostic pathway in which prostate-specific membrane antigen (PSMA) positron-emission tomography (PET)/computed tomography (CT) is used as a single imaging modality is feasible to guide targeted biopsy and to detect clinically significant prostate cancer (csPCa) in biopsy-naïve men at high-risk of disease. A total of 60 men with a prostate-specific antigen (PSA) level of 20-50 ng/mL underwent 18 F-PSMA(DCFPyL)-PET/CT prior to prostate biopsies in this prospective, non-randomised cohort study. Magnetic resonance imaging (MRI) was not performed. Using a 12-segment mapping model of the prostate, PSMA-guided targeted biopsy was performed along with systematic biopsies. The detection rate of PCa and csPCa was assessed for combined systematic and targeted biopsy, and for targeted biopsy only. csPCa was defined as a prostate biopsy with an International Society of Uropathology (ISUP) Grade Group ≥2. Lesions suspicious for PCa in the prostate gland were observed on all PSMA-PET/CTs. A total of 27/60 men (45%) already had metastatic disease on staging 18 F-PSMA(DCFPyL)-PET/CT. Combined PSMA-guided targeted and systematic biopsies detected PCa in 56/60 (93.3%) patients, with 52 of them (92.9%) having csPCa. PSMA-guided targeted biopsy, if performed as a single biopsy modality, identified PCa in 52/60 men (86.7%) and in 27/27 men (100%) men with metastases. Using the PSMA-driven single imaging modality pathway in biopsy-naïve men at high-risk of PCa, a substantial number of diagnostic MRI scans could be avoided while at the same time obtaining adequate targeting, staging, and detection of csPCa.

MRI Characteristics of Pediatric and Young-Adult Renal Cell Carcinoma: A Single-Center Retrospective Study and Literature Review

Pediatric renal cell carcinoma (RCC) is a rare malignancy. Magnetic resonance imaging (MRI) is the preferred imaging modality for assessment of these tumors. The previous literature has suggested that cross-sectional-imaging findings differ between RCC and other pediatric renal tumors and between RCC subtypes. However, studies focusing on MRI characteristics are limited. Therefore, this study aims to identify MRI characteristics of pediatric and young-adult RCC, through a single-center case series and literature review. Six identified diagnostic MRI scans were retrospectively assessed, and an extensive literature review was conducted. The included patients had a median age of 12 years (63-193 months). Among other subtypes, 2/6 (33%) were translocation-type RCC (MiT-RCC) and 2/6 (33%) were clear-cell RCC. Median tumor volume was 393 cm3 (29-2191 cm3). Five tumors had a hypo-intense appearance on T2-weighted imaging, whereas 4/6 were iso-intense on T1-weighted imaging. Four/six tumors showed well-defined margins. The median apparent diffusion coefficient (ADC) values ranged from 0.70 to 1.20 × 10-3 mm2/s. In thirteen identified articles focusing on MRI characteristics of MiT-RCC, the majority of the patients also showed T2-weighted hypo-intensity. T1-weighted hyper-intensity, irregular growth pattern and limited diffusion-restriction were also often described. Discrimination of RCC subtypes and differentiation from other pediatric renal tumors based on MRI remains difficult. Nevertheless, T2-weighted hypo-intensity of the tumor seems a potential distinctive characteristic.

Retrospective Analysis of Treatment Workflow in Frame-Based and Frameless Gamma Knife Radiosurgery.

ObjectiveTo improve the efficiency of frame-based and frameless Gamma Knife® Icon™ (GKI) treatments by analyzing the workflows of both treatment approaches and identifying steps that lead to prolonged patient in-clinic or treatment time.MethodsThe treatment processes of 57 GKI patients, 16 frame-based and 41 frameless cases were recorded and analyzed. For frame-based treatments, time points were recorded for various steps in the process, including check-in, magnetic resonance imaging (MRI) completion, plan approval, and treatment start/end times. The time required for completing each step was calculated and investigated. For frameless treatments, the actual and planned treatment times were compared to evaluate the patient tolerance of the treatment. In addition, the time spent on room cleaning and preparation between treatments was also recorded and analyzed.ResultsFor frame-based cases, the average in-clinic time was 6.3 hours (ranging from 4 to 8.7 hours). The average time from patient check-in to plan approval was 4.2 hours (ranging from 2.8 to 5.5 hours), during which the frame was placed, stereotactic reference MRI images were taken, target volumes were contoured, and the treatment plan was developed and second-checked. For patients immobilized with a mask, treatment pauses triggered by the intra-fractional motion monitoring system resulted in a significantly longer actual treatment time than the planned time. In 50 (or 55%) of the 91 frameless treatments, the patient on-table time was longer than the planned treatment time by more than 10 minutes, and in 19 (or 21%) of the treatments the time difference was larger than 20 minutes. Major treatment interruptions, defined as pauses leading to a longer than 10-minute delay, were more commonly encountered in patients with a planned treatment time longer than 40 minutes, which accounted for 64% of the recorded major interruptions.ConclusionFor frame-based cases, the multiple pretreatment steps (from patient check-in to plan approval) in the workflow were time-consuming and resulted in prolonged patient in-clinic time. These pretreatment steps may be shortened by performing some of these steps before the treatment day, e.g., pre-planning the treatment using diagnostic MRI scans acquired a few days earlier. For frameless patients, we found that a longer planned treatment time is associated with a higher chance of treatment interruption. For patients with a long treatment time, a planned break or consideration of fractionated treatments (i.e., 3 to 5 fractionated stereotactic radiosurgery) may optimize the workflow and improve patient satisfaction.

Diffusional kurtosis imaging as a possible prognostic marker of cervical incomplete spinal cord injury outcome: a prospective pilot study.

Spinal cord injury (SCI) is associated with substantial chronic morbidity and mortality. Routine imaging techniques such as T1- and T2-weighted magnetic resonance imaging (MRI) are not effective in predicting neurological deficiency grade or outcome. Diffusional kurtosis imaging (DKI) is an MR imaging technique that provides microstructural information about biological tissue. There are no longitudinal prospective studies assessing DKI metrics in acute traumatic SCI. Therefore, the purpose of this study was to establish a DKI protocol for acute SCI and correlate the DKI metrics to the functional neurological outcome of the patients. Eight consecutive SCI patients referred to our institution with cervical SCI were included in the study. An acute diagnostic MRI scan was supplemented with a novel fast, mean kurtosis DKI protocol, which describes the average deviation from Gaussian diffusional along nine different directions. Mean kurtosis values were measured at the injury site and normalized to the mean kurtosis values of a non-injured site. At discharge form specialized rehabilitation, patients were evaluated using the Spinal Cord Independence Measure-III (SCIM-III). The DKI metrics and SCIM-III were analysed using Spearman's rank correlation. This pilot study found a significant correlation between decreasing mean kurtosis values at the injury site of the spinal cord and higher grade of disability measured by the SCIM-III (p = 0.002). This pilot study found that DKI may be a valuable tool as a prognostic marker in the acute phase of SCI.

Magnetic Resonance Imaging Around Metal at 1.5 Tesla: Techniques From Basic to Advanced and Clinical Impact.

During the last decade, metal artifact reduction in magnetic resonance imaging (MRI) has been an area of intensive research and substantial improvement. The demand for an excellent diagnostic MRI scan quality of tissues around metal implants is closely linked to the steadily increasing number of joint arthroplasty (especially knee and hip arthroplasties) and spinal stabilization procedures. Its unmatched soft tissue contrast and cross-sectional nature make MRI a valuable tool in early detection of frequently encountered postoperative complications, such as periprosthetic infection, material wear-induced synovitis, osteolysis, or damage of the soft tissues. However, metal-induced artifacts remain a constant challenge. Successful artifact reduction plays an important role in the diagnostic workup of patients with painful/dysfunctional arthroplasties and helps to improve patient outcome. The artifact severity depends both on the implant and the acquisition technique. The implant's material, in particular its magnetic susceptibility and electrical conductivity, its size, geometry, and orientation in the MRI magnet are critical. On the acquisition side, the magnetic field strength, the employed imaging pulse sequence, and several acquisition parameters can be optimized. As a rule of thumb, the choice of a 1.5-T over a 3.0-T magnet, a fast spin-echo sequence over a spin-echo or gradient-echo sequence, a high receive bandwidth, a small voxel size, and short tau inversion recovery-based fat suppression can mitigate the impact of metal artifacts on diagnostic image quality. However, successful imaging of large orthopedic implants (eg, arthroplasties) often requires further optimized artifact reduction methods, such as slice encoding for metal artifact correction or multiacquisition variable-resonance image combination. With these tools, MRI at 1.5 T is now widely considered the modality of choice for the clinical evaluation of patients with metal implants.

A Dosimetric Comparison of Pelvic Lymph Node Volume Delineation Using Magnetic Resonance Imaging Versus Computed Tomography in Gynecological Cancers

Definitive external beam radiotherapy (EBRT) targets the primary tumor and at-risk pelvic lymph node groups. Magnetic resonance imaging (MRI), with its superior soft tissue definition compared with computed tomography (CT), is routinely used in cervical cancer EBRT planning to accurately define the primary tumor. MRI can also provide more accurate visualization of lymph nodes, vessels and tissue planes, such that MRI-based nodal clinical target volume (CTVn) delineation may result in smaller volumes and reduced dose to organs at risk (OAR). The aim of this study was to dosimetrically compare EBRT plans in patients with CTVn delineation using MRI fused with CT (CT-MRI) and CT alone. This study was important to examine the advantage of MRI in radiotherapy; prior to the addition of a new MRI simulator and MRI Linac in our center. Nine patients with cervical cancer and two patients with recurrent endometrial cancer were treated using definitive EBRT at our institution with diagnostic MRI scans and were included in this study. The planning CT (pCT) scan for each patient was obtained and fused with T2-weighted MRI scan using bony landmarks and deformable registration. Two separate CTVn volumes were contoured by a radiation oncologist, one based on pCT and a second based on MRI. All other structures including primary CTV (CTVp) and OAR (rectum, sigmoid, bowel, bladder, and femurs) were contoured on the pCT only. Planning target volume (PTV) contours were created by combining CTVn and CTVp with a 1 cm margin. Volumetric modulated arc therapy (VMAT) plans were generated for both pCT-based PTVs and CT-MRI-based PTVs using institutional protocol. Plans were evaluated for PTV volume, coverage (D98) and dose to OAR. Differences between pCT and CT-MRI were analyzed using paired t-tests and results are presented as means and SD (standard deviation). Twenty-two VMAT plans were generated. The mean (SD) PTV volume was 1485.9 cm³ (171.7) for pCT and 1424.5 cm³ (168.0) for the CT-MRI plan (p<0.001). The mean (SD) PTV D98 for pCT and CT-MRI was the same at 43.1 Gy (0.3) (p = 0.677). There was no significant dosimetric difference noted to any of the OAR (Table). This novel method for reducing the CTVn volume by using MRI to avoid anatomical boundaries such as fascial planes and bowel produced an overall reduction in the target volume. However, this did not result in a dosimetric advantage to the surrounding OAR. The most clinically relevant benefit of MRI in gynecological EBRT planning remains in the accurate definition of the primary tumor.Tabled 1Abstract 3080; Table;Organ at RiskpCT, Mean (SD)CT-MRI, Mean (SD)p-valueRectum (V40)56.9% (5.2)49.8% (11.8)0.111Sigmoid (V40)82.2% (20.6)78.7% (28.7)0.588Sigmoid (V45)27.5% (13.9)26.5% (17.8)0.787Bowel (V40)197.8cm³ (97.8)210.8cm³ (103.5)0.605Bowel (V45)73.3cm³ (43.1)67.3cm³ (45.9)0.664Bladder (V45)22.5% (4.1)24.5% (5.9)0.172Right Femur (V30)10.9% (2.3)10.3% (2.9)0.458Left Femur (V30)12.0% (3.1)11.6% (2.2)0.570 Open table in a new tab

Easing anxiety in preparation for pediatric magnetic resonance imaging: a pilot study using animal-assisted therapy.

Children undergoing magnetic resonance imaging (MRI) can experience negative emotions both before and during their scan, causing them to move and often necessitating the use of procedural sedation. Several strategies to improve patient compliance have been attempted. This study was designed to evaluate the effectiveness of a non-pharmacological intervention to reduce anxiety in pediatric patients preparing for MRI using animal-assisted therapy. An animal intervention pilot study was performed in patients who agreed in advance to interact with a dog. Patients and caregivers filled out questionnaires, including questions designed to capture changes in patient emotion before and after the intervention. MRI diagnostic quality was compared to age- and gender-matched control groups with and without general anesthesia. The intervention in 21 patients comparing pre- and post-scan surveys demonstrated a statistically significant improvement in patient anxiety levels (P<0.01). Diagnostic MRI scans were achieved in 19/21 (90%), with no significant difference in exam quality or times compared against control groups. The majority of caregivers and staff members agreed strongly that patients benefited from the therapy dog's presence. The use of animal-assisted therapy in a pilot group in our MRI division resulted in a beneficial effect on patients' emotional status, easing anxiety in preparation for scheduled scans, without impacting MRI quality or duration. Further randomized studies will be needed to demonstrate its significance in reducing sedation rates in children undergoing MRI.

A comparative study based on deformable image registration of the target volumes for external-beam partial breast irradiation defined using preoperative prone magnetic resonance imaging and postoperative prone computed tomography imaging

BackgroundTo explore the differences and correlations between the target volumes defined using preoperative prone diagnostic magnetic resonance imaging (MRI) and postoperative prone computed tomography (CT) simulation imaging based on deformable image registration (DIR) for external-beam partial breast irradiation (EB-PBI) after breast-conserving surgery (BCS).MethodsEighteen breast cancer patients suitable for EB-PBI were enrolled. Preoperative prone diagnostic MRI and postoperative prone CT scan sets for all the patients were acquired during free breathing. Target volumes and ipsilateral breast were all contoured by the same radiation oncologist. The gross tumor volume (GTV) delineated on the preoperative MRI images was denoted as the GTVpreMR and the tumor bed (TB) delineated on the postoperative prone CT images was denoted as the GTVpostCT. The MIM software system was used to deformably register the MRI and CT images.ResultsWhen based on the coincidence of the compared target centers, there were statistically significant increases in the conformity index (CI) and degree of inclusion (DI) values for GTVpostCT-GTVpreMR, GTVpostCT-CTVpreMR + 10, CTVpostCT + 10-GTVpreMR, and CTVpostCT + 10-CTVpreMR + 10 when compared with those based on the DIR of the thorax (Z = − 3.724, − 3.724, − 2.591, − 3.593, all P < 0.05; Z = -3.724, − 3.724, − 3.201, − 3.724, all P < 0.05, respectively).ConclusionsAlthough based on DIR, there was relatively poor spatial overlap between the preoperative prone diagnostic MRI images and the postoperative prone CT simulation images for either the whole breast or the target volumes. Therefore, it is unreasonable to use preoperative prone diagnostic MRI images to guide postoperative target delineation for EB-PBI.

Novel Use of 0.35T MRI Guidance for High Dose Rate Brachytherapy in the Treatment of Cervical Cancer

Intracavitary brachytherapy planning for gynecologic malignancies has previously relied on clinical set up, plain films, computed tomography (CT) and 3T diagnostic magnetic resonance imaging (MRI) guidance. We report the use of 0.35T MRI-guided brachytherapy planning for gynecologic malignancies at our institution, which we hypothesize would allow for shorter time to treatment, and shorter imaging times with relatively high-degree of image quality. Patients undergoing intracavitary brachytherapy with tandem and ovoid +/- interstitial parametrial needles for cervical malignancies at our institution who received treatment planned using the 0.35T MRI were reviewed. The high-risk CTV (HR-CTV), GTV (if visualized), bladder, sigmoid, nearby small bowel, and rectum were contoured. Typically, patients receiving 5 fractions of intracavitary brachytherapy would undergo planning using diagnostic MRI for the first and third fractions, and using 0.35T MRI, or CT scan, for the second, fourth, and fifth fractions. In all, 29 patients fit inclusion criteria from April 2015 to January 2017, ranging from stage IB1 to IVA (IB1: 9 patients; IB2: 1 patients; IIA1: 2 patients; IIA2: 3 patients; IIB: 7 patients; IIIB: 6 patients; IVA: 1 patient). A 0.35T non-contrast MRI was obtained while the tandem and ovoid instruments +/- interstitial needles were in place. Most patients received 5.5Gy x 5 fractions to the HR-CTV using high dose rate Ir-192 following 45Gy of external beam radiotherapy to the pelvis +/- simultaneous integrated boost to imaging-abnormal lymph nodes to 55 Gy. For all patients, the median HR-CTV size was 27.78cc, and the median D90 to the HR-CTV was 6.1Gy. The median D2cc to the bladder, rectum, bowel, and sigmoid were 5Gy, 2.5Gy, 2.6Gy, and 3Gy, respectively. The image acquisition time was approximately 2.5 min for the 0.35T MRI, and 15min for the diagnostic MRI. The median time from imaging start to initiation of treatment using the 0.35T MRI scan was 65min, compared to 105min using diagnostic MRI scan, (t-test, p < 0.01). The contrast-to-noise ratio (CNR) of tumor to cervix was significantly higher in the diagnostic MRI compared to 0.35T MRI; both diagnostic and 0.35T MRI scans had significantly higher CNR values compared to CT, (ANOVA and Tukey pair-wise tests, p<0.01). We report the first clinical use of 0.35T MRI-guided brachytherapy. The treatment using this approach expedited the image acquisition compared to diagnostic MRI, and provided significant advantage in visualizing the tumor and cervix compared to CT. This presents a feasible and reliable manner to image and plan gynecologic brachytherapy.

Morphologic Features of Magnetic Resonance Imaging as a Surrogate of Capsular Contracture in Breast Cancer Patients With Implant-based Reconstructions

Capsular contracture (CC) is a serious complication in patients receiving implant-based reconstruction for breast cancer. Currently, no objective methods are available for assessing CC. The goal of the present study was to identify image-based surrogates of CC using magnetic resonance imaging (MRI). We analyzed a retrospective data set of 50 patients who had undergone both a diagnostic MRI scan and a plastic surgeon's evaluation of the CC score (Baker's score) within a 6-month period after mastectomy and reconstructive surgery. The MRI scans were assessed for morphologic shape features of the implant and histogram features of the pectoralis muscle. The shape features, such as roundness, eccentricity, solidity, extent, and ratio length for the implant, were compared with the Baker score. For the pectoralis muscle, the muscle width and median, skewness, and kurtosis of the intensity were compared with the Baker score. Univariate analysis (UVA) using a Wilcoxon rank-sum test and multivariate analysis with the least absolute shrinkage and selection operator logistic regression was performed to determine significant differences in these features between the patient groups categorized according to their Baker's scores. UVA showed statistically significant differences between grade 1 and grade ≥2 for morphologic shape features and histogram features, except for volume and skewness. Only eccentricity, ratio length, and volume were borderline significant in differentiating grade ≤2 and grade ≥3. Features with P<.1 on UVA were used in the multivariate least absolute shrinkage and selection operator logistic regression analysis. Multivariate analysis showed a good level of predictive power for grade 1 versus grade ≥2 CC (area under the receiver operating characteristic curve 0.78, sensitivity 0.78, and specificity 0.82) and for grade ≤2 versus grade ≥3 CC (area under the receiver operating characteristic curve 0.75, sensitivity 0.75, and specificity 0.79). The morphologic shape features described on MR images were associated with the severity of CC. MRI has the potential to further improve the diagnostic ability of the Baker score in breast cancer patients who undergo implant reconstruction.

Comparison of Computed Tomography– and Magnetic Resonance Imaging–based Clinical Target Volume Contours at Brachytherapy for Cervical Cancer

We prospectively compared computed tomography (CT)- and magnetic resonance imaging (MRI)-based high-risk clinical target volume (HR-CTV) contours at the time of brachytherapy for cervical cancer in an effort to identify patients who might benefit most from MRI-based planning. Thirty-seven patients who had undergone a pretreatment diagnostic MRI scan were included in the analysis. We delineated the HR-CTV on the brachytherapy CT and brachytherapy MRI scans independently for each patient. We then calculated the absolute volumes for each HR-CTV and the Dice coefficient of similarity (DC, a measure of spatial agreement) for the HR-CTV contours. We identified the clinical and tumor factors associated with (1) a discrepancy in volume between the CT HR-CTV and MRI HR-CTV contours; and (2) DC. The mean values were compared using 1-way analysis of variance or paired or unpaired t tests, as appropriate. Simple and multivariable linear regression analyses were used to model the effects of covariates on the outcomes. Patients with International Federation of Gynecology and Obstetrics stage IB to IVA cervical cancer were treated with intracavitary brachytherapy using tandem and ovoid (n=33) or tandem and cylinder (n=4) applicators. The mean CT HR-CTV volume (44.1cm3) was larger than the mean MRI HR-CTV volume (35.1cm3; P<.0001, paired t test). On multivariable analysis, a higher body mass index (BMI) and tumor size ≥5cm with parametrial invasion on the MRI scan at diagnosis were associated with an increased discrepancy in volume between the HR-CTV contours (P<.02 for both). In addition, the spatial agreement (as measured by DC) between the HR-CTV contours decreased with an increasing BMI (P=.013). We recommend MRI-based brachytherapy planning for patients with tumors >5cm and parametrial invasion on MRI at diagnosis and for those with a high BMI.

Magnetic resonance imaging for precise radiotherapy of small laboratory animals

AimsRadiotherapy of small laboratory animals (SLA) is often not as precisely applied as in humans. Here we describe the use of a dedicated SLA magnetic resonance imaging (MRI) scanner for precise tumor volumetry, radiotherapy treatment planning, and diagnostic imaging in order to make the experiments more accurate. Methods and materialsDifferent human cancer cells were injected at the lower trunk of pfp/rag2 and SCID mice to allow for local tumor growth. Data from cross sectional MRI scans were transferred to a clinical treatment planning system (TPS) for humans. Manual palpation of the tumor size was compared with calculated tumor size of the TPS and with tumor weight at necropsy. As a feasibility study MRI based treatment plans were calculated for a clinical 6MV linear accelerator using a micro multileaf collimator (μMLC). In addition, diagnostic MRI scans were used to investigate animals which did clinical poorly during the study. ResultsMRI is superior in precise tumor volume definition whereas manual palpation underestimates their size. Cross sectional MRI allow for treatment planning so that conformal irradiation of mice with a clinical linear accelerator using a μMLC is in principle feasible. Several internal pathologies were detected during the experiment using the dedicated scanner. ConclusionMRI is a key technology for precise radiotherapy of SLA. The scanning protocols provided are suited for tumor volumetry, treatment planning, and diagnostic imaging.

Dosimetric analysis of varying cord planning organ at risk volume in spine stereotactic body radiation therapy

BackgroundSpine stereotactic body radiation therapy (SBRT) is becoming widely accepted as first-line treatment of oligometastatic spine disease as well as in the postoperative setting. The reported incidence of myelopathy is very low and guidelines vary widely on the maximum tolerable dose of the spinal cord and thecal sac. Methods and materialsBetween April 2008 and December 2010, radiation parameters were exported for 46 patients treated with spine SBRT at the Mayo Clinic. Using an in-house data mining program, dose-volume histogram constraints were extracted, including dose prescription, dose fractionation, planning target volume, planning target volume coverage, maximum dose to the cord, D2cc thecal sac, and D2cc spinal cord. Diagnostic magnetic resonance imaging scans and/or computed tomography myelograms were fused with the planning set to delineate the cord and thecal sac for receiver operating characteristic analysis of cord and thecal sac subvolume doses. A high-resolution planning at-risk volume was created in 1-mm increments for cord (1-7 mm) and the thecal sac (1-2 mm) to examine dose gradients that might be correlated with toxicity. ResultsNo patients experienced myelopathy with a median follow-up of 14 months. The most common toxicities were pain and nausea. Median values of D2cc maximum dose (maximum dose received by 2 cc of the organ at risk; biologically equivalent 2-Gy dose maximum [EQD2]) for cord and thecal sac were 38.5 Gy (range, 7.5-67.9 Gy) and 67.7 Gy (range, 15.5-155.8 Gy), respectively. Median values for high-dose subvolumes for cord and thecal sac were 2 times higher than the doses for 5% predicted grade 3 cord toxicity as recommended in the current literature. Cord D0.1cc[EQD2] ≥23.8 Gy was correlated with pain flare (n = 5). Thecal sac D2cc [EQD2] ≥29.3 Gy was a significant indicator of nausea. ConclusionCurrent guidelines may overestimate the risk of myelopathy from spine SBRT. The current study's population included both radiation-naïve and retreatment cases, but no myelopathy was observed despite exceeding recommended spine limits.

Surgical Treatment of Spinal Dural Arteriovenous Fistula: Management and Long-Term Outcome in a Single-Center Series

To perform a retrospective chart review of surgically treated patients with spinal dural arteriovenous fistula (SDAVF), a rare disease but the most common vascular malformation of the spine, focusing on clinical characteristics and functional outcome during long-term follow-up. Between June 1990 and April 2012, 29 patients with SDAVFs were treated surgically in a single institution. Patient characteristics, time from onset of symptoms to treatment, radiologic features, treatment-related complications, and functional outcome were analyzed. Outcome was assessed according to the Aminoff-Logue scale during follow-up. Results of magnetic resonance imaging scans performed during long-term follow-up were correlated with functional outcome. There were 3 female (10%) and 26 male (90%) patients with SDAVFs treated surgically. Mean age was 61 years ± 11. Location of the fistula was at the thoracic level in 20 patients (69%), at the lumbar level in 8 patients (28%), and at the sacral level in 1 patient (3%). Mean postoperative Aminoff-Logue scale scores regarding gait and micturition improved after treatment compared with preoperatively (P = 0.02; P = 0.03). After surgical treatment, 22 patients (76%) achieved improvement in neurologic symptoms. In 6 patients (21%), neurologic status was the same as preoperatively. In 1 patient (3%), neurologic status worsened. Medullary signal alteration of diagnostic magnetic resonance imaging scans did not correlate with functional outcome (P = 0.2). Mean follow-up time was 63 months ± 55. All SDAVFs were treated in a single session without recurrence during the long-term follow-up period. Surgical treatment of SDAVFs is safe and effective and leads to an improvement of neurologic symptoms in most patients. Surgical treatment of SDAVFs also provides long-term stability.

O7.02 * RADIOSURGERY AND BRAIN METASTASES: ADEQUATE SEQUENCE OF BRAIN MRI CAN SIGNIFICANTLY CHANGE THE INTRACRANIAL DISEASE STAGING

INTRODUCTION: Accurate assessment of the exact number of brain metastases is of utmost importance in the decision-making process for the appropriate treatment. The diagnostic efficacy in the detection of additional brain metastases of a double dose contrast three-dimensional, T1-Weighted Gradient-Echo Imaging was evaluated. METHODS: Before undergoing radiosurgical treatment, patients underwent a brain magnetic resonance imaging (MRI) scan to be used during the treatment planning in order to contour the targets and to locate the brain lesions as they relate to the stereotactic frame. All the patients underwent a post-contrast study with T1-weighted, 3D Magnetization-Prepared Rapid Acquisition Gradient Echo (MP RAGE) sequence. We used a double dose of gadobenate dimeglumine and slice thickness of 0.9 mm. RESULTS: Starting from October 2012 to February 2014, we treated with Gamma Knife radiosurgery (GKRS) 62 patients with brain metastases. On the diagnostic MRI, all the patients had a number of lesions ≤4. Median time interval between diagnostic MRI scan and the day of GKRS was 11 days (range 5-20) A total of 54 additional lesions were detected on MR imaging performed in the same day of the GKRS in twenty-two patients out of 62 (35.5%). A median number of 2 additional lesions were detected (range 1-8). Among these 22 patients only 14 patients had a number of lesions ≤4 on the day of treatment. Patients with a total number of lesions ≤10 were treated with GKRS. Two patients with a total number of lesions > 10 were treated with whole brain radiotherapy (WBRT). CONCLUSIONS: A double-contrast study with T1-weighted, volumetric MPRAGE sequence may offer better staging for patients with brain metastases. In our opinion, it should be recommended in all the patients with newly diagnosed brain metastases because the detection of the real number of lesions is crucial for an adequate treatment and it also may lead to choose different therapeutic strategies.

A Royal College of Radiologists National Audit of Radiotherapy in the Treatment of Metastatic Spinal Cord Compression and Implications for the Development of Acute Oncology Services

AimsTo audit the current use of radiotherapy in UK cancer centres for the treatment of metastatic spinal cord compression against national standards that seek to optimise functional and quality of life outcomes. Materials and methodsA Royal College of Radiologists prospective national audit of patients treated with radiotherapy in UK cancer centres was carried out over a 3 month period between September and December 2008, with a repeat audit carried out in August 2012. ResultsFive hundred and ninety-six cases were received from 42 cancer centres (74%) in 2008, with data from 323 cases received from 52 (90%) centres in 2012. Ninety-three per cent (358) of patients had a diagnostic magnetic resonance imaging scan carried out within 24 h of referral for radiotherapy in 2008 compared with 205 patients (97%) in 2012. One hundred and eleven (32%) good prognosis patients were discussed with spinal surgeons; only 10 good prognosis patients were recorded as proceeding to surgery in 2008. This improved in 2012, with 94 (41% of good prognosis patients recorded as having been discussed with nine proceeding to surgery). Sixty-nine per cent of paraplegic patients in 2008 received multiple fractions of radiotherapy, which was similar to 2012 when 62% received more than a single fraction. A metastatic spinal cord compression co-ordinator was available in just over 50% of cases (164/323) and was involved in patient management in 26% of cases in 2012. ConclusionDespite level 1 evidence of the superior functional outcome and survival benefit for surgery, few good prognosis patients were recorded as having been discussed with surgeons and even fewer proceeded to surgery.

Utility of Cardiac Magnetic Resonance Imaging to Differentiate Cardiac Sarcoidosis from Arrhythmogenic Right Ventricular Cardiomyopathy

Some patients diagnosed with arrhythmogenic right ventricular cardiomyopathy (ARVC) are eventually found to have cardiac sarcoidosis (CS). Accurate differentiation between these 2 conditions has implications for immunosuppressive therapy and familial screening. We sought to determine whether cardiac magnetic resonance imaging (MRI) could be used to identify the characteristic findings to accurately differentiate between CS and ARVC. Consecutive patients with a diagnostic MRI scan indicating CS and/or ARVC constituted the cohort. All patients diagnosed with CS had histologic confirmation of sarcoidosis, and all patients with ARVC met the diagnostic task force criteria. The cardiac MRI data were retrospectively analyzed to identify possible differentiating characteristics. Of the patients, 40 had CS and 21 had ARVC. Those with CS were older and had more left ventricular scar. The presence of mediastinal lymphadenopathy or left ventricular septal involvement was seen exclusively in the patients with CS (p <0.001). A family history of sudden cardiac death was seen only in the ARVC group (p = 0.012). The right ventricular ejection fraction and ventricular volumes were also significantly different between the 2 groups. In conclusion, patients with CS have significantly different cardiac MRI characteristics than patients with ARVC. The cardiac volume, in addition to the degree and location of cardiac involvement, can be used to distinguish between these 2 disease entities. The presence of mediastinal lymphadenopathy and left ventricular septal scar favors a diagnosis of CS and not ARVC. Consideration of CS should be given if these MRI findings are observed during the evaluation for possible ARVC.

Preparing children with a mock scanner training protocol results in high quality structural and functional MRI scans

We evaluated the use of a mock scanner training protocol as an alternative for sedation and for preparing young children for (functional) magnetic resonance imaging (MRI). Children with severe mental retardation or developmental disorders were excluded. A group of 90 children (median age 6.5 years, range 3.65–14.5 years) participated in this study. Children were referred to the actual MRI investigation only when they passed the training. We assessed the pass rate of the mock scanner training sessions. In addition, the quality of both structural and functional MRI (fMRI) scans was rated on a semi-quantitative scale. The overall pass rate of the mock scanner training sessions was 85/90. Structural scans of diagnostic quality were obtained in 81/90 children, and fMRI scans with sufficient quality for further analysis were obtained in 30/43 of the children. Even in children under 7 years of age, who are generally sedated, the success rate of structural scans with diagnostic quality was 53/60. FMRI scans with sufficient quality were obtained in 23/36 of the children in this younger age group. The association between age and proportion of children with fMRI scans of sufficient quality was not statistically significant. We conclude that a mock MRI scanner training protocol can be useful to prepare children for a diagnostic MRI scan. It may reduce the need for sedation in young children undergoing MRI. Our protocol is also effective in preparing young children to participate in fMRI investigations.

Overlap in Frontotemporal Atrophy Between Normal Aging and Patients With Frontotemporal Dementias

Normal aging leads to frontocortical atrophy. The degree to which this complicates the use of frontotemporal atrophy as a diagnostic criterion for the frontotemporal dementias (FTDs) has not been reported. The present case-control study compared frontotemporal volumes delineated with semi-automatic brain region extraction [n=30 controls vs. 16 behavioral variant FTD (bvFTD) vs. 14 primary progressive aphasia]. Logistic regression identified those regions least helpful for distinguishing bvFTD and primary progressive aphasia from controls. Linear regression tested the correlation of duration of illness to atrophy severity. The control group showed high variance in volumes. Controls had right frontal lobe volumes that overlapped considerably with bvFTD volumes, but, as anticipated, the left anterior temporal volumes of interest showed 91% accuracy in distinguishing the aphasic subgroup from controls. Left-sided and not right-sided atrophy in the medial middle frontal region distinguished the bvFTD group from controls. The relegation of structural imaging to a supportive criterion for diagnosis is reasonable in the context of the range of atrophy due to normal aging. While volumetry identified left-sided atrophy as useful for identifying FTD cases, future studies should determine whether clinicians could make these distinctions on viewing routine diagnostic magnetic resonance imaging scans.

Diagnostic Comparison of 1.5 Tesla and 3.0 Tesla Preoperative MRI of the Wrist in Patients With Ulnar-Sided Wrist Pain

The diagnostic sensitivity, specificity, and accuracy of 1.5 Tesla (T) and of 3.0T magnetic resonance imaging (MRI) are correlated with wrist arthroscopy findings in patients presenting with ulnar-sided wrist pain. The records and diagnostic MRI scans of 102 patients who presented between 1997 and 2006 with ulnar-sided wrist pain were evaluated. Preoperative MRI scans at 1.5T (n = 70) and 3.0T (n = 32) were evaluated by 2 experienced musculoskeletal radiologists with different levels of experience who were blinded to the arthroscopic findings. Preoperative MRI findings for the triangular fibrocartilage complex (TFCC), scapholunate, ulnotriquetral, and lunotriquetral ligaments were recorded and compared with findings at diagnostic arthroscopy. The sensitivity, specificity, and accuracy were calculated for both the 1.5T and 3.0T preoperative MRI scans. Statistical comparisons were made using chi-square test and JMP 6.0 software. A tear of the TFCC was identified retrospectively on 1.5T images in 49 of 58 patients and on 3.0T images in 15 of 16 patients. Compared with the gold standard of arthroscopy, 1.5T wrist MRI in this patient population had a sensitivity of 85%, a specificity of 75%, and an accuracy of 83% for reader 1 for the detection of a tear of the TFCC. In the same patient population, 3.0T wrist MRI had a sensitivity of 94%, a specificity of 88%, and an accuracy of 91% for reader 1. For reader 2, the improvement in sensitivity for the lunotriquetral ligament between the 1.5T and 3.0T images was statistically significant. The sensitivity, specificity, and accuracy of 3.0T wrist MRI for the TFCC is consistently higher compared with those of 1.5T wrist MRI. The trend suggests that 3.0T wrist MRI provides improved capability for detection of TFCC injuries. Given the available sample size, however, the confidence intervals around the point estimates are wide and overlapping. Further studies are needed to confirm or refute our results of the estimated sensitivity, specificity, and accuracy parameters.