Sagittal T2-weighted Fast Spin Echo Research Articles

Fast high-quality MRI protocol of the lumbar spine with deep learning-based algorithm: an image quality and scanning time comparison with standard protocol

ObjectiveThe objective of this study is to prospectively compare quantitative and subjective image quality, scanning time, and diagnostic confidence between a new deep learning-based reconstruction(DLR) algorithm and standard MRI protocol of lumbar spine.Materials and methodsEighty healthy volunteers underwent 1.5T MRI examination of lumbar spine from September 2021 to May 2023. Protocol acquisition comprised sagittal T1- and T2-weighted fast spin echo and short-tau inversion recovery images and axial multislices T2-weighted fast spin echo images. All sequences were acquired with both DLR algorithm and standard protocols. Two radiologists, blinded to the reconstruction technique, performed quantitative and qualitative image quality analysis in consensus reading; diagnostic confidence was also assessed. Quantitative image quality analysis was assessed by calculating signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Qualitative image quality analysis and diagnostic confidence were assessed with a five-point Likert scale. Scanning times were also compared.ResultsDLR SNR was higher in all sequences (all p<0.001). CNR of the DLR was superior to conventional dataset only for axial and sagittal T2-weighted fast spin echo images (p<0.001). Qualitative analysis showed DLR had higher overall quality in all sequences (all p<0.001), with an inter-rater agreement of 0.83 (0.78–0.86).DLR total protocol scanning time was lower compared to standard protocol (6:26 vs 12:59 min, p<0.001).Diagnostic confidence for DLR algorithm was not inferior to standard protocol.ConclusionDLR applied to 1.5T MRI is a feasible method for lumbar spine imaging providing morphologic sequences with higher image quality and similar diagnostic confidence compared with standard protocol, enabling a remarkable time saving (up to 50%).

A Deep Learning Pipeline Using Prior Knowledge for Automatic Evaluation of Placenta Accreta Spectrum Disorders With MRI.

The diagnosis of prenatal placenta accreta spectrum (PAS) with magnetic resonance imaging (MRI) is highly dependent on radiologists' experience. A deep learning (DL) method using the prior knowledge that PAS-related signs are generally found along the utero-placental borderline (UPB) may help radiologists, especially those with less experience, to mitigate this issue. To develop a DL tool for antenatal diagnosis of PAS using T2-weighted MR images. Retrospective. Five hundred and forty pregnant women with clinically suspected PAS disorders from two institutions, divided into training (409), internal test (103), and external test (28) datasets. Sagittal T2-weighted fast spin echo sequence at 1.5 T and 3 T. An nnU-Net was trained for placenta segmentation. The UPB straightening approach was used to extract the utero-placental boundary region. The UPB image was then fed into DenseNet-PAS for PAS diagnosis. DenseNet-PP learnt placental position information to improve the PAS diagnosis performance. Three radiologists with 8, 10, and 12 years of experience independently evaluated the images. Two radiologists marked the placenta tissue. Histopathological findings were the reference standard. Area under the curve (AUC) was used to evaluate the classification. Dice coefficient evaluated the segmentation between radiologists and the model performance. The Mann-Whitney U-test or the chi-squared test assessed the significance of differences. Decision curve analysis was used to determine clinical effectiveness. DeLong's test was used to compare AUCs. Of the 540 patients, 170 had PAS disorders confirmed by histopathology. The DL model using UPB images and placental position yielded the highest AUC of 0.860 and 0.897 in internal test and external test cohorts, respectively, significantly exceeding the performance of three radiologists (internal test AUC, 0.737-0.770). By extracting the UPB image, this fully automatic DL pipeline achieved high accuracy and may assist radiologists in PAS diagnosis using MRI. 3 TECHNICAL EFFICACY: Stage 2.

Cine magnetic resonance imaging of the uterus for evaluation of abnormal uterine bleeding

To assess the potential role of cine magnetic resonance imaging (MRI) in the evaluation of uterine peristalsis in women classified with abnormal uterine bleeding - endometrial (AUB-E) by measuring frequency and directionality of waveforms. This was a prospective pilot study of seven women with normal menses and eight women with AUB-E, defined as regular but excessive flow causing anemia or interfering with daily activities. Exclusion criteria included other causes of AUB in the PALM-COEIN system. Subjects were evaluated using a modified Menstrual Impact Questionnaire (MIQ). MRI studies were performed within days 1-5 of the subject's menstrual cycle using a 3.0T MRI and 8-channel cardiac phased array coil. Axial and sagittal T2-weighted fast spin echo was obtained to evaluate uterine morphology. Cine MRI imaging was performed using a single shot fast spin echo with a temporal resolution of 2 to 3 seconds over a 2 minutes sequence to evaluate frequency and directionality of uterine waveforms, repeated 2-3 times, and maximum number of waveforms per two minutes reported. Images were reviewed independently by two expert radiologists blinded to patients’ histories. Primary outcome was peristaltic frequency of the subendometrium measured as number of waveforms per two minutes. Secondary outcome was directionality. Primary outcome and MRI morphology were compared by Mann-Whitney U test. MIQ responses were compared by Fischer’s exact test and Mann-Whitney U test. Normal subjects bled an average of 3.9 days and those with AUB-E bled an average of 6.4 days (p= 0.016). Normal subjects defined their flow as light or moderate. Six of seven normal subjects reported no impact on their work, physical or social activity. In comparison, all but one subject with AUB-E defined their flow as heavy or very heavy with passage of clots or flooding (p = 0.001). All subjects with AUB-E reported effect on their daily activities (p < 0.001) and were more likely to report effect on their social activity (p < 0.001) and physical activity (p < 0.001). Subjects with AUB-E were more likely to report dysmenorrhea (p=0.041). Thirteen of fifteen women demonstrated motility of the subendometrium during cine display. Two women with AUB-E did not demonstrate waveforms. There was complete agreement between readers with regard to maximum number of waveforms per two minute cycle and directionality. Median number of waveforms in subjects with normal menses was 3 per two minutes. In patients with AUB-E, the median number of waveforms was 1 per two minutes (p=0.009). All subjects with waveforms exhibited cervico-fundal directionality during menses. Cine MRI is a feasible modality for measuring differences in the frequency of uterine peristalsis in women with AUB-E. This pilot study supports further investigation into the endometrial and myometrial contributions to abnormal bleeding in women with AUB-E.

Detection of multiple sclerosis lesions in the cervical cord: which of the MAGNIMS 'mandatory' non-gadolinium enhanced sagittal sequences is optimal at 3T?

The magnetic resonance imaging in multiple sclerosis consensus guidelines currently mandate three sagittal non-contrast enhanced sequences of T2-weighted fast spin echo, proton density-weighted fast spin echo and short tau inversion recovery; however, these particular three sequences have not previously been compared at 3T. This study compared T2-weighted fast spin echo, proton density-weighted fast spin echo, short tau inversion recovery as well as the double inversion recovery sequence for the sagittal detection of multiple sclerosis lesions in the cervical spinal cord at 3T. Nineteen multiple sclerosis patients underwent magnetic resonance imaging with 3T sagittal T2-weighted fast spin echo, proton density-weighted fast spin echo, short tau inversion recovery and double inversion recovery between November 2012 and April 2013. Two neuroradiologists independently reviewed the images, and the number of lesions detected on each sequence was recorded. Lesion conspicuity was quantitatively assessed with the lesion-to-cord-contrast ratio and lesion contrast-to-noise ratio. The Wilcoxon signed rank test was performed for statistical analysis. Proton density-weighted fast spin echo and short tau inversion recovery detected 32% more lesions compared to T2-weighted fast spin echo, and 37% more lesions compared to double inversion recovery. The lesion-to-cord-contrast ratio was highest in short tau inversion recovery, while the lesion contrast-to-noise ratio was highest for proton density-weighted fast spin echo. This study provides the necessary evidentiary support at 3T for the magnetic resonance imaging in multiple sclerosis spinal magnetic resonance imaging protocol consensus guidelines. At 3T sagittal proton density-weighted fast spin echo and short tau inversion recovery sequences allowed improved detection of cervical spinal cord multiple sclerosis lesions, compared to T2-weighted fast spin echo and three-dimensional double inversion recovery magnetic resonance imaging. Utilising T2-weighted fast spin echo alone at 3T is insufficient for lesion detection.

Combining ACL Oblique Coronal MRI with the Routine Knee MRI Protocol in the Diagnosis of ACL Bundle Lesions. Can It Add A Value?

Abstract Background: The Anterior Cruciate Ligament (ACL) is formed of two bundles. Routine MRI protocol is usually insufficient to delineate both bundles structure, so diagnosis of AM and PL bundle injury is often limited, and development of further imaging orientation and pulse sequences is key for further improving characterization of these bundles. Accurately grading the ACL tears and differentiating between complete and partial tears as well as assessing the two bundles is key in improving the clinical and surgical management. Aim of Study: The purpose of this study is to evaluate the diagnostic value of combining oblique coronal images to the routine MRI protocol for better assessment of the ACL bundles, thus improving management outcome by performing two MRI protocols and comparing them to the arthroscopic findings. Patients and Methods: This prospective study was con-ducted between January 2016 and February 2018 in Ain Shams University Hospitals and private centers. The study population has consisted of 32 patients (26 men & 6 women), ranging between 19-45 years, with mean age of 27.11 years. All patients were suspected of ACL injury referred from the outpatient clinic of orthopedic. All patients were examined by MRI examinations com-posed of sagittal T2-weighted Fast-Spin Echo (FSE), coronal T2-weighted FSE, and axial T2-weighted. The sagittal images were planned on axial localizer by 15-degree medial angling on perpendicular line to the bicondylar line and by oblique coronal MRI were the oblique coronal STIR images named were planned on midsagittal localizer in the plane parallel to the ACL and the roof of the intercondylar notch (Blumensaat's line). A consultant orthopedic surgeon did a diagnostic arthros-copy for all included patients using standard parapatellar portals visualizing the ACL with direct visualizing of both bundles and accordingly classifying each bundle as torn or intact. Results: The Oblique coronal MRI showed a better agree-ment with the diagnostic arthroscopy than routine MRI [weight-ed Kappa; k=0.865 & 0.753 respectively]. For diagnosis of Anteromedial Bundle (AMB) tear the sensitivity was 90.9%, specificity 80%, with overall accuracy of 87.5%. For diagnosis of Posterolateral Bundle (PLB) tear. The sensitivity was 95.5%, specificity 90%, with overall accuracy of 93.8%. Conclusion: The adding of oblique coronal imaging to routine MRI protocol revealed better delineation of the ACL bundles, increasing the accuracy of diagnosis each or both bundle lesions, providing significant benefit in further man-agement and outcome in patient with suspected ACL injury.

SINGLE-SHOT TURBO SPIN ECHO PULSE SEQUENCE FINDINGS IN DOGS WITH AND WITHOUT PROGRESSIVE MYELOMALACIA.

Progressive myelomalacia is an uncommon type of ischemic, hemorrhagic spinal cord infarction. Diagnosis can be difficult, but prompt recognition is important. We hypothesized that cerebrospinal fluid signal attenuation on magnetic resonance (MR) images would be more extensive in dogs that developed progressive myelomalacia vs. control dogs. A retrospective analytic cohort study was designed. Dogs were included if they presented for acute paraplegia and loss of deep pain perception and had undergone MR imaging using both sagittal single-shot turbo spin echo (SSTSE) and standard sagittal T2-weighted fast spin echo (T2W) pulse sequences. Dogs were divided into progressive myelomalacia and control groups for comparisons. All MR examinations were evaluated by three reviewers blinded to patient outcome. Length of cerebrospinal fluid attenuation was recorded as a ratio to the length of the L2 vertebral body in SSTSE and T2W sequences (CSF:L2SSTSE and CSF:L2T2 , respectively). Length of intramedullary spinal cord hyperintensity was recorded as a ratio to the length of the L2 vertebral body in T2W sequences. A total of 21 dogs were included (five in the progressive myelomalacia group and 16 in the control group). The mean CSF:L2SSTSE attenuation value was significantly higher in dogs that developed progressive myelomalacia (CSF:L2SSTSE = 10.7) compared to controls (CSF:L2SSTSE = 5.4; P = 0.015). A cut off ratio of attenuation >7.4 provided optimal differentiation between groups in this study. Findings supported the conclusion that dogs with CSF:L2SSTSE ≤ 7.4 are unlikely to develop progressive myelomalacia while dogs with CSF:L2SSTSE > 7.4 are indeterminate for progressive myelomalacia.

T1rho MRI relaxation in knee OA subjects with varying sizes of cartilage lesions

BackgroundThe purpose of this investigation is to evaluate the T1ρ relaxation times of articular cartilage surrounding focal defects in the tibiofemoral joint. MethodsQuantitative cartilage assessment was performed using 3T MRI with T1ρ mapping in 19 healthy individuals and 44 OA patients. Sagittal T2-weighted fast spin echo (FSE) images were acquired for lesion assessment. Differences were determined using analysis of variance (ANOVA). ResultsCartilage lesions were found in 37% of controls, and 93% of OA patients. Meniscal tears were found in 16% of controls and 57% of OA patients. We observed no difference in T1ρ relaxation times when comparing cartilage immediately surrounding a focal defect, and the remaining cartilage within that compartment. The medial femoral condyle (MFC) had the highest incidence of cartilage defects. MFC and medial meniscus posterior horn T1ρ were higher in subjects having multiple focal lesions (p=0.048, pb0.001 respectively) and extensive full thickness lesions (p=0.009, pb0.001 respectively) compared to subjects with no MFC defects. Significant elevations in T1ρ of the adjacent compartment (medial tibia) and medial meniscus were observed in subjects with MFC lesions. ConclusionIncreased relaxation times in the involved compartment as well as the adjacent compartment and associated meniscus underscore the interdependence of these structures at bearing load. However, no differences in cartilage composition immediately surrounding a defect were noted. Finally, an association was observed between cartilage defects and meniscal damage in advanced disease. Clinical RelevanceCartilage defects were not associated with degeneration in the immediately adjacent cartilage.

Ligaments and Plicae of the Elbow: Normal MR Imaging Variability in 60 Asymptomatic Subjects

To prospectively evaluate the normal variability of ligaments, plicae, and the posterior capitellum on conventional magnetic resonance (MR) images of the elbow in asymptomatic volunteers. The study was approved by the institutional ethics board, and informed consent was obtained from all subjects. MR imaging was performed at 1.5 T in 60 asymptomatic volunteers (30 women, 30 men; age range, 22-51 years; median age, 32.8 years) by using the following five pulse sequences: transverse T1-weighted spin-echo, sagittal T2-weighted fast spin-echo, coronal fast spin-echo short-inversion-time inversion recovery, transverse intermediate-weighted with fat saturation, and coronal three-dimensional water-excitation true fast imaging with steady-state precession. The visibility (completely visible over the entire course, partially visible, or not visible) and signal intensity characteristics (hypointense or hyperintense to muscle, homogeneous signal intensity vs striation) of the elbow ligaments and plicae were evaluated by three independent readers. The presence of pseudodefects at the posterior capitellum was determined. The dimensions of all structures were measured by two independent readers. The anterior ulnar collateral ligament (UCL) and radial collateral ligament (RCL) were visible over their entire course in all 60 subjects (100%). The posterior UCL, lateral UCL, and annular ligament (AL) were completely visible in 58 (97%), 51 (85%), and 59 (98%) of the 60 subjects, respectively, and partially visible in the remaining subjects. Increased signal intensity with fluid-sensitive sequences was found in the anterior UCL in nine of the 60 subjects (15%), posterior UCL in four subjects (7%), RCL in one subject (2%), lateral UCL in six subjects (10%), and AL in one subject (2%). The median thickness and 90th percentile were 2.5 and 3.5 mm, respectively, for the anterior UCL, 1.0 and 1.7 mm for the posterior UCL, 1.9 and 2.8 mm for the RCL, 2.3 and 3.8 mm for the lateral UCL, and 1.0 and 1.3 mm for the AL. A posterolateral plica (median dimension, 4.3 × 1.9 × 3.9 mm) was found in 59 of the 60 subjects (98%), whereas a posterior plica (median dimension, 1.8 × 1.4 mm) could be detected in only 20 (33%). A pseudodefect of the capitellum was noted in 51 of the 60 subjects (85%). The elbow ligaments and the posterolateral plica are consistently visible on conventional MR images of asymptomatic subjects. Most normal ligaments are thinner than 4 mm, and most plicae are thinner than 3 mm.

Temporal assessment of bone marrow lesions on magnetic resonance imaging in a canine model of knee osteoarthritis: impact of sequence selection

To assess the evolution of bone marrow lesions (BMLs) in a canine model of knee osteoarthritis (OA) using three different magnetic resonance imaging (MRI) sequences. Three MRI sequences [coronal, T1-weighted three-dimensional fast gradient recalled echo (T1-GRE), sagittal fat-suppressed 3D spoiled gradient echo at a steady state (SPGR), and sagittal T2-weighted fast spin echo with fat saturation (T2-FS)] were performed at baseline, and at week 4, 8 and 26 in five dogs following transection of the anterior cruciate ligament. The same reader scored (0-3) subchondral BMLs twice, in blinded conditions, according to their extent in nine joint subregions, for all imaging sessions, and independently on the three MRI sequences. Correlation coefficients and Bland-Altman plots evaluated intra-reader repeatability. Readings scores were averaged and the nine subregions were summed to generate global BML scores. BMLs were most prevalent in the central and medial portions of the tibial plateau. Intra-reader repeatability was good to excellent for each sequence (r(s)=0.87-0.97; P<0.001). Maximal intra-reader variability (24%) was reached on T2-FS and was associated to higher scores (P<0.05). Global BML scores increased similarly on all three sequences until week 8 (P<0.05). At week 26, score on T2-FS was decreased, being lower when compared to T1-GRE and SPGR (P<0.05). In this canine OA model, the extent of BMLs varies in time on different MRI sequences. Until the complex nature of these lesions is fully resolved, it is suggested that to accurately assess the size and extent of BMLs, a combination of different sequences should be used.

Prevalence of annular tears and disc herniations on MR images of the cervical spine in symptom free volunteers

Study design: Prospective MR analysis of the cervical spine of 30 asymptomatic volunteers. Objectives: To evaluate the prevalence of annular tears, bulging discs, disc herniations and medullary compression on T2-weighted and gadolinium-enhanced T1-weighted magnetic resonance (MR) images of the cervical spine in symptom free volunteers. Summary of background data: Few studies have reported the prevalence of cervical disc herniations in asymptomatic people, none have reported the prevalence of cervical annular tears on MR images of symptom free volunteers. Materials and methods: Thirty symptom-free volunteers (no history or symptoms related to the cervical spine) were examined using sagittal T2-weighted fast spin-echo (SE), sagittal gadolinium-enhanced T1-weighted SE imaging and axial T2 *-weighted gradient echo (GRE). The prevalence of bulging discs, focal protrusions, extrusions, nonenhancing or enhancing annular tears and medullary compression were assessed. Results: The prevalence of bulging disk and focal disk protrusions was 73% (22 volunteers) and 50% (15 volunteers), respectively. There was one extrusion (3%). Eleven volunteers had annular tears at one or more levels (37%) and 94% of the annular tears enhanced after contrast injection. Asymptomatic medullary compression was found in four patients (13%). Conclusion: Annular tears and focal disk protrusions are frequently found on MR imaging of the cervical spine, with or without contrast enhancement, in asymptomatic population. The extruded disk herniation and medullary compression are unusual findings in a symptom-free population.

Three-dimensional 1H-magnetic resonance spectroscopy of the prostate in clinical practice: technique and results in patients with elevated prostate-specific antigen and negative or no previous prostate biopsies

To assess the benefit of routinely used three-dimensional 1H-spectroscopy of the prostate combined with magnetic resonance imaging in patients with elevated prostate-specific antigen (PSA) levels and negative or no previous prostate biopsies. Fifty-four patients were examined with our combined imaging protocol, which consisted of transversal, coronal and sagittal T2-weighted fast spin echo sequences. For spectroscopy, we used a three-dimensional chemical shift imaging spin echo (3D-CSI-SE) sequence. The study population consisted of patients with elevated PSA levels and histologically proven prostate carcinoma and patients with elevated PSA levels and negative or no previous prostate biopsies. Examination time was 31 min, a time feasible for routine use. Eighty-eight tumour voxels and 67 control voxels of 27 patients with histologically proven prostate carcinoma were analysed. Ratios of (choline + creatine)/citrate [(Cho + Crea)/Cit] below 0.6 were classified as normal and above 0.6 as pathological. Applying this classification to 20 patients with tumour-suspicious lesions of the prostate and negative or no previous prostate biopsies, we could obtain a sensitivity and specificity for tumour detection of 100% and 69%, respectively. Our combined imaging protocol is feasible for routine use and can add valuable information for the diagnostic management of patients with negative or no previous prostate biopsies.

Magnetic resonance imaging in the diagnosis of benign and malignant pelvic tumors

Magnetic resonance imaging (MRI) is an accepted imaging method for diagnosing diseases of the female pelvis. This review article describes the role of MR imaging for the diagnosis of benign and malignant pelvic tumors. Sagittal T2-weighted fast spin echo sequences can be effectively applied to diagnose leiomyomas of the uterus and provide exact pretreatment measurements of size and localization. In the diagnostic work-up of endometrial carcinoma, fat-saturated, T1-weighted gradient echo sequences make it possible to determine precisely how deep myometrial infiltration extends and what tissue should be included in preoperative treatment planning. In cervical cancer staging, MRI permits both assessment of local tumor extent and determination of tumor volume for planning and monitoring radiotherapy. The usefulness of MRI in cervical cancer staging is, however, limited since not all early-stage cancer (FIGO stage IA and small stage IB tumors) can be detected. Hence, it appears that the use of MRI as a screening method for cervical cancer cannot be recommended. MRI can distinguish between benign and malignant ovarian tumors with high sensitivity and specificity. Standard and fat-saturated T1-weighted sequences usually can diagnose teratomas with a specificity of 100 %. Axial fat-saturated, contrast enhanced T1-weighted spin echo sequences are useful in the staging of malignant ovarian tumors since they facilitate evaluation of their internal structure and will disclose peritoneal metastases. Besides staging of ovarian cancer, MRI can be applied for localization and for monitoring treatment response.

Articular Cartilage of Knee: Normal Patterns at MR Imaging That Mimic Disease in Healthy Subjects and Patients with Osteoarthritis

To evaluate normal magnetic resonance (MR) imaging findings that may mimic articular cartilage diseases in healthy subjects and patients with osteoarthritis of the knee. Sagittal fat-suppressed intermediate-weighted fast spin-echo (FSE) (repetition time msec/echo time [TE] msec, 4,000/13), sagittal T2-weighted FSE (4,000/39), and sagittal fat-suppressed three-dimensional (3D) spoiled gradient-echo (SPGR) (60/5, 40 degrees flip angle) MR images were acquired in 28 patients and four volunteers. FSE images with a TE of 13 msec were considered "short-TE images"; those with a TE of 39 msec were considered "long-TE images." Presence of normal MR imaging appearance of articular cartilage was determined by one author. Contrast between cartilage and adjacent structures (meniscus, joint capsule, synovial fluid, muscle) was calculated in posterior regions of the femoral condyle on images obtained with each sequence; Wilcoxon signed rank testing was performed. The following appearances were observed in patients with knee osteoarthritis (on short-TE FSE, long-TE FSE, and SPGR MR images, respectively): (a) ambiguity of surface contour in posterior region of the femoral condylar cartilage (in zero, zero, and 20 patients), (b) linear area of high signal intensity in deep zone adjacent to subchondral bone of femoral condyle (in zero, zero, and 26 patients), (c) pseudolaminar appearance in posterior region of femoral condylar cartilage (in seven, nine, and 24 patients), (d) truncation artifact in patellofemoral compartment (in seven, six, and 27 patients), (e) susceptibility artifact on cartilage surface caused by air or metal (in three, three, and 11 patients), (f) decreased signal intensity in distal part of trochlear cartilage (in 28, 28, and 28 patients), (g) cartilage thinning adjacent to the anterior horn of the lateral meniscus (in 19, 19, and 21 patients), and (h) focal cartilage flattening in posterior region of femoral condyle (in 16, 16, and nine patients). Cartilage-meniscus and cartilage-synovial fluid contrast was significantly higher on fat-suppressed FSE than on fat-suppressed 3D SPGR MR images (P <.001). Fat-suppressed FSE and 3D SPGR MR images showed nonuniform signal intensity arising from articular cartilage and cartilage thinning, both of which could mimic disease.

Breast augmentation and reconstructive surgery: MR imaging of implant rupture and malignancy.

The purpose of this study was to assess the diagnostic accuracy of MRI in detecting prosthesis integrity and malignancy after breast augmentation and reconstruction. Forty-one implants in 25 patients were analyzed by MRI before surgical removal. Imaging results were compared with ex vivo findings. Magnetic resonance imaging of the breast was performed on a 1.5-T system using a dedicated surface breast coil. Axial and sagittal T2-weighted fast spin-echo as well as dynamic contrast-enhanced T1-weighted gradient-recalled-echo sequences were acquired. The linguine sign indicating collapse of the silicone shell or siliconomas indicating free silicone proved implant rupture, whereas early focal contrast enhancement of a lesion was suspicious for malignancy. The sensitivity for detection of implant rupture was 86.7% with a specificity of 88.5%. The positive and negative predictive values were 81.3 and 92.0%, respectively. The linguine sign as a predictor of intracapsular implant rupture had a sensitivity of 80% with a specificity of 96.2%. Magnetic resonance imaging revealed two lesions with suspicious contrast enhancement (one carcinoma, one extra-abdominal fibromatosis). Magnetic resonance imaging is a reliable and reproducible technique for diagnosing both implant rupture and malignant lesions in women after breast augmentation and reconstruction.

To move or not to move: measurements of prostate motion by urethrography using MRI

Purpose: Urethrography is commonly used to aid in definition of the prostate apex during CT simulation for prostate cancer. If the position of the prostate were altered by the urethrogram itself, then systematic error could be introduced into the patient’s treatment. Sagittal MRI scans were acquired immediately before and after a localization urethrogram to determine the extent of displacement. Methods and Materials: Thirteen patients underwent sagittal T2-weighted fast spin echo MRI scans. Patients were scanned supine in an alpha cradle cast in the treatment position. The prostate was contoured by 3 different observers to determine the apex location on the central sagittal MRI section and the center of mass relative to an immobile bony landmark. Statistical multivariate analysis was performed to establish if there was a net displacement of the prostate (systematic error), and to determine the margin required to cover the random prostate position within a 95% confidence interval. Results: There was no significant systematic motion of either the prostate nor its apex in either the anterior–posterior or superior–inferior directions. The average motion of the prostate center of mass was 0.04 ± 0.40 cm (1 SD) and 0.01 ± 0.33 cm in the anterior–posterior and superior–inferior direction, respectively. The corresponding figures for location of the apex were 0.05 ± 0.30 cm and 0.01 ± 0.33 cm, respectively. The statistical analysis revealed that a margin of 2 mm is sufficient to cover any random motion of the prostate that could occur as a result of the urethrogram 95% of the time. Conclusion: Urethrography during CT simulation for prostate cancer does not cause significant prostate displacement or systematic error in planning and delivering external-beam radiation.

Perioperative prediction by MRI of prostate volume six to twelve months after laser-induced thermotherapy of benign prostatic hyperplasia.

The purpose of this study was to predict prostate volume outcome 6-12 months after interstitial, laser-induced thermotherapy (LITT) for benign prostatic hyperplasia (BPH) on the basis of prostate magnetic resonance (MR) images obtained within 48 hours before and after LITT. Twenty patients (age, 64.2 +/- 7.4 years) with symptomatic BPH had LITT of the transitional zone of the prostate. MRI was performed within 48 hours before and after LITT, and 6-12 months after LITT (late follow-up). MRI included axial and sagittal T2-weighted fast spin-echo (FSE) images and contrast-enhanced, axial T1-weighted images. Volumes of different prostatic compartments (total prostate, transitional zone, peripheral zone, LITT lesions) were measured by planimetry. Subtraction of LITT lesion volume less than 48 hours after LITT from total and transitional zone volume before LITT, respectively, predicted respective prostatic volumes at late follow-up. Pearson correlations of predicted and measured total prostate and transitional zone volumes were 0.972 and 0.975, respectively. Total prostate volume at late follow-up was accurately predicted (difference, -0.5 +/- 5.7 cc; P = 0.6981, two-tailed paired t-test). Transitional zone volume was underestimated (difference, -3.1 +/- 4.7 cc; P = 0.0075). Peripheral zone volume was overestimated (difference, 2.6 +/- 3.5 cc; P = 0.0034). Perioperative MRI allows accurate prediction of prostate volume 6-12 months after LITT for BPH. Underestimation of transitional zone volume may be due to ongoing growth of BPH. LITT appears to affect peripheral zone tissue outside the target region. J. Magn. Reson. Imaging 2001;13:64-68.

MR Appearance of Metastatic Melanotic Melanoma in the Breast: Case Reports

A 34-year-old Chinese woman complaining of multiple breast lumps was referred to a local Breast Clinic. She had malignant melanoma of the left middle finger and amputation had been performed 3 months earlier. Fine needle aspiration was performed on two of the breast lumps and they were diagnosed as melanotic melanoma. The pleomorphic malignant cells were immunoreactive for S100 protein and HMB 45. Ultrasound (US) was later performed which showed more than five well circumscribed hypoechoic masses, ranging in size from 0.5 to 1.5 cm, in both breasts. Mammography was performed, which showed three medium density well circumscribed masses in the right breast. There was no axillary adenopathy. Magnetic resonance imaging (MRI) of both breasts was performed with a 1.5T superconductive MR imager (Signa Advantage, GE Medical Systems, Milwaukee, U.S.A.) and a bilateral phased array breast coil. Pre-contrast medium axial T1-weighted spin-echo (TR/TE 1⁄4 500/12) with fat saturation and sagittal T2-weighted fast spin-echo (TR/TE 1⁄4 3440/126, ETL 1⁄4 12) images were acquired with 4 mm thick sections, 1 mm gap, a 256 × 192 matrix and two excitations. After intravenous administration of gadopentetate dimeglumine (0.2 mmol/kg), fat-suppressed axial T1-weighted spinecho images were taken. There were more than five abnormal masses in both breasts, ranging in size from 0.5 to 1.5 cm. The masses yielded high signal on T1-weighted (Fig. 1), low signal on T2-weighted (Fig. 2) and showed decreased signal intensity after contrast medium injection (Fig. 3). In the clinical work-up, there was no evidence of other metastases. Bilateral mastectomy was performed. A specimen photograph was taken (Fig. 4) and MRI was performed (Fig. 5). The patient was followed-up in the Breast Clinic.

Case of the season

A THIRTY-FIVE-YEAR-OLD woman presented with a 3-month history of progressive dysesthesia of her feet, unsteadiness in the gait, and generalized weakness. There was no history of any surgery or drug intake. On examination, there was moderate pallor. Fine touch, position, and vibration sense were impaired below the anterior superior iliac spines. Romberg's sign was positive. There was mildly reduced motor power (4/5) in both lower limbs. Deep tendon reflexes of lower limbs were exaggerated. Plantars were equivocal. Laboratory tests revealed macrocytic anemia with hemoglobin of 8.6 g/dL, elevated mean corpuscular volume (117 fl), hypersegmented neutrophils, low serum cobalamin (<100 pg/mL), and elevated serum folate levels (22 ng/mL). Magnetic resonance imaging (MRI) of the spine was performed. Figure 1 is a sagittal T2-weighted fast spin-echo (FSE) image showing an abnormal increased signal intensity of the dorsal and lower cervical spinal cord. Figure 2 is an axial T2weighted FSE image at the upper dorsal region showing that the signal abnormality is located in the posterior columns of the spinal cord. Barium meal gastrointestinal series was normal.