Fat-suppressed T2-weighted Images Research Articles

Intraosseous leiomyosarcoma arising in the epiphysis of the distal femur

Herein, we present a rare case of intraosseous leiomyosarcoma arising in the epiphysis of the distal femur and showing unusual radiographic features. A 44-year-old man presented with a pain in the left knee joint. Computed tomography revealed an intraosseous lesion with slightly increased attenuation and a thin marginal sclerotic rim in the femoral medial condyle. The signal of the lesion was hypointense on T1-weighted magnetic resonance (MR) images and hyperintense on fat-suppressed T2-weighted MR images. After gadolinium administration, the signal of the lesion was moderately and diffusely enhanced. The histological diagnosis of leiomyosarcoma was made based on a preoperative core biopsy specimen. Microscopic examination of the resected specimen revealed an ill-defined intraosseous tumor composed of proliferated atypical and mildly pleomorphic smooth muscle cells permeating among the bone trabeculae with only focal destruction of the bone trabeculae and low mitotic activity, indicating low grade leiomyosarcoma. The bone trabeculae at the periphery of the tumor were mildly thickened and anastomosed with a rim of an increased number of osteoblasts. Systemic examination showed no tumorous lesions in other anatomical sites. Leiomyosarcomas rarely present in the bone as a diffuse intertrabecular growth, even in low grade tumors.

Case 198

Case 198

1.5-T Magnetic Resonance–Guided Transgluteal Biopsies of the Prostate in Patients With Clinically Suspected Prostate Cancer

The aim of this study was to examine the feasibility and safety of magnetic resonance-guided prostate biopsy (MRGBx) with a transgluteal approach in patients with cancer suspicious prostatic lesions. This study was approved by the ethical committee. A total of 25 men with clinically suspected prostate cancer with increased prostate-specific antigen levels and at least 1 previous negative transrectal ultrasound-guided prostatic biopsy (TRUSBx) underwent diagnostic magnetic resonance (MR) imaging of the prostate. Cancer suspicious regions (CSR) were identified, and MRGBx with a transgluteal approach in a large closed-bore 1.5-T MR system was manually performed in coaxial technique, using transversal fat-suppressed T2-weighted true fast imaging with steady-state free precession sequences. Success rate, biopsy findings, side effects, procedure time, number of acquisitions for the repositioning of the needle guide, and length of the biopsy channel were documented. Follow-up was performed 24 months after the procedure. In diagnostic MR imaging of the prostate, a total of 40 CSRs were detected in 25 patients. All MRGBx procedures were technically successful and all CSRs were biopsied. The mean number of core biopsies per CSR was 3.3 ± 1.5 (range, 1-7). Histopathological analysis revealed adenocarcinoma in 35% (14/40), acute or chronic prostatitis in 30% (12/40), adenofibromyomatous changes in 22.5% (9/40), and no identifiable pathology in 17.5% (7/40) of CSRs, with a pathological overlap for chronic prostatitis and adenofibromyomatous changes in 1 patient with biopsies in 2 CSRs. No missed prostate cancer after MR-guided biopsy in clinical follow-up was detected. Mean procedure time was 31 ± 7 minutes (range, 21-46 minutes). Side effects were hematuria (n = 7), hematospermia (n = 3), combined hematuria/hematospermia (n = 2), and infection (n=1). Magnetic resonance-guided prostate biopsy of the prostate gland with a transgluteal approach is feasible, safe, and a promising technique for histological clarification of cancer suspicious lesions in patients with increased prostate-specific antigen levels after negative TRUSBx. Magnetic resonance-guided prostate biopsy offers a reasonable alternative to repeated TRUSBx for histological clarification of prostate cancer.

Comparison of magnetic resonance enterography, capsule endoscopy and gastrointestinal radiography of children with small bowel Crohn’s disease

The aim of this study was to compare magnetic resonance enterography (MRE) findings with those of video capsule endoscopy (VCE) or conventional gastrointestinal radiography (CGR) in pediatric patients with small bowel Crohn’s disease. A total of 55 cases of small bowel Crohn’s disease that were diagnosed through clinical, laboratory, surgical and histopathological findings were reviewed. Prior to the examination, children suspected of having other types of diseases of the small intestinal were identified. The pulse sequences included coronal T2-true-fast imaging with steady-state precession (TrueFISP) images, navigation axial and coronal T1-weighted images, T2-weighted fat-suppressed images and coronal fat-suppressed three-dimensional gradient-echo images, immediately followed by contrast-enhanced axial and coronal T1-weighted fat-suppressed images. Findings from MRE were compared with those of VCE (n=39) and CGR (n=37). MRE results exhibited a number of features characteristic to small bowel Crohn’s disease, including wall thickening, mesenteric fibrofatty changes and mesenteric vasculature changes. VCE, MRE and CGR demonstrated sensitivities of 94.6, 85.7 and 71.1% with specificities of 72.7, 70 and 40%; accuracies of 89.6, 82.2 and 61.1%; positive predictive values of 92.1, 90.9 and 59.6%; and negative predictive values of 80, 58.3 and 40%, respectively. VCE depicted mucosal pathologies missed by MRE in three patients. MRE revealed 83 extraenteric findings in 55 patients and CGR was able to show the dynamic evolution of the gastrointestinal function. MRE is a simple, safe, non-invasive and effective method for evaluating small bowel Crohn’s disease. VCE allows visualization and readily characterizes subtle mucosal lesions missed by MRE, whereas MRE yields additional mural, perienteric and extraenteric information. However, oral barium CGR utilizes radiation, which is not suitable for repeated use in children.

Analysis of fatty infiltration and inflammation of the pelvic and thigh muscles in boys with Duchenne muscular dystrophy (DMD): grading of disease involvement on MR imaging and correlation with clinical assessments

Prior reports focus primarily on muscle fatty infiltration in Duchenne muscular dystrophy (DMD). However, the significance of muscle edema is uncertain. To evaluate the frequency and degree of muscle fat and edema, and correlate these with clinical function. Forty-two boys (ages 5-19years) with DMD underwent pelvic MRI. Axial T1- and fat-suppressed T2-weighted images were evaluated to grade muscle fatty infiltration (0-4) and edema (0-3), respectively. Degree and frequency of disease involvement were compared to clinical evaluations. Gluteus maximus had the greatest mean fatty infiltration score, followed by adductor magnus and gluteus medius muscles, and had the most frequent and greatest degree of fatty infiltration. Gluteus maximus also had the greatest mean edema score, followed by vastus lateralis and gluteus medius muscles. These muscles had the most frequent edema, although the greatest degree of edema was seen in other muscles. There was correlation between cumulative scores of fatty infiltration and all clinical evaluations (P < 0.05). In DMD, the muscles with the most frequent fatty infiltration had the greatest degree of fatty infiltration and correlated with patient function. However, the muscles with the most frequent edema were different from those with the greatest degree of edema. Thus, edema may not predict patient functional status.

Accuracy of routine fat-suppressed FLAIR and diffusion-weighted images in detecting clinically evident acute optic neuritis

Background Contrast-enhanced, fat-suppressed T1-weighted imaging (CET1WI) magnetic resonance imaging (MRI) is quite sensitive in detecting acute optic neuritis (ON), but ON remains a clinical diagnosis. MRI is indicated to evaluate demyelinating brain lesions rather than the optic nerves, while “routine” brain protocols typically include axial FLAIR and DWI. Purpose To evaluate the accuracy of axial, fat-suppressed FLAIR and DWI sequences used for our routine brain imaging in detecting acute ON, as compared to CET1WI and the clinical diagnosis. Material and Methods The clinical data and MRI examinations were retrospectively reviewed of 60 patients presenting to a neuro-ophthalmologist for various visual symptoms. Each patient underwent dedicated neuro-ophthalmologic examination, with axial 5 mm fat-suppressed FLAIR and DWI (part of “routine” brain MRI protocol), as well as 3 mm axial and coronal fat-suppressed CET1WI (part of dedicated orbit MRI protocol). Two neuroradiologists independently evaluated FLAIR and DWI, while CET1WI was reviewed by consensus. Results Thirty-one patients were clinically positive, 29 negative for ON (total = 34 positive and 86 negative nerves). The sensitivities of FLAIR, DWI, and CET1WI for ON were 75.7–77.3%, 77.3%, and 89.5%, respectively; the specificities were 90.5–93.5%, 80.4–82.7%, and 86.0%, respectively; the accuracies were 85.7–88.2%, 79.5–81.1%, and 87.0%, respectively. Inter-observer kappa was 0.783 for FLAIR, and 0.605 for DWI; intra-observer kappa was 0.746–0.816 for FLAIR, and 0.674–0.699 for DWI (each P &lt; 0.0001). Conclusion Being more specific, but not as sensitive, as dedicated CET1WI in acute ON, axial fat-suppressed FLAIR likely has additional value in evaluating for acute ON in “routine” brain MR protocols evaluating for demyelinating disease, while DWI may be hampered by artifacts.

Magnetic Resonance Imaging of the Hand and Wrist: Techniques and Spectrum of Disease

Magnetic resonance imaging (MRI) is an excellent imaging modality for the evaluation of pathologic processes of the hand and wrist. MRI of the hand and wrist provides high-resolution imaging of osseous structures and soft-tissue structures (including ligaments, tendons, nerves, and muscles) through the use of multiple imaging techniques and pulse sequences. This article updates orthopaedic surgeons on current MRI techniques and illustrates the spectrum of hand and wrist disease detectable by MRI. We searched PubMed with use of the keywords “MRI” plus “hand” or “wrist” for studies less than five years old evaluating MRI techniques. On the basis of a review of the recently published literature and the authors’ experience, we define and describe the applications of the following: (1) conventional, non-gadolinium-enhanced MRI, (2) gadolinium-enhanced MRI, and (3) MR arthrography. We also describe the classic MRI appearance of lesions commonly evaluated by MRI, including occult fracture, triangular fibrocartilage complex injury, interosseous ligament injury, extrinsic carpal ligament injury, thumb ulnar collateral ligament injury, traumatic tendon injury, finger pulley injury, ulnar impaction syndrome, tendinopathy, Kienbock disease, posttraumatic scaphoid osteonecrosis, infection, inflammatory arthropathy, compression neuropathy, and various soft-tissue masses. The incorporation of dedicated surface coils and higher-strength magnets has improved the quality of magnetic resonance imaging (MRI) scanners substantially over the last decade. By manipulating the scanning parameters when performing an MRI examination, contrast differences between tissues can be emphasized on the basis of inherent tissue properties known as T1 and T2. T1-weighted images are generally regarded as best for illustrating anatomic detail. T2-weighted sequences highlight alterations in water content, which are characteristic of most pathologic conditions. Short tau inversion recovery (STIR) and fat-suppressed T2-weighted images accentuate fluid and edema and are the most sensitive for detecting pathologic changes in both bone and soft tissue. The intravenous administration of a gadolinium-based contrast agent …

Accuracy of routine fat-suppressed FLAIR and diffusion-weighted images in detecting clinically evident acute optic neuritis

Contrast-enhanced, fat-suppressed T1-weighted imaging (CET1WI) magnetic resonance imaging (MRI) is quite sensitive in detecting acute optic neuritis (ON), but ON remains a clinical diagnosis. MRI is indicated to evaluate demyelinating brain lesions rather than the optic nerves, while "routine" brain protocols typically include axial FLAIR and DWI. To evaluate the accuracy of axial, fat-suppressed FLAIR and DWI sequences used for our routine brain imaging in detecting acute ON, as compared to CET1WI and the clinical diagnosis. The clinical data and MRI examinations were retrospectively reviewed of 60 patients presenting to a neuro-ophthalmologist for various visual symptoms. Each patient underwent dedicated neuro-ophthalmologic examination, with axial 5 mm fat-suppressed FLAIR and DWI (part of "routine" brain MRI protocol), as well as 3 mm axial and coronal fat-suppressed CET1WI (part of dedicated orbit MRI protocol). Two neuroradiologists independently evaluated FLAIR and DWI, while CET1WI was reviewed by consensus. Thirty-one patients were clinically positive, 29 negative for ON (total = 34 positive and 86 negative nerves). The sensitivities of FLAIR, DWI, and CET1WI for ON were 75.7-77.3%, 77.3%, and 89.5%, respectively; the specificities were 90.5-93.5%, 80.4-82.7%, and 86.0%, respectively; the accuracies were 85.7-88.2%, 79.5-81.1%, and 87.0%, respectively. Inter-observer kappa was 0.783 for FLAIR, and 0.605 for DWI; intra-observer kappa was 0.746-0.816 for FLAIR, and 0.674-0.699 for DWI (each P < 0.0001). Being more specific, but not as sensitive, as dedicated CET1WI in acute ON, axial fat-suppressed FLAIR likely has additional value in evaluating for acute ON in "routine" brain MR protocols evaluating for demyelinating disease, while DWI may be hampered by artifacts.

Breast cancer subtypes based on ER/PR and Her2 expression: comparison of MR imaging features

To evaluate the magnetic resonance (MR) imaging findings of breast cancer subtypes based on the profiles of ER/PR and Her2. A retrospective study was conducted for 267 breast cancer subjects between February 2007 and January 2011. Clinicopathologic features and MR imaging findings of four subtypes were compared. The Chi-square (χ(2)) test, Fisher's exact test and χ(2) section method were employed for categorical variables. MR imaging findings:Patients with segment or linear enhancement type accounted for 25.6% in ER/PR(+), Her2(+) subtype group and 36.1% in ER/PR(-), Her2(+) subtype, no significant difference existed between them (χ(2) = 1.112, P = 0.641). But they were significantly higher than ER/PR(+), Her2(-) subtype group and ER/PR(-), Her2(-) subtype group (χ(2) = 32.793, P < 0.001; χ(2) = 14.565, P < 0.001). ER/PR(-), Her2(-) subtype patients accounted for 14.6% of the total breast cancer patients (39/267). Subjects with ER/PR(-), Her2(-) subtype were more likely to present unifocal (91.7%, 33/36) and mass type lesion (92.3%, 36/39). The mass type lesions in ER/PR(-), Her2(-) subtype group were more likely to showed smooth margin [58.3% (21/36), P < 0.001], very high intratumoral signal and peripheral hyperintense pattern on fat suppression T2-weighted imaging (P < 0.001) and early rim enhancement [81.5% (29/36), P < 0.001]. No significantly difference of four subtypes were found on number of mass, mass shape and pattern at dynamic enhancement imaging (χ(2) = 1.413, P = 0.713; χ(2) = 8.423, P = 0.204; χ(2) = 4.657, P = 0.540). Segment or linear enhancement type is characterized by MR imaging. Early rim enhanced mass is ER/PR(-), Her2(-) breast cancer. The most important characteristics of MR imaging include a smooth edge of breast mass, very high intratumoral signal on fat suppression T2-weighted imaging and peripheral hyperintense pattern.

Diagnostic value of gadolinium-enhanced dynamic MR imaging for parotid gland tumors

ObjectiveThis study aimed to evaluate the value of gadolinium-enhanced dynamic MR imaging for differentiating benign and malignant parotid gland tumors, and for characterizing the various histological types. Patients and methodsNon-enhanced T1-weighted (T1-W), fat-suppressed T2-weighted (T2-W), and gadolinium-enhanced fat-suppressed dynamic T1-weighted images were obtained preoperatively in 27 patients (28 parotid gland tumors), by using a 1.5 or 3 T MR imaging unit (GE, Signa Exite). The tumor margins and the enhancement curve patterns on dynamic MR imaging were analyzed. All patients underwent a parotidectomy with histopathologic analysis. ResultsPleomorphic adenomas depict a gradual enhancement pattern. Warthin’s tumors depict an early peak of enhancement and a high washout pattern. Malignant tumors depict an early peak of enhancement and a low washout pattern. ConclusionGadolinium-enhanced dynamic MR imaging improved the performance of MR imaging in differentiating benign from malignant parotid gland tumors and characterizing the different histological types of benign tumors.

Muscle MRI in severe Guillain–Barré syndrome with motor nerve inexcitability

We report on the clinical, electrophysiological, and lower-limb musculature MRI findings in a severe demyelinating Guillain-Barré syndrome (GBS) patient with follow-up over 6months. After 3weeks of tetraplegia and mechanical ventilation, there was progressive improvement until almost complete recovery. On day 4 after onset, electrophysiological study revealed absent F waves and widespread conduction block. On four further electrophysiological studies on days 12, 19, 45, and 150, there was marked and reversible slow down of motor conduction velocities in upper-limb nerves, and persistent inexcitability of lower-limb nerves. Mild signs of active denervation were recorded in calf and foot muscles as of day 45. On day 39, MRI T2-weighted fat-suppressed images showed patchy hypersignal of variable intensity involving pelvic, thigh, and calf muscles, which disappeared in a second imaging study on day 190; in this study T1-weighted images did not disclose muscle fatty atrophy. We conclude that in severe demyelinating GBS prolonged motor nerve inexcitability should not necessarily be taken as a predictor of poor prognosis, and that MRI is useful in assessing the topography and evolution of muscle denervation.

A computerized MRI biomarker quantification scheme for a canine model of Duchenne muscular dystrophy

Golden retriever muscular dystrophy (GRMD) is a widely used canine model of Duchenne muscular dystrophy (DMD). Recent studies have shown that magnetic resonance imaging (MRI) can be used to non-invasively detect consistent changes in both DMD and GRMD. In this paper, we propose a semiautomated system to quantify MRI biomarkers of GRMD. Our system was applied to a database of 45 MRI scans from 8 normal and 10 GRMD dogs in a longitudinal natural history study. We first segmented six proximal pelvic limb muscles using a semiautomated full muscle segmentation method. We then performed preprocessing, including intensity inhomogeneity correction, spatial registration of different image sequences, intensity calibration of T2-weighted and T2-weighted fat-suppressed images, and calculation of MRI biomarker maps. Finally, for each of the segmented muscles, we automatically measured MRI biomarkers of muscle volume, intensity statistics over MRI biomarker maps, and statistical image texture features. The muscle volume and the mean intensities in T2 value, fat, and water maps showed group differences between normal and GRMD dogs. For the statistical texture biomarkers, both the histogram and run-length matrix features showed obvious group differences between normal and GRMD dogs. The full muscle segmentation showed significantly less error and variability in the proposed biomarkers when compared to the standard, limited muscle range segmentation. The experimental results demonstrated that this quantification tool could reliably quantify MRI biomarkers in GRMD dogs, suggesting that it would also be useful for quantifying disease progression and measuring therapeutic effect in DMD patients.

Morphological and functional evaluation of chronic pancreatitis with magnetic resonance imaging

Magnetic resonance imaging (MRI) techniques for assessment of morphology and function of the pancreas have been improved dramatically the recent years and MRI is very often used in diagnosing and follow-up of chronic pancreatitis (CP) patients. Standard MRI including fat-suppressed T1-weighted and T2-weighted imaging techniques reveal decreased signal and glandular atrophy of the pancreas in CP. In contrast-enhanced MRI of the pancreas in CP the pancreatic signal is usually reduced and delayed due to decreased perfusion as a result of chronic inflammation and fibrosis. Thus, morphological changes of the ductal system can be assessed by magnetic resonance cholangiopancreatography (MRCP). Furthermore, secretin-stimulated MRCP is a valuable technique to evaluate side branch pathology and the exocrine function of the pancreas and diffusion weighted imaging can be used to quantify both parenchymal fibrotic changes and the exocrine function of the pancreas. These standard and advanced MRI techniques are supplementary techniques to reveal morphological and functional changes of the pancreas in CP. Recently, spectroscopy has been used for assessment of metabolite concentrations in-vivo in different tissues and may have the potential to offer better tissue characterization of the pancreas. Hence, the purpose of the present review is to provide an update on standard and advanced MRI techniques of the pancreas in CP.

Urinary retention in a female patient caused by a urethral venous thrombus with massive edema

Female urinary retention is rarely caused by an unknown condition. In such a case, common causes including neurogenic, anatomical, traumatic and iatrogenic voiding dysfunction are excluded. Both the radiological and histological findings specific to the condition remain unclear. We herein report a 75-year-old woman in whom a large venous mass and massive edema at the proximal urethra caused urinary outlet obstruction based on magnetic resonance images and histological findings. Ultrasonography and cystoscopy showed a urethral mass lesion protruding into the bladder neck. Fat-suppressed T2-weighted and gadolinium-enhanced T1-weighted magnetic resonance images suggested thrombosed veins with massive edema under the urethral mucosa. Transurethral resection of the mass lesion was carried out, and histopathological analysis proved the presence of thrombosed large veins. The patient regained normal urination, and the mass lesion did not recur. Thrombosed venous mass with edema at the proximal urethra might be an important cause of atypical urinary retention in women.

Proximal iliotibial band enthesopathy

A 58-year-old female presented with sudden-onset pain and tenderness at the lateral aspect of the right pelvis occurring after long-distance walking. Physical examination showed a normal range of movements. Magnetic Resonance Imaging (MRI) was performed in order to exclude a stress fracture. Coronal fatsuppressed intermediate weighted images (WI) showed focal thickening and increased signal at the proximal insertion of the right iliotibial tract (ITT) at the iliac tubercle. There was also increased signal surrounding the deep and superficial layers of the ITT (Fig. A, arrows). Axial fatsuppressed T2-WI demonstrated also subtle muscular edema in the adjacent anterior part of the gluteus medius muscle (Fig. B, arrow). There was no evidence of tendon rupture. Based on the imaging findings, the diagnosis of proximal iliotibial band enthesopathy was made. The patient was treated with local infiltration of corticosteroids followed by kinesitherapy.

Lymphoepithelial Cyst of the Pancreas Presenting as a Solid Mass: A Surgery Prevented by Endoscopic Ultrasound

Introduction: Pancreatic cysts can be divided into two types: true cysts with an epithelial lining and pseudocysts. Lymphoepithelial cysts (LECs) are true pancreatic cysts that are benign and rare. LECs have variable appearances on imaging studies, sometimes masquerading as a suspicious solid mass, leading to unnecessary surgical resection. Endoscopic ultrasonography (EUS) with fine-needle aspiration (FNA) can diagnose LECs accurately. We report a rare case of LEC seen as a solid pancreatic mass on MRI but later diagnosed by EUS-FNA. This prevented unwarranted resection of a benign lesion. Case Report: A 55-year-old obese male presented with vague right upper quadrant abdominal pain radiating to the left. He denied any fever, nausea, vomiting, weight loss, or change in bowel habits. He had a history of hypertension, coronary artery disease and dyslipidemia. He was a chronic smoker but denied alcohol or illicit drug use. Family history was significant for colon cancer in a brother. Physical exam was unremarkable and liver function tests were normal. A contrast-enhanced CT scan of the abdomen showed a well-defined, partially cystic, exophytic mass measuring 3.2 cm in the distal pancreatic body. On MRI with contrast, the exophytic mass appeared solid with mild enhancement. The morphology was atypical but no overt invasion of vessels or lymphadenopathy was noted. Differential diagnosis included neoplasms like adenocarcinoma, intraductal papillary mucinous neoplasm, acinar cell tumor or a benign pseudocyst. CEA and CA 19-9 were normal. A EUS with FNA was performed. Cytology revealed benign squamous cells, scattered lymphocytes, cholesterol crystals and debris, consistent with a diagnosis of LEC. A decision was made to observe the patient with serial imaging due to the benign nature of the lesion. Interestingly, a second look at the MRI revealed low signals in T2 and intermediate signals in T1-weighted images. A fat-suppressed T1-weighted image showed relatively high signals because of the keratin content of the cyst, making it appear solid. This characteristic feature of LECs should improve the diagnostic utility of MRI in these cases. Discussion: LECs of the pancreas are rare, benign and predominantly occur in middle-aged men. They are usually incidental with uncertain pathogenesis. Some present with nausea, vomiting, diarrhea or abdominal pain. LECs can be diagnosed on MRI with fat-suppressed T1 images. Definitive diagnosis using EUS-guided FNA can prevent unwarranted surgical resection of this benign lesion as illustrated in this case.

Accuracy of MR findings in characterizing peroneal tendons disorders in comparison with surgery

Previous studies have shown that magnetic resonance imaging (MRI) has a high sensitivity for peroneal tendon pathology but more studies with surgery as a reference standard are needed. To evaluate the accuracy of MRI compared to surgery for characterizing chronic peroneal tendon pathology. Ninety-seven patients (57 men, 40 women; mean age, 39 years; range, 15-64 years) with chronic lateral ankle instability underwent MRI followed by surgery, with a mean MR to surgery interval of 30 days. Sagittal, coronal, and axial T1-weighted spin-echo and fat-suppressed T2-weighted fast spin-echo images were obtained for all patients. Two blinded observers evaluated the MR images without clinical information, and the results were compared to surgical findings. The following peroneal injuries were observed: tendon split, interstitial tear, swelling of the tendon, fluid collection, superior peroneal retinaculum injury, and tendon dislocation. Swelling of the peroneus longus tendon was the most common finding on MR imaging, followed by fluid collection and a split of the peroneus brevis tendon. Surgical findings showed that nine cases (9%) of interstitial tears were in the peroneus brevis and two cases (2%) were in the peroneus longus, with eight cases (8%) of splits in the peroneus brevis tendon. The sensitivity and specificity for detecting interstitial tears in the peroneus brevis were 44% and 99%, respectively. The sensitivity and specificity for detecting swelling in the peroneus brevis were 50% and 99%, respectively. The sensitivity and specificity for detecting interstitial tears for peroneus longus injuries were 50% and 96%, respectively. The sensitivity and specificity for detecting swelling in these injuries were and 100% and 96%, respectively. MRI findings of chronic peroneal tendon pathology are diagnostically specific but not sensitive. MRI showed high sensitivity for diagnosing tendon swelling in the peroneus longus, but not in the peroneus brevis. MRI is sensitive but not specific for detecting negative findings.

Magnetic resonance imaging (MRI) detection of synovitis and bone lesions of the wrists and finger joints in early-stage rheumatoid arthritis: comparison of the accuracy of plain MRI-based findings and gadolinium-diethylenetriamine pentaacetic acid-enhanced MRI-based findings

Objective To explore whether synovitis and bone lesions in the wrists and finger joints visualized by plain magnetic resonance imaging (MRI)-based findings correspond exactly or not to those judged by gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA)-enhanced MRI-based findings.Methods Magnetic resonance imaging of the wrists and finger joints of both hands were examined in 51 early-stage rheumatoid arthritis (RA) patients whose median disease duration from the onset of articular manifestations to entry was 5 months, by both plain (T1 and short-time inversion recovery images) and Gd-DTPA-enhanced MRI (post-contrast fat-suppressed T1-weighted images) simultaneously. We focused on 15 sites per hand, to examine the presence of synovitis and bone lesions (bone edema and bone erosion). Gd-DTPA-enhanced MRI-based findings were considered “true” lesions, and we evaluated the accuracy of plain MRI-based findings in comparison to Gd-DTPA-enhanced MRI-based findings.Results Synovitis, judged by plain MRI-based findings, appeared as false-positive at pretty frequency; thus, the specificity, positive predictive value and accuracy of the findings were low. The rate of enhancement (E-rate) in false-positive synovitis sites was significantly low compared with true-positive synovitis sites where Gd-DTPA enhancement appears. In contrast to synovitis, the false-positivity of bone lesions, judged by plain MRI-based findings, was very low compared with Gd-DTPA-enhanced MRI-based findings.Conclusion Synovitis judged by plain MRI-based findings is sometimes considered false-positive especially in sites where synovitis is mild. However, plain MRI is effective in identifying bone lesions in the wrist and finger joints in early-stage RA.

Detection of focal hepatic lesions with 3-T MRI: comparison of two-dimensional and three-dimensional T2-weighted sequences

To evaluate whether incorporation of a 3D turbo spin-echo sequence during T2-weighted MR imaging improves the detection of focal hepatic lesions by 3T MR imaging. Seventy-nine consecutive patients including 67 patients with 62 malignant and 71 benign lesions and 12 patients having no hepatic lesion underwent respiratory-triggered fat-suppressed axial T2-weighted turbo spin-echo imaging using two-dimensional (2D-TSE) and 3D (3D-TSE) sequences. Coronal multiplanar reformatted images (MPR-3D-TSE) were generated from 3D-TSE images. Breath-hold fat-suppressed 2D axial T2-weighted half-Fourier turbo spin-echo (HF-2D-TSE) images were combined for reading. Two independent radiologists reviewed three imaging sets, (1) 2D-TSE and HF-2D-TSE, (2) 3D-TSE and HF-2D-TSE, and (3) 3D-TSE, HF-2D-TSE and MPR-3D-TSE, for detection of malignant and benign lesions. Lesion-to-liver contrast ratio (CR) and the conspicuity of anatomical boundaries were assessed. For benign lesions, lesion-to-liver CRs with 3D-TSE (2.77 ± 1.91, p = .0002) and MPR-3D-TSE (2.47 ± 1.42, p = .012) were higher than with 2D-TSE (2.13 ± 1.80). Sensitivity for lesions of ≤ 10-mm was higher with 3D-TSE (86 %, p = .0039) and MPR-3D-TSE (84 %, p = .0078) than with 2D-TSE (72 %). However, the edge of left lateral lobe was less conspicuous with 3D-TSE (p < .0001) and MPR-3D-TSE (p = .0003) than with 2D-TSE because of susceptibility artifacts. Incorporation of 3D T2-weighted sequence may incrementally improve the detection of focal hepatic lesions.

MRI of the wrist in juvenile idiopathic arthritis: proposal of a paediatric synovitis score by a consensus of an international working group. Results of a multicentre reliability study

MRI is a sensitive tool for the evaluation of synovitis in juvenile idiopathic arthritis (JIA). The purpose of this study was to introduce a novel MRI-based score for synovitis in children and to examine its inter- and intraobserver variability in a multi-centre study. Wrist MRI was performed in 76 children with JIA. On postcontrast 3-D spoiled gradient-echo and fat-suppressed T2-weighted spin-echo images, joint recesses were scored for the degree of synovial enhancement, effusion and overall inflammation independently by two paediatric radiologists. Total-enhancement and inflammation-synovitis scores were calculated. Interobserver agreement was poor to moderate for enhancement and inflammation in all recesses, except in the radioulnar and radiocarpal joints. Intraobserver agreement was good to excellent. For enhancement and inflammation scores, mean differences (95 % CI) between observers were -1.18 (-4.79 to 2.42) and -2.11 (-6.06 to 1.83). Intraobserver variability (reader 1) was 0 (-1.65 to 1.65) and 0.02 (-1.39 to 1.44). Intraobserver agreement was good. Except for the radioulnar and radiocarpal joints, interobserver agreement was not acceptable. Therefore, the proposed scoring system requires further refinement.