T2-weighted Fat-saturated Sequences Research Articles

MR Neurography in Ulnar Neuropathy as Surrogate Parameter for the Presence of Disseminated Neuropathy

PurposePatients with ulnar neuropathy of unclear etiology occasionally present with lesion extension from elbow to upper arm level on MRI. This study investigated whether MRI thereby distinguishes multifocal neuropathy from focal-compressive neuropathy at the elbow.MethodsThis prospective study was approved by the institutional ethics committee and written informed consent was obtained from all participants. 122 patients with ulnar mononeuropathy of undetermined localization and etiology by clinical and electrophysiological examination were assessed by MRI at upper arm and elbow level using T2-weighted fat-saturated sequences at 3T. Twenty-one patients were identified with proximal ulnar nerve lesions and evaluated for findings suggestive of disseminated neuropathy (i) subclinical lesions in other nerves, (ii) unfavorable outcome after previous decompressive elbow surgery, and (iii) subsequent diagnosis of inflammatory or other disseminated neuropathy. Two groups served as controls for quantitative analysis of nerve-to-muscle signal intensity ratios: 20 subjects with typical focal ulnar neuropathy at the elbow and 20 healthy subjects.ResultsIn the group of 21 patients with proximal ulnar nerve lesion extension, T2-w ulnar nerve signal was significantly (p<0.001) higher at upper arm level than in both control groups. A cut-off value of 1.92 for maximum nerve-to-muscle signal intensity ratio was found to be sensitive (86%) and specific (100%) to discriminate this group. Ten patients (48%) exhibited additional T2-w lesions in the median and/or radial nerve. Another ten (48%) had previously undergone elbow surgery without satisfying outcome. Clinical follow-up was available in 15 (71%) and revealed definitive diagnoses of multifocal neuropathy of various etiologies in four patients. In another eight, diagnoses could not yet be considered definitive but were consistent with multifocal neuropathy.ConclusionProximal ulnar nerve T2 lesions at upper arm level are detected by MRI and indicate the presence of a non-focal disseminated neuropathy instead of a focal compressive neuropathy.

Adhesive Capsulitis of the Shoulder: Value of Inferior Glenohumeral Ligament Signal Changes on T2-Weighted Fat-Saturated Images

The objective of our study was to evaluate the performance of MRI for the diagnosis of adhesive capsulitis using signal intensity changes of the inferior glenohumeral ligament on T2-weighted fat-saturated sequences. MR images of 34 shoulders with a final clinical diagnosis of adhesive capsulitis were compared with those of an age-matched control group (34 shoulders) with no clinical signs of adhesive capsulitis. MR images were acquired before and after IV injection of gadolinium and were evaluated by two readers. The T2 signal intensity at the inferior glenohumeral ligament, the thickness of the coracohumeral ligament, and whether there was obliteration of subcoracoid fat were evaluated on unenhanced images. Enhancement at the inferior glenohumeral ligament and enhancement at the rotator interval were evaluated on contrast-enhanced images. The sensitivity, specificity, and interobserver variability of these signs were calculated. T2 hyperintensity of the inferior glenohumeral ligament showed a high sensitivity (85.3-88.2%) and high specificity (88.2%) for the diagnosis of adhesive capsulitis with excellent interobserver variability (κ = 0.85). Signal analysis at the inferior glenohumeral ligament presented a higher sensitivity and a better interobserver agreement than the other signs of adhesive capsulitis evaluated. Gadolinium injection did not increase the performance of the inferior glenohumeral ligament signal analysis. An extracapsular hyperintense layer on T2-weighted images was identified as a new sign of adhesive capsulitis. T2 capsular signal intensity change offers a high performance for the diagnosis of adhesive capsulitis without the need for IV or intraarticular contrast injection.

Pseudotear of the peroneus longus tendon on MRI, secondary to a fibrocartilaginous node

The purpose of this study was to identify the presence of a fibrocartilaginous node within the distal peroneus longus tendon (PLT) just proximal to the cubital tunnel and correlate this with MRI signal characteristics of the distal PLT, which could result in a pseudotear appearance on MRI. We correlated imaging characteristics with pathologic specimens. Institutional review board approval was obtained. Retrospectively, 91 ankle MRIs utilizing a standard ankle protocol were reviewed by two musculoskeletal radiologists. Four cadaver ankles were imaged using a standard ankle MRI protocol and reviewed by the same radiologists. All the MRIs were examined for signal changes in the PLT. The cadaver ankles then underwent PLT dissection by an orthopaedic surgeon, and a pathologic review was undertaken by a pathologist with orthopaedic specialization, who looked for an os peroneum or proposed fibrocartilaginous node relating to the signal change found on the MRIs. In the 91 ankle MRI studies, the PLT demonstrated normal low and increased signals. On the fat-saturated T2-weighted sequence, 76 (83.5%) ankles demonstrated low signal and 15 (16.5%) demonstrated increased signal. Of the cadaver ankle MRIs, all four demonstrated increased signal within the PLT; three contained a fibrocartilaginous node and one contained an os peroneum in that same region. The MRI signal of the PLT can change with the presence of a fibrocartilaginous node, which may be due to the molecular and chemical content of the fibrocartilage. This node increases the MRI signal in the distal PLT and gives the appearance of a pseudotear.

Magnetic resonance enteroclysis in patients with Crohn's disease: Fat saturated T2-weighted sequences for evaluation of inflammatory activity

Background and aimsTo evaluate fat saturated (fs) T2-weighted (w) fast relaxation fast spin echo (FRFSE)-sequences compared to the standard protocol with contrast agent for the evaluation of inflammatory activity in patients with Crohn's Disease (CD). MethodsFourty-eight patients (male, 17; female, 33; mean age, 37years) with suspicion of inflammatory activity in proven CD who underwent MR enteroclysis (MRE) at 1.5T (GE Healthcare) were retrospectively included. Two blinded radiologists analyzed MRE images for presence and extent of CD lesions and degree of local inflammation for fsT2-w FRFSE and contrast enhanced T1-w images (T2-activity; T1-activity; score, 1–4) in consensus. Furthermore, mural signal intensity (SI) ratios (T2-ratio; T1-ratio) were recorded. Patient based MRE findings were correlated with endoscopic (45 patients), surgical (6 patients), histopathological, and clinical data (CDAI) as a surrogate reference standard. ResultsIn total, 24 of 48 eligible patients presented with acute inflammatory activity with 123 affected bowel segments. ROC analysis of the total inflammatory score presented an AUC of 0.93 (p<0.001) for T2-activity (T1-activity, AUC 0.63; p=0.019). ROC analysis revealed an AUC of 0.76 (p<0.001) for the T2-ratio (T1-ratio, AUC 0.51; p=0.93). General linear regression model revealed T2-activity (p=0.001) and age (p=0.024) as predictive factors of acute bowel inflammation. ConclusionsT2-w FRFSE-sequences can depict CD lesions and help to assess the inflammation activity, even with improved accuracy as compared to contrast-enhanced T1-w sequences.

Grading luminal Crohn's disease: Which MRI features are considered as important?

Magnetic resonance imaging (MRI) is increasingly used for disease activity grading in small bowel Crohn's disease. It is not known which imaging features are essential for grading. For further insight, we solicited the opinion of expert radiologists. A questionnaire about the grading of Crohn's disease was sent to 36 radiologists who had published on MRI grading of Crohn's disease between January 2006 and January 2010. Radiologists were asked which MRI protocol they used, how they graded luminal Crohn's disease, which features they used, how important they considered those features for grading, and which reference standards they used. Twenty-four radiologists responded (66%). They used different protocols and features; most frequently T2-weighted sequences (79%) and contrast enhanced fat saturated T1-weighted sequences (83%). MR-enterography was more often used than MR-enteroclysis (88% versus 33%). Features most frequently considered important for grading were bowel wall thickness (79% of radiologists), the presence of an abscess (75%), T1 enhancement (75%), and T1 stratification (46%). Reference standards differed; most commonly (ileo-) colonoscopy (88%) or surgery (75%) were used. Bowel wall thickness, abscess, T1 enhancement and T1 stratification are most often used for grading. Because of difference in grading, there is need for an international consensus on MRI grading of Crohn's disease.

Magnetic Resonance Imaging of the Throwing Elbow in the Uninjured, High School–Aged Baseball Pitcher

Background: Tissue adaptations in response to pitching are an expected finding during magnetic resonance imaging (MRI) evaluation of the throwing elbow of adult pitchers. These changes are considered normal in the absence of symptom complaints. It is unclear when during the playing career these tissue adaptations are initiated. Hypothesis: Abnormalities in the appearance of the throwing elbow compared with the nonthrowing elbow would be visible during MRI assessment of this asymptomatic population of high school–aged throwers. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Twenty-three uninjured, asymptomatic male high school–aged baseball pitchers (mean age, 16 years) with no history of elbow injury were recruited for the study. Participants had a minimum of 3 years’ experience with pitching as their primary position (mean experience, 6 years). Bilateral elbow MRI examinations were performed using a standardized protocol including fast spin-echo proton-density (axial and coronal), T1-weighted (sagittal), and T2-weighted fat-saturated (axial, sagittal, and coronal) sequences. Osteoarticular, ligamentous, musculotendinous, and neural structures were evaluated and compared bilaterally. The images were reviewed by a musculoskeletal radiologist who was blinded to all the gathered data on these athletes, including limb dominance. Results: Three participants (13%) had no abnormalities. Fifteen individuals (65%) had asymmetrical anterior band ulnar collateral ligament thickening, including 4 individuals who also had mild sublime tubercle/anteromedial facet edema. Fourteen participants (61%) had posteromedial subchondral sclerosis of the ulnotrochlear articulation, including 8 (35%) with a posteromedial ulnotrochlear osteophyte, and 4 (17%) with mild posteromedial ulnotrochlear chondromalacia. Ten individuals (43%) had multiple abnormal findings in the throwing elbow. Conclusion: Thickening of the anterior band of the ulnar collateral ligament and posteromedial subchondral sclerosis of the trochlea are common findings in the high school–aged pitcher and may be considered normal clinical findings in the absence of symptom complaints. Other changes in tissue appearance of the throwing elbow are uncommon in this age group and should be regarded with a higher level of caution when evaluating for the presence of injury. An understanding of the MRI appearance of the uninjured youth pitcher is necessary for clinicians to distinguish between normal adaptations and the presence of injury.

MRI and PET/CT of patients with bone metastases from breast carcinoma

3.0Tesla magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) was compared with combined 18F-fluorodeoxyglucose positron emission tomography and computed tomography (PET/CT) in patients with suspected bone metastases from breast cancer. A prospective clinical study was performed in 13 female breast cancer patients (mean age 61years; range 45-85 years). The spine was imaged in the sagittal plane with T1-weighted (T1), short tau inversion recovery (STIR), and T2-weighted fat-saturated (T2) sequences. The pelvis was imaged similarly in the coronal plane. Axial DWI was performed from the skull base to the mid-thigh. MRI and PET/CT were performed in all patients at a maximum interval of 10 working days and at least 14 days after chemotherapy. MRI was reviewed by two radiologists, and their consensus on potential metastases in 27 predefined locations was recorded. The predefined locations were the vertebral bodies (24), the left (1) and right (1) pelvic bones, and the sacral bone (1). The PET/CT was reviewed by a radiologists and a nuclear medicine physician. MRI detected 59 of the 60 active metastases found with our gold standard modality PET/CT. T1 had the highest sensitivity (98%) but rather low specificity (77%), but with the addition of STIR and DWI, the specificity increased to 95%. The additional metastases detected with MRI most likely represented postherapeutic residual scars without active tumour. In conclusion, 3.0Tesla MRI with T1, STIR, and DWI is useful for the clinical evaluation of bone metastases from breast cancer and compares well to PET/CT.

Primary Hepatic Lymphoma: A Large Mass Surrounding Multiple Intrahepatic Vessels

A man was hospitalized for a 7-day history of right upper-quadrant abdominal pain. Physical examinaion revealed mild hepatomegaly. Laboratory results showed a emoglobin level of 94 g/L, a platelet count of 66 109 g/L, a actate dehydrogenase level of 554 U/L, an alkaline phosphatase evel of 118 U/L, and a -glutamyl transpeptidase level of 65 U/L. Tumor markers were negative. Abdominal computed tomography (CT) with contrast revealed a 15.0 10.0 8.4 cm3 nonenhancing mass involving the right and left lobes of the liver on portal phase imaging (Figure A). Magnetic resonance imaging showed low signal on T1-weighted and high signal on T2-weighted fat-saturated sequences (Figure B). The mass showed mild rim enhancement on portal phase postcontrast T1-weighted sequence and surrounded the inferior vena cava, hepatic middle and right vein, and right portal vein without any deformity (Figure C). There was no mediastinal lymphadenopathy on chest radiography and no evidence of lymphoma on bone marrow biopsy. Liver biopsy showed diffuse lymphocytic infiltrate (Figure D). Immunohistochemical stains were positive for CD20 (Figure E), CD79a, and Ki-67 ( 40%), and negative for CD45RO. The diagnosis of diffuse B-cell lymphoma was made. After 6 cycles of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone, CT showed a dramatic reduction in the size of the tumor (Figure F). The patient was followed up for 2 years without recurrence or the need for additional therapy. This case highlighted several important points. A large mass surrounding multiple intrahepatic blood vessels without any architectural distortion was the characteristic of this tumor, which was to some extent similar to the sandwich sign for mesenteric lymphoma and the CT angiogram sign or floating aorta sign for retroperitoneal lymphoma. This finding is helpful in differentiating primary hepatic lymphoma (PHL) from most benign or malignant hepatic tumors that usually displace or invade the adjacent intrahepatic vessels. Lymphoma in general tends to surround adjacent vessels without compressing their lumen.1 Furthermore, although rare,2 it is important to rec-

Book review

Book review

Athletic injuries of the extensor carpi ulnaris subsheath: MRI findings and utility of gadolinium-enhanced fat-saturated T1-weighted sequences with wrist pronation and supination

To report the magnetic resonance imaging (MRI) findings in athletic injuries of the extensor carpi ulnaris (ECU) subsheath, assessing the utility of gadolinium-enhanced (Gd) fat-saturated (FS) T1-weighted sequences with wrist pronation and supination. Sixteen patients (13 male, three female; mean age 30.3 years) with athletic injuries of the ECU subsheath sustained between January 2003 and June 2009 were included in this retrospective study. Initial and follow-up 1.5-T wrist MRIs were performed with transverse T1-weighted and STIR sequences in pronation, and Gd FS T1-weighted sequences with wrist pronation and supination. Two radiologists assessed the type of injury (A to C), ECU tendon stability, associated lesions and rated pulse sequences using a three-point scale: 1=poor, 2=good and 3=excellent. Gd-enhanced FS T1-weighted transverse sequences in supination (2.63) and pronation (2.56) were most valuable, compared with STIR (2.19) and T1-weighted (1.94). Nine type A, one type B and six type C injuries were found. There were trends towards diminution in size, signal intensity and enhancement of associated pouches on follow-up MRI and tendon stabilisation within the ulnar groove. Gd-enhanced FS T1-weighted sequences with wrist pronation and supination are most valuable in assessing and follow-up athletic injuries of the ECU subsheath on 1.5-T MRI.

Book review

Book review

Magnetic resonance imaging grading system for active and chronic spondylarthritis changes in the sacroiliac joint

To develop a new grading method to quantify activity and chronic spondylarthritis (SpA) changes in the sacroiliac (SI) joints identified by magnetic resonance imaging (MRI), taking into account the complex joint anatomy, and to compare the findings with radiographic changes. A total of 37 patients (15 men, 22 women) fulfilling the European Spondylarthropathy Study Group criteria for SpA were examined by MRI of the SI joint using a semicoronal T1-weighted and T1-weighted fat-saturated (T1FS) sequence, a semiaxial STIR sequence, and postcontrast semicoronal and semiaxial T1FS sequences. The images were assessed independently by 2 radiologists for presence of bone marrow edema and enhancement, fatty marrow deposition, and joint erosion at both the cartilaginous and the ligamentous joint portion. Conventional radiographs were scored in accordance with the modified New York criteria. Inter- and intraobserver agreements for grading activity and chronic changes were good, with kappa values between 0.72 and 0.86 and between 0.83 and 0.90, respectively. Nearly half of the disease activity changes were due to inflammation in the ligamentous joint portion, which was significantly related to ankylosing spondylitis (AS). Patients with AS had significantly higher erosion and fatty marrow deposition scores than patients with nonprimary AS forms of SpA. The degree of erosion by MRI was significantly related to radiographic stages. Separate assessment of the ligamentous joint portion by MRI may be valuable for differentiating AS from nonprimary AS forms of SpA. Erosive changes on MRI were significantly related to radiographic changes, implying a possibility for substituting radiography with MRI.

Comparison of 1.0 M Gadobutrol and 0.5 M Gadopentetate Dimeglumine-Enhanced Magnetic Resonance Imaging in Five Hundred Seventy-Two Patients With Known or Suspected Liver Lesions

To evaluate the diagnostic efficacy (accuracy, sensitivity, specificity) of 1.0 M gadobutrol versus 0.5 M gadopentetate for the classification of lesions as either benign or malignant in patients with known or suspected liver lesions. A multicenter, phase-III, randomized, interindividually controlled comparison study with blinded reader evaluation was performed to investigate the diagnostic efficacy of a bolus injection of 1.0 M gadobutrol compared with 0.5 M gadopentetate at a dose of 0.1 mmol Gd/kg BW. The imaging protocol included a dynamic 3D-evaluation, static conventional, and fat saturated T1-weighted sequences. MR datasets were evaluated by 3 independent radiologists. The standard of reference was defined by an independent truth panel (radiologist or hepatologist). The safety evaluation included adverse events, vital signs, and physical examination. A total of 497 of 572 patients were eligible for the final efficacy analysis. Noninferiority of gadobutrol-enhanced magnetic resonance imaging (MRI) for the classification of liver lesions was demonstrated on the basis of diagnostic accuracy determined by the on-site investigators (-0.098, 0.021) as well as for the average reader of the blinded evaluation (-0.096, 0.014) (95% confidence interval), compared with the predefined standard of reference. Very similar increases in sensitivity (ranging from approximately 10% to approximately 55%) and specificity (ranging from approximately 1% to approximately 18%) compared with precontrast MRI were also observed for the 2 contrast agent groups, with maximum differences of 4%.Very similar, low rates of adverse events were recorded for each of the 2 groups. No clinically relevant changes in vital signs or the results of the physical examination were observed in any patient. This study documents evidence for the noninferiority of a single i.v. bolus injection of 1.0 M gadobutrol (0.1 mmol/kg body weight) to 0.5 M gadopentetate (0.1 mmol/kg body weight) in the diagnostic assessment of liver lesions with contrast-enhanced MRI. The known excellent safety profile of gadobutrol was confirmed in this clinical trial and is similar to that of gadopentetate.

MRI bone oedema scores are higher in the arthritis mutilans form of psoriatic arthritis and correlate with high radiographic scores for joint damage

IntroductionThe aim of this study was to investigate the magnetic resonance imaging (MRI) features of bone disease in the arthritis mutilans (AM) form of psoriatic arthritis (PsA).MethodsTwenty-eight patients with erosive PsA were enrolled (median disease duration of 14 years). Using x-rays of both hands and feet, 11 patients were classified as AM and 17 as non-AM (erosive psoriatic arthritis without bone lysis)by two observers. MRI scans (1.5T) of the dominant hand (wrist and fingers scanned separately) were obtained using standard contrast-enhanced T1-weighted and fat-saturated T2-weighted sequences. Scans were scored separately by two readers for bone erosion, oedema and proliferation using a PsA MRI scoring system. X-rays were scored for erosions and joint space narrowing.ResultsOn MRI, 1013 bones were scored by both readers. Reliability for scoring erosions and bone oedema was high (intraclass correlation coefficients = 0.80 and 0.77 respectively) but only fair for bone proliferation (intraclass correlation coefficient = 0.42). MRI erosion scores were higher in AM patients (53.0 versus 15.0, p = 0.004) as were bone oedema and proliferation scores (14.7 versus 10.0, p = 0.056 and 3.6 versus 0.7, p = 0.003 respectively). MRI bone oedema scores correlated with MRI erosion scores and X-ray erosion and joint space narrowing scores (r = 0.65, p = 0.0002 for all) but not the disease activity score 28-C reactive protein (DAS28CRP) or pain scores.ConclusionsIn this patient group with PsA, MRI bone oedema, erosion and proliferation were all more severe in the AM-form. Bone oedema scores did not correlate with disease activity measures but were closely associated with X-ray joint damage scores. These results suggest that MRI bone oedema may be a pre-erosive feature and that bone damage may not be coupled with joint inflammation in PsA.

MR imaging changes in the trochanteric area of asymptomatic individuals: A potential for misdiagnosis of pain in the trochanteric region

Objective To investigate the MR imaging appearance of the trochanteric region in a group of patients referred for non-musculoskeletal conditions. Materials and methods Forty-five patients ( n = 90 hips) referred for non-musculoskeletal conditions were imaged with a coronal T1 weighted fat saturated sequence after intravenous administration of contrast medium. Findings were interpreted by consensus of two experienced radiologists. Results In 54 of 90 hips (60%) no signal changes were seen at the level of the greater trochanter. A linear area of contrast enhancement with a craniocaudal dimension of less than 3 cm, and thickness less than 0.3 cm was seen in 32 of 90 hips (35.6%). A fusiform area of contrast enhancement with a craniocaudal dimension of more than 3 cm, and thickness more than 0.3 cm was seen in 4 hips (4.4%). Conclusion An area of signal abnormality may be seen on contrast enhanced studies in asymptomatic persons, located in between the gluteus medius tendon and iliotibial band, and this should not be considered as a cause of pain in the trochanteric region.

Radiological findings and healing patterns of incomplete stress fractures of the pars interarticularis

The objective was to retrospectively record the CT and MRI features and healing patterns of acute, incomplete stress fractures of the pars interarticularis. The CT scans of 156 adolescents referred with suspected pars interarticularis stress fractures were reviewed. Patients with incomplete (grade 2) pars fractures were included in the study. Fractures were assessed on CT according to vertebral level, location of cortical involvement and direction of fracture propagation. MRI was also performed in 72 of the 156 cases. MRI images of incomplete fractures were assessed for the presence of marrow oedema and cortical integrity. Fracture healing patterns were characterised on follow-up CT imaging. Twenty-five incomplete fractures were identified in 23 patients on CT. All fractures involved the inferior or infero-medial cortex of the pars and propagated superiorly or superolaterally. Ninety-two percent of incomplete fractures demonstrated either complete or partial healing on follow-up imaging. Two (8%) cases progressed to complete fractures. Thirteen incomplete fractures in 11 patients confirmed on CT also had MRI, and 92% demonstrated oedema in the pars. Ten out of thirteen fractures (77%) showed a break in the infero-medial cortex with intact supero-lateral cortex, which correlated with the CT findings. MRI incorrectly graded one case as a complete (grade 3) fracture, and 2 cases as (grade 1) stress reaction. Six fractures had follow-up MRI, 67% showed partial or complete cortical healing, and the same number showed persistent marrow oedema. Incomplete fracture of the pars interarticularis represents a stage of the evolution of a complete stress fracture. The direction of fracture propagation is consistent, and complete healing can be achieved in most cases with appropriate clinical management. CT best demonstrates fracture size and extent, and is the most appropriate modality for follow-up. MRI is limited in its ability to fully depict the cortical integrity of incomplete fractures of the pars, but the presence of marrow oedema on fat-saturated T2-weighted sequences is a useful means of detecting acute spondylolysis.

Optimal 3-T MRI for depiction of the finger A2 pulley: comparison between T1-weighted, fat-saturated T2-weighted and gadolinium-enhanced fat-saturated T1-weighted sequences

To compare three spin-echo sequences, transverse T1-weighted (T1WI), transverse fat-saturated (FS) T2-weighted (T2WI), and transverse gadolinium-enhanced (Gd) FS T1WI, for the visualisation of normal and abnormal finger A2 pulley with magnetic resonance (MR) imaging at 3 tesla (T). Sixty-three fingers from 21 patients were consecutively investigated. Two musculoskeletal radiologists retrospectively compared all sequences to assess the visibility of normal and abnormal A2 pulleys and the presence of motion or ghost artefacts. Normal and abnormal A2 pulleys were visible in 94% (59/63) and 95% (60/63) on T1WI sequences, in 63% (40/63) and 60% (38/63) on FS T2WI sequences, and in 87% (55/63) and 73% (46/63) on Gd FS T1WI sequences when read by the first and second observer, respectively. Motion and ghost artefacts were higher on FS T2WI sequences. Seven among eight abnormal A2 pulleys were detected, and were best depicted with Gd FS T1WI sequences in 71% (5/7) and 86% (6/7) by the first and the second observer, respectively. In 3-T MRI, the comparison between transverse T1WI, FS T2WI, and Gd FS T1WI sequences shows that transverse T1WI allows excellent depiction of the A2 pulley, that FS T2WI suffers from a higher rate of motion and ghost artefacts, and transverse Gd FS T1WI is the best sequence for the depiction of abnormal A2 pulley.

MR imaging findings of anterior interosseous nerve lesions

To study and characterise the MR imaging findings of lesions of the anterior interosseous nerve (AIN). Magnetic resonance imaging (MRI) findings of the forearm of ten patients referred to our institution with suspected AIN lesions were retrospectively studied. Five healthy volunteers with normal forearm MRI findings formed a control group. Two musculoskeletal radiologists assessed the forearm musculature for oedema in the distribution of the AIN, median, posterior interosseous and radial nerves on T2-weighted (T2W) fat-saturated sequences. T1-weighted (T1W) images were assessed and graded for the presence of muscle atrophy and fatty involution. Six patients had undergone surgical exploration; five of these had surgically confirmed AIN compression. Four patients had diagnoses other than AIN compression made on imaging features. Of the cases of proven AIN compression, oedema within the pronator quadratus (PQ) muscle was identified in all cases. PQ atrophy and fatty involution were seen in three (43%) surgically confirmed cases. Cases 2 and 3 also demonstrated oedema in the flexor digitorum profundus (FDP)1 and FDP2 muscles. These cases also showed oedema in the flexor-carpi radialis (FCR) and FDP3/FDP4 muscles, respectively. The four cases of non-AIN compression demonstrated muscle oedema patterns that were atypical for the AIN distribution. They included a rupture of the flexor pollicis longus (FPL) tendon, brachial neuritis, amyotrophic lateral sclerosis and compression of the proximal median nerve. MRI is a useful investigation in the diagnostic workup of AIN syndrome. AIN syndrome is likely when there is diffuse oedema of AIN innervated muscles on T2W fat-saturated images. The most reliable sign of an AIN lesion is oedema within the PQ. Oedema in the flexor carpi radialis, FDP3 and FDP4, although not in the classical distribution of the AIN, does not preclude the diagnosis of AIN syndrome.

Evaluation of radial-sequence imaging in detecting acetabular labral tears at hip MR arthrography

In recent years, radial imaging has been advocated for improved visualization of the acetabular labrum in magnetic resonance arthrography of the hip. The purpose of this study was to investigate whether radial imaging demonstrates labral tears not visible on standard imaging planes. Fifty-four consecutive magnetic resonance (MR) arthrograms of the hip that included radial imaging over 2 years were retrospectively analyzed by two radiologists. Standard imaging planes and radial imaging were reviewed for identification of labral tears in four specific areas of the labrum: anterosuperior, posterosuperior, anteroinferior, and posteroinferior. The standard imaging sequences include fat-saturated spin-echo T1-weighted images in the coronal and oblique axial planes, non-fat-saturated T1-weighted images in the coronal and sagittal planes, and T2-weighted sequence in the axial plane. Radial imaging was performed as previously described using fat-saturated T1-weighted sequences. Using standard imaging planes, 50 anterosuperior, 31 posterosuperior, 10 anteroinferior, and 9 posteroinferior labral tears were detected in 54 MR arthrograms of the hip. Using radial sequences alone, 44 anterosuperior, 25 posterosuperior, 9 anteroinferior, and 5 posteroinferior labral tears were detected. In all four areas of the labrum, the radial imaging did not show any labral tear not seen on standard imaging planes. In MR arthrography of the hip, radial imaging did not reveal any additional labral tears. Standard imaging planes sufficiently demonstrate all acetabular labral tears.

Comparison of prenatal and postnatal MRI findings in the evaluation of intrauterine CNS anomalies requiring postnatal neurosurgical treatment

To assess the diagnostic capability of fetal magnetic resonance imaging (MRI) in children suspected antenatally to harbor central nervous system (CNS) defects that require immediate postnatal neurosurgical treatment. Between 2003 and 2005, 13 fetal MRI scans were performed in mothers suspected to have fetuses with congenital CNS defects that would require surgery soon after birth. Comparisons between antenatal and postnatal scans were made with emphasis on diagnostic accuracy of antenatal examinations. All mothers were scanned using heavily T2-weighted fat-saturated sequences, allowing rapid acquisitions to avoid movement artefacts. Imaging quality was satisfactory in all patients. Diagnoses made antenatally were: myelomeningocele in seven, meningocele in one, diastematomyelia in one, occipital meningocele in one, and isolated hydrocephalus in three children. Of the seven children with antenatal diagnosis of myelomeningocele, one proved to have spinal lipoma postnatally. The patient who antenatally was diagnosed with meningocele proved to have spinal lipoma postnatally. These two were early antenatal MR scans. Antenatal diagnosis of hydrocephalus was made in five of the six confirmed myelomeningocele patients, which was verified postnatally. Antenatal diagnosis of Chiari II malformation was made in all six confirmed myelomeningocele patients. The antenatal diagnoses of occipital meningo-encephalocele and isolated hydrocephalus were verified postnatally. Antenatal diagnosis of diastematomyelia was not verified postnatally. Fetal MRI scanning is an effective, noninvasive method of assessing in-utero CNS abnormalities. The diagnostic accuracy has improved to allow prediction of clinical outcome and counseling for possible treatment, but is not perfect yet to allow counseling for termination of pregnancy.