Fat-suppressed T2-weighted Magnetic Resonance Imaging Research Articles

Symptomatic bone marrow lesions induced by reduced bone mineral density in middle-aged women: a cross-sectional Japanese population study

BackgroundThe etiology of bone marrow lesions (BMLs) without knee osteoarthritis (KOA) and their association with bone fragility are unclear. We aimed to investigate the association between BMLs, bone mineral density (BMD), and bone markers in women without radiographic evidence of KOA.MethodsThis single-center cross-sectional study in a Japanese population included 266 women without radiographic evidence of KOA, which was defined as a Kellgren-Lawrence grade < 2. All participants underwent coronal and sagittal T2-weighted fat-suppressed magnetic resonance imaging of their right knee. BML severity was scored according to the Whole-Organ MRI Scoring method. BMD was measured by dual-energy X-ray absorptiometry of the forearm. Levels of bone markers (bone-alkaline phosphatase [BAP], type I procollagen N-terminal propeptide [PINP], cross-linked N-telopeptide of type I collagen [NTx], and tartrate-resistant acid phosphatase-5b [TRACP-5b]), pentosidine, and homocysteine were assessed in the serum. Knee symptoms were evaluated on the basis of the Knee injury and Osteoarthritis and Outcome Score (KOOS). Participants were divided into symptomatic knee and asymptomatic knee groups on the basis of their KOOS according to the classification criteria for early KOA. Multiple linear regression analysis was performed to evaluate the relationship between BMLs, BMD, and bone markers.ResultsThe prevalence of BML was 35.3%. Age and some bone marker levels (BAP, PINP, NTx, and TRACP-5b) were higher, and all KOOS subscale scores and BMD were lower in participants with BMLs than in those without BMLs. On multiple linear regression analysis, BMD was negatively associated with BMLs (p = 0.014) in participants with symptomatic knees. There was no such association in participants with asymptomatic knees (p = 0.918). Among the bone markers, BAP (p = 0.006) and PINP (p = 0.043) were positively associated with BMLs in participants with symptomatic knees, while BAP (p = 0.038) and TRACP-5b (p = 0.011) were positively associated with BMLs in participants with asymptomatic knees.ConclusionsIn symptomatic Japanese women without radiographic evidence of KOA, BMD is negatively associated and some bone markers are positively associated with BMLs after adjustment for age and BMI. Thus, maintaining systemic bone metabolism could contribute to BML prevention in patients with pre-radiographic KOA.

Orbital Interstitial Fluid: Evidence of a Potential Pathway for Extracranial Cerebrospinal Fluid Absorption.

The aim of the study was to describe the prevalence and characteristics of orbital interstitial fluid seen on magnetic resonance (MR) images of infants and young children. Fat-suppressed axial T2-weighted MR images of 100 consecutive infants and young children (<6 years) without orbital pathology were retrospectively reviewed by 2 neuroradiologists. The presence, location, and extent of high-signal orbital interstitial fluid were characterized and tabulated as a function of age. Orbital interstitial fluid was detected in 90 (90%) of the 100 subjects overall, present in 100% (75/75) of infants and children younger than 3 years, 75% (12/16) of those aged 3 to 5 years, and 33% (3/9) of those aged 5 to 6 years. The fluid was bilateral and symmetric in all cases. Two morphologic patterns were distinguished, which often co-existed: (1) a focal discrete curvilinear band of fluid in the posterior-lateral orbit, more common in younger patients, and (2) an ill-defined, lace-like pattern primarily in the superior orbit seen in subjects of all ages. Orbital interstitial fluid as detected by fat-suppressed T2-weighted MR imaging is a nearly universal finding in infants and young children and should not be considered pathologic. It may have either a focal or lace-like pattern or both. Orbital interstitial fluid decreases in size and prevalence as a function of age but is still present in nearly half of children aged 4 to 6 years. Possible explanations concerning the nature and origin of this fluid are presented, including the fascinating possibility that the fluid represents an extracranial pathway for outflow of cerebrospinal fluid.

The Role of Fast Imaging Employing Steady-State Acquisition (FIESTA) Magnetic Resonance Imaging for Assessment of Delayed Enhancement of Fat Graft Packing on Postoperative Imaging After Vestibular Schwannoma Surgery.

To investigate the role and efficacy of fast imaging employing steady-state acquisition (FIESTA) imaging in distinguishing fat graft enhancement from residual or recurrent tumor after vestibular schwannoma (VS) surgery. A retrospective study of 33 patients who underwent VS resection via the retrosigmoid or translabyrinthine approach with fat graft reconstruction was performed. Magnetic resonance imaging (MRI) was collected at different time points: preoperative, immediate postoperative (24-48 hours), delayed postoperative (3-6 months after surgery), and yearly postoperative. The image sets contained T1, T2, fat-suppressed T1-weighted with gadolinium, and FIESTA. The radiographs were analyzed for tumor recurrence by the primary neurosurgeon and an independent blinded neuroradiologist. If fat-suppressed T1-weighted images demonstrated postoperative enhancement in the resection bed, a comparison was made with FIESTA imaging. At 3-6 months postoperatively and at 1 year and beyond, 28 (84.8%) and 33 (100%) of patients, respectively, displayed delayed enhancement of the fat graft on postgadolinium fat-suppressed T1-weighted MRI. The enhancement seen on postgadolinium, fat-suppressed, T1-weighted MRI consistently correlated with the characteristic fat graft signal on FIESTA imaging and not tumor recurrence. FIESTA imaging was able to distinguish residual tumor from enhancing fat graft compared with postgadolinium, fat-suppressed, T1-weighted MRI (P < 0.0001) due to distinctive signaling patterns. FIESTA is an effective tool in discerning fat graft enhancement from residual or recurrent tumor on delayed postoperative imaging after VS resection. Fat graft used in reconstruction consistently enhances on delayed postoperative postgadolinium, fat-suppressed, T1-weighted imaging, which correlates with the fat graft signal seen on FIESTA images.

Pretreatment MR imaging radiomics signatures for response prediction to induction chemotherapy in patients with nasopharyngeal carcinoma

PurposeThis study aimed to investigate the capability of magnetic resonance (MR) imaging radiomics signatures for pretreatment prediction of early response to induction chemotherapy in patients with nasopharyngeal carcinoma (NPC). Materials and methodsThis was a retrospective study consisting of 120 patients with biopsy-proven NPC (stage II–IV). Texture features were extracted from the pretreatment morphological MR images for each case. Radiomics signatures were obtained with the least absolute shrinkage and selection operator method (LASSO) logistic regression model. The association between the radiomics signatures and the early response to induction chemotherapy was explored. ResultsFrom the contrast-enhanced T1-weighted MR imaging (CE T1WI), 5 features were selected by the LASSO model. The radiomics signature categorised patients with NPC into response and nonresponse groups (P<0.001). The area under the receiver operating characteristic curve values (AUC), sensitivity, specificity, positive predictive value (PPV) and negative predictive value(NPV) were 0.715(95% CI 0.699–0.731), 0.940, 0.500, 0.568 and 0.897 respectively, where non-responders are true-positives. The AUC of 1000 bootstrap internal validation was 0.715. Furthermore, when the features of T1-weighted MR imaging (T1WI), T2-weighted MR imaging (T2WI), T2-weighted fat-suppressed MR imaging (T2WI FS) and CE T1WI were analysed together, 15 features were selected to develop the radiomics signature. The performance of this radiomics signature was better than that developed only from CE T1WI (P<0.05). The AUC value was 0.822(95% CI 0.809–0.835) with sensitivity of 0.980, specificity of 0.529, PPV of 0.593 and NPV of 0.949. The AUC of 1000 bootstrap analysis was 0.821. From T1WI, T2WI, and T2WI FS images separately, no valuable features were selected. ConclusionsPretreatment morphological MR imaging radiomics signatures can predict early response to induction chemotherapy in patients with NPC.

Discrepant lesion size estimated on T1- and fat-suppressed T2-weighted MRI: diagnostic value for differentiation between inflammatory pseudotumor and carcinoma of the nasopharynx.

Nasopharyngeal inflammatory pseudotumor (NIPT) is hard to differentiate from infiltrating nasopharyngeal carcinoma (NPC) on conventional magnetic resonance imaging (MRI). The purpose of this study is to determine whether discrepant lesion sizes estimated on T1- and fat-suppressed T2-weighted images can help distinguish between NIPT and NPC. We retrospectively reviewed MRI data of histologically proven 14 NIPTs and 18 infiltrating NPCs. We measured the area of the lesion on contrast-enhanced T1-weighted, unenhanced T1-weighted, and fat-suppressed T2-weighted images by placing the largest possible polygonal region-of-interest within the lesion at the same level. Using lesion size measured on contrast-enhanced T1-weighted image as the reference, we calculated and compared area ratio of T1 (ART1) and area ratio of T2 (ART2) between NIPTs and NPCs. For validation, we also undertook a double-blinded study by two reviewers and assessed the diagnostic performance and interobserver agreement. For NIPTs, ART2 (median, 0.48; range, 0.18-0.97) was statistically significantly less than ART1 (median, 1.01; range, 0.80-1.99), while these values were not significantly different for NPCs. The interobserver agreement in differentiating between NIPT and NPC was good, with a sensitivity of 93% and a specificity of 83%-94%. In contrast to NPCs, NIPTs appear smaller on fat-suppressed T2-weighted images than on T1-weighted images. This discrepancy in the lesion size estimated on T1-weighted and fat-suppressed T2-weighted images may provide a simple and consistent way to differentiate between NIPTs and NPCs on conventional MRI.

Periportal lymphatic system on post-hepatobiliary phase Gd-EOB-DTPA-enhanced MR imaging in normal subjects and patients with chronic hepatitis C.

We sought to evaluate visualization of periportal lymphatics and lymph nodes (lymphatic system) on Gd-EOB-DTPA-enhanced magnetic resonance (MR) images using a fat-suppressed T2-weighted sequence with 3-dimensional (3D) volume isotropic turbo spin echo acquisition (VISTA) at 3.0 T in normal subjects and patients with chronic hepatitis C. MR imaging was performed in 254 subjects between June 2013 and May 2016. After applying inclusion and exclusion criteria, the final population was 31 normal subjects and 34 patients with chronic hepatitis C. Images were acquired after the hepatobiliary phase following intravenous administration of Gd-EOB-DTPA, which causes signal loss in the bile ducts, to facilitate the visualization of the periportal lymphatic system. Two radiologists assessed the visualization of the periportal lymphatic system in 31 normal subjects. The axial dimensions of the main periportal lymphatic system in normal subjects were measured and compared with those of 34 patients with chronic hepatitis C using the Mann-Whitney U-test, and their correlation with a hepatic fibrosis marker, the Fibrosis-4 (FIB-4), was assessed using Spearman's rank correlation test. The periportal lymphatic system was detected as high signal intensity areas surrounding the portal vein up to the third branches by each reader in all normal subjects. The axial dimensions of the main periportal lymphatic system in patients with chronic hepatitis C were significantly larger than those in normal subjects (p<0.0001), and showed a significantly positive correlation with the FIB-4 score (ρ=0.73, p<0.001). Fat-suppressed T2-weighted MR imaging with 3D-VISTA acquired after the hepatobiliary phase on Gd-EOB-DTPA-enhanced imaging may be a useful noninvasive method for evaluating the periportal lymphatic system and the degree of hepatic fibrosis.

Hypointense signals in the infrapatellar fat pad assessed by magnetic resonance imaging are associated with knee symptoms and structure in older adults: a cohort study.

BackgroundThere are few clinical and epidemiological studies reporting the association between abnormal changes within the IPFP and knee osteoarthritic changes. This study aims to describe the associations between hypointense signals in the infrapatellar fat pad (IPFP) and knee structural change and symptoms in older adults.MethodsParticipants (n = 874) were selected randomly from local community and followed up 2.7 years later (range 2.6–3.3 years). T1- or T2-weighted fat-suppressed magnetic resonance imaging (MRI) was assessed for IPFP hypointense signal, cartilage volume, cartilage defects, and bone marrow lesions (BMLs). Knee pain was assessed by self-administered Western Ontario and McMaster Osteoarthritis Index (WOMAC) questionnaire. Radiographic osteoarthritis was assessed using the OARSI atlas.ResultsCross-sectionally, hypointense signals in the IPFP were significantly associated with a higher risk of knee cartilage defects at all sites, tibiofemoral BMLs and knee pain in multivariable analyses. Longitudinally, baseline signal abnormalities were significantly and positively associated with increases in knee cartilage defects (OR: 2.27, 95 % CI: 1.61–3.21), BMLs (OR: 1.91, 95 % CI: 1.39–2.62), and knee pain (OR: 1.36, 95 % CI: 1.05–1.76) in multivariable analyses. The associations with cartilage defects remained significant after adjustment for BMLs, but the associations with BMLs and knee pain decreased in magnitude or became non-significant after further adjustment for cartilage defects.ConclusionsHypointense signals in the IPFP were associated primarily with increased knee cartilage defects and also with BMLs and knee symptoms in cross-sectional and longitudinal analyses, suggesting the abnormality represented by this signal has a potentially important role in osteoarthritis progression.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-016-1130-y) contains supplementary material, which is available to authorized users.

Preoperative magnetic resonance imaging evaluation of semitendinosus tendon in anterior cruciate ligament reconstruction: Does this have an effect on graft choice?

Background:Anterior cruciate ligament (ACL) reconstruction with ST autograft is sometimes unsuccessful because of harvested thin graft. Magnetic resonance imaging (MRI) can be a useful tool to evaluate the thickness of the graft. This study is performed to evaluate whether there is any correlation between diameters and cross-sectional area (CSA) of the semitendinosus tendon (ST) on the preoperative magnetic MRI and the diameter of the 4-stranded ST autograft in ACL reconstruction.Materials and Methods:Seventy patients who underwent single-bundle ACL reconstruction with 4-stranded ST for full-thickness ACL ruptures were included in this study. Anteroposterior (AP) and mediolateral (ML) diameters of ST at the levels of the joint line (JL) and femoral physeal line (PL), and also CSA at these levels were measured on T2-weighted fat-suppressed MRI examinations. The data obtained were compared with intraoperatively measured diameters of 4-stranded ST autograft. Correlations between variables were evaluated using Spearman's rho. Receiver operating characteristic and area under the curve statistics were used to evaluate the cut-off value for the correlation between 4-stranded ST graft diameter of 8 mm and CSA (mm2) on MRI.Results:On MRI measurements, no correlation was found between AP diameters at the level of the JL and 4-stranded ST diameter (P = 0.180). However, correlations were found between diameter of 4-stranded ST and ML diameter at the level of JL (P = 0.003) and PL (P = 0.002), AP diameter at the level of the PL (P = 0.009), CSA at the level of the JL (P < 0.001) and at the level of PL (P < 0.001). Correlation between the diameter of 4-stranded ST and CSA at both levels was more significant than that between AP-ML diameters of ST and diameter of autograft. The cut-off value for the 8 mm diameter CSA of 4-stranded ST was 5.9 mm2 at the JL and 8.99 mm2 at the PL.Conclusion:Preoperative MRI evaluation of CSA at the JL of the ST is a reliable parameter to predict graft size. Other graft alternatives should better be considered if the CSA of ST is <5.9 mm2 at the level of the JL.

Postmortem Study of Validation of Low Signal on Fat-Suppressed T1-Weighted Magnetic Resonance Imaging as Marker of Lipid Core in Middle Cerebral Artery Atherosclerosis.

Background and Purpose—High signal on T1-weighted fat-suppressed images in middle cerebral artery plaques on ex vivo magnetic resonance imaging was verified to be intraplaque hemorrhage histologically. However, the underlying plaque component of low signal on T1-weighted fat-suppressed images (LST1) has never been explored. Based on our experience, we hypothesized that LST1 might indicate the presence of lipid core within intracranial plaques.Methods—1.5 T magnetic resonance imaging was performed in the postmortem brains to scan the cross sections of bilateral middle cerebral arteries. Then middle cerebral artery specimens were removed for histology processing. LST1 presence was identified on magnetic resonance images, and lipid core areas were measured on the corresponding histology sections.Results—Total 76 middle cerebral artery locations were included for analysis. LST1 showed a high specificity (96.9%; 95% confidence interval, 82.0%–99.8%) but a low sensitivity (38.6%; 95% confidence interval, 24.7%–54.5%) for detecting lipid core of all areas. However, the sensitivity increased markedly (81.2%; 95% confidence interval, 53.7%–95.0%) when only lipid cores of area ≥0.80 mm2 were included. Mean lipid core area was 5× larger in those with presence of LST1 than in those without (1.63±1.18 mm2 versus 0.32±0.31 mm2; P=0.003).Conclusions—LST1 is a promising imaging biomarker of identifying intraplaque lipid core, which may be useful to distinguish intracranial atherosclerotic disease from other intracranial vasculopathies and to assess plaque vulnerability for risk stratification of patients with intracranial atherosclerotic disease. In vivo clinical studies are required to explore the correlation between LST1 and clinical outcomes of patients with intracranial atherosclerotic disease.

Perineural Spread in Noncutaneous Head and Neck Cancer: New Insights into an Old Problem.

Head and neck malignancies have the propensity to invade nerves. Perineural tumor invasion is common, with some series reporting rates of 30 to 100%. Squamous cell carcinoma and adenoid cystic carcinoma are the most commonly involved tumors. The most commonly involved nerves are the trigeminal (cranial nerve [CN] V) and facial (CN VII) and their branches. Neural spread away from a tumor is encountered less often and usually causes specific symptoms such as pain, muscle weakness, and atrophy, depending on the involved nerves. While clinical symptoms and physical examination may suggest the presence of neural invasion, specific imaging modalities such as fat-suppressed T1-weighted magnetic resonance images, should be utilized to identify perineural tumor spread in its early phases. Perineural tumor spread should be considered and addressed in the treatment planning of patients with head and neck or skull base cancers as it can influence the extent of surgery, and the dosage and fields of radiation therapy. In the current review, we discuss the clinical course of perineural tumor spread and its therapeutic implications.

Clinical Features and Prognosis of Sudden Sensorineural Hearing Loss Secondary to Intralabyrinthine Hemorrhage.

Background and ObjectivesA number of etiologies of idiopathic sudden sensorineural hearing loss (ISSNHL) have been proposed, including viral infection, vascular disturbance, and immune-mediated mechanisms. Intralabyrinthine hemorrhage (ILH) as a cause of SSNHL is extremely rare, and there have been no studies defining the characteristics of hearing impairment and prognosis in patients with ISSNHL due to ILH. This study aimed to investigate the difference in impaired hearing patterns and prognosis for hearing recovery between patients with ISSNHL due to ILH confirmed by magnetic resonance imaging (MRI) and sex- and age-matched patients with ISSNHL due to causes other than ILH.Subjects and MethodsWe compared the results of audiometry and MRI in 12 patients who had ILH on MRI (hemorrhage group) and in 23 sex- and age-matched controls without abnormal findings related to their hearing loss on MRI (non-hemorrhage group). Initial hearing impairment, progression, and recovery of hearing loss were compared between the two groups.ResultsA majority of patients (92%) in the hemorrhage group complained of dizziness. Initial hearing impairment was more frequent in the hemorrhage group than in the non-hemorrhage group (94.09±35.9 vs. 66.66±30.1, p-value=0.036). The final recovery threshold in the hemorrhage group was worse (78.19±46.26 vs. 37.17±31.96, p-value=0.014) than that in the non-hemorrhage group. In the hemorrhage group, hearing recovery seemed to occur less often at high frequencies (2,000, 4,000, and 8,000 Hz) than at low frequencies (250, 500, and 1,000 Hz).ConclusionsThe presence of ILH was associated with poor hearing prognosis and the occurrence of vertigo. The abrupt onset of hearing loss associated with vertigo and the presence of hyperresonance on fat-suppressed T1-weighted MRI images of labyrinthic fluid strongly suggests acute intralabyrinthine hemorrhage, and is predictive of considerable hearing impairment and poor prognosis.

Bone marrow lesions can be subtyped into groups with different clinical outcomes using two magnetic resonance imaging (MRI) sequences

IntroductionBone marrow lesions (BMLs) are features detected on MRI that are important in the pathogenesis of knee osteoarthritis. Since BMLs reflect heterogeneous pathologies this prospective cohort study examined whether BMLs detected using different MRI sequences are associated with distinct structural and clinical endpoints.MethodsA total of 297 community-based adults without knee pain were examined to identify BMLs visualised using three-dimensional T1-weighted gradient-echo fat-suppressed (T1-weighted sequences) fat-suppressed and fat-saturated FSE T2-weighted MRI sequences (T2-weighted sequences) at baseline. Cartilage volume was measured at baseline and follow-up, while incident knee pain was assessed at follow-up, an average of 2.3 years later.ResultsAt baseline, 46 BMLs were visualised in 39 participants. Of the 45 BMLs visualised on T2-weighted sequences, 34 (74 %) were also seen on T1-weighted sequences. One BML was seen on only T1-weighted sequences. Knees with BMLs visualised on both T1- and T2-weighted sequences had significantly higher medial tibial cartilage volume loss (45 mm3/annum, standard error of the mean (SEM) 14) than those with BMLs identified on only T2-weighted sequences (−13 mm3/annum SEM 19), after adjustment for age, gender and body mass index (p = 0.01). Incident knee pain was more likely in individuals with BMLs in the medial compartment visualised on both T1- and T2-weighted (eight participants, 53 %) compared to those with BMLs on only T2-weighted sequences (0 %) or no BMLs (76 participants, 31 %, p = 0.02).ConclusionsBMLs present on both T1- and T2-weighted MRI sequences were associated with increased medial tibial cartilage loss and incident knee pain compared with those BMLs seen only on T2-weighted sequences. This suggests that combining different MRI sequences may provide more informative targets in the prevention and treatment of knee osteoarthritis.

MRI characteristics of intraductal papilloma

Intraductal papilloma (IDP) is the most common pathological finding in women with pathological nipple discharge. Magnetic resonance imaging (MRI) has shown potential for characterizing breast tumors; however, MRI findings of IDPs are inconclusive, and certain diagnostic standards are lacking. To characterize the MRI features of IDP from a relatively large cohort. We retrospectively reviewed from 358 women with IDPs that were confirmed by histopathology. The clinical and imaging findings in 70 patients who underwent preoperative MRI were analyzed. MRI analyses included morphology and dynamic contrast-enhanced MRI. In 70 patients, 77 IDPs were detected on MRI, which revealed the following three patterns: small luminal mass papillomas; tumor-like papillomas; and MRI-occult papillomas. Fourteen IDPs involved small, oval, smooth, and contrast-enhanced masses at the posterior end of the enlarged duct corresponding to small luminal mass papillomas. Seven IDPs had large diameters along the direction of the breast duct, indicating the typical MRI findings for IDP. Of 47 tumor-like papillomas, 16 cases showed large diameters along the direction of the breast duct and close to the nipple (within 4 cm), seven cases resembled invasive breast cancer on MRI, and the remaining 24 were (24/47) undistinguishable from other benign breast diseases. Sixteen IDPs were MRI-occult papillomas that could not be distinguished from the surrounding benign disease by either contrast-enhanced MRI or fat-suppressed T2-weighted MRI. Small luminal mass papillomas or tumor-like papillomas with the largest diameters along the direction of the breast duct and close to the nipple (within 4 cm) might be the typical MRI findings for IDPs.

Feasibility of fat-saturated T2-weighted magnetic resonance imaging with slice encoding for metal artifact correction (SEMAC) at 3T

Background and PurposeFluid-sensitive MR imaging in postoperative evaluation is important, however, metallic artifacts is inevitable. The purpose is to investigate the feasibility of fat-saturated slice encoding for metal artifact correction (SEMAC)-corrected T2-weighted magnetic resonance (MR) at 3T in patients with spinal prostheses. MethodsFollowing institutional review board approval, 27 SEMAC-encoded spinal MRs between September 2012 and October 2013 in patients with spinal metallic prostheses were analyzed. The MR images were scanned on a 3T MR system including SEMAC-corrected and uncorrected fast spin echo (FSE) T2-weighted MR images with fat-saturation. Two musculoskeletal radiologists compared the image sets and qualitatively analyzed the images using a five-point scale in terms of artifact reduction around the prosthesis, visualization of the prosthesis and pedicle, and intervertebral neural foramina. Quantitative assessments were performed by calculating the ratio of signal intensity from the fixated vertebra and that from upper level vertebra. For statistical analyses, paired t-test was used. ResultsFat-saturated SEMAC-corrected T2-weighted MR images enabled significantly improved metallic artifact reduction (P<0.05). Quantitative evaluation of the signal intensity ratio of screw-fixated vertebra and upper level vertebra showed a significantly lower ratio on fat-saturated SEMAC images (P<0.05), however, the high signal intensity of signal pile-up could be not completely corrected. ConclusionSEMAC correction in fat-suppressed T2-weighted MR images can overcome the signal loss of metallic artifacts and provide improved delineation of the pedicle screw and peri-prosthetic region. Signal pile-up, however, could not be corrected completely, therefore readers should be cautious in the evaluation of marrow around the prosthesis.

Reliability of common clinical standing balance tests for people with hip osteoarthritis

Reliability of common clinical standing balance tests for people with hip osteoarthritis

Cervical spine fracture in advanced ankylosing spondylitis

A 51-year-old man with a 22-year history of ankylosing spondylitis who had been treated with nonsteroidal anti-inflammatory drugs and infliximab presented with severe posterior neck pain, which had been aggravated after he fell backwards 3 months earlier. The neurological examination was normal. Plain radiographs showed total ankylosis of the cervical spine and a C5 vertebral body fracture with anterior dislocation of C4 on C5 (Fig. 1). There were numerous thin pieces of foreign material along the spine (Fig. 1). The patient said he had undergone Korean traditional gold thread acupuncture therapy, which had not been effective. Gadolinium-enhanced fat-suppressed T1-weighted magnetic resonance imaging showed a recent compression fracture of the C5 vertebral body and resultant spinal cord compression (Fig. 2), as well as an old compression fracture of C7. For cervical spine fractures in ankylosing spondylitis, conservative treatment with gentle low-weight cervical traction can be performed initially, in the absence of a neurologic deficit. However, secondary neurological deterioration occurs frequently due to the delayed dislocation at the original fracture site, and surgical treatment is generally recommended. On surgical exploration of our patient, the C5 fracture was found to be stable and surgical f ixation was not done. The cervical spine is the most frequent site of acute spinal fracture in ankylosing spondylitis, particularly at C5-6 and C6-7. Since the cervical fractures in ankylosing spondylitis are usually unstable, with a high risk of neurological deficits, our patient was lucky not to have had any significant neurological complications. Figure 1 Plain radiograph shows total ankylosis of the cervical spine, a C5 vertebral body fracture with anterior dislocation of C4 on C5 (arrow), and numerous thin foreign bodies along the spine. Figure 2 Gadolinium-enhanced fat-suppressed T1-weighted magnetic resonance image shows a recent compression fracture of the C5 vertebral body (arrow) and resultant spinal cord compression, as well as an old compression fracture of C7.

Effect and Possible Mechanism of Muscle-Splitting Approach on Multifidus Muscle Injury and Atrophy After Posterior Lumbar Spine Surgery

Multifidus muscle injury and atrophy are common after posterior lumbar spine surgery and are associated with low back pain and functional disability. In theory, muscle-splitting and retraction with a self-retaining retractor are considered to be the major surgical factors. The effects and mechanisms of retraction have been well studied, but the exact effect and possible mechanism of injury and atrophy after muscle-splitting still lack experimental evidence. New Zealand White rabbits were divided into two groups. In group S, through a skin and lumbodorsal fascial incision, the bilateral multifidus muscles were dissected from the osseous structures in the standard fashion, while in group C, only a skin and lumbodorsal fascial incision was made. In each group, the multifidus muscle was evaluated by magnetic resonance imaging (MRI) and by histological analysis at three and forty-eight hours and at one, three, six, twelve, and twenty-four weeks after surgery. In group C, there was no injury or atrophy of the multifidus muscle after surgery. In group S, the mean T2-weighted signal intensity ratios of gross multifidus to psoas on fat-suppressed T2-weighted cross-sectional MRI scans peaked on week 3 and returned to baseline on week 24. Necrosis and inflammation of the multifidus muscle were evident and became more severe at one week. Fibrotic change was mainly seen at three and six weeks after surgery, and fatty degeneration mainly occurred at twelve and twenty-four weeks. Decreased acetylcholine activity and granular degeneration of the neuromuscular junction were observed at all follow-up times, and the numbers of degenerating neuromuscular junctions increased significantly with time after surgery. The splitting approach is an important cause of multifidus muscle injury and atrophy in posterior lumbar spine surgery. Denervation and disuse may be important factors in multifidus muscle atrophy in the splitting approach. This study provides a basis for the prevention of multifidus muscle injury and atrophy after posterior lumbar surgery.

Subdeltoid Lipoma Arborescens Combined With Rotator Cuff Tears

Lipoma arborescens, a rare benign intra-articular lesion, is characterized by lipomatous proliferation of the synovium in which the subsynovial tissue is replaced by mature adipocytes. Subdeltoid bursa is a rare location for lipoma arborescens, and only a few cases have been reported in the literature. This article reports 2 cases of subdeltoid lipoma arborescens combined with rotator cuff tears, and the possible relationships between subdeltoid lipoma arborescens and rotator cuff tears are discussed. The intra-articular villous proliferations on fat-suppressed T2-weighted magnetic resonance imaging appeared as yellowish-white lipomatous villous proliferations on arthroscopy, and finger-like lipomatous proliferation of the synovium, where the subsynovial connective tissue is replaced by mature adipocytes, on histology. Although further evidence would be necessary, the bony proliferations, in addition to bone-to-bone abrasion and inflammatory processes, may contribute to the relationship between subdeltoid lipoma arborescens and rotator cuff tears. Because this is a rare disease in a rare location, no established treatment guidelines are available for lipoma arborescens in subdeltoid bursa. For the current patients, arthroscopic excision of the lipoma arborescens and concomitant rotator cuff repair were prescribed after more than 6 months of conservative management. All patients had symptom relief and were satisfied with their results. Paying special attention to the radiologic and arthroscopic characteristics of the lipoma arborescens will help physicians and surgeons to achieve a more accurate diagnosis and effective treatment strategy, especially in patients with concomitant rotator cuff tears.

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.

Expanding Applications of the Subchondroplasty Procedure for the Treatment of Bone Marrow Lesions Observed on Magnetic Resonance Imaging

Increase in signal on T2-weighted fat-suppressed magnetic resonance imaging is referred to as a bone marrow lesion (BML). Although there is overlap with avascular necrosis, a subset of BMLs is unique and typically associated with overlying chondrosis in a high-load region of the joint. These lesions are often associated with localized knee pain. Several current studies demonstrate improvement in patient-reported outcomes after internally splinting the cancellous bone injuries of the femoral condyles and tibial plateaus with synthetic calcium phosphate bone substitute. As BMLs are often not isolated entities at the tibiofemoral articulation, it follows that the use of the same technique may be applied to the patellofemoral articulation when other pathologies are treated or used in other articulating areas of the knee, specifically the trochlea and patella. This article presents a proposed surgical technique to treat BMLs of these articulating areas.