Degenerative tears of the posterior horn of the medial meniscus: correlation between MRI findings and outcome following intra-articular steroid/bupivacaine injection of the knee.

AIM: To evaluate the response of symptomatic degenerative tears of the posterior horn of the medial meniscus to guided intra-articular knee steroid/bupivacaine injection and to correlate clinical outcomes with preprocedural findings at magnetic resonance imaging (MRI). MATERIALS AND METHODS: Sixty patients who had clinical and MRI evidence of a symptomatic degenerative tear of the posterior horn of the medial meniscus, isolated or accompanied by additional features of degenerative arthritis, who had failed conservative approaches (physiotherapy, non-steroidal anti-inflammatories, and 3 months rest/knee bracing) were included in the study. Patients underwent intra-articular knee steroid/bupivacaine injection and were followed clinically for a minimum of 6 months. Preprocedural MRI findings were correlated with duration of symptoms, clinical response to injection (recorded as complete, partial or no response) and duration of response to injection. RESULTS: Forty-nine of 60 patients (82%) reported an improvement in symptoms following guided intra-articular knee steroid/bupivacaine injection (complete: 25 patients (42%), partial: 24 (40%) patients). Improvement was sustained in 32 of 60 patients (53%) at follow-up. Thirteen of 18 patients (72%) who had an isolated degenerative tear of the posterior horn of the medial meniscus recorded a complete resolution of symptoms. This was sustained at follow-up in 10 patients (56%). CONCLUSION: Intra-articular steroid/bupivacaine knee joint injection reduced pain symptoms in the majority of patients (81.7%) with degenerative tears of the posterior horn of the medial meniscus, usually with a sustained response. Preprocedural MRI appearances correlate with response to injection. Patients with isolated tears are more likely to have a favourable outcome.

Differing MRI appearances of symptomatic proximal hamstring tendinopathy with ageing: a comparison of appearances in patients below and above 45 years.

AIM: To compare magnetic resonance imaging (MRI) appearances of symptomatic proximal hamstring tendinopathy (PHT) in younger (<45 years) and older (>45 years) patients. MATERIALS AND METHODS: MRI of patients with symptomatic PHT were reviewed and compared to asymptomatic age- and sex-matched controls. Appearances recorded were as: type 0, normal tendon; type I, intra-substance signal abnormality; type II, ischial bone and soft-tissue oedema with/without type I findings; type III, curvilinear fluid signal tearing with/without type II findings; type IV, bony avulsion. Disease pattern was compared between age groups using Fisher's exact test. RESULTS: Thirty-one symptomatic patients (18 male, 13 female; mean age 42 years) were identified. Imaging findings of 16 patients >45 years, 15 patients <45 were as follows: type 0 n=8, type I n=7, type II n=6, type III n=10, type IV n=0. Those >45 years tended to have type III tendinopathy, no examples of type III disease were found in patients <45 years (p<0.001). No significant difference in disease pattern was seen between males and females (p=0.39). Seven of 31 controls >45 years had type III findings and four controls <45 years had type I findings. CONCLUSION: MRI appearances of symptomatic PHT differ with age. Differences may reflect mechanism, whereby overuse-related micro-tearing of healthy tendons occurs in young patients versus degenerative tendinopathy in older patients. Abnormal tendon appearances in patients >45 years may or may not be symptomatic. In contrast, abnormalities identified in younger patients are generally symptomatic. These described differences are important in the primary diagnosis and may impact upon patient response to therapy.

Improved Detection of Anterior Circulation Occlusions: The "Delayed Vessel Sign" on Multiphase CT Angiography.

BACKGROUND AND PURPOSE: Multiphase CTA, a technique to dynamically assess the vasculature in acute ischemic stroke, was primarily developed to evaluate collateral filling. We have observed that it is also useful in identifying distal anterior circulation occlusions due to delayed anterior circulation opacification on multiphase CTA, an observation we term the "delayed vessel sign." We aimed to determine the usefulness of this sign by comparing multiphase CTA with single-phase CTA. MATERIALS AND METHODS: All 23 distal anterior circulation occlusions during a 2-year period were included. Ten M1-segment occlusions and 10 cases without a vessel occlusion were also included. All patients had follow-up imaging confirming the diagnosis. Initially, the noncontrast CT and first phase of the multiphase CTA study for each patient were blindly evaluated (2 neuroradiologists, 2 radiology trainees) for an anterior circulation occlusion. Readers' confidence, speed, and sensitivity of detection were recorded. Readers were then educated on the "delayed vessel sign," and each multiphase CTA study was re-examined for a vessel occlusion after at least 14 days. RESULTS: There was significant improvement in the sensitivity of detection of distal anterior circulation vessel occlusions (P < .001), overall confidence (P < .001), and time taken to interpret (P < .001) with multiphase CTA compared with single-phase CTA. Readers preferred MIP images compared with source images in >90% of cases. CONCLUSIONS: The delayed vessel sign is a reliable indicator of anterior circulation vessel occlusion, particularly in cases involving distal branches. Assessment of the later phases of multiphase CTA for the delayed vessel sign leads to a significant improvement in the speed and confidence of interpretation, compared with single-phase CTA.

Multifocal giant cell tumor of the tendon sheath: case report and literature review.

In this study, we present the rare case of a patient with a multifocal giant cell tumor of the tendon sheath occurring at three different localizations along the same tendon. We review radiographic, ultrasonographic, and magnetic resonance imaging findings, and discuss previously reported cases.

Transient osteoporosis of the hip and spontaneous osteonecrosis of the knee: a common aetiology?

INTRODUCTION: The aetiologies of transient osteoporosis of the hip (TOH) and spontaneous osteonecrosis of the knee (SONK) are still unknown. Both entities present with pain and extensive bone marrow oedema is seen on magnetic resonance imaging. METHODS AND MATERIALS: We describe a patient who presented with TOH and later also developed SONK. Initial magnetic resonance imaging findings of both the hip and the knee showed extensive bone marrow oedema and a subchondral fracture line suggesting that subchondral fractures might be of importance to the aetiology of both conditions. CONCLUSION: To our knowledge, this is the first case report that describes the occurrence of TOH and SONK in the same patient and introduces the possibility of a common aetiology.

Double-bundle depiction of the anterior cruciate ligament at 3 Tesla.

INTRODUCTION: Magnetic resonance imaging on 3 Tesla (3T MRI) with arthroscopic correlation has proven to adequately identify the anteromedial bundle (AMB) and posterolateral bundle (PLB) in cadaver knees. The purpose of this study was to describe the depiction of ACL bundle anatomy on 3T MRI in daily practice. METHODS: In a retrospective cohort study, we included 50 consecutive patients who underwent standard 3T MRI of the knee and had an intact ACL. Two musculoskeletal radiologists independently reviewed all scans for depiction of ACL bundle anatomy using standardized forms. Descriptive statistics were used. RESULTS: Twenty-three right knees (46%) and 27 left knees (54%) were included in the study. Mean age of the patients was 35 years (range 12 to 68 years); 37 patients were male (74%). ACL bundle anatomy was best depicted in the axial plane in 44 knees (88%) and in the coronal plane in six knees (12%). Two bundles were seen in 47 knees (94%). The AMB was completely seen in 45 knees (90%). The PLB was completely seen in 40 knees (80%). Both bundles were completely seen in 37 knees (76%). CONCLUSIONS: The double-bundle anatomy of the ACL is visualized in 94% of patients on 3T MRI. Because of potentially associated clinical benefits, we advocate to report separately on the anteromedial bundle and posterolateral bundle in case of anterior cruciate ligament injury of the knee.

Injectable corticosteroid preparations: an embolic risk assessment by static and dynamic microscopic analysis.

BACKGROUND AND PURPOSE: Transforaminal CS injections have been associated with severe adverse CNS events, including brain and spinal cord infarction. Our purpose was to describe the static and dynamic microscopic appearances of CS preparations, with an emphasis on their potential to cause adverse central nervous system events by embolic mechanisms during transforaminal injection. MATERIALS AND METHODS: Pharmaceutical preparations of nondilute injectable CSs were used after appropriate mixing: MPA (40 mg/mL), TA (40 mg/mL), and DSP (8 mg/2 mL). For dynamic imaging, a novel methodology was devised to replicate the flow of crystals within spinal cord arterioles. In addition, CS preparations were mixed with plasma to assess for changes in crystal size, morphology, and tendency to aggregate. RESULTS: The CS preparations MPA and TA are composed of crystals of varying sizes. MPA crystal size range was 0.4-26 µm (mean, 6.94 µm), TA crystal size range 0.5-110 µm (mean, 17.4 µm), and DSP did not contain any significant crystals or particles. There was no change in the crystal morphology or propensity to aggregate after mixing with local anesthetic. After mixing with plasma, the crystals also were unchanged; however, there was a significant reduction in the size of aggregates. On dynamic imaging, these aggregates were proved to maintain their integrity and to act as potential embolization agents. CONCLUSIONS: MPA and TA have a substantial risk of causing infarction by embolization if inadvertently injected intra-arterially at the time of TFESI. DSP is completely soluble and microscopically has no potential to obstruct arterioles. When performing cervical TFESI procedures, the administration of insoluble CSs should be avoided.

Three-dimensional magnetic resonance imaging analysis of hip morphology in the assessment of femoral acetabular impingement.

AIM: To determine a possible association between femoral-acetabular impingement (FAI) volume and the development of labral tear using a three-dimensional (3D) model reconstruction of the acetabulum and the femoral head. MATERIALS AND METHODS: Magnetic resonance arthrography images of the hip in 42 patients with pain and suspected labral tear were acquired using a 1.5T MRI machine. Using 3D analysis software, outlines of the acetabular cup and femoral head were drawn and 3D reconstruction obtained. To control for differences in patient size, ratios of acetabulum : femoral head volume (AFV) and acetabulum : femoral head surface area (AFA) were used for analysis. The association between volume of acetabulum : femoral head and FAI was investigated using ANOVA analysis. RESULTS: There were 19 men and 23 women with a mean age of 39 years (range 18-78 years). The average AFV was 0.64 (range 0.37-1.05, SD 0.16) and AFA was 0.73 (range 0.36-1.26, SD 0.23). Herniation pit was significantly associated with a small AFV. CONCLUSION: Femoral neck herniation pits are associated with a low AFV. Gross volume and surface area ratios do not appear to correlate with labral tears or cartilage loss. This technique will enable more advanced analysis of morphological variations associated with FAI.

A rare cause of calf swelling: the Morel-Lavallee lesion.

INTRODUCTION: Calf swelling is a common clinical presentation with a wide and varied differential diagnosis. The Morel-Lavallee is a rare cause of subcutaneous swelling, caused by post-traumatic shearing of the hypodermis from the underlying fascia. The potential space so created fills with blood, lymph and necrotic fat giving specific findings on MR evaluation. MATERIALS AND METHODS: A case of a 53-year-old man with calf swelling is presented, with clinical and MRI correlation. Treatment options and clinical course are discussed. CONCLUSION: The Morel-Lavallee lesion is a rare but important cause of calf swelling. MRI is the mainstay of diagnosis and treatment includes both surgical and minimally invasive modalities.

Metastatic adenocarcinoma of the lung mimicking mucoid degeneration of the anterior cruciate ligament.

We report a case of a 63-year-old male with known adenocarcinoma of the lung who presented with knee pain which was initially diagnosed as mucoid degeneration of the anterior cruciate ligament (ACL) on magnetic resonance imaging (MRI). Due to persistent knee pain an interval MRI was performed, followed by image guided biopsy which showed metastatic adenocarcinoma of the lung infiltrating the ACL. This is the first reported case in the literature of an intra-articular metastasis mimicking mucoid degeneration of the ACL.

Case report. Glioblastoma multiforme presenting as a haemorrhagic minimally enhancing mass of the trigone.

Tumours of the trigone are rare, representing less than 2.5% of all intracranial tumours. The most common cause in adults is a meningioma. Glioblastoma multiforme of the trigone is extremely rare, with only six cases reported in the literature. We present a case of a glioblastoma multiforme of the trigone presenting in a 57-year-old man with temporal lobe seizures. Imaging revealed a haemorrhagic minimally enhancing mass of the trigone. Histology showed a high-grade malignant glial-derived neoplasm of World Health Organization Grade IV.

MRI, CT, scintigraphic and histological features of a vanishing scapular eosinophilic granuloma.

INTRODUCTION: Vanishing bone lesions have been previously described in patients with eosinophilic granuloma. MATERIALS AND METHODS: We present the magnetic resonance imaging, computed tomography, scintigraphic and histological findings in a 26-year-old woman presenting with a painful scapular mass that subsequently completely resolved, compatible with the diagnosis of eosinophilic granuloma. CONCLUSION: Clinicians should be aware of the multimodality appearances and natural history of resolving eosinophilic granuloma.

MRI of injuries to the first interosseous cuneometatarsal (Lisfranc) ligament.

OBJECTIVE: The objective of this study was to assess the utility of MRI in diagnosing injury to the first interosseous cuneometatarsal (Lisfranc) ligament and to additionally determine the associated patterns of traumatic soft tissue and osseous injury. MATERIALS AND METHODS: Fifteen patients (16 feet) who were referred for MRI evaluation of the Lisfranc ligament, and had operative exploration or examination under anesthesia, were included for analysis. Standard non-contrast MRI foot imaging was performed in all cases. Evaluation of the following components was performed: the dorsal and plantar bundles of the Lisfranc ligament, the plantar tarsal metatarsal ligaments, soft tissue edema and fluid, and bone marrow edema and fractures. Surgical reports were regarded as the reference standard in all cases. RESULTS: Seven of 10 cases of grade 3 Lisfranc ligament injuries at surgery were correctly graded at MRI. No cases of surgically proven complete Lisfranc ligament tears (grade 3) were interpreted as normal at MRI. All Lisfranc ligament sprains (grade 2 or 3) at surgery were detected at MRI. Two of six cases reported as grade 1 injuries at MRI were normal at surgery. No cases of surgically proven normal or sprained Lisfranc ligaments were interpreted as grade 3 tears on MRI. Four of six of our cases of normal or sprained Lisfranc ligaments demonstrated fractures; while the minority of complete Lisfranc ligament tears (3/10) contained fractures. CONCLUSION: MRI is reasonably accurate at detecting traumatic injury to the Lisfranc ligament. However, in clinically suspected cases of traumatic Lisfranc ligament injury, true positive rate for sprain is low.