Genes Regulate Purkinje Cell Diversity in Cerebellar Development and Evolution.

Mammalian cerebellar development is thought to be influenced by distinct Purkinje cell (PC) subtypes. However, the degree of PC heterogeneity and the molecular drivers of this diversity have remained unclear, hindering efforts to manipulate PC diversification and assess its role in cerebellar development. Here, we demonstrate the critical role of genes in cerebellar development by regulating PC diversification.

Lumbar facet joint synovial cyst: percutaneous treatment with steroid injections and distention--clinical and imaging follow-up in 12 patients.

Purpose: To determine the imaging characteristics of lumbar facet joint synovial cysts after percutaneous treatment with steroid injections and distention of the cyst and to correlate these findings with the clinical outcome.

Materials And Methods: Clinical outcome and imaging findings were retrospectively studied in 12 patients (four men, eight women) aged 45-79 years (mean, 60 years) with a symptomatic lumbar facet joint synovial cyst treated with percutaneous steroid injections. At varying times after the procedure, patients were contacted for clinical follow-up, and repeat imaging was performed to verify the status of the cyst.

Arachnoiditis ossificans: MR imaging features in five patients.

Objective: The purpose of this article is to illustrate the appearance of arachnoiditis ossificans on MR imaging and discuss the implications this diagnosis has on treatment.

Conclusion: In patients with arachnoiditis ossificans, the MR imaging findings are of linear or masslike intrathecal lesions, which generally have some hyperintensity on T1- weighted sequences and are hyper- or hypointense on T2-weighted images, in the setting of arachnoiditis.

Pedicle marrow signal intensity changes in the lumbar spine: a manifestation of facet degenerative joint disease.

Objective: Signal intensity changes in lumbar pedicles, similar to those described in vertebral body endplates adjacent to degenerated discs, have been described as an ancillary sign of spondylolysis on MRI. The purpose of this study was to determine whether pedicle marrow signal intensity changes also occur in association with facet degenerative joint disease.

Design: Eighty-nine lumbar spine MRI examinations without spondylolysis were reviewed for marrow signal intensity changes in pedicles and vertebral bodies as well as for facet degenerative joint disease.

Association of posterior tibial tendon abnormalities with abnormal signal intensity in the sinus tarsi on MR imaging.

Objective: To evaluate the association of abnormal signal intensity within the sinus tarsi with abnormalities of the posterior tibial tendon (PTT) on MR imaging.

Design And Patients: Sinus tarsi abnormalities were identified on 30 ankle MR examinations in 29 patients. The PTT and anterior talofibular ligament were retrospectively analyzed for abnormalities in these same patients.

Identification of tibial stress fractures using therapeutic continuous ultrasound.

Study Design: One-group discriminant analysis.

Objective: To determine whether 1 MHz of continuous ultrasound can identify tibial stress fractures in subjects.

Background: Stress fractures can lead to loss of function or to more serious nonunion fractures.

Avulsion fracture of the base of the fifth metatarsal not seen on conventional radiography of the foot: the need for an additional projection.

Objective: To our knowledge, this article is the first to describe a series of patients with avulsion fractures of the base of the fifth metatarsal that were not seen on conventional radiography using the standard three views of the foot but that were seen on radiography of the ankle.

Conclusion: Because routine radiographs of the foot may fail to reveal an avulsion fracture of the base of the fifth metatarsal, an additional projection should be obtained to better assess this region in the symptomatic patient. The additional view should be an anteroposterior radiograph of the ankle that includes the base of the fifth metatarsal because this projection has been shown to help in the diagnosis of this avulsion fracture.

Fluoroscopy-guided sacroiliac joint injections.

The authors performed fluoroscopy-guided sacroiliac (SI) joint injections. With the patient prone and the x-ray tube perpendicular to the fluoroscopic table, the skin was marked over the distal 1 cm of the SI joint. With the tube angled 20 degrees - 25 degrees cephalad, a 22-gauge needle was inserted at the skin mark and advanced perpendicular to the fluoroscopic table toward the posterior joint.

Compartmental anatomy: relevance to staging and biopsy of musculoskeletal tumors.

A thorough understanding of compartmental anatomy is essential for accurate staging of a suspected musculoskeletal tumor with MR imaging and for avoiding potentially devastating biopsy-related complications. Imaging-guided, percutaneous needle biopsy is a safe and cost-effective technique but requires careful planning in conjunction with the surgeon who will perform the definitive surgery because it constitutes the final step in the staging process and the first step in surgical therapy.

Bone contusions of the posterior lip of the medial tibial plateau (contrecoup injury) and associated internal derangements of the knee at MR imaging.

Purpose: To determine if there are any predictable patterns of internal derangement associated with a bone contusion of the posterior lip of the medial tibial plateau at magnetic resonance (MR) imaging and to offer a biomechanical explanation for the findings.

Materials And Methods: A retrospective review of 215 consecutive MR examinations for knee trauma was conducted to identify contusions of the posterior lip of the medial tibial plateau. Any additional contusions and internal derangements were documented in the cases with these contusions.

Fatty marrow conversion of the proximal femoral metaphysis in osteonecrotic hips.

To determine whether fatty marrow conversion of the proximal femoral metaphysis is related to osteonecrosis of the femoral head using a marrow conversion index ([signal intensity of the proximal femoral metaphysis/signal intensity of the greater trochanter] x 100 in T1 weighted magnetic resonance images), a case control study was conducted on 42 osteonecrotic hips in 28 patients. The 28 patients (42 osteonecrotic hips) were matched with 84 control patients (84 normal hips) for gender, age (5-year range), and time of presentation (1-year range). The marrow conversion index was measured in each hip studied.

Muscle infarction in patients with diabetes mellitus: MR imaging findings.

Purpose: To describe the magnetic resonance (MR) imaging findings in diabetic patients with muscle infarction and to describe commonly associated clinical features.

Materials And Methods: The MR imaging studies of 21 patients with diabetic muscle infarction were reviewed retrospectively. Of the 21 patients, 12 were women, and nine were men; the mean age was 48 years (range, 30-77 years).

Magnetic resonance imaging of the wrist.

MR imaging of the wrist has the unique capability of simultaneously demonstrating bone and soft tissue structures. Its exquisite sensitivity for detecting bone marrow edema makes it and ideal screening tool for diagnosing radiographically occult osseous injuries and areas of AVN. This, together with its ability to provide a comprehensive, non-invasive assessment of the ligaments, tendons, nerves, and components of the TFC make MRI a very powerful tool for evaluating patients with wrist pain of uncertain etiology.

Anatomy and clinical significance of the horizontal cleft in the infrapatellar fat pad of the knee: MR imaging.

Objective: The purpose of this study was to determine the prevalence and nature of a horizontal cleft in the posterior aspect of Hoffa's infrapatellar fat pad and to show pathologic processes involving this cleft.

Materials And Methods: Fifty consecutive MR imaging examinations of the knee were evaluated for the presence and appearance of a cleft in the infrapatellar fat pad. Examples of abnormalities involving the cleft were collected from additional MR studies.

Age-related marrow conversion in the proximal metaphysis of the femur: evaluation with T1-weighted MR imaging.

Purpose: To determine the normal chronologic changes in fatty marrow conversion of the proximal femoral metaphysis at magnetic resonance (MR) imaging.

Materials And Methods: The "marrow conversion index," (signal intensity of the proximal femoral metaphysis divided by signal intensity of the greater trochanter) x 100, was measured in 182 hips of 91 patients who had no evidence of osteonecrosis or diseases involving bone marrow, no history of steroid treatment, and no other risk factors for osteonecrosis. The results were evaluated according to patient age and sex.

MRI of the foot and ankle.

The foot and ankle are among the hardest of all areas to image because of the complex three-dimensional anatomy. Magnetic resonance imaging (MRI), with its multiplanar capabilities, excellent soft-tissue contrast, ability to image bone marrow, noninvasiveness, and lack of ionizing radiation, has become a valuable tool in evaluating patients with foot and ankle problems. MRI is more specific than bone scintigraphy and provides more information than ultrasound and computed tomography.

Imaging of the knee. Current status.

This article reviews the variety of imaging modalities that are currently being used to evaluate the knee. Nuclear scintigraphy is discussed with emphasis on prosthesis abnormalities. Sonography is discussed with regard to the evaluation of popliteal masses.

Acutely injured knee: effect of MR imaging on diagnostic and therapeutic decisions.

Purpose: To assess the effect of knee magnetic resonance (MR) imaging on the diagnosis and management of acute knee injury.

Materials And Methods: Two orthopedic knee surgeons prospectively completed pre- and post-MR imaging questionnaires on 84 of 91 consecutive patients with acute knee injury. The pre- and post-MR imaging clinical diagnoses, certainty regarding these diagnoses, other diagnostic tests, and subjective impression of the usefulness of MR imaging were determined.

Fluoroscopically guided injections into the foot and ankle: localization of the source of pain as a guide to treatment--prospective study.

Purpose: To determine the value of injections of local anesthetic and steroids in the foot and ankle in localizing the source of pain and their effect on clinical confidence and decision making.

Materials And Methods: In 47 patients, fluoroscopically guided injections of local anesthetic and steroid into the foot and ankle were performed in 106 intra- and extraarticular sites. Questionnaires were completed by the referring surgeon before and after injections to evaluate the level of confidence with regard to the source of pain for each site injected and the proposed treatment plan.

MR imaging of ligamentous abnormalities of the elbow.

With high-resolution MR imaging, the collateral ligament of the elbow can be directly evaluated; thus ligamentous injuries can be detected, localized, and graded. The functional anatomy of the ligaments of the elbow is reviewed. The normal appearance of the ligaments on MR images as well as the clinical and MR imaging findings of medial and lateral collateral ligament injury are presented.

Acute knee trauma: how many plain film views are necessary for the initial examination?

Objective: To determine whether anteroposterior (AP) and lateral views of the knee are equivalent to four views in acute fracture detection.

Design: Three musculoskeletal radiologists retrospectively interpreted the plain film knee examinations of each patient, establishing ground truth for the presence or absence of a fracture. Cases were presented to four masked senior radiology residents twice--once as a two-view study and again as a four-view study--with 4 weeks separating the two reading sessions to minimize recall bias.

Plain film evaluation of degenerative disk disease at the lumbosacral junction.

Objective: Diagnosing degenerative disk disease (DDD) at the lumbosacral junction (LSJ) on plain films is often difficult, compared with other disk levels. The purpose of this study was to determine whether criteria for diagnosis of DDD at the LSJ can be established for plain films.

Design And Patients: We retrospectively reviewed 100 lumbar MRI scans of patients who also had lumbar plain films.

Radiographic measurements of dysplastic adult hips.

Hip dysplasia is a not uncommon feature in adults and can vary from subtle acetabular dysplasia to complex sequelae of developmental dysplasia of the hip. This review article describes the most useful radiographic measurements used to evaluate the adult hip. The frontal projection of the pelvis permits measurement of the center-edge angle (CE angle) and "horizontal toit externe" angle (HTE angle), both of which assess the superior coverage of the acetabulum.

Image-Guided Selective Nerve Blocks in the Spine.

Selective nerve block (SNB) in the spine is a diagnostic and therapeutic imaging procedure. It consists of placing a needle under fluoroscopic guidance in the epiradicular space, which is formed by extensions of the anterior and posterior epidural membranes. Injection of nonionic contrast will confirm the correct position of the needle.