Aristeidis H. Zibis

MR imaging of transient osteoporosis of the hip: An update on 155 hip joints

PURPOSE Transient osteoporosis of the hip (TOH) presents with acute onset pain and bone marrow edema (BMe) on MR imaging. The purpose of this study is to revise the MR imaging characteristics of TOH by analyzing the data derived from 155 hip examinations. We also sought to explore the relationship between the duration of symptoms and the presence of sparing and subchondral fractures. MATERIALS AND METHODS MR images of 155 hips (141 TOH patients) were retrospectively evaluated for the presence of insufficiency fractures and the morphology of BMe. Sparing of the medial bone marrow of the femoral head was recorded together with demographic and clinical data. Progression to regional migratory osteoporosis (RMO) and postpartum cases were also recorded. RESULTS Our population consisted of 76.4% male and 23.6% female patients. RMO progression was recorded in 19.4% and 4 postpartum cases displayed bilateral disease. Sparing of the medial bone marrow was present at 87.7% of patients and disappeared as the disease progressed (P=0.005). BMe was restricted within the femoral head in 11.0%, extended to the femoral neck in 40% and to the femoral shaft in 49% of the cases studied. Subchondral fractures were present at 48.7% of the hips. CONCLUSION This study describes TOH patient characteristics, the MR imaging findings (BMe pattern, microfractures), their association with symptom duration and the chance of progressing to RMO.

Osteoid Osteoma of the Femoral Neck: Use of the Half-Moon Sign in MRI Diagnosis

OBJECTIVE Osteoid osteoma is a benign bone tumor that is commonly located in the proximal femur. Although CT is helpful in the diagnosis of osteoid osteoma, patients in whom the clinical presentation of the tumor is atypical are first referred to undergo MRI, which yields a high percentage of false-negative or inconclusive results. We sought to explore the association between a half-moon sign of bone marrow edema and the presence of osteoid osteoma of the femoral neck. SUBJECTS AND METHODS The MRI examinations of 11 consecutive patients with osteoid osteoma (group 1) were prospectively included in the study. In addition, 950 consecutive hip MRI examinations of 485 patients were retrospectively analyzed for the presence of bone marrow edema of the femoral neck, with 19 patients identified as having bone marrow edema resulting from causes other than osteoid osteoma (group 2). Patients in both study groups were evaluated for the presence of the half-moon sign. RESULTS The half-moon sign of bone marrow edema was significantly associated with the presence of osteoid osteoma (p < 0.0001), having been seen on the MR images of all 11 patients in group 1 and only one of 19 patients in group 2. MRI examination was therefore 94.7% specific and 100% sensitive for the detection of osteoid osteoma, with positive and negative predictive values of 91.7% and 100%, respectively. CONCLUSION The half-moon sign is an MRI finding that is highly specific and sensitive for an accurate diagnosis of osteoid osteoma of the femoral neck.

Normal Magnetic Resonance Imaging Anatomy of the Anterolateral Knee Ligament With a T2/T1-Weighted 3-Dimensional Sequence: A Feasibility Study

Purpose The anatomy of the lateral knee compartment has been recently further explored with description of the anterolateral knee ligament (ALL). The purpose of this study was to confirm the presence of ALL on cadaveric knees and to describe its normal anatomy in young healthy volunteers, utilizing a high-resolution 3-dimensional (3D) pulse sequence. Methods Dissection was performed on 9 cadaveric knees in order to confirm the presence of ALL. Conventional 2-dimensional sequences of 10 knees at 1.5 T and 10 knees at 3 T, with a slice thickness of 2-4 mm, were reviewed for the presence of ALL. A 3D T2/T1-weighted gradient echo sequence (constructive interference in steady state [CISS]), yielding in-plane resolution of 0.4 mm × 0.4 mm × 0.4 mm, was applied in 14 healthy volunteers (26 knees). All 3D images were manipulated using multiplanar reconstruction (MPR) and the presence and width of ALL were recorded. Results Cadaveric dissection disclosed the presence of ALL in 8 of 9 knees. Conventional knee MR imaging depicted ALL only on coronal images (18 of 20) whereas the CISS revealed ALL on 24 of 26 studied knees (92.3%). ALL has a mean thickness of 1.1 ± 0.27 mm measured on coronal MR images. Conclusions ALL can be thoroughly assessed in young healthy individuals with the use of high-resolution 3D MR imaging with MPR at 1.5 T.

Hydroxyapatite deposition disease around the hip: outcomes of CT-guided treatment.

PURPOSE Hydroxyapatite deposition disease (HADD) around the hip joint is a self-limiting condition usually treated conservatively. The aim of the present study is to directly compare the outcomes of CT-guided and conservative treatments in cases of refractory hip HADD. METHODS Two groups of patients with refractory hip HADD were prospectively constructed from a pool of 484 patients referred for greater trochanter pain syndrome, based on the presence of calcifications around the hip and the failure of conservative treatment. Study group included 22 hips, which underwent CT-guided barbotage and steroid injection treatment, whereas control group consisted of 28 hips that were treated conservatively. Evaluation of the outcome of both groups was performed over a one-year follow-up period with the use of a score measuring clinical improvement in terms of pain and functional impairment. RESULTS Three weeks after the initiation of treatment, study group exhibited significantly higher scores compared with the control group (P < 0.001). Improvement scores of the control group were similar to the study group after three months of treatment (P > 0.1). CONCLUSION CT-guided treatment provides relief of debilitating symptoms in the acute phase.

Imaging of Impingement Syndromes around the Hip Joint

Impingement syndromes are increasingly recognised as significant causes of hip pain and dysfunction. A broad spectrum of intraarticular and extraarticular conditions has been implicated in their pathophysiology. Physical examination is often inconclusive as clinical findings may be unclear or misleading, often simulating other disorders. With current improvements in imaging techniques and better understanding of hip impingement related pathomechanisms, these entities can be accurately diagnosed. In addition, preoperative imaging has allowed for targeted treatment planning. This article provides an overview of the various types of hip impingement, including femoroacetabular impingement, ischiofemoral impingement, snapping hip syndrome, greater trochanteric-pelvic and subspine impingement. Current literature data regarding their pathogenesis, clinical manifestation and imaging work-up are discussed.

Reply to “The Half-Moon Sign of the Femoral Neck Is Nonspecific for the Diagnosis of Osteoid Osteoma.”

AJR 2016; 206:W55 0361–803X/16/2063–W55

Magnetic resonance morphometry of the adult normal lumbar intervertebral space

PurposeThis study aims to: (a) quantify and evaluate normal relationships between neighboring spinal units using MR imaging indices, (b) propose an easy-to-apply-and-reproduce method of estimating the correct amount of distraction when surgically restoring a collapsed intervertebral disc, based on individualized measurements.MethodsThis is a retrospective cross-sectional MR imaging study of 119 adult subjects, aged 18–54, asymptomatic for low back pain. Each of the examinees should demonstrate two or more consecutive intervertebral discs classified as Pfirrmann grade I or II to be included. We measured and studied the relationships of disc height index, Dabbs index, Farfan index, disc convexity index and mean and posterior disc height per spinal level using multiple regression analysis. All measurements were tested for intra- and interobserver agreement by two raters.ResultsDHI, Dabbs, Farfan, and mean disc height had a statistically significant correlation with the spinal level and age. Our results were highly reproducible, with excellent inter- and intraobserver agreement and reliability between two raters (ICC = 0.992 and 0.994, respectively). Furthermore, we expressed each intervertebral space as a percentage of its adjacent space, introducing the coefficient α factor for every intervertebral space.ConclusionsOur results suggest that a normal values’ database to refer during preoperative planning of correction of a degenerated intervertebral disc is feasible. Our study offers new anatomical and radiological insight in terms of spinal measurements and their potential correlation with current surgical techniques. A new approach for calculating disc space as an expression of its adjacent disc has been introduced with various potential applications.

FETAL POSITION IN ALZHEIMER’S DISEASE. AN ANATOMIC BODY REMODELLING DUE TO RETROGENESIS

Is fetal position in Alzheimer’s disease a result of extensive muscle contraction, or a complete body and brain shutdown? Scientific community still tries to unveil the very nature of Alzheimer’s disease (AD) which is hidden in the mist of a blurred brain function. During the late stages of the disease, patients manifest a cluster of symptoms like increase in emotional needs, fears and anxieties, combined with an anatomic remodelling of their entire body and biomechanical shutdown. Weight loss, both fat and muscle deterioration, strength decrease and inability for the trunk to be self supported fill in an image which looks exactly like the fetal position. Although some may think that a complete physiological shutdown is in place, retrogenesis was introduced as a theory to demonstrate how individuals suffering RÉSUMÉ

Morel-Lavallée Lesions of the Knee: MRI Findings Compared With Cadaveric Study Findings

OBJECTIVE The purpose of this study is to describe the MRI findings and treatment decisions and outcome for Morel-Lavallée lesions (MLLs) of the knee and to investigate whether evidence exists to support an increased frequency of such lesions on the medial or lateral side by performing a cadaveric experiment. MATERIALS AND METHODS In a 4-year period, 24 MRI studies of 24 consecutive patients (16 male patients and eight female patients) with knee MLLs were retrospectively reviewed. Patient demographic characteristics, treatment decisions and outcome, and associated injuries were recorded. The location of the MLL was categorized as medial, lateral, or global. Lesions were categorized according to an established MRI classification. During the cadaveric experiment, the compartmental pressures of the medial or lateral aspect of the knee were monitored in 20 cadaveric knees. The chi-square test, t test, and Pearson correlation were used for statistical analysis. RESULTS MLLs were located medially in 16 patients, laterally in two patients, and globally in six patients. The medial location was significantly more common than a lateral or global location (p < 0.05). MLLs were classified as type I in 14 patients, type II in eight patients, and type III in two patients. MRI type was correlated with the chronicity of injury (r2 = 0.614; p = 0.0014). Fractures were the most common associated injuries, occurring in seven of 24 patients. In 17 patients, all of whom had conservatively treated type I or type II lesions, complete resolution of the MLL occurred. The maximum compartmental pressures were significantly higher on the lateral side than on the medial side (p < 0.0001). CONCLUSION Knee MLLs have a predilection for the medial side, which may be attributed to the lower resistance in this location, and they have variable patterns on MRI, which correlate with chronicity. Conservative treatment of type I and II lesions seems effective.

MRI of the hip: current concepts on bone marrow oedema

Bone marrow oedema (BME) is commonly found in hip MR imaging. BME is a nonspecific finding which can be related to a wide variety of diseases. However, there are cases where its existence or its pattern can narrow the differential or even point to a specific diagnosis. Therefore, deep understanding of its pathophysiology is of utmost importance for clinicians and radiologists in order to avoid diagnostic pitfalls. We hereby present currently established knowledge on BME related to adult hip pathology, aiming to raise physicians’ suspicion and to highlight that it is mandatory to combine specific imaging patterns with the history, clinical and laboratory findings in order to achieve accurate diagnosis.