Femoral head osteonecrosis: volumetric MRI assessment and outcome

A Current Review in the Orthopedic Management of Osteonecrosis of the knee Secondary to Treatment of Pediatric Hematologic Malignancy

Acute Lymphoblastic Leukemia is the most prevalent pediatric hematologic malignancy. The treatment for this illness has advanced significantly, now touting a 90% cure rate. Although these patients often become disease free, treatment can leave devastating effects that last long after their disease burden is alleviated. A commonly experienced result of treatment is osteonecrosis (ON), often occurring in weight bearing joints. Uncertainty exists in the optimal treatment of this cohort of patients. In this review, we describe the etiology and suspected pathogenesis of ON, as well as treatment options described in the literature.

A Deep Learning Method for Quantification of Femoral Head Necrosis Based on Routine Hip MRI for Improved Surgical Decision Making

(1) Background: To evaluate the performance of a deep learning model to automatically segment femoral head necrosis (FHN) based on a standard 2D MRI sequence compared to manual segmentations for 3D quantification of FHN. (2) Methods: Twenty-six patients (thirty hips) with avascular necrosis underwent preoperative MR arthrography including a coronal 2D PD-w sequence and a 3D T1 VIBE sequence. Manual ground truth segmentations of the necrotic and unaffected bone were then performed by an expert reader to train a self-configuring nnU-Net model. Testing of the network performance was performed using a 5-fold cross-validation and Dice coefficients were calculated. In addition, performance across the three segmentations were compared using six parameters: volume of necrosis, volume of unaffected bone, percent of necrotic bone volume, surface of necrotic bone, unaffected femoral head surface, and percent of necrotic femoral head surface area. (3) Results: Comparison between the manual 3D and manual 2D segmentations as well as 2D with the automatic model yielded significant, strong correlations (Rp > 0.9) across all six parameters of necrosis. Dice coefficients between manual- and automated 2D segmentations of necrotic- and unaffected bone were 75 ± 15% and 91 ± 5%, respectively. None of the six parameters of FHN differed between the manual and automated 2D segmentations and showed strong correlations (Rp > 0.9). Necrotic volume and surface area showed significant differences (all p < 0.05) between early and advanced ARCO grading as opposed to the modified Kerboul angle, which was comparable between both groups (p > 0.05). (4) Conclusions: Our deep learning model to automatically segment femoral necrosis based on a routine hip MRI was highly accurate. Coupled with improved quantification for volume and surface area, as opposed to 2D angles, staging and course of treatment can become better tailored to patients with varying degrees of AVN.

The Role of Structural Deterioration and Biomechanical Changes of the Necrotic Lesion in Collapse Mechanism of Osteonecrosis of the Femoral Head

Osteonecrosis of the femoral head (ONFH) is a crippling disease which is due to a lack of effective therapeutic measures. Its natural progression is rapid, the internal bone structure of the femoral head changes dramatically, and the subsequent fractures and collapse cause severe hip pain and loss of hip function. Femoral head collapse is a critical turning point in the development of ONFH and is related to the prognosis of patients. Early prevention and intervention help to preserve the hip joint and delay femoral head collapse. However, the mechanism of collapse still needs to be further studied because it is affected by different complex factors. This review discusses the underlying causes of femoral head collapse from two aspects: structural degradation and regional changes of biomechanical properties in the necrotic femoral head.

Osteonecrosis in systemic lupus erythematosus: Systematic insight from the epidemiology, pathogenesis, diagnosis and management

Osteonecrosis (ON) is one of the serious and well recognized complicationscausing severe pain and disability in patients with systemic lupus erythematosus (SLE), and its manifestation and pathogenesis are only partially understood. This review provide an update of the recent progress in etiology, pathogenesis, diagnosis, and treatment of systemic lupus erythematosus related osteonecrosis (SLE-ON). Despite the concomitant use of corticosteroids, alcohol and obesity, the dysregulated immune micro-environment and the complex pathogenesis of SLE synergistically play important roles in the development of ON. Osteonecrosis of femoral head (ONFH) is the most often involved joint in SLE. The current classification and staging system of ONFH is based on imaging techniques, particularly relating to MRI and CT, for the identification and quantification of necrotic lesions. For SLE-ONFH patients, both SLE specific clinical symptoms and ONFH imaging findings should be comprehensively evaluated. Even though advances concerning bone grafting and arthroplasty procedures have resulted in improved clinical outcomes, early pharmacological treatment at the pre-collapse stage may prevent joint collapse and reduce the joint arthroplasty rate, and this needs to be accounted. Although some progress has been made, considerably more research is needed before we fully understand SLE-ONFH. Future treatments of SLE-ONFH may involve genetic or cell-based therapies that target potential biomarkers, and this will lead to effective measures for saving thefunction of hip joint and preventing osteonecrosis.

How does transtrochanteric anterior rotational osteotomy change the dynamic three-dimensional intact ratio in hips with osteonecrosis of the femoral head?

BACKGROUND

The intact ratio (the ratio of the intact area of the femoral head) on a two-dimensional anteroposterior radiograph is associated with the prognosis of hips with osteonecrosis of the femoral head after transtrochanteric anterior rotational osteotomy. However, changes of the three-dimensional intact ratio during dynamic weight-bearing activity and correlation of the three-dimensional intact ratio with clinical scores are still unknown.

METHODS

Kinematics of eight hips with osteonecrosis of the femoral head that underwent anterior rotational osteotomy were analyzed using image-matching techniques during chair-rising and squatting preoperatively and postoperatively. Two types of dynamic three-dimensional intact ratios were examined, including the lunate covered area (IR_LC) and in vivo peak contact force vector intersected area (IR_FV). The static three-dimensional intact ratio in each octant of the femoral head was also examined.

FINDINGS

The mean Harris hip score significantly improved from 67 preoperatively to 90 postoperatively. During chair-rising rising/squatting, the mean IR_LC and IR_FV significantly increased from 42%/41% and 7%/4% preoperatively, to 66%/65% and 79%/77% postoperatively, respectively. IR_LC significantly changed during the motion whereas substantial postoperative IR_FV was maintained throughout the motion. Additionally, Harris hip score and the static three-dimensional intact ratio in the superolateral regions had significant positive correlations with both IR_LC and IR_FV.

INTERPRETATION

Hip kinematics affected IR_LC but not IR_FV, which suggests that substantial intact bone occupies the region in which peak contact forces are applied during deep hip flexion. Additionally, improving intact ratio in the superolateral region led to improvements in both IR_LC and IR_FV with favorable clinical scores.

Biomechanical analysis of fibular graft techniques for nontraumatic osteonecrosis of the femoral head: a finite element analysis

Background

Free vascularized fibula graft (FVFG) techniques have most consistently demonstrated beneficial effects in young patients diagnosed with nontraumatic osteonecrosis of the femoral head (NONFH), and the core track technique (CTT) in particular is the most commonly used technique. As an alternative to CTT, the modified light bulb technique (LBT) has been reported to have a higher success rate. However, its biomechanical outcomes are poorly understood. This study aimed to compare the biomechanical properties of modified LBT with those of CTT in treating NONFH.

Methods

Two types (C1 and C2) of NONFH finite element models were established on the basis of a healthy subject and the Japanese Investigation Committee (JIC) classification system, and the CTT and LBT procedures were simulated in each type of model. The average von Mises stresses and stiffness of the proximal femur were calculated by applying a load of 250% of the body weight on the femoral head to simulate walking conditions. In addition, two patient-specific models were built and simulated under the same boundary conditions to further validate the LBT.

Results

In the healthy subject-derived models, both the LBT and CTT resulted in reduced stresses in the weight-bearing area, central femoral head, femoral neck, and trochanteric and subtrochanteric regions and increased structural stiffness after surgery. In the weight-bearing area, the CTT reduced the stress more than the LBT did (36.19% vs 31.45%) for type C1 NONFH and less than the LBT did (23.63% vs 26.76%) for type C2 NONFH. In the patient-specific models, the stiffness and stresses also increased and decreased, respectively, from before to after surgery, which is consistent with the results of healthy subject-derived models.

Conclusion

The biomechanical effects of the LBT and CTT differ by the JIC type of NONFH. In terms of preventing the collapse of the femoral head, the LBT may be more effective for JIC type C2 NONFH and may be a suitable alternative to the CTT, while for JIC type C1 NONFH, the CTT is still a better choice. Both techniques can improve the biomechanical properties of NONFH by reducing the proximal femoral stress and increasing the structural stiffness.

[Study on the distribution of necrotic tissue in steroid-induced osteonecrosis of femoral head patients based on three-dimensional reconstruction of CT]

OBJECTIVE

To observe the volume and distribution of necrotic tissue of femoral head in steroid-induced osteonecrosis of femoral head (SONFH) patients by three-dimensional reconstruction of CT.

METHODS

A clinical data of 25 patients with SONFH between September 2016 and December 2018 was analyzed. There were 22 males and 3 females, with an average age of 38.8 years (range, 20-63 years). The necrosis of the femoral head was in stage Ⅱ of Association Research Circulation Osseous (ARCO). The disease duration ranged from 3 to 18 months, with an average of 9.2 months. A three-dimensional reconstruction with CT data of SONFH patients were performed by Mimics Research 21.0 software and the femoral head was segmented into eight regions by 3-matic Research 13.0 software. The volume of necrotic tissue of the femoral head and the volume rate of necrotic tissue to femoral head were calculated and the distribution was also analyzed.

RESULTS

The three-dimensional digital model of the femoral head showed that the necrotic tissue of the femoral head was located above the anterior superior medial, and the area of the necrotic tissue was in a dome-like shape. The results showed that the necrotic tissue in the femoral head was mainly concentrated on the anterior superior internal area, the anterior superior outer area, and the posterior superior internal area. The volume of femoral head was (48 399.52±9 408.90) mm 3, and the volume of necrotic tissue was (20 917.08±6 566.94) mm 3, and the volume ratio of necrotic tissue to femoral head was 44.75%±15.72%. The proportion of necrotic volume in different regions was different, and the necrotic tissues were mainly distributed in the anterior superior internal area, the anterior superior outer area, and the posterior superior internal area.

CONCLUSION

The volume and distribution of necrotic tissue in femoral head can be evaluated quickly and intuitively by three-dimensional reconstruction of CT in Mimics software.

Comparison of sartorius muscle-pedicle and circumflex iliac deep bone flap grafts in the treatment of early non-traumatic osteonecrosis of femoral head in young adults

Objective

The aim of this study was to retrospectively compare and evaluate the midterm curative effect of two different bone flap grafts in the treatment of early non-traumatic osteonecrosis of the femoral head (ONFH).

Methods

A total of 180 patients (199 hips) with early non-traumatic ONFH received surgical treatment by sartorius muscle-pedicle bone flap graft (SMBF) (104 patients, 64 males and 40 females; mean age 34.67 ± 3.24 years) or circumflex iliac deep bone flap graft (CIDBF) (76 patients, 44 males and 32 females; mean age: 35.54 ± 3.37 years) from July 2004 to July 2009. The comparison between the groups was made with Harris score before and after surgery, length of incision, operative time, amount of bleeding, postoperative X-ray. Association Research Circulation Osseous (ARCO) staging was performed.

Results

The preoperative Harris hip score of two groups were 68.26 ± 1.26 and 69.35 ± 1.31, respectively. Patients' ARCO staging indicated 36 hips of stage IIa, 115 hips of stage IIb and 48 hips of stage IIc. The etiology of ONFH mainly including hormones (93 patients), alcohol (64 patients) and other (23 patients). The mean follow-up time of SMBF and CIDBF groups were (51.78 ± 2.35) and (52.73 ± 3.71) months, respectively. The time of removing sutures, operation time, amount of bleeding and length of incision in SMBF group were superior to those in the CIDBF group, and those differences between the SMBF and CIDBF groups were not significant (all p values > 0.28). The Harris score between the two groups was similar after operation and postoperative 12 month, and the difference was not statistically significant (p > 0.05), whereas the difference of the postoperative 24 and 48 months was statistically significant (p ˂ 0.05). X-ray analysis showed improvement of osteonecrosis in both two groups after surgery, and as time went on, the total hip amount decreased, the replacement amount increased.

Conclusion

Both bone flap grafts appear to be effective methods for treatment of early osteonecrosis of femoral head (ARCOⅡ), and the SMBF is a relatively simple technique and easy for mastering, and it is a reliable method for clinical application.

Level of evidence

Level III, Therapeutic Study.

BOLD-MRI early detect femoral head osteonecrosis following steroid-treated patients

The purpose of the study is to evaluate the feasibility of blood oxygenation level-dependent MRI (BOLD-MRI) to early detect the femoral head osteonecrosis (FHON). One hundred twelve patients were recruited who had received steroid treatment. The normal control group included 10 volunteers with 20 hips. MRI examinations were performed in all patients following up at 1, 4 to 5, 7 to 8, and 12 to 13 months after steroid therapy. With the section cross as the biggest lesion in coronal images, we set 6 regions of interest (ROIs) per section to analyze the morphological performance of routine MRI sequences and the differences of R2* values and their dynamic changes of BOLD-MRI between the control and the FHON group. A total of 15 hip joints were diagnosed with FHON. Seven right hips and 8 left hips were affected. In the first and second MRI examinations, the area of the lesion for both conventional MRI and BOLD-MRI R2* mapping was difficult to distinguish the lesion border. However, at the third and the fourth MRI examinations, some of the affected regions for R2* mapping were larger than those in conventional sequences for the same patient. BOLD-MRI has some significant advantages in early detecting FHON over conventional MRI techniques and it can be feasible noninvasive tool for detecting and evaluating FHON after steroid therapy.

S3-Guideline non-traumatic adult femoral head necrosis

INTRODUCTION

The treatment of adult non-traumatic avascular necrosis of the femoral head (AVN; N-ANFH) within an estimated incidence of 5000-7000 cases per annum in Germany remains a challenge. Risk factors include steroids, alcohol abuse, chemotherapy and immunosuppressive medication, but a genetic predisposition has been suggested. Early diagnosis of this often bilateral disease process is essential for successful conservative or joint preserving surgical management. In this review, we present the update German consensus S3 guideline "diagnosis and management for N-ANFH" as a concise summary.

MATERIALS AND METHODS

This systematic review is based on the published literature from January 1, 1970 to April 31, 2013 (German and English language). Inclusion criteria were systematic reviews, meta-analyses and relevant peer review publications. We identified a total of 3715 related publications, of which 422 were suitable according to the SIGN criteria, but only 159 fulfilled our inclusion criteria.

RESULTS AND CONCLUSIONS

Clinical suspicion of N-ANFH mandates radiographic evaluation. If radiographs are normal MRI scans are recommended, which should be evaluated according to the ARCO-classification. Differential diagnoses include transient osteoporosis, bone bruise, insufficiency fracture and destructive arthropathy. Untreated, subchondral fractures commonly occur within 2 years, during which the risk for contralateral involvement is high-thereafter unlikely. Conservative management with Ilomedin and Alendronat can be tried, but other pharmacological or physical treatments are inappropriate. No specific joint preserving procedure can be recommended, but core decompression should be considered in early stages if necrosis is <30 %. In ARCO stages IIIc or IV total hip arthroplasty (THA) should be contemplated, which offers similar outcome compared to osteoarthritis. Young age is the main risk factor for higher revision rates after THA for N-ANFH.

Osteonecrosis of the femoral head: using CT, MRI and gross specimen to characterize the location, shape and size of the lesion

OBJECTIVE

To investigate the accuracy of using CT and MRI to characterize lesions of osteonecrosis of the femoral head (ONFH).

METHODS

Coronal CT and MRI scans were performed on 30 femoral head specimens collected from 23 patients who had undertaken hip arthroplasty owing to ONFH. The results were compared with findings from coronal sectional gross specimens. Two radiologists independently measured the volume of necrotic lesions from CT and MR images using computer software, and the results were averaged. The volume of specimens' necrotic lesion was measured using the water displacement method.

RESULTS

There was a high degree of consistency between CT, MRI and the coronal sectional gross specimen on the location, shape and spatial structure of lesions. Differences of the lesion volume measured from CT and MR images were not statistically significant between two radiologists. The necrotic lesion volumes measured from CT and MR images and gross specimens were 22.07 ±5.35, 22.21 ± 5.15 and 21.12 ±4.96 cm(3), respectively, and the differences were not statistically significant (F = 0.396; p = 0.674).

CONCLUSION

For patients with ONFH in Association Research Circulation Osseous stage III or above, CT and MRI can accurately display the characterization of lesion.

ADVANCES IN KNOWLEDGE

The size and location of necrotic lesions are major factors associated with femoral head collapse. CT is superior to MRI in identifying subchondral fracture. CT can help diagnose and predict the prognosis of ONFH.

Vascularised greater trochanter bone graft, combined free iliac flap and impaction bone grafting for osteonecrosis of the femoral head

PURPOSE

To investigate the curative efficacy of osteonecrosis of the femoral head (ONFH) in a hip-preserving operative approach, by grafting a vascularized greater trochanter flap combined with a free iliac flap, in an attempt to seek an innovative approach for patients who suffered middle to late stage ONFH without total hip arthroplasty (THA) surgery.

METHOD

Our research included a total of 60 patients (66 hips) who accepted hip-preserving surgery by grafting a vascularized greater trochanter flap combined with a free iliac flap which was tightly filled by hammering because of ONFH (most were Association Research Circulation Osseous (ARCO) stage III patients) from January, 2006 to December, 2010. A Harris Hip Score was obtained during follow-ups, evaluating the clinical efficacy, X-rays were taken regularly for image assessing, and the SF-36 scale was used for estimating quality of life. Terminal observation time was considered when patients had symptom-dependant indications for performing another hip-preserving surgery or THA surgery.

RESULTS

Fifty-eight patients (64 hips) were eventually contacted by telephone for an out-patient clinic return visit, with a mean follow-up time of 35.8 months (varied from 12 months to 60 months), but two patients lost contact for various reasons. The demographic data were as follows: there were 16 ARCO IIIA cases, 22 ARCO IIIB cases, and 26 ARCO IIIC cases, respectively. Postoperative X-rays revealed a well-repaired necrotic area of the femoral head and improvement of femoral-acetabulum coverage. The last follow-up mean Harris Hip Score was 86.56 ± 7.38 (excellent results reached 87.50%), which were greatly improved compared to 50.95 ± 6.86 pre-operatively. Also the postoperative mean scores of all dimensions of the SF-36 scale were improved to some extent. Additionally the physical component summary (PSC) scores were enhanced from 42 ± 13 pre-operatively to 78 ± 11, while the postoperative mental component summary (MCS) scores (76 ± 11) largely increased in contrast to pre-operative scores (51 ± 10), with both target indices having statistical significance (p = 0.005, p = 0.01), signifying hugely improvement of the quality of life of the patients. A correlation was found between Harris Hip Score and all dimensions of SF-36 scale (r = 0.32-0.72), especially closely correlated with physical functioning (PF), role-physical (RP) and bodily pain (BP) in PCS aspect (r = 0.72, p < 0.01; r = 0.58, p < 0.01; r = 0.65, p < 0.01, respectively).

CONCLUSION

There is definite curative efficacy for the treatment of ONFH with an hip-preserving operative approach by grafting a vascularized greater trochanter flap combined with a free iliac flap which was tightly filled by hammering. This kind of operative approach reconstructs the biological stability of femoral head, which promotes repair of necrotic areas and indirectly preserves the femoral head of patients and a majority of hip function. It possesses vast clinical as well as practical significance, because the long-term efficacy can satisfy fundamental life requirements, especially for those young and middle-aged patients who suffer ONFH to avoid or put off the time of total hip arthroplasty (THA) surgery.

Accuracy and limitations of diagnostic methods for avascular necrosis of the hip

INTRODUCTION

Femoral head avascular necrosis (FHAVN) is the result of irreversible anoxia of the subchondral bone. The death of bone cells can cause articular collapse and pain, and in turn usually leads to degenerative arthritis. FHAVN is a common disorder, affecting mainly young male adults. Reliability, accuracy and prognostic value of any classification system are important in evaluation and treatment of FHAVN.

AREAS COVERED

Although in the past, scintigraphy and CT and more recently PET have been used for diagnosing AVN, currently the most important imaging methods included in the most widely used classification systems, consist of radiographs and magnetic resonance imaging (MRI). The latter is used in major classification systems for early detection (pre-radiographic stage) of FHAVN and for assessing lesion size and location before collapse of the articular surface occurs. The purpose of this review is to present the current data regarding the accuracy of the X-rays and MRI in diagnosing, monitoring and postoperative evaluation of FHAVN.

EXPERT OPINION

The author's opinion is that MRI may contribute to improve staging, investigate radiologically occult collapse, depict other causes of disability and pain, assess prognosis and evaluate treatment. Newer MRI techniques, such as diffusion-weighted imaging and perfusion imaging, have not yet provided additional and clinically useful information.

Are we evaluating osteonecrosis adequately?

PURPOSE

It is well recognised that to evaluate a patient with osteonecrosis of the femoral head (ONFH) adequately, it is necessary that the size of the infarct and the extent of femoral head joint involvement be indicated, in addition to the type or stage of the pathological process. The purpose of this study was to determine whether patients with ONFH are being evaluated adequately in studies published during the past 25 years and to see if any trends can be identified.

METHODS

Articles describing treatment of patients with ONFH, published between 1985 and 2011, were reviewed to determine the methods used to indicate the type and extent of pathology present on radiographs and magnetic resonance imaging (MRI) studies. The classification systems cited were identified and divided between those which indicated only the stage and those which indicated both stage and extent of involvement.

RESULTS

In 208 studies published between 1985 and 2011, specific classification systems were cited 237 times. During this period, non-quantitative systems, which only indicate stage, were cited 139 times (59 %) and quantitative systems, which indicate both stage and extent of involvement were cited 77 times (32 %). Between 2006 and 2011, non-quantitative systems were cited 30 times (48 %) and quantitative systems were cited 27 times (44 %).

CONCLUSIONS

During the past 25 years there has been a trend towards the use of more comprehensive and effective methods of evaluating patients with ONFH. However, during the past five years, approximately half of the published studies continued to use limited, non-quantitative methods of evaluation. This should be brought to the attention of the orthopaedic community. Future investigations and publications on ONFH should employ comprehensive methods of classification which include not only the stage of disease but also measurements of the size of the necrotic segment and the extent of femoral head and joint involvement.

Osteonecrosis in children after therapy for malignancy

OBJECTIVE

Osteonecrosis in the growing population of childhood cancer survivors results from disease and treatment. Imagers must be knowledgeable about patient groups at risk for its development, patterns of involvement and potential implications. This review will focus on implications of this potentially life-altering toxicity.

CONCLUSION

Childhood cancer survivors are at increased risk for developing osteonecrosis. Because osteonecrosis is often asymptomatic until late in the process, imaging is critical for its detection and characterization when interventions may be most effective to ameliorate its progression.

Transtrochanteric rotational osteotomy for nontraumatic osteonecrosis of the femoral head in young adults

Transtrochanteric rotational osteotomy (TRO) is a controversial procedure with reported inconsistent results. We reviewed 50 patients (60 hips) who underwent this procedure for extensive osteonecrosis of the femoral head, focusing on varization to determine its effectiveness as a head-preserving procedure in young adults. The mean age of the patients was 28 years (range, 18-46 years). Using the Ficat-Arlet classification, 40 hips had Stage II and 20 hips had Stage III involvement. According to the classification system of Shimizu et al., the extent of the lesions were Grade C in 54 hips and Grade B in six hips; the location of the lesions were Grade c in 56 hips and Grade b in four hips. Minimum followup was 18 months (mean, 84 months; range, 18-156 months). The mean preoperative Harris hip score was 44.7 points (range, 32-62 points) which improved to an average postoperative score of 80.1 points (range, 44-100 points) at the latest followup. Forty-four hips showed no radiographic evidence of progression of collapse. Ten hips showed progressive collapse, seven hips showed progressive varus deformity, three hips had stress fractures of the femoral neck, and one hip had infection. We believe TRO with varization is worth attempting for extensive osteonecrosis of the femoral head in young adults, although failures and complications are not uncommon.

LEVEL OF EVIDENCE

Level IV, case series. See the Guidelines for Authors for a complete description of levels of evidence.

Imaging of inflamed and vulnerable plaque in coronary arteries with 18F-FDG PET/CT in patients with suppression of myocardial uptake using a low-carbohydrate, high-fat preparation

PET/CT imaging with (18)F-FDG has been used to detect inflammation in carotid and aortic plaque; its use in detecting coronary plaque has been limited by avid (18)F-FDG uptake by the myocardium. We investigated whether (18)F-FDG PET/CT could be used to image inflammation in coronary arteries as a potential noninvasive method to detect vulnerable plaque.

METHODS

We retrospectively studied 32 patients treated for malignancy who underwent (18)F-FDG PET/CT and concomitant cardiac catheterization. As part of the recently described protocol, all patients were instructed to eat a low-carbohydrate, high-fat meal the night before and drink a vegetable oil drink the morning of the study. We reviewed the patients' baseline characteristics and their (18)F-FDG PET/CT scans for adequacy of myocardial uptake suppression and correlated the presence of angiographically apparent plaque with (18)F-FDG uptake in the major coronary arteries. Two independent observers assessed the angiographic images and (18)F-FDG PET scans.

RESULTS

A total of 95% of patients had 2 or more coronary disease risk factors, and 25% had unstable symptoms; 30% of index catheterizations resulted in intervention. In 20 of 32 patients (63%), myocardial suppression was good (12) or adequate (8). Inadequate suppression was due to self-reported dietary nonadherence. Patients with good, adequate, and poor suppression had maximal myocardial standardized uptake values of 2.8 +/- 0.7, 5.0 +/- 1.3, and 17.0 +/- 9.7, respectively. We identified (18)F-FDG uptake in 15 patients in 1 or more coronary segments. A trend to significance in correlation between presence of angiographic disease and signal in the vessel was observed (P = 0.07; 80 vessels examined). A total of 7 patients with significant coronary artery disease had aortic (18)F-FDG uptake.

CONCLUSION

In this retrospective study, we demonstrated the potential use of (18)F-FDG PET in imaging of inflammation in coronary arteries. The potential of (18)F-FDG PET is also being investigated in a prospective study.

Importance of sagittal MR imaging in nontraumatic femoral head osteonecrosis in children

BACKGROUND

In nontraumatic femoral head osteonecrosis, characterization of femoral head collapse is important in staging disease progression and planning treatment. Few prior studies have quantitatively compared the ability of sagittal and coronal MR images to detect femoral head collapse.

OBJECTIVE

We hypothesized that sagittal MR images show a greater degree and angular span of femoral head collapse than coronal images.

MATERIALS AND METHODS

We reviewed 38 hip MRI scans of nontraumatic femoral head osteonecrosis from 34 pediatric patients. In both sagittal and coronal images, the maximal extent and angular location along with the angular span of the femoral head collapse were measured. Differences were evaluated using a paired t-test. The extent of bone and cartilage loss from the femoral head was evaluated.

RESULTS

Sagittal MR images showed 29% maximal femoral head radius collapse, whereas coronal images showed 16% collapse (P<0.001). Sagittal images showed a larger angular span of collapse (115 degrees ) than coronal images (55 degrees , P<0.001). Sagittal images showed greater epiphyseal bone loss in the anterior than in the posterior portion (P<0.001), whereas coronal images did not show a significant difference in bone loss between the medial and lateral portion (P=0.32).

CONCLUSION

Sagittal images show greater femoral head collapse than coronal images in nontraumatic femoral head osteonecrosis.

Osteonecrosis of the femoral head: etiology, imaging and treatment

Osteonecrosis of the femoral head is a disabling clinical entity affecting young adults that usually leads to destruction of the hip joint. A high index of suspicion is necessary for the diagnosis due to the insidious onset of the bone infarcts and the lack of specific clinical signs at the early stages. Many etiology-associated factors have been identified reducing thus the number of idiopathic cases. A number of joint salvaging treatment options are available if early diagnosis can be achieved. MR imaging has been proved to be a highly accurate method both for early diagnosis and for staging of the disease. Replacement of the hip joint is the last resort for pain relief and function, although non-desirable because of the young age of the affected population.