Magnetic resonance imaging of the hip: anatomy and pathology

A pilot study to identify suitable MRI protocols for preoperative planning of total hip arthroplasty

PURPOSE

The purpose of this study is to identify suitable MRI sequences and evaluate the feasibility and performance of MRI for total hip arthroplasty (THA) preoperative planning.

METHOD

A multicentric pilot study was conducted to evaluate DP TSE and T1 GRE 3D sequences. High-resolution pelvis, hip, knee and ankle images were acquired. Protocols were optimised to enhance image quality (IQ) and reduce acquisition time to fit clinical practice. The final protocol was validated with 19 healthy volunteers with variable BMIs at 1.5 and 3 Tesla. Visual assessment was performed by five radiographers and radiologists using the ViewDEX software. Visual Grading Analysis (VGA), Intraclass Correlation Coefficient (ICC), Prevalence-adjusted and bias-adjusted kappa (PABAK) and Visual Grading Characteristics (VGC) were performed to analyse data.

RESULTS

VGA scores indicated that the optimised 3D DP TSE and 3D T1 GRE sequences at 3 T, as well as 3D DP TSE sequence at 1.5 T offer adequate IQ and allow a correct visualisation of the anatomy. Overall ICC analysis was moderate to good reliability at 0.749 (95 % CI 0.69-0.79) and increased from good to excellent at 0.846 (95 % CI 0.72-0.91) for DP at 3 T. PABAK shows fair agreement at 0.25 (95 % CI 0.227-0.273). VGC analysis showed that 3D DP TSE sequences performed statistically better than 3D T1 GRE at 1.5 and 3 T (p-value ≤ 0.05). Furthermore, 3 T sequences showed a statistically better performance compared to 1.5 T (p-value ≤ 0.05).

CONCLUSIONS

According to the results, 3D DP and T1 MRI sequences can be considered for preoperative planning for THA. Further research is required to emphasize the clinical validation of the results.

Vertebral Body Osteonecrosis Mimicking Malignant Disease on 18F-FDG PET

ABSTRACT

We report a case of vertebral osteonecrosis after chemotherapy in a 24-year-old man with non-Hodgkin lymphoma, with transient avidity on 18F-FDG PET initially misinterpreted as recurrent extranodal disease. The patient demonstrated a partial metabolic response on midtreatment restaging PET; however, posttreatment PET showed an increase in uptake in T4 and T5 vertebrae, interpreted as recurrent vertebral disease. Repeat PET performed 9 days later showed resolution of thoracic vertebral uptake without interval treatment. On follow-up PET study, thoracic vertebrae demonstrated photopenia with sclerosis on CT, concerning for osteonecrosis. MRI features were concordant with this diagnosis.

Particularities on Anatomy and Normal Postsurgical Appearances of the Hip

Detailed knowledge of anatomy helps to understand pathologic processes. This article focuses on the anatomy and functionality of the hip, with emphasis on recently studied concepts and anatomic features that have an association with the development of symptoms. The most common anatomic variants posing a challenge for diagnosis and other common findings in asymptomatic patients are reviewed. Good understanding of the different surgical procedures helps in providing as much information as possible to guarantee a favorable outcome, improving prognosis. We review what are the commonly expected postsurgical appearances and the most common postsurgical complications.

Isolated Gluteus Maximus Tear of a Middle-Aged Fitness Coach; A Case Report

Background: Injuries of the hip extensors are not uncommon, with those of the hamstrings being frequent among athletes. On the contrary, isolated injuries of the gluteus maximus muscle have been barely reported in the literature. Case Report: We present a case of a 63-year-old male water aerobics trainer with an acute tear of the right gluteus maximus tendon and describe the clinical presentation, imaging studies, surgical treatment, and functional outcome one year after surgery.

How to Report: Hip MRI

Writing a good magnetic resonance imaging (MRI) hip report requires a sound understanding of hip anatomy, imaging, and related pathologies. The structures of the hip most prone to pathology are the articular surfaces, labrum, subchondral bone, and gluteal tendons. Particular attention should be paid to abnormal hip morphology that is relatively common and can manifest as internal or external hip derangement. It is essential to appreciate and report the specific features of each pathology that carry clinical significance to aid patient management. This article is aimed at trainee radiologists and those less experienced with reporting hip MRI, focusing on the essential features to comment on and providing examples of terminology to use and MR images to illustrate these features.