Avascular necrosis of the hip: comparison of contrast-enhanced and nonenhanced MR imaging with histologic correlation. Work in progress.

Abstract

In 15 hips with typical signs of avascular necrosis of the femoral head on plain radiographs and magnetic resonance (MR) images, gadolinium-enhanced spin-echo and fat-suppressed MR images were obtained and compared with nonenhanced T1- and T2-weighted images. Both enhanced and nonenhanced areas were consistently detected in the abnormal femoral heads. Enhanced areas showed a low signal intensity (SI) on T1-weighted MR images obtained before contrast material was administered and an intermediate to high SI on T2-weighted images. Nonenhanced areas showed an SI either identical (pattern 1) or hypointense (pattern 2) to that of fat on both sequences. Histologic correlation (six resected femoral heads) helped confirm that enhanced and nonenhanced areas corresponded respectively to viable and necrotic tissue. In most cases, SI analysis of nonenhanced T1- and T2-weighted images allows the differentiation of hypervascularized viable tissue from hypovascularized necrotic tissue of the sequestrum.

MR signal intensity characteristics in LEgg-Calve-Perthes disease. Value of fat-suppressed (STIR) images and contrast-enhanced T1-weighted images

“…As the extent of necrosis of the epiphysis is one of the most important factors for the outcome of Legg‐Calvé‐Perthes disease, it is important to differentiate viable tissue from necrotic bone marrow. A strong correlation between contrast‐enhancing areas on MR and viable tissue is documented in the literature (22). With regard to the MR‐histopathological correlation found in animal experiments (17) and surgical specimens (11, 18, 22), histopathological findings may be represented by the signal intensity patterns that we found in our study.…”

“…A strong correlation between contrast‐enhancing areas on MR and viable tissue is documented in the literature (22). With regard to the MR‐histopathological correlation found in animal experiments (17) and surgical specimens (11, 18, 22), histopathological findings may be represented by the signal intensity patterns that we found in our study. It can be assumed that homogeneously isointense signal intensity on fat‐suppressed and T1‐weighted images represents healthy bone, whereas complete signal void on all images corresponds to advanced osseous necrosis, most likely with microfractures.…”

“…Nevertheless, reliable data on the histology in different phases of Legg‐Calvé‐Perthes disease is missing as biopsy, or even resection, of the femoral head is not performed in children with Legg‐Calvé‐Perthes disease. In adult osteonecrosis signal intensity changes on MR images are well correlated to histological findings as core biopsy or total hip replacement are commonly used surgical techniques (11, 18, 22).…”

Epiphyseal bone-marrow abnormalities and restitution in legg-calvé-perthes disease

“…Low signal areas develop a more intermediate signal on T1-weighted images and a high signal on T2-weighted images. Intermediate signal intensity on T1-and increased intensity on T2-weighted images, with enhancement on T1 after Gd, probably indicate hypervascular regenerative tissue (6,8,23). In the regenerative phase and early reconstruction phase, enhancement has been found (6).…”

Skeletal Scintigraphy in the Multimodality Assessment of Young Children With Acute Skeletal Symptoms

“…35,36 Absence of marrow enhancement after gadolinium helps to confirm avascularity. 37,38 MRI is very useful for showing abnormalities of the synovium and the growth cartilage of the epiphysis and physis. 39 -41 Perhaps because nourishment of the synovium Children with Acute Skeletal Symptoms and epiphyseal cartilage is by synovial fluid, overgrowth of these structures relative to the avascular epiphysis can occur.…”