Clinical and Quantitative MRI Perfusion Analysis of Osteoid Osteomas Before and After Microwave Ablation.

AIM: Evaluation of osteoid osteoma (OO) perfusion characteristics pre and post microwave ablation (MWA) using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with clinical follow-up. MATERIALS AND METHODS: Patients with OO underwent T1-weighted 3D DCE-MRI at 3.0T pre and post MWA. Signal intensity (SI) and perfusion of lesions was measured. Patients answered a questionnaire for clinical follow-up. RESULTS: A total of 24 patients were included (mean age of 28 years; nine females); 21 DCE-MRI datasets were of sufficient quality for analysis. The mean SI of lesions, plasma flow, volume of distribution and pain level all decreased statistically significantly after ablation. CONCLUSION: Quantitative MRI-perfusion analysis allows for objective treatment evaluation after MWA of OO, plasma flow and volume of distribution seem to be reliable indicators for successful thermoablation. MWA is an effective treatment option for OO with a low risk profile and significant pain reduction after treatment.

Osteoid osteoma--the CT vessel sign.

OBJECTIVE: To evaluate whether the presence of a feeding vessel in proximity to osteoid osteomas of long bones on multidetector CT (MDCT) can be an adjuvant clue for the diagnosis of osteoid osteoma. MATERIALS AND METHODS: Forty-nine CT scans of patients with radiological and clinical diagnosis of osteoid osteoma of long bones and a control group of 20 CT scans of patients with cortical-based lesions other then osteoid osteoma were analyzed. Two radiologists evaluated the CT images in consensus for the presence of a blood vessel in the same axial slices in which the nidus of osteoid osteoma was seen and to determine the incidence. RESULTS: In 39 cases (79.6%) of osteoid osteoma, a blood vessel either entered the nidus (23 patients) or was seen in proximity to it (16 patients). This was significantly different (P < 0.05) from the cortical-based lesions, in which only two CT scans (10%) showed a blood vessel in the lesion's proximity. CONCLUSION: In the majority of osteoid osteoma lesions in long bones, a blood vessel can be seen on MDCT either entering the nidus itself or in its proximity. The role of this vessel in the lesion pathogenesis and whether it improves diagnostic accuracy need further evaluation.

Histological study of osteoid osteoma's blood supply.

The osteoid osteoma is a painful lesion with a special predilection for the femur and tibia of young patients. Although the lesion has been described as richly innervated, its vascular supply has not been critically appraised to date in the pathology literature. To this end, we have undertaken a morphological study of 16 archival cases of osteoid osteoma, focusing primarily on the patterns of vascularization, utilizing traditional histological and immunohistochemical approaches. The study demonstrated that a prominent arterial and arteriolar blood supply was a constant finding within the various zones of soft tissues, skeletal muscle, and bone surrounding the nidus. It also showed that the caliber of the vessels underwent gradual attenuation throughout their centripetal course toward the nidus, where the vessels lost their muscularis as they merged into the capillary network of the nidus. Immunostaining with antibodies to neurofilament and S100 proteins revealed a pattern of innervation that was overall less exuberant than that described in some reports and that was virtually absent from the nidus. Taken together with data reported in the radiological literature, our findings lead us to wonder whether the osteoid osteoma may represent a response to the local stimulation of bony tissue by a primarily aberrant vasculature, a hypothesis that warrants further elucidation using state-of-the-art imaging approaches.

[Medullary osteoidosteoma of the os pisiforme]. / Medulläres Osteoidosteom des Os pisiforme.

A case of a medullary osteoidosteoma of the pisiforme bone is presented that appeared as a light bulb on MR-Angiography while causing diffuse hypointensity of the pisiforme bone and of the surrounding soft tissue on T1- and diffuse hyperintensity of these regions on T2-w and T1- w postcontrast images. Although not surprising according to the typical appearance of osteoidostomas on triple phase scintigraphy, the light bulb sign of osteoidosteomas on MRA has not yet been reported and familiarity with this findings may be of value in order to avoid their confusion with vascular lesions such as aneurysms or pseudoaneurysms during MR-angiography.

Doppler duplex color localization of osteoid osteomas.

We present two cases of osteoid osteoma in adolescent boys. The lesions were located in the proximal metaphysis of the right tibia and left femoral diaphysis respectively. Doppler duplex color study demonstrated clearly the highly vascular nidus and its feeding artery in one case and only the feeding artery in the second. We believe these are the first descriptions of osteoid osteomas assessed with Doppler duplex color, which was also used as guidance for the percutaneous localization and biopsy.

Osteoid osteoma of the spine: radiological aspects and value of arteriography. Four cases.

The authors present four cases of osteoid osteoma of the spine and review the usual clinical and paraclinical data leading to its diagnosis. The value of radionuclide bone scanning is emphasized: it supersedes the often disappointing radio-tomography and guides computerized tomography which, with modern scanners, virtually always demonstrates the lesion and locates it with accuracy. In the author's experience, spinal and spinal cord arteriography plays an important role: it identifies the radiculospinal vessels preoperatively and provides additional aetiological arguments based on the usual hypervascularity of osteoid osteomas and on the pain induced by injection of the feeding vessels. Data from the literature concerning the vascularization of the nidus suggest that treatment by embolization alone can be envisaged but must be demonstrated.

[Arterial DSA in malignant hypervascularized bone tumors]. / Arterielle DSA bei malignen hypervaskularisierten Knochentumoren.

In order to evaluate intra-arterial DSA in malignant bone tumors (osteosarcoma n = 2, aggressive osteoblastoma n = 1) three patients were examined angiographically including conventional arteriography and DSA. Compared with conventional angiograms DSA imaging demonstrated a reduced peripheral vascular information due to reduced spatial resolution. Advantages of DSA were an improved visualization of tumor blush and atypical venous return and in addition a reduction of volume rsp. concentration of the contrast material using a iodine concentration of 200 mg/ml for preoperative vascular mapping and of 300 mg/ml for diagnostic tumor imaging.

Adjuvant arterial embolization in the treatment of benign primary bone tumors in children.

This report presents an initial clinical experience with arterial embolization as adjuvent therapy in the surgical treatment of selected benign primary bone tumors in childhood. Embolization was dramatically effective in 4 children with spinal or pelvic vascular tumors. This technique facilitated local surgical resection and/or curettage. No child had evidence of local recurrence. Three of the 4 children had spinal cord or nerve root compression resulting in various degrees of paralysis prior to surgery. All treated patients had complete recovery from their paralysis. There were no complications of embolization or surgery. The treatment of benign primary bone tumors of the spine and pelvis is immeasurably improved by the adjuvant arterial embolization procedure. The immediate surgical treatment of these difficult tumors now becomes feasible with the greatly diminished blood flow resulting from embolization.

[Superselective angiographic finding in a case of osteom of the skull and the therapeutic consequences (author's transl)]. / Superselektiver arteriographischer Befund bei einem Osteom des Hirnschädels und der sich daraus ergebenden therapeutischen Konsequenz

The informational value and therapeutic application of the selective angiography is demonstrated in an osteoma fronto-temporo-parietal. The vessels feeding the tumor were identified and an artificial embolisation was performed.

Ultrastructure of osteoid osteoma.

The ultrastructure in five cases of osteoid osteoma is described. The osteoblasts generally had a morphology similar to that of normal osteoblasts with a few differences. They contained irregular indented nuclei, glycogen particles, abundant fine intracytoplasmic fibrils, and rare iron containing lysosomes. In several osteoblasts in two cases there were atypical mitochondria with a lobulated or "honeycomb" appearance. These atypical mitochondria were also observed in two osteoclasts; otherwise the cells resembled normal osteoclasts. Other cells present in osteoid osteoma besides osteocytes included osteoprogenitor cells resembling Scott type A and B cells and cells in transitional stages of differentiation. The osteoblasts most likely originated from Scott type A cells of preosteoblasts. The areas of mineralized matrix conformed to the morphology of coarse woven bone. Varying amounts of osteoid were noted. In two cases the osteoid contained, in addition to collagen, fine granular material, which probably represents polysaccharides. No nerve fibers were identified in the material studied. It is thought that osteoid osteoma is a benign neoplastic lesion. A case of osteoblastoma was studied for comparison; the osteoblastoma cells were found to have basically the same morphology as the cells in osteoid osteoma, including the atypical mitochondria. Our ultrastructural observations support the idea that osteoid osteoma and osteoblastoma are closely related lesions.