Comparative study of whole-body MRI and bone scintigraphy for the detection of bone metastases.

AIM: To assess and compare the diagnostic accuracy of whole-body magnetic resonance imaging (MRI) and bone scintigraphy in the detection of metastases to bone. MATERIAL AND METHODS: Forty randomly selected patients with known malignant tumours were prospectively studied using bone scintigraphy and whole-body MRI. Two patients were excluded. Symptoms of bone metastasis were present in 29 (76%) patients and absent in nine (24%). Findings were classified into four categories according to the probability of bone metastasis: (1) negative, (2) probably negative, (3) probably positive, and (4) positive. Diagnostic accuracy was determined according to the area under the receiver operating characteristic (ROC) curve. The definitive diagnosis was reached using other imaging techniques, biopsy, or 12 months clinical follow-up. RESULTS: Metastases were present in 18 patients. The sensitivity, specificity, and diagnostic accuracy were 94, 90, and 92%, respectively, for whole-body MRI and 72, 75, and 74%, respectively, for bone scintigraphy. Diagnostic accuracy measured by the area under the ROC curve was significantly higher for whole-body MRI (96%) than for bone scintigraphy (77%; p<0.05). Interobserver agreement measured by the kappa index was significantly higher for whole-body MRI (0.895) than for bone scintigraphy (0.524; p<0.05). Whole-body MRI detected lesions in tissues other than bone in 17 (45%) patients. CONCLUSIONS: Whole-body MRI is more accurate and more objective than bone scintigraphy for the detection of bone metastases. Whole-body MRI can also detect lesions in tissues other than bone.

Diagnostic value of apparent diffusion coefficients to differentiate benign from malignant vertebral bone marrow lesions.

AIM: The aim of this study is to evaluate the value of the apparent diffusion coefficient (ADC) obtained in diffusion-weighted (DW) MR sequences for the differentiation between malignant and benign bone marrow lesions. METHOD: Forty-five patients with altered signal intensity vertebral bodies on conventional MR sequences were included. The cause of altered signal intensity was benign osteoporotic collapse in 16, acute neoplastic infiltration in 15, and infectious processes in 14; based on plain-film, CT, bone scintigraphy, conventional MR studies, biopsy or follow-up. All patients underwent isotropic DW MR images (multi-shot EPI, b values of 0 and 500 s/mm(2)). Signal intensity at DW MR images was evaluated and ADC values were calculated and compared between malignancy, benign edema and infectious spondylitis. RESULTS: Acute malignant fractures were hyperintense compared to normal vertebral bodies on the diffusion-weighted sequence, except in one patient with sclerotic metastases. Mean ADC value from benign edema (1.9+/-0.39 x 10(-3) mm(2)/s) was significantly (p<0.0001) higher than untreated metastasic lesions (0.9+/-1.3 x 10(-3)mm (2)/s). Mean ADC value of infectious spondilytis (0.96+/-0.49 x 10(-3) mm(2)/s) was not statistically (p>0.05) different from untreated metastasic lesions. ADC value was low (0.75 x 10(-3) mm(2)/s) in one case of subacute benign fracture. CONCLUSIONS: ADC values are a useful complementary tool to characterize bone marrow lesions, in order to distinguish acute benign fractures from malignant or infectious bone lesions. However, ADC values are not valuable in order to differentiate malignancy from infection.

[Comparison between intratumoral and peritumoral injection of radiotracer for locating and biopsying the sentinel lymph node in nonpalpable breast cancer]. / Comparación entre la inyección intratumoral y peritumoral del radiotrazador para la localización y biopsia del ganglio centinela en cáncer de mama no palpable.

OBJECTIVE: To determine whether there are differences in the technical efficacy in detecting and biopsying the sentinel node after intratumoral or peritumoral administration of the radiotracer in patients with nonpalpable early-stage breast cancer. MATERIAL AND METHODS: This prospective, randomized study included 80 patients with nonpalpable breast cancer without axillary adenopathies who were scheduled for primary surgical treatment. Patients were randomized to one of two groups: the INTRA group (intratumoral radiotracer administration, n=35) or the PERI group (peritumoral radiotracer administration, n=45). Patients with suspicious axillary lymph nodes at clinical or ultrasonographic examination that had positive results after fine-needle aspiration cytology were excluded. RESULTS: The rates of sentinel node detection were 97.1% (34/35) for intratumoral injection and 84.4% (38/45) for peritumoral injection. Radiotracer migration failure occurred in 8 cases (one in the INTRA group and 7 in the PERI group). The sentinel node was detected in an extra-axillary location in 21.9% of cases (11/59 in the INTRA group and 16/64 in the PERI group). CONCLUSIONS: Our study found no statistically significant differences in the detection rates of axillary or extra-axillary sentinel lymph nodes between the two groups; however, we observed greater technical efficacy with intratumoral radiotracer administration.

[Diffusion-weighted whole-body MRI (virtual PET) in screening for osseous metastases]. / Resonancia magnética de todo el cuerpo con técnica de difusión (PET virtual) para el cribado de las metástasis óseas.

OBJECTIVE: To present our preliminary experience in whole-body MRI with an added diffusion-weighted sequence in screening for osseous metastases. MATERIAL AND METHODS: 24 patients with malignant neoplasms underwent bone scintigraphy and whole-body MRI with the addition of a diffusion-weighted sequence. Whole-body MRI was performed on a 1.5 T unit using a three-station protocol; coronal T1-weighted FSE and STIR sequences and sagittal T1-weighted FSE of the spine were acquired. A diffusion-weighted sequence (b: 600 s/mm2) was added in the axial plane at five different stations and iconographic presentation in coronal-plane reconstructions with contrast inversion was used to obtain an image similar to that provided by PET (virtual PET). The findings at bone scintigraphy (BS) and MRI were compared for the presence of osseous metastases, evaluating the results for each patient both globally and for different osseous regions. Metastatic lesions were confirmed by biopsy or by six to eight months' follow-up. RESULTS: Globally, whole-body MRI with diffusion-weighted sequences was superior to bone scintigraphy, with a sensitivity of 100% (BS 71%), specificity 90% (BS 80%), and reliability 96% (BS 75%). In the evaluation by osseous region, the results of MRI were also better than those of bone scintigraphy: sensitivity 96% (BS 52%). In the diffusion-weighted sequence, lytic metastases were hyperintense in all cases, with an apparent diffusion coefficient (ADC) value higher than normal bone but lower than lesions with acute edema of benign etiology. Whole-body MRI also revealed unknown extraosseous findings related to the tumors and extraosseous metastases in 42% of the patients. CONCLUSIONS: Whole-body MRI with an added diffusion-weighted sequence is an efficacious method of detecting osseous metastases and is more reliable than bone scintigraphy. Moreover, whole-body MRI provides information about extraosseous lesions. Lytic metastases are hyperintense in diffusion-weighted sequences and have a lower ADC than benign edema.

Synovial chondromatosis of the temporomandibular joint: CT and MRI findings.

We report a rare case of synovial chondromatosis of the temporomandibular joint (TMJ) in a 31-year-old man. CT examination showed a mixed soft tissue mass with small calcifications near the right TMJ joint space. MR images revealed a heterogeneous mass on the different sequences and, after contrast administration, originating in the right TMJ. Cytology showed chondroid cellularity. The lesion was surgically removed and final histological study demonstrated the diagnosis of a synovial chondromatosis. We highlight the importance of the complementary findings from CT and MR, especially the important specific feature described for TMJ synovial chondromatosis related to the mixed density within the mass, in order to perform an accurate preoperative diagnosis whenever there is an absence of ossified loose bodies.

Breast hemangioma mimicking carcinoma.

Breast hemangiomas are rare, and usually appear as well-delimited round or oval nodules at mammography. We report a case of a woman with a breast hemangioma, which mammographic features simulated malignancy, and present its pathologic correlation. Hemangiomas are benign vascular tumors that are rarely present in the breast, usually found incidentally on microscopy of biopsy material for other. They are occasionally detected by mammography, presenting as well-delimited round, lobulated nodules, sometimes with calcifications. We present the mammographic findings and pathologic correlation in a case of breast hemangioma with an atypical radiological manifestation, simulating a carcinoma. To our knowledge, this is the first reported case with these radiologic characteristics.