Musculoskeletal tumors: how to use anatomic, functional, and metabolic MR techniques
Laura M Fayad, Michael A Jacobs, Xin Wang, John A Carrino, David A Bluemke, Laura M Fayad, Michael A Jacobs, Xin Wang, John A Carrino, David A Bluemke
Abstract
Although the function of magnetic resonance (MR) imaging in the evaluation of musculoskeletal tumors has traditionally been to help identify the extent of disease prior to treatment, its role continues to evolve as new techniques emerge. Conventional pulse sequences remain heavily used and useful, but with the advent of chemical shift imaging, diffusion-weighted imaging, perfusion imaging and MR spectroscopy, additional quantitative metrics have become available that may help expand the role of MR imaging to include detection, characterization, and reliable assessment of treatment response. This review discusses a multiparametric approach to the evaluation of musculoskeletal tumors, with a focus on the utility and potential added value of various pulse sequences in helping establish a diagnosis, assess pretreatment extent, and evaluate a tumor in the posttreatment setting for recurrence and treatment response.
© RSNA, 2012
Figures
Osteosarcoma of the right femur in a 15-year-old girl. (a) Sagittal T1-weighted MR image (370/10) shows complete replacement of normal fatty marrow signal intensity involving epiphysis and distal metadiaphysis of the right femur. Images obtained with nonenhanced T1-weighted sequence best depict contrast between marrow-replacing tumor and normal fatty marrow for accurately defining extent of the lesion. (b) Coronal fat-suppressed T2-weighted MR image (4000/66) shows perilesional bone marrow edema (short arrow), periosteal reaction (long arrows), and extension of tumor into adjacent soft tissues (arrowhead).
Osteosarcoma of the right femur in a 15-year-old girl. (a) Sagittal T1-weighted MR image (370/10) shows complete replacement of normal fatty marrow signal intensity involving epiphysis and distal metadiaphysis of the right femur. Images obtained with nonenhanced T1-weighted sequence best depict contrast between marrow-replacing tumor and normal fatty marrow for accurately defining extent of the lesion. (b) Coronal fat-suppressed T2-weighted MR image (4000/66) shows perilesional bone marrow edema (short arrow), periosteal reaction (long arrows), and extension of tumor into adjacent soft tissues (arrowhead).
Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (a) Axial T1-weighted MR image (466/16) shows lesion as fairly isointense to skeletal muscle with relatively subtle loss of normal muscle architecture. (b) Axial fat-suppressed T2-weighted MR image (3380/60) shows lesion to better advantage with good contrast resolution between mass and surrounding muscle. (c) ADC map shows low signal intensity in the mass and a range of ADCs from 0.9–1.1 × 10−3 mm2/sec. (d) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows discrete choline peak at 3.2 ppm (arrow). (e) Axial contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows avid early arterial enhancement in the lesion, in keeping with its malignant nature. (f) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5) obtained by subtracting nonenhanced from contrast-enhanced images shows enhancement throughout the mass. This sequence, in addition to the T1-weighted and fluid-sensitive sequences, also provides a good anatomic image for evaluating the lesion and its relationship to adjacent structures. Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (g) Axial T1-weighted MR image (466/16) shows that lesion remains subtle although decreased in size and of slightly altered signal intensity compared with its pretreatment appearance, now having slightly increased signal intensity relative to that of skeletal muscle. (h) Axial fat-suppressed T2-weighted MR image (3380/60) again shows interval decrease in size of the mass, now with more heterogeneous signal intensity, as compared with pretreatment image. Signal intensity changes after treatment are often identified and are not contributory toward interpretation of whether tumor has undergone treatment-related necrosis. (i) ADC map shows increased signal intensity with range of ADCs of 1.6–2.2 × 10−3 mm2/sec., a substantial difference compared with pretreatment images, suggesting interval treatment-related necrosis. (j) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows interval marked decrease in choline peak at 3.2 ppm (arrow), now very close to baseline noise level, also indicating that treatment-related necrosis has occurred. (k) Coronal contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows little if any arterial enhancement in the lesion, a substantial difference compared with the pretreatment image. (l) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5), obtained by subtracting unenhanced from contrast-enhanced images, now shows evidence of heterogeneous enhancement in the lesion. Final histologic examination after surgical resection revealed 90% treatment-related sclerosis, 5% necrosis, and 5% viable tumor. In this case, contrast enhancement represents, in part, treatment-related sclerosis (scar tissue) rather than viable tumor, but these two entities are indistinguishable on delayed contrast-enhanced studies, underscoring the need for perfusion examination when attempting to evaluate treatment response.
Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (a) Axial T1-weighted MR image (466/16) shows lesion as fairly isointense to skeletal muscle with relatively subtle loss of normal muscle architecture. (b) Axial fat-suppressed T2-weighted MR image (3380/60) shows lesion to better advantage with good contrast resolution between mass and surrounding muscle. (c) ADC map shows low signal intensity in the mass and a range of ADCs from 0.9–1.1 × 10−3 mm2/sec. (d) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows discrete choline peak at 3.2 ppm (arrow). (e) Axial contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows avid early arterial enhancement in the lesion, in keeping with its malignant nature. (f) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5) obtained by subtracting nonenhanced from contrast-enhanced images shows enhancement throughout the mass. This sequence, in addition to the T1-weighted and fluid-sensitive sequences, also provides a good anatomic image for evaluating the lesion and its relationship to adjacent structures. Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (g) Axial T1-weighted MR image (466/16) shows that lesion remains subtle although decreased in size and of slightly altered signal intensity compared with its pretreatment appearance, now having slightly increased signal intensity relative to that of skeletal muscle. (h) Axial fat-suppressed T2-weighted MR image (3380/60) again shows interval decrease in size of the mass, now with more heterogeneous signal intensity, as compared with pretreatment image. Signal intensity changes after treatment are often identified and are not contributory toward interpretation of whether tumor has undergone treatment-related necrosis. (i) ADC map shows increased signal intensity with range of ADCs of 1.6–2.2 × 10−3 mm2/sec., a substantial difference compared with pretreatment images, suggesting interval treatment-related necrosis. (j) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows interval marked decrease in choline peak at 3.2 ppm (arrow), now very close to baseline noise level, also indicating that treatment-related necrosis has occurred. (k) Coronal contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows little if any arterial enhancement in the lesion, a substantial difference compared with the pretreatment image. (l) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5), obtained by subtracting unenhanced from contrast-enhanced images, now shows evidence of heterogeneous enhancement in the lesion. Final histologic examination after surgical resection revealed 90% treatment-related sclerosis, 5% necrosis, and 5% viable tumor. In this case, contrast enhancement represents, in part, treatment-related sclerosis (scar tissue) rather than viable tumor, but these two entities are indistinguishable on delayed contrast-enhanced studies, underscoring the need for perfusion examination when attempting to evaluate treatment response.
Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (a) Axial T1-weighted MR image (466/16) shows lesion as fairly isointense to skeletal muscle with relatively subtle loss of normal muscle architecture. (b) Axial fat-suppressed T2-weighted MR image (3380/60) shows lesion to better advantage with good contrast resolution between mass and surrounding muscle. (c) ADC map shows low signal intensity in the mass and a range of ADCs from 0.9–1.1 × 10−3 mm2/sec. (d) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows discrete choline peak at 3.2 ppm (arrow). (e) Axial contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows avid early arterial enhancement in the lesion, in keeping with its malignant nature. (f) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5) obtained by subtracting nonenhanced from contrast-enhanced images shows enhancement throughout the mass. This sequence, in addition to the T1-weighted and fluid-sensitive sequences, also provides a good anatomic image for evaluating the lesion and its relationship to adjacent structures. Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (g) Axial T1-weighted MR image (466/16) shows that lesion remains subtle although decreased in size and of slightly altered signal intensity compared with its pretreatment appearance, now having slightly increased signal intensity relative to that of skeletal muscle. (h) Axial fat-suppressed T2-weighted MR image (3380/60) again shows interval decrease in size of the mass, now with more heterogeneous signal intensity, as compared with pretreatment image. Signal intensity changes after treatment are often identified and are not contributory toward interpretation of whether tumor has undergone treatment-related necrosis. (i) ADC map shows increased signal intensity with range of ADCs of 1.6–2.2 × 10−3 mm2/sec., a substantial difference compared with pretreatment images, suggesting interval treatment-related necrosis. (j) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows interval marked decrease in choline peak at 3.2 ppm (arrow), now very close to baseline noise level, also indicating that treatment-related necrosis has occurred. (k) Coronal contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows little if any arterial enhancement in the lesion, a substantial difference compared with the pretreatment image. (l) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5), obtained by subtracting unenhanced from contrast-enhanced images, now shows evidence of heterogeneous enhancement in the lesion. Final histologic examination after surgical resection revealed 90% treatment-related sclerosis, 5% necrosis, and 5% viable tumor. In this case, contrast enhancement represents, in part, treatment-related sclerosis (scar tissue) rather than viable tumor, but these two entities are indistinguishable on delayed contrast-enhanced studies, underscoring the need for perfusion examination when attempting to evaluate treatment response.
Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (a) Axial T1-weighted MR image (466/16) shows lesion as fairly isointense to skeletal muscle with relatively subtle loss of normal muscle architecture. (b) Axial fat-suppressed T2-weighted MR image (3380/60) shows lesion to better advantage with good contrast resolution between mass and surrounding muscle. (c) ADC map shows low signal intensity in the mass and a range of ADCs from 0.9–1.1 × 10−3 mm2/sec. (d) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows discrete choline peak at 3.2 ppm (arrow). (e) Axial contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows avid early arterial enhancement in the lesion, in keeping with its malignant nature. (f) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5) obtained by subtracting nonenhanced from contrast-enhanced images shows enhancement throughout the mass. This sequence, in addition to the T1-weighted and fluid-sensitive sequences, also provides a good anatomic image for evaluating the lesion and its relationship to adjacent structures. Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (g) Axial T1-weighted MR image (466/16) shows that lesion remains subtle although decreased in size and of slightly altered signal intensity compared with its pretreatment appearance, now having slightly increased signal intensity relative to that of skeletal muscle. (h) Axial fat-suppressed T2-weighted MR image (3380/60) again shows interval decrease in size of the mass, now with more heterogeneous signal intensity, as compared with pretreatment image. Signal intensity changes after treatment are often identified and are not contributory toward interpretation of whether tumor has undergone treatment-related necrosis. (i) ADC map shows increased signal intensity with range of ADCs of 1.6–2.2 × 10−3 mm2/sec., a substantial difference compared with pretreatment images, suggesting interval treatment-related necrosis. (j) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows interval marked decrease in choline peak at 3.2 ppm (arrow), now very close to baseline noise level, also indicating that treatment-related necrosis has occurred. (k) Coronal contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows little if any arterial enhancement in the lesion, a substantial difference compared with the pretreatment image. (l) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5), obtained by subtracting unenhanced from contrast-enhanced images, now shows evidence of heterogeneous enhancement in the lesion. Final histologic examination after surgical resection revealed 90% treatment-related sclerosis, 5% necrosis, and 5% viable tumor. In this case, contrast enhancement represents, in part, treatment-related sclerosis (scar tissue) rather than viable tumor, but these two entities are indistinguishable on delayed contrast-enhanced studies, underscoring the need for perfusion examination when attempting to evaluate treatment response.
Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (a) Axial T1-weighted MR image (466/16) shows lesion as fairly isointense to skeletal muscle with relatively subtle loss of normal muscle architecture. (b) Axial fat-suppressed T2-weighted MR image (3380/60) shows lesion to better advantage with good contrast resolution between mass and surrounding muscle. (c) ADC map shows low signal intensity in the mass and a range of ADCs from 0.9–1.1 × 10−3 mm2/sec. (d) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows discrete choline peak at 3.2 ppm (arrow). (e) Axial contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows avid early arterial enhancement in the lesion, in keeping with its malignant nature. (f) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5) obtained by subtracting nonenhanced from contrast-enhanced images shows enhancement throughout the mass. This sequence, in addition to the T1-weighted and fluid-sensitive sequences, also provides a good anatomic image for evaluating the lesion and its relationship to adjacent structures. Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (g) Axial T1-weighted MR image (466/16) shows that lesion remains subtle although decreased in size and of slightly altered signal intensity compared with its pretreatment appearance, now having slightly increased signal intensity relative to that of skeletal muscle. (h) Axial fat-suppressed T2-weighted MR image (3380/60) again shows interval decrease in size of the mass, now with more heterogeneous signal intensity, as compared with pretreatment image. Signal intensity changes after treatment are often identified and are not contributory toward interpretation of whether tumor has undergone treatment-related necrosis. (i) ADC map shows increased signal intensity with range of ADCs of 1.6–2.2 × 10−3 mm2/sec., a substantial difference compared with pretreatment images, suggesting interval treatment-related necrosis. (j) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows interval marked decrease in choline peak at 3.2 ppm (arrow), now very close to baseline noise level, also indicating that treatment-related necrosis has occurred. (k) Coronal contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows little if any arterial enhancement in the lesion, a substantial difference compared with the pretreatment image. (l) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5), obtained by subtracting unenhanced from contrast-enhanced images, now shows evidence of heterogeneous enhancement in the lesion. Final histologic examination after surgical resection revealed 90% treatment-related sclerosis, 5% necrosis, and 5% viable tumor. In this case, contrast enhancement represents, in part, treatment-related sclerosis (scar tissue) rather than viable tumor, but these two entities are indistinguishable on delayed contrast-enhanced studies, underscoring the need for perfusion examination when attempting to evaluate treatment response.
Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (a) Axial T1-weighted MR image (466/16) shows lesion as fairly isointense to skeletal muscle with relatively subtle loss of normal muscle architecture. (b) Axial fat-suppressed T2-weighted MR image (3380/60) shows lesion to better advantage with good contrast resolution between mass and surrounding muscle. (c) ADC map shows low signal intensity in the mass and a range of ADCs from 0.9–1.1 × 10−3 mm2/sec. (d) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows discrete choline peak at 3.2 ppm (arrow). (e) Axial contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows avid early arterial enhancement in the lesion, in keeping with its malignant nature. (f) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5) obtained by subtracting nonenhanced from contrast-enhanced images shows enhancement throughout the mass. This sequence, in addition to the T1-weighted and fluid-sensitive sequences, also provides a good anatomic image for evaluating the lesion and its relationship to adjacent structures. Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (g) Axial T1-weighted MR image (466/16) shows that lesion remains subtle although decreased in size and of slightly altered signal intensity compared with its pretreatment appearance, now having slightly increased signal intensity relative to that of skeletal muscle. (h) Axial fat-suppressed T2-weighted MR image (3380/60) again shows interval decrease in size of the mass, now with more heterogeneous signal intensity, as compared with pretreatment image. Signal intensity changes after treatment are often identified and are not contributory toward interpretation of whether tumor has undergone treatment-related necrosis. (i) ADC map shows increased signal intensity with range of ADCs of 1.6–2.2 × 10−3 mm2/sec., a substantial difference compared with pretreatment images, suggesting interval treatment-related necrosis. (j) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows interval marked decrease in choline peak at 3.2 ppm (arrow), now very close to baseline noise level, also indicating that treatment-related necrosis has occurred. (k) Coronal contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows little if any arterial enhancement in the lesion, a substantial difference compared with the pretreatment image. (l) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5), obtained by subtracting unenhanced from contrast-enhanced images, now shows evidence of heterogeneous enhancement in the lesion. Final histologic examination after surgical resection revealed 90% treatment-related sclerosis, 5% necrosis, and 5% viable tumor. In this case, contrast enhancement represents, in part, treatment-related sclerosis (scar tissue) rather than viable tumor, but these two entities are indistinguishable on delayed contrast-enhanced studies, underscoring the need for perfusion examination when attempting to evaluate treatment response.
Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (a) Axial T1-weighted MR image (466/16) shows lesion as fairly isointense to skeletal muscle with relatively subtle loss of normal muscle architecture. (b) Axial fat-suppressed T2-weighted MR image (3380/60) shows lesion to better advantage with good contrast resolution between mass and surrounding muscle. (c) ADC map shows low signal intensity in the mass and a range of ADCs from 0.9–1.1 × 10−3 mm2/sec. (d) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows discrete choline peak at 3.2 ppm (arrow). (e) Axial contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows avid early arterial enhancement in the lesion, in keeping with its malignant nature. (f) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5) obtained by subtracting nonenhanced from contrast-enhanced images shows enhancement throughout the mass. This sequence, in addition to the T1-weighted and fluid-sensitive sequences, also provides a good anatomic image for evaluating the lesion and its relationship to adjacent structures. Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (g) Axial T1-weighted MR image (466/16) shows that lesion remains subtle although decreased in size and of slightly altered signal intensity compared with its pretreatment appearance, now having slightly increased signal intensity relative to that of skeletal muscle. (h) Axial fat-suppressed T2-weighted MR image (3380/60) again shows interval decrease in size of the mass, now with more heterogeneous signal intensity, as compared with pretreatment image. Signal intensity changes after treatment are often identified and are not contributory toward interpretation of whether tumor has undergone treatment-related necrosis. (i) ADC map shows increased signal intensity with range of ADCs of 1.6–2.2 × 10−3 mm2/sec., a substantial difference compared with pretreatment images, suggesting interval treatment-related necrosis. (j) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows interval marked decrease in choline peak at 3.2 ppm (arrow), now very close to baseline noise level, also indicating that treatment-related necrosis has occurred. (k) Coronal contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows little if any arterial enhancement in the lesion, a substantial difference compared with the pretreatment image. (l) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5), obtained by subtracting unenhanced from contrast-enhanced images, now shows evidence of heterogeneous enhancement in the lesion. Final histologic examination after surgical resection revealed 90% treatment-related sclerosis, 5% necrosis, and 5% viable tumor. In this case, contrast enhancement represents, in part, treatment-related sclerosis (scar tissue) rather than viable tumor, but these two entities are indistinguishable on delayed contrast-enhanced studies, underscoring the need for perfusion examination when attempting to evaluate treatment response.
Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (a) Axial T1-weighted MR image (466/16) shows lesion as fairly isointense to skeletal muscle with relatively subtle loss of normal muscle architecture. (b) Axial fat-suppressed T2-weighted MR image (3380/60) shows lesion to better advantage with good contrast resolution between mass and surrounding muscle. (c) ADC map shows low signal intensity in the mass and a range of ADCs from 0.9–1.1 × 10−3 mm2/sec. (d) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows discrete choline peak at 3.2 ppm (arrow). (e) Axial contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows avid early arterial enhancement in the lesion, in keeping with its malignant nature. (f) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5) obtained by subtracting nonenhanced from contrast-enhanced images shows enhancement throughout the mass. This sequence, in addition to the T1-weighted and fluid-sensitive sequences, also provides a good anatomic image for evaluating the lesion and its relationship to adjacent structures. Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (g) Axial T1-weighted MR image (466/16) shows that lesion remains subtle although decreased in size and of slightly altered signal intensity compared with its pretreatment appearance, now having slightly increased signal intensity relative to that of skeletal muscle. (h) Axial fat-suppressed T2-weighted MR image (3380/60) again shows interval decrease in size of the mass, now with more heterogeneous signal intensity, as compared with pretreatment image. Signal intensity changes after treatment are often identified and are not contributory toward interpretation of whether tumor has undergone treatment-related necrosis. (i) ADC map shows increased signal intensity with range of ADCs of 1.6–2.2 × 10−3 mm2/sec., a substantial difference compared with pretreatment images, suggesting interval treatment-related necrosis. (j) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows interval marked decrease in choline peak at 3.2 ppm (arrow), now very close to baseline noise level, also indicating that treatment-related necrosis has occurred. (k) Coronal contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows little if any arterial enhancement in the lesion, a substantial difference compared with the pretreatment image. (l) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5), obtained by subtracting unenhanced from contrast-enhanced images, now shows evidence of heterogeneous enhancement in the lesion. Final histologic examination after surgical resection revealed 90% treatment-related sclerosis, 5% necrosis, and 5% viable tumor. In this case, contrast enhancement represents, in part, treatment-related sclerosis (scar tissue) rather than viable tumor, but these two entities are indistinguishable on delayed contrast-enhanced studies, underscoring the need for perfusion examination when attempting to evaluate treatment response.
Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (a) Axial T1-weighted MR image (466/16) shows lesion as fairly isointense to skeletal muscle with relatively subtle loss of normal muscle architecture. (b) Axial fat-suppressed T2-weighted MR image (3380/60) shows lesion to better advantage with good contrast resolution between mass and surrounding muscle. (c) ADC map shows low signal intensity in the mass and a range of ADCs from 0.9–1.1 × 10−3 mm2/sec. (d) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows discrete choline peak at 3.2 ppm (arrow). (e) Axial contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows avid early arterial enhancement in the lesion, in keeping with its malignant nature. (f) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5) obtained by subtracting nonenhanced from contrast-enhanced images shows enhancement throughout the mass. This sequence, in addition to the T1-weighted and fluid-sensitive sequences, also provides a good anatomic image for evaluating the lesion and its relationship to adjacent structures. Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (g) Axial T1-weighted MR image (466/16) shows that lesion remains subtle although decreased in size and of slightly altered signal intensity compared with its pretreatment appearance, now having slightly increased signal intensity relative to that of skeletal muscle. (h) Axial fat-suppressed T2-weighted MR image (3380/60) again shows interval decrease in size of the mass, now with more heterogeneous signal intensity, as compared with pretreatment image. Signal intensity changes after treatment are often identified and are not contributory toward interpretation of whether tumor has undergone treatment-related necrosis. (i) ADC map shows increased signal intensity with range of ADCs of 1.6–2.2 × 10−3 mm2/sec., a substantial difference compared with pretreatment images, suggesting interval treatment-related necrosis. (j) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows interval marked decrease in choline peak at 3.2 ppm (arrow), now very close to baseline noise level, also indicating that treatment-related necrosis has occurred. (k) Coronal contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows little if any arterial enhancement in the lesion, a substantial difference compared with the pretreatment image. (l) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5), obtained by subtracting unenhanced from contrast-enhanced images, now shows evidence of heterogeneous enhancement in the lesion. Final histologic examination after surgical resection revealed 90% treatment-related sclerosis, 5% necrosis, and 5% viable tumor. In this case, contrast enhancement represents, in part, treatment-related sclerosis (scar tissue) rather than viable tumor, but these two entities are indistinguishable on delayed contrast-enhanced studies, underscoring the need for perfusion examination when attempting to evaluate treatment response.
Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (a) Axial T1-weighted MR image (466/16) shows lesion as fairly isointense to skeletal muscle with relatively subtle loss of normal muscle architecture. (b) Axial fat-suppressed T2-weighted MR image (3380/60) shows lesion to better advantage with good contrast resolution between mass and surrounding muscle. (c) ADC map shows low signal intensity in the mass and a range of ADCs from 0.9–1.1 × 10−3 mm2/sec. (d) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows discrete choline peak at 3.2 ppm (arrow). (e) Axial contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows avid early arterial enhancement in the lesion, in keeping with its malignant nature. (f) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5) obtained by subtracting nonenhanced from contrast-enhanced images shows enhancement throughout the mass. This sequence, in addition to the T1-weighted and fluid-sensitive sequences, also provides a good anatomic image for evaluating the lesion and its relationship to adjacent structures. Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (g) Axial T1-weighted MR image (466/16) shows that lesion remains subtle although decreased in size and of slightly altered signal intensity compared with its pretreatment appearance, now having slightly increased signal intensity relative to that of skeletal muscle. (h) Axial fat-suppressed T2-weighted MR image (3380/60) again shows interval decrease in size of the mass, now with more heterogeneous signal intensity, as compared with pretreatment image. Signal intensity changes after treatment are often identified and are not contributory toward interpretation of whether tumor has undergone treatment-related necrosis. (i) ADC map shows increased signal intensity with range of ADCs of 1.6–2.2 × 10−3 mm2/sec., a substantial difference compared with pretreatment images, suggesting interval treatment-related necrosis. (j) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows interval marked decrease in choline peak at 3.2 ppm (arrow), now very close to baseline noise level, also indicating that treatment-related necrosis has occurred. (k) Coronal contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows little if any arterial enhancement in the lesion, a substantial difference compared with the pretreatment image. (l) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5), obtained by subtracting unenhanced from contrast-enhanced images, now shows evidence of heterogeneous enhancement in the lesion. Final histologic examination after surgical resection revealed 90% treatment-related sclerosis, 5% necrosis, and 5% viable tumor. In this case, contrast enhancement represents, in part, treatment-related sclerosis (scar tissue) rather than viable tumor, but these two entities are indistinguishable on delayed contrast-enhanced studies, underscoring the need for perfusion examination when attempting to evaluate treatment response.
Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (a) Axial T1-weighted MR image (466/16) shows lesion as fairly isointense to skeletal muscle with relatively subtle loss of normal muscle architecture. (b) Axial fat-suppressed T2-weighted MR image (3380/60) shows lesion to better advantage with good contrast resolution between mass and surrounding muscle. (c) ADC map shows low signal intensity in the mass and a range of ADCs from 0.9–1.1 × 10−3 mm2/sec. (d) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows discrete choline peak at 3.2 ppm (arrow). (e) Axial contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows avid early arterial enhancement in the lesion, in keeping with its malignant nature. (f) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5) obtained by subtracting nonenhanced from contrast-enhanced images shows enhancement throughout the mass. This sequence, in addition to the T1-weighted and fluid-sensitive sequences, also provides a good anatomic image for evaluating the lesion and its relationship to adjacent structures. Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (g) Axial T1-weighted MR image (466/16) shows that lesion remains subtle although decreased in size and of slightly altered signal intensity compared with its pretreatment appearance, now having slightly increased signal intensity relative to that of skeletal muscle. (h) Axial fat-suppressed T2-weighted MR image (3380/60) again shows interval decrease in size of the mass, now with more heterogeneous signal intensity, as compared with pretreatment image. Signal intensity changes after treatment are often identified and are not contributory toward interpretation of whether tumor has undergone treatment-related necrosis. (i) ADC map shows increased signal intensity with range of ADCs of 1.6–2.2 × 10−3 mm2/sec., a substantial difference compared with pretreatment images, suggesting interval treatment-related necrosis. (j) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows interval marked decrease in choline peak at 3.2 ppm (arrow), now very close to baseline noise level, also indicating that treatment-related necrosis has occurred. (k) Coronal contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows little if any arterial enhancement in the lesion, a substantial difference compared with the pretreatment image. (l) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5), obtained by subtracting unenhanced from contrast-enhanced images, now shows evidence of heterogeneous enhancement in the lesion. Final histologic examination after surgical resection revealed 90% treatment-related sclerosis, 5% necrosis, and 5% viable tumor. In this case, contrast enhancement represents, in part, treatment-related sclerosis (scar tissue) rather than viable tumor, but these two entities are indistinguishable on delayed contrast-enhanced studies, underscoring the need for perfusion examination when attempting to evaluate treatment response.
Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (a) Axial T1-weighted MR image (466/16) shows lesion as fairly isointense to skeletal muscle with relatively subtle loss of normal muscle architecture. (b) Axial fat-suppressed T2-weighted MR image (3380/60) shows lesion to better advantage with good contrast resolution between mass and surrounding muscle. (c) ADC map shows low signal intensity in the mass and a range of ADCs from 0.9–1.1 × 10−3 mm2/sec. (d) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows discrete choline peak at 3.2 ppm (arrow). (e) Axial contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows avid early arterial enhancement in the lesion, in keeping with its malignant nature. (f) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5) obtained by subtracting nonenhanced from contrast-enhanced images shows enhancement throughout the mass. This sequence, in addition to the T1-weighted and fluid-sensitive sequences, also provides a good anatomic image for evaluating the lesion and its relationship to adjacent structures. Pleomorphic rhabdomyosarcoma in an 81-year-old woman. Images were obtained (a–f) before and (g–l) after chemotherapy. (g) Axial T1-weighted MR image (466/16) shows that lesion remains subtle although decreased in size and of slightly altered signal intensity compared with its pretreatment appearance, now having slightly increased signal intensity relative to that of skeletal muscle. (h) Axial fat-suppressed T2-weighted MR image (3380/60) again shows interval decrease in size of the mass, now with more heterogeneous signal intensity, as compared with pretreatment image. Signal intensity changes after treatment are often identified and are not contributory toward interpretation of whether tumor has undergone treatment-related necrosis. (i) ADC map shows increased signal intensity with range of ADCs of 1.6–2.2 × 10−3 mm2/sec., a substantial difference compared with pretreatment images, suggesting interval treatment-related necrosis. (j) Proton MR spectroscopy (point-resolved spectroscopy, 2000/135) shows interval marked decrease in choline peak at 3.2 ppm (arrow), now very close to baseline noise level, also indicating that treatment-related necrosis has occurred. (k) Coronal contrast-enhanced MR image obtained at perfusion imaging (TWIST, 3.4/1.2) 20 seconds after contrast agent administration shows little if any arterial enhancement in the lesion, a substantial difference compared with the pretreatment image. (l) Coronal delayed contrast-enhanced MR image (volumetric interpolated breath-hold examination, 4.1/1.5), obtained by subtracting unenhanced from contrast-enhanced images, now shows evidence of heterogeneous enhancement in the lesion. Final histologic examination after surgical resection revealed 90% treatment-related sclerosis, 5% necrosis, and 5% viable tumor. In this case, contrast enhancement represents, in part, treatment-related sclerosis (scar tissue) rather than viable tumor, but these two entities are indistinguishable on delayed contrast-enhanced studies, underscoring the need for perfusion examination when attempting to evaluate treatment response.
Anatomic MR images in a 62-year-old man with metastatic disease show value of chemical shift imaging, as compared with delayed contrast-enhanced imaging. (a) Axial gradient-recalled-echo in-phase (left: 10/4.4) and opposed-phase (right: 10/2.2) MR images of the pelvis are shown. There is low signal intensity throughout the pelvic bones on the in-phase image, and it is difficult to distinguish normal hematopoietic marrow in pelvic bones from tumor infiltrating marrow on this image. Opposed-phase image clearly shows there is no decrease in signal intensity in right sacrum (short arrow) and left iliac bone (long arrow), representing areas of metastatic disease. Areas of signal drop-out (in left sacrum and right iliac bone) represent hematopoietic marrow reconversion. (b) Axial static delayed contrast-enhanced fat-suppressed T1-weighted image (10/4.9) obtained 1 minute after injection again shows tumor extent in pelvis (arrows), correlating well with the opposed-phase image.
Anatomic MR images in a 62-year-old man with metastatic disease show value of chemical shift imaging, as compared with delayed contrast-enhanced imaging. (a) Axial gradient-recalled-echo in-phase (left: 10/4.4) and opposed-phase (right: 10/2.2) MR images of the pelvis are shown. There is low signal intensity throughout the pelvic bones on the in-phase image, and it is difficult to distinguish normal hematopoietic marrow in pelvic bones from tumor infiltrating marrow on this image. Opposed-phase image clearly shows there is no decrease in signal intensity in right sacrum (short arrow) and left iliac bone (long arrow), representing areas of metastatic disease. Areas of signal drop-out (in left sacrum and right iliac bone) represent hematopoietic marrow reconversion. (b) Axial static delayed contrast-enhanced fat-suppressed T1-weighted image (10/4.9) obtained 1 minute after injection again shows tumor extent in pelvis (arrows), correlating well with the opposed-phase image.
Anatomic MR images in a 40-year-old woman with back pain show added value of chemical shift imaging in confirming neoplastic involvement of the marrow. (a) Sagittal T1-weighted MR image (450/15) shows multiple sites of abnormal signal intensity in the spine (short arrows) with fracture in the midthoracic spine (long arrow). (b) Sagittal gradient-recalled-echo in-phase (left: 10/4.4) and opposed-phase (right: 10/2.2) MR images show obvious areas of marrow-replacement, which were subsequently worked up and proved to be unsuspected metastatic breast cancer. Marrow replacement is identified quantitatively as absence of a notable decrease in signal intensity on opposed-phase, compared with in-phase, images—in this case, a decrease of less than 1%.
Anatomic MR images in a 40-year-old woman with back pain show added value of chemical shift imaging in confirming neoplastic involvement of the marrow. (a) Sagittal T1-weighted MR image (450/15) shows multiple sites of abnormal signal intensity in the spine (short arrows) with fracture in the midthoracic spine (long arrow). (b) Sagittal gradient-recalled-echo in-phase (left: 10/4.4) and opposed-phase (right: 10/2.2) MR images show obvious areas of marrow-replacement, which were subsequently worked up and proved to be unsuspected metastatic breast cancer. Marrow replacement is identified quantitatively as absence of a notable decrease in signal intensity on opposed-phase, compared with in-phase, images—in this case, a decrease of less than 1%.
Proton MR spectroscopy and functional imaging in a 61-year-old man with a soft-tissue mass. The patient was referred for biopsy due to suspicious imaging features. (a) Proton MR spectroscopic imaging (point-resolved spectroscopy, 2000/135) with single voxel (rectangular outline) in the heterogeneous mass shown on coronal STIR and contrast-enhanced MR images shows no detectable choline peak. (b) Multiple coronal MR images from a dynamic contrast-enhanced study obtained at 10, 30, 60 and 90 seconds after injection (TWIST, 3.4/1.2) and time-intensity curve show the mass to be markedly heterogeneous with aggressive features, including arterial enhancement. However, the contrast enhancement patterns of benign and malignant lesions can overlap. In this case, negligible choline content at MR spectroscopy was consistent with the histologic diagnosis of benign degenerated cystic schwannoma, which was confirmed after surgical resection.
Proton MR spectroscopy and functional imaging in a 61-year-old man with a soft-tissue mass. The patient was referred for biopsy due to suspicious imaging features. (a) Proton MR spectroscopic imaging (point-resolved spectroscopy, 2000/135) with single voxel (rectangular outline) in the heterogeneous mass shown on coronal STIR and contrast-enhanced MR images shows no detectable choline peak. (b) Multiple coronal MR images from a dynamic contrast-enhanced study obtained at 10, 30, 60 and 90 seconds after injection (TWIST, 3.4/1.2) and time-intensity curve show the mass to be markedly heterogeneous with aggressive features, including arterial enhancement. However, the contrast enhancement patterns of benign and malignant lesions can overlap. In this case, negligible choline content at MR spectroscopy was consistent with the histologic diagnosis of benign degenerated cystic schwannoma, which was confirmed after surgical resection.
Metastatic breast cancer in 53-year-old woman evaluated with whole-body MR imaging. Coronal whole-body fat-suppressed T2-weighted MR image (5000/87) shows several sites of metastatic disease in the left iliac and acetabular bones (short arrows) and liver (long arrows).
67-year-old woman with recurrent malignant fibrous histiocytoma. The advantages of functional techniques over anatomic imaging are highlighted. (a) Axial fat-suppressed T2 weighted image (TR/TE 3560/64) shows a relatively low to intermediate signal area of signal abnormality in the surgical bed (rectangle) with surrounding postoperative inflammation. (b) Axial T1 weighted image (TR/TE 580/20) shows architectural distortion suspicious for a recurrent mass. (c) ADC map shows a low signal intensity region with ADC value of 0.4, highly suspicious for recurrent tumor. (d) Finally, a contrast-enhanced coronal view from a DCE-MR imaging study (shown here at 20 seconds) shows the neovascularity of the recurrent tumor to best advantage.
67-year-old woman with recurrent malignant fibrous histiocytoma. The advantages of functional techniques over anatomic imaging are highlighted. (a) Axial fat-suppressed T2 weighted image (TR/TE 3560/64) shows a relatively low to intermediate signal area of signal abnormality in the surgical bed (rectangle) with surrounding postoperative inflammation. (b) Axial T1 weighted image (TR/TE 580/20) shows architectural distortion suspicious for a recurrent mass. (c) ADC map shows a low signal intensity region with ADC value of 0.4, highly suspicious for recurrent tumor. (d) Finally, a contrast-enhanced coronal view from a DCE-MR imaging study (shown here at 20 seconds) shows the neovascularity of the recurrent tumor to best advantage.
67-year-old woman with recurrent malignant fibrous histiocytoma. The advantages of functional techniques over anatomic imaging are highlighted. (a) Axial fat-suppressed T2 weighted image (TR/TE 3560/64) shows a relatively low to intermediate signal area of signal abnormality in the surgical bed (rectangle) with surrounding postoperative inflammation. (b) Axial T1 weighted image (TR/TE 580/20) shows architectural distortion suspicious for a recurrent mass. (c) ADC map shows a low signal intensity region with ADC value of 0.4, highly suspicious for recurrent tumor. (d) Finally, a contrast-enhanced coronal view from a DCE-MR imaging study (shown here at 20 seconds) shows the neovascularity of the recurrent tumor to best advantage.
67-year-old woman with recurrent malignant fibrous histiocytoma. The advantages of functional techniques over anatomic imaging are highlighted. (a) Axial fat-suppressed T2 weighted image (TR/TE 3560/64) shows a relatively low to intermediate signal area of signal abnormality in the surgical bed (rectangle) with surrounding postoperative inflammation. (b) Axial T1 weighted image (TR/TE 580/20) shows architectural distortion suspicious for a recurrent mass. (c) ADC map shows a low signal intensity region with ADC value of 0.4, highly suspicious for recurrent tumor. (d) Finally, a contrast-enhanced coronal view from a DCE-MR imaging study (shown here at 20 seconds) shows the neovascularity of the recurrent tumor to best advantage.
Source: PubMed