Các dấu hiệu MRI u mô mềm

Tăng tín hiệu T1Không có xóa mỡ Axial MR images demonstrate a ruptured epidermal inclusion cyst within the dorsal subcutaneous tissues near the olecranon.. Tăng tín hiệu T1Có xóa mỡ Most

Các dấu hiệu MRI u mô

mềm

Jeff Stevens, MD Ricardo Garza-Gongora, MD Linda Parman, MD Connie So, MD

https://dps2016.rsna.org/exhibit/?exhibit=MK252-ED-X

Mở đầu

• Soft tissue tumors of the extremities are commonly encountered,

though remain a challenging diagnosis

• • While radiography and CT still serve a vital role in the evaluation of

soft tissue tumors, MRI, with its improved soft tissue contrast, often

provides much greater detail of these lesions

• • A specific diagnosis often remains unobtainable.

• – A correct histological diagnosis is only reached in one-third of cases

• • Still, certain soft tissue tumors have specific characteristics or

“signatures” which are highly suggestive and occasionally diagnostic of a certain histological diagnosis precluding the need for biopsy

Điểm chính

• To briefly discuss technical considerations important in MR evaluation

of soft tissue tumors

• • To provide a radiologic depiction of certain soft tissue tumors which demonstrate specific MR signal characteristics or “signatures”, which may allow for diagnosis without biopsy

• • In most cases, a specific diagnosis is not obtainable by imaging

alone This exhibit will also provide a systematic approach to narrow the differential diagnosis for those lesions which remain

indeterminate

T2FS - highlight areas of increased signal intensity (SI)/edema within or around

the mass

Post-contrast imaging often required for evaluation of mass lesions These are often performed with T1 weighting

and fat saturation

• • Preferred small FOV targeting the lesion

• Axial plane used to determine compartmental anatomy and presence/extent of invasion of adjacent structures

• Lesions should be imaged in at least two longitudinal planes –this depends on area of interest

• Sagittal with anterior or posterior masses and coronal with medial or lateral masses

• Used to delineate cystic from solid masses

• Plays important role in targeting soft tissue nodules in cystic or hemorrhagic lesions

• Enhancement cannot reliably distinguish benign or malignant lesions

Lưu ý kỹ thuật

Includes cysts and “cyst-like” lesions, which can be both

benign and malignant Further characterized following administration of IV gadolinium

Lưu đồ: Tổn thương tăng tín hiệu T1

Tăng tín hiệu T1

Không có xóa mỡ

Substances which demonstrate T1 shortening but do not lose SI following fat

suppression include proteinaceous fluid, methemoglobin, and melanin

Two lesions, one of which is T1 hyperintense without significant fat suppression This represents methemoglobin in hematomas Differing signal intensity of these lesions is related to different ages of blood products

Tăng tín hiệu T1

Không có xóa mỡ

Axial MR images demonstrate a (ruptured) epidermal inclusion cyst within the dorsal subcutaneous tissues near the olecranon Mass demonstrates slightly increased T1 signal characteristics relative to muscle Contrast-enhanced T1-weighted MR image shows only minimal peripheral enhancement.

Lưu đồ: Tổn thương tăng tín hiệu T1

Tăng tín hiệu T1

Có xóa mỡ

Most T1 hyperintense lesions which demonstrate fat suppression are lipomas.

Identical to adjacent fat on T1WI Uniform, homogeneous fat suppression on T1FS

low T1 SI Biopsy was consistent with well- differentiated liposarcoma.

Lưu đồ: Tổn thương giảm tín hiệu T2

• Giant Cell Tumor of the Tendon Sheath

• Pigmented Villonodular Synovitis

Giảm tín hiệu T2

Có đóng vôi

Sagittal T1 and T2FS MR images of the knee demonstrate tumoral calcinosis posterior and inferior to the knee

joint Peri-articular masses are hypointense on both T1 and T2 weighted imaging Sagittal CT image better

demonstrates the flocculent calcifications seen in tumoral calcinosis.

Giảm tín hiệu T2

U tế bào khổng lồ bao gân

Location can greatly aid lesion characterization of T2 hypointense lesions Notice

lesion’s location relative to the flexor tendon of the index finger

Low T2 signal intensity in a giant cell tumor of the tendon sheath is due to both

hemosiderin and fibrotic components

Axial T1WI and sagittal T2WI

MR images of the hand

demonstrate a GCT of the tendon sheath arising from

the flexor tendon of the index finger.

Giảm tín hiệu T2

Tầm quan trọng của vị trí

Other T2 hypointense lesions which

may be further characterized according

• Dupuytren disease Axial T2-weighted MR image demonstrates pigmented villonodular synovitis (PVNS)

arising from the tibiofibular joint

Giảm tín hiệu T2

U sợi đàn hồi

Axial T1 and STIR images demonstrate a low T1 and predominately low T2 signal intensity mass along the right

posterolateral chest wall MR appearance and location are most compatible with an elastofibroma

Giảm tín hiệu T2

Fibromatosis

Many lesions which demonstrate low T2 signal intensity remain

nonspecific Marked low T2 signal intensity in left gluteal

fibromatosis.

Axial T1WI and weighted MR images demonstrated

T2-homogeneous hypointense T1 and T2 signal in left gluteal

fibromatosis.

Tăng tín hiệu T2

Tổn thương dạng nang

Not all lesions that are homogeneously hyperintense on T2 are fluid-filled lesions (i.e cysts,

ganglia, and seromas) Myxomatous tumors, peripheral nerve sheath tumors, and even small synovial sarcomas can mimic cyst on T2WI

First step in characterization of these T2 hyperintense “cyst-like” lesions is administration of intravenous gadolinium contrast material.

Bắt thuốc bên trong(Tổn thương đặc)

• Myxoid Sarcoma

• Intramuscular

Myxoma Other:

Tăng tín hiệu T2 không bắt thuốc/bắt thuốc viền

Nang hạch

Coronal MR images demonstrate a ganglion near the right acromioclavicular joint T2-weighted

MR image shows a cyst-like area hyperintense lesion Contrast-enhanced T1-weighted MR image shows no significant enhancement

T2 FS

T1 + Gd

Tăng tín hiệu T2 có bắt thuốc bên trong

Tăng tín hiệu T2 có bắt thuốc bên trong

U nhầy

Coronal MR images demonstrate a low T1 and high T2 signal intensity mass in the

right subaxillary region Contrast-enhanced T1-weighted MR image shows

heterogeneous enhancement Myxomawas identified by pathology

Tăng tín hiệu T2 có bắt thuốc bên trong

liposarcoma dạng nhầy

Coronal MR images demonstrate mixed-intensity lesion within the region of the left shoulder The most

cephalad portion of the lesion is predominately fat with mild complexity Most caudal portion of lesion is

hypointense on T1WI and hyperintense on T2WI with enhancing mural nodularity Myxoid Liposarcoma was

identified on biopsy

Tóm tắt: Xác định đặc điểm tổn thương theo tín hiệu

Tổn thương chứa: Tổn thương:

Mỡ Lipoma(or variant), well-differentiated liposarcoma, hemangioma, heterotopic ossificationMethemoglobin Máu tụ

Chất giàu protein Nang hạch, abscess

Tổn thương chứa: Tổn thương:

Mô xơ Scar tissue, GCT of tendon sheath, plantar fibroma, elastofibroma, desmoid, fibrosarcoma,

lymphomaĐóng vôi đặc Cục tophi, đóng vôi loạn dưỡng

Hemosiderin U đại bào bao gân

thuốc viền/không bắt thuốc) Ganglion, seroma,abscess, epidermoid inclusion cyst

U đặc (bắt thuốc bên trong) Tổn thương dạng nhầy, PNST, synovial sarcoma

Tài liệu tham khảo

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• Chan WP Magnetic resonance imaging of soft-tissue tumors of the extremities: A practical approach

World Journal of Radiology 2013;5(12):455-459 doi:10.4329/wjr.v5.i12.455.

• Kransdorf MJ, Murphey MD Radiologic evaluation of soft-tissue masses: a current perspective Am J

Roentgenol 2000; 175:575–587.

• Kubiena H, Entner T, Schmidt M, Frey M Peripheral neural sheath tumors (PNST) what a radiologist

should know Eur J Radiol 2013;82(1):51–5 doi: 0.1016/j.ejrad.2011.04.037.

• Papp DF, Khanna AJ, McCarthy EF, Carrino JA, Farber AJ, Frassica FJ Magnetic resonance imaging of

soft-tissue tumors: determinate and indeterminate lesions J Bone Joint Surg Am 2007;89 Suppl

3:103–115.

• Wu JS, Hochman MG Soft-tissue tumors and tumorlike lesions: a systematic imaging approach

Radiology 2009;253:297–316