MRI Chest

Thoracic Organs

Both lungs are normally aerated and are applied to the chest wall on all sides. The pleurae show normal homogeneous signal intensity, and there are no fluid collections.

The pulmonary structure is normal and presents normal vascular markings. There are no intrapulmonary nodules or patchy densities. The mediastinum is centered and of normal width. There is no evidence of masses in the anterior, central, or posterior compartment. The hilar region on each side is unremarkable, and the main bronchi appear normal. There is no lymphadenopathy and there are no perihilar masses.

The heart is orthotopic and has a normal configuration. The cardiac chambers are of normal size.

Major intrathoracic vessels are unremarkable, and imaged portions of the supra-aortic vessels appear normal.

The thoracic skeleton and thoracic soft tissues show no abnormalities. Interpretation

The thoracic organs appear normal.

Checklist

Lungs • Anatomy (paired and symmetrical)

• Fully apposed to the chest wall

• No pleural thickening

• No fluid collection (patchy or circumscribed)

• Normal aeration

• Normal low signal of the lung parenchyma

• Normal pulmonary structure

• Vascular markings diminish from center to periphery

• No pulmonary nodules

• No larger densities (e.g., plaques or infiltrates) Mediastinum • Configuration

Vessels

Diaphragm

Thoracic skeleton • (ribs, clavicle, • sternum, scapula) •

Thoracic soft tissues

— No masses in the anterior, central, or posterior compartment

Hilar region:

— No lymphadenopathy Main bronchi:

— Position (centered slightly left of midline)

— Configuration

— Size of cardiac chambers (see below)

— Normal myocardial thickness (see below) Intrathoracic vessels (ascending aorta, aortic arch, descending aorta, vena cava):

Supra-aortic vessels (subclavian artery, brachio-cephalic trunk, left common carotid artery):

Shape (bell-shaped, no contour abnormalities, costophrenic angle is sharp and clear) Position (at approximately the level of the 10th-11th posterior rib)

Width (no circumscribed widening, no defect) Position

Structure and signal characteristics Contours and symmetry No bony expansion or destruction Thoracic spine:

— Position and shape of thoracic vertebrae

— Signal characteristics of thoracic vertebrae Normal

Symmetrical

Important Data

1

Angle of tracheal bifurcation:

• Approximately 55-65°

2

Diameter of main bronchi:

a Right approx. 15 mm

b Left approx. 13 mm

3

Diameter of aorta:

• < 4 cm

a Ascending aorta:

a1 At level of pulmonary trunk bifurcation: 3.2 cm ± 0.5 cm

a2 At level of aortic root: 3.7 cm ± 0.3 cm

b Aortic arch: 1.5 cm ± 1.2 cm

c Descending aorta: 2.5 cm ± 0.4 cm

Ratio of ascending to descending aortic diameters = 1.5:1

4

Diameter of superior vena cava:

a At level of aortic arch: 1.4 cm ± 0.4 cm

b At level of pulmonary trunk bifurcation: 2 cm ± 0.4 cm

5

Diameter of pulmonary arteries:

a Pulmonary trunk: 2.4 cm ± 0.2 cm

b Proximal right pulmonary artery: 1.9 cm ± 0.3 cm

c Left pulmonary artery: 2.1 cm ± 0.4 cm

6

Mediastinum:

• Thymus 1-2 cm in transverse diameter

Heart:

Dimensions of cardiac chambers:

7

Right atrium:

• Maximum transverse diameter: 4.4 cm

a At level of aortic root: 1.9 cm ± 0.8 cm

b At level of mitral valve: 3.2 cm ± 1.2 cm

c At center of ventricles: 2.8 cm ± 0.4 cm

8

Left atrium:

a Maximum anteroposterior diameter: 4-5 cm

a1 At level of aortic root: 2.4 cm ± 4.5 cm

a2 At level of mitral valve: 2.9 cm ± 4.9 cm

b Maximum transverse diameter: 9 cm

b1 At level of aortic root: 5.5 cm ± 8.4 cm

b2 At level of mitral valve: 4.9 cm ± 9.1 cm

9

Angle between midsagittal plane and septum = 38° (in-

creases in response to pressure loading or volume loading of

the ventricles)

10

Thickness of ventricular septum:

• Approximately 5-10 mm

Coronal image

11 Thickness of pericardium:

12 Thickness of myocardium:

Axial image at level of pulmonary trunk bifurcation
Axial image at level of aortic root
Axial image at level of mitral valve
Axial image through center of ventricles

Breast

The anatomy of the glandular breast tissue is symmetrical and normal for age. The breast parenchyma is uniformly subdivided by fatty tissue. Unenhanced MR images show no lesions that are hypointense or hyper-intense to the breast parenchyma or fat.

Following contrast administration, a significant, abnormal rise in signal intensity is not observed in any segment of the breast. The skin and subcutaneous tissues show no abnormalities.

Interpretation

The breasts appear normal.

Checklist

Breast parenchyma

Noncontrast images

Postcontrast images

Skin and subcutaneous tissues

Axilla (unless obscured by motion artifacts)

Size

Symmetry

Extent of breast parenchyma in relation to fat (note physiological involution of the parenchyma with aging)

Symmetrical development of glandular breast tissue

Uniform subdivision by fat

No lesions that are hypointense or hyperintense to the breast parenchyma or fat (cysts, solid tumors, stellate densities)

No significant abnormal enhancement (more than about 70% of initial signal intensity in the early phase after contrast administration)

No abnormal enhancing structures on delayed images

Early, intense enhancement of the nipple area (confirms proper injection technique) Thickness No retraction

No circumscribed expansion No lymphadenopathy

Lungs (unless • obscured by • motion artifacts) •

Heart (unless obscured by motion artifacts)

Complete aeration No pulmonary nodules

Bony structures (ribs and sternum, unless obscured by motion artifacts):

— No voids or expansion

— Retrosternal structures (lymph nodes along internal thoracic artery) appear grossly normal

Shape Size

Position

Enhancement characteristics

Axial image through the center of the breasts following contrast administration (Gd-DTPA: gadolinium diethylenetriaminepentaacetate)

Subtraction image of the breasts
3-D MIP (Maximum Intensity Projection) rendering of subtraction images

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