Recognizing Abnormal Calcifications and Their Causes

Chapter 16 Recognizing Abnormal Calcifications and Their Causes



image Soft tissue calcifications lend themselves to an intuitive approach that ties together a diverse group of diseases. While this chapter focuses primarily on abdominal calcifications, the same principles and approach apply to dystrophic calcifications found anywhere in the body.

image Dystrophic calcification is soft tissue calcification that occurs in tissue that is already abnormal. (Metastatic calcification, by contrast, is calcification in otherwise normal soft tissues due to disturbances in calcium/phosphorus metabolism.)

image On conventional radiographs, the nature of most calcifications can be determined by examining their pattern of calcification and their anatomic location.

image The same principles hold true for CT evaluation of calcifications except that the anatomic location is usually easier to determine on CT.


Patterns Of Calcification



image Calcifications tend to occur in one of four distinct patterns, depending on the type of structure that has calcified:
• Rimlike

• Linear or tracklike

• Lamellar (or laminar)

• Cloudlike, amorphous, or popcorn


Rimlike Calcification



image Rimlike calcification implies calcification that has occurred in the wall of a hollow viscus.

image Examples of structures that manifest rimlike calcifications:
• Cysts—calcification in any one of these is relatively uncommon.
• Renal cysts

• Splenic cysts

• Extraabdominal sites
• Mediastinal cysts, such as pericardial and bronchial cysts (Fig. 16-1).

• Popliteal cysts (Baker cysts)

• Aneurysms
• Aortic aneurysm. CT and US are used to identify and characterize abdominal aortic aneurysms. On conventional radiographs, such aneurysms are most easily recognized on a lateral radiograph of the lumbar spine. The abdominal aorta should normally measure <3 cm in diameter (Fig. 16-2).

• Splenic artery or renal artery aneurysms—usually secondary to atherosclerosis.

• Extraabdominal sites
• Femoral artery aneurysms

• Cerebral aneurysms

• Saccular organs, such as the gallbladder or urinary bladder
• Porcelain gallbladder—an uncommon entity (named after the gross appearance of the gallbladder, which resembles porcelain) that occurs with chronic inflammation of and stasis in the gallbladder and is associated with gallstones and an increased incidence of carcinoma of the gallbladder (Fig. 16-3).

• Urinary bladder—calcification of the wall is an uncommon occurrence in diseases such as schistosomiasis, bladder cancer, and tuberculosis.

image Table 16-1 highlights key facts about rimlike calcifications.

image

Figure 16-1 Calcified pericardial cyst.


There is a rimlike calcification (solid white arrows) that identifies the structure containing the calcification as cystic or saccular. The calcification is in the right cardiophrenic angle, an ideal location for pericardial cysts. Pericardial cysts are usually asymptomatic and discovered when a chest radiograph is obtained for another reason.


image

Figure 16-2 Calcified aortic aneurysm.


Calcification in the wall of the abdominal aorta is a common finding in atherosclerosis, especially in those with diabetes mellitus. In this patient, the aorta is enlarged and demonstrates a rimlike calcification (solid white arrows). The opposing wall is also calcified, but overlaps the spine. An aneurysm is present when the diameter of the abdominal aorta exceeds its normal diameter by more than 50%.


image

Figure 16-3 Calcified gallbladder wall.


The rimlike calcification (solid white arrow) identifies this as occurring in the wall of a cyst or saccular organ. The calcification is in the right upper quadrant, the location of the gallbladder. This is a porcelain gallbladder, an uncommon entity (named after the gross appearance of the gallbladder which resembles porcelain) that occurs with chronic inflammation and stasis and is associated with gallstones and an increased incidence of carcinoma of the gallbladder.


TABLE 16-1 RIMLIKE CALCIFICATIONS


















Organ of Origin Remarks
Renal cyst Thick and irregular calcifications, though uncommon, may indicate the presence of renal cell carcinoma.
Splenic cysts May be a manifestation of hydatid cyst, old trauma, or prior infection.
Aortic aneurysms Occurs more often in diabetics with advanced atherosclerosis.
Gallbladder Associated with chronic stasis; called porcelain gallbladder for its gross appearance; higher incidence of carcinoma of the gallbladder.


Linear Or Tracklike Calcification



image Linear or tracklike calcifications imply calcification that has occurred in the walls of tubular structures (Fig. 16-4).

image Examples include calcifications in the walls of:
• Arteries
• Common in atherosclerosis and seen anywhere in the body.

• Walls of veins do not calcify. In veins, long, linear thrombi or small, focal thrombi (the latter called phleboliths) may calcify (see Fig. 13-18).

• Tubular structures
• Fallopian tubes and vas deferens—seen more often in diabetics (Fig. 16-5).

• Ureter—uncommon finding seen in schistosomiasis and even more rarely in tuberculosis.

image Table 16-2 highlights key facts about linear or tracklike calcifications

image

Figure 16-4 Calcified arterial wall.


There is linear or tracklike calcification present (solid black arrows), which implies calcification that has occurred in the walls of tubular structures. In the leg, this is calcification in the femoral artery. Such wall calcification occurs in arteries, not veins, and is usually secondary to atherosclerosis, frequently associated with diabetes, or in patients with chronic renal disease. This patient obviously suffered one of the complications of diabetes and has had an above-the-knee amputation (solid white arrow) of a formerly gangrenous leg.


image

Figure 16-5 Calcification of the vas deferens.

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Mar 2, 2016 | Posted by in GENERAL RADIOLOGY | Comments Off on Recognizing Abnormal Calcifications and Their Causes

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