Diagnostic ultrasound ( PDFDrive )

CHAPTER 17 Ultrasound-Guided Biopsy of Chest, Abdomen, and Pelvis 607
A
B
C
FIG. 17.8 Arteriovenous (AV) Fistula After Renal Transplant
Biopsy. (A) Longitudinal ultrasound image of renal
transplant demonstrates an 18-gauge needle in the lower pole.
(B) Color Doppler ultrasound 3 weeks later demonstrates focal
communication between a renal artery and vein (arrow), indicating
AV istula. (C) Spectral Doppler image demonstrates the
high-velocity and low-resistance waveform of AV istula. Most
AV istulas are of no clinical signiicance and spontaneously
thrombose.
require biopsy because these should represent benign adrenal
myelolipomas and cysts, respectively. CT or MRI can be performed
to conirm this before considering biopsy.
Although benign adenomas can be larger than 3 cm, the
likelihood of silent adrenal carcinoma increases signiicantly if
an incidentally discovered adrenal mass is larger than 4 cm. 86
In this setting, surgical excision is recommended because biopsy
will yield insuicient tissue to diferentiate a benign adenoma
from adrenocortical carcinoma.
Radiologists performing adrenal biopsies should be familiar
with the management of a hypertensive crisis ater inadvertent
biopsy of a pheochromocytoma. 87 Although adrenal pheochromocytomas
have been safely biopsied without premedication, 84
if the clinical history suggests pheochromocytoma, further
laboratory tests, not biopsy, should establish the diagnosis. If
biopsy is necessary, consultation with an endocrine specialist
and pretreatment with alpha-adrenergic blockers and metyrosine
should be considered. 88
Spleen
he spleen is the abdominal organ that undergoes biopsy least
oten. First, isolated metastases to the spleen are exceptionally
rare. In most cases, when the splenic tumor is visualized, there
is concomitant disease in other abdominal organs, such as the
liver or lymph nodes, in which a biopsy can be performed. Second,
the spleen is a highly vascular organ, and the risk of needle
biopsy would seem to be high. he reported rate of signiicant
hemorrhage from needle biopsy varies from no hemorrhage up
to 8%. 89-98 In some cases, splenectomy is required. 91,99 Pneumothorax
may also occur as a complication ater spleen biopsy. 97
At this time, the main clinical reason for performing percutaneous
biopsy of the spleen is to diferentiate recurrent lymphoma,
metastasis, and infection in a patient who has a new splenic
lesion but no disease elsewhere in the abdomen (Fig. 17.10). In
the immunocompromised patient, diferentiation between
malignancy and fungal infection can be critical in patient
management. Percutaneous biopsy can yield a speciic diagnosis
in approximately 90% of patients. 90,91,100
Lung
Percutaneous biopsy of the lung is typically performed with CT
guidance. However, ultrasound has proved to be efective in the
biopsy of masses that abut the chest wall, without the imaging
interference of aerated lung parenchyma 101,102 (Fig. 17.11). Such
lesions include pulmonary, pleural, and mediastinal masses.
Notable advantages of ultrasound in the lung include (1) real-time
guidance during patient respiration, (2) ability to biopsy eiciently
in the of-axial plane, (3) ability to biopsy lesions in patients