الفهرس 
Gross anatomy of the lungOnly 14 pages are availabe for public view
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Abstract
Postprocedural cross-sectional imaging is a must to assess the
response to treatment. Computed tomography (CT), positron emission
tomography (PET), and dual-modality imaging with combined PET and
CT (PET/CT) are primarily used for this purpose. It also allows detection
of procedure-related complications, metachronous tumors, and metastatic
disease.
An understanding of the anticipated and unexpected imaging features
of the RFA zone is essential for accurate assessment of the response to
treatment. Because a patient with recurrence may potentially undergo
repeated treatment if the recurrence is detected early, the recognition of
early signs of incomplete therapy or recurrence is also critical.
Post-RFA follow-up was divided into three phases: early
(immediately after to 1 week after RFA), intermediate (>1 week to 2
months), and late (>2 months). CT and PET imaging features suggestive of
residual or recurrent disease include (a) increasing contrast material uptake
in the ablation zone more than the preablation tumor (>180 seconds on
dynamic images), nodular enhancement measuring more than 10 mm, any
central enhancement greater than 15 HU, and enhancement greater than
baseline any time after ablation; (b) growth of the RFA zone after 3
months (compared with baseline) and definitely after 6 months, peripheral
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nodular growth and change from ground-glass opacity to solid opacity,
regional or distant lymph node enlarge¬ment, and new intrathoracic or
extrathoracic disease; and (c) increased met¬abolic activity beyond 2
months, residual activity centrally or at the ablated tumor, and
development of nodular activity.
Reliable imaging surveillance after thermal ablation is essential and
remains a mainstay for its continued success. A firm understanding of the
expected and unexpected imaging features of the ablation zone is critical
for accurate assessment of treatment response and early identification of
incomplete ablation, and locoregional and/or distant progression of
disease. Non enhanced and contrast-enhanced CT, PET, and PET/CT
should be used in conjunction as routine follow-up or as problem-solving
modalities, and biopsy should be entertained whenever imaging findings
are equivocal. Even with 100% local control, an already predetermined
number of treated individuals will have microscopic disease beyond their
ablated tumor that is below the detection of currently available imaging
techniques. This, further exacerbated by high-risk patient populations in
which pathologic staging is unavailable, should drive diligent and rigorous
patient follow-up.