8 Techniques in Thoracic Imaging Dr. Muhammad Bin Zulfiqar Grainger and Allison We will discuss the Imaging techniques in Thoracic Imaging

1. 8
Techniques in Thoracic Imaging
DR MUHAMMAD BIN ZULFIQAR
PGR III FCPS Services institute of Medical
Sciences/ Services Hospital Lahore
GRAINGER & ALLISON’S DIAGNOSTIC RADIOLOGY

2. • FIGURE 8-1 ■ Series of dual-energy subtraction chest
radiographs in a healthy man. A right apical opacity is
seen on a conventional posteroanterior radiograph (A),
but a soft-tissue nodule in the left apex only becomes
conspicuous on a bone-subtracted image (B).
Additionally, a soft-tissue subtracted image (C) reveals
that the right apical opacity is actually calcification of
the first costochondral junction. (With permission from
McAdams HP, Samei E, Dobbins J III, et al 2006 Recent
advances in chest radiography. Radiology 241(3): 663–
683.)

3. • FIGURE 8-2 ■ Suspected pulmonary metastases in a man with
poorly differentiated adenoid cystic carcinoma. On a 1-mm-thin
section image (A), a subpleural nodule (black arrow) is easily seen,
but a central nodule (white arrow) can be mistaken for a pulmonary
vessel. Scrolling through 10-mm-thick maximum intensity
projection (MIP) images (B) can show the central nodule as distinct
from the adjacent vessel (white arrow), and make the subpleural
nodule more conspicuous (black arrow).

4. • FIGURE 8-3 ■ Geometry of a dual-source CT
system. The two tubes are positioned at 90°
to each other, diametrically opposite their
detector arrays.

5. • FIGURE 8-4 ■ Geometry and dose profile for spiral, 4-, 16-
and 64-slice CT. In spiral CT, the whole dose within the
umbral region (U) contributes to image reconstruction with
no wastage. In 4-slice CT, wastage occurs within the
penumbral regions (P). The relative contribution of the
penumbral region decreases with an increasing number of
simultaneously acquired sections. The effect of this
wastage is minimised in 64-slice CT.

6. • FIGURE 8-5 ■ Screenshot from volumetric
analysis of a low-dose CT study in a lung cancer
screening trial. The CT parameters were based
on the patient’s body weight, with the effective
mAs kept at 22 mAs and a tube potential of 120
kVp.

7. • FIGURE 8-5 ■ Screenshot from volumetric
analysis of a low-dose CT study in a lung
cancer screening trial. The CT parameters
were based on the patient’s body weight, with
the effective mAs kept at 22 mAs and a tube
potential of 120 kVp.

8. • FIGURE 8-6 ■ (A)
Unenhanced and (B)
intravenously enhanced
volumetric 1-mm section
HRCT images in a patient
with biopsyproven non-
specific interstitial
pneumonia, taken one
week apart. Generally,
increased ground-glass
opacity is seen in both
lungs, but it is difficult to
determine whether this
represents new parenchymal
opacification, or whether it
is purely the consequence of
contrast enhancement.

9. • FIGURE 8-7 ■ HRCT for
suspected asbestosis. (A) HRCT
image in the supine position
demonstrates fine reticulation
and increased subpleural
density (arrows). (B) These
changes (arrows) persist on the
prone image and may
represent early asbestosis in
this patient who had an
appropriate asbestos exposure.

10. • FIGURE 8-8 ■ Mosaic
attenuation in a
patient with
bronchiectasis in the
lower lobes (not
shown). HRCT image
taken in inspiration
(A) shows subtle
mosaicism,
emphasised in the
section acquired at
end-expiration (B),
indicating small
airways disease.

11. • FIGURE 8-9 ■ Ultrasound evaluation of
empyema. Multiple septations (arrows) are
present within the anechoic pleural collection.

12. • FIGURE 8-10 ■ Endobronchial ultrasound-
transbronchial aspiration (EBUS-TBNA) of a
subcarinal node in a patient with mediastinal
lymphadenopathy. The needle is visualised as a
linear focus of high echoreflectivity (arrow).
(Courtesy of Dr Pallav Shah, Royal Brompton
Hospital.)

13. • FIGURE 8-11 ■ Anterior
mediastinal mass in a
54-year-old woman
incidentally discovered
during MRI of the
thoracolumbar spine. A
well-circumscribed ovoid
anterior mediastinal
lesion is present (arrows)
that is hypointense on
T1-weighted (A) and
markedly hyperintense
on T2-weighted (B)
sagittal MR images
relative to muscle. The
appearances are
consistent with a thymic
cyst.

14. • FIGURE 8-12 ■ Coronal
hyperpolarised 3He MR
images of 24-yearold (A) and
17-year-old (B) patients with
cystic fibrosis, with FEV1 of
109 and 52%, respectively.
Both patients demonstrate
multiple ventilation defects,
but the patient in (B) with
the poorer FEV1 shows
defects which are both larger
and more widespread. (With
permission from Ohno Y,
Koyama H, Yoshikawa T, et al
2011 Pulmonary magnetic
resonance imaging for airway
diseases. J Thorac Imaging
26(4): 301–316.)