This document discusses various imaging and diagnostic techniques used in surgery, including x-rays, tomography, ultrasound, CT scans, MRI, isotopes scans, endoscopy, and biopsies. Plain x-rays can detect calcified tissues like stones. Tomography focuses on deep tissues. Contrast x-rays and intravenous pyelograms outline organs and detect kidney tumors. Angiography detects artery blockages. Ultrasound is noninvasive and detects masses, organs, and stones. CT scans create slices of the body. MRI uses magnetic fields to produce images especially of the brain and spinal cord. Isotope scans use radioactive tracers to image organs. Endoscopy examines organs through natural openings. Biopsies obtain tissue samples

1. INVESTIGATIONS IN
SURGERY

2. • Conventional radiography.
– Plain X – ray:
• This is useful as x ray penetrate the various
tissues to different depth.
• On a plain radiograph gas and fat absorbs few
xray (Radiolucent) and appear as dark area.
• Bones and other calcified tissues absorbs most of
the xray and so not penetrated by xray and appear
as white areas.
• So abnormal calcified tissue like urinary stones,
gall stones are visible in plain xray.

3. – Tomography:
• In this x ray tube and film are moved in opposite direction
focusing on a particular point, which is clearly seen in the
film. Useful to see deep seated masses.
– Contrast X rays:
• when contrast material is given orally it fills up the organ
concerned and shows the outline (shape) of the organ. Eg:
cancer of stomach ( filling defect)
– Direct contrast studies:
• Eg. Intravenous pyelogram(IVP)
• Contrast is given intravenously and it is excreted by the
kidneys in the urine. In this process kidneys get visualized
and any abnormality in the kidney can be made out. Eg.
Tumours of kidneys.

4. – Intra arterial injection of contrast:
• Eg. Angiography
• Water soluble contrast medium which is radioopaque is
injected into an artery and xrays taken rapidly to show
obstruction due to thrombosis , atheroma, embolism etc.
• Site of obstruction can be clearly made out.
• Eg. Coronary angiography.
• It will be useful to do Bye – pass surgeries where there is a
block in an artery.
• Arteriogram will also detect localized dilatation of an artery –
aneurysm.

5. • Ultra sound:
– It is a non-invasive, safe and painless procedure.
– An ultrasound probe containing ‘ transducer’ is
applied on the skin over the area and moved in
different directions .
– The transducer sends microsounds and listens for
deflected ultrasound ‘echoes’ and records them, and
the image is displayed on the television screen.
– The length and breadth of the organs can be
determined.
– Bones and stones (calcified) produce complete
deflection of ultrasound and can be detected.

6. – Ultrasound uses:
• Very useful in obstetrics as it shows size of uterus,
and position of faetus and congenital abnormalities
of foetus.
• Solid and cystic lesion
• Assessing masses in abdomen and pelvis
• Detecting stones in gall bladder and kidneys.

7. – Ultrasound limiting factors:
• Bones completely deflect ultrasound and obscures
tissues beyond them
• Fat scatters ultrasound waves and obscures
• Gas in bowels interfere with ultrasound.

8. • Computerized tomography ( CTscan):
– This is x raying a series of thin transverse
‘slices’ of patients skull or body.
– Pathological anatomy can be studied in detail
, very useful in brain injury. Head scan will
show clearly ‘clot’ in brain injury or tumour
and help timely intervention.
– Similarly total body scan can show internal
organs of abdomen.

9. • Magnetic Resonance imaging (MRI) or Nuclear
Magnetic Resonance (NMR):
– Newly developed technique with rapidly expanding
diagnostic applications.
– MRI involves applying powerful magnetic field to
body, which causes all protons of hydrogen nuclei to
get aligned. They are then excited by radiowaves
which caused them to resonate and produce radio
signals, which are recorded electronically and images
are produced.

10. – Main application of MRI is for brain and spinal
cord.
– Atheroma can be demonstrated
– They have very good use in cardiac and
vascular surgeries.

11. • Isotope scan:
– Suitable tracer agents combine a substance
physiologically taken up in target tissue and
radio active label (99m technetium) is
concentrated in the tissues.
– Eg: I 131 . This isotope is used to evaluate
thyroid function.
– Technetium 99m scan can be used for liver
and spleen scan and bone scan.

12. • Endoscopy:
– It is the method of looking into organs of body
through a flexible instrument(fibre optic) via
natural orifices (nose or mouth) or through a
artificial opening(peritoneoscopy).
– Gastroscopy: to see mucosa of a stomach
and duodenum (eg. Peptic ulcer)
– Others: colonoscopy , cystoscopy etc.

13. • Biopsy:
– If major surgery is contemplated for a malignant
lesion, an accurate tissue diagnosis must be made.
– This can be made only possible by biopsy.
– Excision biopsy:
• The entire tissue is removed and sent for histopathological
examination.
• Eg. Lymph node biopsy – enlarged lymph node is completely
removed.
– Needle biopsy:
• Large biopsy needle ( 14 or 18 gauge) is used to take a bit of
tissue for biopsy eg. Liver biopsy.

14. – Fine needle aspiration biopsy cytology:
• FNAC
• A fine needle (22 gauge) is passed through a
suspicious lesion and fine fragments of tissues
aspirated and sent for cytological examination.
• Eg.solitary nodular goitre.