(Reproduced from October 98 issue)
This skill is based upon two essential components.
1 Observation, What you can see with the eye. Please don’t miss seeing anything.
§ First observe everything outside the chest, as once we are on real bussiness of lungs heart etc, We will miss whatever useful is visible outside the chest.
§ Read the name, age, date, time of exposure, R &L signs.
§ Look below diaphragm, shoulder joints & whatever is visible.
§ In the chest note all points especially apeces, &costopherinic angles
2 Analysis of observed points.
On quality of film. Please note following points.
*Positioning of patient
*Respiratory phase
* Degree of Exposure.
*Quality of Developing.
~Positioning of Patient.
Trachea should be in the middle & center should lie anterior to spinous processes of spine. Medial ends of clavicles should be equidistant from midline. For declaring increased transverse diameter of heart it is imperative that patient should be at 6 ft distance from the tube. If one hilum is prominent or a mass is suspected in one hilum, again make sure noting the position of clavicles & trachea does not tilt patient.
Both apeces & costopherinic angles should be crearly visible.
~Respiratory Phase
This is very important that film should be taken in full inspiratory phase. This can be determined easily on viewing film. Center of Diaphragm should be at 6th anterior rib. If it is at 4th or 5th rib then transverse diameter of heart can be artificialy increased.
~Degree of Exposure. Two criteria
1 Finger placed outside the chest behind blackest area should not be visible.
2 dorsal spine & disc spaces should be just visible behind heart shadow.
~ Quality of Developing
Depends upon, in addition to skill of the technitian,
Automatic precessors are best. The shine, usually missing from films is due to this. These processors produce that shine which we see in better films.
v All structures is bilateral except heart. Do compare one side with the other.
v 2 first note every thing outside the chest cavity. Soft tissue shadows, bone shadows, Look below diaphragms.
v 3 Next is ribs. Count anterior & posterior ribs. Observe for any abnormality at this time. Any fracure, lytic area, or expansion in the size.
v 4 then mediastinum look for the size, widening, shift, or presence of any mass. Note hila.
v 5 Heart. Note the right & left borders. Examine cardiopherinic angles. Note size. Maximum transverse diameter of heart should not be larger than 50 % of maximum internal transverse diameter of chest at any point.
Standard view is PA .All other views are secondary to this. For trauma conventiol teaching is AP view. But Dr Tarar does not see much advantage in it .PA is as good as AP.Lateral or Oblique views must always follow PA or AP views to eloborate some point futher.
Bronchovascular Markings
These comprise of 98 % vessels, mainly veins. Respiratory passages are not visible as these contain air. Normal shadows start from hila pass through proximal 1/3rd traverse to middle 1/3rd and just reach the border of distal third. Normaly markings are greatest in the medial part of lower zone. To say whether increased or not basically, in the opinion of Dr Tarar, it is an eyeball technique. With the experience your start saying this is increased or this is normal.
Increased Markings
This always means either Infection in respiratory passages or fluid overload. Infection may be acute or chronic. If radiologist reports increased bronchovascular markings but clinical situation is not supporting any thing it can be ignored and film should be taken as normal.
In cardiac failure cases so called reversal of pattern of markings occur. There is increase in markings in midzones due to fluid overload. Actually this is not reversal. This is only increase in midzones.
In chronic bronchitis markings are increased. In emphysema these are decreased in hyperinflated areas. In collapse of the lungs beyond the line-demarcating lung, these must be absent.
Different Terms used in reporting.
Shadowing, Patch, Patchy, infiltrations,
Opacity,
are nonspecific in the sense these do not mean specific disease. Rather these
are the terms used by different individuals in their own way to describe
geographical distribution of the abnormal findings. These define presence of
variation of whiteness or blackness in different grades. Different grades are
as followings.
1) Metal, 2) Bone 3) fluid, 4) soft tissue & 5)
air
in asending scale of blackness.
Initially collects in costopherinic angles. Rarely, on right side, in the fissure dividing middle & lower lobes. Small amounts, upto 100 mls, can be missed upon Xrays. Ultrasound can pick up these. Shadow should be homogeneous. Upper border should be ascending toward outside
Shadowing should be homogeneous. May dipict segmental or lobar divisions in lobar pneumonias.
Single most common cause is tuberculosis. Radiological findings are typical. Small fluid filled cysts distributed in increased markings are seen
Typical Tuberculosis Lesion.
In reply to: our question that is there any typical tuberculous lesion. He said certainly. When following features are present, he has no hesitation to declare lesion to be tuberculosis.
1 Specific areas like apeces.
2 Cavity formation
4 Calcification
5 Shifting due to fibrosis.
Uniform dense opacity filling costodiaphragmatic angle. Upper border is characteristic. It is concave, with raised lateral edge. Age, whole clinical picture & cardiac, renal & hepatic function should be kept in mind. As differential diagnosis is usually between fluid collection due to functional deficit, or infection, or malignancy.
Pulmonary Tuberculosis.
v Site. Due to orthostatic anaemia apices of upper & lower lobes are common areas. Usually it is upper lobe on one side & middle lobe on other side.
v Striate Opacities Increased striations between diseased area & hilum.
v Lymph nodes Usully not enlarged.
v Simultaneous healing & spread.
v Evidence of fibrosis, cavitation, calcification, are other important features.
v Small pleural and pericardial effusions may be there but usually missed by PA views.
v Dorsal Spine IV disc spaces may be seen reduced. Erosion of vertebral borders and abscess formation, presenting as paraspinal mass, may be visible on PA view.
v Primary complex typical lesions described previously i.e small shadowing with streaks towards hilum is usually not common. Rather increased course pattern of lung striations on one side, usually on Right side may be visible.