Chest

Question 1

1. Which of the following are correct regarding Adult respiratory distress syndrome (ARDS):

(a) CXR is usually normal in the first 24 h.

(b) The lung is uniformly abnormal on CT.

(c) Has 50% mortality.

(d) The most common CT abnormality in survivors in a reticular pattern.

(e) Bronchial dilatation is seen frequently on CT.

Answer 1

Answers:

(a) Correct

(b) Not correct

(c) Correct

(d) Correct

(e) Correct

Explanation:

Lung involvement is heterogeneous with a gradient density. Dependent lung is more densely opacified than nondependent lung.

Question 2

7. Which of the following are correct regarding pulmonary disease in AIDS patients: (T/F)

(a) Lymphocytic interstitial pneumonia usually progresses to lymphoma in children.

(b) Bilateral perihilar infiltrates on CXR are diagnostic of Pneumocystis Carinii pneumonia.

(c) The presence of Cytomegalovirus in bronchoalveolar lavage fluid indicates active infection.

(d) Lymphadenopathy is seen in <5% of cases of Kaposi’s sarcoma.

(e) Thick-walled cavities are a common HRCT finding of invasive pulmonary aspergillosis.

Answer 2

Answers:

(a) Not correct.

(b) Not correct.

(c) Not correct.

(d) Not correct.

(e) Correct.

Explanation:

Bilateral perihilar infiltrates are a non-specific findings seen in other opportunistic infections as well like CMV and Kaposi’s sarcoma. On HRCT, PCP is most commonly seen as bilateral, symmetric, patchy or confluent ground glass opacity. Less common findings on CXR and HRCT include focal areas of consolidation, mass lesions, multiple lung nodules, pleural fluid, pneumothorax, cavitation, lymphadenopathy and occasional nodal calcification.

CMV is the most common viral pathogen to cause morbidity and mortality in patients with AIDS. The HRCT findings are heterogeneous and include bilateral ground glass opacities, multiple nodules or mass like areas of consolidations and patchy bilateral consolidation.

Pulmonary KS occurs in 18% to 50% of patients with known cutaneous KS and can affect the lung parenchyma, pleural or tracheobronchial tree. Bilateral perihilar pulmonary infiltrates is the most common finding. Other common findings include intralobular septal thickening, lymphadenopathy and pleural effusion.

Lymphocytic interstitial pneumonia is a lymphoproliferative disorder seen with increased frequency in mainly children affected by AIDS. It is mostly benign and regresses spontaneously or with treatment.

Question 3

@# 5. Which of the following are correct about pulmonary sarcoidosis: (T/F)

(a) Normal CXR excludes the diagnosis.

(b) The large airways are involved in 4-5% of cases.

(c) Subcarinal lymph nodes are characteristically spared.

(d) Fibrosis occurs predominantly in the lower zones.

(e) Pleural effusion is common CXR.

Answer 3

Answers:

(a) Not correct.

(b) Correct

(c) Not correct

(d) Not correct

(e) Not correct

Explanation:

Between 5% to 15% of patients have a normal CXR when first examined.

Pleural effusion is a rare finding (2%).

All mediastinal lymphnodes can be affected in sarcoidosis.

On CT 50% of cases show enlarged subcarinal lymphnodes.

Middle and upper zone fibrosis is characteristic

Question 4

10. Which of the following are correct regarding Langerhans’ cell histiocytosis. (T/F)

(a) Primarily affects cigarette smokers.

(b) Predominantly affects the lung bases.

(c) Most patients are asymptomatic.

(d) Nodular lesions frequently cavitate.

(e) Lung volumes are reduced.

Answer 4

Answers:

(a) Correct

(b) Not correct

(c) Not correct

(d) Correct

(e) Not correct

Explanation:

LCH mostly involves upper and mid zones with relative sparing of lung bases and characteristic appearance of bilateral nodular and reticulo-nodular areas. Most patients are symptomatic with non-productive cough and/or dyspnoea. Lung volumes are characteristically normal or increased.

Question 5

16. When a mass-like lesion is seen on CT, which of the following findings support the diagnosis of rounded atelectasis. (T/F)

(a) An anteromedial location of the mass.

(b) An acute angle with the pleural margins.

(c) Localized crowding of the pulmonary vasculature.

(d) Adjacent pleural thickening.

(e) Absence of enhancement following intravenous contrast.

Answer 5

Answers:

(a) Not correct

(b) Correct

(c) Correct

(d) Correct

(e) Not correct

Explanation:

Round atelectasis is usually seen in posterior or basal region of lower lobes and appears as a well-defined oval or round mass in subpleural location. On Ct the mass shows uniform post intravenous contrast enhancement.

Question 6

15. Which of the following are true regarding silicosis? (T/F)

(a) It predominantly affects the lower lobes in acute silicoproteinosis.

(b) Emphysema is associated with the development of progressive massive fibrosis.

(c) It mimics sarcoidosis on high resolution computed tomography (HRCT).

(d) It is a more frequent cause of nodal egg-shell calcification on radiograph than coal miner’s pneumoconiosis.

(e) Impairment of the lung function test correlates best with the profusion of nodules.

Answer 6

Answers:

(a) Not correct

(b) Correct

(c) Correct

(d) Correct

(e) Not correct

Explanation:

Acute silicoproteinosis has mid and upper zone predominance occurs from intense exposure to silica dust resulting in alveolar exudates. Impairment of the lung function test correlates best with the degree of emphysematous change. Nodular perfusion is a weaker independent correlate.

Question 7

17. Which of the following are true regarding usual interstitial pneumonitis (UIP)? (T/F)

(a) It is more common in females than males.

(b) It occurs most frequently in the sixth decade of life.

(c) It is the most common cause of cryptogenic fibrosing alveolitis.

(d) Areas of ground glass attenuation on HRCT in the absence of parenchymal distortion indicate reversibility.

(e) A confident diagnosis cannot be made on HRCT without lung biopsy.

Answer 7

Answers:

(a) Not correct

(b) Correct

(c) Correct

(d) Correct

(e) Not correct

Explanation:

UIP has no gender predilection.

On HRCT temporal heterogeneity is characteristic of UIP and it refers to different areas of lung demonstrating different stages of inflammation and fibrosis at the same time. This helps to make confident diagnosis in majority of the cases

Question 8

33. Which of the following are correct regarding Goodpasture’s syndrome: (T/F)

(a) Hilar lymph nodes may be enlarged.

(b) Changes are commonly unilateral.

(c) Prognosis is good.

(d) Acute presentation is with air-space consolidation typically at the lung apices.

(e) Signs of renal failure precede pulmonary complaints.

Answer 8

Answers:

(a) Correct

(b) Not correct

(c) Not correct

(d) Not correct

(e) Not correct

Explanation:

Goodpasture’s syndrome is bilateral with poor prognosis and death usually within 3 yrs of diagnosis. Pulmonary involvement is before renal involvement with relative sparing of lung apices.

Question 9

35. Which of the following are correct regarding lymphangioleiomyomatosis (LAM): (T/F)

(a) Pulmonary abnormalities are similar to those seen in tuberous sclerosis.

(b) It is found exclusively n females.

(c) Cysts commonly have a bizarre outline.

(d) Cysts show sparing of the apices.

(e) There is an association with chylothorax.

Answer 9

Answers:

(a) Correct

(b) Correct

(c) Not correct

(d) Not correct

(e) Correct

Explanations:

In LAM cysts are usually uniform and round with uniform distribution. Cysts in LCH have bizarre irregular outlinesand show apical sparing.

Question 10

35. Which of the following are correct regarding lymphangioleiomyomatosis (LAM): (T/F)

(a) Pulmonary abnormalities are similar to those seen in tuberous sclerosis.

(b) It is found exclusively n females.

(c) Cysts commonly have a bizarre outline.

(d) Cysts show sparing of the apices.

(e) There is an association with chylothorax.

Answer 10

Answers:

(a) Correct

(b) Correct

(c) Not correct

(d) Not correct

(e) Correct

Explanations:

In LAM cysts are usually uniform and round with uniform distribution. Cysts in LCH have bizarre irregular outlinesand show apical sparing.

Question 11

37. Causes of eggshell calcification of lymph nodes include: (T/F)

(a) Rheumatoid arthritis.

(b) Silicosis.

(c) Scleroderma.

(d) Histoplasmosis.

(e) Amyloidosis.

Answer 11

Answers:

(a) Not correct

(b) Correct

(c) Correct

(d) Correct

(e) Correct

Explanation:

Rheumatoid arthritis rarely shows lymphnodal calcification.

Question 12

40. Features of pulmonary asbestosis include: (T/F)

(a) Increased severity in sub-pleural zones.

(b) Hilar adenopathy.

(c) Upper lobe massive fibrosis.

(d) Thickened interlobular septa on HRCT.

(e) Increased incidence of bronchio-alveolar cell carcinoma.

Answer 12

Answers:

(a) Correct

(b) Not correct

(c) Not correct

(d) Correct

(e) Correct

Explanation:

Asbestosis shows lower lobe fibrosis with no hilar lymphadenopathy.

Question 13

8. Which of the following are correct regarding HRCT features of pulmonary alveolar proteinosis (PAP): (T/F)

(a) Usually shows a lower zone distribution.

(b) Pleural effusion is common at presentation.

(c) Lymphadenopathy is a common feature.

(d) Regions of emphysema are commonly observed.

(e) Crazy paving pattern is a specific feature

Answer 13

Answers:

(a) Correct

(b) Not correct

(c) Not correct

(d) Not correct

(e) Not correct

Explanation:

Pleural effusion is rare in untreated PAP.

Lymphadenopathy is uncommon.

Crazy paving pattern though suggestive of PAP, is also seen in ARDS, acute interstitial pneumonia and drug induced pneumonias

Question 14

9. Which of the following are correct regarding extrinsic allergic alveolitis (EAA): (T/F)

(a) A normal CXR excludes the diagnosis.

(b) Smoking is a risk factor.

(c) The upper zones are typically involved in acute EAA.

(d) Ground-glass opacity is a characteristic HRCT finding.

(e) Bronchiectasis is seen on HRCT in chronic EAA

Answer 14

Answers:

(a) Not correct

(b) Not correct

(c) Not correct

(d) Correct

(e) Correct

Explanation:

CXRs are generally normal in patients with mild symptoms and in some cases with severe symptoms.

Smokers are protected from EAA also called hypersensitivity pneumonitis.

The most common forms are farmer’s lung and bird fancier’s lung.

Typically mid to lower zones are affected with sparing of costophrenic angles.

Presentation is like pulmonary oedema with bilateral areas of increased opacity that may be heterogeneous or homogeneous.

Question 15

18. Which of the following are true regarding cryptogenic organising pneumonia (COP)? (T/F)

(a) The disease is rarely symptomatic.

(b) An obstructive pattern of lung function impairment is typical.

(c) Pleural effusions are common.

(d) Radiographic clearing occurs following steroid treatment.

(e) Bilateral basal peripheral consolidation is a common radiographic finding

Answer 15

Answers:

(a) Not correct

(b) Correct

(c) Not correct

(d) Correct

(e) Correct

Explanation:

50% of the patients are symptomatic presenting with fever, cough, breathlessness and malaise with peak incidence in5th and 6th decades of life. COP is also known as BOOP (bronchiolitis obliterans organizing pneumonia) or bronchiolitis obliterans with intramural polyps.

Pleural effusion is uncommon (5% cases

Question 16

4. Regarding diagnosis of pulmonary embolism (PE): (T/F)

(a) A negative D-dimer test reliably excludes PE in patients with low clinical probability.

(b) A positive D-dimer test is highly specific for PE.

(c) A normal isotope lung scan reliably excludes PE.

(d) Patients with a good quality negative CTPA do not require further investigation or treatment for PE.

(e) Digital subtraction pulmonary angiography is the investigation of choice for patients with suspected massive PE.

Answer 16

Answers:

(a) Correct

(b) Not correct

(c) Correct

(d) Correct

(e) Not correct

Explanation:

A positive D-dimer test has a poor specificity for PE, especially in hospitalized patients. CTPA or echocardiography is the investigations of choice in case of massive PE.

Question 17

12. When a solitary pulmonary nodule is seen on computed tomography (CT), which of the following radiological features suggested it is benign? (T/F)

(a) Amorphous calcification within the nodule.

(b) Air bronchograms within the nodule.

(c) CT attenuation of – 10 Hounsfield units (HU).

(d) Lobulated outline of the nodule.

(e) Enhancement of the nodule by less than 15 HU following intravenous contrast.

Answer 17

Answers:
(a) Not correct
(b) Not correct
(c) Correct
(d) Not correct
(e) Correct

Explanation:
Popcorn type calcification indicated benignity and is typical of hamartoma.

Amorphous calcification is seen in upto7% of lung carcinomas.

Air bronchograms may be seen within a tumour mainly bronchoalveolar carcinoma.

Lobulated outline and corona radiate on CT are typical of carcinoma

Question 18

34. The following statements regarding pulmonary hamartomas are correct: (T/F)

(a) 5-10% undergo malignant transformation.

(b) Calcification is seen in 30-35%

(c) 80% are located endobronchially.

(d) Central fat density is identified on Ct imaging.

(e) 95% are identified in patients over 40 years.

Answer 18

Answers:
(a) Not correct
(b) Correct
(c) Not correct
(d) Correct
(e) Correct

Explanations:

Pulmonary hamartomas are purely benign lesions with 90% presenting as intrapulmonary lesions within 2 cm of the pleura. Less than 10% of lesions are endobronchial.

Question 19

38. Which of the following are correct regarding squamous cell carcinoma (SCC) at the lung: (T/F)

(a) Is the commonest long tumour to cavitate.

(b) Has the highest incidence of distant metastases.

(c) Is the most likely cell type to cause a Pancoast tumour.

(d) Is the most likely cell type to cause superior venous obstruction.

(e) Is most often centrally located.

Answer 19

Answers:
(a) Correct
(b) Not correct
(c) Correct
(d) Not correct
(e) Correct

Explanation:

Lung SCC has lowest chances of distant metastasis.
Small cell carcinoma is most likely to cause superior venous obstruction.

Question 20

@# 42. Which of the following are correct concerning lymphoma: (T/F)

(a) Lymph node calcification occurs.

(b) Hodgkin’s disease is more common in the chest than non-Hodgkin’s disease.

(c) Posterior mediastinal lymph nodes favour lymphoma rather than Sarcoidosis.

(d) Intrapulmonary lymphoma can present with massive pneumonia – like lobar infiltrates.

(e) Miliary nodules can be the presenting appearance on chest X-Ray.

Answer 20

Answers:
(a) Correct
(b) Correct
(c) Not correct
(d) Correct
(e) Correct

Explanation:
In lymphoma anterior mediastinal lymph nodes are seen.

Question 21

47. The following statements regarding alveolar cell carcinoma are correct: (T/F)

(a) Air bronchograms are a feature of both forms.

(b) Growth is rapid.

(c) It is associated with underlying pre-existing lung fibrosis.

(d) The diffuse pneumonic form is commoner than the local mass form.

(e) It is usually located subpleurally.

Answer 21

Answers:
(a) Correct
(b) Not correct
(c) Correct
(d) Not correct
(e) Correct

Explanation:
Doubling time of alveolar cell carcinoma is longer than 18 months, thus slow growing.
Local mass form is more common. Pneumonic form accounts for 10% - 40 %.?

Question 22

48. The following statements regarding lymphangitis carcinomatosis are correct: (T/F)

(a) Chest X-Ray appearances are of multiple reticulonodular opacities.

(b) It is associated with gastric cancer.

(c) Kerley A and B lines are seen.

(d) Radiological changes usually precede symptom onset.

(e) Hilar adenopathy is seen in 80-90%

Answer 22

Answers:
(a) Correct
(b) Correct
(c) Correct
(d) Not correct
(e) Not correct

Explanation:
Lymphangitis carcinomatosis presents with shortness of breath before radiological changes.

Hilar adenopathy is seen in 20% - 50%.

Question 23

2. Which of the following are correct regarding thoracic trauma: (T/F)

(a) A normal erect CXR virtually exclude acute thoracic aortic injury.

(b) Uncomplicated pulmonary contusion on CXR begins to resolve after at least 7 days.

(c) Air bronchograms are a common CXR feature of pulmonary contusion.

(d) Pulmonary lacerations appear as ovoid lucent areas.

(e) Main bronchial injuries are more common than tracheal injuries.

Answer 23

Answers:
(a) Correct
(b) Not correct
(c) Not correct
(d) Correct
(e) Correct

Explanation:
Air bronchograms are usually absent in pulmonary contusions as result of blood filling the airways.
Uncomplicated pulmonary contusions begin to resolve after 48-72 hrs. Complete resolution is seen usually by 10-14 days.

Question 24

19. Which of the following are true regarding blunt pulmonary trauma? (T/F)

(a) Pulmonary contusions show radiographic resolution in 48 hours.

(b) Bronchial rupture is always accompanied by pneumothorax.

(c) Traumatic diaphragmatic rupture is more common on the left side.

(d) A normal chest radiograph has a good negative predictive value for aortic rupture.

(e) Aortic rupture most commonly occurs at the aortic root.

Answer 24

Answers:
(a) Correct
(b) Not correct
(c) Correct
(d) Correct
(e) Not correct

Explanations:
Bronchial rupture is frequently (70%), not always associated with pneumothorax. The falling lung sign is typical and refers to displacement of lung to the dependant position.
Aortic rupture is the most common at ductus arteriosus level.

Question 25

13. Which of the following are true regarding malignant mesothelioma? (T/F)

(a) Selective involvement of the parietal pleura is typical.

(b) Pleural effusions are common.

(c) Chest wall invasion occurs in 12% of cases at presentation.

(d) Circumferential pleural thickening is typical.

(e) It is a cause of hypertrophic osteoarthropathy.

Answer 25

Answers:

(a) Not correct
(b) Correct
(c) Correct
(d) Correct
(e) Correct

Explanation:
Nodular thickening of both parietal and visceral pleura is usual in mesothelioma.

Question 26

27. Which of the following are correct regarding Thymic carcinoma: (T/F)

(a) Commonly presents with myasthenia gravis.

(b) Extrathoracic metastases are an early feature.

(c) The most common histology is adenocarcinoma.

(d) Calcification is a recognized finding.

(e) Vascular invasion on CT distinguishes thymic carcinoma from lymphoma.

Answer 26

Answers:

(a) Not correct
(b) Not correct
(c) Not correct
(d) Correct
(e) Not correct

Explanation:
Thymic epithelial tumours are of three types;

benign thymoma,

type 1 malignant thymoma (showing local invasion or metastasis)

and type 2 malignant thymoma or thymic carcinoma (showing endothoracic metastasis without extrathoracic involvement).

Thymic carcinoma is rarely associated with paraneoplastic syndromes like myasthenia gravis, pure red cell aplasia and hypogammaglobulinaemia.

Various histopathological types are squamous cell (epidermoid 36%), lymphoepithelioma like (poorly differentiated squamous cell 32%), undifferentiated (anaplastic 11%), small cell (8%), basaloid (4%), sarcomatoid (4%), clear cell (2%), mucoepidermoid (2%), carcinoma and adenocarcinoma (1%).

Question 27

39. Which of the following are correct regarding bronchogenic cysts: (T/F)

(a) They are associated with spina bifida.

(b) Mediastinal bronchogenic cysts account for 85-90%.

(c) They may contain air fluid levels.

(d) Mediastinal bronchogenic cysts are more common on the left.

(e) Intrapulmonary bronchogenic cysts are found more commonly in the lower lobes.

Answer 27

Answers:

(a) Correct
(b) Correct
(c) Correct
(d) Not correct
(e) Not correct

Explanation:
Mediastinal bronchogenic cysts are more common on the right side.
Intrapulmonary cysts are more common in upper lobes.

Question 28

4. Which of the following statements are correct?

(a) The normal thymus in a child is hypoechoic relative to the liver.

(b) The thymus is highly vascular on color Doppler ultrasound.

(c) The thymus arises from the third and fourth branchial pouches.

(d) Teratomas comprise the most common anterior mediastinal mass in childhood.

(e) Thymolipomas are common causes of thymic enlargement in childhood.

Answer 28

Answers:
(a) Correct
(b) Not correct
(c) Correct
(d) Not correct
(e) Not correct

Explanation:
Normal thymus is hypovascular on color Doppler. Thymic hyperplasia is the most common anterior mediastinal mass in childhood. It may be secondary to hyperthyroidism, myasthenia gravis and rebound growth following illness or stress. Thymomas and Thymolipomas are extremely rare in childhood. Neoplastic involvement is usually secondary to infiltration by leukemia or lymphoma.

Question 29

11. Which of the following are correct regarding bronchopulmonary sequestration: (T/F)

(a) Intralobar sequestration (IS) typically presents in the neonatal period.

(b) Extralobar sequestration (ES) is more common than intralobar sequestration.

(c) The main blood supply is form bronchial arteries.

(d) Most commonly affect the lower lobes.

(e) Can cause recurrent chest infection in adults.

Answer 29

Answers:
(a) Not correct
(b) Not correct
(c) Not correct
(d) Correct
(e) Correct

Explanation:
Bronchopulmonary sequestration is a non-functioning sequestered lung segment which has no communication with the tracheobronchial tree and has a systemic blood supply.

Supply is commonly from a separate branch from the aorta and sometimes from upper abdominal vessels or coronary arteries.

IS is more common (80%) and ES is found in (20%).

IS typically presents in adulthood and is often an incidental finding.

Question 30

14. Which of the following are true regarding round pneumonia? (T/F)

(a) It is most commonly associated with Klebsiella infection.

(b) It occurs most commonly in the second and third decades of life.

(c) It is more common in the upper lobes.

(d) It frequently progresses to cavitation.

(e) It is a feature of Q-fever infection.

Answer 30

Answers:
(a) Not correct
(b) Not correct.
(c) Not correct.
(d) Not correct.
(e) Correct.

Explanation:
It is most commonly associated with Streptococcus pneumonia.

Round pneumonia occurs most frequently in children within first decade of life.

It is usually seen in lower lobes, often abutting pleural space.

Round pneumonia evolves rapidly over a few days into segmental consolidation (sometimes with air bronchograms).

Cavitation is unusual

Question 31

17. Which of the following are correct regarding congenital diaphragmatic hernias (T/F)

(a) Most congenital hernias are of the Morgagni type

(b) Defective closure of the pleuroperitoneal membranes leads to a Bochdalek hernia

(c) Right sided hernias may have a delayed presentation

(d) Bochdalek hernias are usually left sided

(e) Congenital cystic adenomatoid malformation is a differential diagnosis

Answer 31

Answers:
(a) Not correct
(b) Correct
(c) Correct
(d) Correct
(e) Correct

Explanation:
Bochdalek hernia is most common congenital hernia (85%-90%). Morgagni type is seen in 10%-15% of the cases.

Question 32

18. Which of the following are correct regarding congenital lobar emphysema (T/F)

(a) It commonly affects the lower lobes

(b) Bilateral involvement is rare

(c) It typically presents in the perinatal period.

(d) Underlying vascular markings are present

(e) The affected lobe is opaque after birth

Answer 32

Answers:
(a) Not correct
(b) Correct
(c) Not correct
(d) Correct
(e) Correct

Explanation:
Congenital lobar emphysema most commonly affects left upper lobe. Lower lobes involvement is seen in only 2 %. In 25% cases, presentation is not seen in perinatal period.

Question 33

26. Features of Swyer-James syndrome include: (T/F)

(a) Increased lucency of a hemithorax

(b) Increased hilar markings, with peripheral pruning

(c) Mild bronchiectasis

(d) Air trapping during expiration

(e) Typically a lobar or segmental distribution

Answer 33

Answers:
(a) Correct
(b) Not correct
(c) Correct
(d) Correct
(e) Not correct

Explanation:
Swyer-James syndrome is a rare lung condition that manifests as unilateral hemithorax lucency as a result of postinfectious obliterative bronchiolitis. It is generally characterized on radiographs by a unilateral small lung with hyperlucency and air trapping. Diminished vascular markings are seen.

Question 34

32. Which of the following are correct regarding pulmonary sequestration:

(a) 70-80 % of cases area intra-lobar

(b) Usually communicates with the tracheobronchial tree.

(c) The majority present in the first 6 months of life.

(d) Blood supply is from the pulmonary arteries

(e) The posterior part of the left lower lobe is most frequently involved

Answer 34

Answers:
(a) Correct
(b) Not correct
(c) Not correct
(d) Not correct
(e) Correct

Explanation:
Pulmonary sequestration is a congenital abnormality consisting of non-functioning primitive lung tissue not communicating with tracheobronchial tree. Intralobular form is more common and presents in adulthood with recurrent chest infections and high output cardiac failure. The blood supply is systemic, mostly from descending thoracic aorta. Contrast enhancement at the same time as thoracic aorta is characteristic on CT.

Question 35

33. The following are correct regarding umbilical catheters in neonates: (T/F)

(a) Typically, there are two umbilical veins and one umbilical artery.

(b) Arterial catheters initially go caudally and posteriorly before coursing cephalad.

(c) Venous catheters follow an anterior and cephalad course

(d) The tip of a venous catheter should be placed below the right atrium

(e) Portal vein gas is a bad prognostic sign

Answer 35

Answers:
(a) Not correct
(b) Correct
(c) Correct
(d) Correct
(e) Not correct

Explanation:
Typically there are two umbilical arteries and one umbilical vein. Air may be introduced inadvertently in intrahepatic portal venous system at time of umbilical venous catheter insertion. This is usually transient.

Question 36

36. Which of the following are correct regarding ventilation / perfusion imaging: (T/F)

(a) The 99Tc-DTPA aerosol scan is performed before the perfusion study.

(b) 81m-Krypton is the cheapest available aerosol for ventilation scanning.

(c) Severe pulmonary hypertension is a contraindication to ventilation / perfusion scanning.

(d) For the perfusion scan, the patient must remain in position for 15-20 minutes before particles become fixed in the lungs.

(e) Blood should be drawn into the syringe prior to injection of radioisotope for perfusion scanning.

Answer 36

Answers:
(a) Correct
(b) Not correct
(c) Correct
(d) Not correct
(e) Not correct

Explanation:
81m-Krypton is expensive with limited availability, but allows for a simultaneous V/Q scan.
Blood should not be drawn prior to injection of isotope to prevent clumping.
The patient should be in position for 2-3 minutes and then imaged in sitting position.