Advances in CT Technology

UNDERSTANDING MULTISLICE

With each rotation, it produces higher

simultaneous 0.5 mm slices and gives isotropic

volumetric data with a better resolution .

Thin-slice volume data reconstructed .

Post processing and advanced visualization algorithms allow the

extraction of specific body parts.

Allow to understand complex anatomy and diseases

Open new clinical possibilities.

Uncompromised image quality at a level never seen

before

ADVANTAGES WITH MULTI SLICE CT SCANNERS

New with Multislice CT ScannersCT Angiography (CTA)

Coronary CT Angiography (CCTA)

Visualization of Cardiac and Other Structures

Cardiac Calcium Scoring

Routine CT Scanning with better resolution

Virtual Bronchoscopy

Virtual Colonoscopy

CT Angiography (CTA)

With ultra fast scanning, arteries serving the brain ,lungs, kidneys, arms and legs can be evaluated non-invasively.

Clinical Indications for CT Angiography

Cerebral aneurysm

Carotid stenosis

Pulmonary embolism

Renal artery stenosis

Aortic aneurysm/dissection

Mesenteric ischemia

Hepatic artery anatomy (for surgery)

Lower extremity arterial runoff for PVD or nonhealing wounds

CTAngiography - technique

• BOLUS TRACKING • Amount and rate of contrast injection• Exposure factors• Pitch/collimation

COLLIMATION

ROTATION TIME/PITCH

CONTRAST (ml)

RATE OF INJECTION

TIME TAKEN

AORTOGRAM 0.6 mm 0.33/1 80 +20 4.5 ml 12 sec

CAROTID AND CEREBRAL

0.6 mm 0.33/0.7580 +20 4.5 ml

6 sec

RENAL ANGIOGRAPHY

0.6 mm 0.33/0.7580 +20 4.5 ml

5 sec

PULMONARY 0.6 mm 0.37/0.7580 +20 4.5 ml

5 sec

PERIPHERAL RUN OFF

0.6 mm 0.37/1 100 + 404.5 ml

27 sec

64 SLICE MDCT

• Dissection flap at the root of aortaNormal

• ANEURYSM

• CT- Large saccular ascending aortic aneurysm 7cm diam,2.5cm eccentric thrombus, L=10.5 cm. origin of brachiocephalic, carotid, subclavian Artery from sac and e/o narrowing of ostium. Mild compression of main and left pulmonary artery. Mild pericardial effusion.

ABDOMINAL ANEURYSM

DISSECTION

• There is extensive thrombosis of infrarenal segment of aorta, extending upto its bifurcation; into both common iliac arteries causing total block in aorta and only minimal opacification of common ileac arteries bilaterally.

• Left renal artery is also blocked.• Left kidney is small in size.• Inferior mesenteric artery is not opacified.• Bilateral external and internal iliac arteries reveal good contrast opacification from collateral of lumbar, intercoastal and

inferior epigastric arteries.• Its superior ventral branches (i.e) coeliac and superior mesenteric artery are normal.• Right renal artery is normal.• CT scan of reveal Lehriche’s syndrome seen as block in infra renal abdominal aorta with blocked left renal artery.

Aortoarteritis

• K/c/o Erythema nodosum with intermittent cluadication in both lower limb.

• CT Angiogram of both lower limb:• Rt lower limb- There is 1cm sized

significant stenosis (65-70%) of proximal right common iliac artery due to concentric noncalcific wall plaque. It is approx 2.8 cms from it’s origin.

• Lt lower limb- There is mild focal narrowing (30%) at the origin of left common iliac artery due to eccentrically placed irregular noncalcific plaque.

• 3.7X6.1X5.5 cms sized pseudoaneurysm is seen at the site of distal anastomosis of the graft with the popliteal artery.

• There is small eccentric fusiform dilatation of upper abdominal aorta. Stent is seen in situ in bilateral renal artery with no instent restenosis.

C/H-vomiting and severe headache since 2 days. CT scan showed subarachnoid hemorrhage.CT brain angiogram of circle of Willis-a 2x2cms sized pyramidal shaped aneurysm with ‘tit’ seen in region of Acom artery. no other vascular abnormality is seen.

• CH -: Scalp cirsoid aneurysm. • CT- A large swelling in left parietal scalp region caused predominantly by tortous dilated

vessels having being supplied predominantly by left external carotid artery resulting in extensive spread out network of abnormal small and large vessels seen all along left half of scalp, with large draining veins seen draining into superior ophthalmic vein, left jugular ( external / internal ) vein, angular and facial veins.

• Tortous enlarged ophthalmic vein in left orbit noted. • Posteriorly along scalp is noted enlarged posterior auricular, retro-mandibular and deep

cervical veins.

• H/O-Road traffic accident with pseudoaneurysm in the innominate artery which was stented with FLUENCY plus vascular stent graft. 12mmx60mm{56mm covered graft material}.post deployment arch aortogram shows minimal endoleak into the false aneurysm.

• Repeat CT-shows stent in innominate with leak in proximal aspect of innominate artery{type 1} .Patchy thrombosed lumen noted around the stent.

• Good distal opacification of innominate,right subclavian/common carotid artery noted.

Coronary Angiography

VIRTUAL COLONOSCOPY

Virtual Colonoscopy

• Emerging noninvasive imaging technology for detecting colon polyps and cancer.

• Trends towards using this as screening gold standards as it permits complete visualization of the entire colon, hence providing the opportunity to identify precancerous polyps and cancer.

• Accepted applications include incomplete colonoscopy.

Advantages• More comfortable• No sedation is needed• Evidence that CTC is better

able to detect polyps than fecal occult blood testing, barium enema, and sigmoidoscopy.

• Takes less time than either a conventional colonoscopy or a lower GI series.

• Secondary benefit of revealing diseases or abnormalities outside the colon.

• Disadvantages-• Inability to take tissue samples or remove polyps• Polyps smaller than between 2-10 mm may not be

seen.• Ionizing radiation.

BUT It should be remembered than between 10% and 20% of all polyps and up to 5% of colon cancers are missed even on conventional colonoscopy.

VIRTUAL BRONCHOSCOPY

Virtual Bronchoscopy• Virtual bronchoscopy produces high- resolution images of the tracheobronchial tree and endobronchial views that simulate the findings at conventional

bronchoscopy.APPLICATIONS

Normal Anatomic Features & Varients

Tracheobronchial Stenosis

Bronchogenic Carcinoma

Endoluminal Lesions

Foreign Body Aspiration

Imaging Guidance

Tracheoesophageal Fistula

Burn Injuries

Stent Planning and Follow-up

Trauma

Normal Anatomic Features

• 3D CT can depict the airway down• to the sixth- and seventh-order subdivisions. • This 3D map can be used to guide• bronchoscopy or to direct transbronchial needle• Biopsy.

Tracheobronchial Stenosis

• The stenosis-to-lumen ratios determined with VB and conventional bronchoscopy were found to be within 10% of each other.

• Especially valuable for evaluation of suspected tracheobronchial stenosis in children.

• Less invasive and safer than fiberoptic bronchoscopy.

• The advantage of depicting the adjacent structures such as vascular rings, which can be a cause of stridor in children.

Bronchogenic Carcinoma

• CT is the primary imaging technique for the detection, staging, and follow-up of primary malignant tumors of the lung.

• CT with VB • Sensitivity -100% for obstructive lesions 16% for mucosal lesions 90% for endoluminal lesions.

• Specificity for malignant tumours - 100%.

Advantage of VB over fiberoptic bronchoscopy

• Can image beyond the site of obstruction

• Visualization of the smaller airways, which are not accessible with fiberoptic bronchoscopy.

Endoluminal Lesions

Foreign Body Aspiration

Imaging Guidance

Tracheoesophageal Fistula

Burn Injuries

Stent Planning and Follow-up

Trauma

Other Potential Applications.

TO CONCLUDE…New technology proving its worth:

In routine scanning

In more specialised fields

CT scanning procedure may:

– be more comfortable for the patient

– carry fewer risks of complications

– sometimes replace more invasive procedures

• CT doses:

– higher for some exams but could be lower for others

– thin slice doses multi- slice lower than on 4-slice

– are being addressed by dose reduction features

DISCLAIMER

Thank you…