What is Spiral (Helical) CT Scanning

Technological breakthroughs in 1990 gave rise to this existing and revolutionary technique bringing a new diagnostic era in medical imaging.
The term " Spiral CT " is derived from the shape of the path taken by X-ray beams during scanning. Because the examination table advances at a constant rate through the gantry while the X-ray tube rotates continuously around the patient, the X-ray beam traces a Spiral path through the patient. Hence creating a configurous / volumetric data acquisition without Spatial or temporal gaps.
Hence Spiral CT offers two distinct Advantages over routine Axial Scan.

Highspeed

Almost 8-10 times faster. Recently introduced Scanners are subsecond multislice Multiplain Scanners, faster above our imaginations.

Volumetric data acquisition

Which is not possible on Axial CT where slice data acquisition in Axial or Coronal plains, is only acquired as there is no continuous tube rotation or continuous table movement possible. Hence with CT Spiral there is real time 3D reconstruction is acquired.
A Slip ring assembly gantry with refined solid state detectors acquiring multipoint multiplane data, High tube capacity going almost up to 7 MHU in high end machines with enhanced X-ray generators and extremely powerful computers has made this technology possible.

Applications

• All Routine Axial Scans are done at faster speed, hence useful for paediatric and critically ill patients Significantly better resolution and reduced motion and respiratory artifacts.
• With continuous Helical Scanning technique in Chest, Abdomen, in a single breath hold large area coverage is done, hence chances of missing a smallest of the lesions like small pulmonary nodule or small hepatic lesion are almost nil.Respiratory artifacts causing misinterpretation is almost nil. Extremely useful in tracheal and laryngeal study.
• Biphasic imaging - a new technique especially in Abdomen has revolutionized the diagnostic ability in oncology of picking smallest of the lesions in Liver, Pancreas, Kidney etc. Scan is done in Arterial and late venous phase, where enhancement pattern of different lesions differ and hence differentiating of lesions like Hepatomas, Small Mets, regenerating nodules becomes easily possible. Here added interventional Spiral CT is more useful with injection in Spleen or selective injection in Hepatic Artery of Portal Vein, where smallest of the lesions can be picked up very early.
• HRCT - For interstitial Lung diseases high resolution CT with Lung window is a must for differentiation of different lesions. Helical CT is better here.
• 3D Reconstructions - Due to volumetric real time data acquisition by Spiral CT as mentioned before real time 3D reconstructions are possible, represented in various sequences, like 3D surface M.I.P., H.D.M.P. and Rasum are very much useful in conditions like fracture, dislocation at various joints, especially Hip, TM joints, Shoulder joints, in bony tumors, disc lesions, infections and has proved to be a boon for Reconstruction Plastic surgeons in planning their surgeries in conditions like facial trauma etc. It is also useful in areas like Tumors, Strictures or Injuries.
• CT Angiography/Venography - is a real time noninterventional safe procedure with intervenous contrast with 3D sequences like SSD, 3D MIP and 2D MIP with demonstrations of adjacent bony landmarks with visualization of wall calcification (which has significant clinical importance) is proved better over other modalities Internationally in certain areas of body. Contrast is injected through cubital vein by pressure injector and with specific scan delays different Angios are performed.

Cerebral Angio :-

Carotid Angio :-

Aorta, IIiac Vessels :-

Renal Angio :-

Peripheral Angios can also be done quickly and effortlessly

CT Endoscopy (Navigator) :-