The term ‘Computerised Cephalometrics’ entails using advanced specialised software through computers to make cephalometric measurements for quick and accurate analysis and store data for ease of retrieval and transfer.

The development of computerised cephalometrics is closely linked to the evolution of digital radiology in medicine and dentistry, including orthodontics.

The simplest version of computerised analysis software is the one that substitutes the use of a protractor and ruler to make measurements of craniofacial angular/linear measurements and ratios without making any lines on a cephalogram. These digital cephalometric systems developed in the 1970s–1980s used ‘Disc Operating Systems’ (DOS) and had limited data analysis and treatment planning capabilities. These systems were then upgraded to be compatible with Windows and Mac systems with several advanced functions based on complex programming algorithms.

Computerised cephalometrics has since then advanced with newer developments in computer hardware technology, image capture (scan) and image transfer, and on-screen image quality of the visualising medical grade high-resolution monitor screens. During the early days, software used by the architecture engineers was inducted to make measurements in the cephalometric analysis. Although most cephalometric analysis software were designed for 2D measurements, the more sophisticated specific software programs were later developed for the reconstruction of 3-D images for the 3D studies of the face and craniofacial structures through CT scans and, lately, cone beam computed tomography (CBCT), including intra-oral and soft tissue scans of the face.

Robert Murray Ricketts spent a significant amount of his lifetime developing computerised cephalometric systems and integrating growth prediction data and visual treatment objectives (VTO). He was the pioneer and known as the father of computerised orthodontics. The automated cephalometric systems were developed in collaboration with Rocky Mountain Orthodontics in Denver, Colorado, USA.

The advancements in computer technology helped to render quality, accuracy and speed to image (cephalometric image) management. The enhanced knowledge in growth and soft tissue behaviour following orthodontic treatment and orthognathic surgery has been of immense help in orthodontic treatment planning, predictions of growth and simulation of orthognathic surgery. Technological advancements in computer technology, digital image manipulation and research in orthodontic literature continue to pour in and are being integrated to update and enhance computerised cephalometrics ‘capabilities’, speed and accuracy.

Computerised cephalometrics often need to be clarified with digital cephalometrics. Digital cephalometrics primarily involves recording a cephalometric image on a non-film medium as a ‘digital image’, which is manipulated through computers and viewed on screen. It substitutes analogue film with the digital image. After calibration, the digital cephalometric image can be imported into cephalometric software ( Tables 33.1 and 33.2 ) for analysis.

Computer discs are a medium for storing and retrieving ‘digital images’ obtained or recorded through complementary metal-oxide-semiconductor (CMOS) or charged couple device (CCD) sensors or storage phosphor plates. Digital radiology image achieved through the photostimulable phosphor plate (PSP) is called computed radiography (CR), while radiology images obtained on CCD/CMOS sensors and processed on screen are called direct digital radiography (ddR).

The cephalogram requires to be available as a digital image for processing onscreen computerised analysis. These images may be available directly when acquired through a digital cephalostat and alternatively analogue X-ray films can be scanned or captured through digital camera.

The cephalometric software mainly locates the X and Y coordinates of a cephalometric point, and this information is sent to the computer software and the relative position, planes and angles can be calculated through algorithms.

The location of the X-Y coordinate of a point can be performed through a ‘Digitiser’ using the digitising tablet and a cursor. The cephalogram film or tracing is placed on a ‘Digitiser’, backlit, using soft light. The points are digitised using a crossbar, which is a digitising pen. Such a process is called indirect digitisation. Using on-screen or direct digitisation involves marking cephalometric landmarks on the computer screen, and this technology has replaced digitisation through the digitiser.

The second option involves digitising cephalometric points on a computer monitor screen with a mouse cursor. The on-screen image may be obtained through indirect acquisition (scan or digital picture of a cephalogram), direct acquisition methods, or digital radiography (dR/or ddR).

Contemporary software programs can dynamically manipulate digital images through various image processes and tools, such as changing algorithms and windowing. These processes permit the alteration of the contrast and density of the image without causing permanent changes to the original file. These options allow for the creation of various image effects that can be used in a variety of contexts, including the precise location of landmarks. The raw data images can be preserved and used as and when needed.

Optimisation is the crucial word in digital imaging, which means that digital computerised radiographic imaging and direct digital imaging have superior capabilities to optimise each function, from image production, image display, archiving and image retrieval, which are independent developments. The term ‘optimisation’ lies at the crux of digital imaging. Such advancements in digital imaging technology have revolutionised how we process and visualise images, offering unparalleled precision and accuracy. The synergistic and multitasking outcome of these capabilities has significantly enhanced diagnostic capabilities in radiodiagnosis.

The limitations of conventional cephalometry and the advantages of computerised cephalometry are given in Table 33.1 .

Radiological image quality standards for all medical applications, including workflow and data management, have been set up by the American College of Radiology and National Electrical Manufacturers Association (NEMA) USA and are followed worldwide. Digital imaging and communications in medicine (DICOM) standard involves handling, storing, printing and transmitting information in medical imaging. The copyrights of the DICOM standard are with the National Electrical Manufacturers Association (NEMA) USA. DICOM systems can be connected on workflow through a local area network (LAN), a wide area network (WAN) or a picture archiving and communication system (PACS). WAN is a geographically dispersed telecommunications network. The term distinguishes a broader telecommunication structure from a LAN. PACS is a network of computers for radiology input data for display and storage.

Various cephalometric analysis software and hardware systems have been developed to calculate the cephalometric values once suggested points are located. The analysis and other software capabilities have progressed significantly since indirect digitisation, where an analogue film was kept on a digitiser, and X-Y coordinates for the points were digitised. One such system was developed in the early 1990s in Delhi in a collaborative effort between IIT and the Orthodontic Department at AIIMS. It was named DIGI-CEPH ( Fig. 33.1 ). It was a DOS-based system. Later systems utilised better hardware and software where digitisation could be undertaken on a screen using the digital cephalometric image.

Computerised cephalometrics using direct digitisation.

(A) On-screen menu of DIGI-CEPH. (B) A digitiser is used to locate the X-Y coordinate connected to a computer. The points to be digitised are chosen for the required analysis on screen through the software function. Point mode allows the placement of a single point, while stream mode is used to draw profiles or contours. Cephalometric software, such as DIGI-CEPH, calculates the variables and stores the data. The data are retrieved on screen or printed in a tabular form. A plotter or laser printer can print a graphic display of the profiles. Close-up of backlit digitiser showing switches for different modes of digitisation. The crossbar of the digitiser cursor is used to locate the cephalometric points either on the X-ray tracing or directly on the film placed on a backlit box. (C) Graphics display of skeletal and facial contours generated through DIGI-CEPH.

AutoCEPH ( http://ci.csio.res.in ) is a software for analysing cephalometric data developed by the Central Scientific Instruments Organisation (CSIO) in collaboration with the Orthodontic Department at All India Institute of Medical Sciences (AIIMS) in New Delhi. This simple software offers on-screen digitisation abilities, automated analyses and comparisons with a selected ethnic group. It can generate data on 16 standard lateral analyses in a fraction of a second after cephalometric points are digitised by the orthodontist. AutoCEPH can also create superimposition and graphic presentation of profiles ( Fig. 33.2 A–D).

AutoCEPH ( http://ci.csio.res.in ) was developed as an advanced version of DIGI-CEPH by scientists and clinicians at CSIO Chandigarh and Orthodontic Division at Centre for Dental Education and Research All India Institute of Medical Sciences, New Delhi.

(A and B) AutoCEPH can carry out 16 standard lateral cephalometric analyses and provides various tools for accurately marking anatomical landmarks. Its unique features include viewing the uploaded X-ray in different pseudo-colours (yellow in this image) for precise marking of landmarks. There is a special feature for marking a landmark in a zoomed-up window. ( C, D ) The analysis application generated the AutoCEPH report after marking all the landmarks required for a particular analysis. Various parameters were computed along with their values, and patient details and cephalogram can be viewed in the report. The report may also be printed or exported to other file formats as desired.

More advanced software(s) have several functions, such as growth prediction, orthognathic surgical planning and simulation of treatment results. These functions and outputs have inherent limitations for accuracy. With the induction of cone beam, CT in orthodontics newer software(s) can handle 3D volumetric data for analysis ( Tables 33.3 and 33.4 ).

TABLE 33.4

Classification of cephalometric software based on features and analytical capabilities

Basic software	Advanced software	Network software	Collaborative software
1. Patient’s directory management	1. Superimposition, in addition to basic features	1. Basic features	1. Collaborative platform
2. Image filtering	2. Treatment planning	2. Centralised database and patient image repository management	2. Collaborating partners with sophisticated consultation
3. Image enhancement features	3. Treatment simulation		3. Network features
4. Analyses	4. Orthognathic surgery simulation		4. High bandwidth
5. Analysis viewer	5. Growth prediction
6. Automatic report generation	6. Clinical photography management
7. Standalone application	7. Cross stage comparison
	8. Image export systems
	9. DICOM support

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