I.I. vs. FPD

Pros of FPDsPros of FPDs Low weight and dimension)

Stability through device life

Better image quality

Non ideal trajectory

Irregular sampling stepOff-line calibration requiredOff-line calibration required

A calibration ring phantom with metal beads is used for calibration.

Calibration should be performed for each used scan trajectory, since mechanical distortion is specific

Calibration sets the correct correspondence between 2D projection and 3D position. It is repeated weekly.

Workstation Processing

MIP (Maximum Intensity Projection)

SSD (Surface Shaded Display)

Workstation Processing

Surface vs. Volume Rendering

Virtual Navigator

Workstation Processing

Processing della workstation

Coils and Clips

Calibrated anatomycal measures

Opposite to DSA (Digital Subtraction Angiography), which deletes still objects, this algorithm does reconstruct high contrast objects not moving and varying during the scan and enhances them over the vascular anatomy

Risultati

Immagine DSA standard

Aneurismi multipli dell’arteria carotide interna

Viste ottenute con Volume Rendering (differenti proiezioni)

Aneurismi multipli dell’arteria carotide interna

Dental FPD CT

Giuseppe Gentil, Francesco Maffesanti, Massimo Molinari, 2005/06

Multislice helical CT

scan start

multi-row detector array

trajectory of the rotatingx-ray tube focal spot

direction ofcontinuousbed shift

multi-row detector array

z axismulti-row detector array

Reslicing

Maximum intensity projection

Rendering

Navigation

CRANIOPLASTICS

Application in the field of maxillo-facial surgery-Precise cranial CT scan- Import into specific SW environment; e.g., Mimics (Materialize’s Interactive Medical Image Control System)

- Segmentation of skull- Vectorization into a CAD environment- Design of prosthesis

- Construction by 3D rapid prototiping

GANTRY TILT = 0°

Segmentation by Thresholding

Segmentation by Region Growing and regular contouring by NURBS

Polinomial contours by NonUniform Rational B-Splines (NURBS)

3D

Application: from 3D virtual model to real model by rapid prototyping

Application: design of prosthesis

Rapid prototyping by stereo-lithography

The polymer prototype is not directly used. Conversely, it is used as 3D model for fabrication or to create a mold (it stampo) were the final material is cast .

Final material can be autologous or donor bone, hydroxyapatite, PMMA, Titanium

silicon-rubber mold

La Cranioplastica

I Materiali

I materiali usati finora per la cranioplastica sono stati molteplici, ma molti di loro sono stati abbandonati per diversi motivi: scarsa biocompatibilità,

ridotta maneggevolezza nel modellamento, alto costo…

I materiali maggiormente utilizzati oggi sono:

Osso autologo Titanio

Idrossiapatite PMMA

La Cranioplastica

Tecnica Chirurgica

1. Posizionamento paziente

2. Rimozione adesione pelle–dura madre

La Cranioplastica

3. Applicazione acqua ossigenata (disinfettare e coagulare)

Surgical implant of skull prosthesis

ECG gating for Cardiac CT

Small animal (rat) CT