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Respiratory Gating
Prospective respiratory triggering ver-
sus retrospective respiratory gating
With prospective respiratory triggering, the lung vol-
ume for example is covered in a "step-and-shoot" tech-
nique. The patient's respiratory signal is used to start
sequential scans at a predefined respiratory level of
the patient' s respiratory curve. With retrospective res-
piratory gating, the lung volume is covered continu-
ously by a spiral scan. The patient's respiratory signal is
recorded simultaneously to allow a retrospective selec-
tion of the respiratory level used for image reconstruc-
tion. Prospective respiratory triggering has the benefit
of smaller patient dose than respiratory-gated spiral
scanning, since scan data is acquired at the previously
selected respiratory level only. It does not, however
provide continuous volume coverage with overlapping
slices and misregistration of anatomical details may
occur. Furthermore, reconstruction of images in differ-
ent levels of the respiratory cycle for functional evalu-
ation needs repeated CT examination of each of the
desired respiration levels along the same volume in z-
direction using Prospective Triggering technique. Since
respiratory triggered sequential scanning depends on
a reliable prediction of the patient's next Inspiration
maximum and expiration minimum, the method
should not be used for patients with arrhythmic
breathing and irregular respiratory rates and the affin-
ity to cough and to sigh.
Summary of Contents for SOMATOM
Page 4: ...4 Overview Respiratory Gating 484 Children 508 ...
Page 5: ...Overview 5 ...
Page 121: ...Workflow Information 121 ...
Page 135: ...Contrast Medium 135 ...
Page 157: ...Application Information 157 Program to define capture options ...
Page 161: ...Application Information 161 ...
Page 167: ...Head 167 ...
Page 183: ...Head 183 ...
Page 187: ...Head 187 ...
Page 191: ...Head 191 ...
Page 195: ...Head 195 ...
Page 211: ...Neck 211 ...
Page 217: ...Neck 217 ...
Page 223: ...Shoulder 223 ...
Page 239: ...Thorax 239 ...
Page 249: ...Thorax 249 ...
Page 269: ...Abdomen 269 ...
Page 273: ...Abdomen 273 ...
Page 277: ...Abdomen 277 ...
Page 287: ...Abdomen 287 ...
Page 293: ...Abdomen 293 ...
Page 307: ...Spine 307 ...
Page 311: ...Spine 311 ...
Page 321: ...Pelvis 321 ...
Page 327: ...Pelvis 327 ...
Page 338: ...338 Upper Extremities Hints For image reconstruction of soft tissue use kernel B30s B31s ...
Page 339: ...Upper Extremities 339 ...
Page 342: ...342 Upper Extremities Hint For image reconstruction of soft tissue use kernel B30s B31s ...
Page 343: ...Upper Extremities 343 ...
Page 357: ...Lower Extremities 357 ...
Page 369: ...Vascular 369 ...
Page 375: ...Vascular 375 ...
Page 379: ...Vascular 379 ...
Page 383: ...Vascular 383 ...
Page 387: ...Vascular 387 ...
Page 393: ...Vascular 393 ...
Page 397: ...Vascular 397 ...
Page 401: ...Vascular 401 ...
Page 405: ...Vascular 405 ...
Page 409: ...Vascular 409 ...
Page 413: ...Vascular 413 ...
Page 421: ...Specials 421 ...
Page 423: ...Specials 423 ...
Page 435: ...Specials 435 ...
Page 455: ...Specials 455 CARE Vision and Biopsy layout for CAREView equal size display Biopsy two segment ...
Page 461: ...Specials 461 ...
Page 469: ...Radiation Therapy 469 ...
Page 483: ...Radiation Therapy 483 ...
Page 517: ...Children 517 ...
Page 521: ...Children 521 ...
Page 525: ...Children 525 ...
Page 529: ...Children 529 ...
Page 533: ...Children 533 ...
Page 537: ...Children 537 ...
Page 545: ...Children 545 ...
Page 553: ...Children 553 ...
Page 557: ...Children 557 ...
Page 561: ...Children 561 ...
Page 565: ...Children 565 ...
Page 573: ...Children 573 ...
Page 577: ...Children 577 ...
Page 581: ...Children 581 ...
Page 585: ...Children 585 ...