Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

More documents

Recommendations

Info

Chapter Two The Thorax 111 tumors, or from heart base masses. Dorsal displacement of the trachea immediately cranial to the bifurcation may be due to right atrial, heart base, or tracheobronchial lymph node masses. Dorsal displacement of the trachea caudal to the tracheal bifurcation occurs with left atrial enlargement. Ventral displacement in that region may be due to esophageal enlargement, periesophageal caudal mediastinal masses, or tracheobronchial lymph node enlargement. The degree of ventral main stem bronchial displacement is more severe with lymph node enlargement than with esophageal lesions. Many esophageal lesions displace both the heart and trachea, while lymph node enlargement affects mostly the trachea and main stem bronchi. Left ventricular enlargement will elevate the trachea at the bifurcation. Mediastinal shifts away from the midline may be detected easily by identifying the trachea’s position. Whether the shift is due to a mass pushing in the direction of the shift or to the collapse of the lung lobe with shifting toward the collapsed side cannot be determined solely from tracheal position. Dorsal displacement of the cranial thoracic trachea may be observed on the recumbent lateral view when pleural fluid is present. This may be due to the displacement that accompanies a cranial mediastinal mass, but it is more often due to a shift in the position of the lungs that occurs in the presence of pleural fluid (or even air). Compression of the tracheal lumen indicates that a mass is present within the pleural fluid. In the absence of tracheal compression, a mass may or may not be present. Tracheal displacement to the left is prevented by the aorta, but it can occur when a right aortic arch is present. Mediastinal shifts that include the heart will permit leftward tracheal displacement. Right-sided displacement of the trachea between the thoracic inlet and bifurcation is seen in many normal dogs and is more pronounced in brachycephalic breeds. True right-sided displacement of the trachea also may occur with heart base masses and esophageal enlargement. Most ventral mediastinal masses displace the trachea dorsally and do not move it to either the right or the left. The tracheal bifurcation may be displaced caudally. In the cat, the tracheal bifurcation almost always is visualized at the sixth intercostal space, and any deviation caudal to this strongly suggests the presence of a cranial mediastinal mass. In dogs, the tracheal bifurcation occurs at the fifth or sixth intercostal space. The possibility of a cranial mediastinal mass should be considered if there is displacement caudal to the sixth intercostal space. Tracheobronchial lymphadenopathy, especially when associated with chronic disease, may cause narrowing as well as displacement of the trachea and main stem bronchi. These are reliable signs of lymphadenopathy, which can be seen despite obliteration of the lymph node margins by a pulmonary infiltrate. T R AC H E A L C O L L A P S E The tracheal diameter may change very slightly with respiration and coughing in normal animals. 204 When marked luminal narrowing occurs during normal or forced respiration, tracheal collapse is present. Although dorsoventral narrowing is most common, congenital side-to-side, or lateral, narrowing may occur. The extent and location of the narrowing will vary. Narrowing of the caudal cervical trachea is more common at inspiration; at expiration intrathoracic tracheal narrowing usually is seen (Figs. 2-87 and 2-88). The narrowing may extend through the thoracic inlet, which probably accounts for some variation. Left atrial enlargement may cause narrowing or collapse of the tracheal bifurcation or main stem bronchi (Fig. 2-89). Both inspiratory and expiratory recumbent lateral radiographs that include the entire trachea should be obtained if tracheal collapse is suspected. Inducing a cough will accentuate the collapse; however, obtaining a radiograph at the time of the cough may be difficult. Fluoroscopic examination is useful in evaluating and documenting tracheal collapse. Contrast studies using intratracheally administered barium or water-soluble iodinated contrast agents have been described. These rarely provide additional useful information beyond that obtained from carefully positioned, properly exposed, survey radiographs. 202,203 A lateral radiograph obtained while the animal’s head and neck are dorsiflexed is recommended for evaluation of tracheal collapse. 204 This view accentuates the tracheal narrowing and may be useful, especially relative to the tracheal diameter at the thoracic inlet.
112 Small Animal Radiolo g y and Ultrasono graphy Fig. 2-87 An 8-year-old male Yorkshire Terrier with a 5-year history of a honking cough. On this lateral radiograph there is marked narrowing of the trachea cranial to the thoracic inlet. This is evident in the radiograph obtained at inspiration. Diagnosis: Extrathoracic tracheal collapse. Fig. 2-88 A 12-year-old male Poodle with harsh lung sounds and respiratory distress, especially when excited. Inspiratory (A) and expiratory (B) lateral thoracic radiographs were obtained. The trachea appears normal on A. On B the entire intrathoracic trachea narrows markedly. There is extensive calcification of the tracheal rings. The left atrium is enlarged. Diagnosis: Intrathoracic tracheal collapse. A B
Page 1 and 2:
SAUNDERS An Imprint of Elsevier Sci
Page 3 and 4:
C H A P T E R O N E Introduction GE
Page 5 and 6:
Chapter One Introduction 3 Fig. 1-1
Page 7 and 8:
metal. Soft tissues or organs surro
Page 9 and 10:
Inadequate penetration will result
Page 11 and 12:
Chapter One Introduction 9 signal i
Page 13 and 14:
Chapter One Introduction 11 previou
Page 15 and 16:
Chapter One Introduction 13 Mach ba
Page 17 and 18:
Chapter One Introduction 15 malitie
Page 19 and 20:
Chapter One Introduction 17 indicat
Page 21 and 22:
Chapter One Introduction 19 Fig. 1-
Page 23 and 24:
Chapter One Introduction 21 Fig. 1-
Page 25 and 26:
Chapter One Introduction 23 24. Lev
Page 27 and 28:
26 Small Animal Radiolo g y and Ult
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62: 60 Small Animal Radiolo g y and Ult
Page 91 and 92: A B C Fig. 2-63 A 10-year-old male
Page 101 and 102: 100 Small Animal Radiolo g y and Ul
Page 111: 110 Small Animal Radiolo g y and Ul
Page 129 and 130: Fig. 2-101 A 7-year-old male mixed
Page 163 and 164:
162 Small Animal Radiolo g y and Ul
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
Page 209 and 210:
Page 211 and 212:
Page 213 and 214:
Page 215 and 216:
Page 217 and 218:
Page 219 and 220:
Page 221 and 222:
Page 223 and 224:
Page 225 and 226:
Page 227 and 228:
Page 229 and 230:
Page 231 and 232:
Page 233 and 234:
Page 235 and 236:
Page 237 and 238:
Page 239 and 240:
Page 241 and 242:
Page 243 and 244:
Page 245 and 246:
Page 247 and 248:
Page 249 and 250:
Page 251 and 252:
Page 253 and 254:
Page 255 and 256:
Page 257 and 258:
Page 259 and 260:
Page 261 and 262:
Page 263 and 264:
Page 265 and 266:
Page 267 and 268:
Page 269 and 270:
Page 271 and 272:
Page 273 and 274:
Page 275 and 276:
Page 277 and 278:
Page 279 and 280:
Page 281 and 282:
Page 283 and 284:
Page 285 and 286:
Page 287 and 288:
Page 289 and 290:
Page 291 and 292:
Page 293 and 294:
Page 295 and 296:
Page 297 and 298:
Page 299 and 300:
Page 301 and 302:
Page 303 and 304:
Page 305 and 306:
Page 307 and 308:
Page 309 and 310:
Page 311 and 312:
Page 313 and 314:
Page 315 and 316:
Page 317 and 318:
Page 319 and 320:
Page 321 and 322:
Page 323 and 324:
Page 325 and 326:
Page 327 and 328:
Page 329 and 330:
Page 331 and 332:
Page 333 and 334:
Page 335 and 336:
Page 337 and 338:
Page 339 and 340:
Page 341 and 342:
Page 343 and 344:
Page 345 and 346:
Page 347 and 348:
Page 349 and 350:
Page 351 and 352:
Page 353 and 354:
Page 355 and 356:
Page 357 and 358:
Page 359 and 360:
Page 361 and 362:
Page 363 and 364:
Page 365 and 366:
Page 367 and 368:
Page 369 and 370:
Page 371 and 372:
Page 373 and 374:
Page 375 and 376:
Page 377 and 378:
Page 379 and 380:
Page 381 and 382:
Page 383 and 384:
Page 385 and 386:
Page 387 and 388:
Page 389 and 390:
Page 391 and 392:
Page 393 and 394:
Page 395 and 396:
Page 397 and 398:
Page 399 and 400:
Page 401 and 402:
Page 403 and 404:
Page 405 and 406:
Page 407 and 408:
Page 409 and 410:
Page 411 and 412:
Page 413 and 414:
Page 415 and 416:
Page 417 and 418:
Page 419 and 420:
Page 421 and 422:
Page 423 and 424:
Page 425 and 426:
Page 427 and 428:
Page 429 and 430:
Page 431 and 432:
Fig. 3-234 A 7-year-old female Brit
Page 433 and 434:
Page 435 and 436:
Page 437 and 438:
Page 439 and 440:
Page 441 and 442:
Page 443 and 444:
Page 445 and 446:
Page 447 and 448:
Page 449 and 450:
Page 451 and 452:
Page 453 and 454:
Page 455 and 456:
Page 457 and 458:
Page 459 and 460:
Page 461 and 462:
Page 463 and 464:
Page 465 and 466:
Page 467 and 468:
Page 469 and 470:
Page 471 and 472:
Page 473 and 474:
Page 475 and 476:
Page 477 and 478:
Page 479 and 480:
Page 481 and 482:
Page 483 and 484:
Page 485 and 486:
Page 487 and 488:
Page 489 and 490:
Page 491 and 492:
Page 493 and 494:
Page 495 and 496:
Page 497 and 498:
Page 499 and 500:
Page 501 and 502:
Page 503 and 504:
Page 505 and 506:
Page 507 and 508:
Page 509 and 510:
Page 511 and 512:
Page 513 and 514:
Page 515 and 516:
Page 517 and 518:
Page 519 and 520:
Page 521 and 522:
Fig. 4-59 A 9-year-old female Russi
Page 523 and 524:
Page 525 and 526:
Page 527 and 528:
Page 529 and 530:
Page 531 and 532:
Fig. 4-73 A 2-year-old female Saint
Page 533 and 534:
Page 535 and 536:
Page 537 and 538:
Page 539 and 540:
Page 541 and 542:
Page 543 and 544:
Page 545 and 546:
Page 547 and 548:
Page 549 and 550:
Page 551 and 552:
Fig. 4-97 A 10-year-old male mixed
Page 553 and 554:
Page 555 and 556:
Page 557 and 558:
Page 559 and 560:
Fig. 4-107 A 4-year-old male Chow C
Page 561 and 562:
Page 563 and 564:
Page 565 and 566:
Page 567 and 568:
Page 569 and 570:
Page 571 and 572:
Page 573 and 574:
Page 575 and 576:
Page 577 and 578:
Page 579 and 580:
Page 581 and 582:
Page 583 and 584:
Page 585 and 586:
Page 587 and 588:
Page 589 and 590:
Page 591 and 592:
Page 593 and 594:
Page 595 and 596:
Page 597 and 598:
Page 599 and 600:
Page 601 and 602:
Page 603 and 604:
Page 605 and 606:
Page 607 and 608:
Page 609 and 610:
Page 611 and 612:
Page 613 and 614:
Page 615 and 616:
Page 617 and 618:
Page 619 and 620:
Page 621 and 622:
Page 623 and 624:
Page 625 and 626:
Page 627 and 628:
Page 629 and 630:
Page 631 and 632:
Page 633 and 634:
Page 635 and 636:
Page 637 and 638:
Page 639 and 640:
Page 641 and 642:
Page 643 and 644:
Page 645 and 646:
Page 647 and 648:
Page 649 and 650:
Page 651 and 652:
Page 653 and 654:
Page 655 and 656:
Page 657 and 658:
Page 659 and 660:
Page 661 and 662:
Page 663 and 664:
Page 665 and 666:
Page 667 and 668:
Page 669 and 670:
Page 671 and 672:
Page 673 and 674:
Page 675 and 676:
Page 677 and 678:
Page 679 and 680:
Page 681 and 682:
Page 683 and 684:
Page 685 and 686:
Page 687 and 688:
Page 689 and 690:
Page 691 and 692:
Page 693 and 694:
Page 695 and 696:
Page 697 and 698:
Page 699 and 700:
Page 701 and 702:
Page 703 and 704:
Page 705 and 706:
Page 707 and 708:
Page 709 and 710:
Page 711 and 712:
Page 713 and 714:
Page 715 and 716:
I N D E X A Abdomen, abnormal prese
Page 717 and 718:
Index 729 Bone, cysts of, 525-527,
Page 719 and 720:
Index 731 Ear, abscess of—cont’
Page 721 and 722:
Index 733 Hydrocephalus—cont’d
Page 723 and 724:
Index 735 Lungs. See also Pulmonary
Page 725 and 726:
Index 737 Pregnancy, determination
Page 727 and 728:
Index 739 S-shaped aortic deformity
show all

Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Create successful ePaper yourself

Delete template?

Save as template?