SECTION 1: SKULL AND BRAIN<br>SCALP, SKULL<br>ANATOMICALLY BASED DIFFERENTIALS<br>4 Skull Normal Variants<br>Miral D. Jhaveri, MD, MBA<br>6 Scalp Mass, Child<br>Luke L. Linscott, MD and Chang Yueh Ho, MD<br>10 Scalp Mass, Adult<br>Miral D. Jhaveri, MD, MBA<br>12 Congenital Anomalies of Skull Base<br>Luke L. Linscott, MD and Chang Yueh Ho, MD<br><br>GENERIC IMAGING PATTERNS<br>18 "Hair on End"<br>Miral D. Jhaveri, MD, MBA<br>20 Thick Skull, Generalized<br>Miral D. Jhaveri, MD, MBA<br>24 Thick Skull, Localized<br>Miral D. Jhaveri, MD, MBA<br>26 Thin Skull, Generalized<br>Miral D. Jhaveri, MD, MBA<br>28 Thin Skull, Localized<br>Miral D. Jhaveri, MD, MBA<br>30 Lytic Skull Lesion, Solitary<br>Miral D. Jhaveri, MD, MBA<br>34 Multiple Lucent Skull Lesions<br>Miral D. Jhaveri, MD, MBA<br>38 Sclerotic Skull Lesion, Solitary<br>Miral D. Jhaveri, MD, MBA<br>42 Sclerotic Skull Lesions, Multiple<br>Miral D. Jhaveri, MD, MBA<br><br>CLINICALLY BASED DIFFERENTIALS<br>44 Macrocrania/Macrocephaly<br>Luke L. Linscott, MD<br>50 Microcephaly<br>Luke L. Linscott, MD<br><br>MENINGES<br>ANATOMICALLY BASED DIFFERENTIALS<br>56 Dural Calcification(s)<br>Miral D. Jhaveri, MD, MBA<br>58 Dural-Based Mass, Solitary<br>Miral D. Jhaveri, MD, MBA<br>62 Dural-Based Masses, Multiple<br>Miral D. Jhaveri, MD, MBA<br>66 Falx Lesions<br>Miral D. Jhaveri, MD, MBA<br><br>GENERIC IMAGING PATTERNS<br>68 Thick Dura/Arachnoid, Generalized<br>Miral D. Jhaveri, MD, MBA and Yoshimi Anzai, MD, MPH<br>70 Pial Enhancement<br>Miral D. Jhaveri, MD, MBA and Yoshimi Anzai, MD, MPH<br>74 Dural Tail Sign<br>Miral D. Jhaveri, MD, MBA<br><br>VENTRICLES, PERIVENTRICULAR REGIONS<br>ANATOMICALLY BASED DIFFERENTIALS<br>76 Ventricles, Normal Variants<br>Bernadette L. Koch, MD and Chang Yueh Ho, MD<br>80 Choroid Plexus Lesions, Child<br>Chang Yueh Ho, MD and Karen L. Salzman, MD<br>82 Choroid Plexus Lesions, Adult<br>Kalen Riley, MD, MBA, Chang Yueh Ho, MD, and Karen L. Salzman, MD<br>84 Ependymal/Subependymal Lesions<br>Miral D. Jhaveri, MD, MBA<br>90 Lateral Ventricle Mass<br>Karen L. Salzman, MD<br>94 Thick Septum Pellucidum<br>Blair A. Winegar, MD and Karen L. Salzman, MD<br>96 Foramen of Monro Mass<br>Troy A. Hutchins, MD<br>100 3rd Ventricle Mass, Anterior<br>Karen L. Salzman, MD<br>104 3rd Ventricle Mass, Body/Posterior<br>Karen L. Salzman, MD<br>106 Cerebral Aqueduct/Periaqueductal Lesion<br>Nancy J. Fischbein, MD<br>112 4th Ventricle Mass, Child<br>Chang Yueh Ho, MD and Karen L. Salzman, MD<br>116 4th Ventricle Mass, Adult<br>Karen L. Salzman, MD<br><br>GENERIC IMAGING PATTERNS<br>118 Bubbly-Appearing Intraventricular Mass<br>Chang Yueh Ho, MD and Karen L. Salzman, MD<br>122 Ependymal Enhancement<br>Blair A. Winegar, MD and Miral D. Jhaveri, MD, MBA<br>126 Ventriculomegaly<br>Luke L. Linscott, MD<br>132 Small Ventricles<br>Bernadette L. Koch, MD and Chang Yueh Ho, MD<br>134 Asymmetric Lateral Ventricles<br>Santhosh Gaddikeri, MD and Marinos Kontzialis, MD<br>138 Irregular Lateral Ventricles<br>Santhosh Gaddikeri, MD and Marinos Kontzialis, MD<br>142 Periventricular Enhancing Lesions<br>Santhosh Gaddikeri, MD and Marinos Kontzialis, MD<br><br>MODALITY-SPECIFIC IMAGING FINDINGS<br>146 Intraventricular Calcification(s)<br>Blair A. Winegar, MD and Karen L. Salzman, MD<br>150 Periventricular Calcification(s)<br>Luke L. Linscott, MD, Chang Yueh Ho, MD, and Susan I. Blaser, MD, FRCPC<br>154 Periventricular T2-/FLAIR-Hyperintense Lesions<br>Troy A. Hutchins, MD and Karen L. Salzman, MD<br><br>EXTRAAXIAL SPACES AND SUBARACHNOID CISTERNS<br>ANATOMICALLY BASED DIFFERENTIALS<br>158 Subarachnoid Space Normal Variants<br>Luke L. Linscott, MD and Karen L. Salzman, MD<br>160 Epidural Mass<br>Miral D. Jhaveri, MD, MBA and Sheri L. Harder, MD, FRCPC<br>164 Enlarged Sulci, Generalized<br>Troy A. Hutchins, MD and Chang Yueh Ho, MD<br>168 Effaced Sulci, Generalized<br>Troy A. Hutchins, MD and Anne G. Osborn, MD, FACR<br>172 Interhemispheric Fissure Cysts<br>Bernadette L. Koch, MD, Chang Yueh Ho, MD, and Anne G. Osborn, MD, FACR<br>176 CPA Mass, Adult<br>Blair A. Winegar, MD and Karen L. Salzman, MD<br>180 Cystic CPA Mass<br>Karen L. Salzman, MD and H. Ric Harnsberger, MD<br>184 Prepontine Cistern Mass<br>Kalen Riley, MD, MBA, Gregory L. Katzman, MD, MBA, and Miral D. Jhaveri, MD, MBA<br>190 Ventral Foramen Magnum Mass<br>Miral D. Jhaveri, MD, MBA and Karen L. Salzman, MD<br>194 Dorsal Foramen Magnum Mass<br>Miral D. Jhaveri, MD, MBA and Karen L. Salzman, MD<br><br>GENERIC IMAGING PATTERNS<br>198 Solitary Enhancing Cranial Nerve<br>Miral D. Jhaveri, MD, MBA and Anne G. Osborn, MD, FACR<br>200 Multiple Enhancing Cranial Nerves<br>Miral D. Jhaveri, MD, MBA and Anne G. Osborn, MD, FACR<br>204 CSF-Like Extraaxial Fluid Collection<br>Miral D. Jhaveri, MD, MBA and Yoshimi Anzai, MD, MPH<br>206 Convexal Subarachnoid Hemorrhage<br>Miral D. Jhaveri, MD, MBA<br>210 CSF-Like Extraaxial Mass<br>Miral D. Jhaveri, MD, MBA and Yoshimi Anzai, MD, MPH<br>212 Sulcal/Cisternal Enhancement<br>Miral D. Jhaveri, MD, MBA and Sheri L. Harder, MD, FRCPC<br>216 Fat in Sulci/Cisterns/Ventricles<br>Miral D. Jhaveri, MD, MBA and Yoshimi Anzai, MD, MPH<br>218 Pneumocephalus<br>Miral D. Jhaveri, MD, MBA<br><br>MODALITY-SPECIFIC IMAGING FINDINGS<br>220 Extraaxial Flow Voids<br>Santhosh Gaddikeri, MD and Marinos Kontzialis, MD<br>222 T1-Hyperintense CSF<br>Miral D. Jhaveri, MD, MBA and Bronwyn E. Hamilton, MD<br>224 FLAIR-Hyperintense Sulci<br>Miral D. Jhaveri, MD, MBA and Bronwyn E. Hamilton, MD<br>228 T2-Hypointense Extraaxial Lesions<br>Miral D. Jhaveri, MD, MBA and Bronwyn E. Hamilton, MD<br>232 Hyperdense CSF<br>Santhosh Gaddikeri, MD and Marinos Kontzialis, MD<br>234 Hyperdense Extraaxial Mass(es)<br>Miral D. Jhaveri, MD, MBA<br>236 Hypodense Extraaxial Mass(es)<br>Miral D. Jhaveri, MD, MBA and Bronwyn E. Hamilton, MD<br><br>BRAIN PARENCHYMA, GENERAL GENERIC IMAGING PATTERNS<br>240 Multiple Enhancing Lesions, General<br>Karen L. Salzman, MD and Miral D. Jhaveri, MD, MBA<br>244 Ring-Enhancing Lesion, Solitary<br>Miral D. Jhaveri, MD, MBA and Yoshimi Anzai, MD, MPH<br>250 Ring-Enhancing Lesion, Multiple<br>Miral D. Jhaveri, MD, MBA and Yoshimi Anzai, MD, MPH<br>254 Solitary Cystic Parenchymal Mass, General<br>Nancy J. Fischbein, MD and Anne G. Osborn, MD, FACR<br>260 CSF-Like Parenchymal Lesion(s)<br>Troy A. Hutchins, MD and Anne G. Osborn, MD, FACR<br>266 Cyst With Nodule<br>Troy A. Hutchins, MD and Karen L. Salzman, MD<br>270 Fat and Fat-Like Lesion(s)<br>Miral D. Jhaveri, MD, MBA and Sheri L. Harder, MD, FRCPC<br><br>MODALITY-SPECIFIC IMAGING FINDINGS<br>272 Solitary Parenchymal Calcification<br>Miral D. Jhaveri, MD, MBA<br>276 Multiple Parenchymal Calcifications<br>Blair A. Winegar, MD, Anne G. Osborn, MD, FACR, and Miral D. Jhaveri, MD, MBA<br>280 Solitary Hyperdense Parenchymal Lesion<br>Miral D. Jhaveri, MD, MBA and Anne G. Osborn, MD, FACR<br>286 Multiple Hyperdense Parenchymal Lesions<br>Troy A. Hutchins, MD, Anne G. Osborn, MD, FACR, and Miral D. Jhaveri, MD, MBA<br>292 Solitary Hypodense Parenchymal Lesion<br>Miral D. Jhaveri, MD, MBA and Anne G. Osborn, MD, FACR<br>296 Multiple Hypodense Parenchymal Lesions<br>Troy A. Hutchins, MD and Chang Yueh Ho, MD<br>300 Multiple Brain Hyperintensities (T2/FLAIR), Common<br>Santhosh Gaddikeri, MD and Marinos Kontzialis, MD<br>306 Multiple Brain Hyperintensities (T2/FLAIR), Less Common<br>Santhosh Gaddikeri, MD and Marinos Kontzialis, MD<br>312 Multiple Brain Hyperintensities (T2/FLAIR), Rare but Important<br>Santhosh Gaddikeri, MD and Marinos Kontzialis, MD<br>318 Multiple Hypointense Foci on T2<br>Nancy J. Fischbein, MD<br>320 Multiple Hypointense Foci on GRE/SWI<br>Nancy J. Fischbein, MD<br>324 T1-/T2-Hyperintense Parenchymal Lesions<br>Santhosh Gaddikeri, MD and Anne G. Osborn, MD, FACR<br>328 T1-Hypointense, T2-Hyperintense Parenchymal Lesions<br>Santhosh Gaddikeri, MD and Marinos Kontzialis, MD<br>332 T1-/T2-Isointense Parenchymal Lesions<br>Santhosh Gaddikeri, MD and Marinos Kontzialis, MD<br>336 Restricted Diffusion, General<br>Miral D. Jhaveri, MD, MBA and Bronwyn E. Hamilton, MD<br>342 Restricted Diffusion, Cortex<br>Miral D. Jhaveri, MD, MBA<br>344 Restricted Diffusion, Basal Ganglia<br>Miral D. Jhaveri, MD, MBA<br>348 T1-Hyperintense Parenchymal Lesion(s)<br>Santhosh Gaddikeri, MD and Anne G. Osborn, MD, FACR<br><br>CLINICALLY BASED DIFFERENTIALS<br>352 Brain Tumor in Newborn/Infant<br>Chang Yueh Ho, MD<br>358 Brain Tumor in Child > 1 Year<br>Chang Yueh Ho, MD<br>364 Epilepsy, Child<br>Luke L. Linscott, MD<br>370 Epilepsy, Adult<br>Chang Yueh Ho, MD and Bronwyn E. Hamilton, MD<br><br>SUPRATENTORIAL BRAIN PARENCHYMA<br>ANATOMICALLY BASED DIFFERENTIALS<br>372 Asymmetric Cerebral Hemispheres<br>Santhosh Gaddikeri, MD and Gregory L. Katzman, MD, MBA<br>378 Thick Cerebral Cortex<br>Luke L. Linscott, MD<br>384 Thin Cortex<br>Karen L. Salzman, MD, Anne G. Osborn, MD, FACR, and Chang Yueh Ho, MD<br>390 Focal Cortical Mass<br>Chang Yueh Ho, MD and James D. Eastwood, MD<br>396 Cortical Hyperintensity T2/FLAIR<br>Karen L. Salzman, MD<br>400 Cortical Enhancement<br>Karen L. Salzman, MD<br>402 Solitary White Matter Lesion<br>Santhosh Gaddikeri, MD and Marinos Kontzialis, MD<br>406 Confluent White Matter Lesions<br>Karen L. Salzman, MD<br>412 Abnormal Shape/Configuration of Corpus Callosum<br>Luke L. Linscott, MD<br>418 Corpus Callosum Holes<br>Troy A. Hutchins, MD and Karen L. Salzman, MD<br>420 Corpus Callosum Lesion Without Mass Effect<br>Karen L. Salzman, MD<br>422 Corpus Callosum Mass<br>Karen L. Salzman, MD<br>424 Corpus Callosum Splenium Lesion<br>Troy A. Hutchins, MD<br>428 Medial Temporal Lobe Lesion<br>Chang Yueh Ho, MD<br>434 Hippocampal Lesion<br>Chang Yueh Ho, MD<br>438 Basal Ganglia Calcification<br>Karen L. Salzman, MD<br>442 Hyperdense Basal Ganglia<br>Karen L. Salzman, MD<br>444 Hypodense Basal Ganglia<br>Karen L. Salzman, MD<br>448 T1-Hyperintense Basal Ganglia<br>Karen L. Salzman, MD<br>452 T2-Hyperintense Basal Ganglia<br>Karen L. Salzman, MD<br>456 Enlarged Perivascular Spaces<br>Karen L. Salzman, MD<br>458 Perivascular Space Enhancing Lesions<br>Karen L. Salzman, MD<br>462 Bilateral Basal Ganglia Lesions<br>Nancy J. Fischbein, MD<br>466 Putamen Lesion(s)<br>Karen L. Salzman, MD<br>468 Globus Pallidus Lesion(s)<br>Karen L. Salzman, MD<br>472 Unilateral Thalamic Lesion<br>Karen L. Salzman, MD<br>474 Bithalamic Lesions<br>Nancy J. Fischbein, MD and Karen L. Salzman, MD<br>478 Pulvinar Sign<br>Karen L. Salzman, MD<br>480 Tectal (Quadrigeminal Plate) Lesion<br>Karen L. Salzman, MD<br><br>INFRATENTORIAL BRAIN PARENCHYMA<br>ANATOMICALLY BASED DIFFERENTIALS<br>482 Large Brainstem<br>Karen L. Salzman, MD<br>484 Small Brainstem<br>Karen L. Salzman, MD<br>486 T2-Hyperintense Brainstem, Focal<br>Karen L. Salzman, MD<br>488 T2-Hyperintense Brainstem, Diffuse<br>Karen L. Salzman, MD<br>490 Midbrain Lesion<br>Nancy J. Fischbein, MD<br>494 Pontine Lesion<br>Nancy J. Fischbein, MD<br>500 Medulla Lesion<br>Nancy J. Fischbein, MD<br>504 Middle Cerebellar Peduncle Lesion(s)<br>Nancy J. Fischbein, MD<br>508 Cerebellar Atrophy<br>Anne G. Osborn, MD, FACR and Chang Yueh Ho, MD<br>512 Cerebellar Hemisphere Mass<br>Chang Yueh Ho, MD<br>518 Vermis Mass<br>Chang Yueh Ho, MD<br>522 Low Cerebellar Tonsils<br>Luke L. Linscott, MD<br> <br>GENERIC IMAGING PATTERNS<br>524 Cystic-Appearing Posterior Fossa Lesion<br>Luke L. Linscott, MD<br><br>CLINICALLY BASED DIFFERENTIALS<br>530 Posterior Fossa Neoplasm, Adult<br>Tabassum A. Kennedy, MD and Anne G. Osborn, MD, FACR<br>534 Posterior Fossa Neoplasm, Pediatric<br>Chang Yueh Ho, MD<br><br>SELLA/JUXTASELLAR, PINEAL REGION<br>ANATOMICALLY BASED DIFFERENTIALS<br>540 Pineal Region Mass, General<br>Chang Yueh Ho, MD and Gregory L. Katzman, MD, MBA<br>544 Pineal Gland Mass<br>Chang Yueh Ho, MD and Karen L. Salzman, MD<br>546 Quadrigeminal Cistern Mass<br>Chang Yueh Ho, MD<br>548 Pineal + Suprasellar Lesions<br>Karen L. Salzman, MD<br>550 Sella/Pituitary Normal Variants<br>Kalen Riley, MD, MBA, Anne G. Osborn, MD, FACR, and Karen L. Salzman, MD<br>552 Sellar/Juxtasellar Calcification<br>Blair A. Winegar, MD and Anne G. Osborn, MD, FACR<br>556 Enlarged Pituitary Gland<br>Karen L. Salzman, MD and Anne G. Osborn, MD, FACR<br>558 Intrasellar Lesion<br>Blair A. Winegar, MD, Karen L. Salzman, MD, and Anne G. Osborn, MD, FACR<br>560 Cystic Intrasellar Mass<br>Karen L. Salzman, MD and Anne G. Osborn, MD, FACR<br>562 Suprasellar Mass, Child<br>Chang Yueh Ho, MD and Anne G. Osborn, MD, FACR<br>568 Suprasellar Mass, Adult<br>Karen L. Salzman, MD<br>572 Suprasellar Cystic Mass<br>Tabassum A. Kennedy, MD, Anne G. Osborn, MD, FACR, and Karen L. Salzman, MD<br>576 Calcified Suprasellar Mass<br>Blair A. Winegar, MD, Anne G. Osborn, MD, FACR, and Karen L. Salzman, MD<br>578 Enhancing Suprasellar Mass<br>Kalen Riley, MD, MBA, Anne G. Osborn, MD, FACR, and Karen L. Salzman, MD<br>580 Sellar/Parasellar Mass With Skull Base Invasion<br>Blair A. Winegar, MD and Anne G. Osborn, MD, FACR<br>584 Absent/Thin Infundibular Stalk<br>Bernadette L. Koch, MD, Chang Yueh Ho, MD, and Anne G. Osborn, MD, FACR<br>586 Thick Infundibular Stalk<br>Kalen Riley, MD, MBA, Chang Yueh Ho, MD, and Anne G. Osborn, MD, FACR<br>588 Hypothalamus Lesion<br>Kalen Riley, MD, MBA, Chang Yueh Ho, MD, and Anne G. Osborn, MD, FACR<br><br>MODALITY-SPECIFIC IMAGING FINDINGS<br>592 Hyperdense Suprasellar Mass<br>Kalen Riley, MD, MBA, Anne G. Osborn, MD, FACR, and Karen L. Salzman, MD<br>594 T1-Hyperintense Suprasellar Mass<br>Karen L. Salzman, MD and Anne G. Osborn, MD, FACR<br><br>ARTERIES<br>ANATOMICALLY BASED DIFFERENTIALS<br>596 Multifocal Arterial Narrowing<br>Hediyeh Baradaran, MD, MS and J. Scott McNally, MD, PhD<br>600 Vessel Wall Abnormalities<br>Hediyeh Baradaran, MD, MS and J. Scott McNally, MD, PhD<br>604 Fusiform Arterial Enlargement<br>Hediyeh Baradaran, MD, MS and Chang Yueh Ho, MD<br><br>MODALITY-SPECIFIC IMAGING FINDINGS<br>606 Hyperattenuating ("Dense") Artery<br>Hediyeh Baradaran, MD, MS, Sheri L. Harder, MD, FRCPC, and Karen L. Salzman, MD<br><br>VEINS, VENOUS SINUSES<br>ANATOMICALLY BASED DIFFERENTIALS<br>08 Dural Sinus Lesion, General<br>lair A. Winegar, MD and Karen L. Salzman, MD<br>612 Enlarged Cortical Veins<br>Blair A. Winegar, MD and Karen L. Salzman, MD<br>614 Prominent/Enlarged Deep (Medullary/Ependymal) Veins<br>Karen L. Salzman, MD and James D. Eastwood, MD<br>618 Abnormally Enhancing Medullary Veins<br>Hediyeh Baradaran, MD, MS<br>620 Unilateral Cavernous Sinus Mass<br>Santhosh Gaddikeri, MD, Marinos Kontzialis, MD, and Anne G. Osborn, MD, FACR<br>624 Bilateral Cavernous Sinus Lesions<br>Blair A. Winegar, MD, Karen L. Salzman, MD, and Anne G. Osborn, MD, FACR<br>628 Meckel Cave Lesion<br>Kalen Riley, MD, MBA, Anne G. Osborn, MD, FACR, and Karen L. Salzman, MD<br><br>MODALITY-SPECIFIC IMAGING FINDINGS<br>632 Hyperdense Dural Sinus<br>Kalen Riley, MD, MBA, Anne G. Osborn, MD, FACR, and Karen L. Salzman, MD<br>636 GRE/SWI Venous Abnormalities<br>Kalen Riley, MD, MBA and Miriam E. Peckham, MD<br><br>CRANIAL NERVES<br>CLINICALLY BASED DIFFERENTIALS<br>638 Hemifacial Spasm<br>Nicholas A. Koontz, MD<br>642 Sensorineural Hearing Loss in Adult<br>Nicholas A. Koontz, MD and H. Ric Harnsberger, MD<br>646 Sensorineural Hearing Loss in Child<br>Bernadette L. Koch, MD<br>652 Bitemporal Heteronymous Hemianopsia<br>Blair A. Winegar, MD and Kristine M. Mosier, DMD, PhD<br>658 Homonymous Hemianopsia<br>Tabassum A. Kennedy, MD<br>662 Oculomotor, Trochlear, or Abducens Neuropathy<br>Nicholas A. Koontz, MD<br>668 Trigeminal Neuralgia<br>Nicholas A. Koontz, MD<br>672 Complex Cranial Nerve IX-XII Neuropathy<br>Nicholas A. Koontz, MD<br>678 Horner Syndrome<br>Nicholas A. Koontz, MD<br><br>SECTION 2: SPINE<br>TRANSSPATIAL<br>ANATOMICALLY BASED DIFFERENTIALS<br>686 Cervical, Chronic Posttraumatic Abnormality<br>Jeffrey S. Ross, MD<br>688 Cervical, Lower, Posttraumatic Bony Abnormality<br>Jeffrey S. Ross, MD and Julia R. Crim, MD<br>690 Thoracic Bony Trauma<br>Jeffrey S. Ross, MD and Julia R. Crim, MD<br>692 Lumbar Bony Trauma<br>Jeffrey S. Ross, MD and Julia R. Crim, MD<br>GENERIC IMAGING PATTERNS<br>694 Kyphosis<br>Jeffrey S. Ross, MD, Julia R. Crim, MD, and Kevin R. Moore, MD<br>696 Kyphoscoliosis, Child<br>Jeffrey S. Ross, MD, Julia R. Crim, MD, and Kevin R. Moore, MD<br>698 Platyspondyly, Diffuse<br>Jeffrey S. Ross, MD, Julia R. Crim, MD, and Kevin R. Moore, MD<br>700 Sacral Mass, Adult<br>Jeffrey S. Ross, MD<br>704 Sacrococcygeal Mass, Pediatric<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>708 Sacral Deformity<br>Jeffrey S. Ross, MD, Bryson Borg, MD, and Kevin R. Moore, MD<br>712 Multicompartmental Mass<br>Jeffrey S. Ross, MD<br><br>CLINICALLY BASED DIFFERENTIALS<br>718 Acute Back Pain/Radiculopathy, Postoperative<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>724 Chronic Back Pain/Radiculopathy, Postoperative<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>730 Acute Upper Extremity Pain/Weakness<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>736 Lower Extremity Pain<br>Jeffrey S. Ross, MD and Bryson Borg, MD<br>740 Back Pain, Adult<br>Jeffrey S. Ross, MD and Bryson Borg, MD<br>746 Back Pain, Pediatric<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br><br>CRANIOVERTEBRAL JUNCTION<br>ANATOMICALLY BASED DIFFERENTIALS<br>750 Craniocervical Junction Acute Injury<br>Jeffrey S. Ross, MD and Julia R. Crim, MD<br>754 Craniovertebral Junction Abnormality, General<br>Jeffrey S. Ross, MD and Julia R. Crim, MD<br>758 Craniovertebral Junction Soft Tissue Abnormality<br>Jeffrey S. Ross, MD<br><br>GENERIC IMAGING PATTERNS<br>762 C1-C2 Instability<br>Jeffrey S. Ross, MD<br>766 Odontoid Deformity<br>Jeffrey S. Ross, MD and Julia R. Crim, MD<br><br>VERTEBRAL BODY, POSTERIOR ELEMENTS<br>ANATOMICALLY BASED DIFFERENTIALS<br>768 Congenital Vertebral Anomalies<br>Jeffrey S. Ross, MD and Julia R. Crim, MD<br>770 Cervical Bony Fusion<br>Jeffrey S. Ross, MD, Julia R. Crim, MD, and Kevin R. Moore, MD<br><br>GENERIC IMAGING PATTERNS<br>772 Flattened Vertebral Body, Solitary<br>Jeffrey S. Ross, MD and Julia R. Crim, MD<br>774 Flattened Vertebral Body, Multiple<br>Jeffrey S. Ross, MD, Julia R. Crim, MD, and Kevin R. Moore, MD<br>776 Dysmorphic Vertebral Body<br>Jeffrey S. Ross, MD, Kevin R. Moore, MD, and Julia R. Crim, MD<br>778 Enlarged Vertebral Body/Posterior Element<br>Jeffrey S. Ross, MD<br>782 Enlarged Neural Foramen<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>784 Vertebral Body Scalloping/Widened Canal<br>Jeffrey S. Ross, MD and Bryson Borg, MD<br>786 Spondylolisthesis<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>790 Bony Lesion, Aggressive<br>Jeffrey S. Ross, MD and Lubdha M. Shah, MD<br>794 Fracture, Vertebral Body<br>Jeffrey S. Ross, MD, Julia R. Crim, MD, and Kevin R. Moore, MD<br>798 Facet Abnormality, Nontraumatic<br>Jeffrey S. Ross, MD and Lubdha M. Shah, MD<br>800 Fracture, Posterior Element<br>Jeffrey S. Ross, MD, Julia R. Crim, MD, and Kevin R. Moore, MD<br>802 Pedicle Abnormality<br>Jeffrey S. Ross, MD<br><br>MODALITY-SPECIFIC IMAGING FINDINGS<br>806 Enlarged Vertebral Body, Soap Bubble Expansion<br>Jeffrey S. Ross, MD and Lubdha M. Shah, MD<br>810 Vertebral Body Sclerosis, Focal<br>Jeffrey S. Ross, MD<br>814 Vertebral Body Sclerosis, Diffuse<br>Jeffrey S. Ross, MD and Bryson Borg, MD<br>816 Vertebral Body Thickened Bony Trabeculae<br>Jeffrey S. Ross, MD and Lubdha M. Shah, MD<br>818 Vertebral Body, T1-Hyperintense Signal, Diffuse<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>820 Vertebral Body, T1-Hyperintense Signal, Focal<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>822 Vertebral Body, T1-Hypointense Signal, Diffuse<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>826 Vertebral Body, T1-Hypointense Signal, Focal<br>Jeffrey S. Ross, MD and Bryson Borg, MD<br><br>INTERVERTEBRAL DISC, ENDPLATE<br>GENERIC IMAGING PATTERNS<br>828 Disc Contour Abnormality<br>Jeffrey S. Ross, MD<br>832 Intervertebral Disc/Endplate Irregularity<br>Jeffrey S. Ross, MD<br>836 Vertebral Endplate Contour Abnormality<br>Jeffrey S. Ross, MD and Julia R. Crim, MD<br><br>MODALITY-SPECIFIC IMAGING FINDINGS<br>840 Intervertebral Disc, T1 Hypointense<br>Jeffrey S. Ross, MD<br>842 Intervertebral Disc, T2 Hyperintense<br>Jeffrey S. Ross, MD<br>844 Vertebral Endplate Signal Abnormality<br>Jeffrey S. Ross, MD<br><br>EXTRADURAL<br>ANATOMICALLY BASED DIFFERENTIALS<br>846 Epidural Mass<br>Jeffrey S. Ross, MD and Bryson Borg, MD<br>852 Ventral/Lateral Paraspinal Mass<br>Jeffrey S. Ross, MD<br><br>GENERIC IMAGING PATTERNS<br>854 Paraspinal Muscle Abnormality<br>Jeffrey S. Ross, MD<br>856 Extradural Lesions, Multiple<br>Jeffrey S. Ross, MD and Bryson Borg, MD<br>858 Extradural Lesion, No Enhancement<br>Jeffrey S. Ross, MD<br>860 Extradural Lesion, Solid Enhancement<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>864 Epidural Fluid<br>Jeffrey S. Ross, MD <br><br>MODALITY-SPECIFIC IMAGING FINDINGS<br>868 Soft Tissue Calcification, Paraspinal<br>Jeffrey S. Ross, MD<br>870 Extradural, Normal Marrow Signal<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>874 Extradural, Abnormal Marrow Signal<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>878 Extradural Lesion, T1 Hyperintense<br>Jeffrey S. Ross, MD, Bryson Borg, MD, and Kevin R. Moore, MD<br>880 Extradural Lesion, T1 Hypointense<br>Jeffrey S. Ross, MD, Bryson Borg, MD, and Kevin R. Moore, MD<br>884 Extradural Lesion, T2 Hyperintense, T1 Isointense<br>Jeffrey S. Ross, MD<br>888 Extradural Lesion, T2 Hypointense, T1 Hypointense<br>Jeffrey S. Ross, MD, Bryson Borg, MD, and Kevin R. Moore, MD<br><br>CLINICALLY BASED DIFFERENTIALS<br>890 Lumbar Soft Tissue Mass, Pediatric<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br><br>INTRADURAL EXTRAMEDULLARY<br>ANATOMICALLY BASED DIFFERENTIALS<br>894 Cauda Equina Enhancement, Diffuse<br>Jeffrey S. Ross, MD<br>898 Subarachnoid Space Narrowing<br>Jeffrey S. Ross, MD and Bryson Borg, MD<br>900 Intradural Extramedullary, Leptomeningeal Enhancement<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br><br>GENERIC IMAGING PATTERNS<br>904 Intradural Extramedullary Lesion, No Enhancement<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>908 Intradural Extramedullary Lesion, Solid Enhancement<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>912 Intradural Lesion, Serpentine<br>Jeffrey S. Ross, MD<br>914 Intradural Extramedullary Lesion, Multiple<br>Jeffrey S. Ross, MD and Bryson Borg, MD<br><br>MODALITY-SPECIFIC IMAGING FINDINGS<br>918 Intradural Extramedullary Lesion, Ring/Peripheral Enhancement<br>Jeffrey S. Ross, MD<br>922 Intradural Extramedullary Lesion, T1 Hyperintense<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>924 Intradural Extramedullary Lesion, T1 Hypointense<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>928 Intradural Extramedullary Lesion, T1 Hypointense, T2 Hypointense<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>930 Intradural Extramedullary Lesion, T2 Hyperintense, T1 Isointense<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br><br>CLINICALLY BASED DIFFERENTIALS<br>932 Cauda Equina Syndrome<br>Jeffrey S. Ross, MD and Bryson Borg, MD<br><br>INTRAMEDULLARY<br>ANATOMICALLY BASED DIFFERENTIALS<br>934 Intramedullary Mass<br>Jeffrey S. Ross, MD and Bryson Borg, MD<br>938 Conus Abnormality<br>Jeffrey S. Ross, MD and Bryson Borg, MD<br>GENERIC IMAGING PATTERNS<br>942 Intramedullary Lesions, Multiple<br>Jeffrey S. Ross, MD, Lubdha M. Shah, MD, and Kevin R. Moore, MD<br>944 Intramedullary Lesion, Solid Enhancement=<br>Jeffrey S. Ross, MD, Lubdha M. Shah, MD, and Kevin R. Moore, MD<br>948 Intramedullary Lesion, No Enhancement<br>Jeffrey S. Ross, MD, Lubdha M. Shah, MD, and Kevin R. Moore, MD<br>950 Intramedullary Lesion, Diffuse/Ill-Defined Enhancement<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD<br>954 Intramedullary Lesion, Ring/Peripheral Enhancement<br>Jeffrey S. Ross, MD, Lubdha M. Shah, MD, and Kevin R. Moore, MD<br><br>MODALITY-SPECIFIC IMAGING FINDINGS<br>956 Intramedullary Lesion, T1 Hypointense, T2 Hypointense<br>Jeffrey S. Ross, MD, Lubdha M. Shah, MD, and Kevin R. Moore, MD<br>958 Intramedullary Lesion, T1 Hypointense<br>Jeffrey S. Ross, MD and Lubdha M. Shah, MD<br>960 Intramedullary Lesion, T2 Hyperintense, T1 Isointense<br>Jeffrey S. Ross, MD and Lubdha M. Shah, MD<br>964 Intramedullary Lesion, T1 Hyperintense<br>Jeffrey S. Ross, MD and Lubdha M. Shah, MD<br>970 Cord Lesion, T2 Hyperintense, Ventral<br>Jeffrey S. Ross, MD and Lubdha M. Shah, MD<br>972 Cord Lesion, T2 Hyperintense, Dorsal<br>Jeffrey S. Ross, MD<br>976 Cord Lesion, T2 Hyperintense, Central<br>Jeffrey S. Ross, MD and Lubdha M. Shah, MD<br><br>CLINICALLY BASED DIFFERENTIALS<br>982 Myelopathy<br>Jeffrey S. Ross, MD and Kevin R. Moore, MD