Table Of ContentAtlas of Head/Neck
and Spine Normal Imaging
VVVaaarrriiiaaannntttsss
Alexander McKinney · Zuzan Cayci
Mehmet Gencturk · David Nascene
Matt Rischall · Jeff rey Rykken
Frederick Ott
123
Atlas of Head/Neck and Spine Normal
Imaging Variants
Alexander McKinney • Zuzan Cayci
Mehmet Gencturk • David Nascene
Matt Rischall • Jeffrey Rykken
Frederick Ott
Atlas of Head/Neck and Spine
Normal Imaging Variants
Alexander McKinney, MD, CI/CIIP Zuzan Cayci, MD
Department of Radiology Department of Radiology
University of Minnesota University of Minnesota
Minneapolis, MN, USA Minneapolis, MN, USA
Mehmet Gencturk, MD David Nascene, MD
Department of Radiology Department of Radiology
University of Minnesota University of Minnesota
Minneapolis, MN, USA Minneapolis, MN, USA
Matt Rischall, MD Jeffrey Rykken, MD
Department of Radiology Department of Radiology
University of Minnesota University of Minnesota
Minneapolis, MN, USA Minneapolis, MN, USA
Frederick Ott, MD
Department of Radiology
University of Minnesota
Minneapolis, MN, USA
ISBN 978-3-319-95440-0 ISBN 978-3-319-95441-7 (eBook)
https://doi.org/10.1007/978-3-319-95441-7
Library of Congress Control Number: 2018957084
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Alex McKinney: This is dedicated to my nuclear and extended family, who
have been very patient and attempt to keep me balanced, including Jennelle,
Amina, Aliya, Zaki, and Nura. Also, to my parents Alex and Roni, and my
brother Zeke who have helped me focus in more ways than I could imagine.
Fred Ott: This is dedicated to my girlfriend and soulmate Heather who has
encouraged and supported me, more than I have ever been in the past. To my
children Brent, Brittany, and Brooke, my grandson Winston, and son-in-law
Nicholas who have brought me my share of joy. My father Wilbert and my
mother Vivian who passed in 2017. They were always there for me whenever I
needed them and taught me what really counts in life: family. My brother
Robert, sisters Sheila and Connie, Heather’s children James and Sophia. And
of course, I praise and thank God for everything He’s done for me. “I can do
all things through Christ who strengthens me” Philippians 4:13.
Zuzan Cayci: This is dedicated to Cenk, my husband, who has always
supported and encouraged me during any challenge I face, to my children
Lara and Kaya who are the joys of my life, and to my mother, father, and
brother who have always been there whenever I needed them.
Jeff Rykken: This is dedicated to my family, who continue to give me the most
joy in my life. Especially to my lovely wife, Erin, who helps me stay grounded
and achieve the balance that I need. To my kids Jaxson and James, who keep
me young and challenge me in the ways that all good kids do. And certainly
my parents, Janis and Bruce, who have supported and encouraged me
always. Lastly, to the creator of the coffee bean, without which this project
would not have been possible.
Matt Rischall: This work is dedicated to my wife Megan, the inspiration,
sounding board, and backbone for so many things in my life. I thank my
children Rosemary and Maeve for giving me more love and more to love than
I ever thought possible. I am forever indebted to my parents Daniel and
Karen for providing me with endless patience and compassion, for being my
role models for life, and especially for availing themselves for all of the
babysitting of late. To my brother Andrew, your humor and company continue
to provide me with great joy.
Mehmet Gencturk: This is dedicated to my wife Nurhan, who has always
supported me during my education in the USA, and to my daughter Su Ada,
who came into our lives a year ago and brought joy, happiness, and energy.
David Nascene: My work in this book is dedicated to my family, including my
wife Shannon, who has been through it all with me; my kids Laurel, Sophie,
and Ben, who keep life interesting and make it all worthwhile; and my
parents, Kevin and LeeAnn, who started me on my path. I would also like to
thank all of my teachers along the way, each of whom has placed their mark
on me, who collectively have made me into the educator that I am proud to be
(especially my most important teacher, my mother).
We mutually dedicate this to our past, current, and future residents, fellows,
medical students, and research assistants who we have learned from as much
as they have learned from us. Without an academic environment and
individuals who are eager to learn, we would lose the initiative to improve.
Finally we dedicate this to Bibi Husain, our administrator, who shows more
patience than all of us combined and helps to keeps us as a hardworking and
cohesive group!
Preface
In my previous atlas, Atlas of Normal Imaging Variations of the Brain, Skull, and Craniocervical
Vasculature, released a year before this atlas, I opined “art can be work” and “work can be art.”
I developed this adage, but it is certainly predicated on how much someone is both committed
to, while simultaneously deriving enjoyment from, their profession. I can say with certainty
that both myself and the other six authors of this book feel this way about the field of neurora-
diology. This is why we opted for a rather experimental and uncommon “multiauthor” approach
to this book; we felt as a neuroradiology division that if we each shouldered a section of the
book, we could complete the first edition in a much shorter time than my previous book, which
took more than 10 years to compile. I therefore salute each of my coauthors, who are also my
work colleagues. As their Division Director, I have been honored and fortunate to work with a
group of my peers who both have mutual respect for each other and feel open to approach each
other with suggestions and peer review for both clinical care and research. Below I summarize
our approach to the six subsections/chapters of the book, which very much parallels the
approach in my prior book and which our readership audience is focused on.
As with the abovementioned reason that this might be akin to composing “art” and as with
my former work, this book is not a matter of just finding references for a particular normal vari-
ant. In many ways, it is more difficult than composing a peer-reviewed journal article or review,
which I feel are more straightforward, since there is a limited range of possibilities and defined
subject matter. The subject of normal variations can be difficult to address (as discussed in the
prior book), because (1) a normal or “don’t touch” variant may be either not visualized or not
mentioned as it is of no consequence; (2) a variant is seen but constantly called abnormal but
never proven to be so, as it is not a surgical entity; and (3) in the reverse of #1, the variant is
thought as abnormal, but dedicated imaging is necessary to “put one’s shoulder against the
ocean liner” of physicians wanting to perform unnecessary therapy. Scenario #3 is more clini-
cally important scenario for normal variants, as operating on a potentially normal variant that
was initially suspected to be abnormal may lead to serious iatrogenic complications. Thus,
depicting and confirming a normal variation can be an art form, as it may require using one’s
critical thinking skills and imagination to prove the variant as normal. To prevent situation #3
(and thus expectation bias), trainees and fellows are urged initially, prior to reviewing the clini-
cal history, to first simply “say what they see” about an image (borrowing the words of our
pioneer/predecessor and one of the original founders of the field of Neuroradiology in Minnesota,
Dr. Harold O. Peterson). It seems that what a radiologist or clinician suspects to be a normal
may be just that, but it needs proof. Therefore, the goal of this book is to compile the most com-
mon, identifiable, or interesting variants and to provide facile methods to identify them, as well
as a range of imaging appearances to augment the provider’s ability to identify such normal
variations. Some variants are accompanied by “Comparison Cases,” which cement the appear-
ance of a normal variant in one’s mind to compare/contrast the actual abnormality that the
radiologist is worried about. Hence, such cases are intended to create a “spectrum of normal”
within the radiologist’s mind for comparison with the case they are interpreting.
The intended audience for this text includes radiologists, non-radiologists clinicians, and
care providers, as well as their trainees. This may be a wider audience than in my previous text
that covered predominately the brain, skull, and craniocervical vasculature, as this text covers
vii
viii Preface
a much wider anatomic range that includes the skull base, head/neck, orbits, sinuses, facial
bones, and the entire spine. These other non-radiologist providers include, but are not limited
to, neurologists, neurosurgeons, general surgeons, orthopedic surgeons, radiologic technolo-
gists, and others. We have chosen to reference and describe each particular subject in what we
considered a brief fashion while simultaneously attempting to cover the most important aspects
of each subject. For this purpose, the references are quoted at the end of each section, and we
quote a range of numbers regarding the incidence of a variant rather than the exact percentage.
Otherwise, our attempt to keep such descriptions under the length of 1–2 pages would have
been rendered futile and would have disrupted the intent of the publisher and ourselves to have
“more pictures than text.” We opine that the purpose of the References, which are overall given
in the order that the topic is described, is for more detailed analysis at the reader’s discretion.
Hence, we admit that this book is not intended for as much of an in-depth analysis of each
variant but rather a review for a particular picture or imaging appearance. If mistakes are iden-
tified (which we are confident will occur) or if there are topic suggestions, we are open to an
email to improve this work. Please provide a reference, and upon the release of a future ver-
sion, we intend to acknowledge such a contribution.
Minneapolis, MN, USA Alexander M. McKinney IV, MD, CI-CIIP
Contents
1 Head/Neck and Spine Imaging Variants: Introduction . . . . . . . . . . . . . . . . . . . . . 1
2 Sinonasal Variants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1 Introduction, Technique, and Basic Anatomy . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Pattern of Serial Paranasal Sinus Development and
Sequential Pneumatization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.3 Maxillary Sinus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3.1 Maxillary Sinus Hypoplasia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3.2 Accessory Maxillary Sinus Ostia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3.3 Maxillary Sinus Septa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.3.4 Dehiscence of the Infraorbital Nerve Canal . . . . . . . . . . . . . . . . . . . . . . 16
2.3.5 Maxillary Sinus Teeth (“Ectopic Teeth”) . . . . . . . . . . . . . . . . . . . . . . . . 17
2.4 Sphenoid Sinus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.4.1 Sphenoid Sinus Pneumatization: Aerated-Pneumatized Clinoid
(Onodi Cell), Pterygoid Processes, and Dehiscent Neural Structures . . . . 20
2.4.2 Arrested Pneumatization of the Sphenoid Sinus . . . . . . . . . . . . . . . . . . 29
2.5 Frontal Sinus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
2.5.1 Frontal Sinus Aplasia and Hypoplasia . . . . . . . . . . . . . . . . . . . . . . . . . . 30
2.5.2 Crista Galli Aeration-Pneumatization and Other Forms of
Frontal Sinus Midline Extension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
2.6 Ethmoidal Air Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
2.6.1 Agger Nasi Cell, Haller Cell, Bulla Ethmoidalis, and
Suprabulbar Recess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
2.7 Nasal Cavity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
2.7.1 Concha Bullosa and Pneumatized Uncinate Process . . . . . . . . . . . . . . . 42
2.7.2 Paradoxical Middle Turbinate and Turbinate Sinus . . . . . . . . . . . . . . . . 43
2.7.3 Nasal Septal Deviation, Septal Spur, and Septal Pneumatization . . . . . 45
2.8 Anterior Skull Base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
2.8.1 Lateral Lamellar Dehiscence and Asymmetry
of the Olfactory Fossae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
2.8.2 The Nasal Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Suggested Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
3 Orbital Variants. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
3.1 Introduction, Technique, and Basic Anatomy . . . . . . . . . . . . . . . . . . . . . . . . . . 53
3.2 Bony Orbit: Normal Orbital Sutures, Orbital Roof Thinning, and Orbital
Decompression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
3.2.1 Normal Orbital Sutures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
3.2.2 Orbital Roof Thinning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
3.2.3 Postoperative Orbital Decompression . . . . . . . . . . . . . . . . . . . . . . . . . . 54
3.3 Globe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3.3.1 Intraocular Lens Implant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3.3.2 Glaucoma Shunt Implant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
ix
x Contents
3.3.3 Scleral Buckle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3.3.4 Ocular Injection of Gas or Silicone Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3.3.5 Orbital Implant and Ocular Prosthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
3.3.6 Eyelid Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.3.7 Congenital Proptosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.3.8 Pseudo-proptosis and Measurement Error Caused by Nonuniform Axial Plane . . . . . . . . . . . . . . . . . . 57
3.3.9 Sedation-Related Strabismus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
3.4 Extraocular Muscles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
3.4.1 Normal Contrast Enhancement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
3.4.2 Physiologic FDG Uptake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
3.5 Optic Nerve Tortuosity, Diameter, Sheath Distention, and Normal Perineural Enhancement . . . . . . . . . . . . . 66
3.5.1 Optic Nerve Tortuosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
3.5.2 Optic Nerve Sheath Distention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
3.5.3 Optic Perineural Enhancement: A Normal Variant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
3.5.4 Optic Nerve Diameter and Normal Variation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
3.6 Orbital Calcifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
3.6.1 Trochlear Calcifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
3.6.2 Drusen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
3.6.3 Senile Scleral Plaques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
3.6.4 Arterial Atherosclerosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
3.7 Orbital Venous System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
3.7.1 Superior Ophthalmic Vein Asymmetry and Enlargement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
3.7.2 Inferior Ophthalmic Venous Plexus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
3.7.3 Orbital Venous Varix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
3.8 Lacrimal Gland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
3.8.1 Lacrimal Gland Size, Symmetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
3.8.2 Lacrimal Gland Cyst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
3.9 Nasolacrimal Duct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
3.9.1 Opacification/Aeration and Size/Morphology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
3.10 Orbital Artifacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
3.10.1 Incomplete Fat Suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
3.10.2 Ocular Motion Artifact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
3.10.3 Truncation Artifact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
3.10.4 Metallic Susceptibility Artifact from Adjacent Facial Hardware or Orbital Foreign Body . . . . . . . . . . 84
Suggested Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
4 Neck Soft Tissue Variants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
4.1 Introduction, Technique, and Basic Anatomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
4.2 Tornwaldt Cyst (Pharyngeal Bursa) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
4.3 Adenoidal Retention Cyst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
4.4 Lingual Tonsillar Hypertrophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
4.5 Vallecular Cyst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
4.6 Laryngocele . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
4.7 Parapharyngeal Space Lipoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
4.8 Medial Retropharyngeal Lymph Nodes in Children . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
4.9 Pterygoid Venous Plexus Asymmetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
4.10 Denervation Atrophy of Masticator Muscles and Asymmetric Masticator Uptake on PET-CT . . . . . . . . . . . . 106
4.11 Hypoglossal Denervation and Hemiglossal Atrophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
4.12 Retropharyngeal Carotid Artery (If Bilateral: “Kissing Carotid Arteries”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
4.13 Thyroid Lipoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
4.14 Thyroid Cartilage Lipoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
4.15 Thyroglossal Duct Cyst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
4.16 Ectopic Thyroid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
4.17 Thyroid Isthmus Agenesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
