mri atlas of the abdomen (a self-guided tutorial)

MRI Atlas of the AbdomenMRI Atlas of the Abdomen(a self-guided tutorial)(a self-guided tutorial)

Jeff Velez HMS3Jeff Velez HMS3

Eric Chiang, MD Eric Chiang, MD

Gillian Lieberman, MDGillian Lieberman, MD

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GoalsGoalsThe purpose of this atlas is to provide students with; The purpose of this atlas is to provide students with;

• an outline of the anatomy of the abdomen via MR imaging. an outline of the anatomy of the abdomen via MR imaging.

• an introduction to how an MR image is created.an introduction to how an MR image is created.• a basic understanding of how the manipulation of various a basic understanding of how the manipulation of various

parameters (TR,TE, pulse sequence) of an MR scan yield parameters (TR,TE, pulse sequence) of an MR scan yield desired tissue differentiation.desired tissue differentiation.

• a list of some basic sequences used in abdominal MR.a list of some basic sequences used in abdominal MR.

By coupling this review of how an MR image is created By coupling this review of how an MR image is created and manipulated with a thorough tour of abdominal and manipulated with a thorough tour of abdominal anatomy seen through MRI, this tutorial can serve as an anatomy seen through MRI, this tutorial can serve as an instructive tool in preparing students for their likely instructive tool in preparing students for their likely future clinical encounters with abdominal MRI in future clinical encounters with abdominal MRI in evaluating and managing abdominal disease.evaluating and managing abdominal disease.

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IntroductionIntroduction

Magnetic resonance (MR) imaging has been in widespread clinical Magnetic resonance (MR) imaging has been in widespread clinical use for well over a decade. Its use was primarily localized to the use for well over a decade. Its use was primarily localized to the evaluation of the central nervous system and then more recently, evaluation of the central nervous system and then more recently, the musculoskeletal system. Motion during the cardiac cycle , the musculoskeletal system. Motion during the cardiac cycle , respiration, and peristalsis made MR imaging of the thorax and respiration, and peristalsis made MR imaging of the thorax and abdomen a major challenge. MR imaging of the abdomen started abdomen a major challenge. MR imaging of the abdomen started with the evaluation of solid visceral organs such as the liver and with the evaluation of solid visceral organs such as the liver and kidney. With technologic developments in MR hardware and kidney. With technologic developments in MR hardware and software occurring at a swift and steady pace, MR imaging of the software occurring at a swift and steady pace, MR imaging of the abdomen is beginning to expand beyond the solid viscera into the abdomen is beginning to expand beyond the solid viscera into the entire abdomen, including the hollow viscus of the GI tract.entire abdomen, including the hollow viscus of the GI tract.

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Basics of MRIBasics of MRI

• In order to read and understand an MR image, one must gain a basic In order to read and understand an MR image, one must gain a basic understanding of the principles underlying its production.understanding of the principles underlying its production.

• MR imaging is based on the naturally occurring magnetic moment that MR imaging is based on the naturally occurring magnetic moment that exists within the nuclei of a hydrogen atom, as well as its ubiquitous exists within the nuclei of a hydrogen atom, as well as its ubiquitous presence in organic tissue. When an external magnetic field is applied to presence in organic tissue. When an external magnetic field is applied to organic tissue, protons within hydrogen nuclei align themselves in parallel organic tissue, protons within hydrogen nuclei align themselves in parallel with this field and also begin to resonate. When a radiofrequency (RF) with this field and also begin to resonate. When a radiofrequency (RF) pulse is applied to these aligned protons, it provides enough energy to pulse is applied to these aligned protons, it provides enough energy to dislodge (or excite) them from this orientation. However, this is a dislodge (or excite) them from this orientation. However, this is a temporary phenomenon, and the nuclei relax back into realignment with temporary phenomenon, and the nuclei relax back into realignment with the external magnetic field. Upon relaxation, energy is released in the the external magnetic field. Upon relaxation, energy is released in the form of RF waves. This “echo” is detected and a signal of variable intensity form of RF waves. This “echo” is detected and a signal of variable intensity for a given location is produced.for a given location is produced.

• Tissue contrast is created because different tissues have different Tissue contrast is created because different tissues have different relaxation times. This is attributable to the different microenvironments relaxation times. This is attributable to the different microenvironments surrounding the magnetized nuclei. surrounding the magnetized nuclei.

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4 Key Parameters of MRI4 Key Parameters of MRI

• T1T1• T2T2• Echo Time (TE)Echo Time (TE)• Repetition Time (TR)Repetition Time (TR)• The relaxation times of protons shifting from a The relaxation times of protons shifting from a

higher to lower energy level, are referred to as T1 higher to lower energy level, are referred to as T1 and T2 and are tissue specific. and T2 and are tissue specific.

• The TE and TR are variables that can be The TE and TR are variables that can be controlled by an MR scanner operator.controlled by an MR scanner operator.

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T1 and T2 T1 and T2

• T1 and T2 represent relaxation time constants.T1 and T2 represent relaxation time constants.

• Each tissue has a specific, inherent T1 and T2 value.Each tissue has a specific, inherent T1 and T2 value.

• For example: fat has a short T1 and T2, whereas fluid has a long For example: fat has a short T1 and T2, whereas fluid has a long T1 and T2.T1 and T2.

• These values are measured in milliseconds.These values are measured in milliseconds.

• T1 – the time it takes nuclei in a particular tissue that has been T1 – the time it takes nuclei in a particular tissue that has been excited or “dislodged” from its parallel orientation to return to its excited or “dislodged” from its parallel orientation to return to its nonexcited state. (The time when about 63% of the original nonexcited state. (The time when about 63% of the original longitudinal magnetization is reached).longitudinal magnetization is reached).

• T2 – the time it takes nuclei in a particular tissue that has been T2 – the time it takes nuclei in a particular tissue that has been excited into a (phase coherent) transverse or perpendicular excited into a (phase coherent) transverse or perpendicular orientation to return to its non excited (non phase coherent) state. orientation to return to its non excited (non phase coherent) state. (The time when transverse magnitization decreases to 37% of the (The time when transverse magnitization decreases to 37% of the original value).original value).

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TR and TETR and TE

• These are two major parameters that can be adjusted (unlike T1 These are two major parameters that can be adjusted (unlike T1 and T2) to create the desired tissue differentiation.and T2) to create the desired tissue differentiation.

• When an MR image is taken, it begins with a magnetic field being When an MR image is taken, it begins with a magnetic field being established that is parallel with the bore of the scanner. This field established that is parallel with the bore of the scanner. This field has a strength on the order of 1-2 Teslas, depending on the has a strength on the order of 1-2 Teslas, depending on the scanner. Once this is established, and protons have aligned with scanner. Once this is established, and protons have aligned with the field, a sequence of radiofrequency (RF) pulses are the field, a sequence of radiofrequency (RF) pulses are administered. This excites the protons to a higher energy level. administered. This excites the protons to a higher energy level. This is then followed by relaxation back into a low energy state. This is then followed by relaxation back into a low energy state. This relaxation time is constant (T1 and T2). What can be This relaxation time is constant (T1 and T2). What can be changed however is the repetition time (TR) or time between changed however is the repetition time (TR) or time between administered RF pulses. What also can be manipulated is the time administered RF pulses. What also can be manipulated is the time that the RF “echo” is received by the RF detector. This time is that the RF “echo” is received by the RF detector. This time is referred to as TE, or echo time. referred to as TE, or echo time.

• By adjusting TE and TR, according to a tissue’s T1 and T2, the By adjusting TE and TR, according to a tissue’s T1 and T2, the various tissues in a region of interest can be differentiated. various tissues in a region of interest can be differentiated.

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T1 weighted images vs. T2 T1 weighted images vs. T2 weighted imagesweighted images• The following 2 slides offer graphs to help explain tissue The following 2 slides offer graphs to help explain tissue

contrast on T1 vs. T2 weighted images.contrast on T1 vs. T2 weighted images.• These graphs are depictions of the signal intensity as These graphs are depictions of the signal intensity as

function of time for two tissues types (fat and fluid) in an function of time for two tissues types (fat and fluid) in an external magnetic field. external magnetic field.

• A helpful way to analyze these graphs is to identify which A helpful way to analyze these graphs is to identify which curve provides the higher signal intensity (red or blue) at curve provides the higher signal intensity (red or blue) at the time point indicated by the dashed vertical line the time point indicated by the dashed vertical line (detection time). That point represents the tissue that will (detection time). That point represents the tissue that will appear brighter on the MR image.appear brighter on the MR image.

• Keep in mind that the TR and TE (along with the sequence Keep in mind that the TR and TE (along with the sequence of RF pulses) are what we can manipulate, while T1 and T2 of RF pulses) are what we can manipulate, while T1 and T2 are constant and tissue dependent. They are represented are constant and tissue dependent. They are represented by the degree of line curvature (exponential relationship) by the degree of line curvature (exponential relationship) on the graphs to follow. on the graphs to follow.

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T1 Weighted ImageT1 Weighted Image

TR

Signal Intensity

— fat— fluidTR = repetition timeTE = echo time

TE

T1 Weighted Image—short TR and TE

Although this is a gross oversimplification, when an image is T1 weighted, this means that the Although this is a gross oversimplification, when an image is T1 weighted, this means that the protocol used to scan a patient involves adjusting the TE and TR (shortening their times) in a protocol used to scan a patient involves adjusting the TE and TR (shortening their times) in a manner that will cause tissues with fast T1 and T2 relaxation times (e.g. fat) to appear brighter.manner that will cause tissues with fast T1 and T2 relaxation times (e.g. fat) to appear brighter.

In this graph In this graph fat has a fat has a greater signal greater signal intensity than intensity than fluid. Tissues fluid. Tissues with short T1 with short T1 and T2 (fat) and T2 (fat) will appear will appear brighter than brighter than those with those with longer T1 and longer T1 and T2 (fluid).T2 (fluid).

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T2 Weighted ImageT2 Weighted Image

TR

Signal Intensity

— fat— fluidTR = repetition timeTE = echo time

TE

T2 Weighted Image—long TR and TE

In this graph In this graph fluid has a fluid has a greater signal greater signal intensity than intensity than fat. Tissues fat. Tissues with long T1 with long T1 and T2 (fluid) and T2 (fluid) will appear will appear brighter than brighter than those with those with short T1 and short T1 and T2 (fat).T2 (fat).

•On a T2 weighted image the protocol used is one that On a T2 weighted image the protocol used is one that will result in tissue with long T1 and T2 (fluid) having a will result in tissue with long T1 and T2 (fluid) having a higher signal intensity. This is illustrated in the following higher signal intensity. This is illustrated in the following slides.slides.

•This protocol involves using a TR and TE that are This protocol involves using a TR and TE that are relatively longer than the T1 weighted sequence.relatively longer than the T1 weighted sequence.

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Beyond T1 and T2—Abdominal MRIBeyond T1 and T2—Abdominal MRI

• Along with the advancements in MR scanner hardware Along with the advancements in MR scanner hardware technology, developments in the pulse sequences used technology, developments in the pulse sequences used have led to the growing role of MRI in abdominal imaging.have led to the growing role of MRI in abdominal imaging.

• The fundamental principle behind these sequences is to The fundamental principle behind these sequences is to maximize contrast, resolution, speed, and coverage while maximize contrast, resolution, speed, and coverage while keeping motion and noise (relative to signal) at a minimum. keeping motion and noise (relative to signal) at a minimum.

• A list of commonly used sequences (acronyms provided) A list of commonly used sequences (acronyms provided) that capture abdominal anatomy and pathology include: that capture abdominal anatomy and pathology include: VIBE, HASTE, STIR, TSE, and GRE sequences. VIBE, HASTE, STIR, TSE, and GRE sequences.

• Although a description of all of these sequences is beyond Although a description of all of these sequences is beyond the scope of this atlas, a brief discussion of the VIBE the scope of this atlas, a brief discussion of the VIBE sequence can provide an introduction to the MR parameters sequence can provide an introduction to the MR parameters that are manipulated to achieve maximal contrast, that are manipulated to achieve maximal contrast, resolution, speed, and coverage.resolution, speed, and coverage.

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Volumetric Interpolated Breath-hold Volumetric Interpolated Breath-hold Examination (VIBE)Examination (VIBE)

• The VIBE Sequence is T1 based (short TR and TE).

• It is a complex 3D Fourier transform sequence that allows for fast acquisition time, thus reducing motion artifact and allowing for adequate coverage of the abdomen.

• In a given amount of time the VIBE sequence can provide better tissue contrast by utilizing a technique known as fat saturation.

• Given the relatively high resolution and coverage, VIBE sequences can be reconstructed and used for angiographic examinations.

• The axial, coronal, sagittal, and selected 3D reconstructions of the abdomen to follow were performed using the VIBE sequence.

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Anatomy of the AbdomenAnatomy of the Abdomen

Throughout this atlas, in axial, coronal, sagittal, and oblique 3D planes, Throughout this atlas, in axial, coronal, sagittal, and oblique 3D planes, we will highlight; we will highlight;

• LiverLiver• Biliary SystemBiliary System• PancreasPancreas• SpleenSpleen• Gastrointestinal TractGastrointestinal Tract• Kidneys Kidneys • RetroperitoneumRetroperitoneum• PeritoneumPeritoneum

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We have used images from We have used images from 3 different patients:3 different patients:

• Patient A - 32 year old femalePatient A - 32 year old female

MR settings: VIBE sequence, MR abdomenMR settings: VIBE sequence, MR abdomen

Planes: Axial, coronal, and sagittal; coronal MRCP imagePlanes: Axial, coronal, and sagittal; coronal MRCP image

• Patient B - 54 year old femalePatient B - 54 year old female

MR settings: VIBE sequence, MRA abdomen (focused on MR settings: VIBE sequence, MRA abdomen (focused on celiac/SMA)celiac/SMA)

Planes: Maximum intensity projection (MIP) 3D reconstruction Planes: Maximum intensity projection (MIP) 3D reconstruction

• Patient C - 27 year old malePatient C - 27 year old male

MR Settings: VIBE sequence, MRA abdomen (focused on renal MR Settings: VIBE sequence, MRA abdomen (focused on renal arteries)arteries)

Planes: Maximum intensity projection 3D reconstructionPlanes: Maximum intensity projection 3D reconstruction

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Pt A - Axial VIBEPt A - Axial VIBE

Plate 1Plate 1

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Plate 2Plate 2

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Pt A - Axial VIBE - Dome of the LiverPt A - Axial VIBE - Dome of the Liver

Liver

R. VentricleL. Ventricle

Esophagus

Azygos v.

Aorta

Inferior Vena Cava

R. Lower lobe of lung

L. Lower lobe of lung

Plate 3Plate 3

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Plate 4Plate 4

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Plate 5Plate 5

2020


Plate 6Plate 6

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Plate 7Plate 7

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Plate 8Plate 8

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Pt A - Axial VIBE - Hepatic VeinsPt A - Axial VIBE - Hepatic Veins

L. hepatic v.

M. hepatic v.

R. hepatic v.

Inferior vena cava

Spleen

Hemiazygos v.

Aorta

Gastroesophageal junction

Gastric fundus

Azygos v.

L. lower lobe of lung

L. Lobe of liver (lateral segment)

R. lobe of liver (posterior segment)

Plate 8Plate 8

R. lobe of liver (anterior segment)

L. Lobe of liver (medial segment)

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Plate 9Plate 9

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Plate 10Plate 10

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Pt A - Axial VIBE - Hepatic DivisionsPt A - Axial VIBE - Hepatic Divisions

Plate 10Plate 10

LLSLMS

RPS

RAS

LLS—Lateral segment of left lobe

LMS—Medial segment of left lobe

RAS—Anterior segment of right lobe

RPS—Posterior segment of right lobe

M. hepatic vein

R. hepatic vein

L. hepatic vein

Inferior vena cava

The superior aspect of the liver serves as a good reference point when inspecting axial images of the liver. It can be divided into 4 segments based on the alignment of the hepatic veins draining into the inferior vena cava. The dashed line indicates the respective course of the three hepatic veins. These segments can be further divided into superior and inferior segments.

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Plate 11Plate 11

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Plate 12Plate 12

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Pt A - Axial VIBE - Splenic HilumPt A - Axial VIBE - Splenic Hilum

Plate 12Plate 12

Splenic veinSplenic artery

Splenic flexurePosterior aspect of stomach

Posterior chest wall

Tail of pancreas

The spleen is an intraperitoneal structure, enclosed by peritoneum except at its hilum where the splenic vessels enter and leave. It can be readily differentiated from the kidney by its location adjacent to the posterolateral chest wall.

Important relationships of the spleen include abutment of the posterior aspect of the stomach as well as the tail of the pancreas

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Plate 13Plate 13

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Plate 14Plate 14

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Pt A - Axial VIBE - Adrenal Gland and SpleenPt A - Axial VIBE - Adrenal Gland and Spleen

Spleen

Ascending lumbar veins

Body of pancreas

AortaInferior vena cava

Gastric fundus

R. portal vein

L. portal vein

R. crus of diaphragm

L. crus of diaphragm

Spinal cord

Vertebral body

L. adrenal gland

Ascending lumbar veins

Plate 14Plate 14

R. adrenal gland

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Plate 15Plate 15

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Pt A - Axial VIBE - Adrenal GlandsPt A - Axial VIBE - Adrenal Glands

Plate 15Plate 15

This image illustrates the characteristic “inverted Y” appearance of the adrenal glands. The adrenal glands reside on the anteromedial and superior aspect of the kidneys.

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Plate 16Plate 16

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Plate 17Plate 17

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Pt A - Axial VIBE - Celiac TrunkPt A - Axial VIBE - Celiac Trunk

Celiac TrunkCommon hepatic a.

Aorta

Hepatic a. fossa

Portal vein

Inferior vena cava

L. adrenal gland

Spleen

Caudate lobe

L. kidney

R. kidney

Splenic flexure

Desc. colon

Ligamentum teres

Body of Pancreas

Gastric body

Plate 17Plate 17

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Plate 18Plate 18

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Plate 18Plate 18

Hepatic artery

Portal vein

Caudate lobe

Inferior vena cavaR. Adrenal gland (see plates 20-24)

A notable anatomic relationship exists at the level of the right adrenal gland that involves a posterior to anterior sequence of structures that line up in a relatively linear fashion. These include, from posterior to anterior—R. adrenal gland, IVC, caudate lobe, portal vein, and hepatic artery.

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Plate 19Plate 19

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Pt A - Axial VIBE - Body of PancreasPt A - Axial VIBE - Body of Pancreas

Ligamentum teresL. lobe (medial)

L. lobe (lateral)

Porta hepatisPortal

veinHepatic arteryInferior vena cava

Superior mesenteric artery

Splenic vein

Gastric body

Descending colon

Small bowel

R. kidney

L. kidney

Neck of gallbladder

Body of pancreas

Spleen

Aorta

Pancreatic duct

Plate 19Plate 19

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Plate 20Plate 20

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Plate 21Plate 21

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Pt A - Axial VIBE - Origin of SMAPt A - Axial VIBE - Origin of SMA

Descending colon

Neck of gallbladder

Body of pancreas

L. kidney

R. kidney

Small bowel

Gastric body

Splenic vein

Inferior vena cava

Hepatic artery

Neck of pancreas

Ligamentum teres

Portal vein


Porto-splenic confluence

Gastric antrum

R. renal vein

Aorta

Plate 21Plate 21

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Plate 22Plate 22

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Pt A - Axial VIBE - Relationships of the Pt A - Axial VIBE - Relationships of the Superior Mesenteric ArterySuperior Mesenteric Artery

Plate 22Plate 22

Body of pancreas Superior mesenteric artery (SMA)

L. Renal vein

Aorta

Splenic veinThis slide shows another important relationship that exists surrounding the SMA. There are four structure to be aware of. These include the body of the pancreas and splenic artery, which pass over the SMA anteriorly. Posteriorly, the duodenum and left renal vein cross behind the SMA. In this particular image, the transverse aspect of the duodenum is out of plane leaving a small distal portion visible.

Distal duodenum

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Plate 23Plate 23

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Plate 24Plate 24

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Pt A - Axial VIBE - Origin of the Renal Pt A - Axial VIBE - Origin of the Renal ArteriesArteries

L. renal artery

Hilum of right kidney

Gastric bodyGastric antrum

Small bowelBody of gallbladder

Inferior vena cava

Superior mesenteric vein

Ligamentum teres fissure


Head of pancreas Hilum of left kidney

Hepatic flexure

L. renal veinDuodenum (1st part)

Duodenum (2nd part)

Falciform ligament

Plate 24Plate 24

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Plate 25Plate 25

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Pt A - Axial VIBE - Clinical Relationships of Pt A - Axial VIBE - Clinical Relationships of the GallBladderthe GallBladder

An important clinical relationship exists between the gallbladder and the GI tract. In this image the hepatic flexure lies adjacent and medial to the body of the gallbladder. As the gallbladder ascends its neck abuts the superior and/or descending duodenum (which in this image lies medial to the flexure, see plate 59). In gallstone ileus, a stone from the gallbladder tracks through the wall of the gallbladder and enters the duodenum causing obstruction at the narrow lumen of the ileocecal valve. If the stone forms a fistula with the hepatic flexure, and enters the colon, ileus is unlikely due to the wide colonic lumen.

Gallbladder

Hepatic flexureDuodenum (descending)

Plate 25Plate 25

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Plate 26Plate 26

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Plate 27Plate 27

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Pt A - Axial VIBE - Renal HilumPt A - Axial VIBE - Renal Hilum

Quadratus lumborum

Hilum of right kidney

Hilum of left kidney

Duodenum (2st part)

Small bowelL. renal vein

Body of gallbladder

Inferior vena cava

Ligamentum teres fissureHead of pancreas

Duodenum (3nd part)

R. renal pelvis

Renal pelvis fat

Transverse colon

Deep back muscles

Hepatic flexure

Psoas muscle


Hepatorenal recess (Morrison’s pouch)


Plate 27Plate 27

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Plate 28Plate 28

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Plate 29Plate 29

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Pt A - Axial VIBE - Kidney and RetroperitoneumPt A - Axial VIBE - Kidney and Retroperitoneum

Plate 29Plate 29

The kidneys are retroperitoneal structures that reside at the level of T12 to L3, with the right typically being lower than the left due to the presence of the liver. It is encapsulated and housed, along with the adrenal glands, within the perirenal space. This space is surrounded by Gerota’s fascia. The anterior and posterior pararenal space surround Gerota’s fascia with an additional layer of adipose tissue (see slide 74 for a more detailed look at the retroperitoneum).

These retroperitoneal locations have clinical relevance when staging for renal cell carcinoma or assessing for renal infection or trauma.

In terms of relations, the kidney is well connected, coming into contact (through peri- and pararenal spaces) bilaterally with the adrenals and diaphragm superiorly and the quadratus lumborum and psoas muscles inferomedially. On the right side the kidney is adjacent to the liver, duodenum, and ascending colon. On the left side the kidney is in contact with spleen, stomach, pancreas, jejunum, and descending colon.

Posterior pararenal space

Perirenal space

Kidney

Perirenal space

Anterior pararenal space

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Plate 30Plate 30

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Pt A - Axial VIBE - Hepatic FlexurePt A - Axial VIBE - Hepatic Flexure

Transverse colon

Deep back muscles

Ureter

Hepatic flexure

Quadratus lumborum

Psoas muscle


Small bowel


Fundus of gallbladder Anterior pararenal

space*

Posterior pararenal space*

Perirenal space*Lumbar vessels

Inferior vena cava

Aorta

Flank stripe*

Duodenum

* Marked structures of retroperitoneum will be discussed in the following slide.

Plate 30Plate 30

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A Simplified Overview of the A Simplified Overview of the Retroperitoneal SpacesRetroperitoneal Spaces

Gastric body

Spleen

Liver

Inferiorvena cava

AnteriorPararenalspace

PosteriorPararenalspace

Perirenal space

Pancreas

Flank stripe

Right kidney

Left kidney

TransversalisfasciaGerota’sfascia

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Plate 31Plate 31

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Plate 32Plate 32

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Plate 33Plate 33

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Pt A - Axial VIBE - Lower Poles of KidneysPt A - Axial VIBE - Lower Poles of Kidneys

Transverse colon

Quadratus lumborum

Psoas muscle

Small bowelInferior vena cava

Fundus of gall bladder

Aorta

L. ureter

Erector spinae

LiverR. ureter

Plate 33Plate 33

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Plate 34Plate 34

6666


Plate 35Plate 35

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Plate 36Plate 36

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Plate 37Plate 37

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Plate 38Plate 38

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Plate 39Plate 39

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Plate 40Plate 40

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Pt A - Coronal Plane - VIBE ReformattedPt A - Coronal Plane - VIBE Reformatted

Plate 41Plate 41

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Plate 42Plate 42

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Pt A - Coronal Plane - VIBE ReformattedPt A - Coronal Plane - VIBE ReformattedGallbladderGallbladder

Hepatic flexure

Gastric body

Liver

Gallbladder

Diaphragm

Ligamentum teres

R. ventricle

Small bowel

Falciform ligament

Transverse colon

Plate 42 Plate 42

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Plate 43 Plate 43

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Plate 44Plate 44

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Pt A - Coronal Plane - VIBE ReformattedPt A - Coronal Plane - VIBE ReformattedTransverse ColonTransverse Colon

Hepatic flexure

Gastric body

Gastric antrumSplenic flexure

Diaphragm

L. ventricle

R. ventricle

Small bowel

Portal vein

Transverse colon

R. lobe of liver

Fundus of gallbladder

L. lobe of liver

Gastric fundus

Plate 44Plate 44

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Plate 45 Plate 45

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Plate 46Plate 46

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Pt A - Coronal Plane - VIBE ReformattedPt A - Coronal Plane - VIBE ReformattedPancreas and Splenic and Superior Mesenteric VeinPancreas and Splenic and Superior Mesenteric Vein

Neck of pancreas

Body of pancreas


The pancreas is a retroperitoneal structure that has many close anatomic relations. One such relation occurs posterior to the neck of the pancreas, and involves the union of the splenic vein and superior mesenteric vein (SMV) to form the portal vein. This image is in the plane of the pancreas and the more anteriorly situated SMV.

The pancreas can be subdivided into five segments. They include a head, neck, uncinate process, body and tail.

In this image, the body and neck of the pancreas are located centrally, anterior to the splenic vein (out of plane).

Plate 46 Plate 46

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Plate 47Plate 47

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Pt A - Coronal Plane - VIBE ReformattedPt A - Coronal Plane - VIBE ReformattedUnion of Splenic and Superior Mesenteric Union of Splenic and Superior Mesenteric VeinsVeins

Splenic v.

Gastric body/fundus

Hepatic flexure

Superior mesenteric a.

Portal veinR. and L.hepaticarteries

Abdominal aorta

R. ventricle

L. ventricle

Small bowel

Neck of pancreas

Body of pancreas

Duodenum (descending)

Splenic flexure

Diaphragm

Head of pancreas

Gallbladder

Ascending colon

Superior mesenteric v.

Plate 47 Plate 47

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Plate 48Plate 48

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Pt A - Coronal Plane - VIBE ReformattedPt A - Coronal Plane - VIBE ReformattedBranching of the Celiac arteryBranching of the Celiac artery

Inferior vena cava

R. ventricleL. ventricle

Small bowel

Aorta

Portal vein


Hepatic flexure

Celiac artery

Gastric body/fundus

Splenic v.

L. gastric artery

Body of pancreas

Ligamentum teres

Hepatic artery

Plate 48Plate 48

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Plate 49Plate 49

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Pt A - Coronal Plane - VIBE ReformattedPt A - Coronal Plane - VIBE ReformattedPortal VeinPortal Vein

Portal veinSuperior mesenteric a.

Hepatic flexure

Celiac arterySpleen

L. ventricle

Gastric fundus

Splenic v.

Right hepatic vein

Small bowel

R. atrium

Abdominal aorta

Body of pancreas

L. renal veinInferior vena cava

Inferior vena cava

Plate 49Plate 49

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Plate 50Plate 50

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Pt A - Coronal Plane - VIBE ReformattedPt A - Coronal Plane - VIBE ReformattedCourse of the Inferior Vena Cava (IVC)Course of the Inferior Vena Cava (IVC)

Ascending from the confluence of the common iliac veins the IVC travels parallel and a few centimeters to the right of the vertebral column. The IVC crosses anterior to the right renal artery, receiving the right and left renal vein. The left renal vein crosses over the aorta anterior and parallel to the left renal artery.

Along with also receiving gonadal, suprarenal, and lumbar veins along this course, the IVC next passes along the inferior visceral border of the liver where it receives input from the three hepatic veins.

Following this the IVC passes through the vena caval foramen to then enter the right atrium.

This image illustrates the IVC passing the right renal artery anteriorly, the liver posteriorly, and entering the right atrium of the heart.

Right atrium

IVC

Right renal artery

IVC

Plate 50 Plate 50

8989


Plate 51 Plate 51

9090

Pt A - Coronal Plane - VIBE ReformattedPt A - Coronal Plane - VIBE ReformattedEsophagogastric JunctionEsophagogastric Junction

Body of pancreas

Inferior vena cava

Spleen

Psoas muscles

Aorta

Splenic v.

Superior branch of portal veinInferior branch of portal vein

Esophagus

Small bowel

Gastric cardia

Celiac artery

Hepatic flexure

R. atrium

L. renal arteries

Plate 51Plate 51

9191


Plate 52Plate 52

9292


Plate 53 Plate 53

9393

Pt A - Coronal Plane - VIBE ReformattedPt A - Coronal Plane - VIBE ReformattedAdrenal GlandsAdrenal Glands

Thoracic aorta

Hepatic vein

Hepatorenal recess

R. kidney

Spleen

Psoas m.

L. kidney

Splenic v.

Right renal arteries

L. renal arteries

Inferior vena cava

R. adrenal gland L. adrenal gland

Gastric cardia

Abdominal aorta

Plate 53 Plate 53

9494


Plate 54Plate 54

9595


Plate 55 Plate 55

9696


Plate 56 Plate 56

9797

Pt A - Coronal Plane - VIBE ReformattedPt A - Coronal Plane - VIBE ReformattedRenal Hilum and T12 Vertebral BodyRenal Hilum and T12 Vertebral Body

Thoracic aorta

Hemiazygos v

Hepatic vein

Serratus anterior m.

Renal sinus fat

Hepatorenal recess

R. kidney

R. lower lobe of lungL. lower lobe of lung

Spleen

R. psoas m.

L. renal pelvisL. kidney

L. renal calyxSplenic hilum

L. psoas m.

Plate 56 Plate 56

9898


Plate 57Plate 57

9999

Pt A - Coronal Plane - VIBE ReformattedPt A - Coronal Plane - VIBE ReformattedSplenic HilumSplenic Hilum

Right lobe of liver (posterior segment)

Serratus anterior m.

Renal calyxHepatorenal recess

R. kidney

R. lower lobe of lung


SpleenSplenic hilum

Splenic artery

Spinal canal

Thoracic aorta

L. kidney

R. psoas m.

L. psoas m.

Plate 57Plate 57

100100


Plate 58Plate 58

101101


Plate 59 Plate 59

102102


Plate 60 Plate 60

103103

Pt A - Coronal Plane - VIBE ReformattedPt A - Coronal Plane - VIBE ReformattedSpinal Canal at T10/Posterior KidneysSpinal Canal at T10/Posterior Kidneys

Right lobe of liver (posterior segment)

Spinal canal

Spleen

Spinal cord

Perirenal fat

Erector spinae m.

Hepatorenal recess

R. lower lobe of lung

R. kidney


L. kidney

Plate 60 Plate 60

104104

Pt A - Sagittal Plane - VIBE ReformattedPt A - Sagittal Plane - VIBE Reformatted

Plate 61 Plate 61

105105


Plate 62 Plate 62

106106


Plate 63 Plate 63

107107

Pt A - Sagittal Plane - VIBE ReformattedPt A - Sagittal Plane - VIBE ReformattedRight Lobe of LiverRight Lobe of Liver

Liver (vertical span)Anterior ribs

Subcutaneous fat

R. lung

Posterior ribsIntercostal m.

Plate 63Plate 63

108108


Plate 64 Plate 64

109109


Plate 65Plate 65

110110

Pt A - Sagittal Plane - VIBE ReformattedPt A - Sagittal Plane - VIBE ReformattedGallbladderGallbladder

Gallbladder Perirenal fat

Posterior pararenal fat

Hepatorenal recess

Ascending colon

R. kidney

R. lobe of liver (posterior segment)

R. lobe of liver (anterior segment)

Branch of portal vein

Transverse colon

Hepatic veins

Plate 65 Plate 65

111111


Plate 66 Plate 66

112112

Pt A - Sagittal Plane - VIBE ReformattedPt A - Sagittal Plane - VIBE ReformattedHepatorenal RecessHepatorenal Recess

3030

Hepatorenal Recess

The peritoneal recess between the liver and kidney occupies an important clinical location in the abdomen. In the supine position this recess, also known as “Morrison’s pouch”, is the lowest point where fluid (e.g ascites) can collect.

Superior

Anterior

Anterior

Superior

Plate 66 Plate 66

113113


Plate 67Plate 67

114114

Pt A - Sagittal Plane - VIBE ReformattedPt A - Sagittal Plane - VIBE ReformattedMedulla of Right KidneyMedulla of Right Kidney

Body of gallbladder

Hepatic veins

Renal calyx

Pararenal fat

R. kidney (cortex)

R. Kidney (medulla)

Portal vein

R. Lobe of liver (anterior segment)

R. Lobe of liver (posterior segment)

Hepatic flexure

Plate 67 Plate 67

115115


Plate 68 Plate 68

116116

Pt A - Sagittal Plane - VIBE ReformattedPt A - Sagittal Plane - VIBE ReformattedPorta hepatisPorta hepatis

Hepatic artery

Common bile duct

Portal vein

The porta hepatis is the “port” of entrance and exit to and from the liver for the portal triad—portal vein, hepatic artery, and common bile duct. This sagittal MR image provides a cross section of the portal triad.

Plate 68 Plate 68

117117


Plate 69Plate 69

118118

Pt A - Sagittal Plane - VIBE ReformattedPt A - Sagittal Plane - VIBE ReformattedInferior Vena CavaInferior Vena Cava

Inferior vena cava

Hepatic artery

Psoas m.

R. lumbar vesselsPortal vein

Plate 69 Plate 69

119119


Plate 70Plate 70

120120


Plate 71Plate 71

121121

Pt A - Sagittal Plane - VIBE ReformattedPt A - Sagittal Plane - VIBE ReformattedSuperior Mesenteric VeinSuperior Mesenteric Vein


Liver

Thoracic aorta

Head of pancreasSpinal canal

Hepatic flexureDuodenumUncinate process

Hepatic artery

Abdominal aorta

Inferior vena cava

Plate 71 Plate 71

122122


Plate 72 Plate 72

123123

Pt A - Sagittal Plane - VIBE ReformattedPt A - Sagittal Plane - VIBE ReformattedAorta, Celiac Artery, and Superior Mesenteric ArteryAorta, Celiac Artery, and Superior Mesenteric Artery

Splenic vein

Duodenum (transverse)

Neck of pancreas

Left lobe of liver


Celiac artery

Duodenum (superior)

L. renal vein

Ascending colon

Transverse colon

Esophago-gastric junction

Aorta

Hepatic artery

Plate 72 Plate 72

124124


Plate 73 Plate 73

125125


Plate 74 Plate 74

126126


Plate 75 Plate 75

127127

Pt A - Sagittal Plane - VIBE ReformattedPt A - Sagittal Plane - VIBE ReformattedMedulla of Left KidneyMedulla of Left Kidney

Gastric body

Left lobe of liver (lateral segment)

Left kidney (medulla)

Transverse colon

Left kidney (cortex)

Spleen

Gastric fundus

Renal calyx

Pancreatic body and tail

Small bowel

Perirenal fat

Plate 75 Plate 75

128128


Plate 76 Plate 76

129129

Pt A - Sagittal Plane - VIBE ReformattedPt A - Sagittal Plane - VIBE ReformattedLesser SacLesser Sac

Gastric fundus

Gastric body

Body and tail of pancreas

In this image, the lesser sac can be seen on end as a thin hypointense area between the stomach and the pancreas.

The lesser sac is a blind pouch of peritoneum that is bordered antero-superiorly by the posterior wall of the stomach and the lesser omentum and postero-inferiorly by the peritoneum overlying the body of the pancreas.

Plate 76Plate 76

130130


Plate 77Plate 77

131131

Pt A - Sagittal Plane - VIBE ReformattedPt A - Sagittal Plane - VIBE ReformattedSpleenSpleen

Spleen

Splenic flexure

Small bowel

Apex of heart

Splenic veinGastric body

Left kidney

Plate 77 Plate 77

132132

Pt B - MRA with contrast, maximum Pt B - MRA with contrast, maximum intensity projection 3D intensity projection 3D

reconstruction of superior reconstruction of superior mesenteric and celiac arteriesmesenteric and celiac arteries

Plate 78Plate 78

133133



Aorta

Hepatic artery

R. renal artery


Celiac trunk

Splenic arteryGastroduodenal

artery

Plate 78Plate 78

134134



Plate 79 Plate 79

135135



Aorta

Hepatic artery Splenic artery

Celiac trunk


Lumbar arteries

L. renal artery

R. renal artery

Plate 79 Plate 79

136136



Plate 80 Plate 80

137137



Plate 81Plate 81

138138



Plate 82 Plate 82


Celiac trunk

Inferior mesenteric artery

139139



Plate 83 Plate 83

140140



Celiac trunk


Hepatic artery

Left gastric artery

Splenic artery

Lumbar arteries

Plate 83 Plate 83

141141

Pt C - MRA with contrast, maximum Pt C - MRA with contrast, maximum intensity projection 3D intensity projection 3D

reconstruction of renal arteriesreconstruction of renal arteries

Plate 84 Plate 84

142142



Right renal arteryLeft renal artery

AortaSuperior mesenteric artery

Lumbar arteries

L. ureter

Plate 84 Plate 84

143143



Plate 85Plate 85

144144



Plate 86 Plate 86

145145




Aorta

L. Ureter

Right renal artery

Left renal artery

Plate 86Plate 86

146146



Plate 87 Plate 87

147147



Aorta


L. Renal artery

Branches of L. renal artery

Plate 87 Plate 87

148148

Correlation of Axial, Coronal, and Sagittal MR Plate Correlation of Axial, Coronal, and Sagittal MR Plate 11Liver and Gastroesophageal junctionLiver and Gastroesophageal junction

When examining the GI tract, a useful tool for orientation is the stomach. If one follows axial slices in the caudal direction from the diaphragm and GE junction downward, an easy landmark of the stomach is its characteristic longitudinally oriented rugae. These provide an initial reference point from which one can follow the GI tract distally through the duodenum to its distal transverse and ascending segments.

149149

Correlation of Axial, Coronal, and Sagittal MR Plate Correlation of Axial, Coronal, and Sagittal MR Plate 22SpleenSpleen Given its

location immediately adjacent to the posterior and lateral ribs and its lack of surrounding adipose tissue (unlike the kidneys), the spleen is very susceptible to trauma. MR imaging of the abdomen can serve as a useful tool in assessing splenic trauma.

150150

Correlation of Axial, Coronal, and Sagittal MR Plate Correlation of Axial, Coronal, and Sagittal MR Plate 33Celiac TrunkCeliac Trunk

The celiac artery arises off of the aorta at the level of T12. It trifurcates into the splenic, hepatic and left gastric arteries. These arteries supply the foregut of the GI tract—distal esophagus, stomach, duodenum, pancreas, liver, gall bladder, and spleen.

151151

Correlation of Axial, Coronal, and Sagittal Plate 4Correlation of Axial, Coronal, and Sagittal Plate 4PancreasPancreas

Together these images capture the body and tail of the pancreas. To image the entire view of the pancreas an oblique section can be helpful.

152152

The The PancreasPancreas

This image illustrates four main segments of the pancreas in one plane.

These include the tail, body, neck, and head of the pancreas.

Due to the fact that the pancreas typically slopes inferiorly from the tail at the splenic hilum to its head adjacent to the duodenum, this image was reconstructed in an oblique plane.

Head

Neck

Body

Tail

153153

Correlation of Axial, Coronal, and Sagittal MR Plate Correlation of Axial, Coronal, and Sagittal MR Plate 55GallbladderGallbladder

Fluid is hypointense (dark) on these T1 weighted VIBE images. The fluid-filled gallbladder illustrates this appearance. To further examine the gallbladder and biliary tree, T2 weighted MRCP (MR cholangiopancreatography) can be used.

154154

MRCP of the Biliary TreeMRCP of the Biliary Tree

Pancreatic duct

L. Hepatic duct

Common bile duct

Common hepatic duct

R. hepatic duct

Gallbladder

Cystic duct

155155

Correlation of Axial, Coronal, and Sagittal MR Plate Correlation of Axial, Coronal, and Sagittal MR Plate 66Kidney (Right Upper Pole)Kidney (Right Upper Pole)

156156

Correlation of Axial, Coronal, and Sagittal Plate 7Correlation of Axial, Coronal, and Sagittal Plate 7Kidney (Left Hilum)Kidney (Left Hilum)

157157

Correlation of Axial, Coronal, and Sagittal MR Plate Correlation of Axial, Coronal, and Sagittal MR Plate 88Kidneys (Left Lower Pole) and Vertebral MusculatureKidneys (Left Lower Pole) and Vertebral Musculature

Vertebral body

Quadratus lumborum

Erector spinae

Psoas muscle

Ureter

The lower poles of the kidneys lie adjacent and antero-lateral to the muscles of the back. These include the psoas, quadratus lumboratum, deep back muscles, and intermediate (erector spinae) back muscles.

Notice the small hypointense circular slice of the left ureter lying on the left psoas muscle.

Deep back mm.

158158

ReferencesReferences

Christofordis, A Christofordis, A Atlas of Axial, Sagittal, and Coronal Anatomy Atlas of Axial, Sagittal, and Coronal Anatomy with CT and MRI with CT and MRI 1988 1988

Novelline, RA Novelline, RA Living Anatomy: A Working Atlas Using Computed Tomography, Magnetic Resonance, and Angiography Images 1st edition, 1987

Moore, K and Dalley, A Moore, K and Dalley, A Clinically Oriented AnatomyClinically Oriented Anatomy 4 4thth edition, 1999edition, 1999

Fleckenstein, P Fleckenstein, P Anatomy in Diagnostic ImagingAnatomy in Diagnostic Imaging 2 2ndnd edition, edition, 20012001

159159

Special ThanksSpecial Thanks

Pamela Lepkowski, Education Pamela Lepkowski, Education Coordinator at Beth Israel Deaconess Coordinator at Beth Israel Deaconess Medical Center for technical Medical Center for technical assistance and editing.assistance and editing.

mri atlas of the abdomen (a self-guided tutorial)

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