DOI:10.2214/AJR.07.3756
AJR 2008; 191:1082-1092
© American Roentgen Ray Society
Duodenal Abnormalities at MR Small-Bowel Follow-Through
Carmel G. Cronin1,
Derek G. Lohan,
Eithne DeLappe,
Clare Roche and
Joseph M. Murphy
1 All authors: Department of Radiology, University College Hospital, Galway,
Ireland.
Received January 31, 2008;
accepted after revision May 1, 2008.
Address correspondence to C. G. Cronin
(carmelcronin2000{at}hotmail.com).
Abstract
OBJECTIVE. The cross-sectional characterization of duodenal
abnormalities is plagued with inadequacy, a reflection of the meandering
course of this segment of the bowel. We consider the imaging appearance of
such abnormalities at MRI small-bowel follow-through, illustrating the typical
manifestations of each pathologically confirmed condition.
CONCLUSION. MRI small-bowel follow-through allows confident duodenal
evaluation because of a combination of sufficient luminal distention and
multiplanar versatility. Diseases of the duodenum may have a variety of
manifestations at MRI small-bowel follow-through, the knowledge of which may
aid in confident noninvasive patient diagnosis.
Keywords: abdominal imaging • duodenum • gastrointestinal tract • MRI • small bowel
Introduction
MRI small-bowel follow-through has recently been suggested as a possible
alternative to conventional fluoroscopic enteroclysis in small-bowel
evaluation, a physically and mentally traumatic experience for the patient
that necessitates duodenal intubation
[1]. Indeed, enteroclysis often
precludes duodenal assessment, a reflection of its requirement for tube
positioning at or distal to the duodenojejunal junction in an attempt to avoid
gastroesophageal reflux and potential aspiration of contrast material. MRI
small-bowel follow-through offers a number of distinct advantages over
projectional and other cross-sectional techniques—namely, the absence of
associated ionizing radiation exposure, multiplanar imaging capabilities,
superb spatial and contrast resolution, facilitation of sequential imaging
over prolonged periods of time (and thus intermittent evaluation of enteric
motility), and obviating potentially nephrotoxic contrast medium. Many
duodenal abnormalities that we illustrate were found incidentally, reminding
us not to forget the duodenum, and highlighting the need for a thorough
assessment. Undoubtedly many of these duodenal abnormalities are well known to
the reviewer; however, we describe the imaging manifestations at MRI
small-bowel follow-through, illustrating features that may aid in their
differentiation. To our knowledge, such a description has not previously been
undertaken, making this a valuable addition to the current literature.
Technique
We instruct all patients to fast from the preceding 12:00 midnight. No
bowel preparation, medications to promote gastric emptying or bowel
relaxation, or paramagnetic contrast agents are administered before imaging.
Bowel distention is achieved using a single packet of polyethylene glycol
(PEG) solution (Klean-Prep, Norgine) diluted in 1,000 mL of water and a small
amount of orange flavoring to render the mixture more palatable. This solution
is ingested over a 10- to 20-minute period, as permitted by patient tolerance.
PEG (macrogol 3350, 59.0 g; anhydrous sodium sulfate, 5.685 g; sodium
bicarbonate, 1.685 g; sodium chloride, 1.465 g; potassium chloride, 0.7425 g)
is a high-osmolarity, nonabsorbed contrast medium that provides excellent
intraluminal contrast and luminal distention. All patients are provided with
an information sheet detailing the procedure and the potential risk of
diarrhea caused by PEG before their appointment.
Initial images are obtained 20 minutes after contrast ingestion
irrespective of the patient's ability to consume the full contrast mixture
[2–5].
We perform all studies on a Symphony 1.5-T MRI system (Siemens Medical
Solutions) equipped with high-performance gradient coils characterized by a
maximum gradient amplitude of 52 mT/m and a slew rate of 125 T/m/s. Large
flexible surface coils were also used. Axial and coronal steady-state free
precession (true FISP) acquisitions are obtained with the patient in the
supine position and during suspended inspiration, with the field of view
encompassing from the diaphragm to the symphysis pubis (TR/TE, 4.72/2.36;
section thickness, 8 mm for axial [distance factor, 20%] and 5 mm for coronal
[distance factor, 0%] images). Subsequent paired axial and coronal
acquisitions are then obtained at 20-minute intervals as required until
completion. Examination completion is defined as the presence of contrast
material in the cecum or further distally, having achieved prior
diagnostic-quality distention of the small bowel throughout its length.
Benign Findings
Small-Bowel Malrotation
Small-bowel malrotation results from failure of a normal pattern of torsion
and detorsion during embryologic development. As a result, the duodenojejunal
flexure does not occupy a correct position to the left side of the left L1
pedicle. Indeed, the duodenum and jejunum may not cross the midline at all,
remaining on the right side of the abdomen, with the large bowel located
predominantly or completely to the left. The duodenum does not course between
the aorta and the superior mesenteric artery in cases of malrotation. An
abnormal location of small and large bowels may be supported by reversal of
the superior mesenteric arterial and venous relationship, so that the artery
is located to the right of the vein
[6] (Fig.
1A,
1B,
1C). MRI small-bowel
follow-through is ideal for the investigation of suspected enteric
malrotation. This technique allows comprehensive duodenal, small-bowel, and
large-bowel mapping so that the locations of each may be confidently
determined. Additional extraluminal information is also readily accessible,
most notably evaluation of the superior mesenteric arterial–venous
relationship. MRI small-bowel follow-through may also benefit evaluation of
suspected complications of malrotation, including intestinal obstruction, an
entity of increased prevalence in the population of patients with malrotation
[7].
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Fig. 1A —34-year-old man with nonspecific abdominal pain. Axial MRI
small-bowel follow-through reveals abnormal anterior relationship of third
part of duodenum relative to superior mesenteric vessels (white
arrows, A). Compression and torsion of duodenum as it courses
anteriorly results in beak sign (arrowhead, A). At same level,
superior mesenteric vein passes posterior to superior mesenteric artery,
creating "swirl sign" (black arrow, A). Further
distally, duodenum courses posteriorly around mesenteric vessels, providing
corkscrew appearance (white arrows, B and C). High
cecum (curved black arrows, A–C) and terminal ileum
(curved white arrow, B and C) are shown. These findings
are typical of malrotation.
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Fig. 1B —34-year-old man with nonspecific abdominal pain. Axial MRI
small-bowel follow-through reveals abnormal anterior relationship of third
part of duodenum relative to superior mesenteric vessels (white
arrows, A). Compression and torsion of duodenum as it courses
anteriorly results in beak sign (arrowhead, A). At same level,
superior mesenteric vein passes posterior to superior mesenteric artery,
creating "swirl sign" (black arrow, A). Further
distally, duodenum courses posteriorly around mesenteric vessels, providing
corkscrew appearance (white arrows, B and C). High
cecum (curved black arrows, A–C) and terminal ileum
(curved white arrow, B and C) are shown. These findings
are typical of malrotation.
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Fig. 1C —34-year-old man with nonspecific abdominal pain. Axial MRI
small-bowel follow-through reveals abnormal anterior relationship of third
part of duodenum relative to superior mesenteric vessels (white
arrows, A). Compression and torsion of duodenum as it courses
anteriorly results in beak sign (arrowhead, A). At same level,
superior mesenteric vein passes posterior to superior mesenteric artery,
creating "swirl sign" (black arrow, A). Further
distally, duodenum courses posteriorly around mesenteric vessels, providing
corkscrew appearance (white arrows, B and C). High
cecum (curved black arrows, A–C) and terminal ileum
(curved white arrow, B and C) are shown. These findings
are typical of malrotation.
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Diverticula
Duodenal diverticula are believed to be due to abnormalities of luminal
recanalization during embryologic development. They occur most frequently
along the medial wall of the second and third duodenal segments
[6,
8]. Although most are
asymptomatic, inflammation in the form of duodenal diverticulitis may occur.
At MRI small-bowel follow-through, diverticula manifest as contrast-filled
outpouchings of the duodenal lumen
[9] (Fig.
2A,
2B). Direct luminal continuity
with the duodenum is an important feature to aid differentiation from
pancreatic or choledochal cysts on these predominantly T2-weighted sequences.
The presence of associated inflammation may be inferred by identification of
adjacent fat stranding.
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Fig. 2A —62-year-old man with incidentally detected diverticulum. MRI
small-bowel follow-through shows diverticulum arising from descending (second)
duodenal segment (black arrows) and direct continuity with duodenal
wall (white arrow, B) and lumen. Presence of wide neck
facilitates inflow of ingested polyethylene glycol contrast material.
Air–fluid level is seen on axial view (B).
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Fig. 2B —62-year-old man with incidentally detected diverticulum. MRI
small-bowel follow-through shows diverticulum arising from descending (second)
duodenal segment (black arrows) and direct continuity with duodenal
wall (white arrow, B) and lumen. Presence of wide neck
facilitates inflow of ingested polyethylene glycol contrast material.
Air–fluid level is seen on axial view (B).
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Intussusception
Duodenal intussusception is a rare entity because of the somewhat fixed
retroperitoneal position of the duodenum. When encountered, intussusception
more often occurs in the presence of a duodenal neoplasm, benign or malignant,
that acts as a lead point for mucosal enveloping. The classically described
coiled-spring appearance, often appreciable in the jejunum and occurring as a
result of invagination of a proximal bowel segment into a distal segment, may
not be appreciable in the duodenum because of its fixed position. Diagnosis of
duodenal intussusception on MRI small-bowel follow-through rarely poses a
diagnostic dilemma, a testament to the ease of mural identification and
evaluation. Segmental duodenal mural duplication, providing a
wall-within-a-wall appearance, is pathognomonic (Fig.
3A,
3B). MRI small-bowel
follow-through also affords the opportunity to evaluate for the presence of an
underlying neoplastic process acting as lead point.
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Fig. 3A —67-year-old man with history of duodenal mobilization during
recent abdominal aortic aneurysm repair (star). Abdominal CT (not
shown) was initially performed for evaluation of sudden severe epigastric pain
with intractable vomiting, and revealed gastric and proximal duodenal dilation
in presence of a duodenal mass. Axial (A) and coronal (B) MRI
small-bowel follow-through acquisitions, performed to characterize mass, show
coiled-spring appearance of duodenal intussusception (straight white
arrows). Duodenal wall is thickened (straight black arrow,
A) with surrounding edema (curved white arrow, A) and
fat stranding (curved black arrow, A). Duodenum is dilated
proximal to intussusception, despite nasogastric decompression.
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Fig. 3B —67-year-old man with history of duodenal mobilization during
recent abdominal aortic aneurysm repair (star). Abdominal CT (not
shown) was initially performed for evaluation of sudden severe epigastric pain
with intractable vomiting, and revealed gastric and proximal duodenal dilation
in presence of a duodenal mass. Axial (A) and coronal (B) MRI
small-bowel follow-through acquisitions, performed to characterize mass, show
coiled-spring appearance of duodenal intussusception (straight white
arrows). Duodenal wall is thickened (straight black arrow,
A) with surrounding edema (curved white arrow, A) and
fat stranding (curved black arrow, A). Duodenum is dilated
proximal to intussusception, despite nasogastric decompression.
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Hypoproteinemia
Although the potential causes of hypoproteinemia are innumerable, it can
result from malnutrition, organ failure, and carcinoma. Edema results and
manifests as mild symmetric diffuse bowel mural and fold thickening, ascites,
and superficial soft-tissue stranding. Allowing large-field-of-view
soft-tissue evaluation, MRI small-bowel follow-through also provides an
opportunity to search for evidence of cirrhosis, renal failure, or
carcinomatosis, thus aiding in identifying a probable underlying cause (Fig.
4A,
4B).
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Fig. 4A —Axial MRI small-bowel follow-through in 40-year-old woman
with severe hypoproteinemia and peritoneal metastases of unknown primary.
Images show diffuse duodenal and jejunal mural and mucosal fold thickening
(straight white arrows), ascites (straight black arrows),
peritoneal carcinomatosis (curved black arrows), and subcutaneous
edema (curved white arrows).
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Fig. 4B —Axial MRI small-bowel follow-through in 40-year-old woman
with severe hypoproteinemia and peritoneal metastases of unknown primary.
Images show diffuse duodenal and jejunal mural and mucosal fold thickening
(straight white arrows), ascites (straight black arrows),
peritoneal carcinomatosis (curved black arrows), and subcutaneous
edema (curved white arrows).
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Small-Bowel Obstruction
Acute or chronic small-bowel obstruction or ileus can present with proximal
enteric luminal dilation, depending on the site, severity, and chronicity of
the obstruction. MRI small-bowel follow-through is often facilitated by
proximal loop dilation and a high intraluminal signal resulting from the
presence of fluid-filled loops on steady-state free-precession (SSFP) images,
even in the absence of sufficient contrast ingestion (not rare because of
preemptive patient fasting before surgical intervention or the presence of
emesis) (Fig. 5).
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Fig. 5 —50-year-old man with malnutrition and weight loss. Axial MRI
small-bowel follow-through shows diffuse duodenal (white arrow) and
jejunal (black arrow) dilation. Note increased distance between
attenuated mucosal folds. Laparoscopic evaluation confirmed chronic
small-bowel obstruction secondary to adhesions.
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Inflammatory Findings
Crohn's Disease
Crohn's disease may affect any enteric segment from the mouth to the
rectum; its manifestations most often include mucosal ulceration, mural
thickening, and stricture formation (Fig.
6). Characteristics of increased specificity for a diagnosis of
Crohn's disease include increased mesenteric vascularization, "creeping
fat" (an increased amount of mesenterial fat), skip lesions, and fistula
and abscess formation. These characteristics are depicted to greater effect on
MRI small-bowel follow-through than on projectional fluoroscopic studies,
during which overlapping loops of bowel may obscure fine details
[10].
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Fig. 6 —34-year-old woman with known Crohn's disease who presented
with nausea and vomiting. MRI small-bowel follow-through shows thickening
(white arrows) and ulceration (curved black arrows) of third
part of duodenum. Separation of small-bowel loops and increased mesenteric fat
(straight black arrow) are visualized. Interposed segments of
unaffected jejunum and ileum (i.e., skip lesions) are also seen.
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Celiac Disease
Although reversal of the fold pattern and transient intussusception are
typical of celiac disease in the jejunum and ileum, the duodenal findings may
be variable. Duodenal manifestations of celiac disease include focal mucosal
erosions, diffuse or nodular fold thickening
(Fig. 7), mural asymmetry, and
fold attenuation (Fig. 8). A
nonspecific mild luminal dilation or stricture may also be found
[10,
11]. An association with
intramural fat deposition has also recently been described
[12]. Adenocarcinoma and
lymphoma occur with increased frequency in patients with celiac disease and
are readily identifiable on MRI small-bowel follow-through.
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Fig. 7 —32-year-old man with malabsorption, steatorrhea, and weight
loss, who was subsequently confirmed on mucosal biopsy to have celiac disease.
Axial MRI small-bowel follow-through shows thickened duodenal folds
(arrows) and loss of jejunal fold detail, consistent with celiac
disease.
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Fig. 8 —70-year-old man with diet-resistant celiac disease. Duodenal
and jejunal dilation (black arrows), mucosal fold attenuation
(white arrowhead), and ulceration (white arrow) are readily
appreciated on MRI small-bowel follow-through. Findings are consistent with
ulcerative duodenitis and jejunitis due to celiac disease.
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Duodenitis
Duodenitis most commonly occurs as a result of peptic ulcer disease
exacerbated by Helicobacter pylori infection. Other causes include
medications such as nonsteroidal antiinflammatory drugs, viral infection, and
in flammatory conditions, most notably Crohn's disease and celiac sprue. MRI
small-bowel follow-through manifestations of duodenitis include mural
thickening secondary to edema, mucosal ulceration, and adjacent fat stranding
(Fig. 9A,
9B).
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Fig. 9A —60-year-old man with acute onset of severe epigastric pain.
MRI small-bowel follow-through shows diffuse mural and fold thickening
(black arrows), surrounding edema (straight white arrows),
and fat stranding (curved white arrow, B), consistent with
duodenitis.
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Fig. 9B —60-year-old man with acute onset of severe epigastric pain.
MRI small-bowel follow-through shows diffuse mural and fold thickening
(black arrows), surrounding edema (straight white arrows),
and fat stranding (curved white arrow, B), consistent with
duodenitis.
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Benign and Malignant Neoplastic Findings
Hyperplastic Polyps
Hyperplastic polyps are innocent outgrowths of the lining of the duodenum
and do not have any malignant potential. On MRI small-bowel follow-through,
these polyps manifest as pedunculated soft-tissue polyps adherent to the
duodenal wall (Fig. 10).
Differential considerations for such a detected lesion include Brunner's gland
hamartoma, gastric and pancreatic heterotopia, adenoma, adenocarcinoma,
gastrointestinal stromal tumor, lymphoma, and prolapsed gastric neoplasm. When
the lesions are multiple, one should consider Brunner's gland hyperplasia,
lymphoid hyperplasia, heterotopia, carcinoid, adenoma, polyposis syndrome, and
metastatic disease [13].
Lipoma
Duodenal lipoma is a benign mesenchymal tumor or benign fatty tumor.
Occurring most frequently in men in their seventh decade, these lesions tend
not to cause symptoms, although they may rarely lead to obstruction or
hemorrhage if ulceration occurs. As with lesions elsewhere, uncomplicated
duodenal lipomas have signal characteristics mirroring those of fat on all
sequences, with signal "drop-off" on fat-suppressed sequences
(Fig. 11A,
11B).
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Fig. 11A —79-year-old man with duodenal lipoma. MRI small-bowel
follow-through shows incidentally detected intraluminal duodenal lipoma
(arrows) of similar signal intensity to fat on steady-state free
precession image (A) and with signal loss on fat-saturated sequence
(B).
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Fig. 11B —79-year-old man with duodenal lipoma. MRI small-bowel
follow-through shows incidentally detected intraluminal duodenal lipoma
(arrows) of similar signal intensity to fat on steady-state free
precession image (A) and with signal loss on fat-saturated sequence
(B).
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Leiomyoma
Leiomyomas are benign neoplasms of the duodenum
[8]. Afflicted patients
frequently present with gastrointestinal bleeding due to ulceration, often in
the presence of abdominal pain. The MRI small-bowel follow-through appearances
of leiomyomas are varied and include polypoid intraluminal, submucosal, or
intramural soft-tissue masses. Leiomyomas may be intraluminal or exoenteric
(Fig. 12A,
12B).
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Fig. 12A —40-year-old man with epigastric pain. MRI small-bowel
follow-through shows large eccentric polypoid mass (straight black
arrows) partly obstructing descending portion of duodenum (white
arrows indicate proximal mild duodenal dilation), which was found at
histology to be a leiomyoma. Ulcerated proximal border (curved black
arrows) is well visualized.
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Fig. 12B —40-year-old man with epigastric pain. MRI small-bowel
follow-through shows large eccentric polypoid mass (straight black
arrows) partly obstructing descending portion of duodenum (white
arrows indicate proximal mild duodenal dilation), which was found at
histology to be a leiomyoma. Ulcerated proximal border (curved black
arrows) is well visualized.
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Adenoma
Duodenal adenomas appear as focal, usually solitary, intraluminal polypoid
lesions, 80% of which have a periampullary distribution
(Fig. 13). Histologic subtypes
include tubular, villous, and tubulovillous adenomas. Although villous
adenomas have malignant potential and require surgical resection, tubular
adenomas are typically resected for diagnostic and symptomatic purposes
[6,
8]. An increased incidence of
adenomas occurs with hereditary nonpolyposis colon carcinoma syndrome and
familial adenomatous polyposis.
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Fig. 13 —55-year-old man with suspected gallbladder mass and upper
abdominal discomfort. Polypoid periampullary lesion was incidentally detected
(arrow) and subsequently confirmed at histology to be tubular
adenoma.
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Adenocarcinoma
Adenocarcinomas are the most common malignant neoplasm of the small
intestine, with more than 60% occurring in the duodenum. Adenocarcinomas have
their peak prevalence in the fifth and sixth decades of life, when patients
present with gastrointestinal bleeding, jaundice, or obstruction
[6,
8]. On MRI small-bowel
follow-through, adenocarcinomas may appear as focal mural thickening
(Fig. 14), infiltrative
annular strictures, or polypoid intramural or intraluminal masses.
Differential considerations for such appearances include carcinoid,
gastrointestinal stromal tumor, lymphoma, metastatic disease, and rare
mesenchymal neoplasms such as neurofibroma and schwannoma
[13].
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Fig. 14 —50-year-old man with weight loss and upper abdominal
fullness. MRI small-bowel follow-through shows shouldered annular "apple
core" duodenal mass (white arrow) that was later confirmed to
be adenocarcinoma. Proximal duodenal luminal dilation (black arrow)
results.
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Lymphoma
Duodenal lymphoma may occur as a primary entity (Fig.
15A,
15B) or as a manifestation of
systemic disease (Fig. 16A,
16B). MRI features may include
marked symmetric or asymmetric concentric wall thickening, effacement or
thickening of mucosal folds, aneurysmal small-bowel loop dilation, and luminal
strictures. Paraenteric mesenteric fat stranding may be seen
[14].
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Fig. 15A —Coronal MRI small-bowel follow-through images of 85-year-old
woman with high-grade B-cell non-Hodgkin's lymphoma of duodenum. (Reprinted
with permission from Lohan DG, Alhajeri AN, Cronin CG, Roche CJ, Murphy JM. MR
enterography of small-bowel lymphoma: potential for suggestion of histologic
subtype and the presence of underlying celiac disease. AJR 2008;
190:287–293 [14])
Duodenal mural thickening, aneurismal dilation (white arrows), and
stranding of mesenteric fat planes (black arrow, A) were found
at MRI small-bowel follow-through. Because of aneurysm dilation, lymphoma was
thought to be more likely than adenocarcinoma.
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Fig. 15B —Coronal MRI small-bowel follow-through images of 85-year-old
woman with high-grade B-cell non-Hodgkin's lymphoma of duodenum. (Reprinted
with permission from Lohan DG, Alhajeri AN, Cronin CG, Roche CJ, Murphy JM. MR
enterography of small-bowel lymphoma: potential for suggestion of histologic
subtype and the presence of underlying celiac disease. AJR 2008;
190:287–293 [14])
Duodenal mural thickening, aneurismal dilation (white arrows), and
stranding of mesenteric fat planes (black arrow, A) were found
at MRI small-bowel follow-through. Because of aneurysm dilation, lymphoma was
thought to be more likely than adenocarcinoma.
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Fig. 16A —35-year-old man with stage IV non-Hodgkin's lymphoma. Axial
(A) and coronal (B) MRI small-bowel follow-through shows large
mesenteric mass compressing duodenum posteroinferiorly. In duodenum, folds are
thickened, nodular, and irregular because of lymphomatous involvement
(arrows).
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Fig. 16B —35-year-old man with stage IV non-Hodgkin's lymphoma. Axial
(A) and coronal (B) MRI small-bowel follow-through shows large
mesenteric mass compressing duodenum posteroinferiorly. In duodenum, folds are
thickened, nodular, and irregular because of lymphomatous involvement
(arrows).
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Carcinoid Tumor
Carcinoid tumors affecting the duodenum are uncommon. When present, they
occur in the proximal duodenum and manifest as solitary or multifocal
intraluminal polyps or intramural masses
(Fig. 17). In contrast to
jejunal or ileal carcinoid tumors, which are usually high-grade, duodenal
carcinoids are frequently low-grade tumors. Furthermore, duodenal carcinoid
tumors often lack the desmoplastic response considered typical of those
lesions that occur more distally in the small bowel
[13].
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Fig. 17 —Coronal MRI small-bowel follow-through true fast imaging with
steady-state precession (true FISP) in 61-year-old man with carcinoid tumor.
MR small-bowel follow-through shows irregular thickening of duodenal wall and
folds (arrows) that were confirmed at histology to contain tumor.
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Metastases
Metastases are the most common malignant process of the small bowel. Spread
may occur via hematogenous dissemination (e.g., melanoma, lung, breast, and
renal primary lesions) (Fig.
18A,
18B) or direct local invasion
(Fig. 19A,
19B). Hematogenous metastases
may have a variety of appearances, including single or multiple polyps, mural
soft-tissue masses, annular strictures, or cavitary masses.
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Fig. 18A —MRI small-bowel follow-through in 35-year-old man with
biopsy-proven melanoma metastatic to small bowel. On axial (A) and
coronal (B) images, eccentric mural soft-tissue mass (arrows)
results in considerable luminal distention, having appearance typical of
melanoma metastases.
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Fig. 18B —MRI small-bowel follow-through in 35-year-old man with
biopsy-proven melanoma metastatic to small bowel. On axial (A) and
coronal (B) images, eccentric mural soft-tissue mass (arrows)
results in considerable luminal distention, having appearance typical of
melanoma metastases.
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Fig. 19A —57-year-old man with metastatic abdominal neuroendocrine
tumor. Coronal (A) and axial (B) images from MRI small-bowel
follow-through show large left upper quadrant metastases (black
arrows, A). One of these metastases (white arrows) is
invading posterior aspect of fourth part of duodenum.
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View larger version (140K):
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Fig. 19B —57-year-old man with metastatic abdominal neuroendocrine
tumor. Coronal (A) and axial (B) images from MRI small-bowel
follow-through show large left upper quadrant metastases (black
arrows, A). One of these metastases (white arrows) is
invading posterior aspect of fourth part of duodenum.
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Conclusion
MRI small-bowel follow-through is a versatile technique that allows
confident endoluminal, mural, and extramural soft-tissue evaluation at high
contrast resolution. Although they are uncommon, lesions of the duodenum may
present a considerable diagnostic dilemma. Knowledge of their specific imaging
features may aid in suggesting a likely underlying cause.
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C. G. Cronin, D. G. Lohan, A. M. Browne, C. Roche, D. O'Keeffe, and J. M. Murphy
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Abstract
Introduction
