Golden rules for diagnosing intestinal malrotation

Dr/Ahmed Bahnassy

Consultant Radiologist

Riyadh Military Hospital

Malrotation..the ticking bomb

ANOMALIES of bowel rotation and

fixation, or malrotation, are a

common predisposing cause of volvulus

and obstruction in infancy and

Childhood.

Accurate diagnosis is vital to avoid the catastrophic consequences of midgut volvulus

Embryological basis-GIT journey

Malrotation and volvulus

Be alert

First, the initial passage of barium through the duodenum should be observed directly with fluoroscopy to confirm the course of the duodenum and the position of the duodenojejunal junction.

The duodenum often is obscured as the more distal loops of the small bowel fill with barium,

Be quick

Second, the position of the duodenojejunal

junction should be documented with the acquisition of both frontal and true lateral projections.

Be cautious

Third, the stomach should not be overfilled

with contrast.

This will cause downwards displacement of duodenojejunal flexure in lateral view making false positive diagnosis of malrotation.

Too much

Be active

• Fourth, manual palpation may be used during the upper GI study to determine the mobility of the duodenum

Be proactive

• Fifth, other imaging studies should be reviewed.Abnormal relation SMV/SMA in US should raise suspicion .

Be patient

Sixth, if the diagnosis remains in doubt or the upper GI tract findings are equivocal delayed abdominal radiographs should be

acquired to identify the position of the cecum.

The normal position of the duodenojejunal

junction is to the left of the left-sided pedicles of the vertebral body at the level of the duodenal bulb on frontal views and posterior (retroperitoneal) on lateral views.

Katz criteria..historical article very valuable in difficult cases

Measurement and meanings

line

point

Relative importance of signs

9 points Scoring

(a) location of the pylorus to the left of the spine,

(b) Location of the DJJ lower than the superior end plate of L-2,

(c) DJJ to the right of the left pedicle .

(d) cephalocaudal distance from the level of the apex of the duodenal bulb to the DJJ greater than 1.3 cm (adjusted for patient size by dividing the actual measurement

by a correction factor: the sum of the interpediculate distance at T-1 I and

distance between T-11 and T-12 superior

end plates divided by 2),

(e) the vertical portion of the sweep (from the bulb apex to the inferior flexure) longer than the

horizontal portion (from the inferior flexureto the DJJ), (f) length of the horizontal segment less than 2.6 cm

(adjusted for size by using the same correction factor),(g) obstruction of the horizontal segment,(h) jejunum located in the right upperquadrant, and (i) zigzag shape of the jejunum.

Survival guide in controversial cases

With this system, a single positive

finding is consistent with a normal variant

(score 0 or 1), the presence of two positive

findings is indeterminate (score 2), and the

presence of three is indicative of malrotation

(score 3).

Patterns of malrotation in upper GI80% of cases

• The third part of duodeum is retroperitoneal structure.

• This location excludes malrotation 100% as it is the ultimate proof of completion of embryonic journey of fetal GIT .

• Useful sign while doing upper GI ..in either way + or -.

Ultrasound localization of D3

In upper GI..anterior location of duodeum

Swirling sign..controversial significance but still worthy

Swirling SMV

anticlockwise

clockwise

• Abnormal caecal position is not a must in cases of malrotation and colon malrotation can be with normal DJ.

!

• Answer the surgeon question ..is there a midgut volvulus ?

With volvulus..notify urgently

Different appearances

corkscrew

block

Anterior d

Z shape

Malrotation without volvulus

• Beware of pitfalls and normal variants.

Wandering duodenum

Normal location of DJ flexure

Duodenum inversum

The duodenum descends then ascends to the right of the spine,before crossing horizontally to the left (small arrows). The duodenojejunal junction is at a normal location (large arrow)

Duodenal distorsion due to gastric overdistension

Small arrows indicate the course of the duodenum and proximal jejunum. The large arrow indicates the duodenojejunal junction projecting near the midline .After gastric decompression, the duodenojejunal junction was normal