The role of imaging in the management of necrotising enterocolitis: a multispecialist survey and a review of the literature
The role of imaging in the management of necrotising enterocolitis: a multispecialist survey and a review of the literature
Margareta Ahle 0 1 2 3 4
Hans G. Ringertz 0 1 2 3 4
Erika Rubesova 0 1 2 3 4
0 Department of Radiology, Stanford University Medical Center , Stanford, CA 94305 , USA
1 Department of Radiology and Department of Medical and Health Sciences, Linköping University , 581 85 Linköping , Sweden
2 Margareta Ahle
3 Department of Radiology, Lucile Packard Children's Hospital, Stanford University Medical Center , Stanford, CA 94305 , USA
4 Division of Diagnostic Radiology, Department of Molecular Medicine and Surgery, Karolinska Institutet , Stockholm , Sweden
Objectives To investigate current practices and perceptions of imaging in necrotising enterocolitis (NEC) according to involved specialists, put them in the context of current literature, and identify needs for further investigation. Methods Two hundred two neonatologists, paediatric surgeons, and radiologists answered a web-based questionnaire about imaging in NEC at their hospitals. The results were descriptively analysed, using proportion estimates with 95% confidence intervals. Results There was over 90% agreement on the value of imaging for confirmation of the diagnosis, surveillance, and guidance in decisions on surgery as well as on abdominal radiography as the first-choice modality and the most important radiographic signs. More variation was observed regarding some indications for surgery and the use of some ultrasonographic signs. Fifty-eight per cent stated that ultrasound was used for NEC at their hospital. Examination frequency, often once daily or more but with considerable variations, and projections used in AR were usually decided individually rather than according to fixed schedules. Predicting the need of surgery was regarded more important than formal staging. Conclusion Despite great agreement on the purposes of imaging in NEC and the most important radiographic signs of the disease, there was considerable diversity in routines, especially regarding examination frequency and the use of ultrasound. Apart from continuing validation of ultrasound, important objectives for future studies include definition of the supplementary roles of both imaging modalities in relation to other diagnostic parameters and evaluation of various imaging routines in relation to timing of surgery, complications, and mortality rate. Key Points Imaging is an indispensable tool in the management of necrotising enterocolitis Predicting the need of surgery is regarded more important than formal staging There is great consensus on important signs of NEC on abdominal radiography There is more uncertainty regarding the role of ultrasound Individualised management is preferred over standardised diagnostic algorithms
Enterocolitis; necrotising; Abdominal radiography; Ultrasonography; Surveys and questionnaires; Professional practice
ANID Acquired neonatal intestinal disease
AR Abdominal radiography
CI Confidence interval
DAAS Duke abdominal assessment scale
GA Gestational age
NEC Necrotising enterocolitis
NIRS Near infra-red spectroscopy
PI Pneumatosis intestinalis
PVG Portal venous gas
SIP Spontaneous intestinal perforation
Necrotising enterocolitis (NEC), a potentially devastating
intestinal inflammation in neonates, has developed alongside
neonatal intensive care . With improving survival of the
most premature neonates , the epidemiological and
pathophysiological landscape keeps shifting [3, 4], and the need to
differentiate between NEC of different origins has been
pointed out [5–8]. Except for a general agreement that NEC should
be differentiated from spontaneous intestinal perforation (SIP)
[3, 5, 6, 9, 10], it is not settled whether to aim at a narrower
definition of NEC or a sub classification [6–8, 11]. Suggested
differential diagnoses include viral enteritis of infancy, feeding
intolerance of prematurity, cow milk’s protein allergy,
ischaem i c b o w e l d i s e a s e d u e t o c a r d i a c a n o m a l i e s , a n d
Hirschsprung’s disease [1, 5, 8]. Factors suggested to aid the
differential diagnosis are gestational age (GA), age at onset,
feeding volumes, clinical symptoms, stool cultures, blood
cultures, and some laboratory tests [1, 5, 12].
Subtle radiographic signs of early NEC may appear before
clinical signs and progress ahead of clinical deterioration, but
the hallmarks of NEC, pneumatosis intestinalis (PI), and
portal venous gas (PVG) are often transient, pneumoperitoneum
(PP) frequently missing in spite of intestinal perforation, and
the overall sensitivity of abdominal radiography (AR) low,
especially in extremely low birth weight infants [4, 9,
13–21]. Based on these insights, together with reports of
ultrasound (US) for early detection of PVG  and evaluation
of mesenteric circulation , a standardised algorithm for
early diagnosis and evaluation of progress was suggested in
1994. AR in two projections and US was recommended for
diagnosis in all cases, followed by repeated examinations at
4-6-h intervals, or at least daily, with supine and left lateral
decubitus films each time and repeated ultrasounds every 12
to 24 h . Details of radiographic patterns, analysed already
in 1979 to identify early signs of NEC , were later
systematised in the Duke Abdominal Assessment Scale
The staging system, referred to as Bell’s criteria [28, 29],
was originally designed as an aid for therapeutic decisions but
is widely used to define confirmed NEC as opposed to
suspected NEC. Gordon’s suggestions for differentiation
between NEC of different origins and other acquired neonatal
intestinal diseases (ANIDs) are sometimes referred to as
BGordon’s classification^ [5, 20].
Surgical intervention may be considered in deterioration
despite medical treatment, indicating intestinal perforation or
gangrene [30–33]. Fotter and Sorantin suggested that
radiographic and ultrasonographic indications should be Bfree
intraperitoneal gas, free intraperitoneal fluid, and diminished
bowel gas with asymmetric loops and persistent dilated loops
on at least two follow-up studies^ . Of these, only PP on
AR is generally accepted [34, 35], but, because of its low
sensitivity [9, 13, 36], other signs, such as a persistent/fixed
loop are still under discussion [30–32, 37, 38]. PVG on AR
has been associated with poor outcome and need for surgery
[37–40], mediated by the severity of NEC .
In contrast, early reports described PVG on ultrasound as
an early sign of NEC [22, 42–44]. Although US was found to
be valuable in differentiating NEC and SIP , other studies
failed to confirm the high sensitivity [45–47] but showed high
specificity of most sonographic findings [46, 47]. Doppler
studies may show decreased as well as increased mesenteric
flow velocities in connection with NEC [48–53].
Complex ascites (focal or echoic fluid) is associated with
intestinal gangrene, perforation, the need for surgery, and
otherwise poor outcome [16, 19, 37, 54, 55], absent perfusion
with bowel necrosis [33, 35], and the finding of a dilated,
elongated intestinal loop on AR , which is in turn
associated with poor outcome [37, 57]. PP detected with ultrasound,
as well as various combinations of ultrasonographic signs,
may also predict a poor outcome .
Despite decades of research, however, the optimal use of
imaging in NEC is still unclear. The purpose of this study was
to investigate current practices and perceptions regarding
imaging in the management of NEC, as described by involved
specialists, put them in relation to current literature, and
identify issues in need of further discussion.
Materials and methods
Guided by literature studies, summarised above, interviews
with neonatologists and paediatric surgeons, and a pilot
survey among paediatric radiologists, a web-based questionnaire
on the management of NEC was created in two versions, one
for neonatologists and paediatric surgeons and one for
radiologists (Appendix 1 and 2). Late complications were not
addressed. Links to the questionnaires were distributed by e-mail
through European and American specialist organisations for
neonatology, paediatric surgery, and paediatric radiology. To
increase the number of respondents, passing the links on
through personal communication was also accepted.
Two hundred two respondents, 77 neonatologists, 58
paediatric surgeons, and 74 radiologists answered between
October 2014 and September 2015. Seven held double
specialties in neonatology and paediatric surgery. Nine were
general radiologists, of whom five were also specialised in
paediatric radiology. To describe areas of agreement and diversity
within this multispecialist group as a whole, the results were
analysed with proportion estimation with 95% confidence
intervals (CI). Differences between specialities were also noted
and regarded as significant if the CIs did not overlap. In these
cases, p values were obtained by chi2 tests, and analyses were
repeated without the dominant groups of radiologists from the
Americas (n = 48) and neonatologists from the British islands
(n = 30), attempting to discern whether the differences were
more likely due to geographical variations in clinical traditions
or diverging perceptions between specialties. The results of
such supplementary analyses are provided in the text.
Details of distribution between countries and specialties are
given in supplementary table S1.
Paralytic ileus in sepsis was regarded the most important
differential diagnosis, closely followed by SIP. There were some
significant differences between specialties in the invariable
consideration of certain diagnoses. See Table 1.
The most important aspects, influencing the differential
diagnosis, were the clinical picture, radiographic findings
(clinicians only), degree of prematurity, and age at onset; see
supplementary table S2.
A total of 75%, 51% (40-63%) of radiologists and 88%
(81-93%) of clinicians (CI within brackets), p < 0.001, reported
that they always used some classification of NEC and 15%
(8-25%) of radiologists and 1.6% (0.3-6%) of clinicians that
they never do, p < 0.001. An assessment of Bsuspected^,
Bdefinite medical^, or Bsurgical^ NEC was used, at least
sometimes, by 88 %, variants of Bell’s criteria by 59 %, and Gordon’s
classification by 8 %. The differences were independent of the
geographical locations of the hospitals.
The DAAS, mentioned in three free comments, was not
included among the response alternatives since it is a system
for evaluation of AR rather than a NEC classification.
Use of imaging
The most common use of imaging was for confirmation of the
diagnosis. According to significantly more neonatologists
than radiologists, imaging was always used for this purpose
(Fig. 1). The difference was not explained by geographical
differences, which, in contrast, seemed to influence the use
of imaging before resuming feeding.
The choice of modality was most often made by clinicians,
but radiologists frequently reported that they were involved in
the decision, and, according to 65 % of all of them,
radiologists and clinicians decided by consent at least sometimes.
There was geographical variation in this respect, most likely
reflecting differences in clinical tradition.
Use of abdominal radiography
AR was the modality most widely used as first choice,
Balways^ stated by 92 % and Bsometimes^ by another 7 %;
see supplementary fig. S1. The use of projections is
summarised in Fig. 2. AR with a vertical beam was commonly
used in all patients with suspected NEC, but for the horizontal
beam, there was no uniform routine and no clear-cut
preference for the supine or left decubitus position.
Ninety-one per cent (82-96%) of neonatologists and 83%
(70-91%) of paediatric surgeons stated that they always read
AR by themselves, whereas only 18% (10-28%) of
radiologists did so, p < 0.001.
The reported importance of the findings on AR are
summarised in Table 2. The last column contains the
corresponding DAAS score. The findings considered most
important were PP and PI, followed by PVG and Bfixed loop^ on
Use of ultrasound
Fifty-eight per cent without significant differences between
specialties or regions stated that ultrasound was used for
NEC at their hospital. Ninety-three per cent of these would,
at least sometimes, combine AR and US, and 52% might
sometimes use US as first choice. The most common use of
US was in patients with inconclusive AR, especially in severe
cases with suspected but not verified perforation (Fig. 3).
Opinions about US regarding usefulness, availability, time
consumption, and inconvenience for the patient were more
diverse than the understanding of findings in AR, the general
perception being more positive among respondents from
hospitals where ultrasound is used for NEC, with differences
between specialties concerning time consumption. Details
are given in Table 3.
The most frequently evaluated signs on ultrasound were
focal fluid collections, PVG, echoic fluid, and thickening of
the intestinal wall. Details are given in Table 4.
Fourteen per cent of neonatologists stated that all clinicians
at their department do abdominal US and 32% that some do.
Where at least some clinicians performed US, 47% had
support from the radiology department in the evaluation of the
results—pictures (18%), cine loops (12%), or both (18%).
Fifty-one per cent (40-63%) of radiologists, compared to
20% (14-28%) of clinicians, rejected the idea that clinicians
who do not do ultrasound should learn it, p < 0.001.
There was considerable variation in examination frequency;
see Fig. 4.
Fig. 1. Use of imaging.
Percentages refer to proportions
of the total number of 202
respondents. Where significant
differences were detected,
percentages for the subgroups of
77 neonatologists, 58 paediatric
surgeons, and 74 radiologists are
presented with 95% confidence
intervals within brackets. For the
invariable use of imaging for
confirmation of the diagnosis, p =
0.002, and before resuming
feedings, p = 0.001.
Supplementary analyses showed
no influence of geographical
differences on the use of imaging
for confirmation of the diagnosis
but on the use of imaging before
Percentages refer to the proportions of respondents. Where significant differences between specialties were detected, 95% confidence intervals and
p values are given. Supplementary analyses showed no substantial influence of geographical variations
Other suggested differential diagnoses: tympanism due to CPAP (3); hypoperfusion/circulatory insufficiency, e.g. due to congenital heart disease (2);
immature gastrointestinal motility (2); paralytic ileus due to other causes than sepsis (metabolic, hypokalaemia, hypothyroidism, narcotics ) (3);
incarcerated hernia (1); obstipation (1); eosinophilic proctocolitis (1). Cow milk protein allergy was stated in free text by one radiologist
The frequency was usually decided individually, but 61%
sometimes used a fixed schedule, and 10% always did.
Sixty-three per cent stated that radiation might be a concern.
Whether NEC was confirmed or not, around 90 % would at
least sometimes use the same modality for repeated imaging.
See supplementary Table S3.
Indications for surgery
PP on AR was regarded an indication for surgery, at least
sometimes, by 99% and clinical deterioration despite medical
treatment by 96% of clinicians; see Table 5.
What is the role of imaging in NEC management and what should it be?
This was an open question to obtain a perception of our
respondents’ expectations from imaging in the current
management of NEC and a desirable development. One
vision expressed was that imaging should be
non-invasive, easy to perform, and easily repeatable, another that
it should be bedside. Radiologists as well as clinicians
repeated the importance of imaging in the management
of NEC, some stressing its importance in surveillance
over diagnosis, a few its role in the differential diagnosis.
Identification of late complications was mentioned.
Especially clinicians, but also a few radiologists, pointed
out that imaging should always be used, interpreted, and
planned in the context of clinical evaluation, and some
highlighted the importance of close interaction among
radiologists, neonatologists, and paediatric surgeons in this
regard. There were also critical remarks about excessive
use of X-rays. Around 30 per cent of comments, from
radiologists and clinicians alike, referred to the use of
US. Remarks about an observed or desired increase in
its use for NEC were more common than statements that
it would not add much to AR. Another frequent comment
was that ultrasound should be used for problem solving
rather than routinely, but the use of ultrasound for
monitoring was also suggested. Some radiologists pointed out
the lack of resources as an obstacle to using US, and some
clinicians noted the need for more scientific validation of
the method. Different traditions and opinions regarding
ultrasound in the hands of clinicians shine through in
Pneumatosis intestinalis/intramural gas
Portal venous gas
Persistent loop on sequential radiographs
Pattern of gas distribution
Separation of intestinal loops
Importance n [%]
a) Duke Abdominal Assessment Scale 
Percentages refer to the proportions of all 202 respondents. No significant differences between subgroups were
Findings suggested in free text: Bgrey abdomen^ (1), ascites (2), and thickened bowel wall (1). The first may
correspond to featureless or multiple separated bowel loops, i.e. 5p on the DAAS, the latter two to separation of
Thanks to easy distribution of web-based questionnaires, this
survey collected many respondents , evenly distributed
between specialties but, unfortunately, with uneven geographical
distribution within specialties, partly impairing a reliable
distinction between influences of specialty and regional variation
on the responses. With the open invitation, the real reach of the
survey could not be estimated and no response rate could be
calculated. The respondents thus represent primarily
significant differences between specialties were found, 95% confidence
intervals are given within brackets, p < 0.001. The difference was levelled
out when American radiologists were excluded, indicating that it was
conditioned by geographical variations in clinical traditions rather than
diverging perceptions between specialties
themselves: 202 professionals, enough involved in the
management of NEC to be reached by the questionnaire
and respond to it. Consensus can be expected to be
greater in this group than among unselected
neonatologists, paediatric surgeons, and radiologists, which is
possibly further enhanced by accepting a minor
contribution of questionnaires distributed by personal
communication. The special interest may explain the almost
60% reported use of US in NEC. Keeping the selection
of respondents in mind, however, the responses should
Comments about ultrasound were: Bpainful^ (1); Bhas not been done at my institution/no experience/US is not
used as a routine imaging modality in our hospital/department^ (3); Bit is not always possible at 24 hours^ (1);
Bdepends strongly on experience of the operator^ (1); Bneed more training for sonographers and radiologists in US
for NEC^ (1); Bnot really available in our unit—would like it to be^ (1); Bnot yet used as experience in detecting
pneumatosis, etc., is lacking, except for general assessment^ (1); Bdoing US in NEC for 15 years^ (1); Bwe use it
very frequently already—as often as needed^ (1); Bvery useful and valid in experienced hands^ (1)
Ultrasound in NEC…
…is readily available
Signs looked for with ultrasound, n = 118
Evaluated by a n [%]
a) Percentages refer to respondents from hospitals where ultrasound is done for NEC, n = 118 respondents: 41
neonatologists, 41 paediatric surgeons, and 42 radiologists. Six held double specialties in neonatology and
paediatric surgery. No significant differences between specialties were observed. b) Adverse outcome such as
need for surgical intervention or death, associations as reported in the literature. References within square brackets
A. Independently associated with adverse outcome
B. Associated with adverse outcome if present together with other signs
As for intestinal motility and bowel wall perfusion, reported associations refer to reduced motility and absent
Signs stated in free text were echogenicity of the intestinal wall, bowel motility, amount and location of fluid
collections, and Bzebra sign^, all of which are thought to be covered by the response alternatives above
be useful as a base for discussion about desirable
studies and future guidelines.
Despite decades of efforts to improve diagnostic accuracy
in NEC, there is no generally accepted routine, and the role of
imaging in relation to new methods of surveillance has not
The usefulness of imaging for confirmation of the
diagnosis, decisions on surgery, and surveillance is uncontroversial
among the respondents to this survey. Imaging before
resuming feeding seems to be an established practice at some
The findings almost unanimously perceived as most
important on AR correspond well to the upper scores of the DAAS
The lack of a standardised diagnostic algorithm may
correspond to the broad spectrum of different
presentations and courses of NEC. The suggested frequency of
AR every 6th hour to avoid delay of adequate treatment
Fig. 4. Examination frequency.
For each of three suggested
frequencies, Bmore than once
every 24 h^, Babout every 24 h^,
and Bless than every 24 h^,
respondents could choose
response alternatives Boften^,
Bsometimes^, or Brarely^. The
diagram summarises the
distribution of response
combinations among all 202
Ninety-five per cent confidence intervals and p values are specified where there were significant differences between modalities or respondents with and
without experience of US in NEC
a) A significantly greater proportion of surgeons than radiologists regarded portal venous gas on ultrasound as Bsometimes^ an indication for surgery:
52% (39-65%) vs. 26% (17-37%), p = 0.002. Summarising all positive responses (always and sometimes), the difference was significant between PVG
on AR, 65% (58-72%), and on US 50% (43-57%), p = 0.003
b) A significantly greater proportion of radiologists than surgeons rejected persistent loop as an indication for surgery: 31% (21-43%) vs. 7% (3-17%), p =
0.001. Supplementary analyses showed no substantial influence of geographical variations
c) A significantly greater proportion of neonatologists than radiologists rejected turbid or localised fluid as an indication for surgery: 36% (26-48%) vs.
9% (4-19%), p < 0.001. There was no substantial influence of the geographical locations of the hospitals of the respondents
d) Included in the clinicians' questionnaire only
e) PP on AR compared to PP on US
f) Where ultrasound was known to be used in NEC compared to where it was not
was motivated by the transient nature of radiographic
signs, sometimes preceding clinical deterioration.
Although proposed in 1994 , US is rarely used as
a part of the routine work-up but rather for gathering
more information when AR is inconclusive. Suggested
applications are early detection of PVG, evaluation of
fluid in the abdominal cavity, and assessment of bowel
wall perfusion , of which the former two are
frequently used according to our respondents. US for NEC
surveillance, as suggested by some respondents, was
less common, despite the absence of radiation and
possible high sensitivity of some ultrasonographic signs for
the need of surgery [16, 19, 33, 35, 54, 57].
Concern about radiation was an issue of low
agreement among our respondents. Scott et al. found a risk
of total radiation exposure exceeding a preferred limit of
1 mSv in infants in neonatal intensive care .
Whether the use of US lowers the frequency of AR
cannot be discerned from our results. Studies
investigating the impact of imaging frequency and choice of
modality for surveillance on parameters such as timing of
surgical intervention and complication rates would be
helpful to minimise radiation while maintaining the best
For the differential diagnosis, 75% of responding clinicians
would attribute at least some importance to US—a greater
proportion than have access to it. Nevertheless, 22% stated
that it would be of no importance at all. The value and
reliability of ultrasound in NEC remains controversial, but among
respondents with experience of US in NEC attitudes seem
Although most survey respondents thought that US
would, at least sometimes, be useful, the often repeated
objections of availability and operator dependency 
were expressed, as were concerns about the validity of
ultrasonographic findings. As for operator dependency,
the importance of good technique obtaining the pictures
and the interobserver variability at interpretation of AR
should not be ignored [21, 61, 62]. Saving pictures,
especially cine loops, together with a systematic
approach enables re-evaluation of ultrasonographic
examinations and may reduce operator dependency.
Validation studies are difficult to design because of
the Black of a robust gold standard^  apart from
findings at surgery or autopsy. This problem applies
also to AR, which, however, is more established in
the clinical tradition. Many recent studies use outcome
as reference standard, concentrating on the role of
imaging for monitoring and decision on surgery. This role,
which goes well with the priority of our respondents to
distinguish NEC that needs surgery from less serious
NEC and NEC-like conditions, may increase if infants
at high risk of developing surgical NEC are identified to
a greater extent by biomarkers or near-infrared
spectroscopy (NIRS) [34, 63].
In the differential diagnosis, the clinical picture was almost
unanimously regarded as the most important aspect, and it is
well known that suspected NEC patients are usually treated
for NEC, regardless of any formal criteria for diagnosis and
staging, and may even be operated on if their clinical state is
severe enough [9, 24, 41, 64, 65].
The decision on surgery is a balancing act between
early intervention to prevent progression of disease and
avoidance of unnecessary surgery, with considerable
variation in the readiness to intervene. One respondent
commented that many babies tolerate a
pneumoperitoneum very well, but the opinion that surgical management
becomes necessary in persistent PI at 48 h was also
expressed. Even if imaging is perceived to be important
for confirming the diagnosis, its most important role
may be for the timing of surgery, and reported results
on the potential of US to bridge the lack of sensitivity
of AR for intestinal perforation and bowel necrosis are
promising [33, 54, 56, 57].
The ability of US to detect smaller amounts of
intraperitoneal gas, presumably from contained or self-limiting
perforations, may partly explain that respondents perceived PP
differently when detected with US than on AR. In contrast,
complex ascites is also indicative of perforation and could be
expected to prompt surgery more often than reported.
Experience of ultrasound in NEC seems to influence the
evaluation of US signs.
The distribution of opinions on persistent loop on
sequential radiographs and portal venous gas on AR as indications
for surgery is similar to the equivocal results in the literature
Regarding surgery, PVG was evaluated similarly on
AR and US, in contrast to the concept of PVG on US
as an early sign of NEC. The latter may rely on an
over-interpretation of the first reports [22, 42–44] or be
influenced by altered compositions of the patient
population, extremely premature infants being less likely to
present with PI and PVG [41, 46, 66]. In 15 infants
reported in 1986, mean GA was 33 weeks  compared
to 26 weeks median GA for 25 patients reported 30 years
Differences between specialties must be interpreted
with care, since, even where supplementary analyses
did not reveal any substantial regional influence,
practices may vary between hospitals within the same
region, and most respondents did not work at the same
hospital. Perspectives on the differential diagnosis
varying according to field of expertise could be expected.
How time consumption of ultrasound is perceived may
depend on whether it is compared to other clinical
bedside examinations or to obtaining an AR.
Clinicians evaluating radiographic images, or doing
ultrasound, do not eliminate the need for radiological
expertise but might contribute to a deeper understanding
of the results and facilitate the close interaction between
involved specialists, called for by some respondents.
Radiologists need to get clinically involved, be aware
of the consequences of reported signs, and discuss their
implications with clinicians. Understanding the
influence of the pathophysiological dynamic of NEC and
its variation with gestational age on radiographic and
ultrasonographic findings is important to tailor imaging
according to the needs of the individual patient. The
choice of modality as well as the examination schedule
should ideally be decided by consent. US and Doppler
may, however, confidently be recommended, at least for
evaluation of the need for surgery.
Together with the clinical picture, imaging is an
indispensable tool in the management of NEC: for detecting
complications where the diagnosis is already established
and solving the diagnostic puzzle where it is not. This
survey shows great agreement on the most important
signs of NEC on AR and their significance, with more
than 90% agreement independent of specialty, but
considerable diversity in imaging routines. Individualised
management is preferred over standardised algorithms. For
US, there is more variability in perceptions, partly
depending on the respondents’ experience of US in NEC.
Apart from further validation of ultrasound in the various
stages of NEC, future studies should seek to define the
supplementary roles of both imaging modalities in
relation to other diagnostic parameters such as biomarkers
and NIRS and to evaluate imaging routines in relation to
timing of necessary interventions, occurrence of
complications, and mortality rate. Future guidelines should
probably focus on evidence-based support for individualised
decisions rather than uniform protocols to fit all.
Funding The authors state that this work has not received any funding.
Compliance with ethical standards
The scientific guarantor of this publication is Hans Ringertz.
Conflict of interest The authors of this manuscript declare no
relationships with any companies, whose products or services may be related to
the subject matter of the article.
Statistics and biometry
for this paper.
No complex statistical methods were necessary
Informed consent Written informed consent was not required for this
study because it did not involve human subjects
Ethical approval Institutional Review Board approval was not required
because the study did not involve patients.
based on a multispecialty survey
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