View
221
Download
4
Category
Preview:
Citation preview
Protocol (Final)
Title
Conventional radiography and cross sectional imaging when planning dental implants in the anterior edentulous mandible to support an overdenture: a systematic review.
Details of Authors
Andrew Martyn Shelley University of Leeds, UK
Anne-Marie Glenny University of Manchester, UK
Michaela Goodwin University of Manchester, UK
Keith Horner University of Manchester, UK
Paul Brunton University of Leeds, UK
Corresponding author
Andrew Shelley
3 Yew Tree Park Road
Cheadle Hulme
Cheadle
Cheshire
SK8 7EP
United Kingdom
Telephone numbers
Home – 0161 485 3609
Place of work – 0161 320 4230
Fax – 0161 320 8134
e-mail - andrew@andrewshelley.com
Contents
1 Background.......................................................................................................................1
2 Review question................................................................................................................33 Inclusion criteria................................................................................................................4
4 Search Strategy................................................................................................................65 Study selection..................................................................................................................8
6 Data extraction................................................................................................................107 Quality assessment.........................................................................................................11
8 Data synthesis................................................................................................................129 Discussion.......................................................................................................................12
10 Dissemination..............................................................................................................1211 Appendices..................................................................................................................13
12 References..................................................................................................................20
i
1 Background
Implant supported overdentures in the edentulous anterior mandible are considered the
treatment of choice in many cases of severe or moderate alveolar resorption.1 For example,
the provision of two implants in the lower canine regions with stud attachments can be a
relatively simple way of addressing otherwise insoluble denture problems. The form of the
anterior mandible varies greatly according to the degree and pattern of resorption. This can
result in narrow, shallow or knife edge ridges which can complicate implant placement.2
Perforation of the lingual cortical plate during preparation for placement of dental implants
has the potential to cause severe bleeding and a life threatening upper airway obstruction. At
least 20 such case reports appear in the literature.3-20. Some authors have expressed the
opinion that preoperative cross sectional imaging is advisable, or should be routine, to
reduce the likelihood of such an event.2, 21, 22 Nonetheless, there is a responsibility to
maximise the diagnostic value of imaging whilst keeping radiation doses as low as
reasonably achievable.23 Cone beam CT is a significant improvement on multi-slice CT in
terms of radiation dose. Notwithstanding, whilst individual machines vary, cone beam CT
still has an effective dose around ten times that of, for example, a panoramic view.24 To
enable planning of dental implant therapy, an appreciation of the form of the anterior
mandible may also be gained through conventional radiography, preoperative palpation or
by peri-operative surgical exploration.2 It is unclear whether the preoperative availability of
cross sectional imaging would have an impact on the assessment, treatment or outcome in
such cases.
A hierarchy of levels of efficacy has been proposed for the evaluation of diagnostic
imaging.25-27 Fryback and Thornbury proposed six levels: technical efficacy, diagnostic
accuracy efficacy, diagnostic thinking efficacy, therapeutic efficacy, patient outcome efficacy
and societal efficacy.28 Many studies have been conducted to investigate technical efficacy
and diagnostic accuracy efficacy of cross sectional imaging methods and these have been
the subject of systematic review. 29-32 Nevertheless, the impact of cross sectional imaging on
assessment, treatment and outcome of dental implant therapy would be the subject of
evaluation at higher levels of efficacy. A scoping exercise revealed that there are far fewer
studies which evaluate the efficacy of diagnostic imaging at these higher levels and no
systematic reviews have been identified.
1
Guideline documents on selection criteria for imaging prior to implant placement have been
issued by several authorities.24, 33-36 Notwithstanding, guidelines on selection of images for
dental implantology are often non-specific, stated in vague terms and open to wide
interpretation. A previous study has demonstrated that the pattern of prescription of imaging
in such circumstances is chaotic.37 There is no agreement amongst implant practitioners in
the North West of England. The aim of this review is to help fill the gap in knowledge with
regard to the higher levels of efficacy of imaging methods prior to dental implant placement
in the edentulous anterior mandible and to inform guideline development.
2
2 Review question
1. Does the use of cross sectional imaging prior to dental implant placement in the
anterior edentulous mandible have any impact on diagnostic thinking, compared to
conventional imaging alone, when an implant retained overdenture is planned?
2. Does the use of cross sectional imaging prior to dental implant placement in the
anterior edentulous mandible have any impact on treatment planning, compared to
conventional imaging alone, when an implant retained overdenture is planned?
3. Does the use of cross sectional imaging prior to dental implant placement in the
anterior edentulous mandible have any impact on outcome, compared to
conventional imaging alone, when an implant retained overdenture is planned?
3
3 Inclusion criteria
PICOS elements
Participants/ Population
► Human
► In vivo or in vitro using radiographic phantoms
► Complete mandibular edentulism
► Implants are planned for the interforaminal region which will support a complete
lower overdenture.
► If insufficient studies are identified, then those which investigate dental implant
placement anywhere in the mouth, but including the anterior mandible, will be
included.
Interventions
► Cross sectional imaging, of all types, prior to dental implant placement.
Comparators
► Conventional two dimensional radiography prior to dental implant placement.
Outcomes
► Diagnostic thinking, therapeutic efficacy or patient outcome as defined by Fryback
and Thornbury 28: (See Appendix A) Studies which are concerned only with Fryback
and Thorbury’s lower levels, technical efficacy or diagnostic accuracy efficacy, will
not be included. Similarly, any studies which analyse only the higher level of societal
efficacy will not be included.
4
5
Study design
Studies will be included where the primary purpose is cross sectional imaging for
assessment prior to dental implant placement rather than being primarily for the construction
of a computer generated surgical guide.
The following study designs will be considered
► Before and after studies, controlled or uncontrolled
► Case control studies
► Cohort studies
► Randomised controlled studies
► Non randomised controlled studies
Language
Studies in the English language
Studies where there is an English language abstract and a translation of the full paper can
be identified.
Publication types
► Peer reviewed journals
► Non peer reviewed journals
► Reports
► Book chapters
► Conference abstracts
► Theses
► Informal reports and on-going studies
6
4 Search Strategy
Electronic search of databases
- A pilot study has been conducted and is presented separately. The conclusion
was that the following search terms should be used without date restriction.
(Dental Implant* OR Implant dentistry OR oral implant*) AND (Radiograph* OR Radiolog*
OR Tomograph* OR Imag*) AND (planning OR assessment) AND (compar* OR chang*)
-The following electronic databases will be searched:
o Pubmed
o Embase
o Cochrane CENTRAL library
Additional searches
Trial searches of the following sources are presented separately
► Reference trackingo Search reference sections of studies identified in the electronic search
o Search reference sections of published guideline documents
► Citation trackingo Citation tracking software
Web of Knowledge Science Citation Index
– see trial search in pilot study
► Hand searching
o Search contents pages from key journals identified in electronic search
– see trial search in pilot study
7
8
► Grey literatureo Hand search key conference proceedings. IADR website
– see trial search in pilot study
o Opengrey website
– see trial search in pilot study
o Trials register – www.clinicaltrials.gov www.who.int/trialsearch/
– see trial searches in pilot study
o Email requests to Departments of Dental Radiology in the UK?
o Systematic review website – canvas for unpublished studies
– see website www.andrewshelley.com/systematic_review.html
► Thesis searchingo Dissertation and Thesis data base search
Proquest
EThOS
Reporting
o Contemporaneous recording of all stages of the process and the results
9
5 Study selection
STAGE 1
AMS will review titles to exclude those studies which are clearly irrelevant to this systematic
review. This will be done by comparison of the titles with the inclusion criteria. Remaining
studies will pass to stage 2.
STAGE 2
AMS will review abstracts to identify relevant articles that will be retrieved for full text review
in Stage 3. This will be done by comparison of the studies with the inclusion criteria. Where
studies are clearly irrelevant no further documentation will be carried out. Where a study
narrowly fails to meet the inclusion criteria, the reason will be recorded. In cases where the
abstract provides insufficient detail the study will pass to stage 3 where the full text will be
examined.
In those cases where a study narrowly fails to meet the inclusion criteria, the decisions will
be re-examined by a second reviewer.
In practice, it is likely that stages 1 and 2 will be carried out simultaneously
STAGE 3
Where studies appear to meet the inclusion criteria, or where a decision cannot be made on
the title and abstract alone, full papers will be obtained for detailed assessment against the
inclusion criteria. At this stage, duplicate studies will be removed or, where studies are
published in multiple parts, individual papers will be combined. Where further information is
required, that is not included in a study report, authors will be contacted for clarification.
Stage 3 will be carried out independently by AMS and AMG. Where there is disagreement,
this will be resolved by consensus. Where consensus cannot be reached, a third reviewer,
KH, will be consulted.
10
Reviewers will not be blinded to authors, institution or study results during the study
selection process. This has been demonstrated to be of limited value whilst considerably
increasing the difficulty of the process of study selection.38, 39
A PRISMA flow diagram will be constructed to record the process of study selection.
(Preferred Reporting Items for Systematic Reviews and Meta-Analyses) See Appendix B
11
6 Data extraction
Data extraction from included studies will be carried out independently by AMS and one
other reviewer. This protocol has been demonstrated to result in fewer errors than data
extraction by a single reviewer.40 Study characteristics and outcome results will be collected
using a standardised form. (Appendix C) Any discrepancies will be resolved by discussion
and, where necessary, by involvement of a third reviewer.
The development of the data extraction form is the result of a pilot study which is reported
separately. The data extraction form has both a printed version and an electronic version in
Microsoft Excel. It is the intention to use the Excel form for more convenient manipulation
and analysis of data.
12
7 Quality assessment
The methodological quality of each study will be assessed using the tool developed by
Meads and Davenport for diagnostic before-after studies.41 This, in turn, is a modification of
The Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool developed by the
NHS centre for Reviews and Dissemination at the University of York, UK.42 The tool
appraises study quality by indicating the presence or absence of 12 key criteria through a
series of questions that are answered as ’yes’, ’no’, ’unclear’ or ‘not applicable’. In addition
there are two questions for which a subjective judgement of quality is made. For example,
Meads and Davenport added the question, “Who performed the clinical evaluation and
image analysis?” In a different systematic review protocol, concerning three dimensional
imaging, Josephson et al similarly modified QUADAS by adding a question about the level of
training of evaluators.43 Whilst the content is the same, the presentation of Meads’ and
Davenport’s tool has been adapted for this systematic review. This adaptation allows a
common visual interpretation of the results of all questions. The quality assessment tool is
presented in Appendix D.
Quality assessment will be carried out independently by AMS and one other reviewer.
Where there is disagreement, this will be resolved by consensus. Where consensus cannot
be reached, a third reviewer will be consulted.
A pilot study of the quality assessment tool has been carried out and is presented
separately.
13
8 Data synthesis
A narrative synthesis will be carried out under the following headings:
► Study characteristics
Study characteristics will be described by means of narrative and tabulation
► Core synthesis
Study results will be synthesised by tabulation using appropriate colour coding
► Exploratory synthesis
Relationships within the data will be explored and differences considered
A pilot study has been carried out using the studies identified in the rapid scoping exercise. This is presented separately.
9 DiscussionThe robustness of the synthesis will be explored together with a discussion of the strengths and weaknesses of the review.
10 Dissemination
The following dissemination strategy will be undertaken:
► Make the review accessible through publication in an academic journal.► Alert potentially interested parties to the existence of the review► Present findings at academic conferences where appropriate► Make details available on the systematic review website though subject to any
publication restrictions appropriate to academic publishing.
14
11 Appendices
15
Appendix ADiagnostic thinking, therapeutic efficacy or patient outcome as defined by Fryback and
Thornbury
Question 1Level 3. Diagnostic thinking efficacy 28
► Number of cases in a series in which image judged helpful to making the diagnosis
► Entropy change in differential diagnosis probability distribution
► Difference in clinicians’ subjectively estimated diagnosis probabilities pre to post test
information
► Empirical subjective log-likelihood ratio for test positive and negative in a case series
Question 2Level 4. Therapeutic efficacy 28
► Number of times image judged helpful in planning management of the patient in a
case series
► Percentage of times procedure avoided due to image information
► Number of times therapy planned pretest changed after image information was
obtained
► Number of times clinicians’ prospectively stated therapeutic choices changed after
test information
Question 3Level 5. Patient outcome efficacy 28
► Percentage of patients improved with test compared with without test
► Morbidity or procedures avoided after having image information
► Change in quality adjusted life expectancy
► Expected value of test information in quality adjusted life years (QALYs)
► Cost per QALY saved with image information
16
Appendix B PRISMA flow diagram
17
APPENDIX C – Data extraction form (printed version)
Data Extraction Form v2(Adapted from Albon et al.)
Where the required information is not stated in the study report write NS
Study detailsAuthor; year, trial name
Country(ies) and years of recruitment
Study design
Area of the mouth studied
Conventional imaging technique used
X sectional or 3D imaging technique used
Setting (practice, hospital etc)
Comments:
Patient characteristicsPopulation
Number of patients in study
Age (provide all information from study eg range, SD etc)Gender – state percentage male (%)
State presenting problem if not partial or complete edentulismInclusion/exclusion criteria
Comments:
18
Name of assessor
Evaluator characteristicsNumber of evaluators
Types of evaluator (surgeon, radiologist etc)
Comments:
InterventionsNumber of excluded patients
Number of patients after exclusions
Implant manufacturer(s)
Lengths and widths of implants available for selection
Number of implants placed
How many anterior mandible?
How many posterior mandible?
How many anterior maxilla?
How many posterior maxilla?
Did evaluators carry out a clinical examination?
If no clinical examination carried out, was other clinical information available to evaluators (eg. study casts, clinical findings etc)Comments:
19
Outcomes for analysis
What were the outcome measures?(complete the sections which apply below)
If outcome measure is simply selection of a different implantIn how many sites was a different implant selected after X sectional or 3D imaging evaluated?
If outcome specifies selection of a different length or widthIn how many sites was a different length of implant selected after X sectional or 3D imaging evaluated?In how many sites was a different width of implant selected after X sectional or 3D imaging evaluated?
If outcome specifies selection of a longer, shorter, wider or narrower implantIn how many sites was a longer implant chosen after X sectional or 3D imaging evaluated?
In how many sites was a shorter implant chosen after X sectional or 3D imaging evaluated?
In how many sites was a wider implant chosen after X sectional or 3D imaging evaluated?
In how many sites was a narrower implant chosen after X sectional or 3D imaging evaluated?
If outcome specifies prescription of additional procedures such as bone grafting, sinus lifting etc.
In how many sites was bone grafting prescribed after X sectional or 3D imaging but not after conventional imaging?In how many sites was bone augmentation prescribed after conventional imaging but not after X sectional or 3D imaging?In how many sites were other surgical procedures prescribed after conventional imaging but not after X sectional or 3D imaging?In how many sites were other surgical procedures prescribed after conventional imaging but not after X sectional or 3D imaging?
Comments:
Can outcome data for anterior mandible only be analysed?
20
Appendix D - Quality Assessment Tool (Modified from Quadas 1 by Meads & Davenport)
Author Year
Study title
No. Item N/A Yes Unclear No
1 Was the spectrum of patients representative of patients who will receive imaging in practice?
2 Were the selection criteria clearly described?
4Is the period between conventional imaging and 3D imaging short enough to be reasonably sure that the target condition did not change between the two tests?
5Did the whole sample or a random selection of the sample receive verification using a reference standard of diagnosis?(Yes for whole sample or random selection. No if neither.)
6Did the patients receive the same 3D imaging regardless of conventional imaging?
8Was the execution of the conventional imaging described in sufficient detail to permit replication of the test?
9Was the execution of the 3D imaging described in sufficient detail to permit its replication?
10Were the conventional imaging results interpreted without knowledge of the results of the 3D imaging?
11Were the 3D imaging results interpreted without knowledge of the conventional imaging?
12Were the same clinical results available when imaging results were interpreted as would be available when the imaging is used in practice?
13 Were uninterpretable/intermediate imaging results reported?
14 Were withdrawals from the study explained?
A Were patients recruited consecutively?
CWas the study and/or collection of clinical variables conducted prospectively?
BWhat was the explanation for patientswho did not receive 3D imaging?(Green for good quality, red for poor quality.)
DWho performed the clinical evaluationand image analysis?(Green for good quality, red for poor quality.)
Numbering is unchanged from original sources. Numbered items are from Quadas 1.Questions 3 & 7 were removed by Meads and DavenportLetters are additional questions from Meads and Davenport
Overall subjective quality assessment (Green for good quality, red for poor quality.)
21
12 References1. Thomason JM, Feine J, Exley C, Moynihan P, Muller F, Naert I et al. Mandibular two
implant-supported overdentures as the first choice standard of care for edentulous patients--the York Consensus Statement. Br Dent J 2009; 207:185-186.
2. Kalpidis CD,Setayesh RM. Hemorrhaging associated with endosseous implant placement in the anterior mandible: a review of the literature. Journal of Periodontology 2004; 75:631-645.
3. Pigadas N, Simoes P,Tuffin JR. Massive sublingual haematoma following osseo-integrated implant placement in the anterior mandible. British Dental Journal 2009; 206:67-68.
4. Del Castillo-Pardo de Vera JL, Lopez-Arcas Calleja JM,Burgueno-Garcia M. Hematoma of the floor of the mouth and airway obstruction during mandibular dental implant placement: a case report. Oral Maxillofac Surg 2008; 12:223-226.
5. Boyes-Varley JG,Lownie JF. Haematoma of the floor of the mouth following implant placement. SADJ 2002; 57:64-65.
6. Darriba MA,Mendonca-Caridad JJ. Profuse bleeding and life-threatening airway obstruction after placement of mandibular dental implants. J Oral Maxillofac Surg 1997; 55:1328-1330.
7. Flanagan D. Important arterial supply of the mandible, control of an arterial hemorrhage, and report of a hemorrhagic incident. J Oral Implantol 2003; 29:165-173.
8. Givol N, Chaushu G, Halamish-Shani T,Taicher S. Emergency tracheostomy following life-threatening hemorrhage in the floor of the mouth during immediate implant placement in the mandibular canine region. J Periodontol 2000; 71:1893-1895.
9. Isaacson TJ. Sublingual hematoma formation during immediate placement of mandibular endosseous implants. J Am Dent Assoc 2004; 135:168-172.
10. Kalpidis CD,Konstantinidis AB. Critical hemorrhage in the floor of the mouth during implant placement in the first mandibular premolar position: a case report. Implant Dent 2005; 14:117-124.
11. Krenkel C,Holzner K. [Lingual bone perforation as causal factor in a threatening hemorrhage of the mouth floor due to a single tooth implant in the canine region]. Quintessenz 1986; 37:1003-1008.
12. Laboda G. Life-threatening hemorrhage after placement of an endosseous implant: report of case. J Am Dent Assoc 1990; 121:599-600.
13. Mason ME, Triplett RG,Alfonso WF. Life-threatening hemorrhage from placement of a dental implant. J Oral Maxillofac Surg 1990; 48:201-204.
14. Mordenfeld A, Andersson L,Bergstrom B. Hemorrhage in the floor of the mouth during implant placement in the edentulous mandible: a case report. Int J Oral Maxillofac Implants 1997; 12:558-561.
15. Niamtu J, 3rd. Near-fatal airway obstruction after routine implant placement. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001; 92:597-600.
16. Panula K,Oikarinen K. Severe hemorrhage after implant surgery. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999; 87:2.
17. Ratschew C, Czernicky W,Watzek G. Lebensbedrochliche Blutung nach Implantation im Unterkiefer. Dtsch Zahnarztl Z 1994; 49:65-67.
18. ten Bruggenkate CM, Krekeler G, Kraaijenhagen HA, Foitzik C,Oosterbeek HS. Hemorrhage of the floor of the mouth resulting from lingual perforation during implant placement: a clinical report. Int J Oral Maxillofac Implants 1993; 8:329-334.
19. Weibrich G, Foitzik C,Kuffner H. [Life threatening oral hemorrhage after implantation into the distal right mandible]. Mund Kiefer Gesichtschir 2002; 6:442-445.
22
20. Woo BM, Al-Bustani S,Ueeck BA. Floor of mouth haemorrhage and life-threatening airway obstruction during immediate implant placement in the anterior mandible. Int J Oral Maxillofac Surg 2006; 35:961-964.
21. Hofschneider U, Tepper G, Gahleitner A,Ulm C. Assessment of the blood supply to the mental region for reduction of bleeding complications during implant surgery in the interforaminal region. Int J Oral Maxillofac Implants 1999; 14:379-383.
22. Longoni S, Sartori M, Braun M, Bravetti P, Lapi A, Baldoni M et al. Lingual vascular canals of the mandible: the risk of bleeding complications during implant procedures. Implant Dent 2007; 16:131-138.
23. European Commission. Radiation Protection 172. Evidence Based Guidelines on Cone Beam CT for Dental and Maxillofacial Radiolog. Luxembourg: Office for Official Publications of the European Communities, 2012
24. Harris D, Horner K, Gröndahl K, Jacobs R, Helmrot E, Benic GI et al. E.A.O. guidelines for the use of diagnostic imaging in implant dentistry 2011. A concensus workshop organised by the European Association for Osseointegration at the Medical University of Warsaw. Clin Oral Impl Res 2012; 00:1-11.
25. Fineberg HV, Bauman R,Sosman M. Computerized cranial tomography. Effect on diagnostic and therapeutic plans. JAMA : the journal of the American Medical Association 1977; 238:224-227.
26. Mackenzie R,Dixon AK. Measuring the effects of imaging: an evaluative framework. Clinical radiology 1995; 50:513-518.
27. Ramlaul A,Hogg P. Medical Imaging and Radiotherapy Research - Skills and Strategies. Edinburgh: Churchill Livingstone, 2010
28. Fryback DG,Thornbury JR. The efficacy of diagnostic imaging. Med Decis Making 1991; 11:88-94.
29. Brown AA, Scarfe WC, Scheetz JP, Silveira AM,Farman AG. Linear accuracy of cone beam CT derived 3D images. The Angle orthodontist 2009; 79:150-157.
30. Guerrero ME, Shahbazian M, Elsiena Bekkering G, Nackaerts O, Jacobs R,Horner K. The diagnostic efficacy of cone beam CT for impacted teeth and associated features: a systematic review. Journal of oral rehabilitation 2011; 38:208-216.
31. Haiter-Neto F, Wenzel A,Gotfredsen E. Diagnostic accuracy of cone beam computed tomography scans compared with intraoral image modalities for detection of caries lesions. Dento maxillo facial radiology 2008; 37:18-22.
32. Pinsky HM, Dyda S, Pinsky RW, Misch KA,Sarment DP. Accuracy of three-dimensional measurements using cone-beam CT. Dento maxillo facial radiology 2006; 35:410-416.
33. European Commission. Radiation Protection 136. European Guidelines on Radiation Protection in Dental Radiology. Luxembourg Office for Official Publications of the European Communities, 2004
34. FGDP(UK). Selection Criteria in Dental Radiography, 2nd edn: Faculty of General Dental Practitioners (UK) Royal College of Surgeons of England, 2004
35. American Dental Association. The Selection of Patients for Dental Radiographic Examinations. 2004;
36. Tyndall DA,Brooks SL. Selection criteria for dental implant site imaging: a position paper of the American Academy of Oral and Maxillofacial radiology. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2000; 89:630-637.
37. Shelley AM, Wardle L, Goodwin MA, Brunton P,Horner K. A questionnaire study to investigate custom and practice of imaging methods for the anterior region of the mandible prior to dental implant placement. Dentomaxillofac Radiol 2013; 42:20120179.
38. Berlin JA. Does blinding of readers affect the results of meta-analyses? University of Pennsylvania Meta-analysis Blinding Study Group. Lancet 1997; 350:185-186.
39. Haines T, Kennedy C, Gross A, Goldsmith C, Hondras M,Roving I: Influence of "blinding" on selection of articles for relevance [abstract]. In: 7th Cochrane Colloquium: Oct 5-9 1999; Rome, Italy.; 1999.
23
40. Buscemi N, Hartling L, Vandermeer B, Tjosvold L,Klassen TP. Single data extraction generated more errors than double data extraction in systematic reviews. Journal of clinical epidemiology 2006; 59:697-703.
41. Meads CA,Davenport CF. Quality assessment of diagnostic before-after studies: development of methodology in the context of a systematic review. BMC medical research methodology 2009; 9:3.
42. Whiting P, Rutjes AW, Reitsma JB, Bossuyt PM,Kleijnen J. The development of QUADAS: a tool for the quality assessment of studies of diagnostic accuracy included in systematic reviews. BMC medical research methodology 2003; 3:25.
43. Josephson CB, White PM, Krishnan A,Al-Shahi Salman A. Computed tomography angiography or magnetic resonance angiography for detection of intracranial vascular malformations in patients with intracerebral haemorrhage (Protocol). 2011;
24
Recommended