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MINISTRY OF EDUCATION AND TRAINING MINISTRY OF DEFENSE INSTITUTE OF CLINICAL MEDICAL SCIENCE 108 TONG THI THU HANG RESEARCH ON IMAGING CHARACTERISTICS AND VALUE OF COMPUTED TOMOGRAPHY MYELOGRAPHY IN T[.]

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TONG THI THU HANG

RESEARCH ON IMAGING CHARACTERISTICS AND VALUE OF COMPUTED TOMOGRAPHY MYELOGRAPHY IN THE DIAGNOSIS OF TRAUMATIC BRACHIAL PLEXUS INJURY

Specialisation: Image Diagnostics Code: 62720166

SUMMARY OF DOCTORAL THESIS

HANOI – 2022

INSTITUTE OF CLINICAL MEDICAL SCIENCE 108

Supervisors:

1 Lam Khanh, Associate Professor, Doctor

2 Le Van Doan, Associate Professor, Doctor

The Thesis can be found at:

1 Vietnam National Library

2 Institute of Clinical Medical Science 108 Library

INTRODUCTION

Brachial plexus injury is commonly caused by trauma, mainly traffic accidents, leading to paralysis, and total or partial loss of sensation in the upper extremities

Imaging methods include X-ray, ultrasound, computed tomography (CT) myelography and magnetic resonance imaging (MRI) Which, CT myelography and MRI is commonly used because

CT myelography has a high value in diagnosing root avulsion which

is the most common type and MRI can diagnose all types of branchial plexus lesions

MRI has many advantages, however, it cannot be performed in patients with fixation hardware and difficult to diagnose incomplete root avulsion CT myelography overcomes the above disadvantages

At the Military Central Hospital 108, CT myelography and MRI for diagnosing branchial plexus lesions are applied Up to now, there has been no study on the value of CT myelography That's why we conduct the study “research on imaging characteristics and value of computed tomography in the diagnosis of traumatic brachial plexus injury” with 2 objects:

1 Imaging characteristics of CT myelography in the diagnosis of traumatic brachial plexus avulsion

2 Value of CT myelography in the diagnosis of traumatic brachial plexus avulsion

Dissertation novelty: The study is the first one in Vietnam to apply

CT myelography in the evaluation of traumatic brachial plexus injury

Contribution to Image Diagnostics: A new diagnostic

technique is developed

Contribution to Treatment: The study assesses systematic

brachial plexus injury and simultaneously indicates the correlation between clinic and image diagnostics, thus assisting clinical practitioners in the determination of an appropriate treatment policy

to recover effectively the patients’ functions

Thesis structure

The dissertation consists of 126 pages: Question 2 pages, overview 38 pages; Subject and methodology 18 pages; Results 27 pages; Comment 38 pages; Conclusion 2 pages; Limitation: 1; The thesis consists of 26 tables, 20 graphs, and 111 references

Chapter 1 OVERVIEW

1.1 Role of CT myelography in the diagnosis of traumatic

brachial plexus avulsion

CT myelography is a method of taking cervical spinal cord CT with contrast injection into the spinal canal, based on the principle that the contrast agent in the spinal canal increases contrast with the nerve roots less dense, from which to diagnose root avulsion

This method was first applied in 1986 by Marshall and De Silva, but the accurate diagnosis rate is not different from the X-ray myelography The development of generations of multi-sequential

CT scanners and software for image reconstruction and image noise reduction were helping cervical CT myelography and have made it highly valuable in diagnosing traumatic nerve root avulsion, especially being superior compared with MRI in incomplete root avulsion

Classification of root avulsion on CT myelography based on the classification of Nagano (1989) includes N: Normal roots; A1: Minor abnormality in the sleeve or root exit site; A2: Sleeve amputation, root deformity; A3: Sleeve amputation and no roots or rootlets observed; D: Missing the sleeve of the root; M: Pseudomeningocele

1.2 The application of CT myelography in the diagnosis of traumatic brachial plexus lesions in the world and Vietnam

In the world, since the advent of CT myelography, there have been studies comparing the value of this method with standard X-ray myelography, concluding that the method is not superior to standard X-ray myelography in diagnosing root avulsion lesions Further studies on the generations of multi- rows CT combined with multi-plane images, the research directions focus on comparing the value of

CT myelography with standard X-ray myelography and MRI Several studies compare the diagnostic value of CT myelography on different planes Conclusions mostly confirm the value of the method in diagnosing root avulsion lesions as superior to other methods, especially in incomplete root avulsion with high sensitivity, specificity and accuracy rate

In Vietnam, CT myelography has been performed only at 108 Military Central Hospital since 2015 in the diagnosis of a traumatic root avulsion 108 Central Military Hospital is a surgical facility for microsurgery for nerve grafting to treat traumatic nerve lesions, the need for diagnosis and treatment for patients with branchial plexus lesions is high, especially for those who can’t perform MRI or patients who have performed MRI but the results are not clinically relevant, it is necessary to conduct a cervical CT myelography to diagnose root avulsion lesions So far, we have had several reports on the value of this method in domestic journals

Chapter 2

OBJECTIVES AND METHODS

2.1 Research subjects and methods

The study was conducted on 179 patients who have scanned CT myelography at the Department of Radiology and undergoing surgery

at the Institute of Trauma and Orthopedics of 108 Military Central Hospital from May 2015 to May 2020

2.1.1 Standard selection

- Patients with a history of trauma, were clinically diagnosed with brachial plexus lesion, suspected of having root avulsion lesion, underwent CT myelography and underwent surgery at the Institute of Trauma and Orthopedics, 108 Central Military Hospital

- There are medical records, CT scans, surgical reports on the postoperative diagnosis of brachial plexus lesions, surgical method with nerve transfer to restore brachial plexus, and detailed descriptions of brachial plexus lesions according to the research patient record

2.1.2 Exclusion criteria

- Patients having traumatic brain injury or traumatic spinal cord injury associated with traumatic brachial plexus injury lead to falsification of the clinical signs of brachial plexus lesions

- Cases of brachial plexus injury due to obstetric trauma in neonates

- Patients who do have not full medical records or lose images, and research materials

2.1.3 Sample size

Convenient sample size, taking all patients who meet the selection criteria for the study (not less than 100 patients) The study was conducted on 179 patients

- Brivo 16 rows CT Scan (GE- United States) at the department

of radiology, 108 Military hospital

- Contrast agent Omnipaque 300 mg/ml

- Sterile instrument tray and 22G lumbar puncture needle

- Plexygon nerve stimulator (Vygon-Italy)

2.2.3 CT myelography procedure

The patient was fully explained about the imaging procedure, taking a full medical history, allergies, assessing the spinal status and lumbar puncture site, excluding contraindications (cerebrospinal infections, increased intracranial pressure)

The imaging procedure includes steps: lumbar puncture, injection of Omnipaque contrast agent 300 mg/ml into the spinal canal, computed tomography scan through the cervical spinal cord, and imaging reconstruction of the brachial plexus roots

2.2.3 Research contents

2.2.3.1 General characteristics of branchial plexus lesion: Ages,

sex, cause of trauma, side of trauma, combined trauma, time from injury to the taking CT myelography and undergoing surgery

2.2.3.2 Characteristics of brachial plexus lesions on CT

myelography:

- Description of lesion characteristics according to author Nagano (1989) and Carvalho (1997) include:

+ Abnormal root exit: Normally, the anterior and posterior roots are continuous with the spinal cord and emerge from the spinal canal

as soft as a sleeve Root exit abnormality is when an amputated or missing root exit is observed, while the anterior and posterior roots are normal

+ Anterior root lesion: No image of anterior roots or a decrease in the number of rootlets of anterior roots compared with the opposite side + Posterior root lesion: No image of posterior roots or reduced number of rootlets of posterior roots compared with the opposite side + Pseudomeningocele: The image of the herniated sac of cerebrospinal fluid that is usually accompanied by complete root avulsion, that is, the rootlets are not observed, however, there is also

a small percentage of associated pseudomeningocele with incomplete root avulsion, that is, the rootlets are still partially observed

+ Cerebrospinal fluid column defect: This sign is caused by the roots being avulsed and the spinal cord being pulled, causing the cerebrospinal fluid column defect at the location of the damaged root

- Location of root lesions: C5, C6, C7, C8, T1

- Correlation of damaged root location: C5 and C6, C5- C6 and C7, C8 and T1, C8- T1 and C7

- Describe the number of damaged roots: 0- 5 roots

- Classification of lesions avulsion by Nagano classification (1989): N (normal), A1 (incomplete root avulsion), A2 (incomplete root avulsion), A3 (complete root avulsion), D (complete root avulsion), M (complete root avulsion)

2.2.3.3 Characteristics of lesions in surgery:

Describe the types of lesions in surgery including root avulsion and other lesions (root fracture, root atrophy, edema of root, trunks, divisions and cords)

2.2.3.4 Compare CT myelography with surgery:

Compare and calculate the diagnostic relevance of root avulsion

on CT myelography and surgery at each root position, the upper root group (C5, C6 ± C7) and the lower root group (C8, T1 ± C7)

2.2.4 Image and data processing

- CT images of patients are stored as DICOM 3.0 and PNG

- CT myelography is diagnosed by the PhD student (under the supervision of the instructor) and saved as a Word file Statistics are stored in the computer in the form of Excel tables and then processed using SPSS 20.0 software

- Algorithms used in the study: Descriptive statistics of the signs

of rooting C5-T1 by absolute number and percentage, location, quantity, and extent of lesions at each C5-T1 root position The relationship between the location of the damaged roots and the signs

of lesions Comparison of diagnostic results of root avulsion between

CT myelography and surgery Calculation of the K value of CT myelography in the diagnosis of root avulsion lesions compared with surgery

Study map

Chapter 3 RESEARCH RESULTS

3.1 General characteristics of patients with brachial plexus injuries

- Brachial plexus injuries occur mostly in young men: The median

value was 28 (50% of patients had age ≤ 28, male/female = 15.3)

- The main cause of brachial plexus injuries is traffic accidents, accounting for 98.3% left > right Most of them have combined trauma (52.0%)

Most patients underwent CT scans within ≤ 90 days after injury, and the majority of patients underwent surgery within ≤ 120 days (4 months) after injury

3.2 Imaging characteristics of CT myelography in traumatic brachial plexus lesions

3.2.1 The figure for the location and the number of roots on CT myelography

Figure 3.1 The location of root injuries on CT myelography Comments: The figure for Root C6 reaches a peak of 82.7%

The other figures saw a gradual decrease, with each as follows: C7 (72%), C5 (68,2%), C8 (54,8%) and T1 (37,4%)

Figure 3.2 The number of root injuries on CT myelography Comments: The injuries tend to occur with more than 2 roots

Furthermore, the figure for injuries occurring with only 1 root holds a significantly low percentage of only 8 individuals, which is only 4.5% of the total number of patients There were no root injuries witnessed on

CT myelography within 11 individuals, which holds 6.1%

Figure 3.3 Multiple root injuries of Branchial plexus

Comments: The data for injuries with 2 or 3 roots holds a

tremendously higher percentage than the figure for injuries with 4 or

5 roots The longer group of roots, including C5, C6 and C5, C6, C7

3.2.2 The figure for the imaging of root injuries on CT

Pseudomeningocele 8 4,5 27 15,1 54 30,2 60 33,5 47 26,3

CBF column defect 2 1,1 4 2,2 9 5,0 8 4,5 4 2,2

Comments: The detailed signs of root lesions of brachial plexus

were found at the sites from C5-T1, in which signs of the dorsal and ventral roots accounted for a high percentage in most locations

Table 3.6 The number of imaging sigs on each root site

Comments: Each root site has 2 or 3 signs more than only 1

sign, there were no 4 and 5 signs of root lesions witnessed on CT myelography

Table 3.7 The imaging signs mostly combined

Locations Signs Number Total Percentage

(%)

C5

Ventral- dorsal root lesion-

Ventral- dorsal root lesion-

C6

Ventral- dorsal root lesion-

C7

Ventral- dorsal root lesion-

C8

Ventral- dorsal root lesion-

T1

Ventral- dorsal root lesion-

Comments: Signs of ventral - dorsal root lesion and ventral-

dorsal root lesion- psedomeningocele holds a tremendously higher percentage at all locations of root avulsion

Table 3.8 Classification of root avulsion by Nagano (1989) (n=179)

Comments: Classification of A3 lesions (complete avulsion)

hold a tremendously higher percentage at all location of root avulsion from C5 to T1, secondly, this is classification of A2 lesions (incomplete avulsion) and M lesions (root avulsion with pseudomeningocele)

3.3 Value of CT myelography in diagnostic of brachial plexus injuries compare with surgery

3.3.1 Root lesion of brachial plexus following surgery result

Figure 3 13 Location of the root lesion on surgery

Comments: Lesions of high-level root (C5,6,7) hold higher

percentage than low level root (C8, T1), C5 root lesion combined with C5 root lesion hold highest percentage (87,7%)

Figure 3.14 Number of root lesions Comments:

- The lesions tend to occur with more than 2 roots, lesion of 5

roots (complete lesion of roots) hold the highest percentage (40,2%)

- The lesion of only 1 root occurred 3 patients (2 patients occur

at C5 site and 1 patient occurred at C7 site) hold 1,7 %

- There is no root lesion occurring in 8 patients (4,5 %)

Table 3.12 Level of root lesion following surgery result