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Magnetic resonance imaging in middle cerebral artery infarct and its correlation with functional recovery.

INTRODUCTION

Middle cerebral artery stroke is described as the sudden onset of focal neurological deficit due to brain infarction in the territory supplied by the MCA. Infarcts that occur within the distribution of this vessel lead to significant neurologic sequelae. Patients have variable recovery of neurological functions after MCA stroke, but knowledge of the time course and extent of recovery is limited.

AIMS AND OBJECTIVES

* To assess the extent of infarction in MCA stroke from the MRI brain taken within 48 hours of onset of symptom.

* To study the association between MRI findings and early clinical outcome in MCA Stroke.

METHODS

Table 1

Study             Diagnostic Test Evaluation
Design

Study Setting     All cases coming to medicine casualty with
                  symptoms of MCA stroke, Govt. Medical College
                  Kozhikode, Kerala, India

Study Period      March 2014 to September 2015

Study Method      * All patients coming with symptoms of MCA
                    stroke had detailed clinical evaluation with
                    emphasis on possible risk factors. Initial
                    GCS score was calculated for those patients
                    at the time of admission. MRI scan including
                    FLAIR, diffusion weighted images and
                    angiogram was taken within 48 hours for study
                    subjects. Percentage of area showing
                    diffusion restriction in affected MCA
                    territory and DW-ASPECTS score was used to
                    assess the extent of infarct. Treatment
                    included anti-platelets and anti-oedema
                    measures. Early functional recovery was
                    assessed clinically using Glasgow coma scale
                    calculated on day seven. MRI findings and
                    clinical outcome was compared and association
                    between two were studied

Sample Size       50 patients All patients satisfying inclusion
                    criteria were included in the study

Inclusion         MRI brain taken within 48 hours of onset of
Criteria            symptoms. Age between 18-80 years

Exclusion         Patient with previous episode of major stroke
Criteria          Presence of intracerebral bleeds Involvement
                  of other vascular territory

MRI Protocols     MRI with a 1. 5 T MR system (GE HDXT), 16
and Imaging       channel with 18 superconducting shim coil and
                  a dedicated 8 channel 13-element phased-
                  array brain coil with the patient lying
                  supine. The imaging protocols include mainly
                  axial T2 FLAIR, DWI and MRA

Statistical       Severity of MCA infarct assessed as
Analysis          percentage and frequency. Clinical outcome
                  assessed as percentage and frequency.
                  Relation between MRI and clinical outcome
                  calculation done using incidence and relative
                  risk. Statistical test used is chi square
                  test. P value <0. 05 will be taken as
                  significant


ETHICS

The study was approved by the Institutional Research Committee and Ethics Committee of Government Medical College, Kozhikode, Kerala, India.

STATISTICS

The Null Hypothesis (H0) assumes that there is no association between the predictor and outcome variables in the study population. When we conclude that there is statistical significance, the P value tells us what the probability is that our conclusion is wrong when in fact H0 is correct. The lower the P value, the less likely that our rejection of H0 is erroneous. By convention, most analysts will not claim that they have found statistical significance if there is more than a 5% chance of being wrong (P=0.05).

RESULTS

Majority of patients with MCA stroke were in age group between 50-69 years (54%).

DISCUSSION

MRI findings and its correlation with early clinical recovery in fifty patients who presented to Govt. Medical College, Kozhikode, was studied.

Age

Age group of the patients in our study varied from forty two to seventy nine. The mean age was 63.2.

In a similar study by Dr. Dawn E Saunders and others on measurement of infarct size using MRI in prediction of prognosis of MCA infarct, mean age of patients with cortical MCA territory infarct was 66. 5 yrs.

According to Asplund et al 2009, the chance of having a stroke approximately doubles for each decade of life after age 55 and while stroke is more common among the elderly, an increasing number of people under 65 are also having strokes.

In our study out of 10 deaths in the first 7 days, 6 were in the age group >70.

In general, according to the literature the risk of early fatality from stroke increases with age.

Comorbidities

94% patients in our study had one or other comorbidities. Systemic hypertension was the most common among them (58%) followed by diabetes (24%) and ischaemic heart disease (16%). More than two comorbidities were found in 40% patients. It has been proved in many studies before, that the most important modifiable risk factor for both cerebral infarction and intracerebral haemorrhage is hypertension. (1,2,3) Some literature say diabetes is associated with a two- to fourfold increase in the risk of ischaemic stroke (4) and also with a poorer stroke outcome and increased stroke mortality. (5)

Extent of Infarct

It was calculated using percentage of infracted area and DW-ASPECTS score in diffusion weighted images.

It was proved in other studies like the one done by C. Oppenheim et al that early Diffusion-Weighted Imaging (DWI) provides reliable quantitative information for the prediction of stroke patients at risk of malignant brain infarct. In our study, only 7 (14%) patients had infarct size more than 50%. Of the 7 patients who had infarct size more than 50%, five (71%) did not survive till day 7, while two patients survived. Of the two patients survived, one showed worsening of neurological status while condition of other patient remained static. Infarct size showed statistical significance with neurological status on day 7.

In our study, DW ASPECTS score was used as an important method to assess the radiological severity of MCA infarct. Score has been divided into 3 groups (Score <3, 3-7, 8-10). Of the total 50 patients studied, six (12%) patients had score <3, thirteen (26%) patients had score 3-7, thirty one (62%) patients had score 8-10. Of the six patients who had DW-ASPECTS <3, five patients (83%) did not survive till day 7, only one patient survived whose condition was worsened. DW-ASPECTS score showed statistical significance with day 7 survival and early neurological outcome. There are no previous studies comparing early neurological outcome and extent of MCA infarct. However, various studies have proved that there is definite relation between long-term prognosis and volume of infarct.

In a study conducted by R. Gilberto Gonzalez, it was suggested that all patients who had diffusion abnormality of greater than 72 mL had a poor outcome regardless of treatment. Clinical tradition holds that infarcts involving approximately 1/3 of the MCA territory (~100 mL) or greater have high likelihood of poor outcomes.

Also in another study by Dr. Dawn E Saunders and others it was shown that the volume of MCA infarction visible on MRI in patients within 72 hours of onset predicts outcome; the larger the infarct volume, the worse the outcome and patients with an initial infarct volume of less than 80 [cm.sup.3] had a better outcome than patients with larger infarct volumes. In both these studies, long-term clinical outcome was assessed rather than early outcome.

In our study we did not calculate the infarct volume, instead DW ASPECTS score and percentage of infarcted area was assessed. We assessed short-term outcome of the patients, which is after 1 week. We did not do a long-term follow-up.

Ml Occlusion

MRA appears to provide information about intracranial arterial occlusion with a high rate of accuracy. In our study, MR Angiogram was done for all patients and patency of M1 segment of middle cerebral artery was assessed. Five patients showed M1 segment occlusion. Out of 5 patients who had M1 occlusion, 4 expired within 7 days; only one patient survived whose neurological status was worsened.

M1 occlusion showed statistical significance with day 7 survival (p value <.001) and neurological outcome on day 7. In a study with 26 patients, Barber et al (6) found that patients with absent M1 flow had larger lesion volumes, larger acute DWI lesion volumes, larger final infarct volumes and poorer clinical outcomes than the patients with M1 flow.

Prognosis

MCA infarct has poor prognosis according to our study; 20% patients expired within 7 days. Neurological improvement after one week was seen only in 32%.

Most of the previous studies did long-term follow-up for patients. In one study, the percentages of independent patients after MCA stroke varied between 40% and 63%. In some other studies, the percentage of survivor with a good recovery has been particularly low, i.e. 12% to 17%.

It is presumed from our study that DW ASPECTS score and MR angiogram can be used as potential tools for diagnosing, prognostication and predicting the early neurological outcome in MCA infarct. There is a definite increase in immediate mortality among patients who have larger area of infarct.

Case 1: M1 occlusion present, extent of infarct >50%, DW ASPECTS <3, patient died within seven days.

Case 2: Extent of infarct <50%, DW ASPECTS -7, M1 occlusion absent, patient's neurological condition remained static.

Case 3: DW ASPECTS -5, extent of infarct >50%, M1 occlusion absent, patient's neurological condition improved after 7 days.

Case 4: DW ASPECTS <3, Extent of infarct >50%, M1 occlusion present, patient expired in seven days.

Case 5: DW ASPECTS-8, Extent of infarct <50%, M1 occlusion absent, patient's neurological condition improved.

REFERENCES

(1.) Matsumoto N, Whisnant JP, Kurland LT, et al. Natural history of stroke in Rochester, Minnesota, 1955 through 1969: an extension of a previous study, 1945 through 1954. Stroke 1973;4(1):20-9.

(2.) Shafer SQ, Bruun B, Richter RW. The outcome of stroke at hospital discharge in New York City blacks. Stroke 1973;4(5):782-6.

(3.) Adams GF, McComb SG. Assessment and prognosis in hemiplegia. Lancet 1953;265(6780):266-9.

(4.) Abbott RD, Donahue RP, MacMahon SW, et al. Diabetes and the risk of stroke. The Honolulu heart program. JAMA 1987;257(7):949-52.

(5.) Olsson T, Viitanen M, Asplund K, et al. Prognosis after stroke in diabetic patients. A controlled prospective study. Diabetologia 1990;33(4):244-9.

(6.) Barber PA, Davis SM, Darby DG, et al. Absent middle cerebral artery flow predicts the presence and evolution of the ischemic penumbra. Neurology 1999;52(6):1125-32.

Neethu Tressa Jose [1], Rajan Padinharoot [2], Vadakooth Raman Rajendran [3], Geetha Panarkandy [4]

[1] Junior Resident, Department of Radiodiagnosis, Government Medical College, Kozhikode.

[2] Professor, Department of Radiodiagnosis, Government Medical College, Kozhikode.

[3] Professor and HOD, Department of Radiodiagnosis, Government Medical College, Kozhikode.

[4] Additional Professor, Department of General Medicine, Government Medical College, Kozhikode.

Financial or Other, Competing Interest: None.

Submission 29-05-2016, Peer Review 20-07-2016, Acceptance 26-07-2016, Published 31-08-2016.

Corresponding Author:

Dr. Neethu Tressa Jose, Andaseril House, Anickadu P. O., Kottayam- District-686503, Kerala.

E-mail: neethutreesajose@gmail.com

DOI: 10.14260/jemds/2016/1152

Table 2

Infarct
Size >50%     Neurological Status on Day 7 Based on GCSTotal

             Improving    Static    Worsen    Death

Yes              0           1         1        5        7
No               16         11        11        5        43
Total            16         12        12        10       50

Table 3

DW Aspects    Neurological Status on Day 7 Based on GCS Total
Score
              Improving    Static    Worsen    Death

DW <3             0           0         1        5        6
DW 3-7            5           7         1        0        13
DW 8-10           11          5        10        5        31
Total             16         12        12        10       50
Table 3

Table 4

M1           Neurological Status on Day 7 Based on GCSTotal
Occlusion
             Improving    Static    Worsen   Death

Yes              0           0        1        4        5
No               16         12        11       6        45
Total            16         12        12       10       50

Fig 1: Age distribution

Age (years)   No. of patients (N=100)

30-49                 6
50-69                27
>70                  17

Incidence of MCA stroke was more among males (60%)

Note: Table made from bar graph.

Fig 2: Sex distribution

Males      30
Females    20

94% of patients had one or more comorbidities.

Note: Table made from pie chart.

Fig 3: Co morbidities

                        No. of patients (N=50)
hypertension                     29
IHD                               8
DM                               12
Minor stroke                      5
RHD                               1
POVD                              4
DLP                               8
>1 CO MORBIDITIES                20

Most of the patients (54%) had a moderate (9-12) GCS at
the time of presentation; however, it did not have any
correlation with 7-day outcome.

Note: Table made from bar graph.

Fig 4: Initial GCS

            NO OF PATIENTS

mild             13
moderate         27
severe           10

Only seven patients (14%) had infarct size more than 50%

Note: Table made from bar graph.

Fig 5: DWI-ASPECTS score

score <3      6
score 3-7     13
score 8-10    31

Most of the patients (62%) had an initial DWI-ASPECTS
score 8-10.

Note: Table made from pie chart.

Fig 6: M1 Occlusion

       MALE   FEMALE
YES      3       2
NO      28      18

Only 5 patients had M1 occlusion.

Note: Table made from bar graph.
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Article Details
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Title Annotation:Original Research Article
Author:Jose, Neethu Tressa; Padinharoot, Rajan; Rajendran, Vadakooth Raman; Panarkandy, Geetha
Publication:Journal of Evolution of Medical and Dental Sciences
Article Type:Report
Date:Sep 1, 2016
Words:2060
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