MR Volumetry of Pituitary Gland in Indian Adults to Establish Normal Reference Values
Joish Upendra Kumar, Kavitha Y
1. Assistant Professor, Department of Radiodiagnosis, JJM Medical College, Davangere, Karnataka, India. 2. Assistant Professor, Department of Otorhinolaryngology, JJM Medical College, Davangere, Karnataka, India.
Correspondence Address :
Dr. Joish Upendra Kumar,
Department of Radiodiagnosis,
Bapuji Hospital, OPD Block, JJM Medical College,
Davangere, Karnataka-577004, India.
: Surgery and anaesthesia provoke anxiety in almost all the patients, causing increased sympathetic activity, leading to increase in heart rate and blood pressure. Non pharmacological means are now being evaluated for relieving anxiety and stress during perioperative period due to their safe and non interfering profile among the multitude pharmacological interventions and music is one of the most practical and easy to use application.
Aim: This study was conducted to evaluate the effects of a preoperative music intervention on changes in anxiety levels and its indirect haemodynamic parameters which are mean arterial pressures, heart rate and serum catecholamine levels in patients undergoing surgery.
Materials and Methods: A total of 100 patients were included of which 50 each were assigned to the music intervention group and the control group. Serum catecholamine levels were assessed in 10 patients from each group randomly. Patients in the intervention group listened to music during the preoperative period for a minimum period of 20 minutes which was continued till the patient was rolled into the operation theatre. Patients in the control group received standard care without any intervention. Data was collected preoperatively at time 1 (T1) in the pre-surgical area and at time 2 (T2) before induction in the operation theatre and analysed with professional statistical software.
Results: There was statistically significant decrease in the HR, MAP and anxiety score (2-tailed significance <0.001), in the intervention group as compared to those in the control group. Also there was significant decrease in the serum epinephrine levels with significance (0.039) but norepinehrine levels were not declined significantly in the control group.
Conclusion: Music is a non-invasive and low-cost intervention that can be easily implemented in the preoperative setting and the findings suggest that preoperative music can reduce HR, MAP and anxiety.
|Keywords : Gender variations, Mean pituitary volume, T1 weighted multiplanar imaging|
Pituitary gland being the master endocrine gland, is the vital link to many endocrine disorders. With the widespread use of Magnetic Resonance Imaging (MRI) in the evaluation of pituitary gland abnormalities, many changes in the size of the pituitary gland can be observed with or without identifiable focal lesions. Subtle convexity of the superior surface of the gland can be a normal variant but also mimic an underlying lesion (1). Pituitary height is the most commonly used measurement to detect hyperplasia (2),(3). However, in some conditions like pregnancy (4), anorexia and endocrine disorders (5), overall size of the gland is increased which can be assessed by measuring volume of the gland. Pituitary gland volume measurements more reliably detect the changes in overall size of the gland. To ascertain whether such variations in glandular volume are significant, it is imperative to know the normal range of the pituitary gland volumes. It is also known that the pituitary gland volumes vary with ethnicity and also among different races (6). There is lack of data on the normal range of pituitary gland volumes among Indian population till date.
|MATERIAL AND METHODS|
A prospective study was carried out in the Department of Radiodiagnosis, JJM Medical College, Davangere, India, between May to September 2016 (5 months), in which 50 apparently healthy adults, aged between 15 years and 80 years, were subjected to MRI of the pituitary gland (power based sample size calculation was done). Persons with any known neurological disease, endocrine disease, psychiatric disease or any other co- morbidity likely to have an influence on pituitary gland and individuals with contraindications for MRI including claustrophobia were not considered for the study. Careful history eliciting and detailed general physical examination was carried out to exclude any of the above mentioned conditions.
After taking informed consent from the individuals, MRI was performed with a 1.5 T imager (Achieva, Philips). A T1 weighted multiplanar imaging of brain was done with parameters as described in (Table/Fig 1).
The sagittal images were used for pituitary gland tracing. All slices in which pituitary gland was seen were selected and the gland was manually traced in each of the slices by using the area tool for irregular shapes. The pituitary gland areas obtained for all slices were summed. Pituitary gland volume (in mm3) was obtained by adding areas of the gland in all slices and multiplying by a factor of 0.9, as slice thickness of images was 0.9 mm. Pituitary stalk was excluded from the tracings. However, both anterior pituitary and posterior pituitary bright spot were included in the tracing in each slice as depicted in (Table/Fig 2). This method of tracing pituitary gland for volumetry is akin to that used by Takano K et al.,(7).
The data obtained was tabulated into class intervals of different age groups and gender. Mean and standard deviation was calculated for each age group. Thereafter test for significance for variations of the mean volumes among different age groups was done using a two tailed paired ‘t’ test.
There were 27 males and 23 females included in the study. The mean age of participants was 36.3 years. The youngest of them was a 15 years old male and oldest an 80 years old male. Age group of 21-30 years comprised of the maximum number of individuals and included 10 males and 6 females. Gender and age distribution of the participants is depicted in (Table/Fig 3).
The mean pituitary volume found in males was 4.78cm3 and in females it was 4.8cm3 . Mean pituitary gland volumes and standard deviations obtained in different age groups are depicted in (Table/Fig 4). The largest pituitary gland volumes were seen between 21-30 years in males with a mean of 5.34cm3 . However, in females, the largest pituitary glands were seen in 11 to 20 years age group with a mean of 5.61cm3 which was significantly larger than that found in males of similar age group (4.9cm3 , p-value <0.05). There were no significant differences in pituitary volumes between the two genders at other age groups.
The elderly individuals aged more than 50 years showed the smallest pituitary glands in both genders with a mean of 3.51cm3 in males and 3.96cm3 in females. These individuals had significantly lower pituitary volumes as compared to ndividuals in 2nd to 4th decades of life (p-value of less than 0.04). Paired-‘t’ test values of significance of variations of pituitary gland volumes across different age groups is given in (Table/Fig 5). A scatter diagram comparing the pituitary volumes between males and females is depicted in (Table/Fig 6).
Variations of pituitary gland volumes with age and gender in Indian population were studied in view of scant data available on the same.
In the present study, the pituitary gland was traced on all sagittal slices obtained by T1 weighted protocol employing thin slices. The volume was measured by summing the areas of the gland on all slices and multiplying by 0.9 mm, the slice thickness. Takano K et al., (7) had used similar method to measure pituitary gland volume, but in adolescents. SN Lurie et al., (5), had also used sagittal T1 weighted images for volume measurements. However, the slice thickness obtained was 3 mm. Two types of volume calculations were done in that study. One employing the formula:-
Pituitary Gland Volume = ½ X Height (in Sagittal Plane) X Thickness (in Sagittal Plane) X Width (on Coronal Image),
same formula also used by Ibinaive PO et al., (8), but coronal images were chosen for height measurements.
The gland volume was also measured by tracing the area of the gland in sagittal images and multiplying by its width.
The mean pituitary gland volumes, among population of more than 50 years of age, in the present study (3.51cm3 in males and 3.96cm3 in females) was smaller than that obtained by SN Lurie et al., (5) (4.1cm3 ) that was done in American population. In people aged under 50 years, the pituitary gland volumes measured by SN Lurie et al., (5.17cm3 ) are comparable to similar volumes in the 2nd and 3rd decade age groups in the present study (5). Ibinaive PO et al., (8), found pituitary gland volumes of 3.34cm3 and 3.28cm3 in Nigerian males and females respectively, which are significantly smaller than those obtained in current study. A concise comparison of results of these studies is depicted in (Table/Fig 7).
There were no significant gender related variations reported by SN Lurie et al., (5) and Ibinaive PO et al., (8), in contrast to present study which shows significantly higher volumes in females of pubertal age group in comparison with male counterparts of similar age (p-value <0.03). Similar difference at pubertal age group was also noted by Takano K et al.,(7) among Japanese, as also Elster AD et al., (3) and Tsunoda A et al., (2).
Though, a thorough history taking and general physical examination was done, no haematological examination or hormonal analysis was done, leading to possibility of missing subclinical conditions in the participants.
The sample size used in this study, though was based on power based sample size calculation formulae, was less than that used in some studies like Ibinaive PO et al., (8), but significantly more than that used by SN Lurie et al., (5).
Manual tracing of the pituitary gland was done in all sagittal slices. This could yield a more accurate measurement than that of formulae for volume measurement, due to variations in shape of the gland. Still there is a possibility of manual errors. Three dimensional volumetry software may be used as alternative, but it was observed that technical errors could lead to oversampling or under sampling of the gland. Hence, manual tracing was opted for.
Pituitary volumes are best predictors of pituitary gland size due to the variations in size and shape of the gland. Normal values of pituitary glands with gender and age variations, among Indian population, were found out in this study, as scarce data was available on the same. Pituitary gland volumes among Indians were found to be comparable to previously established measurements among Americans and were significantly larger than among the Nigerians. The establishment of normal pituitary gland values among Indians not only help to recognise subtle pathologies of the pituitary gland but also pave way for better understanding of behavioural and personality related differences among different ethnic groups. The data obtained in this study can be used as reference range for Indian population for further studies.
Acknowledgements to Mr. Rajendra Kumar J, Bangalore, for tabulating data and providing statistical assistance.
|TABLES AND FIGURES|
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