ROLE OF MULTI-SLICE SPIRAL CT IN THE EVALUATION OF NECK MASS WITH CYTOLOGICAL CORRELATION

The swellings in the neck can be caused by innumerable pathological lesions arising from the various anatomical structures lying therein. Multi-Detector CT (MDCT) has now become the new standard in a radiological imaging modality. The utilization of MDCT has resulted in improved resolution and considerable reductions in scan acquisition and display time. Aim and Objective: This study is an effort to assess the role of MDCT in detection, characterization and diagnosing neck pathologies that correlate cytologically. Methods: A study of 50 cases in a clinically suspected neck mass was studied. Contrast-enhanced CT neck was done, and Specific CT criteria were used to characterize the mass so that a probable diagnosis could be made. MDCT diagnoses then compared with cytological results to conclude efficiency of MDCT analysis of neck mass. Results: In our study, the correlation between MDCT diagnosis and pathological diagnosis was significant (p<0.001) when we compare both the modalities for diagnosing malignancy. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy is 92.3%, 87.5%, 88.9%,91.3%, 90% respectively. Conclusion: Multi-detector computed tomography helps in precise anatomical localization and characterization of neck masses. Hence, it will be a method of choice for initial evaluation, preoperative planning, and biopsy targeting and postoperative follow-up.


INTRODUCTION
The neck is a wide anatomical area, and a detailed understanding of neck anatomy is critical to reaching a differential diagnosis [1]. It encompasses a wide variety of anatomical structures that belong to different organ systems, and thus the swellings in the neck can be caused by innumerable pathological lesions arising from the various anatomical structures lying therein [2]. In addition to metastases from malignancies commonly are neck masses, cervical lymphadenopathy is one of the common causes of neck masses in our country due to the prevalence of tuberculosis [3]. Clinical history and examination are usually the first step in the diagnostic evaluation of such masses and help in the gross differentiation of such masses. Multi-Detector CT (MDCT) has now become the new standard in a radiological imaging modality. The utilization of MDCT has resulted in improved resolution and considerable reductions in scan acquisition and display time [4]. This study is an effort to assess the role of MDCT in detection, characterization and diagnosing neck pathologies, which may help in deciding further course of management, and findings will be correlated cytologically. Study population: fifty patients irrespective of age and sex presenting with neck mass studied over the period of one year after fulfilling inclusion criteria.

Exclusion criteria:
We have tried to reach a definite diagnosis utilizing the available clinical, radiological & cytological data. Each patient of our study was subjected to thorough clinical examination and radiological evaluation. Specific CT criteria were used to characterize the mass so that a probable diagnosis could be made. USG guided FNAC then performed aseptically and later on, and the cytological analysis was carried away. MDCT diagnoses then compared with cytological results to conclude the efficiency of MDCT analysis of neck mass.
mean age of 42.46.  In the present study's most common presenting complaint was that of neck mass, which was seen in 48 (96%) patients a were mainly due to cervical lymphadenopathy, which was an associated complaint with the primary site of malignancy. The second most frequent presenting complaint was that of painless Carcinoma alveolar process 1 ulcers seen in 21 cases (24%) of patients.

MDCT DIAGNOSIS N
Of the lesions involving the suprahyoid neck spaces, the maximum number of lesions were recorded in the buccal space (n = 6) majority of which were found to be squamous cell carcinoma. In the infrahyoid neck, the predominant lesions (n =17) were observed in the visceral space. Thyroid origin lesions constitute the bulk of the visceral space lesions. The distribution of neck mass into benign and malignant groups according to MDCT characters shown in table 2.
32 patients out of 50 present with cervical lymphadenopathy. The majority of (n=22) were due to metastatic secondary with a known primary in the headneck region. Two cases of lymphoma and six cases of tubercular lymphadenitis were also diagnosed.
The CT criteria used to characterize the lesions were margins, enhancement pattern, necrosis, surrounding soft tissue infiltration, bone erosion, vascular invasion and the extent to adjacent neck space. And the findings are tabulated in Table 3   Table 3: Distribution of various CT characters in between malignant and benign lesions Twenty-seven lesions were diagnosed on CT as malignant. There were three cases that were diagnosed as malignant lesion two was the malignant transformation of adenomatous goiter and one was tongue carcinoma, which on pathological test turned out to be adenomatous goiter and chronic cell infiltrate. Of the 23 cases identified as benign, 21 turned out to be benign while two were malignant lesions on histopathology.
There were two cases which were diagnosed as a chronic inflammatory lesion of masticator space and one was inflammatory pseudotumor they were diagnosed as undifferentiated sarcoma and round cell tumor respectively on histopathology.
The diagnoses of CT have been compared with the histopathology diagnoses in

DISCUSSION
In the present study most, the common presenting complaint was that of neck mass, which was seen in 48 (96%) patients who were mainly due to cervical lymphadenopathy, which was an associated complaint with the primary site of malignancy. The second most frequent presenting complaint was that of painless ulcer seen in 21 cases (24%) of patients, were mostly seen in gingivobuccal and tongue cancers. Dobrossy L [5] did a study in the year 2005 in which the oral cavity was the most common site of lesion seen in 40% of patients and presented with complaints of non-healing oral ulcers In the present study, 34% of the patients had visceral neck space involvement, which included pyriform sinus, larynx, thyroid and esophageal in the present study. A similar finding was noted in a study done by Mathur R [6] in the year 2016. of various studies and made a pooled estimate in which sensitivity was 52%, and specificity was 93% for MDCT detecting malignant lesion.

CONCLUSION
Multi-detector computed tomography helps in precise anatomical localization and characterization of neck masses. Hence, it will be a method of choice for initial evaluation, preoperative planning, and biopsy targeting and postoperative follow-up.

Limitations:
The current study included all neck mass lesions, irrespective of their diagnosis and histopathological variety. It would have been better if an individual type of lesion could be considered separately.
A large-scale study with great logistic support and adequate randomization is thus recommended.
Clinical uses: Accurate delineation of pathologies by MDCT provides a reliable preoperative diagnosis, helps in staging, aspiration cytology, planning of biopsy and post-treatment follow up. Hence, Multidetector CT is currently one of the most versatile and powerful imaging procedures for the initial evaluation of neck masses.