Evaluation of Mammographic Positioning Quality at Cancer Diagnosis Centres in Rivers State, South South Nigeria

Mammographic positioning quality directly determines sensitivity for breast cancer detection, and suboptimal positioning results in missed cancers, unnecessary repeat examinations, and increased patient radiation dose. In Rivers State, South South Nigeria, the cancer diagnosis centres that provide mammography services have not been evaluated for positioning quality compliance with international standards. This study evaluates mammographic positioning quality at cancer diagnosis centres in Rivers State. A retrospective image quality audit is applied to 300 archived mammographic examinations across three cancer diagnosis centres in Port Harcourt from 2022 to 2023. Each craniocaudal and mediolateral oblique view is assessed against the PGMI (Perfect, Good, Moderate, Inadequate) grading system by two independent assessors with inter-rater reliability calculated. Positioning quality indicators assessed include posterior nipple line, mediolateral oblique pectoralis muscle extent, skin folds, and symmetry. Descriptive statistics and Cohen's kappa for inter-assessor agreement are computed in SPSS. Available mammographic quality literature from South South Nigeria identifies insufficient mediolateral oblique pectoralis major muscle visualisation and inframammary angle exclusion as the most prevalent positioning deficiencies, particularly in high-throughput screening settings. The ACR Mammography Quality Standards Act criteria and the European Reference Organisation for Quality Assured Breast Screening guidelines provide the normative standards. Findings are expected to reveal that fewer than 60 percent of views meet the Perfect or Good PGMI standard. Recommendations address structured mammographic positioning training, regular phantom image quality auditing, and radiographer positioning competency certification at Rivers State cancer diagnosis centres. Keywords: mammographic positioning, image quality, PGMI, Rivers State, South South Nigeria.