Mature cystic teratoma is a germ cell tumour with a bimodal peak of occurrence. Common sites of involvement include the pelvis, retroperitoneum, and mediastinum. It manifests with non-specific symptoms of abdominal distension with mass effect. Owing to the large size at presentation, ultrasonography is the first-line investigation; however, it does not always yield all three components. Hence, contrast-enhanced CT is diagnostic, as it enables the identification of all the components of the teratoma. It also delineates the relations with other abdominal organs, facilitating surgical excision and histopathology. The authors present a case of primary retroperitoneal mature cystic teratoma in a 3-year-old child. In this case, the imaging findings are sufficient to arrive at a probable histopathological diagnosis and obviate the need for pre-operative imaging-guided biopsy. The take home message is the importance of localisation of lesions to the retroperitoneal cavity and to a specific compartment with further classification based on morphological characteristics, like presence of fat, cystic tissue, and calcifications. Key Points 1. Benign mature cystic teratomas, known as dermoid cysts, are the most common germ cell tumours and have bimodal peak of occurrence. They primarily occur in the gonads, but may arise in the anterior mediastinum, retroperitoneum, or sacrococcygeal region. 2. Mature cystic teratomas contain derivatives of at least two germ cell layers and can show the characteristic presence of cystic components, fat, teeth, or cartilage not seen in unison in other tumours. 3. They can be diagnosed and prognosticated based solely on imaging findings, obviating the need for pre-surgical biopsy, which is crucial, especially in paediatric patients.
Cardiac imaging is crucial for diagnosing and managing coronary artery disease. While most imaging modalities focus on either anatomical or physiological assessment of coronary artery disease, novel hybrid techniques capable of providing both in a single imaging session represent an important advancement in the field. This review summarises the technique, diagnostic performance, clinical utility, limitations, and cost-effectiveness of the principal hybrid modalities: coronary CT angiography (CCTA) c, PET with CCTA (PET-CCTA), and cardiovascular magnetic resonance (CMR) imaging. CCTA with fractional flow reserve applies computational fluid dynamics modelling to standard CCTA data to derive non-invasive fractional flow reserve estimates without additional radiation or contrast exposure. Diagnostic accuracy, at appropriate values, can be high enough to reduce rates of invasive coronary angiography. The application of AI to CCTA for automated plaque quantification and stenosis grading is promising but currently limited by its discordance with invasive angiography. PET-CCTA combines myocardial perfusion imaging with coronary anatomy in a single session with higher specificity than CCTA alone, but at the cost of greater radiation exposure. Finally, CMR provides radiation-free tissue characterisation across multiple techniques such as stress perfusion, late gadolinium enhancement, and strain imaging, each with their unique features. Taken together, PET-CCTA currently offers the most robust integration of anatomy and physiology, while CMR continues to advance rapidly as a compelling alternative, particularly where radiation-free evaluation is preferred. The authors have summarised key evidence on how these hybrid approaches enhance detection of obstructive coronary stenosis, guide therapeutic decisions, and how these technologies are implemented today.
