Imaging Modalities in Pediatric Oncology

Multiphase enhanced CT-based transformer for differential diagnosis and predicting surgical risk events of solid abdominal tumors in children

BACKGROUND

For pediatric patients with solid abdominal tumors, early diagnosis can guide clinical treatment decisions, and comprehensive preoperative evaluation is essential to reduce surgical risk. The aim of this study was to explore the feasibility of multiphase enhanced CT-based transformer in the early diagnosis of tumors and prediction of surgical risk events (SRE).

METHODS

A total of 496 pediatric patients with solid abdominal tumors were enrolled in the study. With Swin transformer, we constructed and trained two Swin-T models based on preoperative multiphase enhanced CT for personalized prediction of tumor type and SRE status. Subsequently, we comprehensively evaluated the performance of each model and constructed four benchmark models for performance comparison.

RESULTS

There was no significant difference in SRE status between tumor types. In the diagnostic task, areas under the receiver operating characteristic curves (AUC) of the Swin-T model were 0.987 (95 % CI, 0.973-0.997) and 0.844 (95 % CI, 0.730-0.940) in the training and validation cohorts, respectively. In predicting SRE, AUCs of the Swin-T model were 0.920 (95 % CI, 0.885-0.948) and 0.741 (95 % CI, 0.632-0.838) in the training and test cohorts, respectively. The Swin-T model achieved the best performance in both classification tasks compared to benchmark models.

CONCLUSION

The Swin-T model is a promising tool to assist pediatricians in the differential diagnosis of abdominal tumors and in comprehensive preoperative evaluation.

Imaging of pediatric extragonadal pelvic soft tissue tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper

The most common pediatric extragonadal pelvic cancers include germ cell tumors, sacrococcygeal teratomas, and rhabdomyosarcomas (arising from the urinary bladder, prostate, paratesticular tissues, vagina, uterus, and perineum). This paper describes the radiological and nuclear medicine features of these entities and provides consensus-based recommendations for the assessment at diagnosis, during, and after treatment.

A comparison between ultrasonography and single-phase computed tomography for preoperative assessment of solid abdominal tumors in children

OBJECTIVE

This study aimed to estimate the performance of single-phase-enhanced computed tomography and ultrasonography examinations in the preoperative evaluation of solid abdominal tumors and their relationship with relevant adjacent structures in children.

METHODS

This retrospective study included 50 pediatric patients with malignant solid abdominal tumors treated with surgical resection between 2009-2017. Preoperative computed tomography and ultrasonography were compared to operative findings (gold standard) in the diagnosis of invasion or encasement of adjacent structures. Accuracy, sensitivity, specificity, and positive and negative predictive values were evaluated.

RESULTS

Renal (20.4%) and neuroblastic (19.4%) tumors were the most common. Complete surgical resection with negative margins was achieved in 44 (88%) patients. The comparison between single-phase-enhanced computed tomography and ultrasonography findings showed the following results: sensitivity = 90.3% vs 86.6%, specificity = 86.8% vs 94.6%, negative predictive value = 95.3% vs 94.4%, positive predictive value = 75.3% vs 86.9%, and accuracy = 87.9% vs 92.2%. The correlation (kappa index) between computed tomography and ultrasonography examinations was 0.72 (p < 0.001). In 14% (7/50) of the patients, the invasion of adjacent structures was diagnosed by ultrasonography but not by computed tomography (1 patient had 2 invaded structures).

CONCLUSION

Ultrasonography can be considered a complementary method to single-phase-enhanced computed tomography in the preoperative evaluation of children with an abdominal tumor. The present study showed that ultrasonography and single-phase-enhanced computed tomography each possess a high accuracy in the preoperative planning of resection of solid abdominal tumors in children. Thus, it seems that the combination of both imaging methods would be enough for the evaluation of most abdominal tumors in the pediatric population.

A single enhanced phase is sufficient for the initial computed tomography evaluation of retroperitoneal tumors in children

PURPOSE

The goal of this study was to evaluate the incremental value of unenhanced phase in the initial evaluation of retroperitoneal tumors in children by comparison with an enhanced phase alone using computed tomography (CT).

MATERIALS AND METHODS

A total of 53 patients (26 girls, 27 boys) with a total of 53 tumors who had CT examination of the abdomen and pelvis for the initial assessment of retroperitoneal tumor were retrospectively included. All CT examinations were obtained with an unenhanced set of CT images and a set of CT images obtained after intravenous administration of iodinated contrast material. One junior and one senior radiologist independently evaluated the two sets in two separate reading sessions. CT images were analyzed for tumor calcifications, tumor location, vascular encasement, local invasion and tumor content.

RESULTS

Calcifications were present in 24/53 tumors (45%). On the enhanced set, the senior radiologist was able to detect calcifications in 22/24 tumors (92%) and the junior radiologist in 20/24 tumors (83%), yielding sensitivities of 92% and 83%, and specificities of 96.5% and 100%, respectively. Inter-observer agreement was excellent (Kappa=0.89). Tumor location was correctly determined by the senior radiologist in 53/53 tumors (100%) and 37/53 tumors (70%) by the junior radiologist. Using the unenhanced set, the senior radiologist was able to assess vascular encasement in 26/53 tumors (49%) against 21/53 (39%) for the junior radiologist. For tumor content, agreement between the enhanced and combined unenhanced and enhanced CT was 77% for both radiologists.

CONCLUSION

Enhanced CT performs as well as unenhanced CT for evidencing calcifications and is therefore sufficient for the initial assessment of retroperitoneal tumor in children.