The role of spiral (helical) computerized tomography with three-dimensional reconstruction in pediatric solid tumors

Peripheral Primitive Neuroectodermal Tumor (Ppnet) of Pelvic Origin: Report of a Case Arising from an Unusual Location

A peripheral primitive neuroectodermal tumor arising from the abdominopelvic cavity is reported in a 24-year-old young male without any previous remarkable pathology. He was admitted to our hospital with complaints of urinary symptoms (acute urinary retention) and mild intestinal occlusion that had been present for three months. Physical examination and CT scan revealed a pelvic mass occupying the entire pelvic cavity. The diagnostic workup included a CT-guided biopsy which defined the tumor as a sarcomatous type. Radical surgery was performed including tumor resection, pelvic exenteration (bladder and prostate gland) and urinary and fecal diversion. Adjuvant chemotherapy (VAIA) was delivered once the histology was confirmed. We reviewed the available literature focusing on the varied nomenclature of this tumor (peripheral neuroepithelioma, Askin's tumor, Ewing's extraosseous tumor, peripheral adult neuroblastoma, peripheral primitive extracranial neuroectodermal tumor (PPNET), the clinical features, the role of diagnostic imaging techniques, pathologic assessment and controversial therapeutic management. In addition, the prognosis and survival of this rare condition were analyzed.

Clinical application of a three-dimensional imaging technique in infants and young children with complex liver tumors

INTRODUCTION

Three-dimensional (3D) imaging instead of two-dimensional (2D) computed tomography (CT) for diagnosis and preoperative planning in infants and young children with complex liver tumors is a promising technique for precision hepatectomy.

METHODS

This study was a retrospective analysis of 26 infants and young children with giant liver tumors involving the hepatic hilum who underwent precise hepatectomy at the Affiliated Hospital of Qingdao University between February 2012 and January 2015. All patients received upper abdominal contrast-enhanced CT scanning before surgery. 16 patients used Hisense CAS system for 3D reconstruction as the reconstruction group. While ten patients underwent 3D CT reconstruction by the CT Workstation as the control group. The clinical outcomes were analyzed and compared between the two groups. The 3D reconstruction of abdominal organs and blood vessels was generated using the Hisense CAS system. Diagnosis and preoperative planning assisted by the system was used for preoperative and intraoperative decision-making for precise hepatectomy.

RESULTS

All patients underwent successful surgery. The 3D models clearly demonstrated the association of liver tumors with the intrahepatic vascular system and provided a preoperative assessment of resectability, assisting surgeons in preoperative procedural planning. Anatomic hepatectomy was successfully completed in the reconstruction group. The mean operation time was shorter in the reconstruction group (137.81 ± 17.51 min) than in the control group (192 ± 34.66 min) (P < 0.01). The mean intraoperative blood loss was lesser in the reconstruction group (21.81 ± 14.05 ml) than in the control group (53.50 ± 21.35 ml) (P < 0.01). The difference was statistically significant.

DISCUSSION

2D CT scan images cannot accurately display the spatial relationship between the tumor and surrounding vasculature. The 3D reconstruction model used in this study gave detailed and accurate anatomical information and allowed for the assessment of tumor resectability and provided a detailed road map for preoperative decision-making and predicted the postoperative liver function.

CONCLUSIONS

3D visualization technology provides preoperative assessment and allows individualized surgical planning. Surgical controllability, accuracy, and safety can be improved in infants and young children undergoing precise hepatectomy for complex liver tumors.

Cost-effective pediatric head and body phantoms for computed tomography dosimetry and its evaluation using pencil ion chamber and CT dose profiler

In the present work, a pediatric head and body phantom was fabricated using polymethyl methacrylate (PMMA) at a low cost when compared to commercially available phantoms for the purpose of computed tomography (CT) dosimetry. The dimensions of head and body phantoms were 10 cm diameter, 15 cm length and 16 cm diameter, 15 cm length, respectively. The dose from a 128-slice CT machine received by the head and body phantom at the center and periphery were measured using a 100 mm pencil ion chamber and 150 mm CT dose profiler (CTDP). Using these values, the weighted computed tomography dose index (CTDIw) and in turn the volumetric CTDI (CTDIv) were calculated for various combinations of tube voltage and current-time product. A similar study was carried out using standard calibrated phantom and the results have been compared with the fabricated ones to ascertain that the performance of the latter is equivalent to that of the former. Finally, CTDIv measured using fabricated and standard phantoms were compared with respective values displayed on the console. The difference between the values was well within the limits specified by Atomic Energy Regulatory Board (AERB), India. These results indicate that the cost-effective pediatric phantom can be employed for CT dosimetry.

Intraoperative ultrasound for liver tumor resection in children

BACKGROUND

Primary hepatic neoplasms in children are rare tumors. All malignant and medically refractive benign primary pediatric liver tumors ultimately require surgical resection for cure. Accurate preoperative imaging including multidetector helical computerized tomography or magnetic resonance imaging (MRI) is necessary to determine resectability. In the literature intraoperative ultrasound (IOUS) has proven to be a vital adjunct to liver surgery in adults, but this is not well established in children.

MATERIALS AND METHODS

Between April 2003 and November 2014, children (<18-y-old) with a primary liver neoplasm, preoperatively evaluated with multidetector helical computerized tomography or MRI, who had IOUS used at the time of surgery were retrospectively reviewed.

RESULTS

Preoperative evaluation with high-resolution MRI and IOUS were discordant in 4 of 19 patients (21%). In one case, right hepatic vein involvement was not accurately assessed with MRI. Two cases showed tumor involvement in segment IV by MRI; however, IOUS revealed no medial segment involvement. The final patient had a large (>5 cm), solitary hepatic adenoma on MRI, but IOUS in this case revealed diffuse adenomatosis. The operative management was altered in three of these cases.

CONCLUSIONS

Although MRI can provide a detailed view of the hepatic anatomy and is an invaluable tool for preoperative planning for the pediatric patient with a primary liver neoplasm, IOUS may provide further and more up to date delineation of tumor extent and should be considered a crucial element in operative planning for hepatectomy in children.

Multidetector CT of musculoskeletal disease in the pediatric patient: principles, techniques, and clinical applications

Computed tomography (CT) plays an important role in the evaluation of musculoskeletal disease in the pediatric patient. With the advent of high-performance 16-section multidetector CT, images can be produced with subsecond gantry rotation times and with submillimeter acquisition, which yields true isotropic high-resolution volume data sets; these features are not attainable with older spiral CT technology. Such capabilities are particularly helpful in the evaluation of pediatric patients by virtually eliminating the need for sedation and minimizing dependence on patient cooperation. The role of three-dimensional (3D) volume imaging in the evaluation of pediatric musculoskeletal disease continues to evolve, with this technique becoming increasingly important in detection and characterization of lesions as well as in decisions about patient care. Specific designs and protocols for multidetector CT studies can be selected to minimize radiation dose to the patient. Principal clinical applications of 3D CT in evaluation of the pediatric musculoskeletal system include developmental abnormalities, trauma, neoplasms, and postoperative imaging.

Dose reduction in pediatric CT: a rational approach

PURPOSE

To determine size-dependent technique factors for pediatric computed tomography (CT) by using physically measured objective data.

MATERIALS AND METHODS

Six phantom cylinders (10-32 cm in diameter) were scanned with a clinical multi-detector row CT scanner. CT noise was statistically characterized for CT technique factors from 80 to 140 kVp and from 10 to 300 mAs. Dose measurements were performed with each phantom. Dilute iodine and tissue contrast were determined with computer calculations validated with measured data. The dose, noise, and contrast data were computer fit, and pediatric CT technique factors (milliampere seconds) necessary to maintain the contrast-to-noise ratio (CNR) were computed.

RESULTS

As compared with that in a reference cylindric adult abdomen of 28 cm in diameter, CNR was maintained at a constant level in pediatric patients of 25, 20, and 15 cm in diameter, respectively, when milliampere second values of 0.557, 0.196, and 0.054 of the adult milliampere second values were used. The corresponding doses were reduced to 0.642, 0.287, and 0.090 of the 28-cm-diameter adult dose, respectively. CT techniques for examination of pediatric heads measuring 15 and 13 cm, respectively, can involve the use of milliampere second values of 0.572 and 0.366 of those used for examination of a standard 17-cm-diameter adult head.

CONCLUSION

CT technique charts for pediatric abdominal and head examinations were produced on the basis of physically measured data; use of these tables will enable pediatric radiation dose to be reduced while CNR is preserved.

Prenatal diagnosis of agnathia-holoprosencephaly: three-dimensional imaging by helical computed tomography

We report a case of agnathia-holoprosencephaly which was prenatally diagnosed based on helical computed tomography (CT) images obtained at 23 weeks of gestation. Ultrasound examination first showed the presence of alobar holoprosencephaly, but the facial structures were not clearly detailed. However, three-dimensional imaging by helical CT precisely demonstrated the most striking feature of agnathia: absence of the mandible. This technique provided us valuable information that contributed to the in utero diagnosis. In utero helical CT is a useful examination tool for the diagnosis of osteogenic abnormalities.

Volume-rendered three-dimensional spiral CT: musculoskeletal applications

Spiral computed tomography (CT) is a powerful modality for evaluation of the musculoskeletal system, particularly when coupled with real-time, volume-rendering reconstruction techniques. Including volume-rendered spiral CT in routine musculoskeletal imaging protocols can change management in a significant number of cases. In cases of trauma, subtle fractures--particularly those oriented in the axial plane--are better seen on volume-rendered images. Complex injuries can be better demonstrated with volume-rendered images, and complicated spatial information about the relative positions of fracture fragments can be easily demonstrated to the orthopedic surgeons. The use of intravenously administered contrast material allows simultaneous evaluation of osseous and vascular structures within the affected area. Evaluation of suspected infectious or neoplastic disease is also aided by including volume-rendered imaging in the musculoskeletal spiral CT examination. The extent of disease can be thoroughly evaluated with volume-rendered images, and therapeutic planning--be it surgical or medical--is aided by the anatomic information available from volume-rendered images. Postoperative studies in patients with orthopedic hardware also benefit from volume-rendered imaging. Volume rendering eliminates most streak artifact and produces high-quality images on which the relationships among hardware, bones, and bone fragments are well demonstrated.

Outcome analysis of rhabdomyosarcoma of the lower urinary tract

PURPOSE

Multimodal therapy has resulted in a high cure rate for genitourinary rhabdomyosarcoma. We propose that the strategy of induction chemotherapy followed by excision and reconstruction without radiotherapy may provide a high cure rate without the late sequelae of pelvic radiotherapy.

MATERIALS AND METHODS

We reviewed the records of 13 patients with a mean age of 3.3 years diagnosed with rhabdomyosarcoma of the urinary tract from 1986 to 1996. The primary site was the bladder in 4 cases and prostate in 9. After biopsy confirmation of the diagnosis patients were treated with chemotherapy and subsequent surgery, while radiotherapy was reserved for those with residual disease.

RESULTS

After induction chemotherapy 8 patients underwent tumor excision via an organ sparing approach, which involved radical prostatectomy and partial cystectomy with or without bladder augmentation. In 5 patients the final pathological analysis showed positive margins. Repeat surgery in 6 patients included complete cystectomy and urinary diversion in 2 who had positive margins and recurrence after radiotherapy, urethrectomy and continent diversion for positive margins in 1, partial cystectomy and continent diversion in 1, and radical prostatectomy, partial cystectomy and continent diversion in 1 with stage IV disease who had local recurrence. In the latter case ileocystoplasty had been performed for a small noncompliant bladder. Six patients with microscopic residual or metastatic disease received radiotherapy. At a mean followup of 5.6 years 11 patients are disease-free. Continence was preserved in all reconstructed cases. Erections were reported in 8 patients, and renal function was maintained in 10.

CONCLUSIONS

Our results suggest that urinary tract reconstruction may be safely performed at primary excision surgery, radiotherapy induced morbidity may be minimized by limiting radiotherapy to residual and metastatic disease, frozen section results may be false-negative, potency may be achieved and radiological disappearance of the tumor should be confirmed histologically.