Endoscope-Assisted Traversal of a Ureteral Stricture From Percutaneous Nephrostomy Access.

Interventional radiology-operated endoscopy has a small but growing number of applications. In this clinical case report, we describe the use of an endoscope to assist the traversal of a high-grade ureteral stricture from percutaneous nephrostomy (i.e., antegrade) access. Direct visualization of the stricture allowed the identification of a central channel that was not present in fluoroscopic images, making endoscopy essential to the technical success of the procedure. Endoscopy is a powerful adjunct to image-guided techniques, particularly in challenging interventions or cases with complex anatomy.

Localization of Parathyroid Disease in Reoperative Patients with Primary Hyperparathyroidism.

The localization of persistent or recurrent disease in reoperative patients with primary hyperparathyroidism presents challenges for radiologists and surgeons alike. In this article, we summarize the relevant imaging modalities, compare their accuracy in identifying reoperative disease, and outline their advantages and disadvantages. Accurate localization by preoperative imaging is a predictor of operative success, whereas negative or discordant preoperative imaging is a risk factor for operative failure. Ultrasound is a common first-line modality because it is inexpensive, accessible, and radiation-free. However, it is highly operator-dependent and less accurate in the reoperative setting than in the primary setting. Sestamibi scintigraphy is superior to ultrasound in localizing reoperative disease but requires radiation, prolonged imaging times, and reader experience for accurate interpretation. Like ultrasound, sestamibi scintigraphy is less accurate in the reoperative setting because reoperative patients can exhibit distorted anatomy, altered perfusion of remaining glands, and interference of radiotracer uptake. Meanwhile, four-dimensional computed tomography (4DCT) is superior to ultrasound and sestamibi scintigraphy in localizing reoperative disease but requires the use of radiation and intravenous contrast. Both 4DCT and magnetic resonance imaging (MRI) do not significantly differ in accuracy between unexplored and reoperative patients. However, MRI is more costly, inaccessible, and time-consuming than 4DCT and is inappropriate as a first-line modality. Hybrid imaging with positron emission tomography and computed tomography (PET/CT) may be a promising second-line modality in the reoperative setting, particularly when first-line modalities are discordant or inconclusive. Lastly, selective venous sampling should be reserved for challenging cases in which noninvasive modalities are negative or discordant. In the challenging population of reoperative patients with PHPT, a multimodality approach that utilizes the expertise of high-volume centers can accurately localize persistent or recurrent disease and enable curative parathyroidectomy.

Dual-Energy X-Ray Absorptiometry Compared to Computed Tomography for Visceral Adiposity Assessment Among Gastrointestinal and Pancreatic Cancer Survivors.

Dual-energy x-ray absorptiometry (DXA) for visceral adipose tissue (VAT) assessment is used as an alternative to computed tomography (CT) for research purposes in apparently healthy and clinical populations. It is unknown whether DXA is comparable to CT among cancer survivors, especially in cases where VAT assessment may be affected by treatment history and side effects and become more challenging to assess, such as a history of surgical gastrointestinal resection and/or ascites. The purpose of this study was to determine the level of agreement between DXA and CT when assessing VAT area and volume among cancer survivors. One hundred Gastrointestinal and pancreatic cancer survivors underwent abdominal and pelvis CT and whole-body DXA within 48 hours. Bland-Altman analysis revealed that in women and men, DXA VAT-area estimates were larger and smaller, respectively, and was consistently smaller in estimates for VAT-volume. Correlations from linear regression analysis revealed statistically significant positive correlations between measurement methods. Overall, while DXA VAT estimates are highly correlated with CT VAT estimates, DXA estimates show substantial bias which indicates the two methods are not interchangeable in this population. Further research is warranted with a larger, more homogeneous sample to develop better estimates of the bias.

Imágenes de adenomas paratiroideos ectópicos. Una revisión de la literatura / Imaging Ectopic Parathyroid Adenomas. A Literature Review

Objetivos: 1) Revisar la anatomía y epidemiología de los adenomas paratiroideos ectópicos (APE); 2) resumir el papel de las modalidades de imagen relevantes en su localización; y 3) revisar brevemente los enfoques quirúrgicos para los mismos. Métodos: Reseña literaria de artículos publicados en inglés desde 1984 hasta agosto de 2017. Resultados: El resumen de la literatura indica que la prevalencia de APE es de, aproximadamente, el 20 % en pacientes con hiperparatiroidismo primario que no han sido intervenidos quirúrgicamente, pero en pacientes reintervenidos es tan alta que alcanza el 66 %. Los APE pueden estar localizados en cualquier lugar, desde la bifurcación de la carótida hasta la ventana aortopulmonar. El ultrasonido tiene una agudeza diagnóstica limitada en su identificación, excepto para los que están localizados cerca de la glándula tiroides y al ligamento tirotímico. Requiere gran experiencia del operador. Si se comparan las técnicas de gammagrafía Sestamibi- 99mTc de fase dual, la imagen híbrida con tomografía computarizada de emisión de fotón simple (SPECT) y con tomografía computarizada (TC), la técnica SPECT/TC es superior a la gammagrafía planar o SPECT en la localización de los APE. La TC en cuatro dimensiones (4DTC) delinea con precisión las relaciones anatómicas importantes y es altamente sensible para la localización de los APE. Aunque la 4DTC requiere radiación, medio de contraste intravenoso yodado y experiencia del lector, provee buena información para detectar lesiones en varios sitios ectópicos y guiar el abordaje quirúrgico. Los APE frecuentemente requieren enfoques quirúrgicos alternativos. Se puede intentar una nueva paratiroidectomía en pacientes que han sido previamente sometidos a una exploración bilateral del cuello, por un cirujano experimentado, una vez que la lesión se localice mediante dos modalidades de imágenes. La remoción de la enfermedad no localizada requiere una exploración cuidadosa y sistemática de las localizaciones superiores e inferiores de las glándulas. Conclusión: Los APE plantean desafíos tanto para su localización como para la extirpación quirúrgica. Con el fin de obtener resultados óptimos se requiere contar con la experiencia de un alto número de pacientes y una atención multidisciplinaria.

Objective: (1) To review the anatomy and epidemiology of ectopic parathyroid adenomas (EPAs), (2) summarize the role of relevant imaging modalities in the localization of EPAs, and (3) briefly review surgical approaches for EPAs. Methods: Literature review of published English-language articles from 1984 through August 2017. Results: Summary of the literature indicates that the prevalence of EPA is approximately 20% in unexplored patients with primary hyperparathyroidism, but it is as high as 66% in re-operative patients. EPAs may be located anywhere from the carotid bifurcation to the aortopulmonary window. Ultrasound has limited accuracy in identifying EPAs except near the thyroid and thyrothymic ligament and requires expert experience from the user. Among dual-phase 99mTc sestamibi scintigraphy techniques, hybrid imaging with both singlephoton emission computed tomography (SPECT) and computed tomography (CT), (SPECT/CT) is superior to planar scintigraphy or SPECT alone at localizing EPAs. Four-dimensional computed tomography (4DCT) precisely delineates important anatomic relationships and is highly sensitive in localizing EPAs. Although 4DCT requires radiation, intravenous iodinated contrast, and reader experience, it is well-equipped to detect lesions at various ectopic sites and guide the surgical approach. EPAs frequently require alternative surgical approaches. Re-operative parathyroidectomy may be attempted in patients having previously undergone bilateral neck exploration by an experienced surgeon once the lesion is colocalized by 2 repeat imaging modalities. Removal of nonlocalized disease requires a careful and systematic exploration of superior and inferior gland locations. Conclusion: EPAs pose challenges during both localization and surgical removal. High-volume experience and multidisciplinary care are necessary for optimal outcomes.

IMAGING LOCALIZATION AND SURGICAL APPROACH IN THE MANAGEMENT OF ECTOPIC PARATHYROID ADENOMAS.

OBJECTIVE: ( 1) Review the anatomy and epidemiology of ectopic parathyroid adenomas (EPAs), ( 2) summarize the role of relevant imaging modalities in the localization of EPAs, and ( 3) characterize surgical approaches for various ectopic locations. METHODS: Literature review of published English-language articles from 1995 through August 2017. RESULTS: Summary of the literature indicates that the prevalence of EPA is approximately 20% in unexplored patients with primary hyperparathyroidism, but it is as high as 66% in re-operative patients. EPAs may be located anywhere from the carotid bifurcation to the aorto-pulmonary window. Ultrasound has limited accuracy in identifying EPAs except near the thyroid and thyrothymic ligament and requires expert experience from the user. Among dual-phase 99mTc sestamibi scintigraphy techniques, hybrid imaging with both single-photon emission computed tomography (SPECT) and computed tomography (CT) (SPECT/CT) is superior to planar scintigraphy or SPECT alone at localizing EPAs. Four-dimensional computed tomography (4DCT) precisely delineates important anatomic relationships and is highly sensitive in localizing EPAs. Although 4DCT requires radiation, intravenous iodinated contrast, and reader experience, it is well-equipped to detect lesions at various ectopic sites and guide the surgical approach. EPAs frequently require alternative surgical approaches. Re-operative parathyroidectomy may be attempted in patients having previously undergone bilateral neck exploration by an experienced surgeon once the lesion is colocalized by 2 repeat imaging modalities. Removal of nonlocalized disease requires a careful and systematic exploration of superior and inferior gland locations. CONCLUSION: EPAs pose challenges during both localization and surgical removal. High-volume experience and multidisciplinary care are necessary for optimal outcomes. ABBREVIATIONS: CT = computed tomography; 4DCT = 4-dimensional CT; EPA = ectopic parathyroid adenoma; EPG = ectopic parathyroid gland; PHPT = primary hyperparathyroidism; RLN = recurrent laryngeal nerve; SPECT = single-photon emission computed tomography; TE = tracheo-esophageal.

Perirenal Adiposity is Associated With Lower Progression-Free Survival From Ovarian Cancer.

OBJECTIVES: Abdominal obesity is linked with a higher risk of developing ovarian cancer. However, the link between abdominal obesity and survival after diagnosis of ovarian cancer is unknown. The purpose of this study was to determine the impact of abdominal obesity on progression-free survival in patients with ovarian cancer. METHODS: Among 258 patients, visceral and subcutaneous adipose tissue volume, along with perirenal adipose tissue thickness (a visceral adiposity proxy measure) was retrospectively measured from abdominal computed tomography (CT) scans obtained within 6 months of ovarian cancer diagnosis. Progression-free survival was computed using the Kaplan-Meier method and log-rank tests. Univariate and multivariate Cox proportional hazards analysis was used to determine relationships between measures of abdominal obesity and clinical variables in relation to progression-free survival. RESULTS: Patients with perirenal adipose tissue thickness greater than 5 mm(median) had lower rates of progression-free survival at 5 years compared with patients with perirenal adipose tissue thickness less than 5 mm (45.6% vs 53.8%, respectively). Perirenal adipose tissue thickness less than 5 mm was associated with lower rates of progression-free survival on multivariate analysis (hazard ratio = 1.37; 95% confidence interval, 1.03-1.82). There was no correlation with other metrics of abdominal adiposity on progression-free survival in univariate or multivariate analysis. CONCLUSIONS: Our data suggest that perirenal adipose, but not body mass index, visceral, or subcutaneous fat volume that were measured within 6 months from diagnosis, is associated with lower rates of progression-free survival in ovarian cancer.

Development and validation of a rapid and robust method to determine visceral adipose tissue volume using computed tomography images.

BACKGROUND: Visceral adiposity is a risk factor for many chronic diseases. Existing methods to quantify visceral adipose tissue volume using computed tomographic (CT) images often use a single slice, are manual, and are time consuming, making them impractical for large population studies. We developed and validated a method to accurately, rapidly, and robustly measure visceral adipose tissue volume using CT images. METHODS: In-house software, Medical Executable for the Efficient and Robust Quantification of Adipose Tissue (MEERQAT), was developed to calculate visceral adipose tissue volume using a series of CT images within a manually identified region of interest. To distinguish visceral and subcutaneous adipose tissue, ellipses are drawn through the rectus abdominis and transverse abdominis using manual and automatic processes. Visceral and subcutaneous adipose tissue volumes are calculated by counting the numbers of voxels corresponding to adipose tissue in the region of interest. MEERQAT's ellipse interpolation method was validated by comparing visceral adipose volume from 10 patients' CT scans with corresponding results from manually delineated scans. Accuracy of visceral adipose quantification was tested using a phantom consisting of animal fat and tissues. Robustness of the method was tested by determining intra-observer and inter-observer coefficients of variation (CV). RESULTS: The mean difference in visceral adipose tissue volume between manual and elliptical delineation methods was -0.54 ± 4.81%. In the phantom, our measurement differed from the known adipose volume by ≤ 7.5% for all scanning parameters. Mean inter-observer CV for visceral adipose tissue volume was 0.085, and mean intra-observer CV for visceral adipose tissue volume was 0.059. CONCLUSIONS: We have developed and validated a robust method of accurately and quickly determining visceral adipose tissue volume in any defined region of interest using CT imaging.