Normalized Dual-Energy Iodine Ratio Best Differentiates Renal Cell Carcinoma Subtypes Among Quantitative Imaging Biomarkers From Perfusion CT and Dual-Energy CT.

OBJECTIVE. The objective of our study was to assess and compare the diagnostic accuracy of perfusion CT (PCT) and dual-energy CT (DECT) in differentiating clear cell renal cell carcinoma (ccRCC) from non-ccRCC. MATERIALS AND METHODS. This retrospective study included 51 patients with 52 renal cell carcinomas (RCCs) (36 ccRCCs and 16 non-ccRCCs) who underwent both PCT and DECT before surgery or biopsy between January 2014 and December 2018. Three independent readers measured blood flow, blood volume (BV), and permeability using PCT and iodine concentration (IC) and iodine ratio using DECT. Interreader agreement was calculated using the intraclass correlation coefficient (ICC). Multivariable logistic regression analysis was performed to assess PCT and DECT models. Size-specific dose estimates of the two methods were compared. RESULTS. BV (ICC, 0.93) and iodine ratio (ICC, 0.85) were the most reproducible parameters. Both PCT and DECT were significant models (p < 0.05, all readers) for differentiating ccRCC from non-ccRCC. There was no significant difference in diagnostic accuracy between PCT and DECT (p > 0.05). BV and iodine ratio were independent predictors of nonccRCC (p < 0.05). However, the mean size-specific dose estimate was 16 times lower with DECT than with PCT (p < 0.001). The AUC of iodine ratio was 0.95, and sensitivity, specificity, and accuracy with an iodine ratio cutoff of 63.72% was 0.90, 0.86, and 0.87, respectively. CONCLUSION. PCT and DECT had comparable and high diagnostic accuracy in differentiating RCC subtypes; however, because of the significantly lower radiation dose of DECT, iodine ratio may be used as the best independent predictor.

Iodine Parameters in Triple-Bolus Dual-Energy CT Correlate With Perfusion CT Biomarkers of Angiogenesis in Renal Cell Carcinoma.

OBJECTIVE. The purpose of this study is to determine the degree of the relationship between perfusion CT (PCT) parameters and iodine concentration metrics derived from triple-bolus dual-energy CT (DECT) and to compare the radiation dose delivered. SUBJECTS AND METHODS. This single-center prospective study was conducted from October 2015 to September 2017. Twenty-three consenting adults (15 men and eight women; mean [± SD] age, 56 ± 13 years [range, 25-78 years]) with renal cell carcinomas underwent consecutive PCT and triple-bolus DECT examinations. Triple-bolus DECT consisted of synchronous corticomedullary, nephrographic, and delayed phase scans acquired using a dual-source DECT scanner. Two readers independently analyzed blood flow, blood volume, and permeability, as measured by PCT, and iodine density and iodine ratio, as measured by triple-bolus DECT. Size-specific dose estimates were calculated for both groups. RESULTS. Interreader agreement was good for permeability (intraclass correlation coefficient [ICC] =.812) and blood flow (ICC = 0.849) and excellent for blood volume (ICC = 0.956), iodine density (ICC = 0.961), and iodine ratio (ICC = 0.956). Very strong positive correlations were found between blood volume and iodine density (p < 0.001) and between blood volume and iodine ratio (p < 0.001). Strong positive correlations were found between blood flow and iodine density (p < 0.001) and between blood flow and iodine ratio (p < 0.001). The correlations between permeability and iodine density (p = 0.01) and between permeability and iodine ratio (p = 0.02) were moderate. The mean size-specific dose estimate of triple-bolus DECT was approximately 15 times lower than that of PCT (p < 0.001). CONCLUSION. Quantitative iodine metrics derived from triple-bolus DECT showed significant correlation with CT parameters in renal cell carcinoma, with a significantly lower radiation dose.

Single-Acquisition Triple-Bolus Dual-Energy CT Protocol for Comprehensive Evaluation of Renal Masses: A Single-Center Randomized Noninferiority Trial.

OBJECTIVE: The primary objective of this study was to compare triple-bolus dual-energy CT (DECT) against standard triple-phase MDCT in terms of appropriateness of patient treatment. SUBJECTS AND METHODS: One hundred twenty-four patients with suspected renal masses seen at ultrasound were randomized into triple-bolus DECT and triple-phase MDCT groups. Patients in the triple-bolus DECT group underwent synchronous corticomedullary nephrographic delayed-phase triple-bolus DECT. In the triple-phase MDCT group, single-energy triple-phase scans were acquired after an unenhanced scan. The primary outcome was appropriateness of treatment received at 1 year. The predefined noninferiority limit was 10%. Histopathologic analysis or follow-up confirmed the benign or malignant nature of the masses. Diagnostic accuracy to differentiate benign from malignant masses was calculated. Size-specific dose estimates were compared. RESULTS: After excluding six patients, 118 patients were analyzed (62 triple-bolus DECT; 56 triple-phase MDCT). Treatment appropriateness was not significantly different (p = 0.9397) between the two groups (61/62 [98.39%; 95% CI, 95.26-101.52%] for triple-bolus DECT vs 55/56 [98.21%; 95% CI, 94.74-101.68%] for triple-phase MDCT). The absolute difference was 0.18% (95% CI, -4.48% to 4.84%). Both techniques had similar diagnostic accuracy (sensitivity, 98.25% vs 96.67%; specificity, 98.17% vs 97.97%). The mean (± SD) size-specific dose estimate was significantly lower for triple-bolus DECT than for triple-phase MDCT (19.02 ± 4.07 vs 57.04 ± 15.17 mGy; p < 0.0001). CONCLUSION: Single-acquisition triple-bolus DECT is noninferior to triple-phase MDCT, with similar diagnostic accuracy but delivering significantly less radiation.

Clinico-radiological review of peripheral entrapment neuropathies - Part 2 Lower limb.

PURPOSE: This review discusses the relevant anatomy, etiopathogenesis, current notions in clinical and imaging features as well as management outline of lower limb entrapment neuropathies. METHODS: The review is based on critical analysis of the current literature as well as our experience in dealing with entrapment neuropathies of the lower limb. RESULTS: The complex anatomical network of nerves supplying the lower extremities are prone to entrapment by a heterogenous group of etiologies. This leads to diverse clinical manifestations making them difficult to diagnose with traditional methods such as clinical examination and electrodiagnostic studies. Moreover, some of these may mimic other common conditions such as disc pain or fibromyalgia leading to delay in diagnosis and increasing morbidity. Addition of imaging improves the diagnostic accuracy and also help in correct treatment of these entities. Magnetic resonance imaging is very useful for deeply situated nerves in pelvis and thigh while ultrasound is well validated for superficial entrapment neuropathies. CONCLUSION: The rapidly changing concepts in these conditions accompanied by the advances in imaging has made it essential for a clinical radiologist to be well-informed with the current best practices.

Clinico-radiological review of peripheral entrapment neuropathies - Part 1 upper limb.

PURPOSE: This article aims to review the pertinent anatomy, etiopathogenesis, current clinical and radiological concepts and principles of management in case of upper limb entrapment neuropathies. METHODS: The review is based on critical analysis of the existing literature as well as our experience in dealing with entrapment neuropathies. RESULTS: Entrapment neuropathies of the upper limb peripheral nerves are common conditions that are often misdiagnosed because of their varying clinical presentations and lack of standardized diagnostic methods. Clinical assessment and electrodiagnostic studies have been the mainstay; however, imaging techniques have provided newer insights into the pathophysiology of these entities, leading to a paradigm shift in their diagnosis and management. The current best practice protocols for entrapment syndromes are constantly evolving with increasing emphasis on the role high-resolution ultrasound and magnetic resonance imaging. Many imaging criteria are described and we have tried to present the most validated measurements for diagnosing entrapment neuropathies. CONCLUSION: It is imperative for a clinical radiologist to be familiar with the etiopathogenesis and clinical features of these conditions, in addition to being thorough with the anatomy and the latest imaging strategies.

Unusual pseudocyst in a wandering spleen.

Pseudocysts of the spleen are rare, generally asymptomatic lesions developing secondary to trauma, infection or infarction. When symptomatic, they typically present as non-specific pain in the left hypochondrium, with or without a palpable lump on clinical examination. However, these conventions fail when they occur in a wandering spleen, making imaging critically important. This report describes an unusual case of a 50-year-old who presented with a large cystic mass in a pelvic spleen; imaging facilitated a successful splenectomy and subsequent histopathology revealed a pseudocyst in a wandering spleen.

Spontaneous Rupture of an Esophageal Mucocele Into the Airway.

An esophageal mucocele is an uncommon complication after exclusion surgery of the thoracic esophagus. Although asymptomatic in most cases, it can progressively enlarge in size to cause symptoms requiring intervention. Occasionally, spontaneous decompression of its contents into the neck, mediastinum, peritoneal cavity, or tracheobronchial tree can occur, leading to potentially serious complications. We present a case of symptomatic esophageal mucocele after esophageal exclusion, complicated by the formation of an esophagobronchial fistula.

Complications of endoscopic retrograde cholangiopancreatography: an imaging review.

Endoscopic retrograde cholangiopancreatography (ERCP) has currently become an inseparable tool in the gastroenterologist's armamentarium for treatment of pancreaticobiliary disorders. Given the increase in number of therapeutic ERCP procedures today, the need for prompt and correct diagnosis of its complications is pivotal. This review discusses the mechanisms, risk factors, imaging findings and general management aspects of common and rare complications of ERCP. Furthermore, the review elaborates on imaging indications, recommended protocol and normal imaging findings post ERCP.

Diffusion weighted imaging in gynecological malignancies - present and future.

The management of gynaecological malignancies has undergone a significant change in recent years with our improved understanding of cancer biogenetics, development of new treatment regimens and enhanced screening. Due to the rapid blooming of newer methods and techniques in gynaecology, surgery and oncology the scope and the role of imaging has also widened. Functional imaging in the form of diffusion weighted imaging (DWI) has been recently found to be very useful in assessing various tumours. Its ability to identify changes in the molecular level has dramatically changed the diagnostic approach of radiologists which was solely based on morphological criteria. It can improve the diagnostic accuracy of conventional magnetic resonance imaging, lend a hand in assessing tumour response to treatment regimens and detect tumour recurrence with better spatial resolution, negative radiation and diagnostic accuracy compared to positron emission tomography scan. The ability to quantify the diffusion has also lead to potential prediction of tumour aggressiveness and grade which directly correlate with the patient prognosis and management. Hence, it has become imperative for a radiologist to understand the concepts of DWI and its present and evolving role. In this article we present a brief description of the basics of DWI followed by its role in evaluation of female gynaecological malignancies.