Nami Azar

Formulation and Characterization of Echogenic Lipid–Pluronic Nanobubbles

The advent of microbubble contrast agents has enhanced the capabilities of ultrasound as a medical imaging modality and stimulated innovative strategies for ultrasound-mediated drug and gene delivery. While the utilization of microbubbles as carrier vehicles has shown encouraging results in cancer therapy, their applicability has been limited by a large size which typically confines them to the vasculature. To enhance their multifunctional contrast and delivery capacity, it is critical to reduce bubble size to the nanometer range without reducing echogenicity. In this work, we present a novel strategy for formulation of nanosized, echogenic lipid bubbles by incorporating the surfactant Pluronic, a triblock copolymer of ethylene oxide copropylene oxide coethylene oxide into the formulation. Five Pluronics (L31, L61, L81, L64 and P85) with a range of molecular weights (M(w): 1100 to 4600 Da) were incorporated into the lipid shell either before or after lipid film hydration and before addition of perfluorocarbon gas. Results demonstrate that Pluronic-lipid interactions lead to a significantly reduced bubble size. Among the tested formulations, bubbles made with Pluronic L61 were the smallest with a mean hydrodynamic diameter of 207.9 +/- 74.7 nm compared to the 880.9 +/- 127.6 nm control bubbles. Pluronic L81 also significantly reduced bubble size to 406.8 +/- 21.0 nm. We conclude that Pluronic is effective in lipid bubble size control, and Pluronic M(w), hydrophilic-lipophilic balance (HLB), and Pluronic/lipid ratio are critical determinants of the bubble size. Most importantly, our results have shown that although the bubbles are nanosized, their stability and in vitro and in vivo echogenicity are not compromised. The resulting nanobubbles may be better suited for contrast enhanced tumor imaging and subsequent therapeutic delivery.

Noninvasive Characterization of In situ Forming Implants Using Diagnostic Ultrasound

In situ forming drug delivery systems provide a means by which a controlled release depot can be physically inserted into a target site without the use of surgery. The release rate of drugs from these systems is often related to the rate of implant formation. Currently, only a limited number of techniques are available to monitor phase inversion, and none of these methods can be used to visualize the process directly and noninvasively. In this study, diagnostic ultrasound was used to visualize and quantify the process of implant formation in a phase inversion based system both in vitro and in vivo. Concurrently, sodium fluorescein was used as a mock drug to evaluate the drug release profiles and correlate drug release and implant formation processes. Implants comprised of three different molecular weight poly(lactic-co-glycolic acid) (PLGA) polymers dissolved in 1-methyl-2-pyrrolidinone (NMP) were studied in vitro and a 29 kDa PLGA solution was evaluated in vivo. The implants were encapsulated in a 1% agarose tissue phantom for five days, or injected into a rat subcutaneously and evaluated for 48 h. Quantitative measurements of the gray-scale value (corresponding to the rate of implant formation), swelling, and precipitation were evaluated using image analysis techniques, showing that polymer molecular weight has a considerable effect on the swelling and formation of the in situ drug delivery depots. A linear correlation was also seen between the in vivo release and depot formation (R(2)=0.93). This study demonstrates, for the first time, that ultrasound can be used to noninvasively and nondestructively monitor and evaluate the phase inversion process of in situ forming drug delivery implants, and that the formation process can be directly related to the initial phase of drug release dependent on this formation.

Computed tomographic scan mapping of gastric wall perfusion and clinical implications

BACKGROUND Several postoperative gastrointestinal complications are attributed to ischemia. We herein evaluate the gastric wall perfusion using computed tomography (CT) scan perfusion index on trial to address the etiology of ischemic complication after sleeve gastrectomy. METHODS A retrospective study of 205 patients undergoing CT scan of the abdomen to evaluate the pattern of gastric vascular perfusion was performed. The perfusion index of the gastric mucosa was measured at 5 gastric points using CT perfusion scanning. RESULTS Gastric perfusion at the angle of His (AOH) (53.51 ± 14.38) was statistically significantly lower (P < .001) than that at the other gastric points studied: fundus, greater curvature, lesser curvature, incisura angularis, and mid gastric points (76.16 ± 15.21, 73.27 ± 16.55, 76.12 ± 16.12, and 75.24 ± 14.9, respectively). Gastric perfusion was significantly lower at all the gastric points (and especially so at the AOH) among obese patients (33 cases) compared with nonobese patients (18 cases). Gastric perfusion at all the points studied showed a decrease as the body mass index increases. Hypertensive patients had a better gastric perfusion compared with nonhypertensive patients. CONCLUSIONS Gastric wall perfusion is statistically significantly decreased at the AOH and gastric fundus compared with perfusion at other gastric points. Gastric perfusion at all the gastric points studied decreased with the increase in body mass index. Gastric leakage in obese patients following sleeve gastrectomy could be attributed to a decrease in the blood supply at AOH.

Inflammatory Pseudotumor of the Spleen: Review of clinical presentation and diagnostic methods

We describe a 91-year-old woman with a clinical history of invasive ductal carcinoma of the breast diagnosed in 1991 who was admitted because of dizziness, poor appetite, and some swelling and tenderness over her cheeks. The patients initial work up revealed a 5-cm well-demarcated hypodense solid lesion in her spleen with abnormally intense uptake on PET/CT scan raising suspicion for malignancy i.e. breast metastasis versus lymphoma. Further review demonstrated the presence of this splenic lesion, though slightly smaller, on a CT scan from ten years earlier (2000). An ultrasonographic guided core needle splenic biopsy was performed and the pathology result revealed histological findings compatible with inflammatory pseudotumor of the spleen. As a result, unnecessary splenectomy was avoided.

Percutaneous computed tomography guided cryoablation of the celiac plexus as an alternative treatment for intractable pain caused by pancreatic cancer

Computed Tomography (CT)-guided percutaneous cryoablation was performed in a 43-year-old patient with intractable epigastric abdominal pain caused by advanced adenocarcinoma of the pancreas and extensive celiac trunk involvement. Initial treatment with celiac plexus nerve neurolysis using local ethanol injection was unsuccessful. A 17-gauge 17-cm cryoablation probe (Galil Medical Inc. Plymouth Meeting, PA) was placed into the expected location of the celiac plexus through a left paraspinal approach under CT guidance and two cycles of freeze-thaw were performed. Patients pain decreased from 10 of 10 (subjective pain scoring using a visual analog scale; VAS; 0-10) to 3. No post-procedure complication was observed. His pain has remained stable after 6 months of follow up. Percutaneous cryoablation appears to be an effective alternative to neurolytic celiac plexus block for palliative treatment of celiac plexus involvement. Further study with larger number of patients is needed to evaluate the safety and efficacy.

The Radiologist Will See You Now: Patients’ Perceptions of an Outpatient Interventional Clinic

Patient satisfaction is becoming an increasingly important part of Americas healthcare system. Patient satisfaction is now a metric assessed for value-based incentive payments by the Center for Medicare and Medicaid Services, and the healthcare market is becoming increasingly consumer-driven as patients are provided with more options regarding where they receive care as well as improved access to medical information. Radiologists, while less involved with direct patient care than other medical specialties, are not immune to the changing medical landscape and need to adapt to a progressively value- and patient-oriented healthcare system. At our institution, first-year radiology residents take an active role in our outpatient interventional radiology clinic by performing clinical histories and physical exams in a dedicated radiology clinic examination rooms. Stressing the various opportunities for patient interaction and the potential benefits of patient- centered radiology in the evolving healthcare system may increase its perceived value among both radiology residents as well as practicing radiologists. ​Directly engaging patients may be unfamiliar territory for the practicing radiologist and an unexpected prospect for current residents, but available data suggests that patients do value direct interaction with radiologists during the course of their care.

Ultrasonographic thyroid findings suspicious for malignancy

Asymptomatic incidental thyroid nodules (thyroid incidentalomas) are found in up to a third of the adult population. There is notable overlap in the sonographic appearance of benign and malignant thyroid nodules. This paper provides a brief review of the ultrasound findings of thyroid nodules that are suspicious for malignancy with pathologic correlates. We then discuss the standard approach to a fine needle aspiration biopsy of a thyroid nodule at our institution. Finally, we review specific diagnostic challenges in image guided fine needle aspiration biopsies. Diagn. Cytopathol. 2013;41:1107–1114.

Committee I: Indications for pulmonary cytology sampling methods

The Papanicolaou Society of Cytopathology has developed a set of guidelines for pulmonary cytology including indications for bronchial brushings, washings and endobronchial ultrasound‐guided fine needle aspiration, technical recommendations for cytologic sampling, recommended terminology and classification scheme, recommendations for ancillary testing and recommendations for postcytologic diagnosis management and follow‐up. All recommendation documents are based on the expertise of the authors, extensive literature review and feedback from presentations at national and international conferences. This document selectively presents the results of these discussions. The present document summarizes the recommendations for clinical and imaging evaluation of pulmonary lesions along with the indications for cytologic studies regarding these abnormalities. Preprocedural requirements regarding brushing, washing and needle aspiration procedures are discussed also. Diagn. Cytopathol. 2016;44:1010–1023.

Vicarious urinary excretion of iodinated contrast in a Crohn's patient

Vicarious renal excretion of iodinated contrast introduced into the bowel is a known phenomenon that has rarely been reported. In clinical settings like Crohns disease in which evaluation for recto-vesical fistula is frequently requested, vicarious excretion can cause misapprehension and error in diagnosis. We present a case of Crohns disease in which gastrografin enema was performed to evaluate for fistula and initial interpretation was mistakenly positive, however, simple methods of elucidation were utilized to prevent error in diagnosis.

Evolving clinical applications of contrast-enhanced ultrasound (CEUS) in the abdominal aorta

Ultrasound (US) represents the initial modality in the workup of abdominal aortic pathology based on the plethora of advantages including widespread availability, low cost, safety profile and repeatability. However, US has inherent limitations including limited spatial information of pathologic processes to neighboring structures, lower sensitivity to slow blood flow and aortic luminal irregularities. For evaluation of aortic pathology angiography has long been considered the gold standard. Non-invasive cross-sectional imaging techniques like computed tomography angiography (CTA) and magnetic resonance angiography (MRA) have gradually replaced interventional angiography for the evaluation of aorta, currently being regarded as the diagnostic imaging modalities of choice for diagnosis of virtually every aortic disease. Interventional angiography is currently primarily performed for treatment purposes of aortic pathology. The introduction of microbubbles as ultrasonographic contrast agents has rendered contrast-enhanced ultrasound (CEUS) an evolving valuable complementary technique with markedly increased diagnostic accuracy for certain aortic applications. CEUS is characterized by the potential to be performed in patients with impaired renal function. Due to its superior spatial and temporal resolution, ability for prolonged scanning and dynamic and real-time imaging, it provides clinically significant additional information compared to the standard Duplex US. The purpose of this paper is to discuss the currently available literature regarding abdominal aortic applications of CEUS, briefly elaborate on CEUS technique and safety and present cases in order to illustrate the added value in aortic pathologies. Conditions discussed include abdominal aortic aneurysm (AAA), aneurysm rupture, aneurysm surveillance after endovascular repair, dissection and aortitis.