Sanaz Javadi

Preclinical Assessment of a 980-nm Diode Laser Ablation System in a Large Animal Tumor Model

PURPOSE To characterize the performance of a 980-nm diode laser ablation system in an in vivo tumor model. MATERIALS AND METHODS This study was approved by the institutional animal care and use committee. The ablation system consisted of a 15-W, 980-nm diode laser, flexible diffusing-tipped fiber optic, and 17-gauge internally cooled catheter. Ten immunosuppressed dogs were inoculated subcutaneously with canine-transmissible venereal tumor fragments in eight dorsal locations. Laser ablations were performed at 79 sites where inoculations were successful (99%) at powers of 10 W, 12.5 W, and 15 W, with exposure times between 60 and 180 seconds. In 20 cases, multiple overlapping ablations were performed. After the dogs were euthanized, the tumors were harvested, sectioned along the applicator tract, measured, and photographed. Measurements of ablation zone were performed on gross specimen. Histopathology and viability staining was performed with hematoxylin and eosin and nicotinamide adenine dinucleotide hydrogen staining. RESULTS Gross pathologic examination confirmed a well circumscribed ablation zone with sharp boundaries between thermally ablated tumor in the center surrounded by viable tumor tissue. When a single applicator was used, the greatest ablation diameters ranged from 12 mm at the lowest dose (10 W, 60 seconds) to 26 mm at the highest dose (15 W, 180 seconds). Multiple applicators created ablation zones as large as 42 mm in greatest diameter (with the lasers operating at 15 W for 120 seconds). CONCLUSIONS The new 980-nm diode laser and internally cooled applicator effectively create large ellipsoid thermal ablations in less than 3 minutes.

Adrenal ganglioneuroma: Features and outcomes of 27 cases at a referral cancer centre

Adrenal ganglioneuroma (AGN) is a rare neurogenic tumour that can mimic other adrenal neoplasms. Limited information, mostly derived from small cases series, is available for AGN.

Real-time magnetic resonance imaging-guided cryoablation of small renal tumors at 1.5 T

ObjectivesReal-time magnetic resonance imaging (MRI)–guided cryoablation has been investigated in open MRI systems with low magnetic fields (0.2–0.5 T). More advanced imaging techniques and faster imaging rates are possible at higher magnetic fields, which often require a closed-bore magnet design. However, there is very little experience with real-time interventions in closed-bore 1.5-T MRI units. Herein, we report our initial experience with real-time MRI-guided cryoablation of small renal tumors using a prototype balanced steady-state free precession imaging sequence in a closed-bore 1.5-T MRI system. Materials and MethodsFrom August 2008 to April 2012, 18 patients underwent MRI-guided cryoablation of small renal tumors. A 1.5-T cylindrical MRI scanner with a 125 cm × 70 cm bore and a prototype balanced steady-state free precession sequence (BEAT interactive real-time tip tracking) were used to guide the placement of 17-gauge cryoprobes in real time. Ice ball formation was monitored every 3 minutes in 1 or more imaging planes. Each ablation consisted of 2 freeze-thaw cycles. Contrast-enhanced MRI was performed after the second active thaw period. Follow-up consisted of clinical evaluation and renal protocol computed tomography (CT) or MRI performed at 1, 6, 12, 18, and 24 months and annually thereafter. ResultsDuring the study period, we successfully ablated 18 tumors in 18 patients in 18 sessions. The mean tumor size was 2.2 cm (median, 2 cm; range, 1.2–4.4 cm). The number of cryoprobes used per patient was determined based on tumor size. The mean number of cryoprobes used per patient was 3 (median, 3 cryoprobes; range, 2–4 cryoprobes). Fifty-six cryoprobes, 9 biopsy needles, and 2 hydrodissection needles were successfully placed under real-time MRI guidance using BEAT interactive real-time tip tracking sequence. Hydrodissection under MRI guidance was successfully performed in 4 patients. In each patient, contrast-enhanced MRI performed after the second active thaw period revealed a sharply defined avascular zone surrounding the targeted tumor, which confirmed complete ablation of the tumor with adequate margins. Although contrast media slowly accumulated in the targeted tumor in 9 patients immediately after the procedure, follow-up imaging studies performed at a mean of 16.7 months revealed no contrast enhancement within the ablation zone in these patients. Disease-specific, metastasis-free, and local recurrence-free survival rates were all 100%. ConclusionsReal-time placement and manipulation of cryoprobes during MRI-guided cryoablation of small renal tumors in a closed-bore, high–magnetic field scanner are feasible. Technical and clinical success rates are similar to those of patients who undergo CT-guided radiofrequency ablation or cryoablation of small renal tumors. Our findings suggest that MRI-guided ablation has several advantages over CT-guided ablation, including real-time guidance for probe placement, multiplanar imaging, exquisite soft tissue contrast, and lack of ionizing radiation.

Characterization of Contrast Enhancement in the Ablation Zone Immediately after Radiofrequency Ablation of Renal Tumors

PURPOSE To characterize the degree of contrast enhancement within the ablation zone immediately after radiofrequency (RF) ablation of renal tumors. MATERIALS AND METHODS Patients with renal tumors treated with percutaneous RF ablation at one institution between January 2004 and October 2007 were retrospectively reviewed. For each tumor, computed tomography (CT) density measurements were made at four phases (noncontrast, arterial phase, parenchymal phase, and excretory phase) in each of four CT examinations (before ablation, day 0, 1 month, and 6 months). RESULTS A total of 36 renal tumors in 34 patients were treated with CT-guided RF ablation in 35 sessions. Before RF ablation, all tumors exhibited enhancement after intravenous administration of contrast material. The peak density was reached during the parenchymal phase, with a partial washout of contrast agent in the excretory phase. On CT images acquired immediately after RF ablation (day 0), 28 of the 36 ablated tumors (78%) exhibited clinically significant homogeneous enhancement (ie, density change >10 HU) within the ablation zone. However, contrast-enhanced CT studies performed at 1 and 6 months revealed no clinically significant enhancements in any of the 36 treated tumors (mean density changes of 4 HU at 1 month and 3 HU at 6 months). CONCLUSIONS Contrast-enhanced CT studies revealed a mild, temporary homogenous contrast enhancement of the ablation zone immediately after RF ablation of renal tumors, which should not be mistaken for a residual, unablated tumor. This enhancement in the ablation zone eventually disappears in follow-up contrast-enhanced CT studies.

Effects of near-infrared laser irradiation of biodegradable microspheres containing hollow gold nanospheres and paclitaxel administered intraarterially in a rabbit liver tumor model

PURPOSE To evaluate the effects of near-infrared (NIR) laser irradiation of microspheres (MS) containing hollow gold nanospheres (HAuNS) and paclitaxel (PTX) administered intraarterially in an animal model. MATERIALS AND METHODS For the ex vivo experiments, VX2 tumor-bearing rabbits underwent administration of MS-HAuNS or MS via the hepatic artery (HA). The animals were killed, the liver tumors were subjected to NIR irradiation, and temperature changes were estimated with magnetic resonance (MR) imaging. For the in vivo study, VX2 tumor-bearing rabbits were randomly assigned to three groups: MS-HAuNS-PTX-plus-NIR, MS-HAuNS-PTX, and saline-plus-NIR. Laser irradiation was delivered at 1 hour and at 3 days after administration of saline or MS-HAuNS-PTX via the HA. Animals were euthanized, and tumors were analyzed for necrosis and apoptosis. Plasma samples were collected from the MS-HAuNS-PTX-plus-NIR animals for PTX analysis. RESULTS Ex vivo experiments showed intratumoral heating in animals that received MS-HAuNS but no temperature change in animals that received MS. Animals treated with MS-HAuNS-PTX-plus-NIR showed a transient increase in plasma PTX levels after each NIR irradiation and significantly greater tumor necrosis than animals that received MS-HAuNS-PTX or saline-plus-NIR (44.9% vs 13.8% or 23.7%; P < .0001). The mean apoptotic index in the MS-HAuNS-PTX-plus-NIR group (5.01 ± 1.66) was significantly higher than the mean apoptotic index in the MS-HAuNS-PTX (2.99 ± 0.97) or saline-plus-NIR (1.96 ± 0.40) groups (P = .0013). CONCLUSIONS NIR laser irradiation after MS-HAuNS-PTX administration results in intratumoral heating and increases the efficacy of treatment. Further studies are required to evaluate the optimal laser settings to maximize therapeutic efficacy.

Development of a large animal model of cirrhosis and portal hypertension using hepatic transarterial embolization: A study in swine

PURPOSE To develop a clinically relevant porcine model of liver cirrhosis with portal hypertension by means of hepatic transarterial embolization. MATERIALS AND METHODS Institutional animal care and use committee approval was obtained for all experiments. Pigs received transcatheter arterial infusion of a 3:1 mixture of iodized oil and ethanol into the hepatic artery in volumes of 16 mL in group 1 (n = 4), 28 mL in group 2 (n = 4), and 40 mL in group 3 (n = 4) with intent of bilobar distribution. Hepatic venous pressure gradient (HVPG) measurement, liver function tests, and volumetry were performed at baseline, at 2 weeks, and before necropsy. RESULTS Cirrhosis was successfully induced in three animals that received 16 mL of the embolic mixture and in all four animals that received 28 mL. The animals in the 40-mL group did not recover from the procedure and were euthanized within 48 h. Increases in HVPG after 6-8 weeks versus baseline reached statistical significance (P < .05). Correlation between degree of fibrosis and volume of embolic agent did not reach statistical significance, but there was a trend toward increased fibrosis in the 28-mL group compared with the 16-mL group. CONCLUSIONS Transcatheter hepatic arterial embolization can be used to create a reliable and reproducible porcine model of liver cirrhosis and portal hypertension.

Mediastinal, Hilar, and Pleural Image-Guided Biopsy: Current Practice and Techniques

Cross-sectional imaging of the chest with computed tomography (CT), magnetic resonance imaging, and at times, ultrasonography exquisitely delineates mediastinal, hilar, and pleural pathologies. The treatment of patients with these pathologies is often based on the results of image-guided biopsies. CT and ultrasonography have been used successfully for targeting and sampling mediastinal, hilar, and pleural masses, with high sensitivity and near-perfect specificity. These procedures are performed by interventional radiologists in an outpatient setting with local anesthesia and conscious sedation. Major complications are rare, and the minor complications seen are easily managed. Minimally invasive, image-guided biopsy often obviates the need for more invasive procedures such as thoracoscopy or mediastinoscopy.

Ovarian Cancer, the Revised FIGO Staging System, and the Role of Imaging.

OBJECTIVE It is now recognized that ovarian cancer includes a heterogeneous group of malignant epithelial tumors originating from the ovaries, fallopian tubes, or peritoneum. This development has prompted the International Federation of Gynecology and Obstetrics (FIGO) to issue a revised staging system that can provide prognostic information and guidance on personalized management of ovarian cancer. CONCLUSION We review the epidemiology of ovarian cancer, the new FIGO staging system, and the role of imaging in the assessment, staging, and follow-up of ovarian cancer.

Clinical and Radiologic Features of Pheochromocytoma/Ganglioneuroma Composite Tumors: A Case Series with Comparative Analysis

OBJECTIVE To describe and compare the clinical, biochemical, radiologic, and pathologic features of adrenal pheochromocytoma-ganglioneuroma (PC-GN) composites with the features of isolated pheochromocytomas (PCs) and adrenal ganglioneuromas (AGNs). METHODS We reviewed data for PC-GN composite cases seen at a single tertiary center between 1993 and 2012 and compared them with cases of isolated AGN and relatively similar median-size PCs. RESULTS Nine PC-GN composites were included. The median age at diagnosis was 52 years (range, 28 to 83 years) for PC-GN compared with 55 years (range, 24 to 78 years) for PC patients and 40 years (range, 18 to 64 years) for AGN patients. Similar to PCs, all PC-GN composites were associated with catecholamine overproduction, whereas AGNs were nonfunctioning. On pathology, the median tumor sizes were 7 cm (range, 2.5 to 13 cm) for PC-GN tumors, 6.5 cm (range, 3.5 to 7 cm) for PCs, and 8 cm (range, 3.2 to 20 cm) for AGNs. On computed tomography (CT) imaging, PC-GN composites and PCs were heterogeneous, with both having significantly higher postcontrast density values than AGNs, which typically looked homogeneous and had a progressive enhancement pattern without contrast washout in most cases. CONCLUSION The presence of a PC component significantly increases tumor heterogeneity and postcontrast density values. CT imaging could be very helpful in distinguishing AGNs from both PC-GN and PC tumors, but only pathologic examination can yield the diagnosis. Clinically and radiologically, PC-GN composites are indistinguishable from PCs and need to be managed similarly.

Gastroduodenal artery recanalization after transcatheter fibered coil embolization for prevention of hepaticoenteric flow: incidence and predisposing technical factors in 142 patients.

Background Prophylactic occlusion of extrahepatic vessels prior to radioembolization or chemotherapy infusion is an effective method to prevent gastrointestinal complications. Unfortunately, vascular recanalization can occur. Purpose To retrospectively determine the rate and technical factors associated with gastroduodenal artery (GDA) recanalization after transcatheter occlusion with fibered coils. Material and Methods Patients with hepatic malignancy who underwent fibered coil occlusion of the GDA origin for radioembolization or hepatic arterial chemotherapy infusion with at least one subsequent hepatic angiogram between March 2006 and January 2011 were included. One hundred and forty-two patients (men, 71; women, 71) met study criteria. Hepatic arteriograms were reviewed to determine the frequency of arterial recanalization. Additional parameters included: patients’ demographics, GDA diameter, length of coil pack, distance between GDA origin and most cephalad coil, persistent flow at the conclusion of the initial GDA occlusion procedure, platelet count, and international normalized ratio (INR). Chi-square test and pooled t-test were used to compare the two groups. Prospective multivariate analysis was performed with a logistic regression model. Results Twenty-nine of 142 patients (20.4%) experienced GDA recanalization. The distance between the GDA origin and most cephalad coil was significantly greater in the recanalization group than in the non-recanalization group (9.6 mm vs. 12.6 mm, P = 0.01). A prospective multivariate analysis established that the further the coil was from the origin the more likely the GDA was to recanalize. The two groups did not differ on the basis of any other factors examined. Conclusion GDA origin recanalization after fibered coil occlusion is common. The distance between the GDA origin and most cephalad coil appears to be a predisposing factor for recanalization. Familiarity with this phenomenon is beneficial to reduce the likelihood of gastrointestinal tract complications during hepatic locoregional therapy.