Browsing by Author "Stadler, Krystina L."
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- Computed Tomography and Magnetic Resonance Imaging Are Equivalent in Mensuration and Similarly Inaccurate in Grade and Type Predictability of Canine Intracranial GliomasStadler, Krystina L.; Ruth, Jeffrey D.; Pancotto, Theresa E.; Werre, Stephen R.; Rossmeisl, John H. Jr. (Frontiers, 2017-09-25)While magnetic resonance imaging (MRI) is the gold-standard imaging modality for diagnosis of intracranial neoplasia, computed tomography (CT) remains commonly used for diagnosis and therapeutic planning in veterinary medicine. Despite the routine use of both imaging modalities, comparison of CT and MRI has not been described in the canine patient. A retrospective study was performed to evaluate CT and MRI studies of 15 dogs with histologically confirmed glioma. Multiple lesion measurements were obtained, including two-dimensional and volumetric dimensions in pre-contrast and post-contrast images. Similar measurement techniques were compared between CT and MRI. The glioma type (astrocytoma or oligodendroglioma) and grade (high or low) were predicted on CT and MRI independently. With the exception of the comparison between CT pre-contrast volume to T2-weighted MRI volume, no other statistical differences between CT and MRI measurements were identified. Overall accuracy for tumor grade (high or low) was 46.7 and 53.3% for CT and MRI, respectively. For predicted tumor type, accuracy of CT was 53.3% and MRI and MRI 60%. Based on the results of this study, both CT and MRI contrast measurement techniques are considered equivalent options for lesion mensuration. Given the low-to-moderate predictability of CT and MRI in glioma diagnosis, histopathology remains necessary for accurate diagnosis of canine brain tumors.
- High-Frequency Irreversible Electroporation for Treatment of Primary Liver Cancer: A Proof-of-Principle Study in Canine Hepatocellular CarcinomaPartridge, Brittanie R.; O'Brien, Timothy J.; Lorenzo, Melvin F.; Coutermarsh-Ott, Sheryl; Barry, Sabrina L.; Stadler, Krystina L.; Muro, Noelle; Meyerhoeffer, Mitchell; Allen, Irving C.; Davalos, Rafael V.; Dervisis, Nikolaos G. (2020-03)Purpose: To determine the safety and feasibility of percutaneous high-frequency irreversible electroporation (HFIRE) for primary liver cancer and evaluate the HFIRE-induced local immune response. Materials and Methods: HFIRE therapy was delivered percutaneously in 3 canine patients with resectable hepatocellular carcinoma (HCC) in the absence of intraoperative paralytic agents or cardiac synchronization. Pre- and post-HFIRE biopsy samples were processed with histopathology and immunohistochemistry for CD3, CD4, CD8, and CD79a. Blood was collected on days 0, 2, and 4 for complete blood count and chemistry. Numeric models were developed to determine the treatment-specific lethal thresholds for malignant canine liver tissue and healthy porcine liver tissue. Results: HFIRE resulted in predictable ablation volumes as assessed by posttreatment CT. No detectable cardiac interference and minimal muscle contraction occurred during HFIRE. No clinically significant adverse events occurred secondary to HFIRE. Microscopically, a well-defined ablation zone surrounded by a reactive zone was evident in the majority of samples. This zone was composed primarily of maturing collagen interspersed with CD3(+)/CD4(-)/CD8(-) lymphocytes in a proinflammatory microenvironment. The average ablation volumes for the canine HCC patients and the healthy porcine tissue were 3.89 cm(3) +/- 0.74 and 1.56 cm(3) +/- 0.16, respectively (P = .03), and the respective average lethal thresholds were 710 V/cm +/- 28.2 and 957 V/cm +/- 24.4 V/cm (P = .0004). Conclusions: HFIRE can safely and effectively be delivered percutaneously, results in a predictable ablation volume, and is associated with lymphocytic tumor infiltration. This is the first step toward the use of HFIRE for treatment of unresectable liver tumors.
- Magnetization Transfer and Diffusion Tensor Imaging in Dogs with Intervertebral Disc HerniationShinn, Richard Levon (Virginia Tech, 2020-07-14)Background: Quantitative imaging surrogates of myelin and axonal integrity using magnetization transfer and diffusion tensor imaging may provide beneficial prognostic details on long-term post-surgical recovery in dogs with spinal cord injury (SCI) secondary to intervertebral disc herniation (IVDH). Hypothesis: Magnetization transfer ratio (MTR), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), and fractional anisotropy (FA) will be significantly different in patients with a successful outcome compared to patients with an unsuccessful outcome. Animals: 61 dogs with SCI secondary to IVDH were included in the final analysis. All dogs had to undergo surgical correction for SCI secondary to IVDH and be followed out for 12 weeks. Methods: Prospective cohort study. MTR, MD, AD, RD, and FA were calculated in dogs with SCI secondary to IVDH. A Wilcoxon signed-rank test was used to compare MTR, MD, AD, RD, and FA values between patients with a successful outcome and patients with an unsuccessful outcome. Statistical significance was set at p<0.05. For quantitative imaging surrogates with a significant relationship with outcome, a receiver operator characteristic (ROC) curve analysis was performed and the sensitivity and specificity for predicting successful outcome. Results: MTR (p=0.0013) was significantly lower in patients with a successful outcome compared to patients with an unsuccessful outcome. FA (p=0.435) was not significantly between groups. MD (p=0.0006), AD (p=0.0008) and RD (p=0.0002) were significantly higher in patients with a successful outcome compared to patients with an unsuccessful outcome. ROC curves were performed for MTR, AD and RD. If MTR was ≤ 53, AD ≥ 1.7 × 10-3mm2/s or RD ≥ 0.37 × 10-3 mm2/s, this resulted in a sensitivity of 96.3% and specificity of 100 in predicting a successful outcome. Conclusion and clinical relevance: MTR, MD, AD, and RD were helpful in predicting successful outcome in canine patients with surgically treated SCI secondary to IVDH. A larger cohort is needed for further evaluation.
- Magnetization transfer and diffusion tensor imaging in dogs with intervertebral disk herniationShinn, Richard L.; Pancotto, Theresa E.; Stadler, Krystina L.; Werre, Stephen R.; Rossmeisl, John H. Jr. (Wiley, 2020-10-02)Background: Quantitative magnetic resonance imaging (QMRI) techniques of magnetization transfer ratio (MTR) and diffusion tensor imaging (DTI) provide microstructural information about the spinal cord. Objective: Compare neurologic grades using the modified Frankel scale with MTR and DTI measurements in dogs with thoracolumbar intervertebral disk herniation (IVDH). Animals: Fifty-one dogs with thoracolumbar IVDH. Methods: Prospective cohort study. Quantitative MRI measurements of the spinal cord were obtained at the region of compression. A linear regression generalized estimating equations model was used to compare QMRI measurements between different neurological grades after adjusting for age, weight, duration of clinical signs, and lesion location. Results: Grade 5 (.79 × 10−3 mm2/s [median],.43−.91 [range]) and axial (1.47 × 10−3 mm2/s,.58−1.8) diffusivity were lower compared to grades 2 (1.003,.68−1.36; P =.02 and 1.81 × 10−3 mm2/s, 1.36−2.12; P <.001, respectively) and 3 (1.07 × 10−3 mm2/s,.77−1.5; P =.04 and 1.92 × 10−3 mm2/s, 1.83−2.37; P <.001, respectively). Compared to dogs with acute myelopathy, chronic myelopathy was associated with higher mean (1.02 × 10−3 mm2/s,.77−1.36 vs.83 × 10−3 mm2/s,.64−1.5; P =.03) and radial diffusivity (.75 × 10−3 mm2/s,.38−1.04 vs.44 × 10−3 mm2/s,.22−1.01; P =.008) and lower MTR (46.76, 31.8−56.43 vs. 54.4, 45.2−62.27; P =.004) and fractional anisotropy (.58,.4−0.75 vs.7,.46−.85; P =.02). Fractional anisotropy was lower in dogs with a T2-weighted intramedullary hyperintensity compared to those without (.7,.45−.85 vs.54,.4−.8; P =.01). Conclusion and Clinical Relevance: Mean diffusivity and AD could serve as surrogates of severity of spinal cord injury and are complementary to the clinical exam in dogs with thoracolumbar IVDH.