Robot-assisted screw fixation in a cadaver utilizing magnetic resonance imaging-based synthetic computed tomography: toward radiation-free spine surgery. Illustrative case.

BACKGROUND: Synthetic computed tomography (sCT) can be created from magnetic resonance imaging (MRI) utilizing newer software. sCT is yet to be explored as a possible alternative to routine CT (rCT). In this study, rCT scans and MRI-derived sCT scans were obtained on a cadaver. Morphometric analysis was performed comparing the 2 scans. The ExcelsiusGPS robot was used to place lumbosacral screws with both rCT and sCT images. OBSERVATIONS: In total, 14 screws were placed. All screws were grade A on the Gertzbein-Robbins scale. The mean surface distance difference between rCT and sCT on a reconstructed software model was -0.02 ± 0.05 mm, the mean absolute surface distance was 0.24 ± 0.05 mm, and the mean absolute error of radiodensity was 92.88 ± 10.53 HU. The overall mean tip distance for the sCT versus rCT was 1.74 ± 1.1 versus 2.36 ± 1.6 mm (p = 0.24); mean tail distance for the sCT versus rCT was 1.93 ± 0.88 versus 2.81 ± 1.03 mm (p = 0.07); and mean angular deviation for the sCT versus rCT was 3.2° ± 2.05° versus 4.04°± 2.71° (p = 0.53). LESSONS: MRI-based sCT yielded results comparable to those of rCT in both morphometric analysis and robot-assisted lumbosacral screw placement in a cadaver study.

Transthoracic fine-needle aspiration diagnosis of solid, subsolid, and partially calcified lung nodules: A retrospective study from a single academic center.

BACKGROUND: The large-scale National Lung Cancer Screening Trial demonstrated an increased detection of early-stage lung cancers using low-dose computed tomography scan in the screening population. It also demonstrated a 20% reduction of lung cancer-related deaths in these patients. AIMS: Although both solid and subsolid lung nodules are evaluated in studies, subsolid and partially calcified lung nodules are often overlooked. MATERIALS AND METHODS: We reviewed transthoracic fine-needle aspiration (FNA) cases from lung nodule patients in our clinics and correlated cytological diagnoses with radiologic characteristics of lesions. A computer search of the pathology archive was performed over a period of 12 months for transthoracic FNAs, including both CT- and ultrasound-guided biopsies. RESULTS: A total of 111 lung nodule cases were identified. Lesions were divided into three categories: solid, subsolid, and partially calcified nodules according to radiographic findings. Of 111 cases, the average sizes of the solid (84 cases), subsolid (22 cases), and calcified (5 cases) lesions were 1.952 ± 2.225, 1.333 ± 1.827, and 1.152 ± 1.984 cm, respectively. The cytological diagnoses of three groups were compared. A diagnosis of malignancy was made in 64.28% (54 cases) in solid, 22.72% (5 cases) in subsolid, and 20% (1 case) in partially calcified nodules. Among benign lesions, eight granulomatous inflammations were identified, including one case of solid, five cases of subsolid, and two cases of calcified nodules. CONCLUSIONS: Our study indicates that solid nodules have the highest risk of malignancy. Furthermore, the cytological evaluation of subsolid and partially calcified nodules is crucial for the accurate diagnosis and appropriate clinical management of lung nodule patients.

PET and CT features differentiating infectious/inflammatory from malignant mediastinal lymphadenopathy: A correlated study with endobronchial ultrasound-guided transbronchial needle aspiration.

PURPOSE: To explore the advantages of differentiating inflammatory from malignant thoracic lymph nodes by integrating their features on positron emission tomography (PET) and computed tomography (CT). MATERIAL AND METHOD: Following institutional review board approval, PET and CT parameters of thoracic lymph nodes were examined based on their pathologic diagnosis via endobronchial ultrasound-guided transbronchial needle aspiration. The standardized uptake value (SUV) of PET and CT findings of the long- and short-axis diameters, axial short to long diameter ratios (S/L), and measured nodal CT values of the lymph nodes were compared and analyzed statistically. RESULTS: A total of 124 lymph nodes from 70 patients were studied. The inflammatory and malignant lymph nodes differed significantly in their SUV (P = 0.008), short-axis diameters (SAD, p < 0.001), long-axis diameters (LAD, p = 0.002) and S/L ratios (p < 0.001). They did not differ significantly in non-contrast enhanced CT values (p = 0.304). The sensitivities, specificities, positive predictive values, negative predictive values, diagnostic accuracies and diagnostic odds ratios (DOR) were: 1) elevated SUV alone - 95.31% (61/64), 20% (12/60), 55.96% (61/109), 80% (12/15), 58.87% (73/124), and 5; 2) combined SUV + SAD - 89.06%, 53.33%, 67.06%, 82.05%, 71.77%, and 9.31; 3) combined SUV + S/L ratio - 87.5%, 93.33%, 93.33%, 87.5%, 90.32%, and 98, respectively. CONCLUSION: Increased SUV, SAD, LAD, and S/L ratio are accurate PET/CT parameters to characterize inflammatory or malignant lymph nodes. SUV has high sensitivity but low specificity, low positive and negative predictive values, and low DOR. The SUV + SAD and SUV + S/L ratios have higher specificity, positive and negative predictive values, diagnostic accuracy and DOR.

CT findings of primary clear cell carcinoma of liver: with analysis of 19 cases and review of the literature.

PURPOSE: To analyze CT characteristics of primary clear cell carcinoma of the liver (PCCCL) and improve the current understanding and diagnose accuracy of the tumor. METHODS: Pre- and post-contrast CT images of 19 patients with pathology proven PCCCL were retrospectively analyzed. The clinical data and CT findings as well as relevant literature reports were reviewed. RESULTS: Thirteen patients were tested positive for HBsAg, and two patients were positive for HCVAb. The serum alpha-fetoprotein (AFP) levels of most tumors (14/19) were ≤20 ng/ml with 14 cases were associated with liver cirrhosis. All lesions were solitary intraparenchymal mass lesions which have well-defined boarders. On pre-contrast CT scans, 15 lesions appeared as hypo-attenuation and four lesions appeared as isointensity to the adjacent liver parenchyma. On post-contrast CT scans, 16 lesions showed avid enhancement on the hepatic arterial phase, of which 6 lesions were hypo-attenuation, and 10 lesions remained slightly hyper-attenuation or iso-attenuation on the portal venous phase images. Three lesions showed only mild enhancement on the hepatic arterial phase and hypo-attenuation on the portal venous phase. All lesions demonstrated hypointensity on the equilibrium phase. There are 12 lesions showed pseudocapsules. None of patients showed signs of portal vein thrombosis. There was no distal metastasis except only one patient had lymph node metastasis. CONCLUSION: The characteristics of CT imaging of PCCCL, such as tend to form pseudocapsules and less involved with vascular invasion, could be useful in differentiating from common type hepatocellular carcinoma (CHCC). Some CT imaging characteristics of PCCCL are similar to CHCC, such as prone to occur in patients with liver cirrhosis and early enhancement pattern on the hepatic arterial phase as well as hypo-attenuation on the equilibrium phase. Those features could be useful in differentiating PCCCL from other liver tumors, such as hemangioma and hepatic metastases.

Percutaneous computerized tomography guided renal cryoablation using local anesthesia: pain assessment.

PURPOSE: The administration of intravenous sedation during prone computerized tomography guided, percutaneous procedures has the potential for complications. We assessed the pain associated with computerized tomography guided, percutaneous renal cryoablation using straight local anesthesia. MATERIALS AND METHODS: Patients were treated with cryoablation probes inserted into the renal tumor under computerized tomography guidance with local anesthesia. Patients were asked to rate the pain experienced during needle placement and cryoablation using a visual 10-degree pain score scale. Sedation was given when pain was greater than 7 or when requested by the patient. Parameters assessed were cardiopulmonary complications, the need for intravenous supplementation, the pain score during the procedure and the postoperative score. RESULTS: A total of 25 patients (30 tumors) underwent a total of 26 cryoablation sessions with only local anesthesia. Mean patient age +/- SD was 67 +/- 13 years (range 33 to 88). Average tumor and ice ball size was 2.1 +/- 0.7 (range 1.1 to 4.3) and 4.1 +/- 1.0 cm (range 2.6 to 5.9), respectively. The mean dose of 1% lidocaine was 43.89 +/- 24.97 ml (range 10 to 110). All procedures were completed in an average of 68.78 +/- 20.7 minutes (range 40 to 120). Vital signs were not significantly changed during the procedure. Successful completion of percutaneous computerized tomography guided cryoablation using local anesthesia was accomplished in 22 of the 26 sessions (84.62%) without sedation. Four patients required intravenous supplementation. CONCLUSIONS: Percutaneous computerized tomography guided cryoablation for renal tumors can be performed using local anesthesia with minimal discomfort in most patients.