Language：English   Publishing type：Research paper (scientific journal)  

PURPOSE: To evaluate the feasibility of percutaneous needle biopsy using a 1.2 Tesla open magnetic resonance imaging (MRI) system, which has the highest field strength among the currently available open MRI systems. MATERIALS AND METHODS: This single-center prospective study included 10 patients. The primary endpoint was the feasibility of biopsy needle insertion into a target lesion under 1.2 Tesla open MRI guidance. The secondary endpoints included adverse events, device failures, and success of tissue specimen acquisition. Biopsy was performed for targets in various organs using an MRI-compatible coaxial needle system consisting of a 16G introducer needle and 18G semi-automatic biopsy needle. A newly developed body coil with a suitable design for intervention was used for intraprocedural imaging. RESULTS: Biopsy procedures were performed for six musculoskeletal masses, two retroperitoneal masses, one renal mass, and one liver mass. The median diameter of the targets was 4.9 cm (range 2.1-22.8 cm). MRI-guided biopsy needle insertion was feasible in all 10 patients. In total, four grade 1 adverse events (as per Common Terminology Criteria for Adverse Events version 4.0) occurred in three patients. Adequate biopsy specimens for pathological diagnosis were successfully obtained from all 10 patients. CONCLUSION: Percutaneous needle biopsy using a 1.2 Tesla open MRI system was feasible for relatively large targets, especially in the musculoskeletal region.

DOI： 10.1007/s11604-021-01211-8

PubMed

researchmap

Authorship：Lead author   Language：English  

DOI： 10.1007/s00270-021-02995-y

PubMed

researchmap

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

PURPOSE: To evaluate the characteristics of needle artifacts and the accuracy of needle insertion using a 1.2 Tesla open magnetic resonance imaging (MRI) system in a phantom. MATERIALS AND METHODS: First, the apparent width of the needle on the MRI and the needle tip position error of 16- and 18-gauge MRI-compatible introducer needles and a 17-gauge cryoneedle were examined with different needle angles (0°, 30°, 45°, 60°, and 90°) to the main magnetic field (B0), sequence types (balanced steady-state acquisition with rewound gradient echo [BASG] and T2-weighted fast spin echo [FSE] sequence), and frequency encoding directions. Second, the accuracy of needle insertion was evaluated after 10 MRI fluoroscopy-guided insertions in a phantom. RESULTS: The apparent needle widths was larger when the angle of the needle axis relative to B0 was larger. The needles appeared larger on BASG than on T2-weighted FSE images, with the largest apparent widths of 16-, 17-, and 18-gauge needles of 14.3, 11.6, and 11.0mm, respectively. The apparent needle tip position was always more distal than the actual position on BASG images, with the largest longitudinal error of 4.0mm. Meanwhile, the 16- and 18-gauge needle tips appeared more proximal on T2-weighted FSE images with right-to-left frequency encoding direction. The mean accuracy of MRI fluoroscopy-guided needle insertion was 3.1mm. CONCLUSION: These experiments clarify the characteristics of needle artifacts in a 1.2 Tesla open MRI. With this system, the MRI fluoroscopy-guided needle insertion demonstrated an acceptable accuracy for clinical use.

DOI： 10.1016/j.diii.2020.12.007

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

OBJECTIVES: To identify the diagnostic performance of magnetic resonance imaging (MRI) in the knee-flexed position for the detection of meniscal ramp lesions in patients with anterior cruciate ligament tears. MATERIALS AND METHODS: Forty-three patients (mean age 24.5 ± 9.5 years; 21 males, 22 females) with an arthroscopically proven anterior cruciate ligament tear were included in this retrospective study. The presence of the following two important features on MRI was recorded: irregularity of the medial meniscus at the posterior margin, and complete fluid filling between the posterior horn of the medial meniscus and the capsule margin. Findings obtained in arthroscopy served as the reference standard. The diagnostic sensitivity, specificity, and inter-observer agreement were calculated. RESULTS: Sixteen ramp lesions were noted on arthroscopy (37.2%). With an irregularity of the medial meniscus at the posterior margin on MRI, the sensitivity and specificity were 87.5 and 59.3% at 10° knee flexion and 93.8 and 85.2% at 90° flexion, respectively. The complete fluid filling sign on MRI showed sensitivity and specificity of 31.3 and 100% at 10° knee flexion and 87.5 and 100% at 90° flexion, respectively. The concordance between the two observers for the two MRI features was very good (k = 0.70-0.88). CONCLUSION: MRI with the knee in the flexed position improves the diagnostic performance of the detection of meniscal ramp lesions compared with MRI with the knee in the extended position.

DOI： 10.1007/s00256-020-03480-2

PubMed

researchmap

Authorship：Lead author   Language：English  

We describe three cases of renal cell carcinoma (RCC) with recurring local tumor progression, i.e., local failure following repeat cryoablation for a locally progressed tumor. A second local progression developed in all cases after cryoablation for the first local progression, despite there being a sufficiently large ice-ball margin. In two cases, the second local progression was treated with microwave ablation and controlled in the follow-up. In one case, a third cryoablation was performed, but a third local progression developed after 12 months. These cases suggest that some RCCs may be refractory to cryoablation. In cases of recurring local progression, switching from cryoablation to another ablation modality may be an alternative.

DOI： 10.22575/interventionalradiology.2019-0014

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

PURPOSE: To assess specimen weight difference of six types of semi-automatic cutting biopsy needles. MATERIALS AND METHODS: We compared 18- and 20-gauge needles, one aspiration-type (STARCUT® aspiration-type, TSK Laboratory, Tochigi, Japan) and five non-aspiration-type (MISSION®, BARD, AZ; SuperCore™, Argon Medical Devices, TX; Temno Evolution®, Care Fusion, IL; FINE CORE®, Toray Medical, Tokyo, Japan; Quick-Core®, Cook, IN) needles. Four biopsies were performed with each needle with the longest throw length on an excised bovine liver. The biopsies were repeated with new needles, four times with four different livers. STARCUT® was used both with and without aspiration. RESULTS: Sixteen specimens were obtained with each needle. In needles of gauges, STARCUT® with aspiration provided the heaviest specimen and significantly heavier specimens were obtained with STARCUT® with aspiration (P < 0.05) than five non-aspiration-type needles. The specimen weight differed significantly (P < 0.001) among all 18- and 20-gauge needles. The specimen weights did not differ significantly between aspiration and non-aspiration biopsies with STARCUT® (6.32 vs. 5.97 mg with 18-gauge needle, P = 0.342; 1.95 vs. 1.92 mg with 20-gauge needle, P = 0.886). CONCLUSION: Although STARCUT® with aspiration provided the heaviest specimen, specimen weights were not significantly different between aspiration and non-aspiration biopsies. We assessed the specimen weight difference of six types of semi-automatic cutting biopsy needles. Significantly heavier specimens were obtained with STARCUT® with aspiration than the other needles. The specimen weight differed significantly among all 18- and 20-gauge needles but did not differ significantly between aspiration and non-aspiration biopsies with STARCUT®.

DOI： 10.1007/s11604-020-00935-3

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

OBJECTIVES: To evaluate the accuracy of robotic CT-guided out-of-plane needle insertion in phantom and animal experiments. METHODS: A robotic system (Zerobot), developed at our institution, was used for needle insertion. In the phantom experiment, 12 robotic needle insertions into a phantom at various angles in the XY and YZ planes were performed, and the same insertions were manually performed freehand, as well as guided by a smartphone application (SmartPuncture). Angle errors were compared between the robotic and smartphone-guided manual insertions using Student's t test. In the animal experiment, 6 robotic out-of-plane needle insertions toward targets of 1.0 mm in diameter placed in the kidneys and hip muscles of swine were performed, each with and without adjustment of needle orientation based on reconstructed CT images during insertion. Distance accuracy was calculated as the distance between the needle tip and the target center. RESULTS: In the phantom experiment, the mean angle errors of the robotic, freehand manual, and smartphone-guided manual insertions were 0.4°, 7.0°, and 3.7° in the XY plane and 0.6°, 6.3°, and 0.6° in the YZ plane, respectively. Robotic insertions in the XY plane were significantly (p < 0.001) more accurate than smartphone-guided insertions. In the animal experiment, the overall mean distance accuracy of robotic insertions with and without adjustment of needle orientation was 2.5 mm and 5.0 mm, respectively. CONCLUSION: Robotic CT-guided out-of-plane needle insertions were more accurate than smartphone-guided manual insertions in the phantom and were also accurate in the in vivo procedure, particularly with adjustment during insertion. KEY POINTS: • Out-of-plane needle insertions performed using our robot were more accurate than smartphone-guided manual insertions in the phantom experiment and were also accurate in the in vivo procedure. • In the phantom experiment, the mean angle errors of the robotic and smartphone-guided manual out-of-plane needle insertions were 0.4° and 3.7° in the XY plane (p < 0.001) and 0.6° and 0.6° in the YZ plane (p = 0.65), respectively. • In the animal experiment, the overall mean distance accuracies of the robotic out-of-plane needle insertions with and without adjustments of needle orientation during insertion were 2.5 mm and 5.0 mm, respectively.

DOI： 10.1007/s00330-019-06477-1

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NAGOYA UNIV, SCH MED  

There has been growing interest in magnetic resonance imaging (MRI)-guided interventional procedures such as percutaneous needle biopsy. Although open MRI is preferable for MRI-guided procedures in terms of patient accessibility, its inferior imaging capability due to lower field strength is a substantial limitation. In this situation, the high-field (1.2T) open MRI has recently become available. This novel MRI system is expected to provide excellent image quality as well as good patient accessibility, potentially contributing to safe and accurate device manipulation. This trial is designed to investigate the feasibility of MRI-guided percutaneous needle biopsy with this system. Patients with lesions needing percutaneous needle biopsy for pathological diagnosis are included. The enrollment of ten patients is intended. The primary endpoint of this study is the feasibility of biopsy needle insertion under real-time MR-fluoroscopy guidance based on the presence of the notch of the biopsy needle within the target lesion. The secondary endpoints are adverse events, device failures, and success of specimen acquisition. Once the feasibility of MRI-guided biopsy with 1.2T open MRI is validated by this study, it may potentially encourage widespread use of MRI-guidance for biopsy procedures. Furthermore, it may lead to development of the other MRI-guided interventional procedures using this MRI system.

DOI： 10.18999/nagjms.81.3.463

Web of Science

Scopus

PubMed

researchmap

Language：English  

Intrapulmonary solitary fibrous tumors (SFTs) are extremely rare neoplasms. We report a case of an intrapulmonary SFT and describe the findings of computed tomography (CT) and F-18 fluorodeoxyglucose positron emission tomography. The case indicates that a benign intrapulmonary SFT can present as a ground-glass nodule in the early stages of disease and may appear as a well-defined, lobular, homogeneously enhanced mass with slow growth on chest CT images. To our knowledge, this is the first report describing the natural course of an intrapulmonary SFT over 16 years based on the findings of chest CT and F-18 fluorodeoxyglucose positron emission tomography/CT.

DOI： 10.1016/j.radcr.2019.03.023

PubMed

researchmap