The usefulness of vertebral needle targeting simulation training system using ray-summation imaging: experimental study.

PURPOSE: Using the multi-detector computed tomography and related three-dimensional imaging technology, we developed a vertebral needle targeting simulation training system named spinal needling intervention practice using ray-summation imaging (SNIPURS). Herein, we assessed the utility of SNIPURS by evaluating changes in the learning curves of SNIPURS trainees. METHODS: Twenty-one examinees were enrolled: seven experienced operators (expert group), seven trainees with coaching (coaching group), and seven trainees without coaching (non-coaching group). They performed six tests of vertebral needle targeting simulation on the workstation-generated spinal ray-summation images of six patients with vertebral fractures. In each test, they determined the bilateral trans-pedicular puncture points and angles on two thoracic and two lumbar vertebrae on ray-summation imaging (i.e., 8 simulations per test). The coaching group received coaching by a trainer after Tests 1 and 4, while the others did not. Scores were given based on the trans-pedicular pathway (1 point) or not (0 point). Eight virtual needles were evaluated in each of Tests 1-6. RESULTS: Among the three groups, the expert group had the highest average scores on Tests 1-4 (expert: 3.86, 6.57, 7.43, and 7.57; coaching: 1.86, 6.14, 6, and 6.29; and non-coaching: 1.14, 4.14, 4.71, and 4.86). The coaching group's scores caught up with the expert groups' average scores on Tests 5 and 6, whereas those of the non-coaching group did not (expert and coaching: 7.86 and 8.00, non-coaching: 5.86 and 7.14). All examinees in the expert and coaching groups achieved a perfect score on the final Test 6, whereas three of the seven non-coaching trainees did not. CONCLUSION: SNIPURS might be suitable for vertebral needle targeting training. The coaching provided during SNIPURS training helped the trainees to acquire the spinal puncture techniques in PVP.

Change in cancer diagnosis during the COVID-19 pandemic: Trends estimated from FDG-PET/CT.

The aim of this study is to clarify changes in the circumstances of cancer diagnoses during the COVID-19 pandemic in Tokyo, Japan, estimated from [18F]-2-fluoro-2-deoxy-D-glucose (FDG) -positron emission tomography/ computed tomography (PET/CT) for cancer patients. Cancer diagnosis in pandemic status (PANS) was evaluated by retrospective review of the findings of FDG-PET/CT examinations performed between 11 March 2020 and 28 December 2021 for initial staging and restaging for malignancy. Evaluation of cancer diagnosis in pre-pandemic status (pPANS) was conducted similarly in FDG-PET/CT examinations performed between 4 January 2018 and 10 March 2020. Of these, patients with malignant lymphoma (ML), lung cancer, esophageal cancer, and colorectal cancer who had a pathologically proven diagnosis or clinical diagnosis following therapy of the disease were selected for analysis. Initial cancer staging was determined by the diagnostic report of FDG-PET/CT. Change in cancer stage and in the number of FDG-PET/CT examinations performed was evaluated between pPANS and PANS, and according to term of the pandemic and vaccination status. The COVID-19 epidemic influenced the number of cancer patients who underwent FDG-PET/CT. There was a marked decrease in the number of cancer patients receiving FDG-PET/CT in Terms 1-3 (March 2020 to February 2021), but it recovered in Terms 4-6 (March 2021 to December 2021). There was no significant difference between PANS and pPANS in terms of the initial stage of cancer, but Stage IV ML and Stage II esophageal cancer were more frequent in PANS. Initial staging of ML, lung cancer, and esophageal cancer revealed more advanced cancer stages in Terms 4-6 compared with Terms 1-3. The number of patients receiving FDG-PET/CT in Tokyo was influenced by the COVID-19 epidemic. Staging based on FDG-PET/CT shifted to more advanced cancer stage during the pandemic compared with pre-pandemic.

Accuracy of vertebral puncture in percutaneous vertebroplasty.

PURPOSE: To clarify the accuracy of vertebral puncture of the vertebral tertile area needling (VETERAN) method puncturing the pedicle superimposed on one-third of the width between the lateral vertebral line to the contralateral medial lamina line compared with Cathelin-needle-assisted puncture (CAP) method puncturing using the Cathelin needle as a guide in percutaneous vertebroplasty. MATERIALS AND METHODS: 449 punctures by CAP method and 125 punctures by VETERAN method were enrolled. We compared the puncture accuracy of both methods. We estimated a vertebral estimated tilting ratio (VET-ratio) defined as ratio of the distance between the lateral vertebral line and the contralateral medial laminal line to the distance between the vertebral lateral line and the puncture point measured by computed tomography. We also estimated the procedural items and clinical outcomes. RESULTS: VETERAN method with 100% of punctures within safe zone (cortical breaches within 2 mm) had significantly higher accuracy than CAP method with 97.8% (p < 0.01) for the 2 mm incremental evaluation. No cases with a VET-ratio of 36% or less had cortical breaches. VETERAN method had shorter operative time per puncture (p < 0.01) and exposure time per puncture (p < 0.05). CONCLUSION: VETERAN method reduced the occurrence of the inaccurate puncture, operative times, and exposure times. A VET-ratio with 36% or less is associated with a safe puncture using VETERAN method.

Fatty liver on computed tomography scan on admission is a risk factor for severe coronavirus disease.

OBJECTIVES: To alleviate the overflow of coronavirus disease 2019 (COVID-19) patients in hospitals, less invasive and simple criteria are required to triage the patients. We evaluated the relationship between COVID-19 severity and fatty liver on plain computed tomography (CT) scan performed on admission. METHODS: In this retrospective cohort study, we considered all COVID-19 patients at a large tertiary care hospital between January 31 and August 31, 2020. COVID-19 severity was categorized into severe (moderate and severe) and non-severe (asymptomatic and mild) groups, based on the Japanese National COVID-19 guidelines. Fatty liver was detected on plain CT scan. Multivariate logistic regression analysis was performed to evaluate factors associated with severe COVID-19. RESULTS: Of 222 patients (median age: 52 years), 3.2%, 58.1%, 20.7%, and 18.0% presented with asymptomatic, mild, moderate, and severe COVID-19, respectively. Although 59.9% had no fatty liver on plain CT, mild, moderate, and severe fatty liver occurred in 13.1%, 18.9%, and 8.1%, respectively. Age and presence of fatty liver were significantly associated with severe COVID-19. CONCLUSION: Our study showed that fatty liver on plain CT scan on admission can become a risk factor for severe COVID-19. This finding may help clinicians to easily triage COVID-19 patients.

A fundamental study assessing the generalized fitting method in conjunction with every possible coalition of N-combinations (G-EPOC) using the appendicitis detection task of computed tomography.

PURPOSE: Increased use of deep learning (DL) in medical imaging diagnoses has led to more frequent use of 10-fold cross-validation (10-CV) for the evaluation of the performance of DL. To eliminate some of the (10-fold) repetitive processing in 10-CV, we proposed a "generalized fitting method in conjunction with every possible coalition of N-combinations (G-EPOC)", to estimate the range of the mean accuracy of 10-CV using less than 10 results of 10-CV. MATERIAL AND METHODS: G-EPOC was executed as follows. We first provided (2N-1) coalition subsets using a specified N, which was 9 or less, out of 10 result datasets of 10-CV. We then obtained the estimation range of the accuracy by applying those subsets to the distribution fitting twice using a combination of normal, binominal, or Poisson distributions. Using datasets of 10-CVs acquired from the practical detection task of the appendicitis on CT by DL, we scored the estimation success rates if the range provided by G-EPOC included the true accuracy. RESULTS: G-EPOC successfully estimated the range of the mean accuracy by 10-CV at over 95% rates for datasets with N assigned as 2 to 9. CONCLUSIONS: G-EPOC will help lessen the consumption of time and computer resources in the development of computerbased diagnoses in medical imaging and could become an option for the selection of a reasonable K value in K-CV.

Safety and Efficacy of Percutaneous Vertebroplasty for Osteoporotic Vertebral Compression Fractures: A Multicenter Retrospective Study in Japan.

Purpose: Bone cement enhancement by percutaneous vertebroplasty (PVP) for the treatment of osteoporotic vertebral compression fractures remains unapproved, as it has not been fully evaluated in Japan. The current multicenter study was conducted in Japan to verify the safety and efficacy of PVP in patients with painful osteoporotic vertebral fractures. Material and Methods: In this retrospective study, we referred to previous studies to evaluate the non-inferiority of PVP to balloon kyphoplasty (BKP). We reviewed consecutive patient data from April 2017 to March 2018 from four institutions based on the medical records of the intervention. We statistically investigated the adverse events due to cement leakage or other factors associated with PVP, and new vertebral compression fractures after PVP were evaluated for safety, pain relief, and gait improvement. Results: This study included 485 patients; most of whom were in the middle- to oldest- age groups (mean age, 81.4 years). No serious adverse events were reported in patients available for safety evaluation (n = 485). Cement leakage and new vertebral compression fractures occurred in 35.7% and 18.6% (26.2%-38.4% and 8.9%-20.7%) of the patients undergoing PVP, respectively, both of which were also judged to be equivalent to those of BKP. The pain score improved in those undergoing PVP, and this improvement was maintained during a one-year follow-up. Of the 206 patients who had difficulty walking at baseline, 156 had restored walking at discharge. Conclusions: PVP was shown to be a safe and effective treatment, even in elderly patients with painful osteoporotic vertebral fractures.

Diagnosis of celiac artery stenosis using multidetector computed tomography and evaluation of the collateral arteries within the mesopancreas of patients undergoing pancreaticoduodenectomy.

INTRODUCTION: Celiac artery (CA) stenosis (CAS), caused by various factors, is often asymptomatic because collateral blood flow from the superior mesenteric artery supplies the CA outflow region. The purpose of this study was to investigate the usefulness of multidetector computed tomography (MDCT) for diagnosing CAS and associated collateral artery formation, and elucidating the effect of CAS on the numbers and diameters of the arteries within the mesopancreas. MATERIALS AND METHODS: We investigated 106 patients who underwent contrast-enhanced MDCT, before pancreaticoduodenectomy, between January 2015 and September 2019. MDCT was used to determine the percentage stenosis of the CAs; patients were classified into CAS (-) (0-29% stenosis) and CAS (+) (30-100% stenosis) groups. The dissection lines of the mesopancreas were classed as Level I or II, and the numbers and diameters of the arteries along each dissection line were counted and measured. RESULTS: There were 27 CAS (+) patients and 79 CAS (-) patients. In the CAS (+) group there were more arteries and they had larger diameters than those in the CAS (-) group, at both Levels I and II. There were significantly more arteries when the CA stenosis was ≥30% and they had larger diameters when the stenosis was ≥50%. CONCLUSIONS: MDCT is useful for diagnosing CAS, and CAS is associated with larger numbers and diameters of the arteries within the mesopancreas.

A Fundamental Study Assessing the Diagnostic Performance of Deep Learning for a Brain Metastasis Detection Task.

PURPOSE: Increased use of deep convolutional neural networks (DCNNs) in medical imaging diagnosis requires determinate evaluation of diagnostic performance. We performed the fundamental investigation of diagnostic performance of DCNNs using the detection task of brain metastasis. METHODS: We retrospectively investigated AlexNet and GoogLeNet using 3117 positive and 37961 negative MRI images with and without metastasis regarding (1) diagnostic biases, (2) the optimal K number of K-fold cross validations (K-CVs), (3) the optimal positive versus negative image ratio, (4) the accuracy improvement curves, (5) the accuracy range prediction by the bootstrap method, and (6) metastatic lesion detection by regions with CNNs (R-CNNs). RESULTS: Respectively, AlexNet and GoogLeNet had (1) 50 ± 4.6% and 50 ± 4.9% of the maximal mean ± 95% confidence intervals (95% CIs) measured with equal-sized negative versus negative image datasets and positive versus positive image datasets, (2) no less than 10 and 4 of K number in K-CVs fell within the respective maximum biases of 4.6% or 4.9%, (3) 74% of the highest accuracy with equal positive versus negative image ratio dataset and 91% of that with four times of negative-to-positive image ratio dataset, (4) the accuracy improvement curves increasing from 69% to 74% and 73% to 88% as positive versus negative pairs of the training images increased from 500 to 2495, (5) at least nine and six out of 10-CV result sets essential to predict the accuracy ranges by the bootstrap method, and (6) 50% and 45% of metastatic lesion detection accuracies by R-CNNs. CONCLUSIONS: Our research presented methodological fundamentals to evaluate diagnostic features in the visual recognition of DCNNs. Our series will help to conduct the accuracy investigation of computer diagnosis in medical imaging.

A case of Klebsiella pneumoniae spondylitis and bacteremia potentially due to inflammation around a fecalith.

We herein report a case of Klebsiella pneumoniae (K. pneumoniae) spondylitis and bacteremia in a 90-year-old man with diabetes mellitus who had undergone sigmoidectomy and had a fecalith. Two months prior to admission, he had received antimicrobial treatment for 2 weeks for K. pneumoniae bacteremia whose entry was unclear and he was readmitted to our hospital owing to fever and stomachache. K. pneumoniae was isolated from two sets of blood cultures, and computed tomography and magnetic resonance imaging revealed inflammation and destruction of the 8th and 9th thoracic vertebra. The diagnosis was spondylodiscitis secondary to K. pneumoniae bacteremia. Although the entry point for K. pneumoniae was unclear, we suggest that inflammation of the mucosa around the fecalith might have caused the Enterobacteriaceae bacteremia.

The safety and efficacy of percutaneous vertebroplasty for patients over 90 years old.

OBJECTIVE: To retrospectively analyze the safety and efficacy of percutaneous vertebroplasty (PVP) for patients aged 90 or over. MATERIALS AND METHODS: We analyzed 130 consecutive patients with osteoporotic vertebral fractures who underwent a first-time PVP between May 2015 and September 2017 at our institution. We divided them into the elder patient group aged 90 years or over (n = 21) and the younger patient group under 90 years (n = 109). We compared the two groups' background, treatments, and outcomes using univariate analyzes and the log rank test. RESULTS: A significant difference was observed in dementia (19% in the younger group vs. 48% in the elder group, p < 0.01). No significant difference was revealed in the procedure time or the rate of complications. The post-PVP mobility function and the pain level were significantly improved compared to before PVP in both groups (p < 0.01 each). No significant differences were observed between the two groups in the recurrence of vertebral fracture after treatment (17% vs. 14%) or the 1-year survival rate (79% vs. 86%), respectively. CONCLUSION: The results of our analyzes suggested that a PVP can safely and effectively contribute to pain relief as well as the restoration of ambulation for patients aged 90 or over.

Artificial intelligence using neural network architecture for radiology (AINNAR): classification of MR imaging sequences.

PURPOSE: The confusion of MRI sequence names could be solved if MR images were automatically identified after image data acquisition. We revealed the ability of deep learning to classify head MRI sequences. MATERIALS AND METHODS: Seventy-eight patients with mild cognitive impairment (MCI) having apparently normal head MR images and 78 intracranial hemorrhage (ICH) patients with morphologically deformed head MR images were enrolled. Six imaging protocols were selected to be performed: T2-weighted imaging, fluid attenuated inversion recovery imaging, T2-star-weighted imaging, diffusion-weighted imaging, apparent diffusion coefficient mapping, and source images of time-of-flight magnetic resonance angiography. The proximal first image slices and middle image slices having ambiguous and distinctive contrast patterns, respectively, were classified by two deep learning imaging classifiers, AlexNet and GoogLeNet. RESULTS: AlexNet had accuracies of 73.3%, 73.6%, 73.1%, and 60.7% in the middle slices of MCI group, middle slices of ICH group, first slices of MCI group, and first slices of ICH group, while GoogLeNet had accuracies of 100%, 98.1%, 93.1%, and 94.8%, respectively. AlexNet significantly had lower classification ability than GoogLeNet for all datasets. CONCLUSIONS: GoogLeNet could judge the types of head MRI sequences with a small amount of training data, irrespective of morphological or contrast conditions.

Regression of thymoma associated with a multilocular thymic cyst: report of a case.

A 28-year-old male was diagnosed with acute pericarditis after presenting with acute chest pain, fever and an abnormality in an electrocardiogram. No symptoms suggestive of myasthenia gravis were observed. Although the symptoms were alleviated by antibiotics, computed tomography (CT) showed an anterior mediastinal mass with bilateral pleural effusion. He was, therefore, diagnosed with thymoma and referred to our hospital. Surgery was performed, since the pleural effusion disappeared. The pathological examination revealed the mass to be a type B2 thymoma classified as pathological stage I (Masaoka's classification) with a multilocular thymic cyst.

Angiomyolipomas of the mediastinum and the lung.

Angiomyolipomas are benign neoplasms composed of various tissues, including components of fat, abnormal blood vessels, and smooth muscle cells. They most commonly occur in the kidney, but on rare occasions they occur in extrarenal sites. We present a case of angiomyolipomas in the mediastinum and lung, possibly associated with lymphangioleiomyomatosis and tuberous sclerosis complex.

Signet ring cell adenocarcinoma of the lung with an EML4-ALK fusion gene mimicking mucinous (colloid) adenocarcinoma: a case report.

We herein report a case of signet ring cell adenocarcinoma of the lung with an EML4-ALK fusion gene mimicking mucinous (colloid) adenocarcinoma. A 79-year-old female presented with a pulmonary tumor located in the right lower lobe measuring 21 mm in size. A right lower lobectomy was performed. The postoperative pathological examination revealed signet ring cell carcinoma with abundant mucin pools, and a multiplex RT-PCR analysis revealed the variant 2 inversion of the EML4-ALK gene.

Usefulness of F-18 FDG PET/CT in a case of Kaposi sarcoma with an unexpected bone lesion.

Bone lesions of Kaposi sarcoma are rare. A 56-year-old man who was HIV positive and was diagnosed with Kaposi sarcoma on the basis of the results of a biopsy of skin lesions, underwent F-18 FDG PET/CT scan for detecting Kaposi sarcoma lesions and other AIDS-related diseases. An abnormal uptake was observed in the lumbar spine. MRI showed a diffuse enhanced spine lesion, and Ga-67 and ²°¹Tl scanning were negative. As a result, the lesion was considered to be a Kaposi sarcoma, and the shrinkage of the lesion was noted after the therapy for Kaposi sarcoma.

Whole-body 18F-fluorodeoxyglucose positron emission tomography/computed tomography images before and after chemotherapy for Kaposi sarcoma and highly active antiretrovirus therapy.

Kaposi sarcoma is an acquired immunodeficiency syndrome-related disease that mainly involves the skin, gastrointestinal gut, and lungs. Whole-body 18F-fluorodeoxyglucose-positron emission tomography and computed tomography (FDG-PET/CT) scanning is useful for simultaneous detection of multiple lesions of Kaposi sarcoma. We present a 67-year-old man with a history of infection with human immunodeficiency virus who presented with numerous cutaneous lesions. FDG-PET/CT images showed lesions in the skin, lung, and lymph nodes. The gastrointestinal lesions were detected using gastric fiberscopy (GF) and colon fiberscopy (CF). After Kaposi sarcoma therapy, the uptake in the lesions of the skin, lung, and lymph nodes decreased, but new lesions were detected in the pancreas and lumbar spine. He had pancreatitis and Candida spondilitis. Whole-body FDG-PET/CT is useful for detecting lesions and determining the extension to which the disease has spread, adding the gastrointestinal lesions by GF and CF. After therapy, FDG-PET/CT can be used to demonstrate which lesions remain active and to determine the overall response to treatment. In this case, we show how useful FDG-PET/CT is and how difficult it is to treat Kaposi sarcoma.

The management of pyothorax-associated lymphoma using 18F-FDG PET/CT.

OBJECTIVE: Pyothorax-associated lymphoma (PAL) is a rare form of lymphoma and its management on (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) combined computed tomography (CT) has not been well reported. The purpose of this study was to evaluate the usefulness of FDG PET/CT in patients with PAL. MATERIALS AND METHODS: Twenty-four PET/CT images in seven patients (5 men and 2 women) with PAL were studied retrospectively. Five of the 24 PET/CT scans were done for diagnosis and staging, 6 for restaging, 3 for follow-up, and 10 to evaluate the treatment response. PET/CT scan interpretations were performed visually and using the maximum standardized uptake values (SUVmax). Additionally, the efficacy of the enhanced CT findings in pre- and post-treatments was described. RESULTS: Six of the 7 patients with PAL received radiotherapy, and the efficacy of treatment was observed in their lesions. The percentage decrease of SUVmax in PAL was useful in providing complementary information. Enhanced CT findings showed decreasing enhancement of PAL after treatment; however, in five cases, residual masses were confirmed after treatment. CONCLUSION: FDG PET/CT may be an ideal modality for reducing the false-positive interpretation of residual masses occurring after treatment for PAL. The SUVmax provides complementary information for the management of PAL.

Diagnostic usefulness of 18F-FDG PET/CT in the differentiation of pulmonary artery sarcoma and pulmonary embolism.

OBJECTIVE: The purpose of this study was to evaluate the usefulness of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in differentiating pulmonary artery sarcoma from pulmonary embolism. MATERIALS AND METHODS: We evaluated three patients with pulmonary artery sarcoma and 10 patients with proximal pulmonary embolism (6 men and 7 women, ranging in age from 35 to 94 years). All the patients had evidence of perfusion defects in their proximal pulmonary arteries on contrast-enhanced computed tomography (CT) scans performed prior to PET/CT. The maximum standardized uptake value (SUV(max)) of FDG uptake in all the lesions was measured using PET/CT. The location of lesions, background uptake or thrombi in the legs were evaluated in both groups as basic characteristics. RESULTS: The mean SUV(max) of the pulmonary artery sarcomas (7.63 +/- 2.21, n = 3) and the pulmonary embolisms (2.31 +/- 0.41, n = 10) were significantly different (P < 0.05). The mean times between the initial contrast-enhanced CT scan and PET/CT scan were similar in both groups (P = 0.7804). The differences in the locations in lesions between the three groups (right, left and bilateral) or background uptakes were not significant. CONCLUSION: FDG PET/CT could distinguish pulmonary artery sarcoma from pulmonary embolism based on the SUV(max) value.

Percutaneous osteoplasty for hypervascular bone metastasis.

We report three cases of percutaneous osteoplasty for the treatment of hypervascular bone metastasis. Four hypervascular bone metastases were treated in three consecutive patients by percutaneous osteoplasty under fluoroscopic or computed tomographic guidance. Primary malignant tumors included pheochromocytoma and renal cell carcinoma. Pain relief after osteoplasty was achieved in all three patients. There was no major complication. Projectile bleeding and subcutaneous hematoma were noted during or after osteoplasty but were easily controlled conservatively. Percutaneous osteoplasty for hypervascular bone metastases is not only a highly effective but also a minimally invasive technique that provides immediate pain relief without major complication.