Miliary tuberculosis diagnosed by diffuse hepatic uptake on PET/CT and transjugular liver biopsy.

The patient was an 81-year-old man. In his 20s, he had been treated with pharmacotherapy for pulmonary tuberculosis for 1 year. He presented to the Department of Respiratory Medicine with a chief complaint of dyspnea. The possibility of respiratory disease appeared to be low, but hepatic impairment was detected. The patient was thus referred to our department. Though the cause of hepatic impairment was unknown, the soluble interleukin-2 receptor level was elevated, suggesting malignant lymphoma. 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)-computed tomography (CT) revealed diffuse, homogenous, intense FDG uptake in the entire liver, and transjugular liver biopsy confirmed the diagnosis. Histopathological examination revealed an epithelioid granuloma, and auramine staining was positive for bacilli suggestive of tuberculosis. CT revealed diffuse micronodular shadows in the lung, yielding a diagnosis of miliary tuberculosis. Therefore, the patient was prescribed antituberculosis medication by the Department of Respiratory Medicine. His subsequent clinical course was good. The miliary (hepatic) tuberculosis was typical based on the diffuse, homogenous, intense FDG uptake throughout the liver observed on PET-CT.

Oral pharmacokinetics of sulfadiazine and sulfamonomethoxine in female Holstein milking cows.

The efficacy of orally administered drugs in cattle is thought to be slow because of the anatomical and physiological features of their forestomach. Thus, parenteral routes are mainly preferred to administer drugs. However, the effect of some drugs with unique physicochemical properties was promptly obtained even after oral administration in clinically ill cattle. Therefore, the present study aimed to investigate pharmacokinetically the usefulness of the oral route in cattle by comparing the oral pharmacokinetic properties of two sulfonamides with different physicochemical properties. Sulfadiazine (SDZ) and sulfamonomethoxine (SMM) were administered by intravenous and oral route to four female Holstein cows with a 4-weeks washout period. Blood samples were collected over time, and SDZ and SMM concentrations in plasma were analyzed by HPLC. Data obtained from the same animal after intravenous and oral administration were simultaneously analyzed with the one compartment model, and kinetic parameters were calculated. The Tmax (mean ± SD) of SMM (2.75 ± 0.96 hr) was significantly achieved earlier than that of SDZ (5.00 ± 1.15 hr). Further, the mean absorption time of SMM (5.24 ± 0.69 hr) was significantly shorter than that of SDZ (5.92 ± 1.11 hr). Also, the half-life of absorption of SMM (3.91 ± 0.51 hr) was significantly shorter than that of SDZ (4.51 ± 0.82 hr). These data suggest that the absorption rates of highly unionized drugs (such as SMM) from the forestomach of cattle may be markedly higher than less unionized ones (such as SDZ).

Graft failure after allogeneic islet transplantation in a patient with type 1 diabetes and a high anti-glutamic acid decarboxylase antibody titer.

Pancreatic islet transplantation is a ß-cell replacement therapy for people with insulin-deficient diabetes who have difficulty in glycemic control and suffer from frequent severe hypoglycemia. However, the number of islet transplantations carried out is still limited in Asia. We report a case of allogeneic islet transplantation in a 45-year-old Japanese man with type 1 diabetes. Although the islet transplantation was successfully carried out, graft loss was observed on the 18th day. Immunosuppressants were used in accordance with the protocol, and donor-specific anti-human leukocyte antigen antibodies were not detected. Autoimmunity relapse was also not observed. However, the patient had a high titer of anti-glutamic acid decarboxylase antibody from before the islet transplantation, and autoimmunity might thus have affected the ß-cells in the transplanted islet. The evidence is still scarce to reach conclusions, and further data accumulation is required to enable proper patient selection before islet transplantation.

Prediction of the Spontaneous Estrus Expression Period Based on Large (≥10 mm) Follicle Numbers in Lactating Holstein Dairy Cows.

The objectives of this study were (1) to investigate the distribution of large (≥10 mm) follicle numbers during the estrous cycle and (2) to compare the timing of the estrus expression period after the ovarian examination between cows with one large follicle (1F) and two or more large follicles (2F) with functional corpus luteum (CL) at the ovarian examination in lactating Holstein dairy cows. In experiment 1, we performed 393 ovarian examinations by ultrasonography, addressed the existence of CL (≥20 mm) and large follicle numbers, and classified cows into 1F (n = 229) and 2F (n = 164) groups. The 1F appearance rates were beyond 75% each day during 3 to 12 d after estrus. However, 2F appearance rates were beyond 75% each day during 15 to 24 d after estrus. In experiment 2, we performed 302 ovarian examinations by ultrasonography and classified cows into the 1F (n = 168) and 2F (n = 134) groups. Estrus detection was performed for 24 d after the ovarian examination in each cow. In the 2F group, 75% of estrus occurred within 9 d of the ovarian examination. However, 75% of estrus occurred 10 d after the ovarian examination in 1F. Days from the ovarian examination to estrus were significantly shorter in the 2F (6.0 d; median, 7.2 ± 4.0 d; mean ± SD) than in the 1F (13 d, 12.4 ± 4.3 d) group. In conclusion, focusing on ≥10 mm follicle numbers with CL could be useful for predicting the estrus expression period.

Canine Mammary Tumor Cell Lines Derived from Metastatic Foci Show Increased RAD51 Expression but Diminished Radioresistance via p21 Inhibition.

Due to the high incidence of mammary tumors in dogs, it is important to elucidate the pathogenesis of these tumors in veterinary medicine. Radiation therapy is often used to treat mammary tumors that target DNA lesions. RAD51 is a key molecule that repairs DNA damage via homologous recombination. We examined the relationship between RAD51 expression and radiosensitivity in mammary tumor cell lines. CHMp and CHMm from the same individual were selected based on the differences in RAD51 expression. The radiosensitivity of both cell lines was examined using MTT and scratch assays; CHMm, which has high RAD51 expression, showed higher sensitivity to radiation than CHMp. However, the nuclear focus of RAD51 during DNA repair was formed normally in CHMp, but not in most of CHMm. Since irradiation resulted in the suppression of cell cycle progression in CHMp, the expression of p21, a cell cycle regulatory factor, was detected in CHMp after 15 Gy irradiation but not in CHMm. These results indicate that functional expression is more important than the quantitative expression of RAD51 in canine mammary tumor cells in response to DNA damage.

Evaluation of Prolonged Endometrial Inflammation Associated with the Periparturient Metabolic State in Dairy Cows.

The objectives of this study were to assess the sequential dynamics of the endometrial polymorphonuclear cells (PMN) after calving by endometrial cytology, and clarify the factors that cause prolonged endometrial inflammation in lactating dairy cows. A total of 33 lactating Holstein dairy cows were used from -4 to 8 wk relative to calving (0 wk: the calving week). Endometrial samples were obtained sequentially from 2 to 8 wk. Body condition score and backfat thickness were obtained weekly from -4 to 8 wk. Blood samples collected from -4 to 8 wk were analyzed for indicators of energy status, hepatic function, systemic inflammation, and calcium. Blood amino acids were measured at 2 wk. Daily milk production was determined between 5 and 65 d postpartum. Based on the sequential cytological analysis, the endometrial inflammation threshold was set at ≥5.0% PMN, and the median wk of PMN% lower than 5.0% was 4.5 wk in this study; therefore, we classified the cows into the early group (cows with endometrial inflammation converged within 4 wk: n = 17) and the late group (cows with endometrial inflammation converged at or after 5 wk: n = 16). There were no differences in daily milk production, energy status, hepatic function, blood calcium concentration, and systemic inflammatory response. The late group had lower body condition scores and backfat thickness during the experimental period, and a higher blood concentration of 3-methyl histidine, indicating muscle breakdown, was observed in the late group at 2 wk. Our findings indicated that the lack of body fat reservation during the peripartum period and the increased muscle breakdown after calving were risk factors for prolonged endometrial inflammation.

Ionophore Antibiotics Inhibit Type II Feline Coronavirus Proliferation In Vitro.

Feline coronaviruses (FCoVs) infect cats worldwide and cause severe systemic diseases, such as feline infectious peritonitis (FIP). FIP has a high mortality rate, and drugs approved by the Food and Drug Administration have been ineffective for the treatment of FIP. Investigating host factors and the functions required for FCoV replication is necessary to develop effective drugs for the treatment of FIP. FCoV utilizes an endosomal trafficking system for cellular entry after binding between the viral spike (S) protein and its receptor. The cellular enzymes that cleave the S protein of FCoV to release the viral genome into the cytosol require an acidic pH optimized in the endosomes by regulating cellular ion concentrations. Ionophore antibiotics are compounds that form complexes with alkali ions to alter the endosomal pH conditions. This study shows that ionophore antibiotics, including valinomycin, salinomycin, and nigericin, inhibit FCoV proliferation in vitro in a dose-dependent manner. These results suggest that ionophore antibiotics should be investigated further as potential broad-spectrum anti-FCoV agents.

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.

Allogeneic islet transplantation with monitoring of islet-specific cellular autoimmunity in a Japanese patient with type 1 diabetes: A case report.

Here, we report a case of allogeneic islet transplantation in Japan. A 48-year-old man received intraportal islet transplantation (5,945 islet equivalent/kg), and stabilization of blood glucose levels and suppression of hypoglycemia were achieved. In the present case, we used our original assessment method to detect the responses of the recipient's T cells to islet autoantigens over time to monitor cellular autoimmunity. Other markers could not predict graft dysfunction in advance, but our method detected the activation of islet antigen-specific CD8+ T-cell responses before the deterioration of pancreatic ß-cell function, indicating the possibility of the non-invasive detection of pancreatic ß-cell damage due to recurrent autoimmunity.

Computed tomography-guided lymphangiography from the para-aortic lymph node: a useful approach for chylothorax after esophagectomy.

BACKGROUND: Chylothorax is a relatively rare complication of esophagectomy but can lead to fatal conditions. The aim of this report was to present a case of lymphangiography from the para-aortic lymph node (PALN) under computed tomography (CT) guidance, which could be an alternative modality to ultrasound sonography from the groin. CASE PRESENTATION: A 58-year-old man was diagnosed as having postoperative chylothorax after esophagectomy following neoadjuvant chemotherapy. As the pleural effusion did not improve, intranodal lipiodol lymphangiography from the inguinal lymph node was performed but was unsuccessful. Therefore, CT-guided lymphangiography from the left PALN was performed, and the pleural effusion drainage significantly disappeared. CONCLUSIONS: CT-guided lipiodol lymphangiography from the PALN for chylothorax after esophagectomy was safe and thus can be considered an alternative treatment option to ultrasonography-guided intranodal lymphangiography. The flexible use of CT and ultrasonography for lymphangiography may improve the treatment outcomes of chylothorax after esophagectomy.

Clinical and radiological findings of silent hypoxia among COVID-19 patients.

The aim of this study was to describe the clinical and radiological findings of COVID-19 patients with "silent hypoxia," who had no dyspnea on admission even though their oximetry saturation was less than 94%. This retrospective cohort study included all COVID-19 patients (n = 270) at a large tertiary care hospital between January 31 and August 31, 2020. Clinical and radiological characteristics of patients who met our criteria of "silent hypoxia", which included those who reported no dyspnea even though oximetry saturation was <94%, were extracted. Eight patients (3.0%) met the criteria for "silent hypoxia." The median age was 61 years (interquartile range [IQR]: 48.8-72.3), and five (62.5%) were men. All patients had consolidation on CT and showed a moderate to high COVID-19 CT severity score (median: 13.5, IQR: 10.8-15.3). The median FIO2 of the maximum oxygen required was 55 (IQR: 28-70)%. Two patients (25.0%) were intubated, and one patient (12.5%) underwent extracorporeal membrane oxygenation. Some COVID-19 patients with "silent hypoxia" may develop severe disease. Close and accurate monitoring of patients using arterial blood gas and pulse oximetry is necessary, regardless of their symptoms.

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.

Mid-term outcome of transarterial embolization of renal artery pseudoaneurysm and arteriovenous fistula after partial nephrectomy screened by early postoperative contrast-enhanced CT.

PURPOSE: To retrospectively evaluate the mid-term outcome of transarterial embolization (TAE) of renal artery pseudoaneurysm (RAP) including arteriovenous fistula (AVF) after partial nephrectomy screened by early postoperative contrast-enhanced CT (CE-CT). MATERIALS AND METHODS: Eighty-two patients (7.0%) who underwent TAE after partial nephrectomy were reviewed, from 1166 partial nephrectomies performed over 6 years. In 18 patients (22.0%), TAE was performed emergently on the median postoperative day (POD) seven. In the remaining patients, elective TAE was performed on the median POD six for RAP detected by early postoperative CE-CT or that emerged on follow-up CE-CT. RESULTS: In one patient (1.2%), TAE was performed twice because one of two RAPs could not be embolized during the first TAE, being successfully embolized at the second TAE after readmission with hematuria. Otherwise, no bleeding recurrence or RAPs were observed during the median 1354 follow-up days. Thus, the primary and secondary success rates of TAE were 98.8% (81 of 82 patients) and 100% (82 of 82 patients), respectively. On angiography, the average number of lesions was 1.7 ± 0.9 and the average RAP size was 12.8 ± 6.0 mm. The shapes of the lesions varied: oval-round 60, oval-round + AVF 36, irregular + AVF 14, AVF 12, irregular 10, disruption 4, and extravasation 3. No major complications were observed. The median inpatient days after TAE were two. No estimated glomerular filtration rate deterioration was observed (64.6 ± 18.6 vs. 64.2 ± 18.4 mL/min/1.73 m2, p = 0.902). CONCLUSION: TAE is largely effective and safe for treating bleedings or RAPs, including AVFs, after partial nephrectomy, as screened by early postoperative CE-CT.

Pseudomyxoma peritonei: visceral scalloping on CT is a predictor of recurrence after complete cytoreductive surgery.

OBJECTIVES: Pseudomyxoma peritonei (PMP) is characterized by peritoneal dissemination of gelatinous ascites following rupture of a mucinous tumor. Treatment by cytoreductive surgery (CRS) has improved its prognosis. Although visceral scalloping, notably liver scalloping, on computed tomography (CT) is a typical feature of PMP, its prognostic value remains unknown. We aimed to investigate the efficacy of liver scalloping in predicting recurrence in PMP patients. METHODS: Among 159 consecutive patients with PMP who had contrast-enhanced CT between September 2012 and December 2018, 64 treatment-naïve patients who subsequently underwent CRS with complete resection (i.e., completeness of cytoreduction score (CC)-0 or CC-1), were included in analysis. Presence of liver scalloping and maximum thickness of mucin deposition at the liver surface were evaluated on CT. Disease-free survival (DFS) was determined based on the combination of postoperative CT features and tumor marker values. RESULTS: Median follow-up was 24.3 months. CT revealed liver scalloping in 40/64 (63.4%) patients. Kaplan-Meier analysis showed significantly shorter DFS in patients with scalloping than in those without (p = 0.001; hazard ratio, 4.3). In patients with scalloping, greater mucin deposition (thickness ≥ 20 mm) significantly correlated with poorer DFS (p = 0.042). In multivariate Cox proportional hazards regression including CC status, pathologic type, and tumor markers, the presence of scalloping independently and significantly correlated with DFS (p = 0.031). CONCLUSIONS: Liver scalloping was an independent predictor even after adjusting for clinical covariates. The presence of liver scalloping can lead to a high recurrence rate after CRS. KEY POINTS: • The presence of liver scalloping is a prognostic factor independent of histological grade and tumor markers. • Greater mucin deposition (thickness ≥ 20 mm at the liver surface) is associated with higher recurrence rates in patients with liver scalloping.

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.