Liver regeneration after portal vein embolization: comparison between absolute ethanol and N-butyl-cyanoacrylate in an in vivo rat model.

PURPOSE: To compare the effects of absolute ethanol (ethanol) and N-butyl-cyanoacrylate (NBCA) on non-embolized liver lobe regeneration in a rat model. METHODS: Twenty-seven Sprague-Dawley rats underwent portal vein embolization (PVE) using ethanol:lipiodol, 1:1 (ethanol group, n = 11, 40.74%), NBCA:lipiodol, 1:1 (NBCA group, n = 11, 40.74%), or sham treatment (sham group, n = 5, 18.52%). The non-embolized and embolized lobe-to-whole liver weight ratios 14 days after PVE were compared among the groups (n = 5, 18.52%). The expressions of CD68 and Ki-67 and embolized-lobe necrotic area percentages one day after PVE were compared between the ethanol (n = 3, 11.11%) and NBCA (n = 3, 11.11%) groups. RESULTS: The non-embolized lobe-to-whole liver weight ratio after PVE was significantly higher in the NBCA group (n = 5, 33.33%) than in the ethanol group (n = 5, 33.33%) (84.28% ± 1.53% vs. 76.88% ± 4.12%, P = 0.029). The embolized lobe-to-whole liver weight ratio after PVE was significantly lower in the NBCA group than in the ethanol group (15.72% ± 1.53% vs. 23.12% ± 4.12%, P = 0.029). The proportions of CD68- and Ki-67-positive cells in the non-embolized lobe after PVE were significantly higher in the NBCA group (n = 30, 50%) than in the ethanol group (n = 30, 50%) [60 (48-79) vs. 55 (37-70), P = 0.003; 1 (0-2) vs. 1 (0-2), P = 0.004]. The embolized-lobe necrotic area percentage after PVE was significantly larger in the NBCA group (n = 30, 50%) than in the ethanol group (n = 30, 50%) [29.46 (12.56-83.90%) vs. 16.34 (3.22-32.0%), P < 0.001]. CONCLUSION: PVE with NBCA induced a larger necrotic area in the embolized lobe and promoted greater non-embolized liver lobe regeneration compared with PVE with ethanol.

Clinicoradiological Characteristics of Gastric Metastases: A Single Center Retrospective Study.

BACKGROUND:  With recent advances in treatment, gastric metastases are increasingly becoming the subject of diagnostic imaging. On the other hand, it is difficult to detect gastric metastasis on CT finding images. PURPOSE:  To characterize the CT findings of gastric metastasis and investigate its treatment method and natural history in patients. MATERIALS AND METHODS:  We retrospectively reviewed the CT findings of 15 patients diagnosed with gastric metastasis between April 2003 and December 2019 in our hospital. The location, size, and shape of the tumors on CT were evaluated. Moreover, their medical records, characteristics, complications, treatment options, and natural course were evaluated. RESULTS:  Of the 15 patients with gastric metastasis, 9 were male and 6 were female. The median age was 74 (55-87) years. Gastric metastasis was diagnosed simultaneously with primary cancer in five patients. In other patients, the median interval time from the date of primary cancer diagnosis to gastric metastasis diagnosis was 27 (10-259) months. CT findings revealed that the gastric metastasis had a median size of 18 (12-135) mm and was mainly located in the middle third of the stomach. In addition, most patients had a submucosal tumor (SMT) pattern, followed by diffuse wall thickness and polypoid patterns (11 [73.3%], 3 [20.0%], and 1 [6.7%], respectively). The median time to death after gastric metastasis diagnosis was 112 (17-883) days. CONCLUSION:  The SMT pattern in the middle third of the stomach is the characteristic CT finding of gastric metastasis.

Increased future liver function after modified associating liver partition and portal vein ligation/embolization for staged hepatectomy.

Background: The increasing ratio of functional future liver remnant (functional %FLR) after modified associating liver partition and portal vein ligation/embolization for staged hepatectomy (modified-ALPPS) compared with portal vein embolization (PVE) has not been comprehensively evaluated. Purpose: To compare the increasing ratio of functional %FLR between modified-ALPPS and PVE via technetium-99 m-galactosyl human serum albumin single-photon emission computed tomography (99mTc-GSA SPECT/CT) fusion imaging. Material and Methods: Seven and six patients underwent modified-ALPPS (modified-ALPPS group) and PVE (PVE group) from 2015 to 2019. The functional %FLR on 99 mTc-GSA SPECT/CT fusion imaging was assessed before and 1 week (modified-ALPPS group) and 3 weeks (PVE group) after each procedure. The increasing ratio of functional %FLR (functional %FLR ratio) was calculated and compared between the two groups. Moreover, the hypertrophy ratio of future liver remnant volume (FLRV ratio) and atrophy ratio of embolized liver volume (.ELV ratio) were evaluated. Results: The mean functional %FLR ratios of the modified-ALPPS group (1.47 ± 0.15) and the PVE group (1.49 ± 0.20) were comparable (p > .05). The median FLRV ratio of modified-ALPPS group (1.48) was higher than that of the PVE group (1.16), the median ELV ratio of the PVE group (0.81) was lower than that of the modified-ALPPS group (0.94), and the results significantly differed between the two groups (p < .05). Conclusion: The increasing ratio of functional %FLR was comparable between modified-ALPPS and PVE. Compared with PVE, ALPPS was associated with a higher hypertrophy rate of the remnant liver but a lower atrophy rate of the embolized liver.

Pseudohemothorax induced by residual contrast medium mimicking aortic dissection rupture.

Hemothorax is an urgent condition, and its accurate diagnosis and the identification of the cause are important. Herein, we report a case of a 74-year-old man with end-stage renal disease who was presented with high-concentration pleural effusion owing to residual contrast medium. The case required differentiation from hemothorax owing to an aortic dissection and its rupture. In patients with end-stage renal disease, noncontrast-enhanced computed tomography after contrast-enhanced computed tomography may result in high-concentration pleural effusion owing to the existence of residual contrast medium. This realization is important to determine whether high-concentration pleural effusion symptoms reflect an urgent hemothorax case possibly related to an imminent rupture of an aortic aneurysm or intrathoracic penetration of aortic dissection, and whether invasive procedures, such as thoracentesis, ought to be avoided.

Inverted intercostal hernia of elastofibroma dorsi mimicking well-differentiated liposarcoma in the chest wall.

Elastofibroma dorsi is a well-known benign chest wall tumor. Herein, we present a case in which an elastofibroma protruded into the thoracic cavity, leading to inverted intercostal hernia. Imaging revealed a soft tissue mass containing fat, typical of elastofibroma dorsi; however, precise diagnosis was difficult owing to the location of this mass that protruded into the thoracic cavity. Liposarcoma had to be ruled out because it was a growing fat-containing mass. Considering that the tumor moved while the patient was undergoing computed tomography-guided biopsy in the prone position, a diagnosis of inverted intercostal hernia of elastofibroma dorsi was made. We report this case with a review of current literature.

T2 hypointense signal discovered incidentally at the posterior edge of the adenohypophysis on MRI: its prevalence and morphology and their relationship to age.

PURPOSE: T2 hypointense signal at the posterior edge of the adenohypophysis (T2HSPA) on magnetic resonance imaging (MRI) is incidentally encountered. We aimed to investigate the prevalence and morphology of T2HSPA and their relationship to age. METHODS: A total of 212 cases between 3 and 88 years old were examined. Sagittal T2-weighted image (T2WI) was evaluated for the presence of T2HSPA, which classified by its morphology into two types (belt-like or nodal). The Wilcoxon rank sum test and chi-square test were used to evaluate the differences between the groups. The T2HSPA was extracted by ImageJ software and measured as a cross-sectional area (CSA) quantitatively by threshold setting. We examined the relationship between CSA of T2HSPA and age, and Spearman's correlation coefficients were used for statistical analysis. RESULTS: Of the 212 cases, 80 (37.7%) were identified with T2HSPA. The groups with T2HSPA were significantly younger than the groups without it (p = .01). Groups with belt-like T2HSPA were significantly younger than the groups with nodal T2HSPA (p = .01). There was a weak negative correlation between CSA of T2HSPA and age (p = .02). CONCLUSION: T2HSPAs were incidentally detected in 37.7% of all cases, tended to be more common in younger cases, and their morphology was related to age. They seem to have little clinical significance as they tend to decrease in size with age.

Multiscale Entropy of Resting-State Functional Magnetic Resonance Imaging Differentiates Progressive Supranuclear Palsy and Multiple System Atrophy.

Distinguishing progressive supranuclear palsy (PSP) from multiple system atrophy (MSA) in the early clinical stages is challenging; few sensitive and specific biomarkers are available for their differential diagnosis. Resting-state functional magnetic resonance imaging (rs-fMRI) is used to study the fluctuations in blood oxygen level-dependent (BOLD) signals at rest, which provides evidence for aberrant brain functional networks in neurodegenerative diseases. We aimed to examine whether rs-fMRI data could differentiate between PSP and MSA via a multiscale entropy (MSE) analysis of BOLD signals, which estimates the complexity of temporal fluctuations in brain activity. We recruited 14 and 18 patients with PSP and MSA, respectively, who underwent neuropsychological tests and rs-fMRI. PSP patients demonstrated greater cognitive function impairments, particularly in the frontal executive function. The bilateral prefrontal cortex revealed lower entropy BOLD signal values in multiple time scales for PSP, compared to the values observed in MSA patients; however, the functional connectivity of the representative brain networks was comparable between the diseases. The reduced complexity of BOLD signals in the prefrontal cortex was associated with frontal dysfunction. Thus, an MSE analysis of rs-fMRI could differentiate between PSP and MSA, and the reduced complexity of BOLD signals could be associated with cognitive impairment.

Magnetic Resonance Spectroscopy in the Ventral Tegmental Area Distinguishes Responders to Suvorexant Prior to Treatment: A 4-Week Prospective Cohort Study.

Background: The ventral tegmental area (VTA; a dopaminergic nucleus) plays an important role in the sleep-wake regulation system including orexin system. In addition to neuronal activity, there is increasing evidence for an important role of glial cells (i.e., astrocytes and microglia) in these systems. The present study examined the utility of magnetic resonance spectroscopy (MRS) for detecting neural and/or glial changes in the VTA to distinguish responders from non-responders before treatment with the orexin receptor antagonist suvorexant. Methods: A total of 50 patients were screened and 9 patients were excluded. The remaining 41 patients with insomnia who have or not a psychiatric disease who were expected to receive suvorexant treatment were included in this study. We compared MRS signals in the VTA between responders to suvorexant and non-responders before suvorexant use. Based on previous reports, suvorexant responders were defined as patients who improved ≥3 points on the Pittsburgh Sleep Quality Index after 4 weeks of suvorexant use. MRS data included choline (reflects non-specific cell membrane breakdown, including of glial cells) and N-acetylaspartate (a decrease reflects neuronal degeneration). Results: Among 41 examined patients, 20 patients responded to suvorexant and 21 patients did not. By MRS, the choline/creatine and phosphorylcreatine ratio in the VTA was significantly high in non-responders compared with responders (p = 0.039) before suvorexant treatment. There was no difference in the N-acetylaspartate/creatine and phosphorylcreatine ratio (p = 0.297) between the two groups. Conclusions: Changes in glial viability in the VTA might be used to distinguish responders to suvorexant from non-responders before starting treatment. These findings may help with more appropriate selection of patients for suvorexant treatment in clinical practice. Further, we provide novel possible evidence for a relationship between glial changes in the VTA and the orexin system, which may aid in the development of new hypnotics focusing on the VTA and/or glial cells.

Osteoid osteoma of the rib with strong F-18 fluoro-deoxyglucose uptake mimicking osteoblastoma: a case report with literature review.

Osteoid osteoma is a benign osteoblastic bone lesion, characterized by nocturnal pain alleviated by salicylates or nonsteroidal anti-inflammatory drugs. This tumor distinctly affects the long bones, typically the femur or tibia and is rarely located in the ribs. Usually, this tumor is usually diagnosed by computed tomography or magnetic resonance imaging, but F-18 fluoro-deoxyglucose positron emission tomographic (FDG-PET)/computed tomography is usually negative and is not used for diagnosis. We recently encountered a case of an osteoid osteoma located in the rib of 44-year-old Asian male with strong FDG uptake as high as 12.0 at the maximum standardized uptake value at FDG-PET/computed tomography. His computed tomography and magnetic resonance imaging showed osteosclerosis, bone marrow edema, and edema of surrounding tissues not only in the bone with nidus but also in the adjacent bone, and pathological findings showed strong infiltration munched radiology. Strong FDG uptake mimicking osteoblastoma. Osteoid osteoma with strong FDG uptake suggested a strong inflammatory response.

[Accuracy of Classification of Cerebral Blood Flow Reduction Patterns Using Statistical Analysis Images Generated with Simulated SPECT Datasets via Deep Learning].

PURPOSE: The aim of this study was to evaluate the classification accuracy of specific blood flow reduction patterns in clinical images by deep learning using simulation data. METHODS: We obtained Z-score maps for 100 cases each of simulated Alzheimer's disease (AD), simulated dementia with Lewy bodies (DLB), and simulated normal cognition (NC) by performing statistical analysis of the simulation data that provided defects and healthy patient data. The clinical images were determined by reference to radiological reports, and Z-score maps of AD (n=33), DLB (n=20), and NC (n=28) were used. A network was constructed with reference to AlexNet, 4-fold cross-validation was performed using only simulation data, and classification accuracy was evaluated. We also trained the model using the simulation data and classified the clinical images. RESULTS: The accuracy rate of classification between simulations was 96.2% and that of the clinical images was 84.2%. CONCLUSION: Through deep learning using simulation data, clinical images may be classified with an accuracy of 84.2%.

Coil volume embolization ratio for preventing recanalization after portal vein embolization.

PURPOSE: The purpose of this study was to evaluate the optimum volume embolization ratio (VER) for the prevention of recanalization after portal vein embolization (PVE) and the influence of recanalization on future liver remnant (FLR) function using technetium-99m galactosyl human serum albumin single-photon emission computed tomography (99mTc-GSA SPECT/CT) fusion imaging. METHODS: We analyzed procedural data of 18 patients who underwent PVE from 2015 to 2018. A total of 29 portal branches were embolized (12 anterior branch, 11 posterior branch, 4 left branch, 2 right branch) with absolute ethanol and coils. Portal vein recanalization was evaluated three weeks after PVE by contrast-enhanced CT. We classified the treated portal branches as non-recanalized and recanalized. VER was compared between the groups. In addition, for each patient, we calculated and evaluated the ratio of FLR volume to total liver volume (volumetric %FLR), FLR count to total liver count on 99mTc-GSA SPECT/CT fusion imaging (functional %FLR), and functional-volumetric ratio (functional %FLR/ volumetric %FLR). RESULTS: Twenty-six portal branches showed no recanalization (non-recanalized group, n=26, 89.7%), while three portal branches showed recanalization (recanalized group, n=3, 10.3%). The median VER was 4.94% (3.12%-11.1%) in the non-recanalized group and 3.49% (2.76%-4.32%) in the recanalized group, which was significantly different between the groups (p = 0.045, Mann-Whitney U test). The median functional-volumetric ratio was 1.16 (1.03-1.50) in non-recanalized patients (n=15, 83.3%) and 1.01 (0.96-1.13) in recanalized patients (n=3, 16.7%), and it was significantly higher in the non-recanalized patients (p = 0.021, Mann-Whitney U test). CONCLUSION: The VER for preventing recanalization after PVE was approximately 5% (> 4.94%). 99mTc-GSA SPECT/CT fusion imaging revealed a decrease in FLR function due to recanalization after PVE.

Comparison between turbo spin-echo and echo planar diffusion-weighted imaging of the female pelvis with 3T MRI.

BACKGROUND: Echo-planar imaging (EPI)-diffusion-weighted imaging (DWI) may take unclear image affected by susceptibility, geometric distortions and chemical shift artifacts. PURPOSE: To compare the image quality and usefulness of EPI-DWI and turbo spin echo (TSE)-DWI in female patients who required imaging of the pelvis. MATERIAL AND METHODS: All 57 patients were examined with a 3.0-T MR scanner. Both TSE- and EPI-DWI were performed with b values of 0 and 1000 s/mm2. We compared geometric distortion, the contrast ratio (CR) of the myometrium to the muscle and the apparent diffusion coefficient (ADC) values for the myometrium and lesion. Two radiologists scored the TSE- and EPI-DWI of each patient for qualitative evaluation. RESULTS: The mean percent distortion was significantly smaller with TSE- than EPI-DWI (p = 0.00). The CR was significantly higher with TSE- than EPI-DWI (p = 0.003). There was a significant difference in the ADC value for the uterus and lesions between the EPI- and TSE-DWI (p < 0.05). Finally, the ADC values of cancer were significantly different from those for the uterus and benign with both the two sequences (p < 0.05). The scores for ghosting artifacts were higher with TSE- than EPI-DWI (p = 0.019). But there were no significant differences between TSE- and EPI-DWI with regard to image contrast and overall image quality. CONCLUSION: TSE-DWI on the female pelvis by 3T MRI produces less distortion and higher CR than EPI-DWI, but there is no difference in contrast and image quality.

CT-guided color marking of impalpable pulmonary nodules prior to video-assisted thoracoscopic surgery.

OBJECTIVES: To investigate the utility and complications of computed tomography (CT)-guided color marking of impalpable pulmonary nodules for video-assisted thoracoscopic surgical resection. METHODS: This retrospective single institutional study has obtained Institutional Review Board approval. A total of 174 patients with 207 undiagnosed peripheral lesions of the lung were enrolled who had undergone preoperative computed tomography-guided color marking using colored collagen followed by video-assisted thoracoscopic surgery (VATS) from December 2015 to September 2018. RESULTS: All nodules (mean 14.0 mm, range 3.0-30.0 mm) were successfully marked by computed tomography-guided color marking, and 96.0% cases (167/174) were localized by means of intraoperative fluoroscopy as clear spots. Minor pneumothorax with a median volume of 3.8 mL (range 0.2-119.0 mL) occurred in 12 patients (6.9%) who were completely asymptomatic and were not in serious condition. No patient required a chest tube. No major bleeding complication occurred, and no air emboli were seen. No intra- or post-operative mortality of VATS was observed. CONCLUSIONS: Preoperative CT-guided color marking of impalpable pulmonary nodules is a safe and effective procedure that allows for successful surgical resection.

Double Dose Reduction in the Equilibrium Phase of Chest-Pelvic CT With Low Tube Voltage and Forward-Projected Model-Based Iterative Reconstruction Solution.

Objectives This study aimed to examine whether a new imaging method (80-kV forward-projected model-based iterative reconstruction solution [FIRST] protocol) that uses a combination of low tube voltage and FIRST can reduce radiation dose and contrast medium volume by comparing the quality of the resulting image with that of the image obtained by 120-kV adaptive iterative dose reduction 3D protocol in the equilibrium phase of chest-pelvic computed tomography (CT). Subjects and methods Twenty-seven patients underwent CT by both protocols on different days. Two radiologists subjectively assessed image quality by scoring axial images for sharpness, contrast enhancement, noise, artifacts, and overall quality. The mean CT values, standard deviations, contrast-to-noise ratios, and signal-to-noise ratios in the liver, aorta, and erector spinae muscles were used for objective assessment. Radiation dose parameters included the CT dose index volume, dose-length product, effective dose, and size-specific dose estimate. Results were compared for different body mass index categories. Results The 80-kV FIRST protocol helped achieve mean reductions of 36.3%, 35.7%, and 36.6% in CT dose index volume, effective dose, and size-specific dose estimate, respectively (p < 0.01). Therefore, this protocol was regarded as comparable to the conventional protocol in image quality, except for visual sharpness. Conclusions The 80-kV FIRST protocol is capable of reducing radiation dose and contrast medium volume compared to the adaptive iterative dose reduction 3D protocol in the equilibrium phase of chest-pelvic CT.

Diagnosis of a small Leydig cell tumor by dynamic contrast-enhanced and diffusion-weighted magnetic resonance imaging.

Leydig cell tumors are usually small and resemble normal ovarian stroma, so they are often difficult to localize. Here, we present a rare case in 39-year-old woman which dynamic contrast-enhanced and diffusion-weighted magnetic resonance imaging findings showed some differences between a Leydig cell tumor and normal ovarian stroma. Combining these 2 MRI techniques may be useful for diagnosing a Leydig cell tumor.

Gossypiboma penetrating into the small intestine similar to Meckel's diverticulum: a report and literature review.

Foreign body granuloma due to retained surgical sponge (gossypiboma) with penetration into the small intestine is very rare. Cases of gossypiboma in the abdominal cavity have sometimes been reported, yet the correct incidence has not been determined, only estimated to occur in one of every 1,000 to 1,500 intra-abdominal operations. Acute abdomen may be observed in some cases, requiring treatment. We herein introduce the case of a 70-year-old woman with gossypiboma penetrating into the small intestine presented with anemia and hematochezia. She had a history of emergency laparotomy for ectopic pregnancy several decades ago. A dynamic contrast-enhanced computed tomography revealed a hypovascular mass containing air bubbles that continued to the small intestine approximately 50 mm in size in the right lower abdomen. In addition to describing the presentation and outcome of our patient, we review the image findings of gossypiboma.

Dynamic CT findings of a polypoid gastric metastasis of clear renal cell carcinoma: a case report with literature review.

Metastatic disease involving the stomach is very rare. The gastric metastases of renal cell carcinoma (RCC) have rarely been reported, occurring in 0.2% of all RCC cases. Sometimes gastric metastases cause gastrointestinal bleeding and require treatment. We present the case of an 85-year-old woman with gastric metastasis from RCC diagnosed by anemia and bleeding. A dynamic contrast-enhanced computed tomography revealed a pedunculated and hypervascular polypoid mass approximately 100 mm in size with a washout enhancement pattern in the stomach. In addition to describing the case of our patient, we have reviewed computed tomography findings of gastric metastases from clear RCC.

Pulmonary Actinomycosis Mimicking Pulmonary Cancer on Fluorine-18 Fluorodeoxyglucose PET-CT.

Pulmonary actinomycosis is a rare disease frequently misdiagnosed as primary lung cancer. Herein, we presented pulmonary actinomycosis mimicking pulmonary cancer on fluorine-18 fluorodeoxyglucose (F-18-FDG) PET-CT.