In vitro Demonstration of Melanoma Metastasis in Lymph Nodes of Prepared Specimens Using a Light-emitting Diode-based Multispectral Photoacoustic Ultrasound Imaging System.

Although an excellent photoacoustic (PA) ultrasound method has been reported for the evaluation of lymph node melanoma metastasis in animal experiments, it remains to be evaluated in clinical trials. Recently, we performed PA ultrasound assessment using light-emitting diodes to detect metastatic melanoma in the lymph nodes of specimens prepared for microscopic examination. The PA effect was not obvious in amelanotic melanoma, but was seen in melanotic melanoma by PA imaging (PAI) and histopathological correlation in cases of primary melanotic melanoma accompanied by metastatic lymph nodes, including the coexistence of amelanotic melanoma and melanotic melanoma. Clinical workup should be performed with not only PAI but also conventional ultrasonography in cases with metastasis related to amelanotic transformation, which would likely be missed by PAI alone.

Optimal diagnostic method using multidetector-row computed tomography for predicting lymph node metastasis in colorectal cancer.

BACKGROUND: Prediction of nodal involvement in colorectal cancer is an important aspect of preoperative workup to determine the necessity of preoperative treatment and the adequate extent of lymphadenectomy during surgery. This study aimed to investigate newer multidetector-row computed tomography (MDCT) findings for better predicting lymph node (LN) metastasis in colorectal cancer. METHODS: Seventy patients were enrolled in this study; all underwent MDCT prior to surgery and upfront curative resection for colorectal cancer. LNs with a short-axis diameter (SAD) ≥ 4 mm were identified on MDCT images, and the following measures were recorded by two radiologists independently: two-dimensional (2D) SAD, 2D long-axis diameter (LAD), 2D ratio of SAD to LAD, 2D CT attenuation value, three-dimensional (3D) SAD, 3D LAD, 3D SAD to LAD ratio, 3D CT attenuation value, LN volume, and presence of extranodal neoplastic spread (ENS), as defined by indistinct nodal margin, irregular capsular enhancement, or infiltration into adjacent structures. RESULTS: Forty-six patients presented 173 LNs with a SAD ≥ 4 mm, while 24 patients exhibited pathologically confirmed LN metastases. Receiver operating characteristic analysis revealed that 2D LAD was the most sensitive measure for LN metastases with an area under the curve of 0.752 (cut-off value, 7.05 mm). When combined with CT findings indicating ENS, 2D LAD (> or ≤ 7 mm) showed enhanced predictive power for LN metastases (area under the curve, 0.846; p < 0.001). CONCLUSIONS: LAD in axial MDCT imaging is the most sensitive measure for predicting colorectal LN metastases, especially when MDCT findings of ENS are observed.

Acute Mesenteric Ischemia: Multidetector CT Findings and Endovascular Management.

Acute mesenteric ischemia is a rare life-threatening condition that accounts for approximately one in 1000 hospital admissions. The mortality rate is 50%-69% owing to the absence of specific symptoms and laboratory data, which makes early detection of this condition difficult. If the use of contrast material is possible, biphasic contrast material-enhanced multidetector computed tomography (CT) is the first-line imaging test for early diagnosis of the disease and for differentiation from other causes of acute abdomen. Multidetector CT can depict mesenteric ischemia, its underlying causes, and its severity. Mesenteric ischemia is classified as either acute or chronic. The causes of AMI include arterial embolism, arterial thrombosis, venous thrombosis, and nonocclusive mesenteric ischemia, among which arterial causes are far more common than venous causes. Recently, endovascular procedures such as thrombolysis, thrombectomy, thrombus fragmentation, and stent placement have been successfully and safely performed when the ischemia is reversible. Online DICOM image stacks are available for this article. ©RSNA, 2018.

Identification of the reporter gene combination that shows high contrast for cellular level MRI.

Currently, we can label the certain cells by transducing specific genes, called reporter genes, and distinguish them from other cells. For example, fluorescent protein such as green fluorescence protein (GFP) is commonly used for cell labeling. However, fluorescent protein is difficult to observe in living animals. We can observe the reporter signals of the luciferin-luciferase system from the outside of living animals using in vivo imaging systems, although the resolution of this system is low. Therefore, in this study, we examined the reporter genes, which allowed the MRI-mediated observation of labeled cells in living animals. As a preliminary stage of animal study, we transduced some groups of plasmids that coded the protein that could take and store metal ions to the cell culture, added metal ions solutions, and measured their T1 or T2 relaxation values. Finally, we specified the best reporter gene combination for MRI, which was the combination of transferrin receptor, DMT1, and Ferritin-M6A for T1WI, and Ferritin-M6A for T2WI.

Utilizing Dynamic Phosphorous-31 Magnetic Resonance Spectroscopy for the Early Detection of Acute Compartment Syndrome: A Pilot Study on Rats.

INTRODUCTION: Disasters, including terrorism and earthquakes, are significant threats to people and may lead to many people requiring rescue. The longer the rescue takes, the higher the chances of an individual contracting acute compartment syndrome (ACS). ACS is fatal if diagnosed too late, and early diagnosis and treatment are essential. OBJECTIVE: To assess the ability of dynamic phosphorus magnetic resonance spectroscopy (31P-MRS) in the early detection of muscular damage in ACS. MATERIALS AND METHODS: Six ACS model rats were used for serial 31P-MRS scanning (9.4 Tesla). Skeletal muscle metabolism, represented by the levels of phosphocreatine (PCr), inorganic phosphate (Pi), and adenosine triphosphate (ATP), was assessed. The PCr/(Pi + PCr) ratio, which decreases with ischemia, was compared with simultaneously sampled plasma creatine phosphokinase (CPK), a muscle damage marker. RESULTS: The PCr/(Pi + PCr) ratio significantly decreased after inducing ischemia (from 0.86 ± 0.10 to 0.18 ± 0.06; p < 0.05), while CPK did not change significantly (from 89 ± 29.46 to 241.50 ± 113.28; p > 0.05). The intracellular and arterial pH index decreased over time, revealing significant differences at 120 min post-ischemia (from 7.09 ± 0.01 to 6.43 ± 0.13, and from 7.47 ± 0.03 to 7.39 ± 0.04, respectively). In the reperfusion state, the spectra and pH did not return to the original values. CONCLUSIONS: The dynamic 31P-MRS technique can rapidly detect changes in muscle bioenergetics. This technique is a promising non-invasive method for determining early muscular damage in ACS.

Multicenter Prospective Study of Color Doppler Ultrasound for Breast Masses: Utility of Our Color Doppler Method.

The use of color Doppler ultrasound (CD) for distinguishing between benign and malignant breast lesions remains controversial. This study (JABTS BC-04 study) was aimed at confirming the usefulness of our CD diagnostic criteria. We evaluated ultrasound images of 1408 solid breast masses from 16 institutions in Japan (malignant: 839, benign: 569). Multivariate analysis indicated that vascularity (amount of blood flow), vascular flow pattern ("surrounding marginal flow" or "penetrating flow") and the incident angle of penetrating flow were significant findings for distinguishing between benign and malignant lesions. However, the sensitivity and specificity of B-mode alone did not improve significantly with CD addition (97.6% → 97.9%, 38.3% → 41.5%, respectively). We explored the causes of these negative results and found that age should have been considered when evaluating vascularity. Simulation experiments suggested that specificity is significantly improved when age is taken into consideration (38.3% → 46.0%, p < 0.001) and we thereby improved our diagnostic criteria.

Significance of perithyroidal lymph nodes in benign thyroid diseases.

PURPOSE: The incidences of perithyroidal lymph nodes (PTLNs) in benign thyroid diseases were investigated. METHODS: A total of 108 patients were divided into 36 with benign thyroid nodules, 33 with Hashimoto's thyroiditis, 14 with Graves' disease, 10 with hypothyroidism of undetermined etiology, nine with silent thyroiditis, and six with subacute thyroiditis. We assessed the relationships among PTLNs and these groups, thyroid volume, thyroid parenchyma echogenicity, and anti-thyroid-stimulating hormone receptor, anti-thyroglobulin, and anti-thyroid peroxidase antibodies (TRAb, TgAb, and TPOAb). RESULTS: The PTLN-positive rates in Hashimoto's thyroiditis (69.7%), subacute thyroiditis (83.8%), silent thyroiditis (77.8%), and Graves' disease (35.7%) groups were significantly higher than those in benign thyroid nodules (5.6%) and hypothyroidism of unknown etiology (0%) groups. The PTLN-positive rates were significantly higher in cases with TgAb and/or TPOAb (P < 0.01) and in those with lower parenchyma echogenicity (P < 0.01). CONCLUSION: PTLNs were seen in inflammatory thyroid diseases, but were rarely detected in other thyroid diseases. These findings indicate that PTLNs are an indicator for differentiating inflammation of the thyroid. Lower echogenicity of the thyroid, known to correspond to inflammation, showed a correlation with the positive rate of PTLNs. PTLNs in cases of Graves' disease may be due to coexisting thyroiditis related to TgAb and/or TPOAb.