Modulation transfer function of digital breast tomosynthesis: a comparison of various edge devices.

The modulation transfer function (MTF) is a fundamental tool for assessing the sharpness of digital breast tomosynthesis (DBT) systems and is primarily measured using edge devices. We compared the MTF of a Senographe Pristina DBT system using four-edge devices. These devices were composed of stainless steel with a thickness of 0.6, 0.8, and 1.0 mm, and 1.0 mm tungsten, based on different international guidelines. We evaluated spatial frequencies at MTFs of 0.5 (MTF50%) and 0.1 (MTF10%). The collimator-equipped and non-collimator configurations of the DBT were compared. We found no appreciable differences between scan and chest wall-nipple directions. Both MTF50% (2.90-2.99 cycles/mm) and MTF10% (6.69-6.94 cycles/mm) demonstrated minimal variation across the different edge devices. The collimator-equipped system exhibited an MTF50% that was approximately 5% higher than that of the non-collimator configuration. The choice of the edge device did not appreciably impact the MTF.

Liver function test by gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging with consideration of intrahepatic regional differences.

BACKGROUND/AIMS: To accurately quantify liver function using gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid (Gd-EOB-DTPA)-enhanced MR imaging. METHODOLOGY: A total of 105 patients with suspicion of a hepatic tumor (Child­Pugh scores: 5 in 56, 6 in 26, 7 in 20, and 8 in 3) who underwent Gd-EOB-DTPA-enhanced MR imaging and an indocyanine green retention rate at 15 min (ICG-R15) evaluation were retrospectively analyzed. The hepatobiliary images were taken at 20 min after Gd-EOB-DTPA injection. The quantitative liver­spleen contrast ratio (Q-LSC) was measured by calculating the signal intensity of the spleen and 12 intrahepatic points consisting of each central zone (near the porta hepatis) and peripheral zone (near the subcapsular zone) in the two main liver lobes. RESULTS: Each averaged Q-LSC of six points in the central zone or right lobe was significantly higher than that in the peripheral zone or left lobe regardless of hepatic function. The mean Q-LSC of the 12 points was significantly correlated with the ICG-R15 and significantly decreased with elevation of the Child­Pugh score. CONCLUSIONS: The hepatic enhancement by Gd-EOB-DTPA is influenced by zonal and lobar differences. This method with consideration of regional differences is valid for estimation of liver function by Gd-EOB-DTPA-enhanced MR imaging.

A Predictive Rule for COVID-19 Pneumonia Among COVID-19 Patients: A Classification and Regression Tree (CART) Analysis Model.

BACKGROUND: In this study, we aimed to identify predictive factors for coronavirus disease 2019 (COVID-19) patients with complicated pneumonia and determine which COVID-19 patients should undergo computed tomography (CT) using classification and regression tree (CART) analysis. METHODS: This retrospective cross-sectional survey was conducted at a university hospital. We recruited patients diagnosed with COVID-19 between January 1 and December 31, 2020. We extracted clinical information (e.g., vital signs, symptoms, laboratory results, and CT findings) from patient records. Factors potentially predicting COVID-19 pneumonia were analyzed using Student's t-test, the chi-square test, and a CART analysis model. RESULTS: Among 221 patients (119 men (53.8%); mean age, 54.59±18.61 years), 160 (72.4%) had pneumonia. The CART analysis revealed that patients were at high risk of pneumonia if they had C-reactive protein (CRP) levels of >1.60 mg/dL (incidence of pneumonia: 95.7%); CRP levels of ≤1.60 mg/dL + age >35.5 years + lactate dehydrogenase (LDH)>225.5 IU/L (incidence of pneumonia: 95.5%); and CRP levels of ≤1.60 mg/dL + age >35.5 years + LDH≤225.5 IU/L + hemoglobin ≤14.65 g/dL (incidence of pneumonia: 69.6%). The area of the curve of the receiver operating characteristic of the model was 0.860 (95% CI: 0.804-0.915), indicating sufficient explanatory power. CONCLUSIONS: The present results are useful for deciding whether to perform CT in COVID-19 patients. High-risk patients such as those mentioned above should undergo CT.

Late recurrence of a papillary thyroid carcinoma 37 years after hemithyroidectomy: Solitary, left cervical lymph node metastasis evident on fluorodeoxyglucose positron-emission tomography/computed tomography images revealing nodular uptake.

In patients with well-differentiated papillary thyroid carcinoma (PTC), late recurrence is very rare. It is unusual that 18F-fluorodeoxyglucose positron-emission tomography/computed tomography (PET/CT) shows hypermetabolic lesions in patients with well-differentiated PTC metastases. We demonstrate an exceptional case exhibiting a first relapse 37 years after hemithyroidectomy to treat PTC. Recurrent metastasis of a PTC should be considered as a differential diagnosis even if the elapsed time from the initial treatment is great. A left cervical lymphadenopathy, which exceptionally exhibited a hypermetabolic lesion on PET/CT, should be considered a metastatically well-differentiated PTC.

Development of MRI Projection Mapping System for Breast-Conserving Surgery in the Operating Room: Preliminary Clinical Results in Invasive Breast Cancer.

AIM: To evaluate the feasibility of a newly developed prototype MRI projection mapping (PM) system for localization of invasive breast cancer before breast-conserving surgery. METHODS: This prospective study enrolled 10 women with invasive breast cancer. MRI was performed in both prone and supine positions. The tumor location was drawn on the breast skin using palpation and sonography while referring to the prone MRI (i.e., a conventional method). A maximum intensity projection image generated from the supine MRI was projected using our PM system, and the tumor location was drawn. The PM system consisted of a projector and a camera and was used to measure the shape of the breast surface using the structured light method. Breast-conserving surgery was performed based on the conventional method. We compared the tumor size and location between the PM and conventional methods or pathology. RESULTS: There were no significant differences in the maximum diameters of invasive cancers between the PM system and the conventional method or pathology. The maximum discrepancy in tumor location between the PM and conventional method was 3-8 mm. CONCLUSIONS: This PM system may support breast-conserving surgery by showing the tumor size and location on the breast surface.

Endurance exercise increases the protein levels of PGC-1α and respiratory chain complexes in mouse skeletal muscle during atorvastatin administration.

Statins and exercise reduce cardiovascular disease incidence. We investigated whether endurance exercise in mice induces mitochondrial adaptation in skeletal muscle and muscle injury during administration of atorvastatin, a member of the statin medication class. Male C57BL mice were assigned to one of three groups: control (Con), statin (Statin), or statin and exercise (Statin + Ex). Atorvastatin was administered, and exercise performed on a treadmill for 8 weeks. The levels of mitochondria-associated proteins, PGC-1α, and respiratory chain complex, (COX) I-V, in the quadriceps femoris, and serum creatine kinase, a muscle injury marker, were measured. PGC-1α and COX I-V were upregulated in the Statin + Ex group compared to those in the Statin and Con groups; serum creatine kinase levels were similar. Endurance training in mice induced mitochondrial adaptation in skeletal muscle without causing muscle injury, during atorvastatin administration.

Three-dimensional high-resolution simultaneous quantitative mapping of the whole brain with 3D-QALAS: An accuracy and repeatability study.

BACKGROUND: Previous methods for the quantification of brain tissue properties by magnetic resonance imaging were mainly based on two-dimensional acquisitions and were thus limited to a relatively low resolution in the slice direction compared to three-dimensional (3D) acquisitions. The 3D-quantification using an interleaved Look-Locker acquisition sequence with a T2 preparation pulse (3D-QALAS) sequence may allow for simultaneous acquisition of relaxometry parameters in high spatial resolution. PURPOSE: To evaluate bias, linearity, and day-to-day repeatability of relaxometry parameters, as well as tissue fraction maps, acquired with 3D-QALAS. MATERIALS AND METHODS: Scan-rescan test of the 3D-QALAS sequence was performed on a 1.5-T scanner with the International Society for Magnetic Resonance in Medicine/National institute of Standards and Technology system phantom and 10 healthy volunteers (7 male, 3 female; mean age, 23.2 ±â€¯3.6 years). Simple linear regression analysis, Bland-Altman plots, and intrasubject coefficients of variation (CV) were used to assess the reliability of 3D-QALAS sequence-derived parameters. The T1, T2, proton density (PD), and myelin volume fraction (MVF) of in vivo brain regions were compared with values obtained using the multidynamic multi-echo sequence. RESULTS: In the phantom study, the T1, T2, and PD values measured by 3D-QALAS showed strong linearity with the reference values (R2 = 0.998, 0.998, and 0.960 for T1, T2, and PD, respectively) and high repeatability (mean CV of 1.2%, 2.8%, and 2.9% for T1, T2, and PD, respectively). The T1, T2, PD, and MVF values of in vivo brain regions obtained with 3D-QALAS were highly consistent within subjects, with mean intrasubject CVs of 0.5%, 0.5%, 0.4%, and 1.6% for the T1, T2, PD, and MVF values, respectively. CONCLUSION: 3D-QALAS enables reliable measurement of T1, T2, PD, and MVF values of the whole brain in high spatial resolution across a clinically-relevant dynamic range.

Quantitative MDCT analysis of pulmonary solid nodules using three parameters.

PURPOSE: The purpose of this prospective study was to perform quantitative multidetector computed tomography (MDCT) analysis of pulmonary solid nodules using three parameters (long-short ratio, compactness, and intranodular CT number) and to evaluate the usefulness of each parameter in the differentiation of the nodules. MATERIALS AND METHODS: Seventy solitary pulmonary nodules with a long axis length of 5-30 mm were examined using one multidetector CT (MDCT) system and one three-dimensional (3D) system, and the findings regarding the three parameters were statistically analyzed among five diseases (hamartoma, organizing pneumonia, adenocarcinoma, squamous cell carcinoma, and metastasis). RESULTS: The long-short ratio of the pulmonary nodule showed no significant differences among five diseases. The compactness showed significant differences (P < 0.05) in five pairs of diseases. Intranodular CT number showed significant differences (P < 0.05) in three pairs of diseases. CONCLUSION: Our results are insufficient for the complete differentiation of pulmonary solid nodules. However, among the three parameters, compactness and intranodular CT number contribute somewhat to the differentiation of pulmonary nodules.

A symptomatic child with ceftriaxone-associated biliary pseudolithiasis.

A 5-year-old boy who had pneumonia was treated in a neighboring hospital. Ceftriaxone was administrated 2 g/day divided into two equal intravenous doses. After 1 week of ceftriaxone therapy, the patient developed abdominal pain. In our hospital, an abdominal sonogram showed a hyperechoic band with postacoustic shadow within the collapsed gallbladder. He was diagnosed with ceftriaxone-associated biliary pseudolithiasis, and ceftriaxone therapy was ceased. On the 8th our hospital day, he again complained of right abdominal pain after supper. A sonogram revealed high-amplitude echoes within the gallbladder neck and common bile duct. Furthermore, bile duct dilatation was observed. He was managed conservatively, after which the symptoms were resolved. On the 11th day, a sonogram showed only sludge within the gallbladder, and on the 13th day, he was discharged from our hospital. It is important for sonographers to recognize the possible occurrence of biliary pseudolithiasis in ceftriaxone-treated patients, especially when a high dose is used in children.

Intracranial carotid calcification on CT images as an indicator of atheromatous plaque: analysis of high-resolution CTA images using a 64-multidetector scanner.

PURPOSE: Intracranial arterial wall calcifications are frequently observed on routine head computed tomography (CT) images. The purpose of this study was to evaluate whether calcification of the intracranial carotid artery on CT images could predict atheromatous plaque and luminal stenosis. MATERIALS AND METHODS: A total of 259 patients were examined using three-dimensional CT angiography using high-resolution 64 detector scanners. We examined patients from the petrous portion to the top of the internal carotid arteries. We evaluated the existence of calcification and atheromatous plaque based on our criteria retrospectively. The thickness of calcification was measured in each vessel, and the shape of calcification was classified into three types. RESULTS: There was low correlation between the thickness of the calcification and luminal stenosis, but the shape of the calcification corresponded well to the stenosis. The population of patients with >50% stenosis of the intracranial carotid artery differed statistically significantly for each calcification shape. There was a high negative predictive value (97.7%) in the correlation between the existence of calcification and atheromatous plaque on the multidetector CT images. CONCLUSION: Calcification of the intracranial carotid artery on CT images shows a high negative predictive value for the existence of atheromatous plaque in the same artery. The thickness of the calcification did not correlate well with luminal stenosis, but its shape seemed to predict luminal stenosis.

[A case of intracranial dural arteriovenous fistula presenting with brainstem infarction].

A 68-year-old female presented with the disturbance of brainstem function. Brain T2 weighted and FLAIR (fluid-attenuated inversion recovery) magnetic resonance imaging revealed the hyperintensity signal of the medulla oblongata, which led to diagnosis of brainstem infarction. Diagnostic cerebral angiography showed the dural arteriovenous fistula (DAVF) developed on the left transverse sinus (TS). Venous drainage route was consisted of retrograde leptomeningieal venous reflux of the cerebrum and spinal perimedullary vein via superior petrosal sinus. Venous hypertension of the brainstem was relieved by transvenous platinum coil selective embolization of superior petrosal sinus. The correct analysis of venous drainage pattern is essential for the curative endovascular surgery.

Two cases of primary small cell carcinoma of the breast showing non-mass-like pattern on diagnostic imaging and histopathology.

Primary small cell carcinoma of the breast is a rare breast cancer. We report two cases of this entity showing a non-mass-like pattern on multimodality images and histopathology. Both women presented with a breast mass, and one had axillary lymphadenopathy. Both cases revealed fine calcification on mammography (MMG) and an irregularly shaped, hypoechoic lesion on ultrasonography. Computed tomography (CT) and magnetic resonance imaging (MRI) showed non-mass-like enhancement in both cases. Dynamic MRI showed medium initial enhancement followed by persistent delayed enhancement in one patient, whereas rapid initial enhancement with plateau delayed enhancement was observed in the other. The breast lesions showed very high signal intensity on diffusion-weighted MRI. Positron emission tomography showed moderate accumulation of 2-fluoro-2-deoxyglucose in the breast tumor and lymph node metastasis. The non-mass-like enhancement on CT and MRI and the segmental fine calcification on MMG indicate the abundance of components of ductal carcinoma in situ and the breast origin of the small cell carcinoma.

Usefulness of 201Tl and 99mTc MIBI scintigraphy in a case of oncogenic osteomalacia.

A 45-year-old male was admitted with difficulty in walking due to leg pain. At the time of the first visit, a reduced serum phosphorus concentration and an increased serum alkaline phosphatase concentration of unknown etiology were observed. Either a whole body bone scintigraphy or CT of the neck, chest and abdominal region did not reveal any underlying disease. However both the whole body 201Tl scintigraphy and 99mTc MIBI SPECT showed accumulation in the right knee region, and a small tumor was detected by MRI examination. After a diagnosis of oncogenic osteomalacia due to this tumor was determined the tumor was surgically removed, and turned out to be a hemangiopericytoma. By removal of the tumor, either the symptoms or the laboratory data were improved significantly. In this case, both 201Tl scintigraphy and 99mTc scintigraphy MIBI were useful in identifying the location of the tumor which caused oncogenic osteomalacia.

Thallium-201 accumulation in a patient with brain abscess.

A 57-year-old man was admitted to our hospital because of high fever and generalized tonic seizure. Brain magnetic resonance imaging (MRI) delineated multiple abnormal intensity areas. Thallium-201 (201Tl) scintigraphy revealed abnormal uptake in the brain. The imaging findings did not allow definitive exclusion of brain tumor, even though brain abscess was the more strongly suspected diagnosis. As the patient improved, the multiple abnormal intensity areas in the brain on MRI and the abnormal areas of accumulation on 201Tl scintigraphy were reduced, and eventually completely disappeared. A final diagnosis of brain abscess was therefore made. Since relatively few studies have reported 201Tl accumulation in cases of brain abscess, we report here our patient in whom the changes in the accumulation of 201Tl in a brain abscess were observed over time.

Focal sparing of segment 2 in fatty liver: US appearance.

PURPOSE: To determine the frequency and sonographic features of focal sparing of fatty liver at segment 2. MATERIALS AND METHODS: The sonographic database was searched over the preceding three years. The criteria for sonographic diagnosis of focal sparing of fatty liver was an area of liver parenchyma of relatively low echogenicity with lack of mass effect. RESULTS: Six (0.9%) of 686 patients with diffuse fatty liver showed focal sparing at segment 2. The areas showed spherical or ovoid hypoechoic mass-like lesions measuring 2 to 6 cm in longest diameter (average, 3.8 cm). These all abutted on the posterior surface of segment 2 adjacent to the ligamentum venosum. These were segmental in two cases and subsegmental in four. CONCLUSION: In diffuse fatty liver, segment 2 is infrequently spared, and this may be a helpful adjunct sign of fatty liver.

Distribution of estimated glomerular filtration rate (eGFR) values in patients receiving contrast-enhanced magnetic resonance imaging.

PURPOSE: The aim of this study was to elucidate the distribution of estimated glomerular filtration rate (eGFR) values in patients who underwent gadolinium-based contrast agent (GBCA)-enhanced magnetic resonance imaging (MRI) at different types of hospitals. MATERIALS AND METHODS: We retrospectively studied 2,550 patients who underwent MRI at five institutions. We recorded the date and value of each patient's eGFR test. The distribution of eGFR values was compared with that in the general Japanese population. RESULTS: A total of 84.3% of patients had their eGFRs evaluated before GBCA-enhanced MRI. Of these, 84.7% were evaluated within 3 months before the GBCA-enhanced MRI, and 1.3% were evaluated on the day of the GBCA-enhanced MRI. A total of 87.2% of patients tested had an eGFR of ≥60 ml/min/1.73 m(2); 12.8% had an eGFR of <60 and ≥30 ml/min/1.73 m(2), and no patients had an eGFR of <30 ml/min/1.73 m(2). CONCLUSION: The rate of renal function evaluation differed among hospitals. The prevalence of low eGFR values was greater in Juntendo Tokyo Koto Geriatric Medical Center than in the other hospitals, and the prevalence of low eGFR values was greater in patients who underwent GBCA-enhanced MRI than in the general Japanese population.

Evaluation of effective dose during abdominal three-dimensional imaging for three flat-panel-detector angiography systems.

The purpose of this study was to evaluate the effective dose during abdominal three-dimensional (3D) imaging on phantoms and estimate the dose-area product (DAP) for effective dose conversion factors for three types of angiographic units. Three-dimensional imaging was performed for three sizes (small, medium, large) of human-shaped phantoms using three types of angiographic units (Allura Xper FD20/10, INNOVA 4100, AXIOM Artis dTA). We calculated 25 organ doses and effective doses using Monte Carlo technique for the three phantoms with a program for a personal computer. As benchmark studies to back up the results by Monte Carlo technique, we measured the organ doses directly on the small phantom using radiophotoluminescent glass dosimeters. The DAP value increased as the phantom size increased. The organ doses and the effective doses during the 3D imaging increased as the phantom size increased. The effective doses for the small phantom by Monte Carlo technique were 1.9, 2.2, and 2.1 mSv for the Allura Xper FD20/10, INNOVA 4100, and AXIOM Artis dTA, respectively, while those by direct measurement were 1.6, 2.0, and 2.6 mSv. The effective doses to DAP ratios by Monte Carlo technique were 0.37-0.45, 0.26-0.32, and 0.13-0.15 (mSv Gy⁻¹ cm⁻²) for the Allura Xper FD20/10, INNOVA 4100, and AXIOM Artis dTA, respectively. In conclusion, the effective doses during 3D imaging and the dose-to-DAP ratios differ among angiographic units, and the effective dose can be estimated using a proper conversion factor for each angiographic unit.

Retropharyngeal neuroblastoma in a neonate: case report and literature review.

Primary cervical neuroblastoma (NB) in neonates is extremely rare. We treated a 1-day-old male neonate who presented with stridor and feeding difficulty and was subsequently diagnosed with NB of the retropharynx. The tumor was excised in toto transorally, and no metastatic lesions were confirmed. Histopathology and molecular genetic analysis showed poorly differentiated NB with no N-myc amplification, stage I NB. He has had no signs of recurrence or adverse sequelae during 18 months of follow-up. We report our experience and review the literature.