Steatohepatitic hepatocellular carcinoma: imaging findings with clinicopathological correlation.

AIM: To evaluate the clinicopathological and computed tomography (CT) and magnetic resonance imaging (MRI) findings of steatohepatitic hepatocellular carcinoma (SH-HCC). MATERIALS AND METHODS: Clinicopathological and radiological features were evaluated in 20 patients with SH-HCC. The diagnosis of SH-HCC was made histologically if the tumour had four of the following five characteristics: steatosis (>5% tumour cells), ballooning, Mallory-Denk bodies, interstitial fibrosis, and inflammation. All patients underwent dynamic CT and MRI. CT and MRI images were reviewed for morphological features including tumour size, presence, and distribution of fat, and patterns and degree of contrast enhancement. RESULTS: Obesity, hypertension, and history of heavy alcohol intake were common clinical findings observed in 10 (50%), 13 (65%), and 11 (55%) of the 20 patients, respectively. Steatosis and steatohepatitis were pronounced in the background liver in 12 (60%) and 10 (50%) patients, respectively. SH-HCC was moderately differentiated in 18 patients (90%) and well differentiated in two (10%). Pathologically, steatohepatitic features were diffuse in 12 (60%) of the 20 tumours and focal in eight (40%). Tumour size and the percentage of intratumoural steatosis were not correlated (r=0.17, p=0.47). On CT, 16 (80%) patients showed arterial phase enhancement and delayed washout. On MRI, 16 (80%) of 20 tumours showed prominent fatty deposition (10 diffusely, six focally) with arterial phase enhancement. CONCLUSIONS: SH-HCC is likely to show prominent fatty deposits with arterial phase enhancement on CT and MRI. A hypervascular lesion with prominent fatty change should raise the diagnostic suspicion of SH-HCC.

Impact of the COVID-19 pandemic on the incidence of surgical site infection after orthopaedic surgery: an interrupted time series analysis of the nationwide surveillance database in Japan.

BACKGROUND: During the COVID-19 pandemic, hygiene awareness was increased in communities and hospitals. However, there is controversy regarding whether such circumstances affected the incidence of surgical site infections (SSIs) in the orthopaedic surgical field. AIM: To examine the impact of the COVID-19 pandemic on the incidence of SSIs after orthopaedic surgery. METHODS: The medical records of patients having undergone orthopaedic surgery were extracted from the nationwide surveillance database in Japan. The primary outcomes were the monthly incidences of total SSIs, deep or organ/space SSIs, and SSIs due to meticillin-resistant Staphylococcus aureus (MRSA). Interrupted time series analysis was conducted between pre-pandemic (January 2017 to March 2020) and pandemic (April 2020 to June 2021) periods. RESULTS: A total of 309,341 operations were included. Interrupted time series analysis adjusted for seasonality showed no significant changes in the incidence of total SSIs (rate ratio 0.94 and 95% confidence interval 0.98-1.02), deep or organ/space SSIs (0.91, 0.72-1.15), or SSIs due to MRSA (1.07, 0.68-1.68) along with no remarkable slope changes in any parameter (1.00, 0.98-1.02; 1.00, 0.97-1.02; and 0.98, 0.93-1.03, respectively). CONCLUSIONS: Awareness and measures against the COVID-19 pandemic did not markedly influence the incidence of total SSIs, deep or organ/space SSIs, or SSIs due to MRSA following orthopaedic surgery in Japan.

Spermatogenic function in cats.

There are limited data on feline sperm production. We exhausted epididymal spermatozoa (i.e. the number of ejaculated spermatozoa <5 × 10(6)) by frequent semen collections using the artificial vagina method in five tomcats and determined the number of spermatozoa stored in the epididymis. We investigated the time (days) required for the number of epididymal spermatozoa to return to the pre-exhaustion level and determined the number of spermatozoa produced per day. After spermatozoa were exhausted by frequent semen collection, 6 or more days were required to return to the pre-exhaustion level. Based on the duration of resting (days) and total number of spermatozoa, the mean number of spermatozoa produced per day was 30 × 10(6).

Plasma hormone levels and semen quality in male cats during non-breeding and breeding seasons.

Female cats are known to be seasonal breeders and male cats annual breeders. Despite this, there are limited data on the influence of breeding season (BS) on hormone concentration and semen quality in the male cat. This study compared plasma concentrations of LH and testosterone (T), and semen quality during the non-breeding season (NBS) and BS in five male cats subject to natural hours of daylight but a constant environmental temperature. Plasma LH and T concentrations were higher during the BS in 2/35 and 3/5 cats, respectively, although when comparing both hormones combined, values were higher during the BS than the NBS in all cats (p < 0.01). There were no significant differences in the percentage of abnormal sperm between the cats. Overall, semen quality was superior during the BS with larger semen volume in 2/5, sperm motility in 2/5 and sperm viability in 3/5 cats. Although there was a clear seasonal effect on hormone secretion and semen quality, during the NBS all cats were likely to have been fertile.

Plasma LH, ovulation and conception rates in cats mated once or three times on different days of oestrus.

Although cats are induced ovulators, the relationship between the day of breeding, the number of matings and the likelihood of ovulation and conception have not been extensively investigated. In this experiment, cats were mated either once or three times on day 1 or day 5 of oestrus to study the incidence of the LH surge, ovulation and conception rates. The percentage ovulating and the conception rates after a single mating on day 1 of oestrus were 60% (6/10) and 33.3% (2/6), respectively, and for cats mated once on day 5 of oestrus were 83.3% (10/12) and 40% (4/10), respectively. When cats were mated three times on day 1 of oestrus, the ovulation rates and conception rates were 70% (7/10) and 85.7% (6/7), respectively, and for those mated three times on day 5 of oestrus were 100% (10/10) and 100% (10/10), respectively. The concentration of LH did not increase in non-ovulating cats, and cats that were mated three times had LH concentrations that were numerically higher than those that were mated once. Litter size was neither related to the day of mating nor to the number of matings. Although an increase in the number of matings on day 1 of oestrus produced a numerically larger LH surge, it did not increase the ovulation rate, suggesting that plasma oestradiol concentrations were not sufficiently elevated to induce a high pituitary response to mating stimulation. The conception rate after a single mating was low, suggesting that the number of sperm per mating was not sufficient. These results suggest that mating more than once in the middle of oestrus is required to improve ovulation rates and conception rates in cats.

The role of the ovary for the maintenance of pregnancy in cats.

Plasma progesterone (P(4)) concentrations are maintained in pregnant cats until parturition, but become low in pseudopregnant cats 40-45 days after infertile mating. This difference in P(4) concentrations is considered to be due to P(4) secretion by the placenta of pregnant cats. Therefore, to clarify these points, we performed ovariectomy (OVX) at various stages of pregnancy, examined the pregnancy status and measured LH and P(4) concentrations in peripheral, ovarian and uterine venous blood. After OVX, abortion occurred in 100% (5/5), 80% (4/5), 40% (2/5) and 60% (3/5) of Groups I (Day 35), II (Day 40), III (Day 45) and IV (Day 50) cats, respectively. In the remaining cats, normal delivery took place on days 63-69 [mean, 66.1 +/- 1.1 (SE)] of pregnancy. The time to abortion after OVX was 4-8 (mean, 5.6 +/- 0.8), 3-17 (mean, 8.0 +/- 3.6), 10 and 11, and 2-4 (mean, 3.0 +/- 0.7) days in Groups I, II, III and IV, respectively. The plasma P(4) concentrations were 1-2 ng/ml in all groups on the day after OVX, decreasing to less than 1 ng/ml from the 2nd day onwards. The concentrations of P(4) in ovarian venous blood at the time of OVX decreased with the stage of pregnancy, but were clearly higher than those in peripheral blood. The plasma P(4) concentrations in uterine venous blood were similar to those in peripheral blood. These results suggest that peripheral P(4) in pregnant cats is the result of P(4) secretion secreted only by the ovarian corpus luteum, not by the placenta, but indicate that either P(4) is not essential for the maintenance of pregnancy in cats from day 40-45 of pregnancy onwards, or that the placenta provides a local source of P(4) that does not appear in measurable amounts in the peripheral circulation.

Imaging Differences between Neuromyelitis Optica Spectrum Disorders and Multiple Sclerosis: A Multi-Institutional Study in Japan.

BACKGROUND AND PURPOSE: Both clinical and imaging criteria must be met to diagnose neuromyelitis optica spectrum disorders and multiple sclerosis. However, neuromyelitis optica spectrum disorders are often misdiagnosed as MS because of an overlap in MR imaging features. The purpose of this study was to confirm imaging differences between neuromyelitis optica spectrum disorders and MS with visually detailed quantitative analyses of large-sample data. MATERIALS AND METHODS: We retrospectively examined 89 consecutive patients with neuromyelitis optica spectrum disorders (median age, 51 years; range, 16-85 years; females, 77; aquaporin 4 immunoglobulin G-positive, 93%) and 89 with MS (median age, 36 years; range, 18-67 years; females, 68; relapsing-remitting MS, 89%; primary-progressive MS, 7%; secondary-progressive MS, 2%) from 9 institutions across Japan (April 2008 to December 2012). Two neuroradiologists visually evaluated the number, location, and size of all lesions using the Mann-Whitney U test or the Fisher exact test. RESULTS: We enrolled 79 patients with neuromyelitis optica spectrum disorders and 87 with MS for brain analysis, 57 with neuromyelitis optica spectrum disorders and 55 with MS for spinal cord analysis, and 42 with neuromyelitis optica spectrum disorders and 14 with MS for optic nerve analysis. We identified 911 brain lesions in neuromyelitis optica spectrum disorders, 1659 brain lesions in MS, 86 spinal cord lesions in neuromyelitis optica spectrum disorders, and 102 spinal cord lesions in MS. The frequencies of periventricular white matter and deep white matter lesions were 17% and 68% in neuromyelitis optica spectrum disorders versus 41% and 42% in MS, respectively (location of brain lesions, P < .001). We found a significant difference in the distribution of spinal cord lesions between these 2 diseases (P = .024): More thoracic lesions than cervical lesions were present in neuromyelitis optica spectrum disorders (cervical versus thoracic, 29% versus 71%), whereas they were equally distributed in MS (46% versus 54%). Furthermore, thoracic lesions were significantly longer than cervical lesions in neuromyelitis optica spectrum disorders (P = .001), but not in MS (P = .80). CONCLUSIONS: Visually detailed quantitative analyses confirmed imaging differences, especially in brain and spinal cord lesions, between neuromyelitis optica spectrum disorders and MS. These observations may have clinical implications.

Hemimegalencephaly: a study of abnormalities occurring outside the involved hemisphere.

BACKGROUND AND PURPOSE: Hemimegalencephaly is a rare but well-known congenital malformation with ipsilateral enlargement of the hemicerebrum. However, very little is known about changes in structures outside the involved hemisphere in patients with this condition. We investigated morphologic abnormalities occurring outside the affected hemisphere by MR imaging in a large series of patients with hemimegalencephaly. MATERIALS AND METHODS: MR imaging findings for 30 patients with hemimegalencephaly were retrospectively reviewed and evaluated for structures outside the involved hemisphere on routine MR images, such as cranial nerves (I, II, V), brain vessels, subdural and subarachnoid spaces, brain stem, and cerebellum, on both the ipsilateral and contralateral sides. RESULTS: The ipsilateral olfactory and optic nerves were enlarged in 8 (26.7%) and 1 (3.3%) of the 30 patients, respectively, without enlargement on the contralateral side. No asymmetry was noted in the trigeminal nerves. Asymmetric vascular dilations in the ipsilateral cerebral hemisphere were observed in 12 of the 30 patients (40%), in deep cerebral vessels in 11 patients (36.7%), and in superficial cerebral vessels in 8 patients (26.7%). Ipsilateral brain stem and hemicerebellar asymmetric enlargement was detected in 2 patients (6.7%) and 14 patients (46.7%), respectively. Abnormal cerebellar folia were observed on the ipsilateral side in 6 patients (20%) and on the contralateral side in 3 patients (10%). CONCLUSION: Ipsilateral olfactory nerve enlargement, cerebral vascular dilations, cerebellar enlargement, and bilateral or ipsilateral abnormal architecture of the cerebellar folia are often associated with hemimegalencephaly.

Reversible splenial lesion with restricted diffusion in a wide spectrum of diseases and conditions.

OBJECTIVE: Reversible lesion in the central area of the splenium of the corpus callosum (SCC) is a unique phenomenon occurring particularly in patients with encephalitis or encephalopathy and in patients receiving antiepileptic drugs (AED). We report MR imaging findings, clinical courses, and outcomes in eight patients with various diseases and conditions. MATERIALS AND METHODS: Eight patients with a reversible SCC lesion with transiently restricted diffusion were reviewed retrospectively. Diseases and conditions that were associated with a reversible lesion included epilepsy receiving AED (n=1), seizure from eclampsia receiving AED (n=1), mild infectious encephalitis (n=2), hypernatremia resulting in osmotic myelinolysis (n=1), and neoplasm (n=3) such as acute lymphocytic leukemia, spinal meningeal melanocytoma, and esophageal cancer. We evaluated MR imaging findings and clinical findings. RESULTS: Seven patients had isolated SCC lesions; one patient with osmotic myelinolysis showed additional parenchymal lesions. The reversible SCC lesion shape was oval (n=6) or extended (n=2). The mean apparent diffusion coefficient value of the splenial lesion was 0.40+/-0.16 x 10-3 mm2/s, ranging from 0.22 to 0.64 x 10-3 mm2/s. In a patient with osmotic myelinolysis, additional white matter lesions, shown as restricted diffusion, were revealed as not reversible on follow-up MR imaging. Neurological courses and outcomes were good in seven patients with isolated SCC lesions, but poor in one with osmotic myelinolysis. CONCLUSION: Reversible SCC lesion with restricted diffusion is apparent in a wide spectrum of diseases and conditions. Neurological courses and outcomes are good, particularly in patients with isolated SCC lesions. Knowledge of MR imaging findings and the associated spectrum of diseases and conditions might prevent unnecessary invasive examinations and treatments.

Determination of flow and rate constants in a kinetic model of [99mTc]-hexamethyl-propylene amine oxime in the human brain.

The values for flow and rate constants for a kinetic model of [99mTc]-hexamethylpropyleneamine oxime (HM-PAO) distribution in the human brain were determined. The single-pass extraction ratio of HM-PAO was also determined in the rat brain by the indicator diffusion method; a value of 0.90 +/- 0.02 (mean +/- SEM, n = 5) was obtained. Time course data of brain activity and arterial blood activity of the tracer were fitted to a four compartment model: Values of blood flow and the first-order rate constants for backdiffusion of the diffusible tracer from brain to blood (k2), conversion of the lipophilic tracer to the hydrophilic one in brain (k3), and conversion of the diffusible tracer to the nondiffusible one in blood (k5) were determined. Conversion of hydrophilic tracer back to a lipophilic form in both blood and brain was assumed to be negligible during the course of the experiment. The values obtained for blood flow, k2, and k3 were, respectively, 0.40 +/- 0.03 ml/g/min, 0.38 +/- 0.04 min-1, and 0.92 +/- 0.05 min-1 in the gray matter (n = 4), and 0.23 +/- 0.01 ml/g/min, 0.17 +/- 0.01 min-1, and 1.01 +/- 0.05 min-1 in the white matter (n = 2) in patients with cerebrovascular disorder. The k5 value was 1.14 +/- 0.06 min-1 (n = 4). These experimentally determined values agree well with the theoretical ones previously reported by Lassen et al. The results suggest the relative constancy of the k3 and k5 values and the more prominent initial backdiffusion of the lipophilic HM-PAO from brain to blood in high flow regions compared to low flow regions.

Evaluation of cerebral collateral circulation by technetium-99m HM-PAO brain SPECT during Matas test: report of three cases.

Three cases with cerebral ischemic symptoms and an intracranial aneurysm are presented. Using [99mTc]hexamethyl-propyleneamine oxime (HM-PAO) single photon emission computed tomography imaging before and during the Matas test, a quantitative measurement method was developed for evaluating brain collateral circulation. The evaluation correlated well with findings of contrast carotid angiography. This noninvasive method seems to be useful for selection of patients for appropriate surgical treatment.

Autoradiographic analysis of iodoamphetamine redistribution in experimental brain ischemia.

The pathophysiologic significance of iodoamphetamine (IMP) redistribution was analyzed using a double radionuclide autoradiography technique in experimental brain ischemia in the rat. Within 4 hr after unilateral arterial occlusion, IMP almost completely redistributed at 150 min postinjection in the affected areas. At 2 min postinjection, both a remarkable decrease of IMP accumulation and histopathologic change of diminished staining were observed in these areas. The redistribution amplitude was higher in the affected hemisphere, especially in the regions surrounding the ischemic core than in the unaffected hemisphere. These findings were consistent with computer simulation studies of the time course of brain activity based on the standard diffusible tracer model. The results suggest that IMP redistribution in the ischemic area is due to differences of the temporal changes of the brain activity between the unaffected and affected areas and that it is a "physical" phenomenon (only flow related) rather than a "biologic" one.

Holoprosencephaly: an analysis of callosal formation and its relation to development of the interhemispheric fissure.

PURPOSE: To correlate the degree of hemispheric fusion in holoprosencephaly with degree of callosal formation, with degree of thalamic and basal ganglia fusion, and with presence or absence of dorsal cyst. METHODS: MR, CT, and ultrasonography from 19 patients with holoprosencephaly was retrospectively reviewed. The imaging studies were graded according to extent of the hemispheric fusion, thalamic fusion, corpus striatum fusion, callosal formation, and the presence or absence of a dorsal cyst. These factors were statistically correlated with each other using Kendall rank correlation coefficient. RESULTS: There were significant correlations between hemispheric fusion and failure of corpus callosum formation, presence of dorsal cyst and failure of corpus callosum formation, and hemispheric fusion and presence of dorsal cyst. Additional correlations were noted between thalamic fusion and corpus striatum fusion. CONCLUSIONS: Our results suggest that the presence of an interhemispheric fissure is necessary for callosal formation, and the presence of a dorsal cyst may interfere with callosal formation in holoprosencephaly.

Direct autoradiographic comparison of 99Tcm-HMPAO with 125I-IMP in experimental brain ischaemia.

Local cerebral blood flow (LCBF) images of HMPAO and IMP were directly compared in experimental brain ischaemia in the same rats using a double-tracer autoradiographic technique. Both images were identical in distribution throughout the whole flow areas. However, LCBF values were much lower in HMPAO than in IMP. The results suggest that HMPAO acts as a chemical microembolus in rat brain in both low and high flow areas; however, a quantitative flow measurement is difficult in an HMPAO study.

Influence of angiotensin-converting enzyme gene polymorphism on development of athlete's heart.

BACKGROUND AND HYPOTHESIS: Genetic influence on development of athlete's heart is uncertain. This study investigated whether angiotensin-converting enzyme (ACE) gene polymorphism influenced development of athlete's heart. METHODS: Forty-three participants in a 100-km ultramarathon were classified on the basis of ACE gene polymorphism into a deletion group (n = 26) and an insertion group (n = 17). Echocardiograms were recorded to determine left ventricular end-diastolic and end-systolic diameters, interventricular septal thickness, left ventricular posterior wall thickness, left ventricular mass, and ejection fraction. RESULTS: Left ventricular end-diastolic diameter (65.5 +/- 4.0 mm) and left ventricular mass (369.5 +/- 73.9 g) were significantly larger in the subjects with deletion than in those with insertion (57.4 +/- 4.2 mm, 306.5 +/- 93.7 g). However, no significant differences in the other parameters were noted. CONCLUSIONS: In long-distance runners, ACE gene polymorphism of the D/D and D/I genotypes has a stronger influence on left ventricular hypertrophy than polymorphism of the I/I genotype.

Dramatic intestinal uptake of 99mTc pertechnetate in a pediatric patient with enteritis.

A pediatric patient with enteritis, which showed dramatically diffuse uptake of 99mTc pertechnetate in the intestine, is reported. Repeated study after medical treatment exhibited complete disappearance of the intestinal uptake. 99mTc pertechnetate scintigraphy has the potentiality for diagnosing and monitoring active enteritis.

Visualization of the bone/bone marrow of lower extremities in Ga-67 whole-body images.

Patients whose Ga-67 whole-body images showed increased uptake by the bone/bone marrow of the lower extremities were selected and classified into three types according to the extent and the grade of the visualization. These types were then compared with their serum iron levels, iron-binding capacities, and the results of several other serum biochemical tests. Of 374 consecutive whole body 72-hr images reviewed, 59 (15.8%) showed increased uptake of the tracer by the bone/bone marrow of the lower extremities. The three classified types were as follows: type T--visualization of both tibiae and femurs; type S--strong visualization of the femurs; and type W--weak visualization of the femurs. The serum iron concentration was significantly high in type T and low in type S. In conclusion, the pattern of Ga-67 uptake by the bone/bone marrow of the lower extremities fairly closely reflects the status of iron metabolism.

Quantitative assessment of cerebral blood flow using technetium-99m-hexamethyl-propyleneamine oxime: Part I, Design of a mathematical model.

To design a mathematical model for quantifying cerebral blood flow using 99mTc-hexamethyl-propyleneamine oxime (HM-PAO), basic studies were performed in animals and human volunteers. Microautoradiography revealed that HM-PAO crossed the blood-brain barrier. Thin layer chromatographic studies demonstrated the rapid disappearance of free HM-PAO in the brain tissue. Back diffusion from brain to blood was found negligible. From these observations, the familiar microsphere model was employed in the measurements of blood flow with HM-PAO. This, however, resulted in much lower flow values than simultaneously obtained values with the labeled microspheres. This underestimation was ascribed to the high affinity of HM-PAO to blood cells and serum protein. Taking the binding of HM-PAO to blood components into consideration, the following model equation was designed for quantifying cerebral blood flow: Ce(t) = Ca(t)-kCa(t)*exp(-kt), Cb(T) = F integral of T0 Ce(t)dt, where Ce and Ca are the free HM-PAO concentration in the intravascular space and the arterial whole-blood concentration of HM-PAO, respectively, as a function of time (t), Cb is the brain activity concentration, k is the rate constant for the binding of HM-PAO to the blood components, F is the blood flow value, T is time of measurement, and * denotes the operation of convolution. In clinical studies, Ca(t) and Cb(T) are obtainable from a dynamic single photon emission computerized tomographic study of the brain and multiple arterial blood sampling, respectively. The values for F and k can be estimated using a nonlinear least squares fitting method.

Application of lipid microsphere drug delivery system to steroidal ophthalmic preparation.

The applicability of a lipid microsphere drug delivery system to ophthalmic preparations was examined using a lipid microsphere containing hydrocortisone 17-butyrate 21-propionate (HBP). 3H-labelled HBP ophthalmic suspension and 3H-labelled HBP lipid microsphere were applied to rabbit eyes, and the eyes were enucleated after 1 and 3 hours to determine 3H-labelled HBP levels in the ocular tissues. The lipid microsphere proved to deliver the drug to the anterior ocular tissues more significantly than the ophthalmic suspension. It is suggested that the lipid microsphere ophthalmic preparation of various lipophilic drugs including steroids may be useful as one of the drug delivery systems for ophthalmic therapy.

Decreased signal intensity of cerebral cortex on T2-weighted MR images.

To define the frequency of decreased signal intensity (DSI) in cerebral cortex on T2-weighted images relative to aging and to the incidence of identifying white matter pathology, T2-weighted MR brain images of 906 patients consecutively examined between July 1989 and June 1991 were reviewed. MR images of cerebral cortex were divided into five areas: frontal lobe (F), pre- and postcentral gyri (C), parietal lobe (P), occipital lobe (O) and temporal lobe (T). Each area was separately and independently evaluated for the presence or absence of DSI. The frequency of DSI in each area was plotted against patients' ages. The severity of leukoaraiosis was evaluated in relation with DSI in each cortical area. Patients with DSI in area F numbered 61 (5.7%), in area C 236 (26.0%), in area P 174 (15.9%), in area O 428 (47.2%), and in area T 10 (1.1%). The number of patients with DSI in each area increased with age. The greater the severity of leukoaraiosis, the greater the chance of finding DSI of the cerebral cortex. The incidence of DSI in the cerebral cortex increased with the patient's age as well as with the severity of co-existent white matter pathology.