Persistent primitive olfactory artery (PPOA) is a relatively rare variation of the proximal anterior cerebral artery (ACA). Traditionally, there are two types: Type 1 is a common type, which ...generally follows an anteroinferior course and which takes a hairpin turn before continuing to the A2 segment of the ACA. Type 2 is an extremely rare variation that continues to the anterior ethmoidal artery without a hairpin turn. Since Type 2 PPOAs are small in caliber, previously reported cases were found during anatomical dissection or were detected by catheter angiography. We herein report a case of Type 2 PPOA that was diagnosed by partial-maximum-intensity projection images of magnetic resonance angiography. This patient also had bilateral ophthalmic arteries arising from the middle meningeal artery. These two variations may be related to each other.
Purpose
To generate a new discrimination method to distinguish between malignant mesenchymal tumors of the uterus and T2-weighted hyperintense leiomyoma based on magnetic resonance imaging findings ...and clinical features.
Materials and methods
Data from 32 tumors of 32 patients with malignant mesenchymal tumors of the uterus and from 34 tumors of 30 patients with T2-weighted hyperintense leiomyoma were analyzed. Clinical parameters, qualitative magnetic resonance imaging features, including computed diffusion-weighted imaging, and quantitative characteristics of magnetic resonance imaging of these two tumor types were compared. Predictive values for malignant mesenchymal tumors of the uterus were calculated using variant discriminant analysis.
Results
The T1 bright area on qualitative assessment and mean apparent diffusion coefficient value on quantitative assessment yielded the most independent magnetic resonance imaging differentiators of malignant mesenchymal tumors of the uterus and T2-weighted hyperintense leiomyoma. The classification accuracy of the variant discriminant analysis based on three selected findings, i.e., a T1 bright area, computed diffusion-weighted imaging with a b-value of 2000s/mm
2
(cDWI
2000
), and T2-hypointense bands, was 84.8% (56/66), indicating high accuracy.
Conclusions
Variant discriminant analysis using the T1 bright area, cDWI
2000
, and T2-hypointense bands yielded high accuracy for differentiating between malignant mesenchymal tumors of the uterus and T2-weighted hyperintense leiomyoma.
To compare remission status at completion of chemotherapy for multiple myeloma (MM) with changes in total diffusion volume (tDV) calculated from whole-body diffusion-weighted imaging (WB-DWI) and fat ...fraction (FF) of lumbar bone marrow (BM) by modified Dixon Quant (mDixon Quant) soon after induction of chemotherapy, and to assess the predictive value of MRI.
Fifty patients (mean age, 66.9 ± 10.5 years) with symptomatic myeloma were examined before and after two cycles of chemotherapy. From WB-DWI data, tDV was obtained with the threshold for positive BM involvement. Mean FF was calculated from lumbar BM using the mDixon Quant sequence. At the completion of chemotherapy, patients were categorized into a CR/very good PR (VGPR) group (n = 15; mean age, 67.6 ± 10.3 years) and a PR, SD or PD group (n = 35; mean age, 69.1 ± 8.6 years). ROC curves were plotted to assess performance in predicting achievement of CR/VGPR.
At second examination, serum M protein, β2-microglobulin, and tDV were significantly decreased and hemoglobin, mean ADC, and FF were significantly increased in the CR/VGPR group and serum M protein was significantly increased in the PR/SD/PD group. The general linear model demonstrated that percentage changes in FF and M protein contributed significantly to achieving CR/VGPR (P = 0.02, P = 0.04, respectively). AUCs of ROC curves were 0.964 for FF and 0.847 for M protein.
Early change in FF of lumbar BM and serum M protein soon after induction of chemotherapy contributed significantly to prediction of CR/VGPR.
Purpose
To describe an extremely rare case of an aberrant course of the petrous internal carotid artery (ICA) associated with an ipsilateral type 1 proatlantal artery (PA) that was diagnosed by ...cerebral magnetic resonance (MR) angiography.
Case report
The patient was a 64-year-old man with double vision. Cerebral MR imaging and MR angiography were subsequently performed using a 1.5-T scanner. MR angiography showed an aberrant course of the petrous right ICA that was associated with right type 1 PA. The left vertebral artery (VA) and proximal right VA were absent.
Discussion
An aberrant course of the petrous ICA is rare but clinically significant, because it is dangerous during middle ear surgery. Type 1 PA is an extremely rare type of persistent fetal anastomosis between the carotid and vertebrobasilar systems. Type 1 PA is also clinically significant, because it is dangerous during craniovertebral junction surgery. We found no similar cases in the relevant English-language literature.
Conclusion
Although both variations were seen ipsilaterally and were located relatively close to each other, the embryological development of these variations is quite different. In addition, no similar case has been reported previously. Thus, these may have formed incidentally.
Diffusion-weighted (DW) imaging is a magnetic resonance (MR) imaging method. It is an indispensable sequence for the diagnosis of acute cerebral infarction and is recognized as a standard tool in ...oncologic imaging. Computed DW imaging refers to the synthesizing of arbitrary b-value DW images from a set of measured b-value images by voxelwise fitting. Computed DW imaging is advantageous because it generates DW images with a higher diffusion effect than that achievable by using the MR imaging units in use today. Additionally, computed DW imaging can reduce imaging time while producing images characterized by a higher signal-to-noise ratio than what the acquired DW images would display at the corresponding b values. By fitting input images acquired at a lower b value and correspondingly a shorter echo time, the signal intensity of the resulting computed DW image is closer to the ideal case. Computed DW images are generated by employing mathematical models that use mono-, bi-, or triexponential equations. To generate accurate computed DW images, the appropriate model must be selected, and the image parameters for the input data must be chosen accordingly. In addition, to reduce artifacts on computed DW images, the misalignment of input data must be corrected with the aid of image registration techniques.
RSNA, 2018.
Background
Although balloon-occluded retrograde transvenous obliteration (BRTO) is often selected to treat gastric varices caused by portal hypertension, data comparing BRTO and splenectomy with ...gastric devascularization (Sp + Dev) are limited.
Methods
From January 2009 to February 2018, 100 patients with gastric varices caused by portal hypertension who underwent Sp + Dev (
n
= 45) or BRTO (
n
= 55) were included. Overall survival (OS) and the rebleeding rate were calculated using the inverse probability of a treatment weighting-adjusted log-rank test. Independent risk factors were identified by Cox regression analysis. Changes in liver function and adverse events after the procedures were analyzed.
Results
Patients in the Sp + Dev group tended to have lower platelet counts than those in the BRTO group, but liver function did not differ between these groups. The 5-year OS rates for the Sp + Dev and BRTO groups were 73.4 and 50.0% (
p
= 0.005), respectively. There were no significant differences in rebleeding rates between the two groups. Multivariate analysis showed that serum albumin level ≤3.6 g/dL, prothrombin time% activity (PT%) ≤80%, and serum creatinine level ≥0.84 mg/dL were poor prognostic factors. Although the Sp + Dev group had more short-term complications after procedures, Sp + Dev tended to be more effective in improving liver function than BRTO.
Conclusions
Sp + Dev showed better OS and improvement of liver function compared with BRTO for the treatment of gastric varices caused by portal hypertension.
Arterial peak enhancement on contrast-enhanced CT (CECT) images is thought to be higher in patients with low cardiac function. Using computer simulations, we tested the hypothesis that the ...relationship between the cardiac index and the aortic peak CT number (PCTN) is affected by the contrast material (CM) injection duration. We created computer simulation software for the contrast enhancement of various organs and vessels based on the Bae pharmacokinetics model and implemented models for CM transmission within organs and CM diffusion in blood plasma based on the osmotic pressure. Aortic contrast enhancement at coronary- and abdominal CT angiographs (CTA) was simulated for a representative 60-year-old Japanese male 166 cm in height and 65.0 kg in weight. The injection protocol for coronary CTA was: CM dose 45.5 ml, iodine dose, 245 mg/kg body weight (BW); injection duration 8-20 sec in 2-sec increments. For abdominal CTA it was CM dose 74.3 ml; iodine dose 400 mg/kg BW; injection duration 10-40 sec in 5-sec increments. In both protocols the iodine concentration was 350 mgI/ml, osmotic pressure was 590 mOsm/kgH2O, and the cardiac index ranged from 0.1-6.0 l/min/m2. Under all protocols, the aortic PCTN increased as the injection duration decreased and as the cardiac index rose to the cardiac index value. It then decreased as it exceeded the cardiac index value. At coronary CTA, at an injection duration of 8 or 10 sec, the PCTN exceeded 350 Hounsfield units (HU) at a cardiac index from 0.9-5.6 l/min/m2. At an HU value greater than 350, the range of the cardiac index narrowed when the injection duration was 12 sec or longer. On abdominal CTA scans performed with an injection duration of 10-, 15-, or 20 sec, the PCTN exceeded 350 HU at a cardiac index ranging from 0.4-5.3 l/min/m2. When the injection duration ranged from 25-40 sec, there was narrowing of the range of the cardiac index at which the PCTN exceeded 350 HU. For coronary and abdominal CTA, contrast enhancement protocols with shorter injection durations yield a diagnostically adequate aortic PCTN at a wide range of cardiac indices.
A double J stent (DJS) is widely used as an ureteral stent these days. A DJS is composed of a shaft and proximal and distal coils, and it has multiple side holes along the stent axis. The role of ...side holes must be a supply of detour. Several studies on side holes have been conducted. Various parameters, such as the number of side holes, the distance between adjacent side holes, and the degree of ureteral stenosis, have been evaluated. Studies have shown that increasing the number of side holes increases the overall flow rate, but it has not presented an important role in the absence of ureteral stenosis. In the absence of ureteral stenosis, only a few proximal and distal side holes show a role of detour, and the flow of urine through a stent is negligible. Here, we examine whether urine flow through a stented ureter is maximized by removing side holes in the midshaft and increasing the number of side holes in the proximal and distal segments of the stent shaft. We establish an undulated curved ureter model and compare a stent with only proximal and distal side holes in the shaft with a stent with side holes along the entire shaft in a point of flow rates in the ureter and flow patterns around side holes. The stent with side holes along the entire shaft (16.5 mL/h) shows a higher total flow rate compared with the stent with only proximal and distal side holes in the shaft (12.7 mL/h).
Background
We developed a method to quantify the volume flow rate (VFR) using the time‐spatial labeling inversion pulse (Time‐SLIP) technique to evaluate salivary function.
Purpose/Hypothesis
To ...investigate the accuracy of quantification of the salivary VFR using the Time‐SLIP technique in phantoms and to examine the feasibility of its use in human subjects.
Study Type
This was a prospective phantom and volunteer study.
Population/Subjects/Phantom/Specimen/Animal Model
A phantom and 23 normal volunteers who fasted at least 2 hours study was performed.
Field Strength/Sequence
Flow images of the phantom and the parotid duct of 23 volunteers were acquired on a 3T‐MRI scanner using the Time‐SLIP technique.
Assessment
Hypothesizing that flow aggregates in the conducting duct, we measured the VFR on flow images. In the phantom study, the actual VFR (slow, medium, fast flow) was controlled by an automatic pump system and the measured VFR was compared with the actual VFR on flow images. In the human study we injected citric acid into the mouth of healthy volunteers to stimulate saliva secretion and recorded the VFR.
Statistical Tests
As this study was a feasibility study, statistical tests were not performed.
Results
In the phantom study, the VFR at slow, medium, and fast flow was 5.7 ± 0.4 (SD), 8.4 ± 0.3, and 12.2 ± 1.1 mm3/sec, respectively. The error between the measured and actual VFR values was 2.8–3.7%. Salivary flow in the parotid duct was visualized in 22 of the 23 volunteers. The mean VFR was 8760 mm3/10 min.
Data Conclusion
When salivary flow was stimulated with citric acid in normal volunteers, the salivary VFR could be obtained using the Time‐SLIP technique.
Level of Evidence: 2
Technical Efficacy: Stage 2
J. Magn. Reson. Imaging 2018;47:928–935.
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