•The SFA can come to a close distance (median 21 mm) to the tip of the screw during the LISS plate fixation of distal femoral fractures.•The SFA can be in the line of drilling when using the LISS ...plate holes’ number 6 to 10.•Extra-vigilance is required when drilling from lateral to medial during LISS plate fixation of distal femoral fractures, especially in the high-risk plate zone.
The incidence of arterial injury associated with femoral fractures is approximately 1%. Lateral sub-muscular plate fixation is gaining popularity for the management of distal femoral fractures. The objective of this study was to assess the iatrogenic risk to the superficial femoral artery (SFA) during Less Invasive Stabilisation System (LISS) plate fixation of distal femoral fractures by analysing the range of distances and angles between LISS plate screws and the drilling line to the SFA.
We identified all patients who underwent LISS plate fixation of distal femoral fractures between 2008 and 2018 in our level-1 trauma centre. Patients who underwent postoperative computed tomography for any reason were eligible for inclusion in the study. Twenty-five patients met the inclusion criteria. The sample comprised 10 male and 15 female patients with a mean age of 55 years. The most common fracture type was a supracondylar femur fracture (56%), followed by an intercondylar fracture (36%). A 13-hole LISS plate was the most common plate length used (44%). A consultant radiologist reviewed all scans to verify the visibility and marking of the SFA.
The median distance between the screw tip and the SFA was 21 mm (range, 8–65 mm). There was a negative correlation between the LISS plate hole number and the trajectory of drilling (Pearson coefficient: −0.87, p < 0.001). Using a linear regression model, the SFA was more likely to be in the line of drilling when the 6th to 10th holes in the LISS plate were used.
Extra care is needed when drilling into the LISS plate holes from the lateral to the medial direction in order to reduce the risk of iatrogenic injury to the SFA, especially in the high-risk plate zone where the artery can be close to the drilling line.
Background
In recent years, four-dimensional computed tomography (4DCT) has emerged as a new localization study for primary hyperparathyroidism (pHPT).
Objective
We aimed to assess the added value of ...4DCT in our institution in the first 4 years of use.
Methods
A retrospective cohort study was conducted from February 2004 to June 2015. Since 2011, patients over 50 years of age without concordant sestamibi-SPECT (SeS) and ultrasound (US) findings underwent 4DCT. Imaging results, surgical findings, histopathology, and postoperative biochemistry were collected.
Results
A total of 536 parathyroid operations in 510 patients were performed during the study period. The overall cure rate was 99.2% after reoperation in some patients, and the overall sensitivity for SeS was 76.0%, and 74.8% for US. Since 2011, 100 patients without concordant SeS/US findings have undergone 4DCT, with a sensitivity of 72.9%. This is in comparison to the sensitivities for SeS (48.3%) and US (52.3%). 4DCT was more sensitive in patients with persistent/recurrent disease (60.0% compared with SeS 43.8% and US 36.4%) and patients with multigland disease (67.4% compared with SeS 40.9% and US 42.1%). Comparison between outcomes in the pre- versus post-CT era demonstrated no difference in the initial cure rate (95.4 vs. 95.9%,
p
= 0.85) or the rate of minimally invasive parathyroidectomies (74.5 vs. 79.9%,
p
= 0.22).
Conclusion
Parathyroid 4DCT can aid surgical planning in cases without concordant SeS/US findings; however, the introduction of 4DCT as a second-line test did not change our overall cure rate or rate of minimally invasive parathyroidectomy. The role of 4DCT as the primary localization study for pHPT merits further investigation.
The use of gadolinium-based hepatocyte-specific contrast agents (HSCAs) has increased markedly since their introduction, and hepatocellular phase imaging performed with an HSCA is now a key part of ...the standard magnetic resonance (MR) imaging work-up for focal liver lesions. An understanding of the mechanisms of action of HSCAs helps ensure their effective use. The optimal delay for hepatocellular phase image acquisition differs between the two currently available HSCAs, gadoxetic acid and gadobenate dimeglumine, and MR imaging protocols must be adjusted accordingly. In addition, familiarity with typical and atypical appearances of benign and malignant focal liver lesions at HSCA-enhanced hepatocellular phase MR imaging, along with knowledge of the processes that are most likely to produce atypical appearances, is required to achieve optimal diagnostic accuracy.
Abdominal donor-site flaps, including the transverse rectus abdominis musculocutaneous (TRAM) and deep inferior epigastric artery (DIEA) perforator flaps, are standard in autologous breast ...reconstruction. With significant variation in the vascular anatomy of the abdominal wall, preoperative imaging is essential for preoperative planning and reducing intraoperative error. Doppler and color duplex sonography have been used with varying results, and the quest continues for optimal preoperative assessment. Computed tomographic angiography has recently been proposed as a noninvasive modality for this purpose. This is the first study to formally compare preoperative Doppler ultrasound with computed tomographic angiography for imaging the DIEA.
Eight consecutive patients undergoing DIEA perforator flap surgery for breast reconstruction underwent both computed tomographic angiography and Doppler ultrasound preoperatively. All investigations and procedures were performed at the same institution with the same primary and assisting surgeons and the same radiology team.
Computed tomographic angiography was superior to Doppler ultrasound at identifying the course of the DIEA and its branching pattern, and in visualizing its perforators. Preoperative computed tomographic angiography was highly specific (100 percent) and more sensitive in mapping and visualizing perforators (p = 0.0078). It was also proficient at identifying the superficial epigastric arterial system and for effectively displaying the results intraoperatively. It was substantially quicker and removed the interobserver error associated with Doppler ultrasonography. The study was ceased after eight patients because of the overwhelming benefit of computed tomographic angiography over Doppler ultrasonography.
Computed tomographic angiography is a valuable imaging modality for the preoperative assessment of the donor-site vascular supply for TRAM and DIEA perforator flaps.
Dynamic CT is increasingly used for preoperative localization of parathyroid adenomas, but concerns remain about the radiation effective dose of CT compared with that of
Tc-sestamibi scintigraphy. ...The purpose of this study was to compare the radiation dose delivered by three-phase dynamic CT with that delivered by
Tc-sestamibi SPECT/CT performed in accordance with our current protocols and to assess the possible reduction in effective dose achieved by decreasing the scan length (i.e., z-axis) of two phases of the dynamic CT protocol.
The effective dose of a
Tc-sestamibi nuclear medicine parathyroid study performed with and without coregistration CT was calculated and compared with the effective dose of our current three-phase dynamic CT protocol as well as a proposed protocol involving CT with reduced scan length.
The median effective dose for a
Tc-sestamibi nuclear medicine study was 5.6 mSv. This increased to 12.4 mSv with the addition of coregistration CT, which is higher than the median effective dose of 9.3 mSv associated with the dynamic CT protocol. Reducing the scan length of two phases in the dynamic CT protocol could reduce the median effective dose to 6.1 mSv, which would be similar to that of the dose from the
Tc-sestamibi study alone.
Dynamic CT used for the detection of parathyroid adenoma can deliver a lower radiation dose than
Tc-sestamibi SPECT/CT. It may be possible to reduce the dose further by decreasing the scan length of two of the phases, although whether this has an impact on accuracy of the localization needs further investigation.
The analysis of
C-labeled lipids by mass spectrometry is challenging due to the complexity from labeling the large number of carbon atoms in lipids. To further add to the complexity, different ...adducts can be produced during electrospray ionization and in-source fragmentation, which can create complex overlapping isotope patterns that can only be resolved using high-resolution mass spectrometry. Co-elution of lipids even after chromatographic separation also adds to the potential for overlapping mass spectra. Here, we describe a procedure that enables full
C-labeled patterns to be resolved in complex microalgal lipid extracts as well a procedure that provides structural labeling information. Mass resolving powers of 240000 full width half-maximum (fwhm) and fast targeted MS/MS allowed the differentiation of isotopologues, adducts, and unresolved lipid species after chromatographic separation. This enabled the percentage of
C enrichment to be calculated for each individual lipid species over a time series in the microalgal lipidome. The application of tandem mass spectrometry (MS/MS) also allowed the degree of labeling within the headgroup vs acyl chains to be determined, further adding to the detail of information collected. This information is particularly useful for studying lipid synthesis and remodeling processes and can be extended to other biological systems.
Background:
Following reperfusion treatment in ischemic stroke, computed tomography (CT) imaging at 24 h is widely used to assess radiological outcomes. Even without visible hyperattenuation, occult ...angiographic contrast may persist in the brain and confound Hounsfield unit-based imaging metrics, such as net water uptake (NWU).
Aims:
We aimed to assess the presence and factors associated with retained contrast post-thrombectomy on 24-h imaging using dual-energy CT (DECT), and its impact on the accuracy of NWU as a measure of cerebral edema.
Methods:
Consecutive patients with anterior circulation large vessel occlusion who had post-thrombectomy DECT performed 24-h post-treatment from two thrombectomy stroke centers were retrospectively studied. NWU was calculated by interside comparison of HUs of the infarct lesion and its mirror homolog. Retained contrast was quantified by the difference in NWU values with and without adjustment for iodine. Patients with visible hyperdensities from hemorrhagic transformation or visible contrast retention and bilateral infarcts were excluded. Cerebral edema was measured by relative hemispheric volume (rHV) and midline shift (MLS).
Results:
Of 125 patients analyzed (median age 71 (IQR = 61–80), baseline National Institutes of Health Stroke Scale (NIHSS) 16 (IQR = 9.75–21)), reperfusion (defined as extended-Thrombolysis-In-Cerebral-Infarction 2b–3) was achieved in 113 patients (90.4%). Iodine-subtracted NWU was significantly higher than unadjusted NWU (17.1% vs 10.8%, p < 0.001). In multivariable median regression analysis, increased age (p = 0.024), number of passes (p = 0.006), final infarct volume (p = 0.023), and study site (p = 0.021) were independently associated with amount of retained contrast. Iodine-subtracted NWU correlated with rHV (rho = 0.154, p = 0.043) and MLS (rho = 0.165, p = 0.033) but unadjusted NWU did not (rHV rho = –0.035, p = 0.35; MLS rho = 0.035, p = 0.347).
Conclusions:
Angiographic iodine contrast is retained in brain parenchyma 24-h post-thrombectomy, even without visually obvious hyperdensities on CT, and significantly affects NWU measurements. Adjustment for retained iodine using DECT is required for accurate NWU measurements post-thrombectomy. Future quantitative studies analyzing CT after thrombectomy should consider occult contrast retention.
Institutional review board approval was obtained for this study, and all patients gave written informed consent. Autologous surgical breast reconstruction with use of abdominal wall donor flaps based ...on the deep inferior epigastric artery (DIEA) and one or more of its anterior musculocutaneous perforating branches (DIEA perforator flap) is being used with increasing frequency instead of breast reconstruction with use of traditional transverse rectus abdominus musculocutaneous and modified muscle-sparing flaps. Preoperative mapping of the DIEA perforators with abdominal wall computed tomographic (CT) angiography may improve patient care by providing the surgeon with additional information that will lead to optimization of the surgical technique, shorter procedure time, and reduction in the frequency of surgical complications. The branching patterns of the DIEA, the segmental anatomy of the anterior adipocutaneous perforating branches of the DIEA, and the importance of these features in pre- and intraoperative surgical planning necessitate a different approach to abdominal wall CT angiography than that used with other abdominal CT angiographic techniques. In abdominal wall CT angiography, the common femoral artery is used as the bolus trigger, CT scanning is performed in the caudocranial direction, the automatic exposure control feature is disabled, a scaled grid overlay tool is used to present information to the surgeons, and radiation dose is minimized (average dose, 6 mSv). The anatomic accuracy of abdominal wall CT angiography has been investigated in cadaveric and surgical studies, with sensitivity of 96%-100% and specificity of 95%-100%. This detailed description will allow other radiologists and surgeons interested in free DIEP flap surgery to incorporate this useful tool into their practice.
The deep inferior epigastric artery perforator flap is increasingly used for autologous breast reconstruction, with low donor-site morbidity cited as a major advantage of this operation. Preoperative ...imaging of the donor-site vasculature is frequently used as a further means of improving operative outcome. Computed tomographic angiography has been increasingly described as a preferred imaging modality; however, its formal evaluation has not been described in a clinical setting.
A prospective, single-blind, cohort study was undertaken on 60 consecutive patients for whom deep inferior epigastric artery perforator flap surgery had been planned. Patients who did not undergo the procedure during the study period were excluded, with 42 patients ultimately included in the study. All computed tomographic angiography scans were obtained at a single institution. Perforators were mapped both on angiography and intraoperatively using a grid of 4-mm squares centered on the umbilicus. Only perforators larger than 1 mm were included in the study. All imaging findings were recorded by a single operator, and all intraoperative findings were recorded by the operating surgeon.
Computed tomographic angiography identified 280 major perforators in 42 patients. It was highly accurate, demonstrating 279 perforators recorded accurately, with one false-positive and one false-negative. Its sensitivity for mapping perforators was thus 99.6 percent, with a positive predictive value of 99.6 percent.
Computed tomographic angiography is highly accurate in identifying and mapping the perforators of the deep inferior epigastric artery. Its accuracy is superior to that of the previous modalities used in this role and suggests the usefulness of this technique before deep inferior epigastric artery perforator flap surgery for breast reconstruction.
