Ex Vivo Repair and Renal Autotransplantation for Complex Renal Artery Aneurysms in a Solitary Kidney

Renal artery aneurysm (RAA) is a rare clinical entity with an incidence of 0.015-1%. Indications for interventional or surgical repair of RAAs are expanding aneurysms, diameter >2.5 cm, intractable renovascular hypertension, dissecting RAA, hematuria, and renal infarction after distal embolization. Interventional insertion of a stent graft as well as aortorenal bypass implantation are both low-risk procedures in simple aneurysms of the proximal renal artery. However, complex distal renal aneurysms involving several renal artery branches require not only an excellent result of vascular reconstruction, but also a surgical technique offering maximal protection for the kidney during the ischemic period. Here, we present a case of a solitary kidney with two consecutive RAAs of segmental renal artery branches (type 2 RAA). A surgical strategy including renal explantation, ex vivo renal preservation, ex vivo reconstruction of the renal artery, and renal heterotopic autotransplantation was successfully applied. The technique of ex vivo repair is a safe and effective surgical procedure in this clinical setting.     

CT-guided high-dose-rate brachytherapy of unresectable hepatocellular carcinoma

Strahlentherapie und Onkologie - The purpose of the present study was to evaluate the clinical outcome of CT-guided high-dose-rate brachytherapy (CT-HDRBT) in patients with unresectable...     

Fokus Neurochirurgische Intensivmedizin 2021/2022

Die Anaesthesiologie -     

Image quality and radiation dose of low tube voltage 3rd generation dual-source coronary CT angiography in obese patients: a phantom study

Objectives

To assess the influence of tube potential on radiation dose and image quality of third-generation dual-source coronary CT angiography (CTA) in a phantom simulating an obese patient.

Methods

A thoracic phantom was equipped with tubular inserts containing iodine solution and water. A soft-tissue-equivalent ring around the phantom simulated an obese patient. Images were acquired at tube potentials of 80, 100, 120 and 140 kV with second-generation dual-source CT (DSCT) and 70–150 kV (in 10-kV increments) with third-generation DSCT. Contrast-to-noise ratio (CNR) was calculated and CT dose index was recorded.

Results

With second-generation DSCT, CNR was highest for 120 kV (19.0) and decreased with lower tube potential (12.0 at 80 kV) owing to disproportionately increased image noise. With third-generation DSCT, 70- and 80-kV acquisitions showed a smaller increase in noise. CNRs for third-generation DSCT were highest for 70 and 80 kV (21.1 and 21.2, respectively). Compared to 120 kV, radiation dose was 68 % and 49 % lower at 70 kV and 80 kV, respectively.

Conclusion

Third-generation DSCT enables one to perform coronary CTA at 70–80 kV in obese patients without compromising CNR and thus reduces radiation dose by 49–68 %.

Key points

? Low tube potential CT angiography is currently not suitable for obese patients. ? Third-generation DSCT offers substantially increased tube power at low tube potential. ? This enables one to perform coronary CT angiography at 70–80 kV in obese patients. ? Signal-to-noise ratio is maintained owing to increased tube current. ? This approach can be expected to reduce radiation dose by 49–68 %.     

Performance of turbo high-pitch dual-source CT for coronary CT angiography: first ex vivo and patient experience

Objectives

To evaluate image quality, maximal heart rate allowing for diagnostic imaging, and radiation dose of turbo high-pitch dual-source coronary computed tomographic angiography (CCTA).

Methods

First, a cardiac motion phantom simulating heart rates (HRs) from 60-90 bpm in 5-bpm steps was examined on a third-generation dual-source 192-slice CT (prospective ECG-triggering, pitch 3.2; rotation time, 250 ms). Subjective image quality regarding the presence of motion artefacts was interpreted by two readers on a four-point scale (1, excellent; 4, non-diagnostic). Objective image quality was assessed by calculating distortion vectors. Thereafter, 20 consecutive patients (median, 50 years) undergoing clinically indicated CCTA were included.

Results

In the phantom study, image quality was rated diagnostic up to the HR75 bpm, with object distortion being 1 mm or less. Distortion increased above 1 mm at HR of 80-90 bpm. Patients had a mean HR of 66 bpm (47-78 bpm). Coronary segments were of diagnostic image quality for all patients with HR up to 73 bpm. Average effective radiation dose in patients was 0.6?±?0.3 mSv.

Conclusions

Our combined phantom and patient study indicates that CCTA with turbo high-pitch third-generation dual-source 192-slice CT can be performed at HR up to 75 bpm while maintaining diagnostic image quality, being associated with an average radiation dose of 0.6 mSv.

Key points

? CCTA is feasible with the turbo high-pitch mode. ? Turbo high-pitch CCTA provides diagnostic image quality up to 73 bpm. ? The radiation dose of high-pitch CCTA is 0.6 mSv on average.     

Automated tube voltage adaptation in head and neck computed tomography between 120 and 100 kV: effects on image quality and radiation dose

Introduction

Low tube voltage allows for computed tomography (CT) imaging with increased iodine contrast at reduced radiation dose. We sought to evaluate the image quality and potential dose reduction using a combination of attenuation based tube current modulation (TCM) and automated tube voltage adaptation (TVA) between 100 and 120 kV in CT of the head and neck.

Methods

One hundred thirty consecutive patients with indication for head and neck CT were examined with a 128-slice system capable of TCM and TVA. Reference protocol was set at 120 kV. Tube voltage was reduced to 100 kV whenever proposed by automated analysis of the localizer. An additional small scan aligned to the jaw was performed at a fixed 120 kV setting. Image quality was assessed by two radiologists on a standardized Likert-scale and measurements of signal- (SNR) and contrast-to-noise ratio (CNR). Radiation dose was assessed as CTDI_vol.

Results

Diagnostic image quality was excellent in both groups and did not differ significantly (p?=?0.34). Image noise in the 100 kV data was increased and SNR decreased (17.8/9.6) in the jugular veins and the sternocleidomastoid muscle when compared to 120 kV (SNR 24.4/10.3), but not in fatty tissue and air. However, CNR did not differ statistically significant between 100 (23.5/14.4/9.4) and 120 kV data (24.2/15.3/8.6) while radiation dose was decreased by 7–8 %.

Conclusions

TVA between 100 and 120 kV in combination with TCM led to a radiation dose reduction compared to TCM alone, while keeping CNR constant though maintaining diagnostic image quality.     

Prevalence of extraforaminal nerve root compression below lumbosacral transitional vertebrae

Objective

Although pathology at the first mobile segment above a lumbosacral transitional vertebra (LSTV) is a known source of spinal symptoms, nerve root compression below an LSTV, has only sporadically been reported. Our objective was to assess the prevalence of nerve root entrapment below an LSTV, review the causes of entrapment, and correlate with presenting symptoms.

Materials and methods

A retrospective review of MR and CT examinations of the lumbar spine was performed over a 5.5-year period in which the words “transitional vertebra” were mentioned in the report. Nerve root compression below an LSTV was assessed as well as the subtype of transitional vertebra. Correlation with clinical symptoms at referral was made. MR and CT examinations were also reviewed to exclude any other cause of symptoms above the LSTV.

Results

One hundred seventy-four patients were included in the study. Neural compression by new bone formation below an LSTV was demonstrated in 23 patients (13 %). In all of these patients, there was a pseudarthrosis present on the side of compression due to partial sacralization with incomplete fusion. In three of these patients (13 %), there was symptomatic correlation with no other cause of radiculopathy demonstrated. A further 13 patients (57 %) had correlating symptoms that may in part be attributable to compression below an LSTV.

Conclusions

Nerve root compression below an LSTV occurs with a prevalence of 13 % and can be symptomatic in up to 70 % of these patients. This region should therefore be carefully assessed in all symptomatic patients with an LSTV.     

Long-term impact of chronic hemodialysis on glycemic control and serum lipids in insulin-treated type 2-diabetic patients

There are only a few data in the literature concerning metabolic control in insulin-treated diabetic patients with end stage renal disease (ESRD). The aim of the study was to find out the long-term impact of hemodialysis on glycemic control and lipid values in type 2 diabetic patients. Twenty insulin-treated type 2 diabetic patients (age 62 +/- 9 years, f:m=6:14) were evaluated. We compared HbAlc, fasting blood glucose (FBG), body weight, serum lipids, insulin requirement, and blood-pressure (BP) 12 and 6 months before dialysis, at the start of dialysis, and 6 as well as 12 months after the start. RESULTS: The mean HbA1c- and FBG-values were not significantly different before and after the start of dialysis therapy. The average insulin requirement was 26 +/- 10 IU/day in the predialysis period, 25 +/- 12 IU/day at the start, and 24 +/- 13 as well as 22 +/- 13 IU/day after the start of dialysis. The mean cholesterol level fell significantly from 199 +/- 63 and 190 +/- 49 mg/dL in the predialysis phase to 167 +/- 62 and 157 +/- 38 mg/dL after dialysis began. The triglyceride concentrations decreased only slightly after the start of dialysis. The incidence of hypoglycemia (n/patient/month) was markedly lower in the predialysis phase (0.4 vs. 0.6, NS) than after start of dialysis. In patients with residual diuresis (<500 mL urine/day) the needed insulin doses decreased significantly by 29% compared to patients with higher residual diuresis, whose insulin requirement remained unchanged. In summary, hemodialysis had no significant long-term effect on glycemic control in insulin-treated type 2 diabetic patients, but incidence of hypoglycemia tended to be higher under hemodialysis than in the predialysis period. Lipid levels tended to be lower after the initiation of dialysis therapy. Insulin requirement under hemodialysis decreased only in patients with loss of residual urine volume (below 500 mL urine/day).     

Differences in CMV-Specific T-Cell Levels and Long-Term Susceptibility to CMV Infection after Kidney, Heart and Lung Transplantation

Patients after kidney, heart and lung transplantation differ in their immunosuppressive drug regimens and in susceptibility to infectious complications with cytomegalovirus (CMV). In this study, CMV-specific T-cell responses were characterized in long-term transplant recipients and associated with the frequency of infectious complications. CMV-reactive CD4 T cells from 50 healthy controls, 68 renal, 14 heart and 24 lung transplant recipients were flow cytometrically quantified by the induction of cytokines after specific stimulation. Moreover, the immunosuppressive effect of calcineurin inhibitors on specific T-cell reactivity was quantified in vitro and compared with responses in vivo. Median CMV-specific T-cell frequencies in long-term renal (1.48%; range 0.06-17.26%) and heart transplant recipients (0.90%; 0.13-12.49%) did not differ from controls (1.82%; 0.26-21.00%). In contrast, CMV-specific T-cell levels were significantly lower in lung transplant recipients (0.50%; <0.05-4.98%) and showed a significant correlation with the frequency of infectious episodes (r =-0.57, p = 0.005). The differences within the groups were associated with increasing dosages of immunosuppressive drugs, as exemplified for calcineurin inhibitors that dose dependently reduced specific T-cell reactivity in vitro. In conclusion, monitoring CMV-specific CD4 T cells may serve as a measure for long-term disease susceptibility and may contribute to an improved management of CMV complications after lung transplantation.