The efficacy of i. v. thrombolysis in acute stroke with high clot burden is limited. Successful recanalization is very unlikely if the thrombus length exceeds 7 mm. Thus this retrospective controlled ...study evaluated the efficacy and safety of neurothrombectomy in the treatment of acute embolic stroke in patients selected by a thrombus length of ≥ 8 mm using the stent retriever Trevo(®) device.
40 patients with acute occlusion of the anterior intracranial arteries with a thrombus length of ≥ 8 mm were treated with neurothrombectomy. We compared the outcome with a historical cohort of 42 patients with a thrombus length of ≥ 8 mm that received i. v. thrombolysis only. Clinical outcome was assessed by modified Rankin scale in both groups at discharge and on day 90.
Patients did not differ in age, mRS on admission, thrombus length or time from symptom onset to i. v. thrombolysis, but the thrombectomy group had higher NIHSS on admission. Successful recanalization was achieved in 33/40 patients (83 %) with neurothrombectomy. 15 patients received i. v. thrombolysis prior to neurothrombectomy. Median mRS at discharge was 3.5 (1.25 - 5) vs. 5 (4 - 6; p < 0.01) and on day 90 3 (1 - 4) vs. 5 (4 - 6; p < 0.01). Symptomatic hemorrhage occurred in 3 vs. 7 patients. 3 vs. 17 patients died within 90 days (thrombectomy vs. control each). There were only a few intervention-related complications.
Thrombectomy in acute stroke with high clot burden using the Trevo(®) device has a low risk and improved clinical outcome compared to i. v. thrombolysis alone. Treatment selection by a clot length of ≥ 8 mm might be a powerful approach to improve the outcome of mechanical thrombectomy.
• Clot length of ≥ 8 mm might be a valuable criterion for indicating neurothrombectomy. • Thrombolysis only in high clot burden is associated with poor clinical outcome. • Thrombectomy using the Trevo(®) stent retriever is safe and effective.
A group of 59 patients with stroke due to acute vertebrobasilar or carotid territory occlusion have been treated by local intra-arterial fibrinolysis (LIF). A high recanalisation rate was ...accomplished with either urokinase or recombinant tissue plasminogen activator (r-TPA). However, with either substance, even if a high dose was used, recanalisation was a time-consuming process which usually took 120 min. A reasonable explanation for the lack of effectiveness of these plasminogen-activating substances might be a deficit of substrate, e.g. plasminogen, in aged thrombus. LIF was capable of improving clinical outcome in acute vertebrobasilar artery occlusion, reducing mortality to 50% in patients fulfilling inclusion criteria. In the carotid territory multiple occlusions had a poor prognosis while good clinical results could be achieved in occlusions of the proximal middle cerebral artery or single branches.
A meta-analysis of data primarily from PET oncologic investigations using FDG PET was performed. Its purpose was to establish statistical features of the distributions of standardized uptake values ...(SUVs) as possible aids in the diagnostic process.
We obtained 1536 values of oncologic markers from patient studies of 40 investigations in the literature. Statistical parameters were tabulated for analysis.
A significant observation is that, unlike skewed SUV histograms, log10SUV has Gaussian behavior, which is not uncommon for biologic quantities. This was found for SUVs of FDG and 2 amino acids as well as a few other cancer markers. A possible model for explaining this is proposed. For FDG, the SD sigma of the log10SUVs for an average cancer category was 0.23. Examining data within the framework of the model points to physiologic factors as dominating SUV variability rather than PET protocols. When data for a single cancer category were available from multiple institutions, averages, mean(SUV)s, disagree beyond chance expectations. Diagnostic utility suggestions include a universal linear relationship between sensitivity and severity, defined as SUV/mean(SUV), on semilogarithmic probability paper; a generic receiver-operating-characteristic curve for all cancers; using log10(mean(SUVmal)/mean(SUVnorm)) divided by (sigma(mal)2 + sigma(norm)2)(1/2) as a simple diagnostic effectiveness measure; and using Gaussian log10SUVs to avoid erroneous P values.
Using the logarithms of markers, such as SUVs, several advantages stemming from their Gaussian nature can be achieved with benefits ensuing to the diagnostic process.
Purpose
The intention here is to enhance the usefulness of the Gjedde–Patlak plot of dynamic positron emission tomography (PET) tracer uptake. Two additional parameters closely related to the ...physiologically significant and diagnostically useful phosphorylation rate
k
3
are therefore studied. Additionally, their inter-institutional transportability is examined.
Methods
The two traditional parameters obtained from a Patlak plot are its slope
Ki
and its usually ignored tissue/plasma (=
Q
/
Cp
) axis intercept
V
. As a useful result, a normalized uptake rate may be defined as
k
=
Ki
/
V
. This is can be theoretically close to
k
3
. Similar to this an alternative normalized uptake rate is defined as
k
3
′ =
Ki
/
V
′. Here,
V
′ would be a composite of model rate constants, reasonably known a priori, and the measured
V
so as to depend less on errors in the latter. Parameter determination demonstrations utilize data from the 2-deoxy-2-F-18fluoro-D-glucose(FDG)-PET literature.
Results
Using median
k
i
values from 24 FDG dynamic studies and algebraic relationships, on average:
k
= 1.07
k
3
(
r
= 0.97), and
k
3
′ = 0.95
k
3
(
r
= 0.91). A skeletal muscle case also demonstrates agreements with
k
3
. For liver malignancies
k
and
k
3
′ can be diagnostically slightly superior to
Ki
. Unaffected by institutionally dependent
Q
and
Cp
calibrations and methods, these can be more robust than
Ki
in a number of circumstances.
Conclusion
Two studied physiologically meaningful parameters, close to the diagnostically important
k
3
, can supplement
Ki
and enhance Patlak analysis by appropriately utilizing normally ignored information. Hitherto,
k
3
was obtainable only by complex nonlinear least squares compartmental model analysis. The additional parameters can have more robust inter-institutional transportability than
Ki
.
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