The correlation between CT perfusion deficits and immediate post-endovascular treatment contrast extravasation on dual energy CT in acute ischemic stroke patients

PURPOSE

After endovascular therapy (EVT) for ischemic stroke, post-EVT CT imaging often shows areas of contrast extravasation (CE) caused by blood brain barrier disruption (BBBD). Before EVT, CT-perfusion (CTP) can be used to estimate salvageable tissue (penumbra) and irrevocably damaged infarction (core). In this study, we aimed to correlate CTP deficits to CE, as a surrogate marker for BBBD, after EVT for ischemic stroke.

METHODS

In this single center study, EVT patients between 2010 and 2020 in whom both CTP at baseline and DECT post-EVT was performed were included. The presence of core and penumbra on CTP was assessed per ASPECTS region, resulting in a CTP-ASPECTScore and a CTP-ASPECTScore+penumbra. Likewise, CE on DECT was scored per ASPECTS region, resulting in a CE-ASPECTS. Correlation was assessed using Kendall's tau correlation and positive predictive values (PPV) were calculated per ASPECTS region. Bland-Altman plots were created to visualize the agreement between the two scores.

RESULTS

194 patients met our inclusion criteria. The median core and penumbra were 8 cc (IQR 1-25) and 103 cc (IQR 68-141), respectively. The median CTP-ASPECTScore, CTP-ASPECTScore+penumbra, and CE-ASPECTS were 7 (IQR 4-9), 3 (IQR 1-4), and 6 (IQR 4-9), respectively. The correlation between CTP-ASPECTScore and CE-ASPECTS was τ = 0.21, P <.001, and τ = 0.13, P =.02 between CTP-ASPECTScore+penumbra and CE-ASPECTS. Bland-Altman plots showed a mean difference (CTP-ASPECTS minus CE-ASPECTS) of 0.27 (95 %CI -6.7-7.2) for CTP-ASPECTScore and -3.2 (95 %CI -9.7-3.2) for CTP-ASPECTScore+penumbra. The PPVs of the CTP-ASPECTScore and CTP-ASPECTScore+penumbra were highest for the basal ganglia.

CONCLUSION

There is a weak although significant correlation between pre-EVT CTP-ASPECTS and post-EVT CE-ASPECTS. The weak correlation may be attributed to various imaging limitations as well as patient related factors.

Procedural Blood Pressure and Intracranial Hemorrhage on Dual-Energy Computed Tomography After Endovascular Stroke Treatment

PURPOSE

Optimal systolic blood pressure (SBP) management during endovascular treatment (EVT) for acute ischemic stroke remains a topic of debate. Though BP is associated with worse functional outcome, the relationship between BP and post-procedural intracranial hemorrhage (ICH) is less well-known. We aimed to investigate the association between BP during EVT and post-procedural ICH on dual-energy CT (DECT).

METHODS

We included all patients who underwent EVT for an anterior circulation large vessel occlusion between 2010 and 2019, and received DECT < 3 h post-EVT. All BP measurements during the EVT procedure were used to calculate mean arterial pressure (MAPmean), mean SBP (SBPmean), and SBPmax-min (highest minus lowest). ICH was assessed using virtual post-procedural unenhanced DECT reconstructions and classified as intraparenchymal or extraparenchymal. Symptomatic ICH was scored according to the Heidelberg criteria. The association between different BP parameters and ICH was assessed using multivariable logistic regression.

RESULTS

We included 478 patients. Seventy-six patients (16%) demonstrated ICH on DECT, of which 26 (34%) were intraparenchymal. Symptomatic intraparenchymal and extraparenchymal ICH occurred in 10 (38%) and 4 (8%) patients. SBPmax, SBPmean, and MAPmean were associated with intraparenchymal ICH with an adjusted odds ratio of 1.19 (95%CI, 1.02-1.39), 1.22 (95%CI, 1.03-1.46), and 1.40 (95%CI, 1.09-1.81) per 10 mmHg, while BP was not significantly associated with extraparenchymal ICH. BP did not differ between asymptomatic and symptomatic ICH.

CONCLUSION

Procedural BP is associated with intraparenchymal ICH on post-EVT DECT but not with extraparenchymal ICH. Future studies should evaluate whether individual procedural BP management reduces post-EVT ICH and improves clinical outcome.

Procedural blood pressure and contrast extravasation on dual energy computed tomography after endovascular stroke treatment

BACKGROUND

Blood brain barrier disruption (BBBD) can be visualized by contrast extravasation (CE) after endovascular treatment (EVT) in patients with acute ischemic stroke. Elevated blood pressure is a risk factor for BBBD. However, the association between procedural blood pressure and CE post-EVT is unknown.

METHODS

In this single-center retrospective study, we analyzed 501 eligible patients who received a dual energy CT (DECT) immediately post-EVT for acute ischemic stroke. Procedural blood pressure values (SBPmean, SBPmax, SBPmax-min, and MAPmean) were collected. CE was quantified by measuring the maximum parenchymal iodine concentration on DECT iodine overlay map reconstructions. As a measure for the extent of BBBD, we created CE-ASPECTS by deducting one point per hyperdense ASPECTS region on iodine overlay maps. The association between blood pressure and CE was assessed using multivariable linear regression.

RESULTS

The procedural SBPmean, SBPmax, and MAPmean were 150 ± 26 mmHg, 173 ± 29 mmHg, and 101 ± 17 mmHg, respectively. The median maximum iodine concentration on post-EVT DECT was 1.2 mg/ml (IQR 0.7-2.0), and median CE-ASPECTS was 8 (IQR 5-11). The maximum iodine concentration was not associated with blood pressure. SBPmean, SBPmax, and MAPmean were significantly associated with CE-ASPECTS (per 10 mmHg, β = -0.2, 95 % CI -0.31 to -0.09, β = -0.15, 95 % CI -0.25 to -0.06, β = -0.33, 95 % CI -0.49 to -0.17, respectively).

CONCLUSION

In acute ischemic stroke patients undergoing EVT, particularly in patients achieving successful recanalization, SBPmean, SBPmax, and MAPmean are associated with the extent of BBBD on immediate post-EVT DECT, but not with maximum iodine concentration.

The TRACK-PD study: protocol of a longitudinal ultra-high field imaging study in Parkinson's disease

BACKGROUND

The diagnosis of Parkinson's Disease (PD) remains a challenge and is currently based on the assessment of clinical symptoms. PD is also a heterogeneous disease with great variability in symptoms, disease course, and response to therapy. There is a general need for a better understanding of this heterogeneity and the interlinked long-term changes in brain function and structure in PD. Over the past years there is increasing interest in the value of new paradigms in Magnetic Resonance Imaging (MRI) and the potential of ultra-high field strength imaging in the diagnostic work-up of PD. With this multimodal 7 T MRI study, our objectives are: 1) To identify distinctive MRI characteristics in PD patients and to create a diagnostic tool based on these differences. 2) To correlate MRI characteristics to clinical phenotype, genetics and progression of symptoms. 3) To detect future imaging biomarkers for disease progression that could be valuable for the evaluation of new therapies.

METHODS

The TRACK-PD study is a longitudinal observational study in a cohort of 130 recently diagnosed (≤ 3 years after diagnosis) PD patients and 60 age-matched healthy controls (HC). A 7 T MRI of the brain will be performed at baseline and repeated after 2 and 4 years. Complete assessment of motor, cognitive, neuropsychiatric and autonomic symptoms will be performed at baseline and follow-up visits with wearable sensors, validated questionnaires and rating scales. At baseline a blood DNA sample will also be collected.

DISCUSSION

This is the first longitudinal, observational, 7 T MRI study in PD patients. With this study, an important contribution can be made to the improvement of the current diagnostic process in PD. Moreover, this study will be able to provide valuable information related to the different clinical phenotypes of PD and their correlating MRI characteristics. The long-term aim of this study is to better understand PD and develop new biomarkers for disease progression which may help new therapy development. Eventually, this may lead to predictive models for individual PD patients and towards personalized medicine in the future.

TRIAL REGISTRATION

Dutch Trial Register, NL7558 . Registered March 11, 2019.

A Persistent Foramen of Huschke: A Small Road to Misery in Necrotizing External Otitis

BACKGROUND AND PURPOSE

Necrotizing external otitis is a serious complication of external otitis with different spreading patterns. A persistent foramen of Huschke is a dehiscence located antero-inferior in the osseous external ear canal and posterior-medial to the temporomandibular joint. This dehiscence can facilitate extension of infection in an anterior pattern next to classic spread along the fissures of Santorini. The aim of this study was to define the prevalence and size of a persistent foramen of Huschke in patients with necrotizing external otitis.

MATERIALS AND METHODS

We retrospectively examined 78 CT temporal bone studies (39 patients with necrotizing external otitis, 39 control subjects). The side and presence of the foramen were noted, and its prevalence was calculated. The maximal width of the foramen of Huschke was measured in the axial plane and classified as subtle, mild, moderate, or extensive.

RESULTS

A persistent foramen of Huschke was present in 21 patients (26 ears) and 7 control subjects (9 ears). Prevalence was 50% (20/40) and 11.5% (9/78) in affected ears of patients with necrotizing external otitis and control subjects, respectively. Almost all affected ears showed an anterior distribution pattern of necrotizing external otitis. The extensive dehiscence was most common in affected ears.

CONCLUSIONS

An anterior necrotizing external otitis spreading pattern is associated with the presence and increased size of a persistent foramen of Huschke. These findings facilitate the theory that a persistent foramen of Huschke is an additional risk factor the development of necrotizing external otitis.

The diagnostic accuracy of 1.5 T versus 3 T non-echo-planar diffusion-weighted imaging in the detection of residual or recurrent cholesteatoma in the middle ear and mastoid

PURPOSE AND BACKGROUND

This study retrospectively compares diagnostic performance of 1.5 T versus 3 T non-echo planar diffusion weighted imaging with or without additional T1 and T2 sequences in the detection of residual and/or recurrent cholesteatoma.

METHODS

Patients with clinically suspected recurrent cholesteatoma or postoperative routine survey MR who subsequently underwent surgical procedure were retrospectively included (135 patients, 164 operated ears) from a large database. Patients underwent 1.5 T (128 ears) or 3 T MRI (36 ears), with non-echo planar DWI, T1 and T2 acquisitions. Two radiologists independently reassessed the images. Definitive surgical diagnosis was used as gold standard. Sensitivity, specificity and diagnostic odds ratio were evaluated.

RESULTS

According to surgical diagnosis a cholesteatoma was present in 124 of 164 ears, corresponding with a prevalence of 75%. Sensitivity and specificity were lower for 3 T compared to 1.5 T, irrespective of whether additional T1 and T2-weighted sequences were used or not. Diagnostic odds ratios were higher for 1.5 T (34 and 12 for reader 1 and 2, respectively) compared to 3 T (3 and 4 for reader 1 and 2, respectively). Adding T1 and T2 sequences lowers sensitivity but increases specificity.

CONCLUSION

Non-epi DWI for the detection of residual/recurrent cholesteatoma is preferably performed on 1.5 T scanners over 3 T. The use of additional sequences regarding detection of cholesteatoma is debatable as it lowers sensitivity but increases specificity. However, these sequences may also be of use in diagnosing complications and planning surgical procedures in some hospitals.

Unexpected death after occipital condylar fracture

We present a rare fatal complication of an occipital condylar fracture. The patient was initially neurologically intact, but showed secondary clinical deterioration. Imaging revealed extensive extra-axial hemorrhage at the craniocervical junction and an acute obstructive hydrocephalus. MR imaging demonstrated a T2 hyperintens signal in both the lower brainstem and upper cervical spinal cord, likely caused by the extra-axial hemorrhage. As prognosis was estimated infaust, supportive treatment was discontinued and the patient died soon thereafter. This case report illustrates a rare, delayed complication and unexpected death in a patient having sustained an occipital condylar fracture.

Dual-Energy CT in Head and Neck Imaging

PURPOSE OF REVIEW

To explain the technique of Dual-energy CT (DECT) and highlight its applications and advantages in head and neck radiology.

RECENT FINDINGS

Using DECT, additional datasets can be created next to conventional images. In head and neck radiology, three material decomposition algorithms can be used for improved lesion detection and delineation of the tumor. Iodine concentration measurements can aid in differentiating malignant from nonmalignant lymph nodes and benign posttreatment changes from tumor recurrence. Virtual non-calcium images can be used for detection of bone marrow edema. Virtual mono-energetic imaging can be useful for improved iodine conspicuity at lower keV and for reduction of metallic artifacts and increase in signal-to-noise ratio at higher keV.

SUMMARY

DECT and its additional reconstructions can play an important role in head and neck cancer patients, from initial diagnosis and staging, to therapy planning, evaluation of treatment response and follow-up. Moreover, it can be helpful in imaging of infections and inflammation and parathyroid imaging as supplementary reconstructions can be obtained at lower or equal radiation dose compared with conventional single energy scanning.

An Exploratory Study to Detect Ménière's Disease in Conventional MRI Scans Using Radiomics

OBJECTIVE

The purpose of this exploratory study was to investigate whether a quantitative image analysis of the labyrinth in conventional magnetic resonance imaging (MRI) scans using a radiomics approach showed differences between patients with Ménière's disease (MD) and the control group.

MATERIALS AND METHODS

In this retrospective study, MRI scans of the affected labyrinths of 24 patients with MD were compared to the MRI scans of labyrinths of 29 patients with an idiopathic asymmetrical sensorineural hearing loss. The 1.5- and 3-T MRI scans had been previously made in a clinical setting between 2008 and 2015. 3D Slicer 4.4 was used to extract several substructures of the labyrinth. A quantitative analysis of the normalized radiomic image features was performed in Mathematica 10. The image features of the two groups were statistically compared.

RESULTS

For numerous image features, there was a statistically significant difference (p-value <0.05) between the MD group and the control group. The statistically significant differences in image features were localized in all the substructures of the labyrinth: 43 in the anterior semicircular canal, 10 in the vestibule, 22 in the cochlea, 12 in the posterior semicircular canal, 24 in the horizontal semicircular canal, 11 in the common crus, and 44 in the volume containing the reuniting duct. Furthermore, some figures contain vertical or horizontal bands (three or more statistically significant image features in the same image feature). Several bands were seen: 9 bands in the anterior semicircular canal, 1 band in the vestibule, 3 bands in the cochlea, 0 bands in the posterior semicircular canal, 5 bands in the horizontal semicircular canal, 3 bands in the common crus, and 10 bands in the volume containing the reuniting duct.

CONCLUSION

In this exploratory study, several differences were found in image features between the MD group and the control group by using a quantitative radiomics approach on high resolution T2-weighted MRI scans of the labyrinth. Further research should be aimed at validating these results and translating them in a potential clinical diagnostic method to detect MD in MRI scans.

Association between eye position on brain scan and hospital mortality in acute intracerebral hemorrhage

BACKGROUND AND PURPOSE

Conjugate eye deviation (CED) and horizontal skew deviation are often seen in patients with intracerebral hemorrhage (ICH), but its prognostic significance is unclear. In this study, the association between brain scan assessed eye position and hospital mortality in patients with supratentorial ICH was tested.

METHODS

A retrospective analysis was performed in 316 patients with supratentorial ICH. Eye position was measured on first brain computed tomography or magnetic resonance imaging. Patients with CED, horizontal skew deviation or no deviation were distinguished. The association between eye position and hospital mortality was assessed using logistic regression analysis.

RESULTS

Conjugate eye deviation was present in 96 (30.4%), skew deviation in 44 (13.9%) and no deviation in 176 (55.7%) patients. In patients with CED, 81.3% had an eye position to the ipsilateral side of the hemorrhage. In univariable regression analysis, skew deviation was associated with mortality (odds ratio 3.10, 95% confidence interval 1.57-6.11; P = 0.001). In multivariable regression analysis, adjusting for age, ICH volume, intraventricular extension and Glasgow Coma Scale, eye position was not independently associated with mortality.

CONCLUSION

Horizontal skew eyes were found to be an unfavorable prognostic factor. However, this was not independent of other important predictors of ICH mortality and is most probably explained by its association with worse initial clinical presentation.

The role of dual energy CT in differentiating between brain haemorrhage and contrast medium after mechanical revascularisation in acute ischaemic stroke

OBJECTIVES

To assess the feasibility of dual energy computed tomography (DE-CT) in intra-arterially treated acute ischaemic stroke patients to discriminate between contrast extravasation and intracerebral haemorrhage.

METHODS

Thirty consecutive acute ischaemic stroke patients following intra-arterial treatment were examined with DE-CT. Simultaneous imaging at 80 kV and 140 kV was employed with calculation of mixed images. Virtual unenhanced non-contrast (VNC) images and iodine overlay maps (IOM) were calculated using a dedicated brain haemorrhage algorithm. Mixed images alone, as "conventional CT", and DE-CT interpretations were evaluated and compared with follow-up CT.

RESULTS

Eight patients were excluded owing to a lack of follow-up or loss of data. Mixed images showed intracerebral hyperdense areas in 19/22 patients. Both haemorrhage and residual contrast material were present in 1/22. IOM suggested contrast extravasation in 18/22 patients; in 16/18 patients this was confirmed at follow-up. The positive predictive value (PPV) of mixed imaging alone was 25 %, with a negative predictive value (NPV) of 91 % and accuracy of 63 %. The PPV for detection of haemorrhage with DE-CT was 100 %, with an NPV of 89 % and accuracy improved to 89 %.

CONCLUSIONS

Dual energy computed tomography improves accuracy and diagnostic confidence in early differentiation between intracranial haemorrhage and contrast medium extravasation in acute stroke patients following intra-arterial revascularisation.

KEY POINTS

• Contrast material and haemorrhage have similar density on conventional 120-kV CT. • Contrast material hinders interpretation of CT in stroke patients after recanalisation. • Iodine and haemorrhage have different attenuation at lower kVs. • Dual energy CT improves accuracy in early differentiation of haemorrhage and contrast extravasation. • Early differentiation between iodine and haemorrhage helps to initiate therapy promptly.

The diagnostic accuracy of non-echo-planar diffusion-weighted imaging in the detection of residual and/or recurrent cholesteatoma of the temporal bone

BACKGROUND AND PURPOSE

Non-EPI DWI is a promising alternative to second-look surgery for the detection of residual and/or recurrent cholesteatoma. We evaluated the diagnostic accuracy, expressed as a positive predictive value, of MR imaging for the detection of residual and/or recurrent cholesteatoma in our hospital.

MATERIALS AND METHODS

Fifty-six MR imaging studies were performed from 2005 to 2010 in patients having previously undergone surgery for cholesteatoma. Pre- and postgadolinium T1-weighted, T2-weighted, and non-EPI DWI sequences were performed and correlated with clinical and intraoperative findings. Twenty-seven patients underwent second-look surgery; 7 were under close clinical follow-up. Twenty-two patients without evidence of cholesteatoma were under regular follow-up (range, 14-44 months).

RESULTS

Non-EPI DWI sequences showed increased DW signal intensity in 36 patients. Of those, 27 had second-look surgery, confirming cholesteatoma in 25 patients; in 1 patient, an empyema was diagnosed, and in the other patient, no cholesteatoma was found at surgery. In 2 patients who had not undergone surgery, increased DW signal intensity was accompanied by hyperintense signal intensity on T1-weighted images, consistent with transplanted fat in the postoperative cavity. The positive predictive value for detection of cholesteatoma was 93% (25/27).

CONCLUSIONS

Residual and/or recurrent cholesteatomas after primary cholesteatoma surgery can be accurately detected by increased DW signal intensity on non-EPI DWI. However, DWI without conventional sequences increased the risk of misdiagnosis in our patient setting because transplanted fat within the postoperative cavity may show increased DW signal intensity.

Intraoperative neurophysiological assessment of disabling symptoms in DBS surgery

INTRODUCTION

Neurophysiological assessment can provide quantitative measures for the selected motor signs that have been targeted for surgery and may be helpful in predicting the therapeutic effects of deep brain stimulation (DBS) on pathological tremor, motor performance, and rigidity.

OBJECTIVE

To present a survey and demonstrate the contribution of neurophysiological assessment of side effects and effects on disabling motor symptoms at various steps of DBS surgery, and to confirm its role for optimal target localization, as an adjuvant to anatomic imaging.

MATERIAL AND METHODS

The data result from 192 nuclei in 118 procedures on patients with Parkinson's disease (84), essential tremor (24), Hallenvorder Spatz dystonia (4), multiple sclerosis (4), and Holmes tremor (2). The intraoperative neurophysiological monitoring (IOM) protocol consists of semimicroelectrode recording (for subthalamic nuclei), whereas accelerotransducers and spectral analysis allow assessment of tremor, finger tapping (FT), diadochokinesis (DDK), and determination of the distance between DBS electrodes and internal capsule (IC). Rigidity is assessed by surface EMG recordings in combination with a goniometer.

RESULTS

The determination of the functional distance between the DBS electrode and the IC is based on the activation functions of axons in the IC. We show the high sensitivity of accelerometers for tremor over a large part of the body, the relationship between clinical scores and spectral frequencies of FT and DDK. Parkinsonian rigidity can be assessed from surface EMG (sEMG) by means of a balance coefficient, which can detect negative rigidity, for low unified Parkinson's disease rating scale (UPDRS) scores (0-2) and quantified EMG when negative rigidity is excluded.

CONCLUSION

Accelerometer and sEMG recording have shown their value for intraoperative assessment of disabling motor symptoms and side effects during surgery, to optimize the target position electrodes for DBS. The combination with contemporary signal analyzing techniques permit intraoperative monitoring without a significant delay. IONM improves sensitivity and adds objective neurophysiological data.

Improved neuromonitoring during spinal surgery using double-train transcranial electrical stimulation

Motor evoked potentials (MEPs) evoked by transcranial electrical stimulation (TES) have become an important technique for monitoring spinal cord function intra-operatively, but can fail in some patients. A new technique of double-train stimulation is described. A multipulse transcranial electrical stimulus is preceded by a preconditioning pulse train that leads to larger MEP responses. An MEP monitoring system was adapted for double-train transcranial stimulation (DTS). MEP responses from 160 anterior tibial muscles obtained by double-train stimulation were analysed. All patients received propofol/remifentanil/O2/N2O anaesthesia. Fifty-two (83%) out of 63 single-train tibial MEPs with response amplitudes below 100 microV were magnified to over 100 microV, with an inter-train (inter-stimulus) interval ITI = 10-35 ms. These 63 amplitudes were magnified by an overall logarithmic mean factor of 15.5. For 97 MEPs with amplitudes above 100 microV, the logarithmic mean facilitation factor was 2.4. It was concluded that double-train TES stimulation can markedly facilitate responses to a single stimulus train (STS). The facilitation appears to be most effective when the responses to STS would otherwise be small or absent. This preconditioning stimulation technique is therefore useful when an STS leads to responses that are too small for effective monitoring.