Prediction of Bone Marrow Biopsy Results From MRI in Multiple Myeloma Patients Using Deep Learning and Radiomics.

OBJECTIVES: In multiple myeloma and its precursor stages, plasma cell infiltration (PCI) and cytogenetic aberrations are important for staging, risk stratification, and response assessment. However, invasive bone marrow (BM) biopsies cannot be performed frequently and multifocally to assess the spatially heterogenous tumor tissue. Therefore, the goal of this study was to establish an automated framework to predict local BM biopsy results from magnetic resonance imaging (MRI). MATERIALS AND METHODS: This retrospective multicentric study used data from center 1 for algorithm training and internal testing, and data from center 2 to 8 for external testing. An nnU-Net was trained for automated segmentation of pelvic BM from T1-weighted whole-body MRI. Radiomics features were extracted from these segmentations, and random forest models were trained to predict PCI and the presence or absence of cytogenetic aberrations. Pearson correlation coefficient and the area under the receiver operating characteristic were used to evaluate the prediction performance for PCI and cytogenetic aberrations, respectively. RESULTS: A total of 672 MRIs from 512 patients (median age, 61 years; interquartile range, 53-67 years; 307 men) from 8 centers and 370 corresponding BM biopsies were included. The predicted PCI from the best model was significantly correlated ( P ≤ 0.01) to the actual PCI from biopsy in all internal and external test sets (internal test set: r = 0.71 [0.51, 0.83]; center 2, high-quality test set: r = 0.45 [0.12, 0.69]; center 2, other test set: r = 0.30 [0.07, 0.49]; multicenter test set: r = 0.57 [0.30, 0.76]). The areas under the receiver operating characteristic of the prediction models for the different cytogenetic aberrations ranged from 0.57 to 0.76 for the internal test set, but no model generalized well to all 3 external test sets. CONCLUSIONS: The automated image analysis framework established in this study allows for noninvasive prediction of a surrogate parameter for PCI, which is significantly correlated to the actual PCI from BM biopsy.

Mechanical thrombectomy for acute ischemic stroke in COVID-19 patients: multicenter experience in 111 cases.

BACKGROUND: Data on the frequency and outcome of mechanical thrombectomy (MT) for large vessel occlusion (LVO) in patients with COVID-19 is limited. Addressing this subject, we report our multicenter experience. METHODS: A retrospective cohort study was performed of consecutive acute stroke patients with COVID-19 infection treated with MT at 26 tertiary care centers between January 2020 and November 2021. Baseline demographics, angiographic outcome and clinical outcome evaluated by the modified Rankin Scale (mRS) at discharge and 90 days were noted. RESULTS: We identified 111 out of 11 365 (1%) patients with acute or subsided COVID-19 infection who underwent MT due to LVO. Cardioembolic events were the most common etiology for LVO (38.7%). Median baseline National Institutes of Health Stroke Scale score and Alberta Stroke Program Early CT Score were 16 (IQR 11.5-20) and 9 (IQR 7-10), respectively. Successful reperfusion (mTICI ≥2b) was achieved in 97/111 (87.4%) patients and 46/111 (41.4%) patients were reperfused completely. The procedure-related complication rate was 12.6% (14/111). Functional independence was achieved in 20/108 (18.5%) patients at discharge and 14/66 (21.2%) at 90 days follow-up. The in-hospital mortality rate was 30.6% (33/108). In the subgroup analysis, patients with severe acute COVID-19 infection requiring intubation had a mortality rate twice as high as patients with mild or moderate acute COVID-19 infection. Acute respiratory failure requiring ventilation and time interval from symptom onset to groin puncture were independent predictors for an unfavorable outcome in a logistic regression analysis. CONCLUSION: Our study showed a poor clinical outcome and high mortality, especially in patients with severe acute COVID-19 infection undergoing MT due to LVO.

Contrast Neurotoxicity and its Association with Symptomatic Intracranial Hemorrhage After Mechanical Thrombectomy.

PURPOSE: Despite improved techniques and sophisticated postinterventional care, symptomatic intracranial hemorrhage (sICH) remains the most feared complication of mechanical thrombectomy (MT). Based on peri-interventional parameters, we aimed to discover which patients have a higher risk of sICH. METHODS: From March 2017 until March 2020 consecutive patients with acute ischemic stroke (AIS) and confirmed large-vessel occlusion who underwent MT were analyzed retrospectively. Demographic, clinical, and radiological variables and parameters specific to thrombectomy were reviewed. A univariate analysis was performed and statistically significant variables were included in a logistic regression model to identify independent factors predictive of sICH. RESULTS: A total of 236 patients with confirmed large-vessel occlusion were included and 22 (9.3%) had sICH. Univariate predictors of sICH included diabetes mellitus, glucose > 11.1 mmol/L, creatinine clearance (CrCl) ≤ 30 ml/min/1.73, ASPECTS indicating pretreatment infarct size, acute internal carotid artery (ICA) occlusion, stent implantation, tirofiban use, time from symptom onset to groin puncture > 4.5 h and high contrast medium consumption. In the adjusted analysis, ASPECTS < 6 (OR 3.673, p = 0.041), and amount of contrast injected ≥ 140 ml (OR 5.412, p = 0.003) were independent predictors of sICH, but not any more baseline glucose > 11.1 mmol/L (OR 1.467, p = 0.584), CrCl ≤ 30 ml/min/1.73 (OR 4.177, p = 0.069), acute ICA occlusion (OR 2.079, p = 0.181), stent implantation (OR 0.465, p = 0.512), tirofiban use (OR 5.164, p = 0.167), and time from onset-to-groin puncture (OR 1.453, p = 0.514). CONCLUSION: The amount of contrast medium used is a modifiable factor associated with sICH. This association is novel and may be related to the neurotoxicity of the contrast medium disrupting the blood-brain barrier.

Ischemic stroke secondary to self-inflicted carotid sinus massage: a case report.

BACKGROUND: The risk of stroke after carotid sinus massage is greater if there is preexisting carotid stenosis or carotid plaques. We present the case of a patient with underlying 40% carotid stenosis, who developed a watershed stroke after a self-neck massage in our stroke unit. We show a well-documented case with magnetic resonance images before and after the neck massage. We report a case of a watershed brain infarct after a self-massage of the carotid sinus, with preexisting carotid artery stenosis. Neck massage continues to be a significant cause of stroke and should therefore not be performed by patients. Clinicians must be aware of the implications of a carotid sinus massage in both the outpatient and inpatient settings. CASE PRESENTATION: We admitted a 58-year-old white male patient, with no relevant medical history, to our department with a brain stem infarct. During his stay at our stroke unit, the patient performed a self-neck massage with consecutive bradycardia and asystole, resulting in left-side hemiparesis. The underlying cause of the hemodynamic stroke is believed to be secondary to this intensive neck massage performed by the patient. The patient also suffered from unknown right internal carotid artery stenosis. CONCLUSION: Clinicians and patients must be aware that neck massage can lead to ischemic stroke. We postulate that repetitive impaired cardiac output can lead to a hemodynamic (watershed-type) stroke.

Characteristics and Unexpected COVID-19 Diagnoses in Resuscitation Room Patients during the COVID-19 Outbreak-A Retrospective Case Series.

INTRODUCTION: Emergency department (ED) triage regarding infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is challenging. During the coronavirus disease 2019 (COVID-19) outbreak in Germany, the diagnostic outcomes of critically ill patients admitted to the resuscitation room in the ED of our academic 754-bed hospital should be analyzed. METHODS: All resuscitation room patients between March 1st and April 15th 2020 were included in this retrospective study. Every patient with suspicion of SARS-CoV-2 infection received a pharyngeal swab for real-time polymerase chain reaction (rt-PCR), divided in the clinical subgroups of "highly suspicious for COVID-19" and "COVID-19 as differential diagnosis." All respiratory and infectious symptoms were included as at least "differential diagnosis" as an expanded suspicion strategy. RESULTS: Ninety-five patients were included (trauma n = 14, critically ill n = 81). Of 3 highly suspicious patients, 2 had rt-PCR positive pharyngeal swabs. In 39 patients, COVID-19 was defined as differential diagnosis, and 3 were positive for SARS-CoV-2. Of them, pharyngeal swabs were positive in 1 case, while in 2 cases, only tracheal fluid was rt-PCR positive while the pharyngeal swabs were negative. In one of these 2 cases, chest computed tomography (CT) was also negative for ground-glass opacities but showed a pulmonary abscess and pulmonary embolism. CONCLUSION: We recommend an expanded suspicion strategy for COVID-19 due to unexpected diagnostic outcomes. Personal protective equipment should be used in every resuscitation room operation due to unexpected cases and initial knowledge gaps. Furthermore, tracheal fluid should be tested for SARS-CoV-2 in every intubated patient due to cases with negative pharyngeal swabs and negative chest CT.

Higher sensitivity for traumatic cerebral microbleeds at 7 T ultra-high field MRI: is it clinically significant for the acute state of the patients and later quality of life?

BACKGROUND: The present study evaluates the possible prognostic benefits of 7 T susceptibility weighted imaging (SWI) of traumatic cerebral microbleeds (TMBs) over 3 T SWI to predict the acute clinical state and subjective impairments, including health-related quality of life (HRQOL), after closed head injury (CHI). METHODS: The study group comprised 10 participants with known TMBs All subjects underwent 3 T magnetic resonance imaging (MRI) and 7 T MRI, respectively. Location and count of TMBs were independently evaluated by two neuroradiologists. The initial Glasgow Coma Scale (GCS), the duration of coma and further clinical data were taken from the patients records. HRQOL was assessed by means of a questionnaire. Memory complaints and neurological symptoms were inquired at the time of the MRI examinations. RESULTS: SWI revealed a total of 485 TMBs at 3 T, 584 TMBs at 7 T with similar spatial resolution, and 684 TMBs at 7 T with a factor of 10 higher spatial resolution. The TMBs depicted by 7 T high-resolution SWI were correlated with the duration of coma (Spearman's rho of 0.77). The corresponding association with TMBs in 3 T MRI SWI showed a Spearman's rho of 0.71. The initial GCS score and TMBs correlated with a Spearman's rho of -0.35 at 3 T SWI MRI and a rho of -0.33 at 7 T high-resolution SWI, respectively. The physical aspect of HRQOL correlated substantially with the count of TMBs (rho = 0.44 for 3 T SWI and rho = 0.35 for both 7 T SWI sequences, respectively). CONCLUSIONS: The number of TMBs showed a substantial association with indicators of the acute clinical state and chronic neurobehavioral parameters after CHI, but there was no additional advantage of 7 T MRI. These preliminary findings warrant a larger prospective study for the future.

Influence of orbital morphology on proptosis reduction and ocular motility after decompression surgery in patients with Graves' orbitopathy.

PURPOSE: Orbital decompression surgery is performed in patients with Graves' orbitopathy to treat dysthyroid optical neuropathy (DON) and reduce disfiguring proptosis. The intended proptosis reduction can deviate from the postoperative result and changes of motility with consecutive diplopia can occur. We performed a retrospective study to identify anatomical factors in computed tomography (CT), which influence the surgical effect and postoperative ocular motility and diplopia. METHODS: Pre- and postoperative CT-scans of 125 eyes of 68 patients, who mainly underwent a balanced orbital decompression for disfiguring proptosis (≥18mm Hertel Index), have been analyzed. Proptosis, ductions, misalignment and diplopia were assessed before and after surgery. Medial and lateral orbital wall length, conus angle, depth of ethmoidal sinus, orbital surface, length of medial and orbital defect, depth of tissue prolapse and horizontal muscle diameters were analyzed in CT scans before and after surgery. With linear regression and multivariate analyses these parameters have been correlated with postoperative proptosis, abduction deficit, deviation and binocular single vision (BSV). RESULTS: Proptosis could be reduced by 5.3±2mm. Patients with <5mm proptosis reduction had significantly less often new onset of diplopia compared to patients with >5mm reduction (13% vs. 56%, p = 0.02). Multiple linear regression showed a significant correlation between tissue prolapse and depth of the ethmoidal sinus as well as age (p<0.001, r = 0.71). Proptosis reduction could not be predicted by tissue prolapse, defect length or depth of ethmoidal sinus. The abduction deficit correlated significantly with tissue prolapse and orbital surface area (p<0.001, r = 0.37) but not with the horizontal muscle diameter. CONCLUSION: We were able to show that orbital morphology influences the outcome of balanced orbital decompression surgery in terms of proptosis reduction and motility. However, the rather low coefficients of correlation show that the surgical outcome cannot be predicted with simple CT measurements, although risk factors for postoperative abduction deficit could be found. Therefore, preoperative planning should consider especially the orbital surface area and depth of ethmoidal sinus. Patients should be informed about the higher risk of diplopia with higher proptosis reduction.

Radiation exposure during CT-guided biopsies: recent CT machines provide markedly lower doses.

OBJECTIVES: To examine radiation dose levels of CT-guided interventional procedures of chest, abdomen, spine and extremities on different CT-scanner generations at a large multicentre institute. MATERIALS AND METHODS: 1,219 CT-guided interventional biopsies of different organ regions ((A) abdomen (n=516), (B) chest (n=528), (C) spine (n=134) and (D) extremities (n=41)) on different CT-scanners ((I) SOMATOM-Definition-AS+, (II) Volume-Zoom, (III) Emotion6) were included from 2013-2016. Important CT-parameters and standard dose-descriptors were retrospectively examined. Additionally, effective dose and organ doses were calculated using Monte-Carlo simulation, following ICRP103. RESULTS: Overall, radiation doses for CT interventions are highly dependent on CT-scanner generation: the newer the CT scanner, the lower the radiation dose imparted to patients. Mean effective doses for each of four procedures on available scanners are: (A) (I) 9.3mSv versus (II) 13.9mSv (B) (I) 7.3mSv versus (III) 11.4mSv (C) (I) 6.3mSv versus (II) 7.4mSv (D) (I) 4.3mSv versus (II) 10.8mSv. Standard dose descriptors [standard deviation (SD); CT dose indexvol (CTDIvol); dose-length product (DLPbody); size-specific dose estimate (SSDE)] were also compared. CONCLUSION: Effective dose, organ doses and SSDE for various CT-guided interventional biopsies on different CT-scanner generations following recommendations of the ICRP103 are provided. New CT-scanner generations involve markedly lower radiation doses versus older devices. KEY POINTS: • Effective dose, organ dose and SSDE are provided for CT-guided interventional examinations. • These data allow identifying organs at risk of higher radiation dose. • Detailed knowledge of radiation dose may contribute to a better individual risk-stratification. • New CT-scanner generations involve markedly lower radiation doses compared to older devices.

Verification of organ doses calculated by a dose monitoring software tool based on Monte Carlo Simulation in thoracic CT protocols.

Background The importance of monitoring of the radiation dose received by the human body during computed tomography (CT) examinations is not negligible. Several dose-monitoring software tools emerged in order to monitor and control dose distribution during CT examinations. Some software tools incorporate Monte Carlo Simulation (MCS) and allow calculation of effective dose and organ dose apart from standard dose descriptors. Purpose To verify the results of a dose-monitoring software tool based on MCS in assessment of effective and organ doses in thoracic CT protocols. Material and Methods Phantom measurements were performed with thermoluminescent dosimeters (TLD LiF:Mg,Ti) using two different thoracic CT protocols of the clinical routine: (I) standard CT thorax (CTT); and (II) CTT with high-pitch mode, P = 3.2. Radiation doses estimated with MCS and measured with TLDs were compared. Results Inter-modality comparison showed an excellent correlation between MCS-simulated and TLD-measured doses ((I) after localizer correction r = 0.81; (II) r = 0.87). The following effective and organ doses were determined: (I) (a) effective dose = MCS 1.2 mSv, TLD 1.3 mSv; (b) thyroid gland = MCS 2.8 mGy, TLD 2.5 mGy; (c) thymus = MCS 3.1 mGy, TLD 2.5 mGy; (d) bone marrow = MCS 0.8 mGy, TLD 0.9 mGy; (e) breast = MCS 2.5 mGy, TLD 2.2 mGy; (f) lung = MCS 2.8 mGy, TLD 2.7 mGy; (II) (a) effective dose = MCS 0.6 mSv, TLD 0.7 mSv; (b) thyroid gland = MCS 1.4 mGy, TLD 1.8 mGy; (c) thymus = MCS 1.4 mGy, TLD 1.8 mGy; (d) bone marrow = MCS 0.4 mGy, TLD 0.5 mGy; (e) breast = MCS 1.1 mGy, TLD 1.1 mGy; (f) lung = MCS 1.2 mGy, TLD 1.3 mGy. Conclusion Overall, in thoracic CT protocols, organ doses simulated by the dose-monitoring software tool were coherent to those measured by TLDs. Despite some challenges, the dose-monitoring software was capable of an accurate dose calculation.

[Extracranial schwannomas of the Head and Neck: Clinical -approach based on 20 cases]. / Extrakranielle Schwannome im Kopf-Hals-Bereich: Klinische Implikationen anhand von 20 Fällen.

Background Schwannomas are rare benign tumors originating from the perineural cells forming the myelin layer in the peripheral nervous system (PNS). While well established therapeutic concepts exist for intracranial schwannomas, there is a lack of consistent clinical standards for extracranial schwannomas. Method This retrospective study describes the clinical pathway of 20 patients with histologically proven extracranial schwannomas of the head and neck. The diagnostic and therapeutic strategies for schwannomas are discussed with special emphasis on localization and functional outcome. Results Extracranial schwannomas of the head and neck region mostly originated from the facial nerve (n = 4), vagal nerve (n = 4) or sympathetic chain (n = 3). Most common symptoms were swelling (n = 12) and pain (n = 3). Preoperative imaging included MRI (n = 13), ultrasound (n = 12) and CT (n = 3). Surgical intervention was performed in 18 cases (n = 14 complete extirpation, n = 3 partial extirpation, n = 1 unknown). Regarding completely extirpated schwannomas of motor nerves (n = 10) severing the nerve of origin was more often required in patients with a preexisting functional deficit (3 out of 4 = 75 %) than in patients without preexisting deficits (2 out of 6 = 33 %). Conclusion Representing rare tumors of the head and neck region mostly originating from the facial nerve, sympathetic chain or caudal cranial nerves extracranial schwannomas require a systematic diagnostic and therapeutic approach. Postoperative functional deficits after complete extirpation must especially be anticipated in patients with a preexisting functional deficit.

Efficacy of Lens Protection Systems: Dependency on Different Cranial CT Scans in The Acute Stroke Setting.

To evaluate the dose-reduction potential with different lens protectors for patients undergoing cranial computed tomography (CT) scans. Eye lens dose was assessed in vitro (α-Al2O3:C thermoluminescence dosemeters) using an Alderson-Rando phantom® in cranial CT protocols at different CT scanners (SOMATOM-Definition-AS+®(CT1) and SOMATOM-Definition-Flash® (CT2)) using two different lens-protection systems (Somatex® (SOM) and Medical Imaging Systems® (MIS)). Summarised percentage of the transmitted photons: (1) CT1 (a) unenhanced CT (nCT) with gantry angulation: SOM = 103%, MIS = 111%; (2) CT2 (a) nCT without gantry angulation: SOM = 81%, MIS = 91%; (b) CT angiography (CTA) with automatic dose-modulation technique: SOM = 39%, MIS = 74%; (c) CTA without dose-modulation technique: SOM = 22%, MIS = 48%; (d) CT perfusion: SOM = 44%, MIS = 69%. SOM showed a higher dose-reduction potential than MIS maintaining equal image quality. Lens-protection systems are most effective in CTA protocols without dose-reduction techniques. Lens-protection systems lower the average eye lens dose during CT scans up to 1/3 (MIS) and 2/3 (SOM), respectively, if the eye lens is exposed to the direct beam of radiation. Considering both the CT protocol and the material of lens protectors, they seem to be mandatory for reducing the radiation exposure of the eye lens.

Can we now dispense with DSA in the evaluation of aneurysm occlusion even in the most crucial first follow-up after endovascular treatment?

OBJECTIVES: Catheter angiography (DSA) as gold standard for the evaluation of aneurysmal occlusion after coiling has now been largely replaced by MRI or CTA in long term observations. However, the first year after treatment is crucial because most recurrences occur in this time. Until now no guidelines exist concerning the imaging modality to adopt in this period. Aim of the study was to determine whether DSA could also be omitted in the first follow-up examination after coiling due to MRI results. PATIENTS AND METHODS: 489 consecutive half-year follow-up examinations consisting of DSA, CE-MRA and TOF-MRA at 1.5 or 3T were reviewed retrospectively. Visualization of residual or recurrent aneurysms in both MRA-techniques was compared to DSA by two experienced readers. RESULTS: Remnants/recurrences could be visualized in at least one of the three techniques in 190 (38.9%) aneurysms. Remnants/recurrences requiring retreatment (n=52) were detectable with at least one of the two MRI-techniques. In three cases (0.6%) remnants/recurrences were only visible on DSA but neither on CE-MRA nor on TOF-MRA. However, they were small (<2mm) and therapy concept did not change. In one case (0.2%) they were only visible on the CE-MRA and TOF-MRA but not on the DSA, in five cases (1%) visible on DSA and TOF-MRA but not on the CE-MRA and in four cases (0.8%) not visible on the TOF-MRA but on both of the other imaging modalities. CONCLUSION: The combination of CE-MRA und TOF-MRA is also an appropriate alternative to DSA concerning the evaluation of residual or recurrent aneurysms in the crucial first follow-up.

Clinical evaluation of a dose monitoring software tool based on Monte Carlo Simulation in assessment of eye lens doses for cranial CT scans.

INTRODUCTION: The aim of this study was to verify the results of a dose monitoring software tool based on Monte Carlo Simulation (MCS) in assessment of eye lens doses for cranial CT scans. METHODS: In cooperation with the Federal Office for Radiation Protection (Neuherberg, Germany), phantom measurements were performed with thermoluminescence dosimeters (TLD LiF:Mg,Ti) using cranial CT protocols: (I) CT angiography; (II) unenhanced, cranial CT scans with gantry angulation at a single and (III) without gantry angulation at a dual source CT scanner. Eye lens doses calculated by the dose monitoring tool based on MCS and assessed with TLDs were compared. RESULTS: Eye lens doses are summarized as follows: (I) CT angiography (a) MCS 7 mSv, (b) TLD 5 mSv; (II) unenhanced, cranial CT scan with gantry angulation, (c) MCS 45 mSv, (d) TLD 5 mSv; (III) unenhanced, cranial CT scan without gantry angulation (e) MCS 38 mSv, (f) TLD 35 mSv. Intermodality comparison shows an inaccurate calculation of eye lens doses in unenhanced cranial CT protocols at the single source CT scanner due to the disregard of gantry angulation. On the contrary, the dose monitoring tool showed an accurate calculation of eye lens doses at the dual source CT scanner without gantry angulation and for CT angiography examinations. CONCLUSION: The dose monitoring software tool based on MCS gave accurate estimates of eye lens doses in cranial CT protocols. However, knowledge of protocol and software specific influences is crucial for correct assessment of eye lens doses in routine clinical use.

How Much Is the Dose Varying between Follow-Up CT-Examinations Performed on the Same Scanner with the Same Imaging Protocol?

PURPOSE: To investigate the dose variation between follow-up CT examinations, when a patient is examined several times on the same scanner with the identical scan protocol which comprised automated exposure control. MATERIAL AND METHODS: This retrospective study was approved by the local ethics committee. The volume computed tomography dose index (CTDIvol) and the dose-length-product (DLP) were recorded for 60 cancer patients (29 male, 31 female, mean age 60.1 years), who received 3 follow-up CT examinations each composed of a non-enhanced scan of the liver (LI-CT) and a contrast-enhanced scan of chest (CH-CT) and abdomen (AB-CT). Each examination was performed on the same scanner (Siemens Definition FLASH) equipped with automated exposure control (CARE Dose 4D and CARE KV) using the identical scan protocol. RESULTS: The median percentage difference in DLP between follow-up examinations was 9.6% for CH-CT, 10.3% for LI-CT, and 10.1% for AB-CT; the median percentage difference in CTDIvol 8.3% for CH-CT, 7.4% for LI-CT and 7.7% for AB-CT (p<0.0001 for all values). The maximum difference in DLP between follow-up examinations was 67.5% for CH-CT, 50.8% for LI-CT and 74.3% for AB-CT; the maximum difference in CTDIvol 62.9% for CH-CT, 47.2% for LI-CT, and 49% for AB-CT. CONCLUSION: A significant variance in the radiation dose occurs between follow-up CT examinations when the same CT scanner and the identical imaging protocol are used in combination with automated exposure control.

Dual-energy computed tomography for evaluation of pulmonary nodules with emphasis on metastatic lesions.

BACKGROUND: The contrast enhancement of pulmonary nodules is a differential diagnostic criterion which can be helpful in staging investigations. PURPOSE: To investigate the impact of dual-energy computed tomography (DECT) with regards to the evaluation of pulmonary nodules with emphasis on metastatic lesions. MATERIAL AND METHODS: DECT scans of the thorax were performed in 70 consecutive patients. Data of the lung were acquired in the arterial and in delayed venous phase. The virtual native and overlay image data based on arterial and delayed venous phase of these lesions were compared using CT density values (HU) within the nodule tested for statistical significance. RESULTS: A total of 156 pulmonary lesions ≥5 mm were identified on 70 DECT scans. There were no significant differences between the CT-value measurements in the virtual native images based on the arterial and delayed venous phase (27.9+/-3.9 HU vs.28.1+/-4.2 HU, P = 0.89) and between the CT-value measurements in the overlay images based on the arterial und delayed venous phase (35.5+/-6.8 HU vs. 36.6+/-5.0 HU, P = 0.75). Metastases of colorectal carcinoma (51.4+/-9.4 HU vs. 32.5+/-8.9 HU, P = 0.0001), malignant melanoma (56.1+/-6.4 HU vs. 34.2+/-1.6 HU, P = 0.0045), and thyroid cancer (53.5+/-15.5 HU vs. 15.7+/-4.2 HU, P = 0.001) showed a distinct wash-out, whereas metastases of lung cancer (23.1+/-6.3 HU vs. 58.6+/-4.8 HU, P = 0.001), salivary gland cancer (41.4+/-20.3 HU vs. 65.7+/-15.7 HU, P = 0.023), and sarcoma (56.2+/-7.4 HU vs. 90.2+/-3.4 HU, P = 0.001) had an increased enhancement in the delayed venous phase. CONCLUSION: The contrast enhancement behavior of pulmonary metastases can be evaluated with DECT and depends on the type of the primary malignant tumor.

Surgical management of intradural spinal cord tumors in children and young adults: A single-center experience with 50 patients.

BACKGROUND: Intradural spinal cord tumors (IDSCTs) in children and young adults are rare diseases. This present study is aimed to demonstrate our experience with a large series of children and young adults with IDSCT. METHODS: A total of 50 patients aged <20 years with IDSCT treated in our department between 1990 and 2010 were included in the study. Clinical, histological, and radiological findings, treatment strategies, and clinical outcome were retrospectively assessed. Depending on the relation to the spinal cord, IDSCT were dichotomized into intramedullary SCT (IMSCT) and extramedullary SCT (EMSCT). The functional outcome was evaluated with the Frankel score assessing the longest available follow-up period. RESULTS: Mean age was 10.3 years (range 6 months-19 years). IDSCT surgery was performed in 44 patients (88%). A common first symptom in patients with EMSCT was neck and back pain (41%), whereas monoparesis of arms (43%) were often seen in patients with IMSCT. The main duration of the symptoms was longer in patients with IMSCT. The postoperative functional outcome was generally comparable to the preoperative functional condition, while better for EMSCT (P < 0.01). The functional outcome at last follow-up correlated significantly with the preoperative Frankel score (P < 0.002). CONCLUSION: Due to the mostly mild impact of the surgery on the functional outcome, the surgical treatment of IDSCT in children and young patients can be uniquely advocated.

Management of traumatic spinal injuries in children and young adults.

PURPOSE: Spinal injuries are rarely seen in pediatric patients and therapeutic options are still poorly defined. The present study is aimed to present our experience with a rather large series of children and young adults suffering from traumatic spinal injury. PATIENTS AND METHODS: Between 1990 and 2010, 75 consecutive pediatric patients with spinal injuries were treated in our institution. Mean age was 15 years, ranging from 3 months to 21 years. Radiological findings, treatment strategies, and clinical outcome were evaluated retrospectively and compared with literature. Forty (53.3%) patients were treated conservatively and 35 patients (47%) surgically using anterior or posterior approaches. Subgroup analysis was performed depending on age groups, severity of neurological symptoms, and localization. RESULTS: Main trauma mechanisms were fall in 24 patients (38%) and motor vehicle accidents in 21 patients (28%). Complete neurological deficits were present in 17 individuals (23%) and incomplete in 36 patients (48%). Fractures were most frequently localized at the cervical region (56%) with predilection of the C 5/6 segment. Odontoid fractures were seen in 10 (13%) patients. Fractures of the lumbar and thoracic region were rare. Level of injury or clinical course did not differ between the subgroups (≤15 years versus >15 years). CONCLUSION: Nearly three fourths of all radiologically detected spinal injuries are located at the cervical spine. Complete neurological deficits after trauma was associated with a poor outcome, in particular for patients with injuries of the upper cervical spine. The use of autologous bone graft was associated with favorable long-term results and should be considered as the material of first choice for vertebral body and disc replacement.

Diffuse axonal injury at ultra-high field MRI.

OBJECTIVE: Diffuse axonal injury (DAI) is a specific type of traumatic brain injury caused by shearing forces leading to widespread tearing of axons and small vessels. Traumatic microbleeds (TMBs) are regarded as a radiological marker for DAI. This study aims to compare DAI-associated TMBs at 3 Tesla (T) and 7 T susceptibility weighted imaging (SWI) to evaluate possible diagnostic benefits of ultra-high field (UHF) MRI. MATERIAL AND METHODS: 10 study participants (4 male, 6 female, age range 20-74 years) with known DAI were included. All MR exams were performed with a 3 T MR system (Magnetom Skyra) and a 7 T MR research system (Magnetom 7 T, Siemens AG, Healthcare Sector, Erlangen, Germany) each in combination with a 32-channel-receive coil. The average time interval between trauma and imaging was 22 months. Location and count of TMBs were independently evaluated by two neuroradiologists on 3 T and 7 T SWI images with similar and additionally increased spatial resolution at 7 T. Inter- and intraobserver reliability was assessed using the interclass correlation coefficient (ICC). Count and diameter of TMB were evaluated with Wilcoxon signed rank test. RESULTS: Susceptibility weighted imaging revealed a total of 485 TMBs (range 1-190, median 25) at 3 T, 584 TMBs (plus 20%, range 1-262, median 30.5) at 7 T with similar spatial resolution, and 684 TMBs (plus 41%, range 1-288, median 39.5) at 7 T with 10-times higher spatial resolution. Hemorrhagic DAI appeared significantly larger at 7 T compared to 3 T (p = 0.005). Inter- and intraobserver correlation regarding the counted TMB was high and almost equal 3 T and 7 T. CONCLUSION: 7 T SWI improves the depiction of small hemorrhagic DAI compared to 3 T and may be supplementary to lower field strengths for diagnostic in inconclusive or medicolegal cases.