Diffusion-weighted Imaging Patterns Research Articles

The correlation of embolic sources with infarct pattern in patients with embolic stroke (P6-5.015)

<h3>Objective:</h3> To exclusively identify potential embolic sources (PES) applying transesophageal echocardiography (TEE) and correlate them with topographic diffusion-weighted imaging patterns (DWI) in patients with embolic stroke. <h3>Background:</h3> Embolic stroke of undetermined source (ESUS) has been reported to show a relatively high stroke recurrence rate. Thus, early identification of potential embolic source (PES) is critical for acute treatment and/or secondary prevention. If acute topographic diffusion-weighted imaging patterns (DWI) would correlate with specific PES, it may prove very useful. <h3>Design/Methods:</h3> A total of 992 consecutive patients with embolic stroke were studied. Apart from the known embolic group (n=560), we focused on the unknown embolic group (n=366) that was defined as no arrhythmia during the first day from admission and no PES after general examination. DWI were classified based on the arterial supply. Age and sex adjusted odds ratio (OR) of each DWI for the different PESs were calculated. Middle cerebral arteries (MCA) were divided into 4 segments, i.e., M1~M4. Moreover, M2 segments were subdivided into superior and inferior branches. <h3>Results:</h3> 366 patients consisted of 168 with paroxysmal atrial fibrillation (pAf), 82 with paradoxical embolism (PxE), 71 with aorto-embolism (AoE), leaving 39 patients undetermined. The DWIs of internal carotid artery (OR: 15.0, p=0.0027), M1 (4.2, p=0.0003), inferior M2 (3.6, p=0.04) and multiple cortical branches (MCB) (21.6, p&lt;0.0001) were significantly associated with pAf. Striatocapsular infarction (SCI) (15.1, p&lt;0.0001) was significantly associated with PxE and multiple small scattered infarcts (8.6, p&lt;0.0001) with AoE. <h3>Conclusions:</h3> The correlations of DWI with different PESs have their distinctive characteristics. The DWI of inferior M2 as well as large infarcts and multiple cortical infarcts were associated with pAf, that of SCI with PxE and MSS with AoE. The characteristic histopathology and hydrodynamic mechanism of thrombi may determine DWI. <b>Disclosure:</b> Yasumasa Yamamoto has nothing to disclose.

Cancer-related cryptogenic stroke involving the bilateral anterior and the posterior circulations: Diagnostic value of clinical and imaging characteristics.

This study analyzed the clinical and imaging characteristics of patients with cancer-related cryptogenic stroke (CCS) involving the bilateral anterior and the posterior circulations (three circulations) and evaluate the diagnostic value of clinical and imaging features for patients with cryptogenic stroke involving three circulations (CST). Of the 12,580 patients with acute ischemic stroke, 148 patients with CST from May 2017 to November 2021 were divided into the cancer group (n = 81) and the non-cancer group (n = 67). Cardiovascular risk factors, diffusion-weighted imaging patterns of cryptogenic stroke, blood routine, coagulation routine, and biochemical routine were compared between the two groups. Multivariable logistic regression and receiver operating characteristic (ROC) curve analysis were used to determine associations between the two groups. Compared with the non-cancer group, the cancer group exhibited higher D-dimer levels (P < 0.001), fibrin degradation product (FDP, P < 0.001), international normalized ratio (INR, P = 0.014), neutrophil to lymphocyte ratio (NLR, P < 0.001), platelets to lymphocyte ratio (PLR, P = 0.001), activated partial thromboplastin time (APTT, P = 0.039), more frequent multiple lesions in three circulations (P < 0.001) and lower lymphocytes (P < 0.001), red blood cells (P < 0.001), and thrombin time (TT, P = 0.034). Furthermore, D-dimer [area under the curve (AUC) = 0.915, P < 0.001)], FDP (AUC = 0.923, P < 0.001), INR (AUC = 0.617, P = 0.014), NLR (AUC = 0.700, P < 0.001), PLR (AUC = 0.658, P = 0.001), and multiple lesions in three circulations (AUC = 0.786, P < 0.001) had potential diagnostic value in cryptogenic stroke. When combining these 6 parameters, the predictive power was improved (AUC = 0.949, P < 0.001). Cryptogenic stroke involving three circulations with cancer has unique clinical features, and these potential diagnostic indicators could help patients identify CCS earlier.

Diffusion-weighted imaging as predictor of acute ischemic stroke etiology.

Topographic patterns may correlate with causes of ischemic stroke. To investigate the association between diffusion-weighted imaging (DWI) and Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification. We included 1019 ischemic stroke patients. DWI were classified as: i) negative; ii) DWI single lesion (cortico-subcortical, cortical, subcortical ≥20 mm, or subcortical <20 mm); iii) scattered lesions in one territory (small scattered lesions or confluent with additional lesions); and iv) multiple lesions (multiple unilateral anterior circulation [MAC], multiple posterior circulation [MPC], multiple bilateral anterior circulation [MBAC], and multiple anterior and posterior circulations [MAP]). There was a relationship between DWI patterns and TOAST classification (p<0.001). Large artery atherosclerosis was associated with small, scattered lesions in one vascular territory (Odds Ratio [OR] 4.22, 95% confidence interval [95%CI] 2.61-6.8), MPC (OR 3.52; 95%CI 1.54-8.03), and subcortical lesions <20 mm (OR 3.47; 95%CI 1.76-6.85). Cardioembolic strokes correlated with MAP (OR 4.3; 95%CI 1.64-11.2), cortico-subcortical lesions (OR 3.24; 95%CI 1.9-5.5) and negative DWI (OR 2.46; 95%CI 1.1-5.49). Cryptogenic strokes correlated with negative DWI (OR 4.1; 95%CI 1,84-8.69), cortical strokes (OR 3.3; 95%CI 1.25-8.8), MAP (OR 3.33; 95%CI 1.25-8.81) and subcortical lesion ≥20 mm (OR 2.44; 95%CI 1,04-5.73). Lacunar strokes correlated with subcortical lesions diameter <20 mm (OR 42.9; 95%CI 22.7-81.1) and negative DWI (OR 8.87; 95%CI 4.03-19.5). Finally, MBAC (OR 9.25; 95%CI 1.12-76.2), MAP (OR 5.54; 95%CI 1.94-15.1), and MPC (OR 3.61; 95%CI 1.5-8.7) correlated with stroke of other etiologies. A relationship exists between DWI and stroke subtype.

Differentiating Between an Atypical Hepatic Abscess and Tumor Metastasis Using Magnetic Resonance Imaging and Hepatobiliary Phase Imaging.

ObjectiveTo identify diffusion-weighted imaging (DWI) patterns and conspicuity discrepancies on hepatobiliary phase imaging (HBPI) to distinguish atypical hepatic abscesses from hepatic metastases.Materials and MethodsThis retrospective study recruited 31 patients with 43 atypical hepatic abscesses and 32 patients with 35 hepatic metastases who underwent gadobenate dimeglumine-enhanced magnetic resonance imaging. All lesions were confirmed by pathological or clinical diagnosis. For the qualitative and quantitative analyses, the signal intensity, DWI pattern, apparent diffusion coefficient, degree of perilesional edema, perilesional hyperemia, perilesional signal on HBPI, conspicuity, size discrepancy between sequences, contrast-to-noise ratio, signal-to-noise ratio, and relative enhancement ratio on dynamic phases were independently assessed by two radiologists. Significant findings for differentiating the two groups were identified via univariate and multivariate analyses with a nomogram for predicting atypical hepatic abscesses. The interobserver agreement was also analyzed for each variable.ResultsThe multivariate analysis revealed that the conspicuity discrepancy (odds ratio [OR] 34.78, 95% confidence interval [CI] 2.09–579.47, p = 0.013) and non-peripheral high signal intensity (SI) rim on DWI (OR 67.46, 95% CI 2.64, 1723.20, p = 0.011) were significant independent factors for predicting atypical hepatic abscesses. They were also shown to be high predictor points on the nomogram. When any of the set criteria were satisfied, 97.7% of atypical hepatic abscesses were correctly identified, with a specificity of 65.7%. When both criteria were combined, the specificity was up to 100%, with a sensitivity of 44.9%.ConclusionConspicuity discrepancy and a non-peripheral high SI rim on DWI are reliable and meaningful features that can distinguish atypical hepatic abscesses from hepatic metastases.

Sex-Related Differences in Clinical Features, Neuroimaging, and Long-Term Prognosis After Transient Ischemic Attack.

Background and Purpose:Differences in sex in the incidence, presentation, and outcome of events after ischemic stroke have been studied in depth. In contrast, only limited data are available after transient ischemic attack (TIA). We aim to assess sex-related differences in the presentation, cause, neuroimaging features, and predictors of long-term prognosis in patients with TIA.Methods:We carried out a prospective cohort study of consecutive patients with TIA from January 2006 to June 2010. Nondefinitive TIA events were defined by the presence of isolated atypical symptoms. The risk of stroke recurrence (SR) and composite of major vascular events were stratified by sex after a median follow-up time of 6.5 (interquartile range, 5.0–9.6) years.Results:Among the 723 patients studied, 302 (41.8%) were female and 79 (10.9%) suffered a nondefinitive TIA event. Vascular territory diffusion-weighted imaging patterns (odds ratio, 1.61 [95% CI, 0.94–2.77]), and nondefinitive TIA events (odds ratio, 2.66 [95% CI, 1.55–4.59]) were associated with women, whereas active smoking (odds ratio, 0.30 [95% CI, 0.15–0.58]) and large artery atherosclerosis causes (odds ratio, 0.50 [95% CI, 0.29–0.83]) were related to men. The risk of SR was similar in both sexes (12.6% [95% CI, 8.9–16.3] for women versus 14.3% [95% CI, 11.0–17.6] for men). In contrast, the risk of major vascular events was significantly lower in women than in men (17.5% [95% CI, 13.2–21.8] versus 23.8% [95% CI, 19.7–27.9]). In both sexes, after adjusting for age, large artery atherosclerosis was associated with SR (hazard ratio, 3.22 [95% CI, 1.42–7.24] and hazard ratio, 2.00 [95% CI, 1.14–3.51]). In a Kaplan-Meier analysis, females with positive diffusion-weighted imaging (P=0.014) and definitive TIA (log-rank test P=0.022) had a significantly higher risk of SR.Conclusions:Despite similar risks of SR, there were sex-related differences in baseline characteristics, presenting symptoms, patterns of acute ischemic lesions, cause, and outcomes. These findings encourage further research into optimal preventive strategies that take into account these differences.

Diffusion weighted imaging improves diagnostic ability of MRI for determining complete response to neoadjuvant therapy in locally advanced rectal cancer

PurposeTo assess the diagnostic performance, interobserver agreement and confidence level for determining response to neoadjuvant chemoradiotherapy (NACRT) using morphology based MR-tumour regression grade (MR TRG), diffusion weighted imaging (DWI) patterns and their combination in patients with locally advanced rectal cancer. MethodsThis was a retrospective study including patients with locally advanced rectal cancer treated with NACRT and subsequent surgery. Two independent radiologists blinded to the histopathology reviewed staging and restaging MRI. Diagnostic performance of morphology based MR-TRG, DWI patterns and their combination for determining complete (CR) and incomplete (IR) response was assessed with pathological response as the reference. Likert’s scale was used to assess the radiologist’s level of confidence. Interobserver agreement was determined using Kappa statistics. ResultsThe study included 251 patients (mean age of 47.9+/-14 (range 19–86) years, M:F = 164:87). Rate of pathological CR was 14.7 % (n = 37). Pattern based interpretation of DWI and combined approach (DWI + T2-HR) had superior diagnostic performance than morphology based assessment alone with area under curve (AUC) for T2HR, DWI and their combination being 0.531, 0.887, 0.874 respectively for observer 1 and 0.558, 0.653, 0.678 respectively for observer 2, p < 0.001. Interobserver agreement was substantial (k = 0.688) for combined approach, moderate (k = 0.402) for DWI patterns and fair (k = 0.265) for T2 HR MRI with both observers exhibiting highest level of confidence for determining response with the combined approach. ConclusionComplete response to neoadjuvant chemoradiotherapy can be determined with excellent accuracy, substantial interobserver agreement and high level of confidence by combined interpretation of DWI and T2 high resolution MRI.

D-dimer and diffusion-weighted imaging pattern as two diagnostic indicators for cancer-related stroke: A case-control study based on the STROBE guidelines.

The aim of this study was to evaluate the risk factors and elucidate the clinical characteristics of cancer-associated ischemic stroke to differentiate it from conventional ischemic stroke in China and East Asia. Between June 2012 and June 2016, a retrospective analysis was performed on 609 stroke patients with cancer. They were divided into 3 groups: cancer-stroke group (CSG, 203 cases), stroke group (SG, 203 cases), and cancer group (CG, 203 cases). The d-dimer levels and diffusion-weighted imaging lesion (DWI) pattern were compared to an age- and sex-matched control group. The most common cancer types were colorectal cancer (20.2%) and lung cancer (18.72%). The average d-dimer level in stroke patients and cancer patients were 0.34 and 1.50 mg/L, respectively. The descending levels of d-dimer from cancer types were lung cancer (2.06 mg/L), pancreas (1.74 mg/L), gastric (1.61 mg/L), among others. Univariate analysis of the CSG and the others shows there were significant differences in the prevalence of the levels of d-dimer and DWI pattern, hypertension, diabetes mellitus, and thrombus. CSG has a unique pathological characteristic including high plasma d-dimer levels and multiple vascular lesions. The results show that d-dimer and DWI can be used as diagnostic index in clinical practice.

Diffusion-Weighted Imaging Patterns According to the Right-to-Left Shunt Amount in Cryptogenic Stroke

Background: Although patent foramen ovale (PFO) is considered to be the main cause of cryptogenic stroke, it is difficult to define “true” PFO-related stroke. Objective: In this study, we evaluated comprehensive diffusion-weighted imaging (DWI) findings in patients with cryptogenic stroke according to the right-to-left shunt (RLS) amounts on transcranial Doppler (TCD) sonography. Methods: We assessed consecutive patients with cryptogenic stroke between October 2010 and 2018. The RLS amount on TCD was assessed according to the International Consensus Criteria (ICC). Massive RLS was defined as the highest category of ICC (Curtain pattern). We assessed DWI findings, including the location of lesions, involved vascular territory, and DWI lesion patterns. Results: A total of 100 consecutive patients with cryptogenic stroke were assessed, and PFO was found in 59 patients. In multivariable analyses, massive RLS was noted to be positively associated with the presence of cortical lesion (adjusted OR [aOR] 15.75, 95% CI 1.94–127.71, p = 0.010), multiple territory involvement (aOR 5.24, 95% CI 1.57–17.53, p = 0.007), and number of DWI lesions (beta 0.713, 95% CI 0.245 to 1.181, p = 0.003) after adjusting for confounders. Conversely, massive RLS showed inverse correlations with posterior circulation involvement (aOR 0.22, 95% CI 0.06–0.87, p= 0.031) and number of large DWI lesions (beta –0.328, 95% CI –0.629 to –0.026, p = 0.034). Conclusions: We demonstrated that massive RLS on TCD was associated with multiple, small-scattered cortical lesion in patients with cryptogenic stroke. These DWI pattern is highly suggestive of PFO-related stroke.

Prognostic markers for immunodeficiency-associated primary central nervous system lymphoma

Immunodeficiency is a major risk factor for primary central nervous system lymphoma (PCNSL), but data on the disease in immunocompromised hosts are scarce. We aimed to define clinical and imaging features and determine prognostic factors for immunodeficiency-associated PCNSL. All PCNSL cases seen at Yale-New Haven Hospital between 2002 and 2017 were retrospectively screened for immunodeficiency. For patients with immunosuppression, biopsies were evaluated and clinical data were collected. Predictors of survival were identified using Kaplan-Meier survival analysis and log-rank test. p values < 0.05 were considered significant. 23 patients with immunodeficiencies were identified: eleven on immunosuppressants after solid organ transplantation, seven with human immunodeficiency virus infection, and five on immunosuppressive treatment due to various autoimmune disorders. PCNSL cases were largely Epstein-Barr-Virus positive (78%), histologically classified as diffuse large B cell lymphomas (87%), and showed peripheral contrast enhancement (81%) and corresponding heterogeneous diffusion-weighted imaging patterns (DWI) on magnetic resonance imaging (MRI) (71%). Median overall survival was 31months. Age > 60years at diagnosis (p < 0.01), peripheral enhancement of the mass on MRI (p = 0.04), heterogeneous DWI patterns (p = 0.04), and clonal immunoglobulin heavy chain gene rearrangement (IgHR) (p = 0.03) were found to be negative prognostic markers. Immunodeficiency-associated PCNSL presents with similar clinical, pathological and imaging features. Age > 60years, clonal IgHR, heterogeneous DWI pattern and peripheral enhancement on MRI may serve as predictors of less favorable outcome.

Prognostic value of phase information of 2D T2*-weighted gradient echo brain imaging in cardiac arrest survivors: A preliminary study

BackgroundPredicting neurological outcomes after cardiac arrest is important to guide therapeutic decisions. We assessed the prognostic value of phase information of 2D T2*-weighted gradient echo imaging (T2*WI) of the brain in CA survivors. MethodsThis study included cardiac arrest survivors who had undergone MRI for prognostication. After application of homodyne filtering to T2*WI phase images, the contrast of three venous structures was assessed as normal (score 0) or abnormal (score 1): the superior sagittal sinus, the cortical veins, and the thalamostriate veins. The scores were summarized into a gradient-recalled echo (GRE) summary score. The prognostic performances of T2*WI, diffusion-weighted imaging (DWI), electroencephalography and serum biomarkers were evaluated using receiver operating characteristic (ROC) curves. ResultsOf the 39 enrolled patients, 12 (31%) had good outcomes and 27 (69%) had poor outcomes. ROC curve analysis showed that T2*WI had good prognostic performance; the area under the curve (AUC) of the GRE summary score (0.980, 95% confidence interval CI 0.950–1.000) was comparable to those of conventional outcome predictors, including DWI patterns (0.949, 95% CI 0.889–1.000). The AUC increased when the summary GRE score was added to DWI patterns (0.991, 95% CI 0.973–1.000), although the difference was not statistically significant (P=0.117). Most subjects with isoelectric electroencephalography (5/6) showed abnormally high phase contrast in the cerebral veins. ConclusionsFiltered phase images of T2*WI showed good prognostic value and can reveal various features of the cerebral metabolic consequences of cardiac arrest, such as decreased neuronal activity and brain death-like patterns.

Brain Diffusion Imaging Findings May Predict Clinical Outcome after Cardiac Arrest.

We aim to correlate the patterns of brain diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) map in post cardiac arrest (PCA) patients with clinical outcomes. Thirty-eight adult patients with PCA (mean age, 52.8 years; range 18-87 years) whose DWI obtained within 5 days of PCA were retrospectively reviewed. The visual DWI/ADC map categories include: Group 1: Normal; Group 2a: Mild [restricted diffusion (RD) < 1/3 cortical involvement (CI)]); Group 2b: Moderate (RD 1/3 > and < 2/3 CI); Group 2c: Severe (RD > 2/3 CI); and Group 3: Embolic (scattered, discrete foci of RD). Clinical outcomes were categorized according to cerebral performance categories (CPC) and modified Rankin scale (mRS). The most common DWI/ADC map pattern was Group 1 (28.9%, n = 11). The incidence of other DWI patterns such as Group 2a, 2b, 2c, and 3 were 21% (n = 8), 10.5% (n = 4), 21% (n = 8), and 18.4% (n = 7), respectively. Twenty-seven patients (71%) were CPC-5/mRS-6 and died or were category CPC-4/mRS-5, and 4 patients were CPC-1/mRS 0-1 (10.5%). Interobserver agreement for visual classification of DWI/ADC map patterns was excellent (kappa = .8795). There was moderate positive correlation between clinical outcomes and visual DWI classification (r = .461, P = .00358). The positive predictive value of this qualitative classification on DWI/ADC in predicting a poor clinical outcome (CPC-4/mRS-5 and CPC-5/mRS-6) was 81.4 % in the presence of restricted diffusion. Simple visual categorization system using DWI/ADC map may be helpful and practical in estimating the clinical outcome of PCA patients.

Combining Diffusion-Weighted Imaging Patterns with ABCD2 Score Predicts Stroke Risk after Transient Ischemic Attack.

Recent studies indicated that multiple acute infarctions on Diffusion- Weighted Imaging (DWI) were associated with a higher risk of stroke. The study aims to estimate the association of different infarction patterns and ABCD2 score with the prognosis of Transient Ischemic Attack (TIA). We prospectively analyzed the data from TIA database of the First Affiliated Hospital of Zhengzhou University. The predictive outcome was a 90-day ischemic stroke. Cox proportional hazards model was used to evaluate the predictive value of risk factors associated with stroke. The receiver-operating characteristics curves were plotted, and the predictive value was assessed by computing the Area Under the Curve (AUC). A total of 1376 eligible patients were enrolled. DWI patterns were significant predictors for stroke (single acute infarction: hazard ratio [HR] =2.942, p <0.001; multiple acute infarctions: HR =5.552, p <0.001, in comparison with no acute infarction). Patients with both multiple infarctions and ABCD2 ≥4 were associated with approximately 15.5-fold risk of stroke at 90 days (28.8% vs. 2.1%, HR =15.455, 95% confidence interval [CI], 7.946-30.057, p <0.001), compared with those with no infarction or ABCD2 <4. The ABCD2+ DWI patterns showed a better discrimination with an AUC of 0.765 (95% CI, 0.741-0.787) than the ABCD2 score (AUC =0.651; 95% CI, 0.625-0.676; Z =4.777; p <0.0001) and ABCD3-I score (AUC =0.724; 95% CI, 0.700- 0.748; Z =2.697; p =0.007). Combining infarction patterns with ABCD2 score could enhance the predictive value for early stroke risk in TIA.

Mass-forming intrahepatic cholangiocarcinoma: Can diffusion-weighted imaging predict microvascular invasion?

Microvascular invasion (MVI) is a risk factor influencing the survival rate of patients with mass-forming intrahepatic cholangiocarcinoma (IMCC). To investigate whether diffusion-weighted imaging (DWI) could be useful in predicting MVI of IMCC. Retrospective. Eighty patients with surgically resected single IMCC (21 MVI-positive lesions and 59 MVI-negative lesions). Preoperative hepatic MRI (1.5T), including T1 - and T2 -weighted images (T1 WI, T2 WI), DWI, and dynamic enhancement imaging. Morphologic characteristics including contour of the lesion, biliary dilation and hepatic capsule retraction, signal features on T1 WI, T2 WI, and DWI, and dynamic enhancement patterns were qualitatively evaluated. The quantitative analysis was performed for the size and apparent diffusion coefficient (ADC) values. Chi-square test, Fisher's exact test, and the independent t-test were used for univariate analysis to determine the relationships between these radiological parameters and the presence of MVI. Logistic regression analysis was used to identify the independent predictors of MVI among these radiological parameters. Receiver operating characteristic curve analysis was performed to evaluate their diagnostic performance. Larger tumor size (P = 0.006) and higher ADC values (P < 0.001) were positively correlated with MVI. Multivariate logistic regression analysis demonstrated that the ADC value (odds ratio, 3.099; P = 0.001) was an independent predictor for MVI of IMCC. The ADC value for MVI of IMCC showed an area under the receiver operating characteristic curve of 0.782 (optimal cutoff value was 1.59 × 10-3 mm2 /s). Larger tumor size was associated with MVI and higher ADC values can be a useful predictor of MVI during the preoperative evaluation of IMCC. 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:315-324.

A Pattern-Based Approach Combining Tumor Morphology on MRI With Distinct Signal Patterns on Diffusion-Weighted Imaging to Assess Response of Rectal Tumors After Chemoradiotherapy.

Diffusion-weighted imaging is increasingly used in rectal cancer MRI to assess response after chemoradiotherapy. Certain pitfalls (eg, artefacts) may hamper diffusion-MRI assessment, leading to suboptimal diagnostic performance. Combining diffusion-weighted MRI with the underlying morphology on standard (T2-weighted) MRI may help overcome these pitfalls. The purpose of this study was to evaluate the diagnostic performance of a pattern-based approach combining tumor morphology on T2-weighted MRI with distinct diffusion-weighted imaging signal patterns to assess response after chemoradiotherapy in rectal cancer. Response to chemoradiotherapy was scored according to 4 patterns: 1) cases with either a clear residual mass with corresponding high-diffusion signal (A+) or completely normalized wall without diffusion signal (A-); 2) cases with circular and/or irregular fibrosis with (B+) or without (B-) small foci of diffusion signal scattered throughout the fibrosis; 3) cases with semicircular fibrosis with (C+) or without (C-) high diffusion signal at the inner margin of the fibrosis; and 4) polypoid tumors showing regression of the polyp and fibrosis at the site of the stalk with (D+) or without (D-) focal high-diffusion signal in the stalk. A total of 75 cases were rescored by an independent second reader to study interobserver variations. Standard of reference was histopathology or long-term outcome. The study was conducted at a single tertiary referral center. A total of 222 patients with locally advanced rectal cancer undergoing chemoradiotherapy were included. Diagnostic performance to discriminate between a complete response and residual tumor was measured. The pattern-based approach resulted in a sensitivity of 94%, specificity of 77%, positive predictive value of 88%, negative predictive value of 87%, and overall accuracy of 88% to differentiate between tumor versus complete response. Accuracies per pattern were 100% (A), 74% (B), 86% (C), and 92% (D). Interobserver agreement was good (κ = 0.75). The study included no comparison with routine (nonpattern) diffusion-MRI assessment. A pattern-based approach combining tumor morphology with distinct diffusion-weighted imaging patterns results in good diagnostic performance to assess response. See Video Abstract at http://links.lww.com/DCR/A433.

D-dimer levels and cerebral infarction in critically ill cancer patients

BackgroundD-dimer levels have been used in the diagnosis of a variety of thrombosis-related diseases. In this study, we evaluated whether measuring D-dimer levels can help to diagnose cerebral infarction (CI) in critically ill cancer patients.MethodsWe retrospectively evaluated all cancer patients who underwent brain magnetic resonance imaging (MRI) between March 2010 and February 2014 at the medical oncology intensive care unit (ICU) of Samsung Medical Center. Brain MRI scanning was performed when CI was suspected due to acute neurological deficits. We compared D-dimer levels between patients ultimately diagnosed as having or not having CI and analyzed diffusion-weighted imaging (DWI) lesion patterns.ResultsA total of 88 patients underwent brain MRI scanning due to clinical suspicion of CI; altered mental status and unilateral hemiparesis were the most common neurological deficits. CI was ultimately diagnosed in 43 (49%) patients. According to the DWI patterns, multiple arterial infarctions (40%) were more common than single arterial infarctions (9%). Cryptogenic stroke etiologies were more common (63%) than determined etiologies. There was no significant difference in D-dimer levels between patients with and without CI (P = 0.319). Although D-dimer levels were not helpful in diagnosing CI, D-dimer levels were associated with cryptogenic etiologies in critically ill cancer patients; D-dimer levels were higher in the cryptogenic etiology group than in the determined etiology group or the non-infarction group (P = 0.001). In multivariate analysis, elevated D-dimer levels (> 8.89 μg/mL) were only associated with cryptogenic stroke (adjusted OR 5.46; 95% confidence interval, 1.876–15.857).ConclusionsAbnormal D-dimer levels may support the diagnosis of cryptogenic stroke in critically ill cancer patients.

Intrahepatic mass-forming cholangiocarcinoma and solitary hypovascular liver metastases: is the differential diagnosis using diffusion-weighted MRI possible?

Background Intrahepatic mass-forming cholangiocellular carcinoma (IMC) is the second most common primary liver tumor. The differentiation between IMC and solitary hypovascular liver metastases (SHLM) represents a diagnostic challenge due to many overlapping magnetic resonance imaging (MRI) features. Purpose To determine the value of diffusion-weighted imaging (DWI) in addition to conventional MRI for the distinction between intrahepatic mass-forming cholangiocarcinoma and solitary hypovascular liver metastases. Material and Methods Fifty-three patients with pathologically proven IMC (n = 31) and SHLM (n = 22) who had undergone MRI and DWI before surgery or percutaneous biopsy were enrolled in this study. The following MRI features were analyzed: the size and shape of the lesion, presence of capsular retraction and segmental biliary dilatation, T2-weighted (T2W) signal intensity, the presence of target sign on DWI and enhancement pattern. Apparent diffusion coefficient (ADC) values were calculated for each lesion ( b = 800 s/mm2). Univariate and multivariate logistic regression analyses were used to identify significant differentiating features between IMCs and SHLMs. Results Univariate analysis revealed that following parameters favor diagnosis of IMCs over SHLMs: lobulating shape, heterogeneous T2W signal intensity, capsular retraction, segmental biliary dilatation, target sign on DWI and rim-like enhancement on arterial phase followed by progressive enhancement in delayed phases. ADC values measured in the periphery of the lesion were significantly lower in IMCs in comparison to SHLMs. Multivariate analysis revealed that target sign on DWI was the most significant predictor of IMCs. Conclusion Qualitative DWI analysis with target sign significantly improves diagnostic accuracy for differentiation among IMC and SHLM lesions.

Metabolomics Predicts Neuroimaging Characteristics of Transient Ischemic Attack Patients

BackgroundNeuroimaging is essential for the diagnosis and prognosis of transient ischemic attack (TIA). The discovery of a plasmatic biomarker related to neuroimaging findings is of enormous interest because, despite its relevance, magnetic resonance diffusion weighted imaging (DWI) is not always available in all hospitals that attend to TIA patients. MethodsMetabolomic analyses were performed by liquid chromatography coupled to mass spectrometry in order to establish the metabolomic patterns of positive DWI, DWI patterns and acute ischemic lesion volumes. We used these methods with an initial TIA cohort of 129 patients and validated them with a 2nd independent cohort of 152 patients. FindingsPositive DWI was observed in 115 (40.9%) subjects and scattered pearls in one arterial territory was the most frequent lesion pattern (35.7%). The median acute ischemic lesion volume was 0.33 (0.15–1.90)cm3. We detected a specific metabolomic profile common to both cohorts for positive DWI (11 molecules including creatinine, threoninyl-threonine, N-acetyl-glucosamine, lyso phosphatidic acid and cholesterol-related molecules) and ischemic lesion volume (10 molecules including lysophosphatidylcholine, hypoxanthine/threonate, and leucines). Moreover lysophospholipids and creatinine clearly differed the subcortical DWI pattern from other patterns. InterpretationThere are specific metabolomic profiles associated with representative neuroimaging features in TIA patients. Our findings could allow the development of serum biomarkers related to acute ischemic lesions and specific acute ischemic patterns.

Distinctive pattern of white matter injury in neonates with rotavirus infection.

To report a consecutive series of neonates with seizures or apnea and displaying white matter injuries with distinctive magnetic resonance diffusion-weighted imaging (DWI) pattern, and to discuss the high positive rate of rotavirus infection seen in these patients. In a retrospective review of neonates who were admitted to a tertiary referral center with seizures or apnea, we found a distinctive pattern of white matter injury (symmetrical restricted diffusion in the periventricular white matter and white matter tracts including the corpus callosum) in 18 patients. We describe the clinical and laboratory features of these 18 neonates. Additional PCR analyses for rotaviruses and parechoviruses were performed on banked frozen samples of CSF of 4 patients and blood of 15 patients. All 18 patients were born at term and healthy until symptoms occurred 4-7 days after birth. No history of asphyxia was observed. Only 1 patient presented with fever, and no patient showed a rash. All patients except 1 (94.4%) were rotavirus-positive in stool samples. However, neither rotaviruses nor enteroviruses/parechoviruses were detected in the CSF and blood. Tissue loss was observed in 5 of 8 subjects on repeat MRI scans. Neonates with this distinctive DWI pattern had a high positive rate of rotavirus infection, without evidence of other pathogens, and were characterized as term newborns with neurologic symptoms arising approximately the fifth day after birth. Although the specificity of this pattern is unclear, rotavirus testing should be considered for neonates presenting with this DWI pattern.

Status Epilepticus Amauroticus Revisited

To describe the clinical, electrographic, and radiographic features of status epilepticus amauroticus, or homonymous hemianopsia associated with partial status epilepticus, in 3 patients w:h subsequent resolution of radiographic abnormalities and visual deficits. Case series. Rancho Los Amigos National Rehabilitation Center in Downey, California, and the Los Angeles County + University of Southern California Medical Center. One patient with a single remote seizure and 2 patients with symptomatic partial epilepsy all presented with homonymous hemianopsia. Continuous electroencephalographic monitoring, magnetic resonance imaging, and antiepileptic medical therapy for status epilepticus. Neurologic examination, electroencephalography, and magnetic resonance imaging. The association of homonymous hemianopsia and restricted diffusion on magnetic resonance imaging led to an initial diagnosis of ischemic infarction in 2 cases despite atypical diffusion-weighted imaging patterns. However, continuous electroencephalogram demonstrated focal epileptiform discharges in 2 cases and repetitive focal seizures in another, suggesting a diagnosis of status epilepticus amauroticus. Homonymous hemianopsia resolved in all 3 patients after escalation of the dosage of anticonvulsant therapy. Follow-up magnetic resonance imaging and electroencephalogram demonstrated complete or near-complete resolution of associated abnormalities. Status epilepticus amauroticus is an uncommon but important cause of homonymous hemianopsia, and it should be considered in any patient with a history of seizures, fluctuating visual symptoms, or atypical patterns of restricted diffusion involving the occipital cortex. Continuous electroencephalographic monitoring is an important diagnostic tool for the diagnosis of status epilepticus amauroticus, which may have a favorable prognosis when treated with aggressive anticonvulsant therapy.

Perfusion-Weighted MRI as a Predictor of Clinical Outcomes following Medullary Infarctions

Background: Perfusion-weighted imaging (PWI) is rarely used to evaluate cases of posterior circulation infarctions. We evaluated clinical outcomes, diffusion-weighted imaging (DWI) patterns and angiographic findings in patients experiencing medullary infarctions according to PWI results. Methods: Data from consecutive patients with acute ischemic lesions primarily involving the medulla were analyzed. All patients underwent MRI including DWI, PWI and MR angiography. The patients were grouped according to the presence or absence of a perfusion delay in the medulla and/or inferior cerebellum. Results: Among 35 patients, all but 1 had a PWI of interpretable quality. Of these 34 patients, 18 had a normal perfusion status, while 16 had perfusion defects in the medulla and/or inferior cerebellum. The abnormal PWI group had poor clinical outcomes at 7 days and 1 month after the onset of symptoms. There was no difference in DWI patterns between these 2 groups. The angiographic findings demonstrated that a stenosis of ≧50% or an occlusion of the ipsilesional vertebral artery was frequently observed in the abnormal PWI group (p = 0.001). Multivariate analysis revealed that abnormal PWI and DWI patterns were independently associated with poor early and late outcomes following medullary infarctions. Conclusions: PWI may be a feasible modality for assessing the perfusion status of the posterior circulation and predicting clinical outcomes following medullary infarctions.