Diagnostic accuracy of diffusion-weighted imaging in variant Creutzfeldt-Jakob disease.

PURPOSE: This study sought to investigate the diagnostic sensitivity of diffusion-weighted imaging (DWI) in variant Creutzfeldt-Jakob disease (vCJD), a prion disease with significant public health implications on account of its transmissibility. The importance of this research stemmed from the first neuropathologically confirmed vCJD case in a PRNP heterozygous individual in 2016, which displayed DWI features typical of sporadic CJD (sCJD). The case was classified as 'probable' sCJD in life, predominantly based on these imaging findings. While DWI has proven valuable in diagnosing sCJD, its utility in vCJD diagnosis remains unclear. METHODS: DWI and Fluid-attenuated inversion recovery (FLAIR) images from probable and definite vCJD cases referred to the National CJD Research and Surveillance Unit (NCJDRSU) were independently analysed by an expert neuroradiologist. Scans were reviewed within a mixed cohort of CJD cases including definite sCJD and non-CJD controls. RESULTS: FLAIR sequences demonstrated greater sensitivity in identifying the pulvinar sign in vCJD compared to DWI (73% vs 41%, p-value <0.001). Basal ganglia hyperintensities were more prevalent in DWI (84%) than FLAIR (64%), and cortical hyperintensities were exclusive to DWI (24%). The pulvinar sign showed a specificity of 98% for vCJD and was rare in sCJD. CONCLUSION: DWI showed reduced sensitivity compared to FLAIR imaging in detecting the pulvinar sign in vCJD. Conversely, DWI can more distinctively identify basal ganglia and cortical hyperintensities, thus leading to imaging patterns more characteristic of sCJD. Therefore, DWI should be cautiously interpreted in vCJD diagnosis, with axial FLAIR potentially providing a more precise evaluation of the pulvinar sign.

Clinical value of conventional magnetic resonance imaging combined with diffusion-weighted imaging in predicting pelvic lymph node metastasis of cervical cancer.

Background: In cervical cancer (CC), the involvement of pelvis lymph nodes is a crucial factor for patients' outcome. We aimed to investigate the value of conventional magnetic resonance imaging (MRI) combined with diffusion-weighted imaging (DWI) and the apparent diffusion coefficient (ADC) in predicting CC pelvic lymph node metastasis (PLNM). Methods: This retrospective study included CC patients who received surgical treatments. Surgical pathology results served as the gold standard for investigating the diagnostic performance of conventional MRI combined with DWI. We analyzed the association between tumor ADC and PLNM, as well as other pathological factors. The areas under the receiver operating characteristic curves (AUCs) for ADC in assessing PLNM and pathological factors were evaluated, and optimal cut-off points were obtained. Results: A total of 261 CC patients were analyzed. PLNM patients had significantly lower tumor ADC (0.829 ± 0.144×10-3mm2/s vs. 1.064 ± 0.345×10-3mm2/s, p<0.0001), than non-PLNM CC. The agreement between conventional MRI combined with DWI and pathological results on PLNM diagnosis was substantial (Kappa=0.7031, p<0.0001), with 76% sensitivity, 94.31% specificity, and 90.8% accuracy. The AUC of tumor ADC was 0.703, and the optimal cut-off was 0.95×10-3 mm2/s. In multivariate analysis model 1, tumor ADC<0.95×10-3mm2/s was significantly associated with PLNM (OR, 2.83; 95%CI, 1.08-7.43; p= 0.0346) after adjusting for age and pathological risk factors. In multivariate analysis model 2, tumor ADC<0.95×10-3mm2/s (OR, 4.00; 95%CI, 1.61-9.89; p=0.0027), age<35 years old (OR, 2.93; 95%CI, 1.04-8.30; p=0.0428), increased tumor diameter on MRI (OR, 2.17; 95%CI, 1.18-3.99; p=0.0128), vaginal vault involvement on MRI (OR, 2; 95%CI, 1.002-3.99; p=0.0494) were independent predictors for PLNM. Tumor ADC<0.95×10-3mm2/s was significantly associated with higher risk of tumor diameter ≥4cm (OR, 2.60; 95%CI, 1.43-4.73; p=0.0017), muscular layer infiltration >1/2 (OR, 5.46; 95%CI, 3.19-9.34; p<0.0001), vaginal vault involvement (OR, 2.25; 95%CI, 1.28-3.96; p=0.0051), and lymphovascular space involvement (OR, 3.81; 95%CI, 2.19-6.63; p<0.0001). Conclusion: Conventional MRI combined with DWI had a good diagnostic performance in detecting PLNM. The tumor ADC value in PLNM patients was significantly lower than that in non-PLNM patients. Tumor ADC <0.95×10-3mm2/s, age <35 years old, increased tumor diameter on MRI, vaginal vault involvement on MRI were independent predictors for PLNM.

Tissue Window versus Time Window? A Review of Patients Receiving Extended Hours Thrombolysis Guided By DWI-FLAIR Mismatch : Case Series

@#Introduction: Intravenous thrombolysis (IVT) is the gold standard for the treatment of patients with acute ischemic stroke (AIS) presenting within four and a half hours of onset. However, development of new thrombolytic agents and advanced imaging has led to extended time for thrombolysis based on advanced imaging. Here we describe four patients who presented in the extended hours; that benefitted from thrombolysis. Case series: We advocate magnetic resonance imaging (MRI) for AIS, that includes diffusion weighted imaging (DWI), apparent diffusion coefficient (ADC), fluid attenuated inversion recovery (FLAIR), susceptibility weighted imaging (SWI), and magnetic resonance angiography (MRA). We included four patients who were more than 18 years old, with National Institute of Health Stroke Scale (NIHSS) of six or more, presenting between four and a half to nine hours after stroke onset with no contraindications for intravenous thrombolysis. The imaging criteria used to determine eligibility for IVT is evidence of DWI-FLAIR mismatch on MRI. If FLAIR detects no signal change in the area of stroke on DWI, it is then termed DWIFLAIR mismatch, or FLAIR-negative – indicating high probability that the brain tissue is still viable, and that patients are good candidates for IVT. Conclusion: For patients with AIS who present within nine hours, DWI-FLAIR mismatch serves as an excellent surrogate marker of salvageable brain tissue, allowing a greater proportion of patients benefiting from this life-saving therapy. Our experience also shows that with careful patient selection, treatment with IVT can safely be given without an increased risk of bleeding or mortality.

[A case of acute hyperammonemic encephalopathy with extensive cortical high-intensity lesions in diffusion weighted imaging].

A 49-year-old woman with hepatic failure owing to alcoholic liver cirrhosis went into a deep coma. Her serum ammonia concentration was elevated at 436 µg/dl, and she had a generalized convulsion. Electroencephalogram and cerebrospinal fluid examination did not suggest encephalitis and epilepsy. Hyperammonemia may be occur because of generalized convulsions; however, it can spontaneously resolve if the convulsions are stopped. If hyperammonemia is the primary cause of generalized convulsion, the serum ammonia concentration will remain high until the cause is eliminated. However, despite stopping the convulsions, her ammonia concentration remained high. Diffusion-weighted brain MRI revealed symmetric high-intensity lesions in the frontal, temporal, and parietal cortices, especially the cingulate and insular cortices of the bilateral hemispheres. These findings were in line with those of previous reports that revealed symmetric cortical lesions, including cingulate and insula cortices that are distinctive in acute hyperammonemic encephalopathy. Therefore, we diagnosed that the coma, generalized convulsions, and abnormal brain MRI findings were caused by acute hyperammonemic encephalopathy.

Application value of MRI diffuse weighted imaging combined with PET/CT in the diagnosis of stomach cancer at different stages.

Value of MRI diffusion-weighted imaging (MRI DWI) combined with PET/CT in the diagnosis and staging of stomach cancer (SC) was investigated. A retrospective analysis was performed on 160 patients with SC diagnosed by pathological biopsy in The Affiliated Yantai Yuhuangding Hospital of Qingdao University from March 2015 to April 2018. The values of MRI DWI, PET/CT and combined diagnosis in the diagnosis and staging of SC were compared according to the criteria of diagnosis of postoperative pathological or clinical comprehensive evaluation. The sensitivity, specificity and diagnostic coincidence rate of MRI DWI in the diagnosis of SC at stage I-II were 61.05, 64.62 and 62.50%, respectively, which were significantly lower than those of PET/CT (P<0.05). Sensitivity, specificity and diagnostic coincidence rate of MRI DWI in the diagnosis of SC at stage III-IV were lower than those of PET/CT (P<0.05). Sensitivity and diagnostic coincidence rate of MRI DWI combined with PET/CT in the diagnosis of SC at stage I-II were significantly higher than those of MRI DWI or PET/CT alone (P<0.05). Specificity and diagnostic coincidence rate of MRI DWI combined with PET/CT in the diagnosis of SC at stage III-IV were significantly higher than those of MRI DWI or PET/CT alone (P<0.05). PET/CT is superior to MRI DWI in SC staging, whereas the diagnostic efficiency of combined scan is much higher than that of PET/CT or MRI DWI alone. In order to obtain more accurate preoperative staging and to avoid diagnostic exploratory laparotomy, the combination of MRI DWI and PET/CT techniques should be used in the comprehensive analysis of the disease to improve the accuracy of clinical diagnosis.

Noninvasive assessment and quantification of tumour vascularisation using MRI and CT in a tumour model with modifiable angiogenesis - An animal experimental prospective cohort study.

BACKGROUND: To investigate vascular-related pathophysiological characteristics of two human lung cancers with modifiable vascularisation using MRI and CT. METHODS: Tumour xenografts with modifiable vascularisation were established in 71 rats (approval by the Animal Care Committee was obtained) by subcutaneous transplantation of two human non-small-cell lung cancer (NSCLC) cells (A549, H1299) either alone or co-transplanted with vascular growth promoters. The vascularity of the tumours was assessed noninvasively by MRI diffusion-weighted-imaging (DWI), T2-weighted, and time-of-flight (TOF) sequences) as well as contrast-enhanced CT (CE-CT), using clinical scanners. As a reference standard, histological examinations (CD-31, fluorescent beads) were done after explantation. RESULTS: Microvessel density (MVD) was higher in co-transplanted tumours (171 ± 19 number/mm2) than in non-co-transplanted tumours (111 ± 11 number/mm2; p = 0.002). Co-transplanted tumours showed higher growth rates and larger tumour vessels at TOF-MRI as well as larger necrotic areas at CE-CT. In co-transplanted tumours, DWI revealed higher cellularity (lower minimal ADCdiff 166 ± 15 versus 346 ± 27 mm2/s × 10-6; p < 0.001), highly necrotic areas (higher maximal ADCdiff 1695 ± 65 versus 1320 ± 59 mm2/s × 10-6; p < 0.001), and better-perfused tumour stroma (higher ADCperf 723 ± 36 versus 636 ± 51 mm2/s × 10-6; p = 0.005). Significant correlations were found using qualitative and quantitative parameters: maximal ADCperf and MVD (r = 0.326); maximal ADCdiff and relative necrotic volume on CE-CT (r = 0.551); minimal ADCdiff and MVD (r = -0.395). CONCLUSIONS: Pathophysiological differences related to vascular supply in two human lung cancer cell lines with modifiable vascularity are quantifiable with clinical imaging techniques. Imaging parameters of vascularisation correlated with the results of histology. DWI was able to characterise both the extent of necrosis and the level of perfusion.

Earlier and more specific detection of persistent neck disease with diffusion-weighted MRI versus subsequent PET/CT after definitive chemoradiation for oropharyngeal squamous cell carcinoma.

BACKGROUND: The purpose of this study was to test if diffusion-weighted imaging (DWI) identified persistent neck disease after chemoradiotherapy (CRT) for oropharyngeal cancer earlier and as accurately as subsequent positron emission tomography (PET)/CT. METHODS: We performed a review of patients with oropharyngeal cancer treated with definitive CRT who underwent DWI and PET/CT at a median of 8 and 14 weeks posttreatment. Imaging characteristics were correlated with pathologically proven neck failure. RESULTS: Forty-one patients and 58 hemi-necks were analyzed. With a median follow-up of 120 weeks, 4 neck failures were identified. The apparent diffusion coefficient (ADC) of lymph node failures was lower (1220 vs 1910 µm2 /s; p = .003) than non-failures. Using an ADC threshold of 1500 µm2 /s, the sensitivity, specificity, and positive and negative predictive values (PPV; NPV) were 100% (4/4), 92% (46/50), 50% (4/8), and 100% (46/46) for DWI, respectively, and 100% (3/3), 71% (22/31), 25% (3/12), and 100% (22/22) for PET/CT, respectively. CONCLUSION: Earlier DWI produced similar sensitivity and better specificity in identifying persistent neck disease as 3-month PET/CT. © 2016 Wiley Periodicals, Inc. Head Neck 39: 432-438, 2017.