The value of intravoxel incoherent motion diffusion-weighted imaging in predicting the pathologic response to neoadjuvant chemotherapy in locally advanced esophageal squamous cell carcinoma.

OBJECTIVE: To explore the value of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) for the prediction of pathologic response to neoadjuvant chemotherapy (NAC) in locally advanced esophageal squamous cell carcinoma (ESCC). MATERIAL AND METHODS: Forty patients with locally advanced ESCC who were treated with NAC followed by radical resection were prospectively enrolled from September 2015 to May 2018. MRI and IVIM were performed within 1 week before and 2-3 weeks after NAC, prior to surgery. Parameters including apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudodiffusion coefficient (D*), and pseudodiffusion fraction (f) before and after NAC were measured. Pathologic response was evaluated according to the AJCC tumor regression grade (TRG) system. The changes in IVIM values before and after therapy in different TRG groups were assessed. Receiver operating characteristic (ROC) curves analysis was used to determine the best cutoff value for predicting the pathologic response to NAC. RESULTS: Twenty-two patients were identified as TRG 2 (responders), and eighteen as TRG 3 (non-responders) in pathologic evaluation. The ADC, D, and f values increased significantly after NAC. The post-NAC D and ΔD values of responders were significantly higher than those of non-responders. The area under the curve (AUC) was 0.722 for post-NAC D and 0.859 for ΔD in predicting pathologic response. The cutoff values of post-NAC D and ΔD were 1.685 × 10-3 mm2/s and 0.350 × 10-3 mm2/s, respectively. CONCLUSION: IVIM-DWI may be used as an effective functional imaging technique to predict pathologic response to NAC in locally advanced ESCC. KEY POINTS: • The optimal cutoff values of post-NAC D and ΔD for predicting pathologic response to NAC in locally advanced ESCC were 1.685 × 10-3 mm2/s and 0.350 × 10-3 mm2/s, respectively. • Pathologic response to NAC in locally advanced ESCC was favorable in patients with post-NAC D and ΔD values that were higher than the optimal cutoff values. • IVIM-DWI can potentially be used to preoperatively predict pathologic response to NAC in esophageal carcinoma. Accurate quantification of the D value derived from IVIM-DWI may eventually translate into an effective and non-invasive marker to predict therapeutic efficacy.

MRI features in differentiating mucosal high-grade neoplasia from early invasive squamous cell cancer of the esophagus.

OBJECTIVES: To evaluate the diagnostic accuracy of unenhanced and contrast-enhanced MRI in the differentiation of mucosal high-grade neoplasia (MHN) from early invasive squamous cell cancer (EISCC) of the esophagus. METHODS: Between March 2015 and January 2019, 72 study participants with MHN (n = 46) and EISCC (n = 26) of the esophagus were enrolled in this prospective study. Postoperative histopathologic analysis was the reference standard. All participants underwent MRI (T2-multi-shot turbo spin-echo sequence (msTSE), diffusion-weighted imaging (DWI), and 3D gradient-echo-based sequence (3D-GRE)). Two radiologists, blinded to participants' data, independently evaluated MRI and assigned MR features including shape (mucosal thickening or focal mass), signal on T2-msTSE and DWI, enhancement degree (intense or slight), and enhancement pattern (homogeneous, heterogeneous, or heart-shaped). Diagnostic performance of the 5 features was compared using the chi-square test; kappa values were assessed for reader performance. RESULTS: Surgery was performed within 3.6 + 3.5 days after MR imaging. Inter-reader agreement on MR features was excellent (kappa value = 0.854, p < 0.001). All 8 mass-like MHN were "heart-shaped" in appearance. The degree of enhancement showed the best diagnosis performance in differentiating between MHN and EISCC of the esophagus. The combination of all 5 features had only borderline improved sensitivity, specificity, and AUC of 100%, 96.2%, and 0.999, respectively, which was not statistically significant compared with the degree of enhancement alone. CONCLUSIONS: MRI can differentiate MHN from EISCC in esophagus; the presence of "heart-shaped" appearance favors the diagnosis of MHN. KEY POINTS: • All 8 mass-like MHN showed a "heart-shaped" enhancement pattern which may help differentiating MHN from EISCC. • Degree of enhancement had the best diagnostic performance in differentiating between MHN and EISCC in esophagus. • The combined 5 features (shape, signal in T2-msTSE and DWI, enhancement degree, and enhancement pattern) provided sensitivity, specificity, and AUC of 100%, 96.2%, and 0.999, respectively, which was not statistically significant than tumor enhancement alone in distinguishing MHN from EISCC.

Accuracy of 3-T MRI for Preoperative T Staging of Esophageal Cancer After Neoadjuvant Chemotherapy, With Histopathologic Correlation.

OBJECTIVE: The purpose of this study was to explore the value of 3-T MRI for evaluating the preoperative T staging of esophageal cancer (EC) treated with neoadjuvant chemotherapy (NAC), with histopathologic confirmation. SUBJECTS AND METHODS: This prospective study enrolled patients for whom endoscopic biopsy showed EC and pretreatment CT showed stage cT1N+M0 or cT2-T4aN0-N3M0. All patients received two cycles of NAC (paclitaxel and nedaplatin protocol) followed by 3-T MRI and surgical resection. Readers assigned a T category on MRI, and postoperative pathologic confirmation was considered the reference standard. Interreader agreement, the diagnostic accuracy of T staging on T2-weighted turbo spin-echo (TSE) BLADE (Siemens Healthcare), contrast-enhanced StarVIBE (Siemens Healthcare), high-resolution delayed phase StarVIBE, and the combination of the three sequences were analyzed and compared with postoperative pathologic T staging. RESULTS: The study included 79 patients. Mean time between NAC and MRI was 23 days. Interreader agreements of T category assignment were excellent for T2-weighted TSE BLADE (κ = 0.810, p < 0.0001), contrast-enhanced StarVIBE (κ = 0.845, p < 0.0001), high-resolution delayed phase StarVIBE (κ = 0.897, p < 0.0001), and the combination of the three sequences (κ = 0.880, p < 0.0001). The highest accuracy for T0, T1, T2, and T4a lesions was on high-resolution delayed phase StarVIBE (96.2%, 92.4%, 91.1%, and 91.1% for reader 1; 94.9%, 89.9%, 91.1%, and 94.9% for reader 2), and the highest accuracy for T3 lesions was on T2-weighted TSE BLADE (92.4% and 94.9% for reader 1 and reader 2, respectively). Diagnostic accuracy of the combination of the three sequences was not improved compared with individual sequences. CONCLUSION: High-resolution delayed phase StarVIBE had the highest diagnostic accuracy in staging EC after NAC for all T categories except T3, for which T2-weighted TSE BLADE had the highest accuracy. Combining all three sequences did not improve diagnostic accuracy.

Comparison between free-breathing radial VIBE on 3-T MRI and endoscopic ultrasound for preoperative T staging of resectable oesophageal cancer, with histopathological correlation.

OBJECTIVES: To compare the T staging of resectable oesophageal cancer (OC) using radial VIBE (r-VIBE) and endoscopic ultrasound (EUS) with pathological confirmation of the T stage. METHODS: Forty-three patients with endoscopically proven OC and indeterminate T1/T2/T3/T4a stage by computed tomography (CT) and EUS were imaged on a 3-T magnetic resonance imaging (MRI) scanner. T stage was scored on MRI and EUS by two independent radiologists and one endoscopist, respectively, and compared with postoperative pathological findings. T staging agreement between r-VIBE and EUS with postoperative pathological T staging was analysed by a kappa test. RESULTS: EUS and pathological T staging showed agreement of 69.8% (30/43). Radial VIBE and pathological T staging agreement was 86.0% (37/43) and 90.7% (39/43) for readers 1 and 2, respectively. High accuracy for T1/T2 stage was obtained for both r-VIBE readers (90.5% and 100% for reader 1 and reader 2, respectively) and EUS reader (100%). For T3/T4, r-VIBE showed accuracy of 81.8% and 90.9% for reader 1 and reader 2, respectively, while for EUS, accuracy was only 68.2% compared with pathological T staging. CONCLUSIONS: Contrast-enhanced r-VIBE is comparable to EUS in T staging of resectable OC with stage of T1/T2, and is superior to EUS in staging of T3/T4 lesions. KEY POINTS: • Radial VIBE may be useful in preoperative T staging of OC • Accuracy of staging on r-VIBE is higher in T1/2 than in T3/4 • Accuracy of EUS was 100% and 68.2% for T1/T2 and T3/T4 stage • Inter-reader agreement of T staging for r-VIBE was good.

Predicting Parametrial Invasion in Cervical Carcinoma (Stages IB1, IB2, and IIA): Diagnostic Accuracy of T2-Weighted Imaging Combined With DWI at 3 T.

OBJECTIVE: The objective of our study was to retrospectively evaluate the efficacy of combined analysis of T2-weighted imaging and DWI in the diagnosis of parametrial invasion (PMI) in cervical carcinoma. MATERIALS AND METHODS: The clinical records of 192 patients with cervical carcinoma who met the study requirements were reviewed for this retrospective study. The signal intensities of suspicious PMI tissue were assessed on T2-weighted images, DW images, and apparent diffusion coefficient maps independently by two experienced radiologists. The radiologist observers predicted the presence of PMI by scoring T2-weighted imaging alone and then by scoring T2-weighted imaging and DWI combined. The results were compared with histopathologic findings. RESULTS: Histopathologic findings revealed PMI in 24 of 192 study subjects. In positively predicting the presence of PMI, T2-weighted imaging and DWI combined scored significantly better than T2-weighted imaging alone, as proven by high sensitivity (T2-weighted imaging alone vs T2-weighted imaging and DWI combined: observer 1, 75.0% vs 83.3% [p = 0.477]; observer 2, 66.7% vs 91.7% [p < 0.05]), high specificity (T2-weighted imaging alone vs T2-weighted imaging and DWI combined: observer 1, 84.5% vs 98.8% [p < 0.001]; observer 2, 85.7% vs 98.8% [p < 0.001]), and high accuracy (T2-weighted imaging alone vs T2-weighted imaging and DWI combined: observer 1, 83.3% vs 96.9% [p < 0.001]; observer 2, 83.3% vs 97.9% [p < 0.001]). The area under the ROC curve was also significantly higher for T2-weighted imaging and DWI combined (observer 1, 0.911; observer 2, 0.952) than for T2-weighted imaging alone (observer 1, 0.798; observer 2, 0.762). Although the interobserver agreement was good for T2-weighted imaging (κ = 0.695) and excellent for T2-weighted imaging and DWI combined (κ = 0.753), the improvement failed to achieve statistical significance (p = 0.28). CONCLUSION: Combined analysis of T2-weighted imaging and DWI enhances the accuracy of diagnosing PMI in patients with cervical cancer compared with T2-weighted imaging alone.

Effect of intravenous gadolinium-DTPA on diffusion-weighted imaging of brain tumors: a short temporal interval assessment.

PURPOSE: To determine the effect of intravenous administration of gadolinium (Gd) contrast medium (Gd-DTPA) on diffusion-weighted imaging (DWI) for the evaluation of normal brain parenchyma vs. brain tumor following a short temporal interval. MATERIALS AND METHODS: Forty-four DWI studies using b values of 0 and 1000 s/mm(2) were performed before, immediately after, 1 min after, 3 min after, and 5 min after the administration of Gd-DTPA on 62 separate lesions including 15 meningioma, 17 glioma and 30 metastatic lesions. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and apparent diffusion coefficient (ADC) values of the brain tumor lesions and normal brain tissues were measured on pre- and postcontrast images. Statistical analysis using paired t-test between precontrast and postcontrast data were obtained on three brain tumors and normal brain tissue. RESULTS: The SNR and CNR of brain tumors and the SNR of normal brain tissue showed no statistical differences between pre- and postcontrast (P > 0.05). The ADC values on the three cases of brain tumors demonstrated significant initial increase on the immediate time point (P < 0.01) and decrease on following the 1 min time point (P < 0.01) after contrast. Significant decrease of ADC value was still found at 3min and 5min time point in the meningioma group (P < 0.01) with gradual normalization over time. The ADC values of normal brain tissues demonstrated significant initial elevation on the immediately postcontrast DWI sequence (P < 0.01). CONCLUSION: Contrast medium can cause a slight but statistically significant change on the ADC value within a short temporal interval after the contrast administration. The effect is both time and lesion-type dependent.

Comparison of computed tomography versus magnetic resonance imaging in assessing radiofrequency ablation margins after radiofrequency ablation in patients with hepatocellular carcinomas.

OBJECTIVE: To assess the diagnostic value of magnetic resonance imaging (MRI) in the follow-up of patients with hepatocellular carcinomas treated with radiofrequency ablation (RFA) and to compare it with that of computed tomography (CT). METHODS: From December 2009 to September 2011, 40 patients (47 hepatocellular carcinomas) were treated with RFA after transcatheter arterial chemoembolization and underwent MRI and CT for follow-up. RFA margins were assessed on a five-point scale with receiver operating characteristic curve analysis. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were evaluated. RESULTS: The interobserver agreement rate for MRI was significantly higher (Kappa=0.935) than for CT (Kappa=0.714; P < 0.05). The scores of 1 and 5 points for MRI, which confirms the presence or absence of residual tumor, accounted for 89.4% (84/94), while for CT accounting for only 31.9% (30/94). The area under the receiver operating characteristic curve of MRI was significantly higher than that of CT (P < 0.05), as were the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of detection rate (mean, 100%, 96.4%, 76.9%, 100%, and 96.8% for MRI, respectively, vs. 30.0%, 57.1%, 10.3%, 87.7%, and 63.8% for CT). CONCLUSION: MRI is superior to CT in assessing the RFA margins in terms of the diagnostic accuracy and detection rate .

A prospective analysis of the diagnostic accuracy of 3 T MRI, CT and endoscopic ultrasound for preoperative T staging of potentially resectable esophageal cancer.

BACKGROUND: Patients with esophageal cancer (EC) undergo endoscopic ultrasound and CT based cancer staging. Recent technical developments allow improved MRI quality with diminished motion artifact that may allow MRI to compare favorable to CT for noninvasive staging. Hence the purpose of the study was to assess image quality and diagnostic accuracy of 3 T MRI versus CT and EUS for preoperative T-staging of potentially resectable esophageal cancer. METHODS: Between October-2014 and December-2017, esophageal cancer patients with T-staging by EUS were enrolled in this prospective study. Post-operative histopathologic T-staging was the reference standard. All participants underwent MRI [T2- multi-shot turbo spin echo sequence (msTSE), diffusion-weighted imaging (DWI), and 3D gradient-echo based sequence (3D-GRE)] and CT [non-contrast and multiphase contrast-enhanced CT scanning] 5.6 + 3.6 days after endoscopy. Surgery was performed within 3.6 + 3.5 days after imaging. Two blinded endoscopists (reader 1 and 2) and radiologists (reader 3 and 4) independently evaluated EUS and CT/MRI, respectively. Considering the clinical relevance, patients were dichotomized into early (T1 and T2) vs late (T3 and T4) stage cancer before assessment. For statistical purpose, the binary decision was defined as the ability of the imaging technique to diagnose early stage/not early stage esophageal cancer. Diagnostic performance of EUS, MRI and CT was compared using McNemar's test with Bonferroni correction; kappa values were assessed for reader performance. RESULTS: 74 study participants (60 ± 8 yrs.; 56 men) with esophageal cancer were evaluated, of whom 85%(63/74) had squamous cell carcinoma, 61%(45/74) were at early stage and 39%(29/74) were at late stage cancer, as determined by histopathology. Intra- and Inter-reader agreement for pre-operative vs post-operative T-staging was excellent for all imaging modalities. Compared to CT, MRI showed significantly higher accuracy for both the readers (reader3: 96% vs 82%, p = 0.0038, reader4: 95% vs 80%, p = 0.0076, for MRI vs CT, respectively). Further, MRI outperformed EUS with higher specificity (reader 1 vs 3: 59% vs 93%, p = 0.0015, reader 2 vs 4: 66% vs 93%, p = 0.0081, for EUS vs MRI respectively), and accuracy (reader 1 vs 3: 81% vs 96%, p = 0.0022, reader 2 vs 4: 85% vs 95%, p = 0.057, for EUS vs MRI, respectively). CONCLUSION: For resectable esophageal cancer, MRI had better diagnostic performance for tumor staging compared to CT and EUS. TRIAL REGISTRATION: ChiCTR, ChiCTR-DOD, Registered 2nd October 2014, http://www.chictr.org.cn/showproj.aspx?proj=9620.

Arterial Phase with CAIPIRINHA-Dixon-TWIST (CDT)-Volume-Interpolated Breath-Hold Examination (VIBE) in Detecting Hepatic Metastases.

PURPOSE: To evaluate lesion enhancement performance of Multi-Arterial CAIPIRINHA-Dixon-TWIST-Volume-Interpolated Breath-Hold Examination (MA-CDT-VIBE) for the detection of hepatic metastases. MATERIALS AND METHODS: Thirty-one patients with suspicious hepatic metastases were enrolled in this retrospective study. Two independent radiologists scored visualization of each lesion on a scale of 1 (poor visualization) to 11 (excellent visualization) on 11 sets of images. These included 6 hepatic arterial sub-phases acquired in one breath-hold, 1 series of the mean of 6 hepatic arterial sub-phases, 3 subtracted arterial sub-phases, and 1 portal venous phase. The phases with good (score 8-10) and excellent (score 11) lesion visualization were identified, and the number of lesions seen on each of these phases was compared to the number of lesions that was seen best on the equivalent-to-conventional single arterial phase as well as to those that were see best on the mean of 6 hepatic arterial sub-phases. Inter-reader agreement was also calculated. RESULTS: The MA-CDT-VIBE was successfully acquired in 25 patients with hypervascular metastases (96 lesions) and 6 patients with hypovascular metastases (13 lesions). In case of hypervascular metastases, the 6th/6 arterial sub-phase had excellent lesion visualization (sore of 11) in 56 and 44 lesions for the 2 readers, respectively. Good lesion visualization (score of 8-10) was recorded in 5th/6 arterial subphases, in 81 and 67 lesions for the 2 readers, respectively. In case of hypovascular metastases, the portal venous phase had excellent lesion visualization (sore of 11) in all 13 lesions for the 2 readers. Good lesion visualization (score of 8-10) was recorded in 12 and 13 lesions on the 5th/6 and 6th/6 arterial subphases, respectively. More hypervascular lesions scored good (score of 8-10) and excellent (score of 11) on the 5th/6 and 6th/6 phases of MA-CDT-VIBE compared with the equivalent-to-conventional single arterial phase (3rd/6) and the set with mean of 6 hepatic arterial sub-phases. The results were statistically significant (t test, P<.0001). Inter-reader agreement was good for hypervascular lesions (kappa=0.627, P<.0001) and excellent for hypovascular lesions (kappa=1.0, P<.0001), respectively. CONCLUSIONS: The MA-CDT-VIBE improves lesion conspicuity by providing a wide observation window for hypervascular lesions. For hypovascular lesions, the advantage of multiple arterial sub-phases over the portal venous phase is not apparent.

Preoperative T Staging of Potentially Resectable Esophageal Cancer: A Comparison between Free-Breathing Radial VIBE and Breath-Hold Cartesian VIBE, with Histopathological Correlation.

PURPOSE: To compare the T staging of potentially resectable esophageal cancer using free-breathing radial VIBE (r-VIBE) and breath-hold Cartesian VIBE (C-VIBE), with pathologic confirmation of the T stage. MATERIALS AND METHODS: Fifty patients with endoscopically proven esophageal cancer and indeterminate T1/T2/T3 stage by CT scan were examined on a 3-T scanner. The MRI protocol included C-VIBE at 150 seconds post-IV contrast, immediately followed by a work-in-progress r-VIBE with identical spatial resolution (1.1 mm × 1.1 mm × 3.0 mm). Two independent readers assigned a T stage on MRI according to the 7th edition of UICC-AJCC TNM Classification, and postoperative pathologic confirmation was considered the gold standard. Interreader agreement was also calculated. RESULTS: The T staging agreement between both VIBE techniques and postoperative pathologic T staging was 52% (26/50) for C-VIBE, 80% (40/50) for r-VIBE for reader 1, and 50% (25/50), 82% (41/50) for reader 2, respectively. For the esophageal cancer with invading lamina propria, muscularis mucosae, or submucosa (T1 stage), r-VIBE achieved 86% (12/14) agreement for both readers 1 and 2. For invasion of muscularis propria (T2 stage), r-VIBE achieved 83% (25/30) for both readers 1 and 2, whereas for the invasion of adventitia (T3 stage), r-VIBE could only achieve agreement in 50% (3/6) and 67% (4/6) for readers 1 and 2, respectively. CONCLUSION: Contrast-enhanced free-breathing r-VIBE is superior to breath-hold CVIBE in T staging of potentially resectable esophageal cancer, especially for T1 and T2.

Improved Detection of Recurrent Hepatocellular Carcinomas in Arterial Phase With CAIPIRINHA-Dixon-TWIST-Volumetric Interpolated Breath-Hold Examination.

PURPOSE: The aim of this study was to assess the detection rate of recurrent hepatocellular carcinoma (HCC) in arterial phase using multiarterial CAIPIRINHA-Dixon-TWIST-VIBE (MA-CDT-VIBE). MATERIALS AND METHODS: Fifty-eight patients with possible recurrence of HCC were retrospectively included in this cohort. Patients were scanned with a prototype dynamic contrast-enhanced breath-hold CDT-VIBE sequence, which included 6 arterial subphases with a temporal resolution of 2.64 seconds on a 3 T scanner. Absence and presence of recurrence was documented by consensus of 2 experienced radiologists using magnetic resonance imaging multiphase imaging and follow-up evaluation. The third of 6 arterial subphases was considered the equivalent-to-conventional single arterial phase from the contrast bolus timing perspective. The detection rate of recurrent HCCs in arterial phase by another 2 independent experienced readers was compared for all 6 arterial subphases of MA-CDT-VIBE and the equivalent-to-conventional single arterial phase. Interreader agreement was also calculated. RESULTS: Of the 55 patients reviewed, 46 patients (201 lesions) had recurrent HCC and 9 patients had no recurrence. There was an excellent interreader agreement for both MA-CDT-VIBE (κ = 1.000, P < 0.0001) and the equivalent-to-conventional single arterial phase (κ = 0.850, P < 0.0001). MA-CDT-VIBE showed the detection rate of 100% for all lesions with the diameter of less than 1 cm, 1 to 2 cm, and more than 2 cm. The equivalent-to-conventional single arterial phase resulted in the detection rate of 81.1% and 83.1% for all recurrent HCCs by the 2 readers, respectively, with 78.7% and 83.6% for lesions measuring less than 1 cm, 79.2% and 81.2% for lesions measuring 1 to 2 cm, and 89.7% and 87.2% for lesions measuring more than 2 cm. CONCLUSIONS: Compared with the equivalent-to-conventional single arterial phase, MA-CDT-VIBE with 6 arterial subphases demonstrated higher detection rate of recurrent HCCs in arterial phase and provided a wider arterial observation window, especially for recurrent HCCs less than 2 cm in diameter.