Dual-phase Contrast-enhanced CT Research Articles

Intraprocedural C-arm dual-phase cone-beam enhancement patterns correlate with tumor absorbed dose after radioembolization.

Recent studies have shown a clear relationship between absorbed dose and tumor response to treatment after hepatic radioembolization. These findings help to create more personalized treatment planning and dosimetry. However, crucial to this goal is the ability to predict the dose distribution prior to treatment. The microsphere distribution is ultimately determined by (i) the hepatic vasculature and the resulting blood flow dynamics and (ii) the catheter position. To show that pretreatment, intra-procedural imaging of blood flow patterns, as quantified by catheter-directed intra-arterial contrast enhancement, correlate with posttreatment microsphere accumulation and, consequently, absorbed dose. Patients who participated in a clinical trial (NCT01177007) and for whom both a pretreatment dual-phase contrast-enhanced cone-beam CT (CBCT) and a posttreatment 90Y PET/CT scan were available were included in this retrospective study. Tumors and perfused volumes were manually delineated on the CBCT by an experienced radiologist. The mean, sum, and standard deviation of the voxels in each volume were recorded. The delineations were transferred to the PET-based absorbed dose maps by coregistration of the corresponding CTs. Linear multiple regression was used to correlate pretreatment CBCT enhancement to posttreatment 90Y PET/CT-based absorbed dose in each region. Leave-one-out cross-validation and Bland-Altman analyses were performed on the predicted versus measured absorbed doses. Nine patients, with a total of 23 tumors were included. All presented with hepatocellular carcinoma (HCC). Visually, all patients had a clear correspondence between CBCT enhancement and absorbed dose. The correlation between CBCT enhancement and posttherapy absorbed tumor dose based was strong (R2=0.91), and moderate for the non-tumor liver tissue (R2=0.61). Limits of agreement were approximately ±55 Gray for tumor tissue. There is a linear relationship between pretreatment blood dynamics in HCC tumors and posttreatment absorbed dose, which, if shown to be generalizable, allows for pretreatment tumor absorbed dose prediction.

Renal venous density in the arterial phase of contrast-enhanced CT predicts prognosis in septic shock.

To evaluate a series of vascular parameters derived from abdominal dual-phase contrast-enhanced CT as predictors of 14-day mortality and AKI within 7 days in septic shock. 144 patients with septic shock and 60 negative cases were included. The vascular parameters from CT were measured and calculated, including aortic density in arterial (Dena-A) and venous phase (Dena-V), renal vein density in arterial (Denrv-A) and venous phase (Denrv-V), and renal vein-to-aortic density ratio in arterial (DenRrv/a-A) and venous phase (DenRrv/a-V). The parameters were compared between patients and controls, and between patients with different clinical outcomes, and assessed for predictive value of 14-day mortality and AKI within 7 days. Patients with septic shock presented significantly lower Denrv-A (p < 0.001) and DenRrv/a-A (p = 0.002) levels than the controls. In the septic shock group, patients who died had significantly lower Denrv-A (p = 0.001) and lower DenRrv/a-A (p < 0.001) than those who survived. Patients who developed AKI had significantly lower Denrv-A (p < 0.001) and DenRrv/a-A (p = 0.011) than those who did not. Multivariate analysis suggested DenRrv/a-A as an independent predictor of 14-day mortality (OR 0.012; 95% confidence interval [CI]:0.002,0.086; p < 0.001) and Denrv-A as an independent predictor of AKI (OR 0.989;95% CI:0.982,0.997; p = 0.006). In septic shock, significant decreases in Denrv-A and DenRrv/a-A were associated with the onset of AKI and predicted higher 14-day mortality. The renal vein density and renal vein-aortic density ratio in arterial phase of dual-phase contrast-enhanced CT may serve as good predictors of AKI and mortality in septic shock.

Adrenal heterogeneity in the arterial phase of contrast-enhanced CT predicts prognosis in septic shock: comparison with hollow adrenal gland sign.

To evaluate the prognostic value of adrenal heterogeneity in the arterial phase in patients with septic shock, comparatively to the hollow adrenal gland sign (HAGS). Totally 84 consecutive patients with septic shock (group S) were assessed retrospectively, and abdominal dual-phase contrast-enhanced CT was performed after the diagnosis of septic shock within one week. The patients were divided into two groups according to clinical outcome, including the survivor (group A, 41 cases) and death (group B, 43 cases) groups. Fifty negative cases were matched as the control (group C). The incidence of the HAGS in patients with septic shock (group S) was statistically analyzed. The average values of left adrenal density (Den-A and Den-V) and their standard deviations (SDDen-A and SDDen-V) in dual phases were measured. The above parameters were compared between groups A and B as well as with group C. The parameters were assessed for their predictive values of mortality in septic shock, comparatively to the HAGS. Compared with group C, group S presented significantly higher Den-A (P = 0.003) and SDDen-A (P < 0.001). There were significantly higher SDDen-A (P < 0.001) in group B compared with group A. The incidence of the HAGS was about 27.4% (23/84) in group S. The sensitivity and specificity in predicting poor prognosis in patients with septic shock were 78% and 85% with SDDen-A, at a cut-off value of 28.64, respectively. The sensitivity and specificity were 41% and 88% for the HAGS, respectively. The area under ROC curve (AUC) was significantly greater for SDDen-A compared with the HAGS (0.820 vs. 0.670, P < 0.001). Adrenal heterogeneity in the arterial phase can predict prognosis in patients with septic shock; the larger the SDDen-A, the poorer the prognosis. The predictive efficiency of adrenal heterogeneity in the arterial phase is better than the HAGS.

CT findings in renovascular injuries following abdominal trauma: a pictorial review.

Renal vascular injuries are more devastating than parenchymal injuries alone, thus account for higher injury grade and require prompt recognition. Revised AAST organ injury scale (OIS) for renal trauma has incorporated CT-diagnosed vascular injuries into renal injury grading which includes pseudoaneurysm and arteriovenous fistula, along with addition of some new descriptors of renovascular injury. Dual-phase contrast-enhanced CT (with both arterial and venous phase) can easily pick up renovascular injuries and is the modality of choice for imaging renovascular trauma. Radiologist should be well versed with the imaging findings of renovascular injuries so that accurate injury grading can be done and further management can be planned at the earliest.

Dual-phase contrast-enhanced CT evaluation of dural arteriovenous fistula in patients with pulsatile tinnitus as an initial symptom

PurposeIntracranial dural arteriovenous fistula (DAVF) can cause pulsatile tinnitus (PT). The purpose of this study was to investigate the diagnostic performance of dual-phase contrast-enhanced CT (DP-CECT) for DAVF in PT patients compared with digital subtraction angiography (DSA). MethodFrom February 2015 to April 2021, PT patients undergoing routine DSA examination were prospectively analyzed. Patients with and without DAVF diagnosed by DSA were included. In DP-CECT, the radiological signs related to DAVF were assessed as follows: asymmetric external carotid artery (ECA) branches, asymmetric enhancement of intracranial or extracranial veins, asymmetric venous collaterals in extracranial space, and shaggy tentorium or venous sinus on CTA; asymmetric enhancement of intracranial or extracranial veins on CTV; numerous transcalvarial channels and asymmetric size of foramen spinosum on high-resolution CT (HRCT). Results253 PT patients receiving DSA were enrolled, and these patients had previously been screened by DP-CECT. Forty-six patients were diagnosed as DAVF by DSA. Therefore, the prevalence of DAVF was 18% (46/253) in patients with PT as the initial symptom. The sensitivity and specificity of DP-CECT for diagnosis of DAVF were 96% and 100%. The sensitivity of individual CTA signs ranged from 65% to 93%, and specificities ranged from 83% to 100%. The sensitivity of CTV sign was 80%, and specificity was 100%. The sensitivity of individual HRCT signs ranged from 48 to 52% and specificities from 61 to 100%. ConclusionsDAVF is not rare in patients with PT as the initial symptom. DP-CECT can be used for screening DAVF in patients with PT.

Value of the application of enhanced CT radiomics and machine learning in preoperative prediction of microvascular invasion in hepatocellular carcinoma

Objective: To explore the value of machine learning models in preoperative prediction of microvascular invasion (MVI) in hepatocellular carcinoma (HCC) based on dual-phase contrast-enhanced CT radiomics features. Methods: The data of 148 patients [106 males and 42 females, with an average age of (58±11) years] with HCC confirmed by pathology in the First Affiliated Hospital of Soochow University from January 2015 to May 2020 were retrospectively analyzed, including 88 cases of positive MVI and 60 cases of negative MVI. According to the ratio of 7∶3, the patients were randomly divided into the training and validation sets, respectively. The three-dimensional (3D) radiomics features of HCC in arterial phase (AP) and portal venous phase (PP) were extracted by MaZda software, and the optimal feature subset was obtained by combining three feature selection methods (FPM method) and Lasso regression. Then, six machine learning methods were used to build the prediction models. Receiver operating characteristic (ROC) curves were drawn to evaluate the prediction ability of the aforementioned models, and the area under the curve (AUC), accuracy, sensitivity and specificity were calculated. Results: Radiomics features of HCC in AP and PP were extracted by MaZda software, with 239 in each phase. There were 7 optimal features in AP and 14 optimal features in PP selected by FPM method and Lasso regression, respectively. The AUCs of decision tree, extreme gradient boosting, random forest, support vector machine (SVM), generalized linear model, and neural network based on the 7 optimal features in AP in the validation set were 0.736, 0.910, 0.913, 0.915, 0.897, 0.648, respectively. The SVM had the highest AUC in the validation set, with the accuracy, sensitivity and specificity of 95.35%, 95.83% and 94.74%, respectively. Likewise, the AUCs of machine learning models in prediction of MVI in HCC based on the 14 optimal features in PP in the validation set were 0.873, 0.876, 0.913, 0.859, 0.877, 0.834, respectively, and there were no significant differences (all P>0.05). The random forest had the highest AUC in the validation set, with the accuracy, sensitivity and specificity of 90.70%, 87.50% and 94.74%, respectively. Conclusion: Machine learning models based on dual-phase enhanced CT radiomics features can be used in preoperative prediction of MVI in HCC, particularly the SVM and random forest models have high prediction efficiency.

Adding Delayed Phase Images to Dual-Phase Contrast-Enhanced CT Increases Sensitivity for Small Pancreatic Ductal Adenocarcinoma.

BACKGROUND. Contrast-enhanced CT performed for pancreatic ductal adeno-carcinoma (PDAC) detection traditionally uses a dual-phase (pancreatic and portal venous) protocol. However, PDAC may exhibit isoattenuation in these phases, hindering detection. OBJECTIVE. The purpose of this study was to assess the impact on diagnostic performance in detection of small PDAC when a delayed phase is added to dual-phase contrast-enhanced CT. METHODS. A database of 571 patients who underwent triple-phase (pancreatic, portal venous, and delayed) contrast-enhanced MDCT between January 2017 and March 2020 for suspected pancreatic tumor was retrospectively reviewed. A total of 97 patients had pathologically confirmed small PDAC (mean size, 22 mm; range, 7-30 mm). Twenty control patients had no pancreatic tumor suspected on CT, on initial MRI and follow-up CT, or on MRI after 12 months or longer. Three radiologists independently reviewed dual-phase and triple-phase images. Two additional radiologists assessed tumors' visual attenuation on each phase, reaching consensus for differences. Performance of dual- and triple-phase images were compared using ROC analysis, McNemar test, and Fisher exact test. RESULTS. AUC was higher (p < .05) for triple-phase than dual-phase images for all observers (observer 1, 0.97 vs 0.94; observer 2, 0.97 vs 0.94; observer 3, 0.97 vs 0.95). Sensitivity was higher (p < .001) for triple-phase than dual-phase images for all observers (observer 1, 74.2% [72/97] vs 59.8% [58/97]; observer 2, 88.7% [86/97] vs 71.1% [69/97]; observer 3, 86.6% [84/97] vs 72.2% [70/97]). Specificity, PPV, and NPV did not differ between image sets for any reader (p ≥ .05). Seventeen tumors showed pancreatic phase visual isoattenuation, of which nine showed isoattenuation and eight hyperattenuation in the delayed phase. Of these 17 tumors, 16 were not detected by any observer on dual-phase images; of these 16, six were detected by at least two observers and five by at least one observer on triple-phase images. Visual attenuation showed excellent interob-server agreement (κ = 0.89-0.96). CONCLUSION. Addition of a delayed phase to pancreatic and portal venous phase CT increases sensitivity for small PDAC without loss of specificity, partly related to delayed phase hyperattenuation of some small PDACs showing pancreatic phase isoattenuation. CLINICAL IMPACT. Addition of a delayed phase may facilitate earlier PDAC detection and thus improved prognosis.

Texture analysis of dual-phase contrast-enhanced CT in the diagnosis of cervical lymph node metastasis in patients with papillary thyroid cancer.

Computed tomography texture analysis (CTTA) provides objective and quantitative information regarding tumor heterogeneity beyond visual inspection. However, no study has yet used CTTA to differentiate metastatic from non-metastatic cervical lymph node in patients with papillary thyroid cancer (PTC). To evaluate the value of texture analysis of dual-phase contrast-enhanced CT images in diagnosing cervical lymph node metastasis in patients with PTC. Metastatic (n = 27) and non-metastatic (n = 32) cervical lymph nodes were analyzed retrospectively. Texture analyses were performed on both arterial (A) and venous (V) phase CT images. Texture parameters, including mean gray-level intensity, skewness, kurtosis, entropy, and uniformity, were obtained and compared between groups. Receiver operating characteristic (ROC) curves analyses and multivariate logistic regression analysis were used in our study. Metastatic lymph nodes showed significantly higher A-mean gray-level intensity, A-entropy, and lower A-kurtosis and V-kurtosis (all P < 0.001) than non-metastatic mimics. The ROC curve analyses indicated that A-kurtosis demonstrated an optimal diagnostic area under the curve (AUC; 0.884) and specificity (92.59%), while the A-mean gray-level intensity showed optimal diagnostic sensitivity (90.62%). Multivariate logistic regression analysis showed that A-mean gray-level intensity (P = 0.006, odds ratio [OR] = 24.297) and V-kurtosis (P = 0.014, OR = 19.651) were the independent predictor for metastatic cervical lymph node. Dual-phase contrast-enhanced CCTA-especially A-mean gray-level intensity and V-kurtosis-may have the potential to diagnose metastatic cervical lymph node in patients with PTC.

The hollow adrenal gland sign: a newly described enhancing pattern of the adrenal gland on dual-phase contrast-enhanced CT for predicting the prognosis of patients with septic shock.

To investigate the incidence, CT appearance, and implication for prognosis of the hollow adrenal gland sign (HAGS). A total of 194 patients with septic shock and 24 patients with hemorrhagic shock (as control group) were retrospectively included in this study and the patients with septic shock were further divided into four subgroups (digestive tract diseases, DTD, n = 49; biliary and pancreatic diseases, BPD, n = 41; postsurgical infection, PI, n = 64; and other diseases, OD, n = 40). All patients underwent a dual-phase contrast-enhanced CT within 1week after diagnosis. CT findings and clinical records were reviewed. If in the arterial phase the central zone of adrenal gland showed temporally much lower attenuation than the peripheral zone, it was defined as HAGS positive. The incidence of the HAGS in patients with septic shock and hemorrhagic shock, the demographic features, and mortality between HAGS-positive and HAGS-negative patients in each group were respectively compared. The incidence of the HAGS in the septic shock group was nearly 30%, while it was 0 in the hemorrhagic shock group. There was no significant difference in age or gender between HAGS-positive and HAGS-negative patients in all groups, while the mortality of HAGS-positive patients was significantly higher than that of HAGS-negative patients in each group (p < 0.05). The concordance correlation coefficient value showed excellent reproducibility of the two observers (κ = 0.977). The HAGS is specific and common on dual-phase contrast-enhanced CT in patients with septic shock and predicts a poor prognosis. • The hollow adrenal gland sign (HAGS) newly described in this study is a special enhancing pattern of adrenal gland on dual-phase contrast-enhanced CT in patients with septic shock. • The HAGS is characterized by the much lower-attenuated central zone of the adrenal gland in arterial phase and it showed excellent reproducibility between different observers. • The HAGS is specific and common on dual-phase contrast-enhanced CT in patients with septic shock and predicts a poor prognosis.

Preoperative assessment of the ureter with dual-phase contrast-enhanced computed tomography for lateral lumbar interbody fusion procedures.

Performing the minimally invasive lateral lumbar interbody fusion (LIF), such as the extreme lateral interbody fusion (XLIF) and oblique lateral interbody fusion (OLIF), through a retroperitoneal approach has become increasingly popular. Although urological injury is a major complication of LIF, the anatomical location of the ureter and its risk of injury have not been assessed. The purpose of this study was to evaluate the efficacy of dual-phase contrast-enhanced computed tomography for assessing the location of the ureter and risk of its injury in consecutive LIF cases. 27 cases (12 men and 15 women) were enrolled in the study. Dual-phase contrast-enhanced CT was performed preoperatively, and the risk of ureteral injury was assessed. The location of the ureter was classified using the psoas muscle and vertebral body as reference structures for OLIF and XLIF procedures, respectively. During the OLIF procedures, the location of the ureter was additionally assessed with direct vision and manual palpation in all cases. Simultaneously, potential vascular anomalies were assessed with both 3D and axial images of CT. A total of 125 among 162 ureters, excluding 13 with insufficient enhancement and 24 (44.4%) within the kidney at the L2-L3 level, were assessed preoperatively; 113 ureters (90.4%) were classified as anatomically close to the surgical corridor for OLIF, and 20 ureters (16.0%) as having a potential risk of injury during XLIF. In one case, OLIF was converted to a conventional posterior procedure because of a vascular anomaly. Intraoperative findings showed that ureters moved anteriorly with the peritoneum in all cases, as assessed by manual palpation under direct vision. Dual-phase contrast-enhanced CT is useful in assessing the location of the ureter, kidney, and vascular structures simultaneously. Both OLIF and XLIF have a potential risk of urological injury.

Temporal Bone Pneumatization and Pulsatile Tinnitus Caused by Sigmoid Sinus Diverticulum and/or Dehiscence.

Background. Although air cells within temporal bone may play an important role in the transmission of pulsatile tinnitus (PT) noise, it has not been studied systematically. Purpose. To evaluate the difference in temporal bone pneumatization between PT patients with sigmoid sinus diverticulum and/or dehiscence (SSDD) and healthy people. Material and Methods. A total of 199 unilateral persistent PT patients with SSDD and 302 control subjects underwent dual-phase contrast-enhanced CT (DP-CECT), to assess the grade of temporal bone pneumatization in each ear. Results. In the bilateral temporal bone of 302 controls, 16 ears were grade I, 53 were grade II, 141 were grade III, and 394 were grade IV. Among the affected ears of 199 PT cases, 1 ear was grade I, 18 were grade II, 53 were grade III, and 127 were grade IV. There was no significant difference in the pneumatization grade between the affected PT ear and either ear in the healthy subjects (p > 0.05). Conclusion. Although air cells within the temporal bone are an important factor in the occurrence of PT, its severity does not differ significantly from the pneumatization of healthy people.

Preoperative dual-phase 3D CT angiography assessment of the right hepatic artery before gastrectomy

In the current study, we evaluated the efficacy of dual-phase three-dimensional (3D) CT angiography (CTA) in the assessment of the vascular anatomy, especially the right hepatic artery (RHA), before gastrectomy. The study initially included 714 consecutive patients being treated for gastric cancer. A dual-phase contrast-enhanced CT scan using 32-multi detector-row CT was performed for all patients. Among the 714 patients, 3D CTA clearly identified anomalies with the RHA arising from the superior mesenteric artery (SMA) in 49 cases (6.9 %). In Michels' classification type IX, the common hepatic artery (CHA) originates only from the SMA. Such cases exhibit defective anatomy for the CHA in conjunction with the celiac-splenic artery system, resulting in direct exposure of the portal vein beneath the #8a lymph node station, which was retrospectively confirmed by video in laparoscopic gastrectomy cases. Fused images of both 3D angiography and venography were obtained, and could have predicted the risk preoperatively, and the surgical finding confirmed its usefulness. Preoperative evaluations using 3D CTA can provide more accurate information about the vessel anatomy. The fused images from 3D CTA have the potential to reduce the intraoperative risks for injuries to critical vessel, such as the portal vein, during gastrectomy.

Monitoring Response to Antiangiogenic Treatment and Predicting Outcomes in Advanced Hepatocellular Carcinoma Using Image Biomarkers, CT Perfusion, Tumor Density, and Tumor Size (RECIST)

Our aim was to investigate the hypothesis that the CT perfusion (CTP) is a more sensitive image biomarker when compared with tumor burden (Response Evaluation Criteria in Solid Tumors [RECIST]) and tumor density (HU) for monitoring treatment changes and for predicting long-term outcome in advanced hepatocellular carcinoma (HCC) treated with a combination of antiangiogenic treatment and chemotherapy. In this phase II clinical trial, 33 patients with advanced HCC were enrolled and 23 were included in the current study. A diagnostic dual-phase contrast-enhanced CT and perfusion CT was performed at baseline and days 10 to 12 after initiation of antiangiogenic treatment (Bevacizumab). The patients subsequently received bevacizumab in combination with gemcitabine and oxaliplatin (GEMOX-B) and contrast-enhanced CT was performed at the end of treatment (after completing 3 cycles of GEMOX-B chemotherapy) and after every 8 week until there was evidence of disease progression or intolerable toxicity. The CTP protocol included a targeted dynamic cine acquisition for 25 to 30 seconds after 50 to 70 mL of iodinated contrast media injection at 5 to 7 mL/s. The CTP parameters were compared with tumor size (according to Response Evaluation Criteria in Solid Tumors, RECIST 1.1) and density measurements (HU) before and after treatment and correlated with patient's outcome in groups with and without tumor thrombus. A one-sided P value was calculated and the Bonferroni correction was used to address the issue of multiple comparisons. On days 10 to 12 after initiation of bevacizumab, significant decrease in CTP parameters was noted (P < 0.005). There was a mild reduction in mean tumor density (P = 0.016) without any significant change in mean tumor size. Tumors with higher baseline mean transit time values on CTP correlated with favorable clinical outcome (partial response and stable disease) and had better 6 months progression-free survival (P = 0.002 and P = 0.005, respectively). The baseline transfer constant (Ktrans) of responders (1425.19 ± 609.47 mL/1000 mL/min) was significantly higher than that of nonresponders (935.96 ± 189.47 mL/1000 mL/min). The tumor thrombus in the portal vein demonstrated baseline perfusion values and post-treatment change values similar to the HCC. In advanced HCC, CTP is a more sensitive image biomarker for monitoring early antiangiogenic treatment effects as well as in predicting outcome at the end of treatment and progression-free survival as compared with RECIST and tumor density.

Does the interval from imaging to operation affect the rate of unanticipated metastasis encountered during operation for pancreatic adenocarcinoma?

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a propensity for early metastasis that is often encountered unexpectedly at operation. Our objective was to examine the effect of the time interval between preoperative imaging and attempted resection and the venue in which imaging was performed on the frequency of unanticipated metastasis (UM) encountered at operation. We hypothesize that imaging obtained locally at our hospital and within 4 weeks of operation will result in a lesser frequency of UM encountered at operation. Between January 2004 and December 2009, records of patients undergoing planned pancreatic resection for PDAC at a high volume pancreatic surgery center were compiled. Exclusion criteria included neoadjuvant therapy, prior pancreatic resection, or evidence of metastasis on imaging. Review and analysis of clinical, radiographic, operative, and pathologic data were undertaken. Frequency of UM and outcome of resection was compared with the interval between most recent cross-sectional imaging (dual-phase contrast-enhanced CT or MRI) and operation defined as imaging-to-operation interval (IOI). Four-hundred eighty-seven patients met eligibility requirements for the study: 431 (88%) proximal and 56 (12%) distal PDAC. 202 (41%) patients had their most recent imaging performed at an outside institution, and no difference in the rates of UM was observed whether imaging was conducted at our institution or at an outside institution (P > .05). Of 329 with complete imaging information for analysis, UM were discovered in 60 (18%): 52 (18%) of 293 proximal PDAC and 8 (22%) of 36 distal PDAC. In proximal PDAC, there was a linear relationship in the frequency of UM as a function of the weekly IOI (R(2) = .99; P = .006). For distal PDAC, no significant difference in the frequency of UM as a function of IOI was observed. For proximally located PDAC, the frequency of UM increases with greater imaging-to-operation interval. Performing imaging at a high volume, pancreatic surgery center compared with elsewhere was not associated with a decrease in the rate of UM. Obtaining timely diagnostic imaging for proximal PDAC may improve the accuracy of preoperative staging, and thereby reduce the number of operations not producing oncologic benefit.

Dual-Phase 3D CT Angiography During a Single Breath-Hold Using 16-MDCT: Assessment of Vascular Anatomy Before Laparoscopic Gastrectomy

In this study, we evaluated the efficacy of dual-phase 3D CT angiography (CTA) during a single breath-hold using 16-MDCT in the assessment of vascular anatomy before laparoscopic gastrectomy. The study involved 20 consecutive patients (10 men, 10 women; mean age, 59 years) scheduled for laparoscopic gastrectomy for the treatment of early gastric cancer. A dual-phase contrast-enhanced CT scan using 16-MDCT was obtained before laparoscopic gastrectomy. After rapid infusion of a nonionic contrast agent, arterial and venous phase scans were obtained serially with an interval of 15 sec during a single breath-hold of 31 sec. Three-dimensional CTA images in the arterial phase (3D CT arteriography) and venous phase (3D CT venography) were individually reconstructed using the volume-rendering technique, and then the images were fused together. We evaluated the detectability of the celiac trunk, left gastric artery (LGA), right gastric artery (RGA), left gastric coronary vein (LCV), Henle's gastrocolic trunk, right gastroepiploic vein (RGEV), and accessory right colic vein on 3D CTA to compare with surgical findings. In all 20 patients, 3D CT arteriography and venography clearly showed the celiac trunk, LGA, RGA, Henle's gastrocolic trunk, RGEV, and accessory right colic vein, which were correctly identified during surgery. The branching pattern of the celiac trunk was classified as Michels type I in 19 patients and Michels type II in one patient. Imaging showed the RGA originating from the proper hepatic artery (PHA) in nine patients; from the gastroduodenal artery (GDA) in seven patients; and from the left hepatic artery (LHA) in four patients. In 12 patients, the LCV joined the portal vein (PV) and in eight, the splenic vein (SV). In all patients, the accessory right colic vein joined the RGEV, and Henle's gastrocolic trunk proximal to the joining point flowed to the superior mesenteric vein (SMV). In all 20 patients, the fused image simultaneously showed arteries and veins around the stomach, with no mismatch between the arterial and venous phase images. In 10 patients, the LCV joined the PV after running along the dorsal side of the PHA, common hepatic artery (CHA), or splenic artery (SA). In eight patients, the LCV joined the SV after running along the ventral side of the PHA, CHA, or SA. In two patients, the LCV joined the PV after running along the ventral side of the CHA, which correlated with the surgical findings. Both the sensitivity and positive predictive values of 3D CTA revealed 100% correct identification of the celiac trunk, LGA, RGA, LCV, Henle's gastrocolic trunk, RGEV, and accessory right colic vein. Dual-phase 3D CTA using 16-MDCT clearly revealed individual arteries and veins around the stomach before laparoscopic gastrectomy. The fused image of 3D CT arteriography and venography during a single breath-hold enabled the simultaneous assessment of arteries and veins before laparoscopic gastrectomy.

Relationship Between Various Patterns of Transient Increased Hepatic Attenuation on CT and Portal Vein Thrombosis Related to Acute Cholecystitis

We sought to investigate the prevalence of portal vein thrombosis in patients with acute cholecystitis and the relationship between portal vein thrombosis and the various patterns of transient increased hepatic attenuation on CT. We studied 72 of 107 patients with acute cholecystitis who, during a 3-year period, underwent dual-phase contrast-enhanced CT before percutaneous cholecystostomy or cholecystectomy. CT scans were retrospectively reviewed for the presence of portal vein thrombosis and location of the thrombi and for patterns of transient increased hepatic attenuation, which were classified as either pericholecystic, segmental, or mixed. Portal vein thrombi (two in hepatic segment IV, three in the left portal vein, and one in the right posterior portal vein) were found in six (8.3%) of 72 patients, and in those patients, transient increased attenuation with a segmental (five patients) or mixed (one patient) pattern was seen on CT. The pattern of transient increased attenuation in the 54 patients without portal vein thrombosis was pericholecystic in 41 (75.9%) and mixed in 13 (24.1%). Nineteen patients had segmental distribution (segmental or mixed pattern) that in 31.6% (6/19) of the patients was associated with portal vein thrombosis. Segmental distribution was more frequently found in those patients who had acute cholecystitis with portal vein thrombosis than in those who had only acute cholecystitis (p = 0.001). In patients with acute cholecystitis, portal vein thrombosis is not uncommon. Patterns of transient increased hepatic attenuation were found to vary, depending on the presence or absence of portal vein thrombosis.

CT and pathologic assessment of prospective nodal staging in patients with ductal adenocarcinoma of the head of the pancreas.

The aim of our study was to compare the assessment of peripancreatic lymph nodes using CT with the gold standard of detailed histopathologic assessment of resected specimens in patients with pancreatic ductal adenocarcinoma. Sixty-two patients with presumed pancreatic carcinoma were prospectively studied with dual-phase contrast-enhanced helical CT, and images were interpreted in consensus by three radiologists. Complete surgical resection was performed in 28 patients. A detailed nodal classification system was used for radiologic, surgical, and pathologic staging in the nine patients whose final diagnosis at histology was pancreatic ductal adenocarcinoma. Forty lymph nodes were prospectively identified on CT in these nine patients. Two of 23 nodes (9%) measuring less than 5 mm in the short-axis diameter were malignant, four of 11 nodes (36%) measuring 5-10 mm were malignant, and one of six nodes (17%) larger than 10 mm was malignant. Using a short-axis diameter of greater than 10 mm as the criterion for nodal involvement, we found a sensitivity of 14% (1/7) and a specificity of 85% (28/33), with a positive predictive value of 17% (1/6), a negative predictive value of 82% (28/34), and an overall accuracy of 73% (29/40). Ovoid nodal shape, clustering of nodes, and the absence of a fatty hilum were not useful predictors of malignancy on CT. In resectable pancreatic ductal adenocarcinoma, CT is not accurate overall for the prediction of nodal involvement. In a patient with presumed pancreatic carcinoma that is considered to be resectable, the depiction on CT of peripancreatic nodes should not prevent attempted curative resection.

Successful evaluation of pseudoaneurysm formation after blunt renal injury with dual-phase contrast-enhanced helical CT.

Successful evaluation of pseudoaneurysm formation after blunt renal injury with dual-phase contrast-enhanced helical CT.

Malignant focal hepatic lesions complicating underlying liver disease: dual-phase contrast-enhanced spiral CT sensitivity and specificity in orthotopic liver transplant patients.

The aim of this study was to determine the accuracy of contrast-enhanced biphasic spiral CT as a screening tool in the preoperative evaluation of orthotopic liver transplant (OLT) patients. Spiral-CT examinations were performed before liver transplantation in 53 patients. Scans were retrospectively reviewed and compared with pathologic findings in fresh-sectioned livers. When findings between spiral CT and pathology were discordant, formalized livers were reexamined with lesion-by lesion evaluation. Fresh pathologic evaluation revealed 23 liver lesions (16 HCC, 7 macro-regenerative nodules). Malignancy was identified in 13 of 53 patients (24.5%). Pre-transplantation spiral CT depicted 27 liver lesions (23 HCC, 4 macro-regenerative nodules). Malignancy was suspected in 14 patients (26.4%). In 10 of 53 (18.9%), spiral CT and pathologic evaluation were discordant. Subsequent retrospective pathologic evaluation showed malignancy in 4 additional patients. Spiral CT compared with the retrospective pathologic findings revealed 36 real-negative, 14 real-positive, 0 false-positive, and 3 false-negative patients with malignancy. Sensitivity and specificity of spiral CT in detection of malignancy was 82 and 100%, respectively. Contrast-enhanced biphasic spiral CT is an accurate technique in the evaluation of patients preceding OLT. Routine fresh-sectioned liver pathologic findings are not as sensitive as previously estimated.