Diagnostic performance of MRI and EUS in the differentiation of benign from malignant pancreatic cyst and cyst communication with the main duct

Purpose

To assess the diagnostic ability of MRI and EUS for differentiating benign from malignant pancreatic cyst focusing on cyst communication with pancreatic duct.

Materials and methods

During 44 months, we performed MRI on 65 pancreatic cysts. Among them, 36 patients had confirmed cyst communication with duct by ERCP or surgery and 39 patients underwent EUS. Fifty-one had proven by surgery or aspiration. Among them, 36 had confirmed malignant cysts. Two radiologists independently graded cyst communication with duct and the likelihood of malignancy. When the readers’ interpretations differed, third opinion was obtained. They also measured the size of cyst and main duct. The diagnostic performance was analyzed using the ROC curve. The Mann–Whitney U test and κ statistics were used to determine interobserver agreement.

Results

The Az of MRI and EUS for determining diagnostic performance regarding the cyst communication with duct, were 0.931 and 0.930, without statistically difference (p = 0.6). Interobserver agreement was excellent (κ = 0.81) on MRI and substantial (κ = 0.69) on EUS. The Az of MRI and EUS for assessing diagnostic performance to differentiate malignant from benign cyst, was 0.902 and 0.923, without statistically difference (p = 0.587). Interobserver agreement was excellent (κ = 0.81) on MRI and moderate (κ = 0.47) on EUS. The mean cyst size (3.98 cm + 2.74: 3.17 cm + 1.26, p = 0.327) and the duct size (5.20 mm + 3.22: 4.39 mm + 4.12, p = 0.227) showed no statistically difference between malignant and benign cysts.

Conclusion

MRI and EUS can accurately assess pancreatic cyst communication with duct and are very useful for obtaining a differential diagnosis of malignant cyst versus benign pancreatic cyst.     

Comparison of axial, coronal, and primary 3D review in MDCT colonography for the detection of small polyps: a phantom study

Purpose

The purpose of this phantom study is to compare the influence of the reading technique (axial images alone in comparison to 3D endoluminal, coronal, and combined 2D/3D review methods) on the sensitivity and inter-reader variability with MDCT colonography for the detection of small colonic polyps.

Methods

An anthropomorphic pig colon phantom with 75 randomly distributed simulated small polyps of 2–8 mm size, was distended with air and scanned in a water phantom using multidetector-row CT with 4 mm × 1 mm collimation. Three radiologists rated the presence of polyps on a five-point scale. Performance with axial sections alone was compared to the performance with coronal sections, virtual endoscopy (VE), and a combined 2D/3D approach. We calculated sensitivities for polyp detection and used ROC analysis for data evaluation.

Results

There was no significant difference between the mean area under the curve (A_z) for axial images and VE (A_z = 0.934 versus 0.932), whereas coronal images were significantly inferior (A_z = 0.876) to both. The combined 2D/3D approach yielded the best results, with an A_z of 0.99. Differences in sensitivity between individual readers were significant in axial images (sensitivity, 75–93%, p = 0.001) and coronal images (sensitivity, 69–80%, p = 0.028), but became non-significant with VE (83–88%, p = 0.144) and the combined 2D/3D approach (95–97%, p = 0.288).

Conclusion

Evaluation of axial sections alone leads to significant differences in detection rates between individual observers. A combined 2D/3D evaluation improves sensitivities for polyp detection and reduces inter-individual differences to an insignificant level.     

Lymphomas and glioblastomas: differences in the apparent diffusion coefficient evaluated with high b-value diffusion-weighted magnetic resonance imaging at 3T

Background and purpose

As the usefulness of the apparent diffusion coefficient (ADC) obtained from diffusion-weighted images (DWI) for the differential diagnosis between glioblastoma and primary central nervous system lymphoma is controversial, we assessed whether high b-value DWI at b 4000 s/mm² could discriminate between glioblastoma and lymphoma. We also compared the power of high- and standard b-value (b-4000, b-1000) imaging on a 3-Tesla (3 T) magnetic resonance (MR) instrument.

Materials and methods

This study was approved by our Institutional Review Board. We acquired DWI at 3 T with b = 1000 and b = 4000 s/mm² in 10 patients with lymphoma and 14 patients with glioblastoma. The ADC was measured by placing multiple regions of interest (ROI) on ADC maps of the site of enhanced lesions on contrast-enhanced T1-weighted MR images. We avoided hemorrhagic and cystic lesions by using T1-, T2-, FLAIR-, and T2* MR images. The ADC values of each tumor were determined preoperatively from several ROI and expressed as the minimum-, mean-, and maximum ADC value (ADC_MIN, ADC_MEAN, ADC_MAX). We evaluated the relationship between ADCs and histological information including tumor cellularity.

Results

All ADC values were statistically associated with tumor cellularity. ADC_MIN at b-4000 was associated with tumor cellularity more significantly than ADC_MIN at b-1000. All ADC values were lower for lymphoma than glioblastoma and the statistical difference was larger at b = 4000- than b = 1000 s/mm². According to the results of discriminant analysis, the log likelihood was greatest for ADC_MIN at b = 4000. At a cut-off value of ADC_MIN = 0.500 × 10⁻³ mm²/s at b-4000 it was possible to differentiate between lymphoma and glioblastoma (sensitivity 90.9%, specificity 91.7%).

Conclusions

Calculating the ADC value is useful for distinguishing lymphoma from glioblastoma. The lowest degree of overlapping and a better inverse correspondence with tumor cellularity were obtained with ADC_MIN at b-4000 s/mm² at 3 T MRI.     

Assessment of colorectal hepatic metastases by quantitative T2 relaxation time

Aim

To determine the T₂ relaxation time of colorectal hepatic metastases and changes in T₂ relaxation times following chemotherapy.

Materials and methods

42 patients with 96 hepatic colorectal metastases underwent baseline MRI. Axial T₁, T₂ and multi-echo GRASE sequences were acquired. ROIs were drawn on T₂ relaxation maps, obtained from GRASE images, encompassing metastasis and normal liver to record T₂ relaxation time values. In 11 patients with 28 metastases, MRI was repeated using same protocol at 6 weeks following chemotherapy. The median pre-treatment T₂ values of metastases and normal liver were compared using the Mann–Whitney test. The pre- and post-treatment median T₂ values of metastases were compared using the Wilcoxon–Rank test for responding (n = 16) and non-responding (n = 12) lesions defined by RECIST criteria. The change in T₂ values (ΔT₂) were compared and correlated with percentage change in lesion size.

Results

There was no difference in the pre-treatment median T₂ of metastases between responding (67.3 ± 8.6) and non-responding metastases (71.4 ± 16.5). At the end of chemotherapy, there was a decrease in the median T₂ of responding lesions (61.6 ± 12.6) p = 0.83, and increase in non-responding lesions (76.2 ± 18.4) p = 0.03, but these were not significantly different from the pre-treatment values. There was no significant difference in ΔT₂ of responding and non-responding lesions (p = 0.18) and no correlation was seen between size change and ΔT₂ (coefficient = 0.3).

Conclusion

T₂ relaxation time does not appear to predict response of colorectal liver metastasis to chemotherapy.     

Biliary anatomy in potential right hepatic lobe living donor liver transplantation (LDLT): the utility of CT cholangiography in the setting of inconclusive MRCP

Objective

To determine the utility of CT cholangiography (CT-Ch) in preoperative evaluation of the biliary anatomy of living-donor liver transplantation (LDLT) donors when magnetic resonance cholangiopancreatography (MRCP) is inconclusive.

Materials and methods

Over a 2-year period, 22 potential living liver donors underwent contrast-enhanced CT-Ch for preoperative evaluating biliary anatomy due to inconclusive results on MRCP and subsequently donated their right hepatic lobe. Nineteen of them underwent intraoperative cholangiography and were included in this study. Two radiologists retrospectively reviewed both MRCP and CT-Ch with 1-month interval and documented the types of bile duct branching patterns and visualization score of intrahepatic bile ducts (4-point scale).

Results

There were no complications associated with CT-Ch examinations. CT-Ch was concordant with the reference standard in 18/19 (95%) including 7/8 typical branching type and 11/11 anomalous branching types. MRCP was concordant with the reference standard in 14/19 (74%) including 4/8 typical branching types and 10/11 anomalous branching types. The discordant case by CT-Ch was the identification of a tiny accessory right intrahepatic duct joining the common bile duct which was not visualized on intraoperative cholangiography. CT-Ch showed higher visualization score (mean, 3.9) than MRCP (mean, 2.6) (P < .001).

Conclusion

CT-Ch can be effectively used for the depiction of the branching pattern of the bile duct at the hepatic hilum when MRCP is inconclusive.     

Intraductal papillary mucinous neoplasm of the pancreas: differentiate from chronic pancreatits by MR imaging

Purpose

To evaluate the differentiating factors for intraductal papillary mucinous neoplasm of the pancreas and chronic pancreatitis as determined by MR imaging.

Materials and methods

During a three-year period, we performed MR imaging on 33, consecutive patients with IPMN and on 41 patients with chronic pancreatitis. All IPMNs were confirmed by surgery. Two radiologists retrospectively analyzed the ductal change, the cyst shape, CBD dilatation, lymphadenopathy, and parenchymal change. The sensitivity and specificity were calculated for each MRI findings using the Chi square test. Statistically significant MR findings were further analyzed using multivariate logistic regression analysis. The diagnostic performance was evaluated according to the area under the receiver operating characteristic curve (A_z) using specific MRI findings. Simple κ statistics were used to evaluate the inter-observer reliability.

Results

Statistically specific findings for IPMN compared with those for chronic pancreatitis, were duct dilatation without stricture (specificity = 95.1%, sensitivity = 75.8%, p < 0.0001), bulging ampulla (specificity = 97.6%, sensitivity = 30.3%, p < 0.0001), nodule in a duct (specificity = 100%, sensitivity = 15.2%, p < 0.0004), grape-like cyst shape (specificity = 97.6%, sensitivity = 78.8%, p < 0.0001), and nodule in a cyst (specificity = 100%, sensitivity = 24.2%, p < 0.0001). Statistically specific findings for chronic pancreatitis compared with those for IPMN, were duct dilatation with strictures (specificity = 93.9%, sensitivity = 95.1%, p < 0.0001), the presence of a stone (specificity = 97.0%, sensitivity = 56.1%, p < 0.0001), and a unilocular cyst shape (specificity = 93.9%, sensitivity = 34.1%, p < 0.0004). Duct dilatation without stricture and a grape-like cyst shape were independently associated with the IPMN. Duct dilatation with strictures was independently associated with the chronic pancreatitis. Interobserver agreement was good to excellent for each finding (κ = 0.762–1.000).

Conclusion

Highly specific findings for IPMN include duct dilatation without stricture, bulging ampulla, nodule in a duct, grape-like cyst shape, and nodule in a cyst. MRI is very useful for differentiating IPMN from chronic pancreatitis using these specific findings.     

MR-imaging of the thoracic aorta: 3D-ECG- and respiratory-gated bSSFP imaging using the CLAWS algorithm versus contrast-enhanced 3D-MRA

Objective

To compare a contrast-enhanced 3D angiography (CE-3D-MRA) with the ECG- and respiratory gated 3D balanced steady state free precession (bSSFP) sequence using the CLAWS algorithm (3D-bSSFP-CLAWS) with respect to acquisition time, image quality, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR).

Methods

14 patients (4 women, mean age ± SD: 52 ± 18) with known or suspected thoracic aortic disease were imaged on a 1.5 T scanner with both sequences. Two readers scored image quality of predefined levels of the thoracic aorta. Acquisition time, SNR and CNR were calculated for each examination.

Results

Image quality achieved with the 3D-bSSFP-CLAWS was scored significantly better than with the CE-3D-MRA for the aortic annulus (P = 0.003), the sinuses of Valsalva (P = 0.001), the proximal coronary arteries (P = 0.001) and the sinotubular junction (P = 0.001). Effective acquisition time for the 3D-bSSFP-CLAWS and corrected acquisition time (corrected for imaging parameters) was significantly longer compared to the CE-3D-MRA (P = 0.004 and P = 0.028). SNR and CNR were significantly higher for the CE-3D-MRA (P = 0.007 and P = 0.001).

Conclusions

Providing the highest scan efficiency for a given breathing pattern, image quality for the proximal ascending aorta achieved with the 3D-bSSFP-CLAWS is significantly superior in contrast to the CE-3D-MRA.     

Crohn's disease: CT enterography manifestations before and after treatment

Purpose

The purpose of this study was to determine whether CT enterography (CTE) changes of Crohn's disease (CD) after treatment correlated with clinical remission.

Materials and methods

We retrospectively studied 50 known CD patients (male: 35; female: 15) with clinical remission in a period of 3 years (2005–2008). CD was diagnosed by clinical, enteroscopic and pathologic manifestations. Clinical remission was identified by experienced gastroenterologists using the combing criteria of clinical, endoscopy and laboratory tests. First CTE and endoscopy exams were performed during their first hospitalization in our hospital meanwhile CD diagnosis was made during that time. Repeated CTE and endoscopy exams were done after treatment. CTE findings were determined by two experienced radiologists with double-blind approach. Each patient was analyzed for the CTE parameters including bowel wall attenuation, bowel wall thickening (>3 mm), bowel wall thickening types (type A: multilayered mural stratification; type B: two layers with strong mucosal enhancement and prominent low-density submucosa; type C: two layers without strong mucosal enhancement; type D: homogeneous enhancement) comb sign, luminal stenosis (mild: luminal diameter 2–3 cm; moderate: luminal diameter 1–2 cm; severe: luminal diameter < 1 cm) and the presence of extraenteric complications (such as fistulas and abscess). All the quantitative parameters were measured three times by each review.

Results

After treatment, bowel wall thickening was attenuated in 88% of CD patients. Thickness of bowel wall was decreased from 8.8 ± 2.8 mm to 6.4 ± 1.9 mm (P < 0.001). CT value of bowel wall in portal stage was also declined from 90.0 ± 15.4 (HU) to73.4 ± 14.2 (HU (P < 0.001). The percentage of patients with type A or B bowel wall thickening was decreased from 78.7% to 35.4%, while those with type C or D thickening was increased from 21.2% to 64.6% (P < 0.001). The percentage of patients with comb sign was decreased from 88% to 60% (P = 0.001). The percentage of patients with moderate or severe luminal stenosis was reduced from 74% to 32% (P < 0.001). The ROC (receiver operating characteristic) analysis showed bowel wall attenuation (A_z = 0.89) and bowel wall thickness (A_z = 0.81) were the two best parameters to predict disease activity, and combining of these two values was better than using them solely (κ = 0.71, P < 0.001). The bowel wall attenuation (OR = 9.56, P < 0.001) and bowel wall thickness (OR = 3.32, P = 0.001) were significantly correlated with the disease activity in the following logistic regression analysis.

Conclusion

Therapeutic effect of CD and disease activity can be properly evaluated by CTE.     

Autoimmune pancreatitis: Assessment of the enhanced duct sign on multiphase contrast-enhanced computed tomography

Purpose

To assess the usefulness of the computed tomography (CT) finding of main pancreatic duct (MPD) wall enhancement, termed the “enhanced duct sign”, for diagnosis of autoimmune pancreatitis (AIP) in comparison with diagnosis of pancreatic carcinoma and chronic pancreatitis.

Materials and methods

Two radiologists independently evaluated the presence or absence of the enhanced duct sign on multiphase contrast-enhanced CT in patients with AIP (n = 55), pancreatic carcinoma (n = 50), and chronic pancreatitis (n = 50). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of AIP were calculated. In patients demonstrating the enhanced duct sign, additional findings were evaluated by consensus.

Results

The enhanced duct sign was more frequently observed in patients with AIP (37/55, 67%) than in patients with pancreatic carcinoma (5/50, 10%) or chronic pancreatitis (0/50, 0%) (P < 0.05). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the finding were 0.67, 0.95, 0.85, 0.88, and 0.84, respectively. In AIP, the lumen within the enhanced duct was completely or partially invisible in 29 of 37 (78%) patients, and the enhanced duct was observed within the affected pancreatic parenchyma in 35 of 37 (95%) patients. In pancreatic carcinoma, the lumen within the enhanced duct was visible in all patients (5/5, 100%), and the enhanced duct was observed downstream of the tumor (5/5, 100%).

Conclusion

The enhanced duct sign is highly specific of AIP.     

T1ρ and T2 mapping of the proximal tibiofibular joint in relation to aging and cartilage degeneration

Objective

To study the effects of aging and cartilage degeneration of the proximal tibiofibular- and femorotibial joint (PTFJ, FTJ) on the cartilage of the PTFJ using T₁ρ and T₂ mapping.

Materials and methods

We performed sagittal T₁ρ and T₂ mapping of the PTFJ and FTJ on 55 subjects with knee disorders. We placed 3 regions of interest (ROIs) on images of the cartilage in the PTFJ, medial femoral condyle (MFC), and medial tibia plateau (MTP). Correlation analysis was performed for the T₁ρ and T₂ values of each ROI and the patient age and the osteoarthritic grade of the PTFJ and FTJ.

Results

The T₁ρ and T₂ values of the PTFJ were affected neither by aging nor the osteoarthritic grade of the FTJ. Values of the FTJ normalized to PTFJ values were correlated with the osteoarthritic grade of the FTJ in the MFC (r = 0.851 and 0.779, respectively) and the MTP (r = 0.635 and 0.762, respectively). There was a significant difference in the T₁ρ but not the T₂ value of the PTFJ and MFC between normal and mildly osteoarthritic cartilage of each joint.

Conclusion

We document that the T₁ρ and T₂ values of PTFJ cartilage were not affected by aging or cartilage degeneration in the FTJ. The T₁ρ value of the PTFJ may represent a useful internal standard reference for evaluating early degeneration of the FTJ.     

Unilateral lower lung field opacities on chest radiography: a comparison of the clinical manifestations of tuberculosis and pneumonia

Background

The radiological manifestations of lower lung field (LLF) tuberculosis (LLFTB) are similar to those of LLF pneumonia (LLFP), making diagnosis challenging. The aim of this study was to determine if there are differences in the clinical manifestations of LLFTB and LLFP in patients with unilateral LLF opacities.

Methods

We performed a retrospective review of patient records to identify those with unilateral LLF opacities who were subsequently diagnosed with LLFTB or LLFP. We compared demographics, clinical manifestations, hematological data, and radiographic findings between the groups of patients.

Results

We identified 22 and 72 patients diagnosed with LLFTB and LLFP, respectively. Multivariate analysis revealed that age (odds ratio [OR] = 1.05, 95% confidence interval [CI] = 0.99–1.11, P = 0.072), lack of fever > 38 °C (OR = 9.04, 95% CI = 1.69–48.40, P = 0.001), duration of symptoms ≥ 7 days (OR = 4.57, 95% CI = 1.09–19.26, P = 0.038), and the lack of air bronchograms upon radiography (OR = 12.08, 95% CI = 1.98–73.64, P = 0.007) were significant predictors of LLFTB in patients with LLF opacities. We used these predictors to construct a mathematical model for predicting LLFTB in patients with LLF opacities.

Conclusions

Our findings suggest that older age, prolonged duration of symptoms, lack of fever > 38°C, and the absence of air bronchograms are more common in patients with LLFTB than patients with LLFP. These findings may help clinicians differentiate between LLFTB and LLFP and thus initiate timely and appropriate treatment.     

4D phase contrast flow imaging for in-stent flow visualization and assessment of stent patency in peripheral vascular stents - A phantom study

Purpose

4D phase contrast flow imaging is increasingly used to study the hemodynamics in various vascular territories and pathologies. The aim of this study was to assess the feasibility and validity of MRI based 4D phase contrast flow imaging for the evaluation of in-stent blood flow in 17 commonly used peripheral stents.

Materials and methods

17 different peripheral stents were implanted into a MR compatible flow phantom. In-stent visibility, maximal velocity and flow visualization were assessed and estimates of in-stent patency obtained from 4D phase contrast flow data sets were compared to a conventional 3D contrast-enhanced magnetic resonance angiography (CE-MRA) as well as 2D PC flow measurements.

Results

In all but 3 of the tested stents time-resolved 3D particle traces could be visualized inside the stent lumen. Quality of 4D flow visualization and CE-MRA images depended on stent type and stent orientation relative to the magnetic field. Compared to the visible lumen area determined by 3D CE-MRA, estimates of lumen patency derived from 4D flow measurements were significantly higher and less dependent on stent type. A higher number of stents could be assessed for in-stent patency by 4D phase contrast flow imaging (n = 14) than by 2D phase contrast flow imaging (n = 10).

Conclusions

4D phase contrast flow imaging in peripheral vascular stents is feasible and appears advantageous over conventional 3D contrast-enhanced MR angiography and 2D phase contrast flow imaging. It allows for in-stent flow visualization and flow quantification with varying quality depending on stent type.     

Impact of butylscopolamine on image quality of magnetic resonance cholangiopancreatography

Purpose

To assess the effect of parenteral butylscopolamine on magnetic resonance cholangiopancreatography (MRCP) image quality.

Materials and methods

The 3D free-breathing respiratory-compensated MRCP images (mean acquisition time 7 min) of 94 consecutive non-paired patients (47 with and 47 without 20 mg intramuscular butylscopolamine) were analysed retrospectively. Two experienced abdominal radiologists scored the image quality of five predefined pancreaticobiliary ductal segments on the MRCP images in a blinded fashion in both cohorts using a 5 point validated scale, ranging from perfect visualization of the entire ductal structure to the ductal structure being not visible. Interobserver agreement was determined.

Results

Parenteral butylscopolamine injection significantly reduced bowel peristalsis-related artefacts of the inferior common bile duct (CBD; p = 0.031) and the pancreatic duct (PD; p = 0.034) for reader 1 and the inferior CBD (p = 0.041) for reader 2. The difference in visualization of all remaining ductal segments, and of the overall pancreaticobiliary tree, was not statistically significant between the two cohorts. Interobserver agreement between the two readers was substantial for the superior CBD, common hepatic duct (CHD) and PD, was moderate for the inferior CBD, and was fair for the peripheral intrahepatic ducts.

Conclusion

On free-breathing 3D MRCP images, parenteral butylscopolamine improves only the visualization of the inferior CBD and the PD. However, no significant improvement in visualization of other ductal segments was demonstrated.     

Assessment of acute cholangitis by MR imaging

Purpose

The purpose of this study is to assess the common MRI findings of acute cholangitis compared with those of non-acute cholangitis.

Materials and methods

During a 31-month period, we performed MRCP and contrast-enhanced MRI on 173 patients with biliary abnormalities including duct dilatation or stricture. The causes of the biliary abnormalities included biliary stone disease (n = 85), cholangiocarcinoma (n = 47), periampullary cancer (n = 20), GB cancer (n = 4), and others (n = 17). Among 173 patients, 66 consecutive patients were confirmed with acute cholangitis diagnosed according to the Tokyo guideline, and 107 patients were confirmed as having non-acute cholangitis. Two radiologists retrospectively and independently accessed the MR findings, including the cause of biliary abnormality, increased periductal signal intensity on T2-weighted images, the transient periductal signal difference, and the presence of abscess, thrombosis, and ragged duct. They also measured the dilated duct and the thickened wall. The Student t-test and the Pearson chi-square were used. The κ statistics were used to determine interobserver agreement. Logistic regression was used to identify the MR findings that predicted acute cholangitis.

Results

MRI correctly accessed the cause of biliary abnormality in 163 patients (94%). The statistically common findings for acute cholangitis were as follows: increased periductal signal intensity on T2-weighted imaging (n = 26, 39%, p < 0.05); transient periductal signal difference (n = 31, 47%, p < 0.05); abscess (n = 18, 27%, p < 0.05); thrombosis (n = 12, 18%, p < 0.05); and ragged duct (n = 11, 17%, p < 0.05). Interobserver agreement was good to excellent for each finding (κ = 0.74–0.97). The wall thickness showed a statistically significant difference between the acute cholangitis and the non-acute cholangitis group (2.65 mm:2.32 mm, p < 0.05), however, there was no significant difference in duct dilatation in the two groups. The periductal transient attenuation difference was an independent predictor of acute cholangitis (Exp (B) = 6.389, p = 0.018).

Conclusion

MRI accurately assesses the cause of biliary abnormality in patients with cholangitis. Using statistically common MR findings for acute cholangitis, MR imaging is very successful in predicting acute cholangitis.     

Radiological abnormalities associated with Aspergillus colonization in a cystic fibrosis population

Objective

To determine if sputum colonization with Aspergillus species in patients with cystic fibrosis (PWCF) correlates with radiological abnormalities and/or a reduction in pulmonary function (FEV1).

Methods

We prospectively evaluated 32 PWCF utilizing high resolution computed tomography (HRCT) of the thorax and pulmonary function testing (PFT). The cohort was assessed as two groups: Aspergillus positive (n = 16) and Aspergillus negative (n = 16) based on sputum culture for Aspergillus species. A modified Bhalla scoring system was applied to each HRCT scan by two blinded radiologists.

Results

Aspergillus positive patients had more severe and significant bronchiectasis compared to those Aspergillus negative (p < 0.05). This was most marked in the right upper and lower lobes (RUL, RLL). Total Bhalla score was clinically significant in both groups and approached statistical significance between groups (p = 0.063). No difference in pulmonary function between the groups was detected.

Conclusion

PWCF colonized by Aspergillus species have greater radiological abnormalities undetectable by PFTs. Early radiological evaluation of Aspergillus colonized PWCF is therefore warranted.     

The role of ultrasound and magnetic resonance cholangiopancreatography for the diagnosis of biliary stricture after liver transplantation

Purpose

To identify the diagnostic value of ultrasound (US) and magnetic resonance cholangiopancreatography (MRCP) in diagnosing biliary strictures after liver transplantation.

Materials and methods

Sixty patients with clinically suspected biliary strictures after liver transplantation were retrospectively evaluated. All patients underwent US and MRCP before the standard of reference (SOR) procedure: endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangiography. Radiological images were analyzed for biliary dilatation and strictures.

Results

By SOR, biliary dilatation was present in 55 patients, stricture in 53 (44 anastomotic, 4 intrahepatic, 5 both), and dilatation and/or stricture in 58. Dilatation was diagnosed by US and MRCP in 39 and 45, respectively (sensitivity 71% vs. 82%, p = 0.18). Stricture was diagnosed by US and MRCP in 0 and 42, respectively (sensitivity 0% vs. 79%, p < 0.0001). False positive stricture was diagnosed by MRCP in 2. Dilatation and/or stricture was diagnosed by US in 39 and MRCP in 50 (sensitivity 67% vs. 86%, p = 0.01); however, using both techniques, sensitivity increased to 95%.

Conclusions

MRCP is superior to US for diagnosing biliary strictures after liver transplantation primarily because MRCP can detect stricture. The combination of US and MRCP seems superior to either method alone. Our data suggest that in patients with normal US and MRCP, direct cholangiography could be avoided.     

Comparison of 3D two-point Dixon and standard 2D dual-echo breath-hold sequences for detection and quantification of fat content in renal angiomyolipoma

Purpose

To assess the utility of a 3D two-point Dixon sequence with water–fat decomposition for quantification of fat content of renal angiomyolipoma (AML).

Methods

84 patients underwent renal MRI including 2D in-and-opposed-phase (IP and OP) sequence and 3D two-point Dixon sequence that generates four image sets [IP, OP, water-only (WO), and fat-only (FO)] within one breath-hold. Two radiologists reviewed 2D and 3D images during separate sessions to identify fat-containing renal masses measuring at least 1 cm. For identified lesions subsequently confirmed to represent AML, ROIs were placed at matching locations on 2D and 3D images and used to calculate 2D and 3D SI_index [(SI_IP − SI_OP)/SI_IP] and 3D fat fraction (FF) [SI_FO/(SI_FO + SI_WO)]. 2D and 3D SI_index were compared with 3D FF using Pearson correlation coefficients.

Results

41 AMLs were identified in 6 patients. While all were identified using the 3D sequence, 39 were identified using the 2D sequence, with the remaining 2 AMLs retrospectively visible on 2D images but measuring under 1 cm. Among 32 AMLs with a 3D FF of over 50%, both 2D and 3D SI_index showed a statistically significant inverse correlation with 3D FF (2D SI_index: r = −0.63, p = 0.0010; 3D SI_index: r = −0.97, p < 0.0001).

Conclusion

3D two-point Dixon sequence may provide a reasonable alternative to 2D dual-echo sequence for detection of renal AML and may have additional value for quantification of fat content of these lesions given the observation that 3D FF, unlike 2D and 3D SI_index, is not limited by ambiguity of water or fat dominance. This may assist clinical management of AML given evidence that fat content predicts embolization response.     

Diagnosis of liver metastases: Can diffusion-weighted imaging (DWI) be used as a stand alone sequence?

Objectives

To evaluate if diffusion-weighted MRI (DWI) can replace gadolinium-enhanced MRI (Gd-MRI) for diagnosing liver metastases. The diagnostic accuracy of both techniques alone and in combination are compared.

Materials and methods

Sixty-eight patients with histologically proven primary extrahepatic tumors were included in this retrospective study. Lesions included 62 metastases and 130 benign lesions. Three image sets (unenhanced T1 and T2/gadolinium enhanced T1 (Gd-MRI), DWI and combination of both) were reviewed independently by 3 observers. The areas under the receiver operating characteristic curves (A_z), sensitivity and specificity for the 3 image sets were compared. The standard of reference was either histopathology or multi-modality and clinical follow-up.

Results

Pooled data showed higher diagnostic accuracy for the combined set (A_z = 0.93) compared to Gd-MRI (p = 0.001) and DWI (p < 0.0001). No difference was found between the performance of Gd-MRI and DWI (p = 0.09). Sensitivity for the combined set was higher than Gd-MRI (p = 0.0003) and DWI (p = 0.0034). Specificity for DWI was lower than Gd-MRI (p < 0.0001) and the combined set (p < 0.0001).

Conclusion

The diagnostic performance of DWI is equal to that of Gd-MRI. DWI alone can be used in patients where gadolinium contrast administration is not allowed. Combination of Gd-MRI and DWI significantly increases diagnostic accuracy.     

Could ultrasonic elastography help the diagnosis of small (≤2 cm) breast cancer with the usage of sonographic BI-RADS classification?

Objectives

To evaluate the additive value of ultrasound strain elastography (USE) to BI-RADS for the differentiation of benign and malignant breast small lesions.

Methods

Breast masses (≤2 cm) with histological diagnosis examined by ultrasonography and USE in our department from April 2004 to December 2009 were reviewed. Conventional B-mode ultrasound findings were classified according to the BI-RADS classification. USE findings were classified according to the 5-point scale. Histological diagnosis was used as the reference standard.

Results

401 (246 benign (61.3%), 155 malignant (38.7%)) from 370 consecutive patients were included in the study. Sensitivity and specificity were 90.3%, 68.3% for BI-RADS; 72.3%, 91.9% for USE. The sensitivity of BI-RADS was better than that of USE (P < 0.05), while the specificity of USE was better than that of BI-RADS (P < 0.05). A revised BI-RADS combined with USE results was proposed in this study. Sensitivity and specificity were 83.9% and 87.8% for revised BI-RADS. The diagnostic performance of revised BI-RADS was better than BI-RADS (P < 0.05).

Conclusions

USE could give BI-RADS some help in the differentiation of benign and malignant breast small lesions. The addition of elastography to BI-RADS could improve the diagnostic performance in <2 cm lesions.     

Intermodality comparison between 3D perfusion CT and 18F-FDG PET/CT imaging for predicting early tumor response in patients with liver metastasis after chemotherapy: Preliminary results of a prospective study

Objectives

To evaluate the feasibility of 3D perfusion CT for predicting early treatment response in patients with liver metastasis from colorectal cancer.

Methods

Seventeen patients with colon cancer and liver metastasis were prospectively enroled to undergo perfusion CT and 18F-FDG-PET/CT before and after one-cycle of chemotherapy. Two radiologists and three nuclear medicine physicians measured various perfusion CT and PET/CT parameters, respectively from the largest hepatic metastasis. Baseline values and reduction rates of the parameters were compared between responders and nonresponders. Spearman correlation test was used to correlate perfusion CT and PET/CT parameters, using RECIST criteria as reference standard.

Results

Nine patients responded to treatment, eight patients were nonresponders. Baseline SUV_mean30 on PET/CT, reduction rates of 30% metabolic volume and 30% lesion glycolysis (LG₃₀) on PET/CT and blood flow (BF) and flow extraction product (FEP) on perfusion CT after chemotherapy were significantly different between responders and nonresponders (P = 0.008–0.046). Reduction rates of BF (correlation coefficient = 0.630) and FEP (correlation coefficient = 0.578) significantly correlated with that of LG₃₀ on PET/CT (P < 0.05).

Conclusion

CT perfusion parameters including BF and FEP may be used as early predictors of tumor response in patients with liver metastasis from colorectal cancer.