Acta Radiologica

The performance of diffusion-weighted imaging parameters for characterizing hepatic tumors is controversial.

To compare the performances of apparent diffusion coefficient (ADC) and intravoxel incoherent motion (IVIM)-derived parameters, including the pure diffusion coefficient (D), perfusion coefficient (D*), and perfusion fraction (f), in the characterization of common solid hepatic tumors.

Twelve healthy volunteers and 43 patients underwent free-breath diffusion-weighted magnetic resonance imaging (DW-MRI) of the liver using eight b values (10–800 s/mm²). Twelve regions of interest (ROIs) of normal liver tissue in healthy volunteers and 49 hepatic lesions (23 hepatocellular carcinomas [HCCs], 16 hemangiomas, and 10 metastases) were measured. Conventional ADC_(0,500) and ADC_total obtained by the mono-exponential model, as well as D, D*, and f were calculated. Student t-tests and receiver operating characteristic (ROC) analysis were also performed.

ADC_(0,500), ADC_total, and D were significantly lower in the malignant group ([1.48 ± 0.35] × 10⁻³ mm²/s; [1.35 ± 0.30] × 10⁻³ mm²/s; [1.18 ± 0.33] × 10⁻³ mm²/s) compared to the hemangioma group ([2.74 ± 1.03] × 10⁻³ mm²/s; [2.61 ± 0.81] × 10⁻³ mm²/s; [1.97 ± 0.79] × 10⁻³ mm²/s]. D* did not differ among multiple comparisons. For the area under the ROC curve (AUC-ROC), the maximum value was attained with ADC_total (0.983) and was closely followed by ADC_(0,500) (0.967), with lower values obtained for D (0.837), f (0.649), and D* (0.599). Statistically significant differences were found between the AUC-ROC of both ADCs (ADC_total and ADC_(0,500)) and D. There was no statistically significant difference between the AUC-ROC of ADC_total and ADC_(0,500).

ADCs showed superior diagnostic performance compared to IVIM-derived parameters in detecting differences between the malignant group and hemangioma group.

Despite novel software solutions, liver volume segmentation is still a time-consuming procedure and often requires further manual optimization. With the high signal intensity of the liver parenchyma in Gd-EOB enhanced magnetic resonance imaging (MRI), liver volume segmentation may be improved.

To evaluate the practicability of threshold-based segmentation of the liver volume using Gd-EOB-enhanced MRI including a customized three-dimensional (3D) sequence.

A total of 20 patients examined with Gd-EOB MRI (hepatobiliary phase T1-weighted (T1W) 3D sequence [VIBE]; flip angle [FA], 10° and 30°) were enrolled in this retrospective study. The datasets were independently processed by two blinded observers (O1 and O2) in two ways: manual (man) and threshold-based (thresh; study method) segmentation of the liver each followed by an optimization step (man+opt and thresh+opt; man+opt [FA10°] served as reference method). Resulting liver volumes and segmentation times were compared. A liver conversion factor was calculated in percent, describing the non-hepatocellular fraction of the total liver volume, i.e. bile ducts and vessels.

Thresh+opt (FA10°) was significantly faster compared to the reference method leading to a median volume overestimation of 4%/8% (P < 0.001). Using thresh+opt (FA30°), segmentation was even faster (P < 0.001) and even reduced median volume deviation of 0%/2% (O1/O2; both P > 0.2). The liver conversion factor was found to be 10%.

Threshold-based liver segmentation employing Gd-EOB-enhanced hepatobiliary phase standard T1W 3D sequence is accurate and time-saving. The performance of this approach can be further improved by increasing the FA.

There has been a growing need for an imaging method for the accurate diagnosis and staging of liver fibrosis as a non-invasive alternative to liver biopsy.

To evaluate the feasibility of intra-voxel incoherent motion (IVIM) imaging for classifying the severity of liver fibrosis.

Fifty-seven patients who underwent navigator-triggered, diffusion-weighted imaging (DWI) of the liver on a 1.5-T system using nine b-values and had a reliable reference standard for the diagnosis of liver fibrosis (histopathologic findings [n = 27] or clinical findings for normal [n = 18] or cirrhotic liver [n = 12]), were included in our study. Liver apparent diffusion coefficient (ADC), pure diffusion (D_slow), perfusion fraction (f), and perfusion-related diffusion (D_fast), and the product f · D_fast were compared with the liver fibrosis stages (F). The accuracies of these parameters in diagnosing severe liver fibrosis (F ≥3) were evaluated using the receiver-operating characteristic (ROC) curve analysis.

The liver fibrosis stages had the strongest negative correlation with f · D_fast (ρ = –0.52). All of the parameters, except for D_slow, were significantly lower in patients with F ≥3 than in those with F ≤2 (P ≤ 0.001). The area under the ROC curve for diagnosing severe fibrosis was the largest for f · D_fast (0.844) with an overall accuracy of 79.0% (45/57) at the optimal cutoff value and followed by f (0.834), D_fast (0.773), ADC (0.762), and D_slow (0.656).

IVIM imaging is a promising method for classifying the severity of liver fibrosis, with the product f · D_fast being the most accurate parameter.

Given that transarterial chemoembolization (TACE) is usually a repeated procedure for treatment of hepatocellular carcinoma (HCC), repeated radiologic response assessments rather than a single time point assessment may have different clinical implications through the repeated course of TACE.

To evaluate the efficacy of RECIST and mRECIST criteria as a survival predictor across early time points after repeated TACE of HCC.

Ninety-eight patients with intermediate stage HCC received repeated iodized oil TACE. Treatment response was assessed according to RECIST and mRECIST criteria at 1, 3, and 6 months after initial TACE. Cox proportional model was used for survival analysis and the predicting power of each time point response was evaluated with C-statistics and time-dependent area under the receiver operating characteristic curve (AUC). Inter-method agreement was assessed with the κ coefficient.

mRECIST was not applicable in 15 patients because of patchy uptake of iodized oil after TACE. On multivariate analysis, responders at 6 months by RECIST, responders at 3 months, and 6 months by mRECIST showed better survival than non-responders (P < 0.05). Predicting power of response criteria improved over time and mRECIST at 6 months showed the best performance. The degree of agreements was poor or fair between RECIST and mRECIST.

mRECIST predicted long-term survival as early as 3 months after TACE of intermediate stage HCC. The predicting power of the uni-dimensional response criteria tended to be stronger over time.

Because further treatment plans depends on lymph node (LN) status after neoadjuvant chemoradiation therapy (CRT), the accurate characterization of LN is important.

To evaluate the diagnostic performance of apparent diffusion coefficient (ADC) for LN characterization after CRT and to compare the performance with that of LN size.

Fifty-three patients (36 men, 17 women; mean age, 58 years; age range, 34–79 years) who underwent CRT and subsequent surgery were included. All patients underwent 1.5-T magnetic resonance imaging (MRI). Each regional LN on post-CRT MRI was identified in consensus by two radiologists after reviewing the pre-CRT MRI. The ADC value and size in each LN was measured. To compare the mean ADC values and sizes of the metastatic and non-metastatic LNs after CRT, the t-test was used. To calculate the performance, a ROC curve analysis was performed. The histopathological examinations served as the reference standard.

A total of 115 LNs (29 metastatic and 86 non-metastatic) were matched and analyzed. The mean ADC of the metastatic LNs was significantly higher than that of the non-metastatic LNs (1.36 ± 0.27 × 10^–3mm²/s; 1.13 ± 0.23 × 10^–3mm²/s, P < 0.0001). The mean size of the metastatic LNs was also significantly larger than that of the non-metastatic LNs (5.6 ± 3.1; 3.9 ± 1.2, P = 0.0078). There was no significant difference between the areas under the curve of the ADC and size (0.742 [95% CI, 0.652–0.819]; 0.680 [0.586–0.764], respectively, P = 0.4090).

The performance of ADC for LN characterization after CRT was comparable to that of LN size.

Parallel imaging (PI) techniques are used for overcoming lower spatial and time resolution for magnetic resonance imaging (MRI). There is clinical need to overcome inevitable noise by decreased voxel size and signal-to-noise issue by using high-acceleration factor (AF).

To determine whether the combination of a modified Dixon three-dimensional (3D) T1-weighted (T1W) gradient echo technique (mDixon-3D-GRE) and high-acceleration ([HA], AF = 5) PI can provide breath-hold (BH) T1W imaging with better image quality than conventional fat-suppressed 3D-T1W-GRE (SPAIR-3D-GRE) for Gd-EOB-DTPA-enhanced liver MR.

This retrospective study was approved by our institutional review board and informed consent was waived. There were 138 patients who underwent Gd-EOB-DTPA-enhanced liver MR at 3 T using either standard SPAIR-3D-GRE sequences with an AF of 2.6 (n = 68, Standard group) or mDixon-3D-GRE with an AF of 5 (n = 70, HA group). In the HA group, hepatobiliary phase was obtained three times using HA-mDixon-3D-GRE (AF = 5), HA-SPAIR-3D-GRE (AF = 5), and standard-SPAIR-3D-GRE (AF = 2.6). Image noise, quality, and anatomic depiction of dynamic phase were compared between standard and HA groups, and those of hepatobiliary phase were compared among the three image sets in HA group.

As for dynamic imaging, the HA-mDixon-3D-GRE images showed better anatomic details and overall image quality than standard-SPAIR-3D-GRE sequence (arterial phase: 3.56 ± 0.63 vs. 2.66 ± 0.69, P < 0.001). In the intra-individual comparison, HA-mDixon-3D-GRE provided better orang depiction and overall image quality than standard-SPAIR-3D-GRE (3.99 ± 0.75 vs. 3.0 ± 0.72, P < 0.001) and better fat suppression and significantly less noise than HA-SPAIR-3D-GRE (4.76 ± 0.43 vs. 3.71 ± 0.54, P < 0.001).

The combined use of mDixon-3D-GRE sequence and high-acceleration PI provided better quality BH-T1W imaging compared with conventional SPAIR-3D-GRE for Gd-EOB-DTPA-enhanced liver MRI.

Previous studies have correlated the maximum standardized uptake value (SUV_max) of breast cancer lesions with histological and biological characteristics such as tumor size, histologic grade, or hormonal receptor expression status. However, controversy remains concerning the prognostic value of SUV_max in breast cancer.

To determine if the SUV_max of a tumor on 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) is associated with disease-free survival in patients with primary invasive ductal breast cancer.

The institutional review board of our hospital approved this retrospective study. From 2009 to 2011, 508 women (mean age, 53.6 years; age range, 26–85 years) with newly diagnosed invasive ductal breast cancer who had undergone preoperative 18F-FDG PET/CT followed by surgery were identified. Clinicopathological variables and FDG uptake quantified by SUV_max were analyzed. The Cox proportional hazards model was used to evaluate the association between SUV_max and disease-free survival after controlling for clinicopathological parameters.

There were 21 recurrences at a median follow-up of 46 months. The mean SUV_max of the primary tumor was significantly higher in patients with a recurrence than those who remained disease-free (9.5 ± 3.5 vs. 6.6 ± 4.2, P < 0.001). A receiver operating characteristic curve indicated that a SUV_max of 5.95 was the optimal cut-off value to predict disease-free survival. Multivariate analysis identified a high SUV_max (≥5.95) and high T stage as independent significant variables associated with worse disease-free survival.

A high primary tumor SUV_max on 18F-FDG PET/CT was an independent factor associated with worse disease-free survival in patients with primary invasive ductal breast cancer.

Computed tomography angiography (CTA) is the most employed modality in the follow-up after endovascular aneurysm repair (EVAR) of abdominal aorta (AA); repeated standard controls expose patients to a high cumulative radiation dose (RD).

To compare image quality and RD between 100 kV and 120 kV protocols in the same group of patients, previously treated with EVAR.

Thirty patients, who had performed a previous CTA at 120 kV, underwent a low dose CTA with the same 64-detector machine. Images were evaluated qualitatively and quantitatively. The influence of body mass index (BMI), considering three groups of patients (normal weight, overweight, and obese) was also assessed. RD values (volume CT dose index and effective dose) were calculated.

The mean qualitative score at 100 kV was worse than that at 120 kV, but the difference was not statistically significant and in all cases the image quality was satisfactory. At 100 kV the vessels mean attenuation value was significantly higher; signal-to-noise ratio significantly lower; contrast-to-noise ratio lower, but the difference was not significant. Regarding BMI, the difference in the qualitative score was significant in the obese group, but not in the other two groups; of the quantitative parameters only the signal-to-noise ratio presented a significant difference in the obese group. The average CTDIvol was reduced by 22% and the mean effective dose by 36% with the 100 kV protocol compared to the 120 kV protocol. Both differences were significant.

The 100 kV protocol allowed a consistent RD reduction, maintaining a satisfactory image quality in all patients.

Many two-dimensional (2D) morphologic cartilage imaging sequences have disadvantages such as long acquisition time, inadequate spatial resolution, suboptimal tissue contrast, and image degradation secondary to artifacts. IDEAL imaging can overcome these disadvantages.

To compare sound-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and quality of two different methods of imaging that include IDEAL 3D SPGR and 3.0-T FSE T2 fat saturation (FS) imaging and to evaluate the utility of IDEAL 3D SPGR for knee joint imaging.

SNR and CNR of the patellar and femoral cartilages were measured and calculated. Two radiologists performed subjective scoring of all images for three measures: general image quality, FS, and cartilage evaluation. SNR and CNR values were compared by paired Student’s t-tests.

Mean SNRs of patellar and femoral cartilages were 90% and 66% higher, respectively, for IDEAL 3D SPGR. CNRs of patellar cartilages and joint fluids were 2.4 times higher for FSE T2 FS, and CNR between the femoral cartilage and joint fluid was 2.2 times higher for FSE T2 FS. General image quality and FS were superior using FSE T2 FS compared to those of IDEAL 3D SPGR imaging according to both readers, while cartilage evaluation was superior using IDEAL 3D SPGR. Additionally, cartilage injuries were more prominent in IDEAL 3D SPGR than in FSE T2FS according to both readers.

IDEAL 3D SPGR images show excellent visualization of patellar and femoral cartilages in 3.0 T and can compensate for the weaknesses of FSE T2 FS in the evaluation of cartilage injuries.

Muscle hardness indicates muscle condition, and its measurement before and after resistance exercise is essential for preventing resistance training-induced muscle injury.

To investigate muscle hardness of the triceps brachii (TB) before and immediately after a resistance exercise session involving the elbow extensors.

In 18 young men, muscle hardness of the long head of TB was measured at 50%, 60%, and 70% point along the length of the upper arm from the acromial process of the scapula to the lateral epicondyle of the humerus by using shear wave ultrasound elastography. At the same sites, muscle thickness of the long head of TB was also measured by ultrasonography. Resistance exercise was performed using a dumbbell with a mass adjusted to 80% of the one-repetition maximum.

Although the exercise-induced increase in muscle hardness was significant at all the regions, muscle hardness was significantly higher at 70% of the upper arm length than at the other regions before and after resistance exercise. The exercise-induced increase in muscle thickness was also significant, but the relative changes in muscle hardness before and after resistance exercise were not correlated with the corresponding relative changes in muscle thickness at each region. These results indicate the small effect of exercise-induced muscle swelling on exercise-induced changes in muscle hardness.

We suggest that muscle damage and/or injury, particularly at the distal region of TB, should be carefully considered to safely perform resistance exercise.

Humeral head cysts are not uncommon in individuals with rotator cuff disorders. The cysts are usually considered an indicator of rotator cuff pathologies; however, they may have different meanings in different regions.

To determine the frequency of cysts within and adjacent to the lesser tuberosity and the relationship between these cysts and subscapularis, supraspinatus, and long head of the biceps tendon (LHBT) disorders.

We retrospectively reviewed 760 consecutive shoulder magnetic resonance imaging (MRI) examinations. Among these MRIs, we selected a group of patients with cysts located around the lesser tuberosity. The study population was also divided into two subgroups, patients with cysts within the lesser tuberosity and those with cysts adjacent to the lesser tuberosity. In addition to the number and size of cysts, the MRI appearance of the tendons was evaluated.

Eighty-one (10.7%) patients had cysts within and/or adjacent to the lesser tuberosity, 34 (42%) patients had cysts within the lesser tuberosity, and 47 (58%) patients had cysts adjacent to it. LHBT and subscapularis tendon disorders were significantly related to more than one cyst. In a univariate analysis, cysts within the lesser tuberosity were significantly associated with LHBT and subscapularis tendon disorders; however, multivariate analyses showed that only LHBT disorders were significantly associated with cysts within the lesser tuberosity.

Cysts within the lesser tuberosity were less common than cysts adjacent to it. LHBT and subscapularis tendon disorders were more frequently found in patients with more than one cyst within and/or adjacent to the lesser tuberosity. In addition, cysts within the lesser tuberosity were associated with LHBT disorders.

The reliable detection of intracranial hemorrhages is important, but just 1 year after the hemorrhage onset it might be missed using T2-weighted spin-echo and gradient-echo sequences. Susceptibility-weighted imaging (SWI) is a new magnetic resonance imaging sequence that is extremely sensitive in hemorrhage detection and that might improve the detection of hemorrhages over time.

To investigate whether the detectability of intracranial blood and its degradation products is independent of the time span after intracranial hemorrhage using SWI.

Sixty-six consecutive patients (28 men, 38 women) with definitely known time point of intracranial hemorrhage and available SWI sequence (1.5 or 3 T) were analyzed retrospectively. Twenty-one patients had a SWI follow-up. All SWI images were assessed by two radiologists in consensus regarding hemorrhage visibility using a 5-point scale. Statistical analysis was performed using Spearman’s correlation test.

Median time interval between hemorrhage and first available SWI measurement was 819 days (range, 0 days to 13.2 years). Nine of 66 patients had an isolated subarachnoid hemorrhage (iSAH) and were therefore analyzed separately. In eight of these nine patients the hemorrhage could clearly be detected, the remaining one had minor iSAH. Spearman analysis showed no significant correlation between time span and visibility (P = 0.660). In the remaining 57 patients (no iSAH) the hemorrhage was always visible achieving at least 3/5 points on the 5-point scale, and Spearman’s analysis revealed only a weak correlation between time span and visibility (r = 0.493, P < 0.001).

The detectability of blood and its degradation products using SWI is reliably possible over a long period after intracranial hemorrhage.

Familiarity with the variants of the foramina of the orbit and periorbital region is important in planning anesthesiological blocks and during orbital and maxillofacial surgery to avoid damage to nerves and vessels.

To assess the visibility and the incidence of variants of the small foramina of the orbit by multidetector computed tomography (MDCT).

The MDCT scans of 400 orbits from 200 patients were evaluated retrospectively. Slice thickness of the reconstructed images were in the range of 0.5–1.0 mm. The visibility and the variants of the foramen supraorbitale, the foramen infraorbitale, the foramen zygomaticofaciale, the foramen ethmoidale anterius et posterius, and the foramen cranio-orbitale were assessed using three-dimensional reconstruction tools.

The foramen infraorbitale (100%; n = 400), foramen supraorbitale (99.5%, n = 398), foramen zygomaticofaciale (76.5%; n = 307), and foramen zygomatico-orbitale (74.5%; n = 298) were most reliably detected by MDCT, while the foramen ethmoidale anterius (58.7%; n = 235) et posterius (56.7%; n = 225) were depicted less frequently. The foramen cranio-orbitale could not be identified in any case. Doubling was found for the foramen supraorbitale in 3.25% (n = 13), the foramen infraorbitale in 1.75% (n = 7), the foramen zygomaticofaciale in 16% (n = 64), and the foramen zygomatico-orbitale 14% (n = 56). Three foramina zygomatico-orbitale and foramina infraorbitale were found in 1.5% (n = 6) and in 0.5% (n = 2) of orbits, respectively.

The foramina supraorbitale, infraorbitale, zygomatico-orbitale, and zygomaticiofaciale and their variants are well visible on MDCT. Knowledge of the exact number of these small foramina is relevant for preoperative evaluation.

Magnetic resonance imaging (MRI) can be helpful in visualizing neurovascular conflict (NVC) of the trigeminal nerve in patients with trigeminal neuralgia (TN), but the relationship between these two events is controversial.

To investigate whether posterior fossa volume is a predisposing factor for NVC in TN.

We conducted a case-control study of clinically diagnosed idiopathic TN of 30 patients aged 30–79 years and 30 age- and sex-matched controls. We compared the volume of the posterior fossa and subarachnoid space using fast-imaging employing steady-state acquisition MRI and the iPlan® programme of BrainLab.

The posterior fossa volumes in controls and patients with TN were 168.97 cm³ and 167.63 cm³, respectively. A small pontomesencephalic cistern volume was more frequent in TN. However, neither the cisternal nor parenchymal portions of the posterior fossa were different between patients with TN and controls, and no significant volume difference was observed in this study.

Although the hypothesis that small posterior fossa volume influences TN was feasible, we did not find any volumetric differences (including the cisternal and parenchymal volumes).However, small pontomesencephalic cistern volumes were more frequent in patients with TN.

When performing percutaneous radiofrequency ablation (RFA) of small renal masses (SRM), use of optimized periprocedural image guidance is essential to secure curative outcome of the treatment.

To retrospectively compare the short-term radiological and clinical outcomes of RFA under combined ultrasound (US) and computed tomography (CT) guidance with that of a previously performed US-guided series at the same institution.

From November 2009 to November 2013, 60 patients (mean age, 70.1 years; range, 34–86 years) with renal masses measuring in the range of 13–50 mm in maximal diameter (mean diameter, 25.4 ± 6.8 mm) underwent percutaneous RFA with combined US/CT guidance. The technical success rate, recurrence-free survival, rate of complications, and the percentage change in the estimated glomerular filtration rate (eGFR) were compared with that of a previously published series of 41 patients with SRM treated with US-guided RFA between November 2002 and December 2008.

The tumor and patient characteristics were similar between the two treatment groups. The primary and secondary technical success rate was significantly higher in the group treated with combined US/CT guidance compared with the group treated with US guidance alone (100% and 100% vs. 82% and 91%, respectively). The local recurrence-free survival was significantly better in the combined US/CT-guided group than in the US-guided group (P = 0.016). There was no significant difference in the rate of overall complications (13% vs. 17%) or the mean percentage decrease in the eGFR after the respective treatment (1.1 ± 18.3% vs. 5.0 ± 11.7%).

The use of combined US/CT guidance when performing renal RFA resulted in superior primary and short-term outcome compared to the use of US guidance alone in patients treated at the same institution.

Many candidates for kidney transplantation need to undergo vessel examination before the transplantation procedure.

To identify the optimal preoperative modality for the examination of vessel status without the use of contrast agents in kidney transplant candidates.

Fifty-three consecutive patients were examined and 31 patients were transplanted. Ultrasonography (US), non-contrast-enhanced computed tomography (NCCT), and non-contrast-enhanced magnetic resonance angiography (NCMRA) were compared using inspection during kidney transplantation (TX) as a reference standard. The sensitivity and specificity to severe arteriosclerotic changes and the accuracy were calculated. Kappa statistics were used to assess the agreement between TX and the different examination modalities, and McNemar’s test was used to test for significant differences.

US had higher sensitivity (1.0) and better agreement with observations from surgery (k = 0.89) than both NCCT (sensitivity = 0.60; k = 0.72) and NCMRA (sensitivity = 0.20; k = 0.30). No significant difference was found between TX and US (P = 0.3173) or TX and NCCT (P = 0.1573), but there was a significant difference between TX and NCMRA (P = 0.0455). US was inconclusive in 20% of cases, and the internal iliac artery could not be visualized in 69% of cases.

Either US or NCCT can be used as the preferred preoperative imaging modality to examine vessel status before kidney transplantation, but a combination of the two is preferable. NCMRA should not be used as the sole imaging modality for preoperative imaging before kidney transplantation because of its low sensitivity in detecting severe arteriosclerotic disease without the presence of stenosis.