Dosimetric benefits of hemigland stereotactic body radiotherapy for prostate cancer: implications for focal therapy

Objective:

Compared with standard, whole-gland (WG) therapies for prostate cancer, focal approaches may provide equivalent oncologic outcomes with fewer adverse effects. The purpose of this study was to compare organ-at-risk (OAR) dosimetry between hemigland (HG) and WG stereotactic body radiotherapy (SBRT) plans.

Methods:

Volumetric-modulated arc radiotherapy-based SBRT plans were designed to treat the left HG, right HG and WG in eight patients, using five fractions of 8 Gy. OARs of interest included the contralateral HG, rectum, urinary bladder, urethra, penile bulb and contralateral neurovascular bundle.

Results:

Rectal V_80% (the percentage of a normal structure receiving a dose of 80%) and V_90% were significantly lower with HG plans than with WG plans (median values of 4.4 vs 2.5 cm³ and 2.1 vs 1.1 cm³, respectively, p < 0.05 by Student''s t-test). Bladder V_50% was also reduced significantly in HG plans (32.3 vs 17.4 cm³, p < 0.05), with a trend towards reduction of V_100% (3.4 vs 1.3 cm³, p = 0.09). Urethral maximum dose and mean doses to the penile bulb and contralateral neurovascular bundle were also reduced significantly (42.0 vs 39.7 Gy, p < 0.00001; 13.3 vs 9.2 Gy, p < 0.05; and 40.2 vs 19.3 Gy, p < 0.00001, respectively).

Conclusion:

Targeting an HG volume rather than a WG volume when delivering SBRT can offer statistically significant reductions for all OARs. Given the large magnitude of the reduction in dose to these OARs, it is anticipated that HG SBRT could offer a superior toxicity profile when compared with WG SBRT. This is likely to be most relevant in the context of salvaging a local failure after radiation therapy.

Advances in knowledge:

The dosimetric feasibility of HG SBRT is demonstrated. When compared with WG SBRT plans, the HG plans demonstrate statistically significant and large magnitude reduction in doses to the rectum, bladder, urethra, penile bulb and contralateral neurovascular bundle, suggesting the possibility of improved toxicity outcomes with HG SBRT. This is likely to be most relevant in the context of salvaging a local failure after radiation therapy.     

Predictors of late bowel toxicity using three different methods of contouring in patients undergoing post-operative radiation for cervical cancer

Objective:

This study investigates the correlation between dose–volume histogram derived from three bowel contouring methods and late toxicity in patients undergoing post-operative radiation therapy (PORT) for cervical cancer.

Methods:

From June 2010 to May 2013, 103 patients undergoing PORT were included. Three different contouring methods were used: (a) individual small bowel (SB) and large bowel (LB) loops, (b) total bowel (TB; including SB and LB) and (c) peritoneal cavity (PC). The volume of SB, LB, TB and PC receiving 15, 30 and 40 Gy was calculated. Acute and late bowel toxicities were scored using Common Terminology Criteria for Adverse events v. 3.0. Receiver operating characteristic curve identified thresholds predicting late toxicity with the highest specificity. All data were dichotomized across these thresholds. Univariate and multivariate analyses were performed using SPSS^® v. 20 (IBM Corporation, Armonk, NY; formerly SPSS Inc., Chicago, IL).

Results:

On univariate analysis, V₃₀ PC ≥ 900 cm³ (p = 0.01), V₄₀ PC ≥ 750 cm³ (p = 0.03) and V₄₀ TB ≥ 280 cm³ (p = 0.03) and use of concurrent chemotherapy (p = 0.03) predicted grade ≥II acute toxicity. On multivariate analysis, use of concurrent chemotherapy [odds ratio (OR) 3.5, 95% confidence interval (CI) 1.1–11.1, p = 0.03] and V₃₀ PC ≥ 900 cm³ (OR 2.3, 95% CI 1–5.5, p = 0.05) predicted acute grade ≥II toxicity. On univariate analysis for late toxicity, SB (V₃₀ ≥ 190 cm³, p = 0.009; V₄₀ ≥ 150 cm³, p = 0.03), LB (V₁₅ ≥ 250 cm³, p = 0.04), V₄₀ PC (V₄₀ ≥ 750 cm³, p = 0.001) and presence of acute grade ≥III toxicity (p = 0.006), treatment technique (three-dimensional conformal radiation or intensity modulated radiotherapy, p = 0.02) predicted more than or equal to grade ll late bowel toxicity. On multivariate analysis, only body mass index ≥25 kg m⁻² (OR 7.3, 95% CI 1.6–31.6, p = 0.008) and presence of acute grade III toxicity predicted toxicity (OR 5.1, 95% CI 1.4–18.1, p = 0.007).

Conclusion:

V₃₀ PC ≥ 900 cm³ and use of concurrent chemotherapy independently predicts acute toxicity. Presence of acute grade ≥III toxicity independently predicts late toxicity. Minimizing dose to PC subvolumes can therefore reduce both acute and late toxicities.

Advances in knowledge:

Study establishes PC thresholds that can minimize both acute and late bowel toxicities.     

Stereotactic body radiation therapy for a new lung cancer arising after pneumonectomy: dosimetric evaluation and pulmonary toxicity

Objective:

To evaluate the tolerance of stereotactic body radiation therapy (SBRT) for the treatment of secondary lung tumours in patients who underwent previous pneumonectomy.

Methods:

12 patients were retrospectively analysed. The median maximum tumour diameter was 2.1 cm (1–4.5 cm). The median planning target volume was 20.7 cm³ (2.4–101.2 cm³). Five patients were treated with a single fraction of 26 Gy and seven patients with fractionated schemes (3 × 10 Gy, 4 × 10 Gy, 4 × 12 Gy). Lung toxicity, correlated with volume (V) of lung receiving >5, >10 and >20 Gy, local control and survival rate were assessed. Median follow-up was 28 months.

Results:

None of the patients experienced pulmonary toxicity > grade 2 at the median dosimetric lung parameters of V₅, V₁₀ and V₂₀ of 23.1% (range 10.7–56.7%), 7.3% (2.2–27.2%) and 2.7% (0.7–10.9%), respectively. No patients required oxygen or had deterioration of the performance status during follow-up if not as a result of clinical progression of disease. The local control probability at 2 years was 64.5%, and the overall survival at 2 years was 80%.

Conclusion:

SBRT appears to be a safe and effective modality for treating patients with a second lung tumour after pneumonectomy.

Advances in knowledge:

Our results and similar literature results show that when keeping V₅, V₁₀ V₂₀ <50%, <20% and <7%, respectively, the risk of significant lung toxicity is acceptable. Our experience also shows that biologically effective dose 10 >100 Gy, necessary for high local control rate, can be reached while complying with the dose constraints for most patients.     

Dosimetric planning study for the prevention of anal complications after post-operative whole pelvic radiotherapy in cervical cancer patients with hemorrhoids

Objective:

Radiation-induced anal toxicity can be induced by low radiation doses in patients with haemorrhoids. The object of this study was to determine the dosimetric benefits of different whole pelvic radiotherapy (WPRT) techniques in terms of dose delivered to the anal canal in post-operative patients with cervical cancer.

Methods:

The planning CT images of 10 patients with cervical cancer undergoing postoperative radiotherapy were used for comparison of three different plans. All patients had been treated using the conventional box technique WPRT (CV-WPRT), and we tried low-margin-modified WPRT (LM-WPRT), three-dimensional conformal techniques WPRT (CF-WPRT) and intensity-modulated WPRT (IM-WPRT) planning for dosimetric comparison of the anal canal, retrospectively.

Results:

Mean anal canal doses of the IM-WPRT were significantly lower (p < 0.05) than those of CV-WPRT, LM-WPRT and CF-WPRT, and V₁₀, V₂₀, V₃₀ and V₄₀ to the anal canal were also significantly lower for IM-WPRT (p < 0.05). The proportion of planning target volumes (PTVs) that received ≥98% of the prescribed dose for all plans was >99%, and the proportion that received ≥108% of the prescribed dose for IM-WPRT was <2%. Volumes of bladders and rectums that received ≥30 or ≥40 Gy were significantly lower for IM-WPRT than for three of the four-field WPRT plans (p = 0.000).

Conclusion:

IM-WPRT can significantly reduce radiation dose delivered to the anal canal and does not compromise PTV coverage. In patients with haemorrhoids, IM-WPRT may be of value for the prevention of anal complications.

Advances in knowledge:

Although tolerance of the anal canal tends to be ignored in patients undergoing post-operative WPRT, patients with haemorrhoids may suffer complications at low radiation doses. The present study shows IM-WPRT can be meaningful in these patients.     

Dosimetric effects of roll rotational setup errors on lung stereotactic ablative radiotherapy using volumetric modulated arc therapy

Objective:

To evaluate the dosimetric effects of roll-rotational setup errors of stereotactic ablative radiotherapy (SABR) for lung cancer using volumetric modulated arc therapy (VMAT).

Methods:

A total of 23 lung SABR cases were evaluated retrospectively. Each of the planning CT images was intentionally rotated by ±1°, ±2° and ±3°. After that, to simulate the translational couch correction, rotated CT images were moved along the x, y and z axis to match the centroid of the target volume in the rotated CT images with that in the original CT images. The differences in D_95% and V_100% of the target volume, D_0.35cc of spinal cord, D_0.35cc and D_5cc of oesophagus and V_20Gy of lung between the original and the rotated CT images were calculated.

Results:

The average differences in D_95% and V_100% of target volume, D_0.35cc of spinal cord, D_0.35cc and D_5cc of oesophagus and V_20Gy of lung were −0.3% ± 0.4% and −0.7% ± 2.4%, 1.6 ± 27.9 cGy, −1.6 ± 37.6 cGy, 15.9 ± 25.3 cGy and 0.0% ± 0.1%, respectively. The dosimetric changes in organs at risk (OARs) near the target volume were sometimes considerable due to roll-rotational setup errors, despite the translational correction, and those were patient specific.

Conclusion:

In the case of coplanar VMAT for lung SABR, dosimetric changes to the target volume due to roll-rotational setup errors could be compensated by translational correction, whereas those to the OARs could not in some cases.

Advances in knowledge:

Roll-rotational setup errors would increase the dose to OARs despite the translational correction.     

Correlation between anthropometric parameters and acute skin toxicity in breast cancer radiotherapy patients: a pilot assessment study

Objective:

The objective of the present study was to identify acute skin toxicity risk factors linked to the anthropometric characteristics of patients with breast cancer treated with radiation therapy.

Methods:

Consecutive patients with breast cancer were enrolled after breast-conserving surgery and before radiotherapy course. Acute skin toxicity was assessed weekly during the 7 weeks of radiotherapy with the International Classification from National Cancer Institute. Grade 2 defined acute skin toxicity. Patient characteristics and anthropometric measurements were collected.

Results:

54 patients were enrolled in 2013. Eight patients (14.8%) had grade ≥2 toxicity. The average weight and chest size were 65.5 kg and 93.6 cm, respectively. Bra cup size is significantly associated with a risk of grade 2 dermatitis [odds ratio (OR) 3.46, 95% confidence interval (CI) (1.29–11.92), p = 0.02]. Anthropometric breast fat mass measurements, such as thickness of left [OR 2.72, 95% CI (1.08–8.26), p = 0.04] and right [OR 2.45, 95% CI (0.99–7.27), p = 0.05] axillary fat, are correlated with an increased risk. Distance between the pectoral muscle and nipple is a reproducible measurement of breast size and is associated with acute skin toxicity with significant tendency (OR = 2.21, 95% CI (0.97–5.98), p = 0.07).

Conclusion:

Breast size and its different anthropometric measurements (thickness of left and right axillary fat, nipple-to-pectoral muscle distance) are correlated with the risk of skin toxicity.

Advances in knowledge:

The present article analyses several characteristics and anthropomorphic measurements of breast in order to assess breast size. A standardized and reproducible protocol to measure breast volume is described.     

Comparative study of CT appearances in mucinous tubular and spindle cell carcinoma and collecting duct carcinoma of the kidney

Objective:

To characterize the multidetector CT (MDCT) imaging characteristics of mucinous tubular and spindle cell carcinoma (MTSCC) and collecting duct carcinoma (CDC) of the kidney.

Methods:

21 patients with MTSCC and 18 patients with CDC were studied retrospectively. MDCT was undertaken to investigate differences in tumour characteristics.

Results:

Five patients with MTSCC had calcifications as did nine patients with CDC (p = 0.108). In three patients with MTSCC and four patients with CDC, the tumours had a clear boundary (p = 0.682). No patient with MTSCC had retroperitoneal lymph node metastasis as did five patients with CDC (p = 0.015). 16 patients with MTSCC showed homogeneous enhancement, whereas 11 patients with CDC showed heterogeneous enhancement (p = 0.025). The attenuation value of CDC tumours was greater than that of MTSCC and normal renal parenchyma on an unenhanced CT (p = 0.027). MTSCC and CDC tumour enhancement was less than the normal renal cortex and medulla in all phases (p < 0.001). Tumour enhancement was greater for CDC than that for MTSCC in all phases (p = 0.011, p = 0.006 and p = 0.052).

Conclusion:

Unenhanced and dynamic MDCT may aid in diagnosis and differentiation of MTSCC and CDC of the kidney.

Advances in knowledge:

This is the first series evaluating the imaging findings of MTSCC and CDC of which we are aware, and identification of such findings may improve diagnosis of these two rare tumours.     

The value of intratumoral heterogeneity of 18F-FDG uptake to differentiate between primary benign and malignant musculoskeletal tumours on PET/CT

Objective:

The cumulative standardized uptake value (SUV)–volume histogram (CSH) was reported to be a novel way to characterize heterogeneity in intratumoral tracer uptake. This study investigated the value of fluorine-18 fludeoxyglucose (¹⁸F-FDG) intratumoral heterogeneity in comparison with SUV to discriminate between primary benign and malignant musculoskeletal (MS) tumours.

Methods:

The subjects comprised 85 pathologically proven MS tumours. The area under the curve of CSH (AUC-CSH) was used as a heterogeneity index, with lower values corresponding with increased heterogeneity. As 22 tumours were indiscernible on ¹⁸F-FDG positron emission tomography, maximum standardized uptake value (SUV_max), mean standardized uptake value (SUV_mean) and AUC-CSH were obtained in 63 positive tumours. The Mann–Whitney U test and receiver operating characteristic (ROC) analysis were used for analyses.

Results:

The difference between benign (n = 35) and malignant tumours (n = 28) was significant in AUC-CSH (p = 0.004), but not in SUV_max (p = 0.168) and SUV_mean (p = 0.879). The sensitivity, specificity and accuracy for diagnosing malignancy were 61%, 66% and 64% for SUV_max (optical threshold value, >6.9), 54%, 60% and 57% for SUV_mean (optical threshold value, >3) and 61%, 86% and 75% for AUC-CSH (optical threshold value, ≤0.42), respectively. The area under the ROC curve was significantly higher in AUC-CSH (0.71) than SUV_max (0.60) (p = 0.018) and SUV_mean (0.51) (p = 0.005).

Conclusion:

The heterogeneity index, AUC-CSH, has a higher diagnostic accuracy than SUV analysis in differentiating between primary benign and malignant MS tumours, although it is not sufficiently high enough to obviate histological analysis.

Advances in knowledge:

AUC-CSH can assess the heterogeneity of ¹⁸F-FDG uptake in primary benign and malignant MS tumours, with significantly greater heterogeneity associated with malignant MS tumours. AUC-CSH is more diagnostically accurate than SUV analysis in differentiating between benign and malignant MS tumours.     

CT coronary angiography in atrial fibrillation: a comparison of radiation dose and diagnostic confidence with retrospective gating vs prospective gating with systolic acquisition

Objective:

To compare unmodulated, retrospective electrocardiographic (ECG) gating to prospective ECG gating with systolic acquisition for CT coronary angiography (CTCA) in patients with atrial fibrillation (AF), considering the radiation dose and the diagnostic confidence achieved with each technique.

Methods:

A retrospective service evaluation was conducted before and after prospective gating with systolic acquisition replaced retrospectively gated imaging for patients with AF undergoing CTCA at our institution. 25 consecutive patients were examined in each group. The scan parameters and radiation dose information had been collected in a prospective fashion. The image sets were read by blinded, expert readers who rated their diagnostic confidence using a 5-point Likert scale.

Results:

The radiation dose received by patients was significantly greater in the retrospectively gated group than those being scanned using prospective gating (21 vs 5.9 mSv, p < 0.01). The prospective gating technique was also associated with greater diagnostic confidence (mean, per-patient score 3.09 vs 3.78, p = 0.02).

Conclusion:

Prospective gating with systolic acquisition appears to improve diagnostic confidence at a significantly reduced radiation dose compared with retrospective gating in patients with AF.

Advances in knowledge:

The use of prospective gating with systolic triggering significantly reduces the radiation exposure to patients in AF undergoing CTCA. The same protocol also appears to improve diagnostic confidence.     

Using the CT features to differentiate invasive pulmonary adenocarcinoma from pre-invasive lesion appearing as pure or mixed ground-glass nodules

Objective:

To differentiate pre-invasive lesion from invasive pulmonary adenocarcinoma (IPA) appearing as ground-glass nodules (GGNs) using CT features.

Methods:

149 GGNs were enrolled in this study, with 74 pure GGNs (p-GGNs) and 75 mixed GGNs (m-GGNs). Firstly, univariate analysis was used to analyse the difference of CT features between pre-invasive lesion and IPA. Then, multivariate analysis was conducted to identify variables that could independently differentiate pre-invasive lesion from IPA. Receiver operating characteristic curve analysis was performed to evaluate the differentiating value of identified variables.

Results:

In the p-GGNs, multivariate analysis showed that the amount of blood vessels was an independent risk factor. Using the amount of blood vessels “≥1” as the diagnostic criterion, we could diagnose IPA with a sensitivity of 100%. Using the amount of blood vessels “=0” as the diagnostic criterion, we could diagnose pre-invasive lesions with a specificity of 100%. In the m-GGNs, multivariate analysis showed that the volume of solid portion (V_Solid) and pleural indentation were two independent risk factors. One further model was constructed using these two variables: model = 2.508 × (V_Solid + 1.407) × (pleural indentation − 1.016). Using the new model, improved diagnostic ability was achieved compared with using V_Solid or pleural indentation alone.

Conclusion:

The amount of blood vessels through the p-GGNs would be an important criterion during clinical management, while V_Solid and pleural indentation seemed important for m-GGNs. Moreover, the new model could further improve the differentiating value for m-GGNs.

Advances in knowledge:

CT features are useful in differentiating pre-invasive lesion from IPA appearing as GGNs.     

Acute effects of pelvic irradiation on the adult uterus revealed by dynamic contrast-enhanced MRI

Objective:

Pelvic radiation therapy (RT) can influence fertility in female rectal cancer survivors. Data regarding its effects on the adult uterus are scant. This study aims to evaluate the uterus before and after RT, using dynamic contrast-enhanced MRI.

Methods:

Eligible patients (n=10) received RT for rectal cancer, had an intact uterus and underwent dynamic contrast-enhanced MRI before and after RT. Seven patients were pre-menopausal.

Results:

Patients received pelvic RT (median, 50.2 Gy) with concurrent 5-fluorouracil. Five patients were treated with intensity modulated RT (IMRT) and five with a three-field technique. The median D95 of the uterus was 30 Gy; D05 was 48 Gy; and V95 was 97%. The median cervical D95 was 45 Gy; D05, 50 Gy; and V95, 100%. Cervical dose was higher with IMRT than with three-field plans (p≤0.038). On T₂ MRI, the junctional zone was visible in nine patients before and in one after RT (p=0.001). Median cervical length (2.3 vs 3.0 cm) and endometrial thickness (2.6 vs 5.9 mm) were reduced after RT (p≤0.008). In pre-menopausal patients, the volume transfer constant, K_trans, (0.069 vs 0.195, p=0.006) and the extracellular extravascular volume fraction, V_e, (0.217 vs 0.520, p=0.053) decreased.

Conclusion:

Pelvic RT significantly affected uterine anatomy and perfusion. Cervical dose was higher with IMRT than three-field plans, but no attempt was made to constrain the dose.

Advances in knowledge:

Pelvic RT significantly affects the adult uterus. These findings are crucial to understand the potential consequences of RT on fertility, and they lay the groundwork for further prospective studies.As the cure rate in locally advanced rectal cancer continues to improve, understanding the long-term sequelae of therapy is gaining importance. Research has shown that young cancer survivors are concerned about treatment-related effects on fertility, pregnancy and neonatal outcomes [1,2]. Previously, pelvic irradiation, standard in the management of locally advanced rectal cancer, invariably caused sterility in females as a result of acute ovarian failure. Currently, however, the risk of ovarian dysfunction may be greatly reduced by transposing the ovaries to the paracolic gutters before radiation therapy (RT) [3]. Additionally, an increasing number of females undergo embryo or oocyte cryopreservation before receiving RT [4]. These advances prompt the question: if a young female has undergone pelvic RT, can she carry a pregnancy to term?Answering this question requires an understanding of the effects of the pelvic RT on the uterus. Ultrasounds of paediatric cancer survivors suggest that pelvic RT alters uterine volume, distensibility and vasculature, with patients who are younger at the time of RT being the most vulnerable to these effects [5–7]. Additionally, population-based studies of paediatric cancer survivors have demonstrated an association between abdominal and/or pelvic RT and adverse pregnancy and neonatal outcomes, including placental abnormalities, pre-term delivery, low birth weight infants and perinatal mortality [8–11]. However, only sparse data exist regarding the effects of pelvic RT on the adult uterus, which may be more radioresistant.The aim of this study was to use dynamic contrast-enhanced (DCE) MRI to assess the acute effects of RT on the uterus in females treated for locally advanced rectal cancer. A second aim was to compare dosimetric parameters of conventional three-field RT and intensity modulated RT (IMRT) treatment plans.     

A quantitative analysis of 1H-MR spectroscopy at 3.0?T of three brain regions from childhood to middle age

Objective:

To study age-related metabolic changes in different brain regions.

Methods:

Point-resolved spectroscopy (repetition time/echo time = 2000 ms/30 ms) was performed in the left and right hippocampus, the left thalamus and the left centrum semiovale of 80 healthy subjects (37 females and 43 males aged 7–64 years). Analysis of covariance and linear regression were used for statistical analysis. Both metabolite concentration ratios with respect to total creatine (tCr) and absolute metabolite concentrations were included for analysis.

Results:

Ins (myo-inositol)/tCr (p < 0.001) and absolute Ins concentration (p = 0.031) were significantly increased with age after adolescence. NAA (N-acetylaspartic acid)/tCr (p < 0.001) and absolute NAA concentration (p = 0.010) significantly declined with age after adolescence.

Conclusion:

Age-related increase of Ins and decline of NAA are found in all three regions, especially at the hippocampus, indicating possible gliosis in the ageing brain.

Advances in knowledge:

We could use NAA/tCr and Ins/tCr as an indicator to estimate the neurons-to-glial cells ratio at the thalamus. This may be an index to distinguish normal tissues from gliosis.     

Changes in dynamic contrast-enhanced pharmacokinetic and diffusion-weighted imaging parameters reflect response to anti-TNF therapy in Crohn's disease

Objective:

To investigate the effect of tumour necrosis factor (TNF)-α antagonists on MRI dynamic contrast-enhanced (DCE) and diffusion-weighted imaging (DWI) parameters in Crohn''s disease (CD).

Methods:

42 patients with CD (median age 24 years; 22 females) commencing anti-TNF-α therapy with baseline and follow-up (median 51 weeks) 1.5-T MR enterography (MRE) were retrospectively identified. MRE included DCE (n = 20) and/or multi-b-value DWI (n = 17). Slope of enhancement (SoE), maximum enhancement (ME), area under the time–intensity curve (AUC), K_trans (transfer constant), v_e (fractional volume of the extravascular–extracellular space), apparent diffusion coefficient (ADC) and ADC_fast/slow were derived from the most inflamed bowel segments. A physician global assessment of disease activity (remission, mild, moderate and severe) at the time of MRE was assigned, and the cohort was divided into responders and non-responders. Data were compared using Mann–Whitney U test and analysis of variance.

Results:

Follow-up K_trans, ME, SoE, AUC and ADC_ME changed significantly in clinical responders but not in non-responders, baseline {[median [interquartile range (IQR)]: 0.42 (0.38), 1.24 (0.52), 0.18 (0.17), 17.68 (4.70) and 1.56 mm² s⁻¹ (0.39 mm² s⁻¹) vs follow-up [median (IQR): 0.15 (0.22), 0.50 (0.54), 0.07 (0.1), 14.73 (2.06) and 2.14 mm² s⁻¹ (0.62 mm² s⁻¹), for responders, respectively, p = 0.006 to p = 0.037}. SoE was higher and ME and AUC lower for patients in remission than for those with severe activity [mean (standard deviation): 0.55 (0.46), 0.49 (0.28), 14.32 (1.32)] vs [0.32 (0.37), 2.21 (2.43) and 23.05 (13.66), respectively p = 0.017 to 0.033]. ADC was significantly higher for patients in remission [2.34 mm² s⁻¹ (0.67 mm² s⁻¹)] than for those with moderate [1.59 mm² s⁻¹ (0.26 mm² s⁻¹)] (p = 0.005) and severe disease [1.63 mm² s⁻¹ (0.21 mm² s⁻¹)] (p = 0.038).

Conclusion:

DCE and DWI parameters change significantly in responders to TNF-α antagonists and are significantly different according to clinically defined disease activity status.

Advances in knowledge:

DCE and DWI parameters change significantly in responders to TNF-α antagonists in CD, suggesting an effect on bowel wall vascularity.     

Differential Findings of Tc-99m Sestamibi Dual-Phase Parathyroid Scintigraphy Between Benign and Malignant Parathyroid Lesions in Patients with Primary Hyperparathyroidism

Purpose

This study aimed to investigate the differential findings in clinical and biochemical features, and Tc-99m sestamibi (MIBI) dual-phase parathyroid scintigraphy for malignant and benign parathyroid lesions in patients with primary hyperparathyroidism.

Methods

Subjects were 102 parathyroid lesions from 91 patients with primary hyperparathyroidism. Scintigraphic findings included radioactivity grade, uptake pattern, uptake contour, lesion size on early and delayed images, and degree of washout. Clinical and biochemical features were also evaluated. Histopathology confirmed the final diagnosis for all the patients.

Results

Final diagnoses were 94 benign parathyroid lesions and 8 parathyroid carcinomas. The patients with parathyroid carcinoma were significantly older (p = 0.002) and had significantly higher serum parathyroid hormone concentrations than those with benign parathyroid lesions (p < 0.001). All malignant parathyroid lesions showed intense radioactivity similar to or greater than the submandibular gland activity on delayed images (p = 0.007), and little radioactivity difference between early and delayed images (p = 0.012). The cancer incidence for parathyroid lesions with both intense radioactivity and no washout was 17.0% (8/47). When parathyroid lesions with all of the above-mentioned findings were regarded as malignant, the cancer incidence significantly increased from 17.0% to 33.3% (8/24, p < 0.001).

Conclusion

For Tc-99m MIBI dual-phase parathyroid scintigraphy, uptake grade on delayed images and washout were significantly useful diagnostic criteria for differentiating benign from malignant parathyroid lesions, along with age and parathyroid hormone serum concentration.     

Consequences of additional use of contrast-enhanced 18F-FDG PET/CT in target volume delineation and dose distribution for pancreatic cancer

Objective:

To compare the differences between contrast-enhanced (CE) fluorine-18 fludeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/CT and CECT in target volume delineation and radiotherapy (RT) dose distribution, and to evaluate the sparing of organs at risk (OARs) in the treatment plan of locally advanced pancreatic cancer (LAPC).

Methods:

21 consecutive patients with LAPC with histologically or cytologically confirmed adenocarcinoma underwent both non-CECT and ¹⁸F-FDG scans; 11 of whom also underwent CECT scans. Intensity-modulated RT plans (prescribed dose, 54 Gy) were constructed to cover the corresponding gross tumour volume (GTV). The differences among GTV_CT, GTV_PET, GTV_PET-CT and OARs in these different image sets as well as the uniformity of target dose were analysed.

Results:

The mean non-CE GTV_CT, GTV_PET and GTV_PET-CT were 76.9 ± 47.8, 47.0 ± 40.2 and 44.5 ± 34.7 cm³ (mean ± standard deviation), respectively. The non-CE GTV_PET-CT was significantly smaller than the non-CE GTV_CT (p < 0.001). The CE GTV_PET-CT was significantly smaller than the CE GTV_CT (p = 0.033). For both the non-CE GTV_CT and the CE GTV_CT, the intestine V₄₀ (the percentage of the intestine volume irradiated by 40 Gy), intestine V₅₀, intestine D_max (the mean maximum dose), cord D_max, left kidney V₃₀, right kidney V₃₀, left kidney D_mean (the mean dose), right kidney D_mean and liver V₃₀ were 5.90%, 2.52%, 5500 cGy, 2194 cGy, 3.40%, 0.68%, 747 cGy, 550 cGy and 5.37%, respectively. There are significant differences between the non-CE CT and the non-CE PET-CT in intestine D_max (p = 0.023) and right kidney D_mean (p = 0.029).

Conclusion:

Co-registration of ¹⁸F-FDG PET with CECT may improve the accuracy of GTV delineation in LAPC and might reduce the adverse effect of irradiation.

Advances in knowledge:

Individual adaptation of RT based on functional CE ¹⁸F-FDG PET/CT imaging is possible and highly promising in LAPC.Pancreatic cancer (PC) is the fourth most common cause of cancer death in the USA with 5-year overall survival (OS) rates of <5%.¹ PC is a notoriously insidious disease, and about 70% of patients newly diagnosed with this malignancy are not amenable to curative surgery.² Concurrent chemoradiotherapy is the main treatment for locally advanced or recurrent PC, and radiotherapy (RT) plays a key role for local control. There are still many unresolved issues related to the delineation of the gross tumour volume (GTV) in locally advanced PC (LAPC), such as the difficulty in distinguishing the vasculature from tumour parenchyma, defining the tumour boundary on contrast-enhanced CT (CECT) in the absence of functional positron emission tomography (PET) imaging, and the presence of adjoining organs at risk (OARs), such as the small intestine, spinal cord, kidney and liver. The delineation of the GTV based on PET-CT fusion images could improve RT planning by reducing the target volume and the exposure volumes of the respective OARs and safely escalating the target radiation dose. Conventional enhanced CT scanning could not identify the extent of local tumour and lymph node invasion from peripheral structures precisely,³ which may result in inaccurate target delineation.Our study aimed to explore the value of the CE fluorine-18 fludeoxyglucose (¹⁸F-FDG) PET-CT fusion images for target volume delineation, dose distribution in OARs and the uniformity of target dose compared with the results of CT scan-based plans in LAPC.     

Biliary dilatation in the presence of a periampullary duodenal diverticulum

Objective:

Periampullary diverticulum (PAD) often presents as an incidental CT finding. Its significance and its effect on biliary dilation are unclear. The aim of our study was to determine if the presence of a PAD is associated with abnormal dilation of the common bile duct (CBD).

Methods:

Patients with PAD were retrospectively identified from the radiology database from November 2011 to November 2012 and those with known pancreaticobiliary pathology were excluded, except patients with cholelithiasis and prior cholecystectomy. A total of 150 patients with PAD were selected as well as a control group of 150 patients with no PAD. Data with respect to demographics, PAD size and location, ductal diameter, previous cholecystectomy and liver function tests were collected. To compare the groups, the Student''s t-test and χ² analysis were used where appropriate.

Results:

The male : female ratio was 1 : 1.2 with a median average of 71 years in the PAD group. There was no statistical difference in the CBD measurement (at the pre-ampulla and pancreatic head, and distal to confluence) between the PAD and control groups (4.8, 6.9 and 6.8 mm for the PAD group; 4.7, 6.8 and 6.4 mm for the control group; p = 0.5, 0.7 and 0.3). Also, no difference was observed in the right and left intrahepatic biliary ducts (2.7, 2.7 mm for the PAD group; 2.5, 2.6 mm for the control group; p = 0.2, 0.6). There was a significantly higher incidence of cholecystectomy history (23% vs 8.7%, p < 0.01) and cholelithiasis (22% vs 11%, p < 0.01) in the PAD group, and no difference in the liver function tests. Subgroup analysis of small vs large PAD (<20 mm, ≥20 mm) did not show a difference in the CBD and intrahepatic biliary duct measurements. When comparing cholecystectomy vs non-cholecystectomy groups, CBD measurements were significantly higher in the cholecystectomy group.

Conclusion:

Our study confirms that PAD on its own does not lead to abnormal CBD dilatation. However, increased incidence of cholelithiasis and cholecystectomy was noted in the presence of PAD.

Advances in knowledge:

PAD on its own does not cause CBD dilatation.     

Prognostic Significance of Metabolic Tumor Volume Measured by 18F-FDG PET/CT in Operable Primary Breast Cancer

Purpose

We investigated whether PET indices measured by ¹⁸ F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) can predict prognosis in patients with operable primary breast cancer.

Methods

We reviewed 53 patients with operable primary breast cancer who underwent pretreatment FDG PET/CT. PET indices, maximum standardized uptake value (SUV) and metabolic tumor volume (MTV), were measured in the primary breast tumor (P), metastatic lymph nodes (N) and total tumor (T). The Cox proportional hazards model was used with age, tumor size, clinical lymph node status, method of surgery, presence or absence of neoadjuvant chemotherapy, histological type, histological grade, hormone receptors and HER2 status to predict disease-free survival (DFS) and overall survival (OS).

Results

Median follow-up period was 50 months (range, 17–73 months), during which 17 patients had recurrent disease and nine of whom died. The univariate analysis showed that high SUV of N (N_SUV, P = 0.011), MTV of N (N_MTV, P = 0.011) and MTV of T (T_MTV, P = 0.045) as well as high histological grade (P = 0.008), negative estrogen (P = 0.045) and negative progesterone (P = 0.029) receptor status were associated with shorter DFS. High N_SUV (P = 0.035), N_MTV (P = 0.035) and T_MTV (P = 0.035) as well as high histological grade (P = 0.012) and negative estrogen receptor status (P = 0.009) were associated with shorter OS. N_SUV, N_MTV and T_MTV were found to be significantly associated with high histological grade (P = 0.005). However, those failed to be statistically significant prognostic factors on multivariate analysis.

Conclusions

PET indices seem to be useful in the preoperative evaluation of prognosis in patients with operable primary breast cancer. N_SUV, N_MTV and T_MTV might be considerable factors associated with patient outcome in operable breast cancer.     

Evaluation of lung cancer by enhanced dual-energy CT: association between three-dimensional iodine concentration and tumour differentiation

Objective:

To investigate the correlation between iodine concentration of dual-energy CT (DECT) and histopathology of surgically resected primary lung cancers.

Methods:

We reviewed the medical records, post-operative pathological records and pre-operative DECT images of patients who underwent surgical lung resection for primary lung cancer. After injection of iodinated contrast media, arterial and delayed phases were scanned using 140- and 80-kV tube voltages. Three-dimensional iodine concentration (iodine volume) of primary tumours was calculated using lung nodule application software.

Results:

A total of 60 patients (37 males and 23 females; age range, 39–84 years; mean age, 69 years) with 62 lung cancers were analysed. The resected tumours were histopathologically classified into well-differentiated (G1; n = 20), moderately differentiated (G2; n = 29), poorly differentiated (G3; n = 9) and undifferentiated (G4; n = 4) groups by degree of tumour differentiation (DTD). The mean ± standard deviation of iodine volume at the delayed phase was 59.6 ± 18.6 HU in G1 tumours, 46.5 ± 11.3 HU in G2 tumours, 34.3 ± 15.0 HU in G3 tumours and 28.8 ± 6.4 HU in G4 tumours; significant differences were observed between groups (p < 0.001). Univariate logistic regression analysis showed that iodine volumes both at the early and delayed phases were significantly correlated with DTD (p = 0.006 and p = 0.001, respectively), whereas gender, body weight and tumour size were not (p = 0.084, p = 0.062 and p = 0.391, respectively).

Conclusion:

The iodine volume of lung cancers was significantly associated with their DTD. High-grade tumours tended to have lower iodine volumes than low-grade tumours.

Advances in knowledge:

Iodine volume measured by DECT could be a valuable functional imaging method to estimate differentiation of primary lung cancer.