Development of machine learning models for the surveillance of colon surgical site infections

BACKGROUND

Conventional surgical site infection (SSI) surveillance is labour-intensive. We aimed to develop machine learning (ML) models for the surveillance of SSIs for colon surgery and to assess whether the ML could improve surveillance process efficiency.

METHODS

This study included cases who underwent colon surgery at a tertiary center between 2013 and 2014. Logistic regression and four ML algorithms including random forest (RF), gradient boosting (GB), and neural networks (NNs) with or without recursive feature elimination (RFE) were first trained on the entire cohort, and then re-trained on cases selected based on a previous rule-based algorithm. We assessed model performance based on the area under the curve (AUC), sensitivity, and positive predictive value (PPV). The estimated proportion of reduction in workload for chart review based on the ML models was evaluated and compared with the conventional method.

RESULTS

At a sensitivity of 95%, the NN with RFE using 29 variables had the best performance with an AUC of 0.963 and PPV of 21.1%. When combining both the rule-based algorithm and ML algorithms, the NN with RFE using 19 variables had a higher PPV (28.9%) than with the ML algorithm alone, which could decrease the number of cases requiring chart review by 83.9% compared with the conventional method.

CONCLUSION

We demonstrated that ML can improve the efficiency of SSI surveillance for colon surgery by decreasing the burden of chart review while providing high sensitivity. In particular, the hybrid approach of ML with a rule-based algorithm showed the best performance in terms of PPV.

Clinicopathological Outcomes in Patients With Locally Advanced Rectal Cancer Undergoing Preoperative Short-Versus Long-course Chemoradiotherapy With Delayed Surgery

BACKGROUND/AIM

We aimed to compare the clinicopathological outcomes in patients with locally advanced rectal cancer after short- or long-course concurrent chemoradiotherapy (CCRT) followed by delayed surgery.

PATIENTS AND METHODS

The records of 94 patients with cT3-4N0-2M0 rectal cancer who received CCRT between 2010 and 2017 were reviewed. Short-course radiotherapy (RT) was delivered with a median total dose of 25 Gy in five fractions (n=27), and long-course RT was delivered with a median total dose of 50.4 Gy in 28 fractions (n=67). The following concurrent chemotherapy regimens were administered: 5-fluorouracil plus leucovorin in 58 and capecitabine in 24; in 12 cases agents were unknown. The median interval between CCRT and surgery was 8 weeks. Adjuvant chemotherapy was administered after surgery in 80 patients (5-fluorouracil plus leucovorin, n=54; capecitabine, n=9; other, n=14; and unknown, n=3). Propensity-score matching analysis was conducted.

RESULTS

The median follow-up duration was 4.3 years. There were no statistically significant differences between the short- and long-course RT groups in sphincter preservation (85.2% vs. 92.5%, p=0.478), pathological complete remission (18.5% vs. 14.9%, p=0.905), downstaging (44.4% vs. 26.9%, p=0.159), and negative circumferential resection margin (92.6% vs. 89.6%, p=0.947) rates. No differences were found in survival outcomes between the short- and long-course groups at 3 years (overall survival: 91.8% vs. 88.1%, p=0.790; disease-free survival, 75.2% vs. 72.5%, p=0.420; locoregional relapse-free survival, 90.5% vs. 98.4%, p=0.180; and distant metastasis-free survival, 79.6% vs. 73.5%, p=0.490). Similar results were observed after PSM.

CONCLUSION

Clinically, short-course CCRT may be a feasible alternative to long-course CCRT in patients with locally advanced rectal cancer.

Safety of hypofractionated volumetric modulated arc therapy for early breast cancer: A preliminary report

The present study attempts to evaluate the acute and subacute toxicities of hypofractionated volumetric modulated arc therapy (HFX-VMAT) in patients with early breast cancer (EBC). It is a retrospective analysis of 23 patients treated with HFX-VMAT after breast-conserving surgery between September 2021 and February 2022. A total dose of 50.05 to 52.55 Gy was delivered, consisting of 40.05 Gy to the ipsilateral whole breast in 15 fractions of 2.67 Gy and a tumor bed boost dose of 10-12.5 Gy in 4-5 fractions. The primary endpoint was acute/subacute radiation pneumonitis (RP). The secondary endpoint was poor cosmesis, indicating acute/subacute radiation dermatitis. Chest computed tomography (CT) and the Common Terminology Criteria for Adverse Events v.5.0 were used to assess acute and subacute RP and dermatitis, respectively, during radiotherapy (RT) and at 3- and 6-months post-RT. The median follow-up duration was 3.8 months (range, 2.3-4.2). A total of seven patients developed RP. None of these patients presented RP-related symptoms; the diagnosis was based on radiologic findings observed on follow-up chest CT. Among the seven patients with RP, five had right-sided, and two had left-sided breast tumors (71.4 vs. 28.6%; P=0.026). Grade 1 erythema was observed in 19 patients (82.6%) and grade 2 erythema in four (17.4%). The mean target dose, D_105% (the dose received by 105% of the target volume), homogeneity index, mean lung dose, ipsilateral lung V₂₀ (the percentage volume receiving 20 Gy), and V₃₀ (the percentage volume receiving 30 Gy) for ipsilateral whole breast RT were significantly associated with RP (P=0.039, 0.047, 0.018, 0.015, 0.018 and 0.003, respectively.). HFX-VMAT showed tolerable acute/subacute toxicities. Therefore, HFX-VMAT is an effective and safe treatment option for EBC.

Prostate only radiotherapy using external beam radiotherapy: A clinician’s perspective

Prostate-only radiotherapy (PORT) is widely used as the definitive treatment for localized prostate cancer. Prostate cancer has an α/β ratio; therefore, radiotherapy (RT) with a large fraction size is biologically effective for tumor control. The current external beam RT technique for PORT has been improved from three-dimensional conformal RT to intensity-modulated, stereotactic body, and image-guided RTs. These methods are associated with reduced radiation exposure to normal tissues, decreasing urinary and bowel toxicity. Several trials have shown improved local control with dose escalation through the aforementioned methods, and the efficacy and safety of intensity-modulated and stereotactic body RTs have been proven. However, the management of RT in patients with prostate cancer has not been fully elucidated. As a clinician, there are several concerns regarding the RT volume and dose considering the patient’s age and comorbidities. Therefore, this review aimed to discuss the radiobiological basis and external beam technical advancements in PORT for localized prostate cancer from a clinician’s perspective.

A multi-institutional and case-matched control study on treatment outcomes of consolidative radiotherapy after a full course of R-CHOP compared with R-CHOP alone in Stage I-II diffuse large B-cell lymphoma (KROG 17-02)

We compared treatment outcomes between rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy alone with R-CHOP followed by consolidative radiation therapy (RT) in diffuse large B-cell lymphoma (DLBCL). We analyzed 404 patients with Stage I-II DLBCL who received six to eight cycles of R-CHOP and achieved a good response after a full course of chemotherapy. Propensity-score matching was used to assess the role of consolidative RT. The R-CHOP alone group (n = 184) was matched in a 1:2 ratio with the R-CHOP plus RT group (n = 92). Twenty-four (13.0%) of 184 patients receiving R-CHOP alone and 8 (8.7%) of 92 patients receiving R-CHOP plus RT had bulky diseases (>7.5 cm). A Deauville score of 1-2 was achieved for 159 (86.4%) of 184 patients receiving R-CHOP alone and 84 (91.3%) of 92 patients receiving R-CHOP plus RT. After a median follow-up time of 42 months, the recurrence-free survival (RFS) rate (86.7% vs 93.0%, P = 0.464) and overall survival rate (88.3% vs 95.1%, P = 0.295) at 5 years did not differ significantly between the R-CHOP alone and R-CHOP plus RT arms. In the additional multivariate analyses, large tumor size (>7.5 cm) was significantly associated with decreased RFS (hazard ratio, 2.368 and confidence interval, 1.837-6.697; P = 0.048). Consolidative radiation was not a significant factor for RFS (P = 0.563). Tumor size was a significant factor for RFS in the rituximab era. The outcome of omitting consolidative RT for good responders after six to eight cycles of R-CHOP chemotherapy was acceptable in early-stage DLBCL without a bulky disease.

The prognostic value of PET/CT evaluation with Deauville score on the recurrence and survival in diffuse large B-cell lymphoma: a multi-institutional study of KROG 17-02

The Korean Radiation Oncology Group (KROG) assessed the value of Deauville score (DS) on ¹⁸F-fluorodeoxyglucose Positron emission tomography-computed tomography (FDG PET/CT) as a predictor of recurrence and survival after rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy in diffuse large B-cell lymphoma (DLBCL). A total of 512 patients with stage I-III DLBCL who received six cycles of R-CHOP with or without radiation therapy (RT) and obtained treatment responses according to PET-CT imagings after R-CHOP ± RT were included. Patients were sorted into two arms; DS 4-5 arm (n = 24) was matched at a 1:2 ratio with DS 1-3 arm (n = 48) using propensity score matching method. After a median follow-up time of 37.2 months, the recurrence-free survival rate (86.6% vs. 66.8%, P = 0.041) and overall survival rate (86.9% vs. 62.2%, P = 0.009) at 5 years were significantly different between the DS 1-3 and DS 4-5 arms. DS 4-5 arm showed higher 5-years locoregional recurrence-free survival (88.8% vs. 74.3%, P = 0.155) and distant failure-free survival (91.1% vs. 84.3%, P = 0.333) than DS 1-3 arm. In the multivariate analysis, DS was still a significant factor for recurrence-free survival [hazard ratio (HR), 3.840 and confidence interval (CI), 1.068-13.806; P = 0.039] and overall survival rates (HR 4.453 and CI 1.274-15.562; P = 0.019). This study showed and validated that Deauville score of 4-5 of PET-CT imaging taken after full-course of R-CHOP chemotherapy with or without RT could predict recurrence-free survival and overall survival in DLBCL patients.

Diabetes mellitus is a predictive factor for radiation pneumonitis after thoracic radiotherapy in patients with lung cancer

Purpose

We evaluated the effects of diabetes mellitus (DM) and DM-related serologic factors (HbA1c and fasting glucose) on the development of radiation pneumonitis in patients with lung cancer.

Methods

We retrospectively analyzed the clinical data of 123 patients with lung cancer treated with radiotherapy. Radiation pneumonitis was scored according to the toxicity criteria of the Radiation Therapy Oncology Group. We used binary logistic regression analysis to find significant predictive factors for the development of grade ≥3 radiation pneumonitis.

Results

On univariable analysis, V20, mean lung dose, DM, HbA1c, and fasting glucose level were significantly associated with the development of grade ≥3 radiation pneumonitis. On multivariable analysis, V20, mean lung dose, DM, HbA1c, and fasting glucose level remained significant predictive factors for grade ≥3 radiation pneumonitis. The incidence of grade ≥3 radiation pneumonitis was 44.4% in patients with DM and 20.7% in patients without DM. The incidence of grade ≥3 radiation pneumonitis was 12.7% for HbA1c level ≤6.15% and 41.5% for HbA1c level >6.15%. The incidence of grade ≥3 radiation pneumonitis was 17.2% for fasting glucose level ≤121 mg/dL and 35.5% for fasting glucose level >121 mg/dL.

Conclusion

DM, HbA1c, and fasting glucose level are significant predictive factors for the development of grade ≥3 radiation pneumonitis in patients with lung cancer. Patients with DM, patients who have HbA1c >6.15%, and patients who have fasting glucose >121 mg/dL should be treated with greater caution.

Adjuvant Chemotherapy in Rectal Cancer Patients Treated With Preoperative Chemoradiation and Total Mesorectal Excision: A Multicenter and Retrospective Propensity-Score Matching Study

PURPOSE

The role of adjuvant chemotherapy after preoperative chemoradiation therapy (CRT) and curative surgery in rectal cancer has yet to be definitely determined. We performed a retrospective and multicenter study to evaluate whether adjuvant chemotherapy (AC) could reduce recurrence and improve survival in locally advanced rectal cancer.

METHODS AND MATERIALS

We analyzed data from 8 tertiary institutions for 1442 patients with rectal cancer who underwent preoperative CRT and total mesorectal excision. Patients were classified into 2 groups: the AC group (patients who received chemotherapy after surgery) and the observation group (those who did not receive chemotherapy after surgery). Propensity-score matching was used to assess the exact role of AC. The AC group was then subdivided to investigate the impact of adding oxaliplatin to 5-fluorouracil (5-FU). Group 1 was treated with 5-FU/folinic acid or capecitabine without oxaliplatin, and group 2 received 5-FU/folinic acid or capecitabine with oxaliplatin.

RESULTS

The 3-year relapse-free survival rates in the AC and observation groups were 85.9% and 84.3%, respectively (P = .532). The 3-year overall survival rates in the AC and observation groups were 94.9% and 89.9%, respectively (P = .123). The rates of locoregional recurrence (2.2% vs 3.2%, P = .294) and distant metastasis (12.4% vs 12.9%, P = .927) at 3 years were not significantly different between the two groups. The 3-year relapse-free survival rates of group 1 and group 2 were 71.5% and 74.8%, respectively (P = .426). The 3-year overall survival rates of group 1 and group 2 were 89.9% and 96.5%, respectively (P = .102).

CONCLUSIONS

This multicenter study found insufficient evidence to support the use of 5-FU-based AC after preoperative CRT and curative surgery in rectal cancer.

A probiotic combination attenuates experimental colitis through inhibition of innate cytokine production

Inflammatory bowel disease (IBD) is a severe immune cell-mediated syndrome characterised by extensive inflammatory and effector mucosal responses leading to tissue destruction in the colon and small intestine. The leading hypothesis is that dysbiosis of the gut flora causes an excessive immune response and inflammation in the gastrointestinal track. Lactic acid bacteria (LAB) can correct dysbiosis of the normal microbiota. In the current study, the therapeutic potential of seven LAB strains in combination to treat IBD was evaluated using experimental colitis model. This LAB cocktail, designated GI7, includes four strains of Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactococcus lactis, two strains of Bifidobacterium bifidum, Bifidobacterium breve, and one strain of Streptococcus thermophilus. We confirmed that GI7 suppressed pro-inflammatory cytokines in Raw264.7 macrophages. When dextran sulphate sodium-induced colitic mice were treated with GI7, their symptoms of colitis, as assessed by body weight, colon length, myeloperoxidase activity, intestinal bleeding, and histological damage, were reduced compared to untreated mice. In addition, GI7 treatment significantly inhibited the production of innate pro-inflammatory cytokines during colitic progression. Therefore, we suggest that GI7, a combination of seven LAB, has a potential role in the treatment of IBD.

Comparison of contrast-enhanced CT angiography and gadolinium-enhanced MR angiography in the detection of subsegmental-sized pulmonary embolism: An experimental study in a pig model

Purpose: To compare contrast-enhanced CT angiography (CTA) and gadolinium-enhanced MR angiography (MRA) for the detection of subsegmental-sized pulmonary emboli in a pig model.

Material and Methods: In 5 anesthetized pigs, 3-mm diameter embolic materials made of Konjac, a semisolid food, were introduced through the internal jugular vein into pulmonary arteries. After embolization, CTA and MRA images were obtained. Respiration was suspended during CTA and MRA image acquisition. Two readers reviewed the CTA and MRA images to detect emboli. The pigs were sacrificed, and sliced specimens of inflated lung served as the gold standard.

Results: Thirty-six emboli were detected within peripheral arteries. The sensitivity (and 95% confidence intervals) of CTA for the two readers were 57% (39–74%) and 66% (48–81%), and 88% (69–98%) and 92% (74–94%) for MRA. The specificity of CTA was 95% (91–97%) and 98% (96–99%), and that of MRA was 85% (74–93%) and 90% (80–96%). Interobserver agreement was higher for MRA (kappa 0.898) than CTA (kappa 0.574).

Conclusion: For the detection of subsegmental pulmonary emboli, MRA was superior to CTA, with a higher sensitivity and interobserver agreement by demonstrating perfusion deficits.

Preoperative short- vs. long-course chemoradiotherapy with delayed surgery for locally advanced rectal cancer

PURPOSE

To compare the clinical outcomes between short-course chemoradiotherapy (CRT) and long-course CRT with delayed surgery in locally advanced rectal cancer patients.

RESULTS

From 2010 to 2015, 19 patients were treated with short-course CRT and 53 patients were treated with LCRT. The sphincter-saving rate (89.5% vs. 94.3%, short-course CRT vs. long-course CRT), pathologic complete remission (21.1% vs. 13.2%), downstaging (47.4% vs. 26.4%), and treatment complications including anastomotic site leakage, bowel adhesion, and hematologic toxicity associated with short-course CRT were not significantly different from those associated with long-course CRT. 2-year overall survival was 90.0% and 91.2% (p = 0.448), respectively.

METHODS AND MATERIALS

72 patients with stage cT3-4N0-2M0 rectal cancer participated in a multicenter study. Short-course CRT treatment was as follows: a total of 25 Gy of radiotherapy was delivered in 5 equal doses with intensity modulated radiation therapy. Chemotherapy was consisted of Leucovorin 400 mg/m² administered by bolus injection on day 1 and 5-Fluouracil 1200 mg/m² given by continuous infusion on days 1 and 2. An additional three cycles of chemotherapy were administered before the surgery. Long-course CRT treatment was as follows: a total of 50.4 Gy of radiotherapy was delivered in 28 equal doses. Chemotherapy consisted of a bolus injection of 5-Fluouracil + Leucovorin during the first and last week of radiotherapy. Surgery was performed 6-8 weeks after completion of radiotherapy in both groups.

CONCLUSIONS

Preoperative short-course CRT is an effective and safe modality. It is clinically comparable to long-course CRT in locally advanced rectal cancer.

Simple Prediction Model of Axillary Lymph Node Positivity After Analyzing Molecular and Clinical Factors in Early Breast Cancer

The aim of this study was to evaluate the association between pretreatment molecular and clinical factors and axillary lymph node metastases in early breast cancer. A total of 367 consecutive breast cancer patients with cT1-2NxM0 who underwent breast conserving surgery and axillary lymph node dissection followed by whole breast irradiation were enrolled. We evaluated the pathologic tumor and node status, tumor differentiation, calcification, and lymphovascular invasion, the status of estrogen receptor (ER), progesterone receptor (PR), epidermal growth factor receptor 1 (EGFR1), and human epidermal growth factor receptor 2 (HER2), the expression of E-cadherin, P53, and Ki-67 index. Totally, 108 (29.4%) of the 367 patients had positive axillary lymph nodes. An increased tumor size (P = 0.024), the presence of lymphovascular invasion (P < 0.001), and Ki-67 index of >20% (P = 0.038) were significantly associated with axillary lymph node metastases on the multivariate analysis. In our study, 86.2% of the patients with all the unfavorable factors had an involvement of axillary nodal metastases, and only 12.2% of the patients with all the favorable predictors had positive axillary nodes. The predictive power was significant on the receiver operating curve (P < 0.001). We found that several factors, such as tumor size, lymphovascular invasion, and the Ki-67 index, are independent factors that predict positive ALNM on multivariate analysis for the patients with cT1-2 breast cancer. Clinicians simply could predict the probability of ALNM after verifying the molecular and clinical factors in early breast cancer.

Predictors of Distant Metastasis after Radical Surgery Followed by Postoperative Radiotherapy with or without Chemotherapy for Oropharyngeal Cancer

Purpose

We investigated the prognostic factors for distant metastasis (DM) in patients with locally advanced oropharyngeal cancer (OPC) treated with surgery and adjuvant radiotherapy with or without concurrent chemotherapy.

Materials and Methods

Eighty-five patients treated between January 1995 and August 2014 were evaluated retrospectively. Data regarding the pathological tumour and nodal status, human papillomavirus (HPV) status, treatment characteristics, and pretreatment maximum standardized uptake value (SUVmax) of 18-fluoro-2-deoxyglucose positron emission tomography–computed tomography scan (¹⁸F-FDG PET-CT) were evaluated, and their influence on DM and survival outcomes were analyzed.

Results

Median follow-up period was 48.0 months. Recurrence was observed in 20 patients, including locoregional recurrence and DM. DM was observed in 13 patients. A multivariate analysis confirmed that the presence of lymphovascular invasion (p=0.031), lower neck lymph node (LN) involvement (p=0.006), SUVmax ≥ 9.7 (p=0.014), and tumour size ≥ 3 cm (p=0.037) significantly affected DM. HPV status was not associated with DM. Perineural invasion (p=0.048), lower neck LNinvolvement (p=0.008), SUVmax ≥ 9.7 (p=0.019), and tumour size ≥ 3 cm (p=0.033) were also significant factors for the DM-free survival rate.

Conclusion

Lower neck LN involvement, high SUVmax in pretreatment ¹⁸F-FDG PET-CT, and large tumour size were predictive factors for DM in patients of OPC.

Soft Tissue Necrosis in Head and Neck Cancer Patients After Transoral Robotic Surgery or Wide Excision With Primary Closure Followed by Radiation Therapy

Risk factors were evaluated for surgical bed soft tissue necrosis (STN) in head and neck cancer patients treated with postoperative radiation therapy (PORT) after transoral robotic surgery (TORS) or wide excision with primary closure. Sixty-seven patients were evaluated. STN was defined as ulceration and necrosis of the surgical bed or persistently unhealed high-grade acute mucositis with pain after PORT. The median RT dose of primary site was 63.6 Gy (range, 45-67.15 Gy) with 2 Gy/fx (range 1.8-2.2 Gy/fx). Total 41 patients (61.2%) were treated with concurrent chemoradiotherapy. The median follow-up period was 26 months. STN was diagnosed in 13 patients (19.4%). Most of the patients were treated with oral steroids, antibiotics, and analgesics and the lesions were eventually improved (median of 6 months after PORT). STN did not influence local control. A depth of invasion (DOI > 1.4 cm, odds ratio [OR] 14.04, p = 0.004) and maximum dose/fraction (CTVpmax/fx > 2.3 Gy, OR 6.344, p = 0.043) and grade 3 acute mucositis (OR 6.090, p = 0.054) were related to STN. The 12 (23.5%) of 51 oropharyngeal cancer patients presented STN, and the risk factors were DOI > 1.2 cm (OR 21.499, P = 0.005), CTVpmax/fx > 2.3 Gy (OR 12.972, P = 0.021) and grade 3 acute mucositis (OR 10.537, P = 0.052). Patients treated with TORS or WE with primary closure followed by PORT had a high risk of surgical bed STN. STN risk factors included DOI (>1.2-1.4 cm) and CTVpmax/fx (>2.3 Gy). Radiation therapy after TORS must be carefully designed to prevent STN.

Analysis of Geometric Shifts and Proper Setup-Margin in Prostate Cancer Patients Treated With Pelvic Intensity-Modulated Radiotherapy Using Endorectal Ballooning and Daily Enema for Prostate Immobilization

We evaluate geometric shifts of daily setup for evaluating the appropriateness of treatment and determining proper margins for the planning target volume (PTV) in prostate cancer patients.We analyzed 1200 sets of pretreatment megavoltage-CT scans that were acquired from 40 patients with intermediate to high-risk prostate cancer. They received whole pelvic intensity-modulated radiotherapy (IMRT). They underwent daily endorectal ballooning and enema to limit intrapelvic organ movement. The mean and standard deviation (SD) of daily translational shifts in right-to-left (X), anterior-to-posterior (Y), and superior-to-inferior (Z) were evaluated for systemic and random error.The mean ± SD of systemic error (Σ) in X, Y, Z, and roll was 2.21 ± 3.42 mm, -0.67 ± 2.27 mm, 1.05 ± 2.87 mm, and -0.43 ± 0.89°, respectively. The mean ± SD of random error (δ) was 1.95 ± 1.60 mm in X, 1.02 ± 0.50 mm in Y, 1.01 ± 0.48 mm in Z, and 0.37 ± 0.15° in roll. The calculated proper PTV margins that cover >95% of the target on average were 8.20 (X), 5.25 (Y), and 6.45 (Z) mm. Mean systemic geometrical shifts of IMRT were not statistically different in all transitional and three-dimensional shifts from early to late weeks. There was no grade 3 or higher gastrointestinal or genitourianry toxicity.The whole pelvic IMRT technique is a feasible and effective modality that limits intrapelvic organ motion and reduces setup uncertainties. Proper margins for the PTV can be determined by using geometric shifts data.

A Dosimetric Comparative Analysis of TomoDirect and Three-Dimensional Conformal Radiotherapy in Early Breast Cancer

PURPOSE

The purpose of this study is to compare dosimetric parameters of intensity-modulated mode of TomoDirect and three-dimensional conformal radiotherapy (3D-CRT) in patients with early breast cancer.

METHODS

TomoDirect and 3D-CRT planning were carried out for 26 patients with early breast cancer who had received breast-conserving surgery. A total of 50.4 Gy in 28 fractions were prescribed to the planning target volume. The organs at risk (OAR) such as lung and heart were contoured. Planning target volume (PTV) dose coverage, radiation conformity index (RCI), radical dose homogeneity index (rDHI), and irradiation dose of organs at risk were compared between TomoDirect and 3D-CRT planning.

RESULTS

The mean PTV dose (51.65±0.37 Gy) and V47.8 (100%) in TomoDirect were significantly higher than the mean PTV dose (50.88±0.65 Gy) and V47.8 (89.23%±0.06%) in 3D-CRT (all, p<0.001). The RCI value in TomoDirect was significantly better than that in 3D-CRT (1.00 vs. 1.13, p<0.001). However, the rDHI value in TomoDirect was not significantly better than that in 3D-CRT (0.72 vs. 0.67, p=0.056). The mean lung dose and V10, V20, V30, and V40 values of ipsilateral lung in TomoDirect were significantly lower than those in 3D-CRT (all, p<0.05). There is no significant difference in the V10, V20, V30, and V40 values of heart between TomoDirect and 3D-CRT. And the mean dose for heart in TomoDirect was marginally lower than that in 3D-CRT (1.05 Gy vs. 1.62 Gy, p=0.085). The mean dose for left anterior descending coronary artery in left breast cancer was significantly lower in TomoDirect than in 3D-CRT (7.2 Gy vs. 12.1 Gy, p<0.001).

CONCLUSION

Compared to 3D-CRT, TomoDirect could result in favorable target coverage while reducing the irradiation dose of the ipsilateral lung for patients with early breast cancer.

Evaluation of the Flash effect in breast irradiation using TomoDirect: an investigational study

Flash is a specified function in TomoDirect that enables beam expansion by opening additional leaves to the target. This study assessed the theoretical dose distribution resulting from Flash in breast irradiation using TomoDirect. A cylindrical phantom that enabled dose distribution of the breast was used for verifying the effect of planning target volume (PTV) contouring and Flash. A total of 18 Gy in 10 fractions were prescribed to the PTV. Five PTVs were then created by Contracting this contour by 0, 1, 2, 3, 4 and 5 mm, giving PTV-x. Flash ±x is defined by opening x (number) of the leaves. The Flash effect in the air was compared with each set-up error of 5, 10 and 15 mm, respectively. The minimum PTV dose from PTV-1 to PTV-3 increased from 13.88 Gy to 15.86 Gy. In contrast, Dmin in PTV-4 and PTV-5 was 17.80 Gy in 98.88% of the prescription dose. Without Flash, when 5-, 10- and 15-mm set-up errors applied in the PTV, relative doses of 87.88, 23.73 and 7.94% were observed, respectively. However, in Flash 3, which was equal to the usual air margin of 1.875 cm, a relative dose of 104.24% ± 0.30% was observed, irrespective of set-up errors (5 mm to 15 mm). Flash opening is useful for countervailing set-up errors in breast cancer patients who receive breast irradiation with TomoDirect.

Setup Error and Effectiveness of Weekly Image-Guided Radiation Therapy of TomoDirect for Early Breast Cancer

PURPOSE

This study investigated setup error and effectiveness of weekly image-guided radiotherapy (IGRT) of TomoDirect for early breast cancer.

MATERIALS AND METHODS

One hundred and fifty-one breasts of 147 consecutive patients who underwent breast conserving surgery followed by whole breast irradiation using TomoDirect in 2012 and 2013 were evaluated. All patients received weekly IGRT. The weekly setup errors from simulation to each treatment in reference to chest wall and surgical clips were measured. Random, systemic, and 3-dimensional setup errors were assessed. Extensive setup error was defined as 5 mm above the margin in any directions.

RESULTS

All mean errors were within 3 mm of all directions. The mean angle of gantry shifts was 0.6°. The mean value of absolute 3-dimensional setup error was 4.67 mm. In multivariate analysis, breast size (odds ratio, 2.82; 95% confidence interval, 1.00 to 7.90) was a significant factor for extensive error. The largest significant deviation of setup error was observed in the first week of radiotherapy (p < 0.001) and the deviations gradually decreased with time. The deviation of setup error was 5.68 mm in the first week and within 5 mm after the second week.

CONCLUSION

In this study, there was a significant association between breast size and significant setup error in breast cancer patients who received TomoDirect. The largest deviation occurred in the first week of treatment. Therefore, patients with large breasts should be closely observed on every fraction and fastidious attention is required in the first fraction of IGRT.

Postoperative Radiotherapy Alone Versus Chemoradiotherapy in Stage I-II Endometrial Carcinoma: An Investigational and Propensity Score Matching Analysis

Purpose

The purpose of this study was to compare the results of postoperative adjuvant radiotherapy (RT) and concurrent chemoradiotherapy (CRT) in stage I-II endometrial carcinoma.

Materials and Methods

We analyzed a total of 64 patients with surgically staged I-II endometrial carcinoma who were treated with postoperative adjuvant RT or concurrent CRT between March 1999 and July 2013. Thirty-two patients who received postoperative RT alone were matched with those who received postoperative CRT (n=32) in accordance to age, stage, and tumor histology. Overall survival and relapse-free survival, as well as toxicity of the RT and CRT arms were evaluated and compared.

Results

The 5-year overall survival rate was 90.0% for the RT arm and 91.6% for the CRT arm. There was no significant difference in overall survival between the two treatment arms (p=0.798). The 5-year relapse-free survival rate was 87.2% in the RT arm and 88.0% in the CRT arm. Again, no significant difference in relapse-free survival was seen between the two arms (p=0.913). In a multivariate analysis, tumor histology was an independent prognostic factor for relapse-free survival (hazard ratio, 3.67; 95% of CI, 2.34 to 7.65; p=0.045). Acute grade 3 or 4 hematologic toxicities in the CRT arm were significantly higher than in the RT alone arm (6.2% vs. 31.2%, p=0.010).

Conclusion

Adjuvant pelvic concurrent chemoradioherapy did not show superior results in overall survival and relapse-free survival compared to RT alone in stage I-II endometrial carcinoma.

A prospective cohort study on postoperative radiotherapy with TomoDirect using simultaneous integrated boost technique in early breast cancer

PURPOSE

To evaluate the technical feasibility and toxicity of TomoDirect in breast cancer patients who received radiotherapy after breast-conserving surgery.

METHODS

155 consecutive patients with breast carcinoma in situ or T1-2 breast cancer with negative lymph node received breast irradiation with TomoDirect using simultaneous integrated boost technique in the prospective cohort study. A radiation dose of 50.4 Gy and 57.4 Gy in 28 fractions was prescribed to the ipsilateral breast and tumor bed, respectively. Dosimetric parameters of target and organ at risk and acute complication were assessed prospectively.

RESULTS

The mean dose for the tumor bed is 58.90 Gy. The mean values of V54.53Gy (95% of the prescribed dose), V63.14Gy (110% of the prescribed dose), and V66.01Gy (115% of the prescribed dose) were 99.97%, 1.26%, and 0%, respectively. The mean value of radiation conformality index was 1.01. The mean value of radical dose homogeneity index was 0.89. The average dose irradiated to the ipsilateral lung, heart, and contralateral breast was 4.72 Gy, 1.09 Gy, and 0.19 Gy, respectively. The most common toxicity was dermatitis. During breast irradiation, grade 2 and 3 dermatitis occurred in 41 (26.5%) and 6 (3.9%) of the 155 patients, respectively. Two patients had arm lymphedema during breast irradiation. Two patients had grade 2 pneumonitis 1 month after breast irradiation.

CONCLUSIONS

Radiotherapy using TomoDirect in early breast cancer patients showed acceptable toxicities and optimal results in terms of target coverage and organ at risk sparing.

Outcome of postoperative radiotherapy following radical prostatectomy: a single institutional experience

Purpose

This single institutional study is aimed to observe the outcome of patients who received postoperative radiotherapy after radical prostatectomy.

Materials and Methods

A total of 59 men with histologically identified prostate adenocarcinoma who had received postoperative radiation after radical prostatectomy from August 2005 to July 2011 in Seoul St. Mary's Hospital of the Catholic University of Korea, was included. They received 45-50 Gy to the pelvis and boost on the prostate bed was given up to total dose of 63-72 Gy (median, 64.8 Gy) in conventional fractionation. The proportion of patients given hormonal therapy and the pattern in which it was given were analyzed. Primary endpoint was biochemical relapse-free survival (bRFS) after radiotherapy completion. Secondary endpoint was overall survival (OS). Biochemical relapse was defined as a prostate-specific antigen level above 0.2 ng/mL.

Results

After median follow-up of 53 months (range, 0 to 104 months), the 5-year bRFS of all patients was estimated 80.4%. The 5-year OS was estimated 96.6%. Patients who were given androgen deprivation therapy had a 5-year bRFS of 95.1% while the ones who were not given any had that of 40.0% (p < 0.01). However, the statistical significance in survival difference did not persist in multivariate analysis. The 3-year actuarial grade 3 chronic toxicity was 1.7% and no grade 3 acute toxicity was observed.

Conclusion

The biochemical and toxicity outcome of post-radical prostatectomy radiotherapy in our institution is favorable and comparable to those of other studies.

BAX inhibitor-1-associated V-ATPase glycosylation enhances collagen degradation in pulmonary fibrosis

Endoplasmic reticulum (ER) stress is considered one of the pathological mechanisms of idiopathic pulmonary fibrosis (IPF). Therefore, we examined whether an ER stress regulator, Bax inhibitor-1 (BI-1), regulates collagen accumulation, which is both a marker of fibrosis and a pathological mechanism of fibrosis. The presence of BI-1 inhibited the transforming growth factor-β1-induced epithelial-mesenchymal transition of epithelial pulmonary cells and bleomycin-induced pulmonary fibrosis in a mouse model by enhancing collagen degradation, most likely by enhanced activation of the lysosomal V-ATPase through glycosylation. We also found a correlation between post-translational glycosylation of the V-ATPase and its associated chaperone, calnexin, in BI-1-overexpressing cells. BI-1-induced degradation of collagen through lysosomal V-ATPase glycosylation and the involvement of calnexin were confirmed in a bleomycin-induced fibrosis mouse model. These results highlight the regulatory role of BI-1 in IPF and reveal for the first time the role of lysosomal V-ATPase glycosylation in IPF.

Dosimetric evaluation of Tomotherapy and four-box field conformal radiotherapy in locally advanced rectal cancer

Purpose

To report the results of dosimetric comparison between intensity-modulated radiotherapy (IMRT) using Tomotherapy and four-box field conformal radiotherapy (CRT) for pelvic irradiation of locally advanced rectal cancer.

Materials and Methods

Twelve patients with locally advanced rectal cancer who received a short course preoperative chemoradiotherapy (25 Gy in 5 fractions) on the pelvis using Tomotherapy, between July 2010 and December 2010, were selected. Using their simulation computed tomography scans, Tomotherapy and four-box field CRT plans with the same dose schedule were evaluated, and dosimetric parameters of the two plans were compared. For the comparison of target coverage, we analyzed the mean dose, V_{n Gy}, D_min, D_max, radical dose homogeneity index (rDHI), and radiation conformity index (RCI). For the comparison of organs at risk (OAR), we analyzed the mean dose.

Results

Tomotherapy showed a significantly higher mean target dose than four-box field CRT (p = 0.001). But, V_{26.25 Gy} and V_{27.5 Gy}were not significantly different between the two modalities. Tomotherapy showed higher D_max and lower D_min. The Tomotherapy plan had a lower rDHI than four-box field CRT (p = 0.000). Tomotherapy showed better RCI than four-box field CRT (p = 0.007). For OAR, the mean irradiated dose was significantly lower in Tomotherapy than four-box field CRT.

Conclusion

In locally advanced rectal cancer, Tomotherapy delivers a higher conformal radiation dose to the target and reduces the irradiated dose to OAR than four-box field CRT.

Tumor bed volumetric changes during breast irradiation for the patients with breast cancer

Purpose

The aim of this study was to evaluate changes in breast tumor bed volume during whole breast irradiation (WBI).

Materials and Methods

From September 2011 to November 2012, thirty patients who underwent breast-conserving surgery (BCS) followed by WBI using computed tomography (CT) simulation were enrolled. Simulation CT scans were performed before WBI (CT1) and five weeks after the breast irradiation (CT2). The tumor bed was contoured based on surgical clips, seroma, and postoperative change. We retrospectively analyzed the factors associated with tumor bed volumetric change.

Results

The median tumor bed volume on CT1 and CT2 was 29.72 and 28.6 mL, respectively. The tumor bed volume increased in 9 of 30 patients (30%) and decreased in 21 of 30 patients (70%). The median percent change in tumor bed volume between initial and boost CT was -5%. Seroma status (p = 0.010) was a significant factor in tumor bed volume reduction of 5% or greater. However, patient age, body mass index, palpability, T stage, axillary lymph node dissection, and tumor location were not significant factors for tumor bed volumetric change.

Conclusion

In this study, volumetric change of tumor bed cavity was frequent. Patients with seroma after BCS had a significant volume reduction of 5% or greater in tumor bed during breast irradiation. Thus, resimulation using CT is indicated for exquisite boost treatment in breast cancer patients with seroma after surgery.

A novel disposable, transnasal esophagoscope: a pilot trial of feasibility, safety, and tolerance

A novel disposable transnasal esophagoscope, the E.G. Scan (IntroMedic Co. Ltd., Seoul, Korea), was developed for the evaluation of esophageal diseases while eliminating the inconvenience associated with sterilization, portability, patient monitoring, complications, and the economic burden of sedation. The feasibility, safety, and tolerability of the first version of the E.G. Scan was evaluated in this pilot study. Nasal esophagoscopy was performed successfully in 46 patients with known or suspected esophageal diseases. At least 50% of the Z-line was visualized by the E.G. Scan in 38 (82.6%) of 46 patients. Abnormalities were identified in 27 patients: erosive esophagitis (n=18), Barrett's esophagus (n=1), esophageal varices (n=7), and esophageal candidiasis (n=1). Nasal pain was absent or mild in most patients, and adverse events were not observed. Further technical improvement of the E.G. Scan would increase the diagnostic usefulness in future clinical practice.

Antiapoptotic effect of found in inflammatory zone (FIZZ)1 on mouse lung fibroblasts

Myofibroblasts play an essential role in the abnormal deposition of extracellular matrix in pulmonary fibrosis. The presence or prolonged survival of these cells may be a key factor in the pathogenesis of progressive pulmonary fibrosis. Found in inflammatory zone (FIZZ)1 can induce myofibroblast differentiation and has an antiapoptotic effect on embryonic lung explant cultures. In this study, we investigated whether FIZZ1 also has an antiapoptotic effect on mouse lung fibroblasts (MLFs). Cells were treated with FIZZ1 for 24 h and then apoptosis was induced by TNFalpha in the presence of cycloheximide (CHX). FIZZ1 exhibited an antiapoptotic effect in MLFs, as assessed by flow cytometric analysis and TUNEL staining. Moreover, the cell number was higher in the FIZZ1-treated group relative to the non-treated control group after treatment with TNFalpha and CHX. FIZZ1 treatment also inhibited the apoptotic agent-induced activities of caspase-3 and caspase-8. Examination of potential signalling pathways revealed that FIZZ1 induced rapid phosphorylation of ERK-1/2, while PD98059, a MEK/ERK inhibitor, markedly induced activation of caspase-3. This anti-apoptotic effect of FIZZ1 was associated with induction of myofibroblast differentiation in response to FIZZ1 stimulation. Taken together, these findings suggest that FIZZ1 is involved in pulmonary fibrosis through both induction of myofibroblast differentiation and increased or prolonged survival of myofibroblasts. This effect of FIZZ1 was mediated by inhibition of caspase-3 and -8, with involvement of the ERK pathway.

Pulmonary TB and NTM lung disease: comparison of characteristics in patients with AFB smear-positive sputum

OBJECTIVE

To compare the clinical and radiographic features of pulmonary tuberculosis (PTB) and non-tuberculous mycobacteria (NTM) lung disease in patients with acid-fast bacilli (AFB) positive sputum specimens.

DESIGN

The initial clinical and radiographic features of 229 PTB patients were compared with those of 70 patients with NTM lung disease. The most commonly involved organisms in the NTM lung disease cases were Mycobacterium avium complex (n = 38, 54%) and M. abscessus (n = 26, 37%).

RESULTS

Clinical and radiographic findings that were more common in patients with NTM lung disease than in PTB patients were: older age (P < 0.001), non-smoker (P < 0.001), history of previous TB treatment (P < 0.001), absence of pleural effusion (P = 0.017), involvement of middle and/or lower lung zones (P = 0.007), and bilateral disease (P = 0.005). Multivariate analysis showed that older age (> or = 40 years), non-smoker, previous TB treatment, absence of pleural effusion and involvement of middle and/or lower lung zones were significant independent predictors for NTM lung disease.

CONCLUSIONS

There is considerable overlap in the clinical and radiographic appearances of PTB and NTM lung disease. The isolation and identification of causative organisms are mandatory for a correct diagnosis in patients with AFB-positive sputum specimens.

Posterior mediastinal paraganglioma with bilateral adrenal pheochromocytoma

Paraganglioma and adrenal pheochromocytoma are tumors of common origin arising from chromaffin cells. However, it is extremely rare to find mediastinal paraganglioma simultaneously with bilateral adrenal pheochromocytoma. We report a 53-year-old man who was diagnosed with posterior mediastinal paraganglioma and bilateral adrenal pheochromocytoma and who underwent successful excision of the posterior mediastinal mass and bilateral total adrenalectomy.

Comparison of contrast-enhanced ct angiography and gadolinium-enhanced MR angiography in the detection of subsegmental-sized pulmonary embolism. An experimental study in a pig model

PURPOSE

To compare contrast-enhanced CT angiography (CTA) and gadolinium-enhanced MR angiography (MRA) for the detection of subsegmental-sized pulmonary emboli in a pig model.

MATERIAL AND METHODS

In 5 anesthetized pigs, 3-mm diameter embolic materials made of Konjac, a semisolid food, were introduced through the internal jugular vein into pulmonary arteries. After embolization, CTA and MRA images were obtained. Respiration was suspended during CTA and MRA image acquisition. Two readers reviewed the CTA and MRA images to detect emboli. The pigs were sacrificed, and sliced specimens of inflated lung served as the gold standard.

RESULTS

Thirty-six emboli were detected within peripheral arteries. The sensitivity (and 95% confidence intervals) of CTA for the two readers were 57% (39-74%) and 66% (48-81%), and 88% (69-98%) and 92% (74-94%) for MRA. The specificity of CTA was 95% (91-97%) and 98% (96-99%), and that of MRA was 85% (74-93%) and 90% (80-96%). Interobserver agreement was higher for MRA (kappa 0.898) than CTA (kappa 0.574).

CONCLUSION

For the detection of subsegmental pulmonary emboli, MRA was superior to CTA, with a higher sensitivity and interobserver agreement by demonstrating perfusion deficits.

Volatile N-nitrosamine inhibition after intake Korean green tea and Maesil (Prunus mume SIEB. et ZACC.) extracts with an amine-rich diet in subjects ingesting nitrate

The formation of carcinogenic nitrosamines under simulated gastric conditions was studied during the incubation of amine rich food and nitrate, and its possible inhibition by adding kumquat, sweet orange, strawberry, garlic, kale juices, Maesil (Prunus mume) and green tea extracts. The strawberry, kale juices, Maesil and green tea extracts were equally effective in reducing the formation of N-nitrosodimethylamine (NDMA). The fruits of P. mume SIEB. et ZACC. (Korean name, Maesil) have been used as a traditional drug and health food in Korea. During four weeks of test (designated EW1, EW2, EW3 and EW4; experiment week 1, 2, 3 and 4 diets) volunteers consumed a diet of low nitrate and amine (EW1) and consumed a fish meal rich in amines as nitrosatable precursors in combination with intake of nitrate-containing drinking water without (EW2) or with Maesil and green tea extracts (EW3 and EW4, respectively). The intake of nitrate-containing drinking water (340 mg nitrate/100 ml) resulted in a significant rise in mean salivary nitrate and nitrite concentrations and in mean urinary nitrate levels. Mean urinary nitrate was increased to 455.0+/-66.2, 334.6+/-67.8 and 333.4+/-50.7 mg/18 h after the nitrate intake of EW2, EW3 and EW4, respectively. Significant increases in urinary dimethylamine and trimethylamine levels were observed in consumption of diets (EW2, EW3, and EW4) rich in amine and nitrate. Maesil and green tea extract in EW3 and EW4 enhanced the increase of urinary dimethylamine and trimethylamine levels. Urinary excretion of N-nitrosodimethylamine in consumption of diet rich in nitrate and amine (EW2) increased to 6504.4+/-2638.7 ng/18 h from 257.0+/-112.0 ng/18 h of low nitrate and amine diet (EW1). Korean green tea and Maesil extracts in nitrate and amine rich diet reduced the excretion of N-nitrosodimethylamine to 249.7+/-90.6 and 752.7+/-595.3 ng/18 h, respectively, compared with 6504.4+/-2638.7 ng /18 h after ingestion of TD1 diet.

Utility of thyroid transcription factor-1 and cytokeratin 7 and 20 immunostaining in the identification of origin in malignant effusions

OBJECTIVE

To estimate the utility of thyroid transcription factor-1 (TTF-1) and the combined cytokeratin 7 (CK7) and 20 (CK20) immunoprofile as a marker for identifying the primary site of metastatic adenocarcinoma in effusions of the serous cavity.

STUDY DESIGN

Formalin-fixed, paraffin-embedded cell block specimens of pleural and peritonealfluid diagnosed as metastatic adenocarcinomas with known sites of origin were used for TTF-1, CK7 and CK20 immunohistochemistry. The primary sites of these cases were lung (16 cases), ovary (15), stomach (9), colon (8) and breast (8) and were confirmed by radiologic and/or histologic evaluation.

RESULTS

The lung adenocarcinomas showed TTF-1 positivity in 81% (13/16) of cases. All nonpulmonary adenocarcinomas lacked TTF-1 staining. The CK7-/CK20+ immunophenotype was seen in 63% of colonic adenocarcinomas and not seen in lung, ovary, stomach or breast adenocarcinomas. The CK7+/CK20- immunophenotype was seen in 100%, 88% and 87% of cases that originated in the lung, breast and ovary, respectively.

CONCLUSION

TTF-7 immunostaining is useful in the differentiation between pulmonary and nonpulmonary origin of adenocarcinomas in malignant effusions. The combination of CK7-/CK20+ immunostaining is useful in identifying colon adenocarcinomas.

Intrathoracic malignant peripheral nerve sheath tumor in von Recklinghausen's disease

Malignant peripheral nerve sheath tumor (MPNST) is defined as any malignant tumor arising from or differentiating toward the cells of the peripheral nerve sheath. MPNST accounts for about 5-10% of all soft tissue tumors and is often associated with neurofibromatosis type I (NF-1, von Recklinghausen's disease). It is one of the malignant tumors associated with von Recklinghausen's disease. Its common site is the lower and upper extremities, trunk, head and neck. But intrathoracic manifestations are very rare. We report a case of a 40 year-old man with multiple neurofibromatosis who was presented with an intrathoracic malignant peripheral nerve sheath tumor.

A case of bronchiolitis obliterans organizing pneumonia with renal dysfunction after renal transplantation

A 35-year-old male renal transplant patient was admitted with 3-week history of cough and myalgia after a 3-month post-transplantation. The patient's posttransplant course was uncomplicated and had no rejection. But on admission, the serum creatinine was 3.0 mg/dl and high-resolution computed tomography (HRCT) showed bilateral patchy densities and peripheral consolidations. Renal biopsy revealed mononuclear cell infiltration and non-specific tubular injury without evidence of rejection. An open lung biopsy was performed which showed multiple fibroblast plugs filling airspaces that were typical pathologic features of bronchiolitis obliterans with organizing pneumonia (BOOP). After prednisone therapy, the patient's pulmonary symptoms and radiographic findings rapidly recovered and serum creatinine also decreased from 3.0 to 2.1 mg/dl. Although the cause of renal dysfunction was not elucidated, we herein report a rare case of BOOP with renal dysfunction after renal transplantation.

Atypical pulmonary metastases: spectrum of radiologic findings

Typical radiologic findings of a pulmonary metastasis include multiple round variable-sized nodules and diffuse thickening of interstitium. In daily practice, however, atypical radiologic features of metastases are often encountered that make distinction of metastases from other nonmalignant pulmonary diseases difficult. A detailed knowledge of the atypical radiologic features of a pulmonary metastasis with a good understanding of the histopathologic background is essential for correct diagnosis. Squamous cell carcinoma is regarded as the most common cell type of a cavitating metastasis, but metastatic nodules from adenocarcinomas and sarcomas also cavitate occasionally. Calcification can occur in a metastatic sarcoma or adenocarcinoma, which makes differentiation from a benign granuloma or hamartoma difficult. Peritumoral hemorrhage results in areas of nodular attenuation surrounded by a halo of ground-glass opacity. Pneumothorax commonly occurs in metastases from an osteosarcoma. Air-space consolidation is often seen in cases of metastases from gastrointestinal tract malignancies. Even though tumor emboli in pulmonary arteries can be seen at computed tomography, diagnosis is difficult because they are located in small or medium arteries. A common radiologic appearance of an endobronchial metastasis is an atelectasis. In cases of an endobronchial or a solitary pulmonary metastasis, differentiation between bronchogenic carcinoma and metastasis is difficult. Dilated vascular structures within the mass can be seen in metastatic sarcomas. A sterilized metastasis after chemotherapy is radiologically indistinguishable from a residual viable tumor. Benign tumors such as uterine leiomyomas and giant cell tumors of the bone rarely metastasize to the lung.

Coadministration of angiopoietin-1 and vascular endothelial growth factor enhances collateral vascularization

Using growth factors to induce vasculogenesis is a promising approach in the treatment of ischemic legs and myocardium. Because the vasculogenesis requires a cascade of growth factors, their receptors, and intracellular signals, such therapies may require the application of more than a single growth factor. We examined the effect of 2 endothelial cell-specific growth factors, angiopoietin-1 (Ang1) and vascular endothelial growth factor (VEGF), on primary cultured porcine coronary artery endothelial cells. VEGF, but not Ang1, increased DNA synthesis and cell number. Ang1 or VEGF induced migration and sprouting activity, increased plasmin and matrix metalloproteinase-2 secretion, and decreased tissue inhibitors of metalloproteinase type 2 secretion. A combination of the submaximal doses of Ang1 and VEGF enhanced these effects and was more potent than the maximal dose of either alone. In a rabbit ischemic hindlimb model, a combination of Ang1 and VEGF gene delivery produced an enhanced effect on resting and maximal blood flow and capillary formation that was greater than that of either factor alone. Angiographic analyses revealed that larger blood vessels were formed after gene delivery of Ang1 or Ang1 plus VEGF than after VEGF gene delivery. These results suggest that combined treatment of Ang1 and VEGF could be used to produce therapeutic vascularization.

Pale bodies in hepatocellular carcinoma

Histochemical, immunohistochemical and ultrastructural studies were performed on cases of hepatocellular carcinoma (HCC) with pale bodies (PB). HCC containing PBs was observed in 3 (5.5%) of 55 consecutively resected HCC cases. Histologically, a large number of hepatocytes displayed pale or eosinophilic staining of the cytoplasm, resulting in ground-glass appearance. They were aggregated in nodular pattern, or diffusely intermixed with other malignant hepatocytes. PBs were negative for periodic-acid Schiff and Masson's trichrome staining. The inclusions showed a strong positive reaction for fibrinogen and some of them were weakly positive for albumin but negative for hepatitis B surface antigen, hepatitis B core antigen, alpha-fetoprotein and alpha-1-antitrypsin. Ultrastructurally, PBs were membrane-bound and contained granular materials of moderate electron density, and were closely related to dilated rough endoplasmic reticulum. These findings support that PBs are secretory fibrinogen accumulated in cystic ER and that such intracellular accumulation possibly reflects a defective transport of fibrinogen.

Evaluation of tracheobronchial diseases: comparison of different imaging techniques

OBJECTIVE

To compare the clinical utility of the different imaging techniques used for the evaluation of tracheobronchial diseases.

MATERIALS AND METHODS

Forty-one patients with tracheobronchial diseases [tuberculosis (n = 18), bronchogenic carcinoma (n = 10), congenital abnormality (n = 3), post-operative stenosis (n = 2), and others (n = 8)] underwent chest radiography and spiral CT. Two sets of scan data were obtained: one from routine thick-section axial images and the other from thin-section axial images. Multiplanar reconstruction (MPR) and shaded surface display (SSD) images were obtained from thin-section data. Applying a 5-point scale, two observers compared chest radiography, routine CT, thin-section spiral CT, MPR and SSD imaging with regard to the detection, localization, extent, and characterization of a lesion, information on its relationship with adjacent structures, and overall information.

RESULTS

SSD images were the most informative with regard to the detection (3.95+/-0.31), localization (3.95+/-0.22) and extent of a lesion (3.85+/-0.42), and overall information (3.83+/-0.44), while thin-section spiral CT scans provided most information regarding its relationship with adjacent structures (3.56+/-0.50) and characterization of the lesion (3.51+/-0.61).

CONCLUSION

SSD images and thin-section spiral CT scans can provide valuable information for the evaluation of tracheobronchial disease.

Propofol attenuates ischemia-reperfusion injury in the isolated rat heart

The purpose of this study was to examine the direct effects of propofol on ischemia-reperfusion injury using an isolated Langendorff rat heart preparation. Hearts were perfused with Krebs-Henseleit (K-H) solution (control); intralipid; or 10, 30, and 100 microM propofol. Hearts were rendered globally ischemic for 25 min, then reperfusion was begun with K-H solution for 30 min. Treatment with 100 microM propofol delayed the onset of contracture during ischemia compared with control or intralipid treatments (6.4 +/- 2.1 vs 4.4 +/- 1.4 or 4.1 +/- 0.7 min, respectively; P < 0.05). During reperfusion, 100 microM propofol increased coronary flow and reduced lactate dehydrogenase release compared with control or intralipid treatments. After 30 min of reperfusion, left ventricular developed pressure (LVDP) returned to 55 and 76 mm Hg in the 30 and 100 microM propofol-treated groups, respectively, whereas LVDP was 39 mm Hg in the control group. The hearts treated with 100 microM propofol showed significantly lower left ventricular end-diastolic pressure compared with the control or intralipid groups 30 min after reperfusion (29 +/- 13 vs 48 +/- 5 or 48 +/- 11 mm Hg, respectively; P < 0.05). In histological evaluation, control and intralipid hearts had increased injury severity scores compared with hearts treated with 100 microM propofol (1.8 +/- 0.9 and 1.7 +/- 0.8 vs 1.0 +/- 0.7, respectively; P < 0.05). In conclusion, we suggest that propofol administered before and during global myocardial ischemia has cardioprotective effects on ischemia-reperfusion injury.

IMPLICATIONS

It is important to protect the heart from injury by ischemia and reperfusion. The current study demonstrates that in the isolated rat heart, propofol attenuates mechanical, biochemical, and histological changes causes by ischemia and reperfusion.

Pericaval fat collection that mimics thrombosis of the inferior vena cava: demonstration with use of multi-directional reformation CT

PURPOSE

To evaluate the causes for localized fat collection that seemed to be within the subdiaphragmatic inferior vena cava (IVC) on axial computed tomographic (CT) scans.

MATERIALS AND METHODS

Six consecutive patients with presumed intracaval fat collection at routine abdominal CT (n = 2) or thin-section CT of the lung (n = 4) were studied prospectively with helical CT. Three patients had chronic liver diseases. Multi-directional, two-dimensional, reformatted images were obtained from the helical CT data for identification of the relation between the IVC and fat collection. Six patients without intracaval fat collection were studied as control subjects.

RESULTS

On axial CT scans, the fat collection had a round or oval shape (in four of six patients) and was located posteromedial to the IVC (in four of six patients). On coronal reformatted images, the fat collection was outside the IVC between the diaphragm and subdiaphragmatic IVC, which was contiguous to the fat around the subdiaphragmatic esophagus. In the fat collection group, the IVC angled toward the right and narrowed to half in diameter as it passed down to the diaphragm. In the control group, the IVC was straight, although the diameter decreased similarly.

CONCLUSION

A localized fat collection adjacent to the subdiaphragmatic IVC that mimics intracaval fat on axial CT scans is due to acute angulation of the IVC, which is probably a result of anatomic variation, chronic liver disease, or both.

Detection of pancreatic adenocarcinoma: relative value of arterial and late phases of spiral CT

BACKGROUND

Spiral computed tomography (CT) allows the pancreas to be imaged during peak contrast levels owing to the capability of fast data acquisition. The objective of this study was to evaluate the relative value of the arterial and late phases of spiral CT for detecting pancreatic adenocarcinomas.

METHODS

Twenty-two patients with pathologically proved pancreatic adenocarcinomas underwent two-phase spiral CT. The CT scans were performed with 5 mm collimation and 5 mm/s table speed. Images during the arterial and late phases were obtained at 30- and 180-second delays, respectively. The images of the arterial phase were compared with those of the late phase in terms of tumor conspicuity from surrounding pancreatic parenchyma and tumor detectability by means of a 3-point grading system: 1 (poor), 2 (fair), and 3 (good).

RESULTS

In terms of tumor conspicuity from surrounding pancreatic parenchyma, 16 lesions (73%) were good, 5 lesions (23%) were fair, and 1 lesion (4%) was poor during the arterial phase, whereas 6 lesions (27%) were good, 9 lesions (41%) were fair, and 7 lesions (32%) were poor during the late phase (p = 0.0007). The arterial phase was superior to the late phase in 16 patients (73%) and equal in 6 patients (27%). For tumor detectability, 18 lesions (82%) were good, 3 lesions (14%) were fair, and 1 lesion (4%) was poor during the arterial phase, whereas 10 lesions (45%) were good, 7 lesions (32%) were fair, and 5 lesions (23%) were poor during the late phase (p = 0.0033). For detectability, the arterial phase was superior to the late phase in 14 patients (64%) and equal in 8 patients (36%).

CONCLUSION

The arterial phase of spiral CT is superior to the late phase, which is equivalent to conventional CT for detecting pancreatic adenocarcinoma.

Functioning islet cell tumor of the pancreas. Localization with dynamic spiral CT

PURPOSE

The purpose of this study was to evaluate the usefulness of dynamic spiral CT, including multidimensional reformation, in the detection and localization of islet cell tumors of the pancreas.

MATERIAL AND METHODS

Seven patients with histopathologically proven functioning islet cell tumors of the pancreas were studied with 2-phase contrast-enhanced spiral CT. Scanning of the arterial phase and late phase was started 30 s and 180 s, respectively, after injection of 100 ml of contrast medium at a rate of 3 ml/s.

RESULTS

Axial images in the arterial phase depicted the lesions in 5 patients, but in the late phase in only one patient. Multiplanar reformatted images of the arterial phase depicted the lesions in all 7 patients. Maximal intensity projection images demonstrated all lesions with information of their relationship to the vascular structure.

CONCLUSION

Dynamic spiral CT with scanning during the arterial phase and retrospective multidimensional reformation is useful for preoperative detection and localization of small islet cell tumors of the pancreas.

Helical CT anatomy of pancreatic arteries

BACKGROUND

To assess the frequency of visualization of pancreatic arteries in the arterial phase of helical computed tomography (CT).

METHODS

The visibility of pancreatic and peripancreatic arteries in helical CT images was evaluated in 20 consecutive patients who had no evidence of pancreatic disease. CT examinations were performed by using a continuously rotating CT scanner and intravenous injection of contrast media. The scans were taken 35 s after the start of injection and with a table speed of 3 mm/s. Images were reconstructed in 3-mm section increments.

RESULTS

Frequently visualized arteries were the gastroduodenal, anterior and posterior superior pancreaticoduodenal, and right gastroepiploic arteries. Infrequently visualized arteries were the dorsal pancreatic, pancreatica magna, caudal pancreatic, transverse pancreatic, and common, anterior, and posterior inferior pancreaticoduodenal arteries.

CONCLUSION

Helical CT enabled us to recognize small pancreatic arteries, and the evaluation of these arteries should be considered in the staging of pancreatic carcinoma.

Lobular low attenuation of the lung parenchyma on CT: evaluation of forty-eight patients

PURPOSE

Our goal was to analyze patients with pulmonary lobular low attenuation (LLA) on thin section CT with regard to the underlying pulmonary diseases and the dynamic changes occurring in the low attenuation regions during respiration.

METHOD

Forty-eight consecutive patients with LLA on thin section CT were analyzed retrospectively. Forty-six patients (95%) had symptoms related to respiratory disease, such as productive cough (n = 25) and hemoptysis (n = 18). Only two patients, one with chronic pulmonary embolism and one with Takayasu arteritis combined with bronchiectasis, had pulmonary vascular disease. Six patients, four with bronchiectasis and two with vascular disease, were studied with dynamic CT during forced vital capacity maneuver. Attenuation values for LLA areas and adjacent lung were measured and time-density curves were plotted.

RESULTS

Forty-one (85%) patients had bronchiectasis, typically in other than the regions of the LLA. Areas with proximal bronchiectasis showed low attenuation but without notable lobular distribution. Pulmonary vessels in the LLA areas were smaller than those of adjacent normal lung (n = 45). Of 22 patients who underwent pulmonary function tests, 15 had obstructive pattern of impairment. Respiratory dynamic CT showed expiratory air trapping in LLA areas in all six patients. The mean attenuation values of LLA areas were lower than those of the adjacent normal lung by 67 HU at end-inspiration and by 165 HU at end-expiration (p = 0.002).

CONCLUSION

The majority of the patients with LLA shown by thin section CT had bronchiectasis elsewhere in the lung, and evidence of air trapping in the LLA was clearly demonstrated. Bronchiolar obstruction may be the most prevalent cause for the development of LLA.

Spiral CT angiography of the thoracic aorta

Computed tomographic (CT) angiography is a new minimally invasive vascular imaging modality. FOr its clinical use to increase, the advantages and potential applications of this modality must be understood. The clinical applications of CT angiography in the thoracic aorta and its branches include evaluation of congenital aortic anomalies, aortic aneurysm, aortic dissection, Takayasu arteritis, penetrating aortic atherosclerotic ulcer, traumatic aortic injury, the postoperative aorta, arch vessels, and pulmonary sequestration. The advantages of CT angiography over conventional angiography are as follows: (a) high-quality, thin axial sections that demonstrate mural changes, extraluminal pathologic conditions, and spatial relationships with adjacent organs; (b) high contrast resolution and high sensitivity for detecting calcified lesions; (c) angiographic or three-dimensional display of vascular structures and adjacent organs in any projection with a single spiral acquisition; and (d) demonstration of extrinsic causes of vascular compromise. CT angiography has the potential to replace conventional catheter angiography in the diagnosis of many pathologic conditions of the thoracic aorta.

Multiple sequence alignment using simulated annealing

Multiple sequence alignment is a useful technique for studying molecular evolution and analyzing structure-sequence relationships. Dynamic programming of multiple sequence alignment has been widely used to find an optimal alignment. However, dynamic programming does not allow for certain types of gap costs, and it limits the number of sequences that can be aligned due to its high computational complexity. The focus of this paper is to use simulated annealing as the basis for developing an efficient multiple sequence alignment algorithm. An algorithm called Multiple Sequence Alignment using Simulated Annealing (MSASA) has been developed. The computational complexity of MSASA is significantly reduced by replacing the high-temperature phase of the annealing process by a fast heuristic algorithm. This heuristic algorithm facilitates in minimizing the solution set of the low-temperature phase of the annealing process. Compared to the dynamic programming approach, MSASA can (i) use natural gap costs which can generate better solution, (ii) align more sequences and (iii) take less computation time.