Thermal effect of endoscopic thermal vapour ablation on the lung surface in human ex vivo tissue

Purpose: An investigation of the thermal effect and the potential for injury at the lung surface following thermal vapour ablation (InterVapor), an energy-based method of achieving endoscopic lung volume reduction.

Methods: Heated water vapour was delivered to fifteen ex vivo human lungs using standard clinical procedure, and the thermal effect at the visceral pleura was monitored with an infrared camera. The time–temperature response was analysed mathematically to determine a cumulative injury quotient, which was compared to published thresholds.

Results: The cumulative injury quotients for all 71 treatments of ex vivo tissue were found to be below the threshold for first degree burn and no other markers of tissue injury at the lung surface were observed.

Conclusion: The safety profile for thermal vapour ablation is further supported by the demonstration that the thermal effect in a worst-case model is not expected to cause injury at the lung surface.     

Ultrasound-guided percutaneous microwave ablation for hepatic malignancy adjacent to the gallbladder

Abstract

Purpose: The study was performed to assess the safety and efficacy of ultrasound (US)-guided percutaneous microwave (MW) ablation for hepatic malignancy adjacent to the gallbladder. Materials and methods: From January 2011 to December 2013, 49 patients with 51 hepatic tumours adjacent to the gallbladder who underwent US-guided percutaneous MW ablation were included in the study group. A total of 106 patients with 117 hepatic tumours not adjacent to the gallbladder who underwent US-guided percutaneous MW ablation were included in the control group. In the study group the temperature of marginal ablation tissue proximal to the gallbladder was monitored and controlled at 45–54?°C for 5–10?min during the ablation. Ethanol (4.5–13?mL) was injected into the marginal tissue in 27 of 51 tumours of the study group. We compared the results of ablation between the two groups. Results: All patients were successfully treated. A total of 47 of 51 tumours in the study group (92.2%) and 110 of 117 tumours in the control group (94.0%) achieved complete ablation (p?=?0.93). Local tumour progression was found in nine (17.6%) tumours in the study group and 15 (12.8%) tumours in the control group during follow-up after MW ablation (p?=?0.41). No peri-procedural major complications occurred in either group. Conclusions: Under strict temperature monitoring, US-guided percutaneous MW ablation assisted with ethanol injection appears to be safe and can achieve a high rate of complete ablation for the treatment of hepatic malignant tumours adjacent to the gallbladder.     

支气管镜下肺活检联合导管吸引细胞学检查对周围型肺癌的诊断价值

目的:评价支气管镜下利用一次性导管吸引细胞学检查联合肺活检收集肺组织标本,观察该方法对在常规支气管镜下不能看到病灶的周围型肺癌患者的诊断价值.方法:回顾性分析2016年10月到2019年10月共138例胸部CT初诊,临床诊断怀疑为肺癌的患者,肺活检联合导管吸引或者单纯肺活检确诊共124例,分析比较两种方法对不同段支气管...     

Ultrasound-guided high intensity focused ultrasound treatment for extra-abdominal desmoid tumours: Preliminary results

Purpose: The aim of this study was to evaluate the feasibility, safety and therapeutic effects of ultrasound (US)-guided high intensity focused US (HIFU) ablation in the treatment of extra-abdominal desmoid tumours.

Materials and methods: From May 2006 to May 2010, ten consecutive patients with pathologically proven extra-abdominal desmoid tumours were treated by US-guided HIFU ablation. Eight patients with multiple recurrent tumours were treated with a palliative aim, two patients with new solitary tumours were treated with a curative aim. The mean size of the largest tumour was 9.2?cm (range 5.9–12.8?cm). An acoustic power of 300–500?W was used according to the echogenic changes after energy exposure, intermittent HIFU exposure of 2–3?s was applied until the planned target area became hyperechoic on US. Outcome of HIFU ablation was observed by serial contrast-enhanced imaging examinations during follow up.

Results: HIFU ablation was successfully performed without major complications. Large volume coagulation necrosis was obtained in all patients. During a mean follow up of 30 months (range 8–55 months), the treated tumours (n?=?25) shrank significantly (>50% in volume). Complete tumour necrosis was observed in the two patients with solitary new tumours. Two patients received repeat HIFU ablation for enlarged residual tumours. No tumour spread along the treated area was observed in any patient.

Conclusion: US-guided HIFU ablation could be used as an effective minimally invasive therapy for local control of extra-abdominal desmoid tumours.     

High-intensity focused ablation (HIFU) of single benign thyroid nodule rarely alters underlying thyroid function

Abstract

Background: High intensity focused ultrasound (HIFU) is a promising ablation technique for benign thyroid nodules. However, its effect on underlying thyroid function remains unknown. We aimed to evaluate the 6?months changes in serum thyroid stimulating hormone (TSH) and free thyroxine (FT4) after HIFU treatment.

Methods: Eighty-three consecutive patients who underwent single HIFU ablation for symptomatic benign thyroid nodule were analysed. Eligible patients had serum TSH and FT4 checked before treatment (baseline), 1 week, 3 and 6 months following HIFU treatment. Primary endpoints were hypothyroidism (FT4?<?12?pmol/L) and hyperthyroidism (FT4?>?23?pmol/L) in the 6?months following treatment. To express extent of nodule ablation relative to the total gland volume, an ablation volume ratio was calculated by [(Ablated nodule volume/total thyroid volume)/(total thyroid volume)]?×?100.

Results: Relative to baseline, 1-week serum TSH significantly dropped (from 1.16 to 0.76 mIU/L, p?<?0.001) while 1-week serum FT4 significantly rose (from 16.0?to 17.8?pmol/L, p?<?0.001). However, 3- and 6-months TSH and FT4 did not changed significantly from baseline (p?>?0.05). No patients developed hyperthyroidism while one (1.4%) developed hypothyroidism (FT4?=?11?pmol/L) at 3 months and 6 months. Interestingly, this patient had a previous lobectomy and an ablation volume ratio of 64.00%.

Conclusions: Hypothyroidism following single HIFU ablation occurred rarely (1.4%) and resulted in little clinical relevance. Given that only one patient developed hypothyroidism following single HIFU ablation, it remains unclear how patients with different amount of parenchyma and relative extent of ablation may affect subsequent thyroid function.     

Percutaneous microwave ablation for liver cancer adjacent to the diaphragm

Purpose: The aim of the study was to prospectively evaluate the safety and effectiveness of percutaneous microwave (MW) ablation for liver cancer adjacent to the diaphragm.

Materials and methods: From May 2005 to June 2008, 89 patients with 96 hepatic lesions adjacent to the diaphragm (the shortest distance from the lesion margin to the diaphragm less than 5?mm), who underwent ultrasound (US)-guided percutaneous MW ablation, were included in the study group. A total of 100 patients with 127 hepatic lesions not adjacent to the diaphragm (the shortest distance from the lesion to the diaphragm and the first or second branch of the hepatic vessels more than 10?mm), who underwent US-guided percutaneous MW ablation, were included in the control group. During the ablation the temperature of marginal ablation tissue proximal to the diaphragm was monitored and controlled at 50°–60°C for more than 10?min in the study group. We compared the results of ablation between the two groups.

Results: A total of 91 of 96 tumours (94.8%) in the study group and 123 of 127 tumours (96.9%) in the control group achieved complete ablation (P?>?0.05). Local tumour progression was found in 18 of 96 tumours (18.8%) in the study group and 21 of 127 tumours (16.5%) in the control group during follow-up after MW ablation (P?>?0.05). No major complications occurred in either group.

Conclusions: Under strict temperature monitoring, percutaneous MW ablation is safe and can achieve a high complete ablation rate for the treatment of hepatic tumours adjacent to the diaphragm.     

Feasible temperature of percutaneous microwave ablation of dog liver abutting the bowel

Purpose: This study used a dog model to determine the optimal temperature of percutaneous microwave ablation that causes complete necrosis of liver but not the adjacent bowel, supporting the use of this method to specifically and effectively treat liver tumour abutting the bowel.

Materials and methods: Ultrasound-guided percutaneous microwave ablation of liver abutting the bowel was performed on healthy adult dogs. Temperature of the ablation margin was monitored and controlled through inserted thermal monitoring needles. Dogs were divided into three groups and received microwave ablation at 75–95°C, 65–75°C, or 55–65°C. Imaging and histological examination were used to evaluate the damage of the bowel adjacent to the ablated liver.

Results: Within one hour of treatment, the bowel adjacent to the ablated liver was seriously burned in the group receiving 75–95°C microwave ablation. Inflammation and congestion were found in the submucosa of the bowel in the group receiving 65–75°C microwave ablation. Minor inflammation was found in the mucosa of the bowel in the group receiving 55–65°C microwave ablation. Moreover, in the group receiving 55–65°C microwave ablation, ablated liver areas were covered with omenta, and histological examination revealed inflammatory reaction of the omenta 28 days after ablation.

Conclusions: Microwave ablation at 55–65°C for 6?min is preferred for ablation of liver tissue abutting the bowel in dogs. These findings may provide some valuable reference for percutaneous microwave ablation of human liver tumour adjacent to the bowel.     

Efficacy and safety of artificial ascites in assisting percutaneous microwave ablation of hepatic tumours adjacent to the gastrointestinal tract

Purpose: This study assessed the efficacy and safety of artificial ascites in assisting ultrasound-guided percutaneous microwave (MW) ablation of hepatic tumours adjacent to the gastrointestinal tract. Materials and methods: In total, 36 patients with 36 hepatic malignancies who underwent the introduction of artificial ascites before ultrasound-guided percutaneous MW ablation were included in this retrospective study. The separation success rate of the artificial ascites, the technique effectiveness of the MW ablation, local tumour progression and complications were assessed. Results: The separation success rate of the artificial ascites for 36 hepatic tumours adjacent to the gastrointestinal tract was 88.9% (32/36). The technical effectiveness of MW ablation in 32 cases with successful separation was 96.9% (31/32). During follow-up (mean, 12.1?±?7.2 months), local tumour progression was found in five of 31 patients (16.1%). One patient experienced a major complication (infection of the hepatic ablation zone). Conclusions: Ultrasound-guided percutaneous MW ablation assisted by artificial ascites is a safe and effective method for the treatment of primary and metastatic hepatic tumours adjacent to the gastrointestinal tract and can achieve good local control of such tumours.     

Technical aspects of osteoid osteoma ablation in children using MR-guided high intensity focussed ultrasound

Background: Osteoid osteoma (OO) is a painful bone tumour occurring in children and young adults. Magnetic resonance imaging-guided high intensity focussed ultrasound (MR-HIFU) allows non-invasive treatment without ionising radiation exposure, in contrast to the current standard of care treatment with radiofrequency ablation (RFA). This report describes technical aspects of MR-HIFU ablation in the first 8 paediatric OO patients treated in a safety and feasibility clinical trial (total enrolment of up to 12 patients).

Materials and methods: OO lesions and adjacent periosteum were treated with MR-HIFU ablation in 5–20 sonications (sonication duration?=?16–48?s, frequency?=?1.2?MHz, acoustic power?=?20–160?W). Detailed treatment workflow, patient positioning and coupling strategies, as well as temperature and tissue perfusion changes were summarised and correlated.

Results: MR-HIFU ablation was feasible in all eight cases. Ultrasound standoff pads were shaped to conform to extremity contours providing acoustic coupling and aided patient positioning. The energy delivered was 10?±?7?kJ per treatment, raising maximum temperature to 83?±?3?°C. Post ablation contrast-enhanced MRI showed ablated volumes ranging 0.46–19.4?cm³ extending further into bone (7?±?4?mm) than into soft tissue (4?±?6?mm, p?=?0.01, Mann–Whitney). Treatment time ranged 30–86?min for sonication and 160?±?40?min for anaesthesia. No serious treatment-related adverse events were observed. Complete pain relief with no medication occurred in 7/8 patients within 28 days following treatment.

Conclusions: MR-HIFU ablation of painful OO appears technically feasible in children and it may become a non-invasive and radiation-free alternative for painful OO. Therapy success, efficiency, and applicability may be improved through specialised equipment designed more specifically for extremity bone ablation.     

Treatment of liver tumours adjacent to hepatic hilum with percutaneous microwave ablation combined with ethanol injection: A pilot study

Purpose: To evaluate the feasibility, safety and efficacy of ultrasound-guided percutaneous microwave ablation combined with percutaneous ethanol injection in the treatment of liver tumours adjacent to the hepatic hilum.

Materials and methods: From December 2005 to April 2008, 18 consecutive patients with 18 pathologically proven or clinically diagnosed liver tumours (15 HCCs, three metastatic tumours) adjacent to the hepatic hilum underwent ultrasound-guided percutaneous microwave ablation combined with percutaneous ethanol injection. One or two microwave antennae were inserted and placed at designated places in the tumour. One or two ethanol needles were placed at the tumour periphery near the hepatic hilum. An aliquot of 2–10?mL of absolute ethanol was injected into the tumour at the same time as microwave emission. A thermocouple was placed directly abutting the bile ducts of the hepatic hilum to monitor temperature in real time during ablation to avoid thermal injury.

Results: No more than two sessions were performed to complete the treatment (one session for 10 patients, two sessions for eight, mean 1.4 sessions per patient). Complete ablation was achieved in 94.4% (17 out of 18 cases). In a median follow up of 15 months (range 4 to 27 months, mean 13.5 months), no mortality or complications occurred. Local tumour progression was noted in one patient 12 months after treatment.

Conclusion: A combination of ultrasound-guided percutaneous microwave ablation and percutaneous ethanol injection assisted with real-time temperature monitoring appears to be feasible and effective in the treatment of liver tumours adjacent to the hepatic hilum, and initial experience with safety is promising.     

In vivo wound healing and dermal matrix remodelling in response to fractional CO2 laser intervention: Clinicopathological correlation in non-facial skin

Purpose: Ablative fractional photothermolysis is a new concept for treatment of aged skin. Despite the low frequency of side effects there are now several reports about scarring, especially in non-facial regions like the neck. Our study aimed to investigate the in vivo wound healing process and remodelling in an area prone to scarring using a fractional ablative CO₂ laser with three different energy protocols.

Materials and methods: Six patients with photo-damaged skin received a single fractional ablative treatment using a 250-µm scanning CO₂ laser. Three areas on the neck were treated with 50, 100 and 300?mJ/microbeam at densities of 200, 150 and 100/cm², respectively. Biopsies were taken from untreated skin (control) and 10?minutes, 3 days, 14 days, 21 days and 28 days post-intervention.

Results: Fractional ablation with higher energies resulted in increased total thermal damage. Overall, 50?mJ was effective up to the superficial dermis, 100?mJ up to the mid-dermis, and 300?mJ resulted in deep dermal ablation. The intensity of lymphocytic inflammation and dermal remodelling correlated with the total amount of thermal damage. At 300?mJ, granuloma was present and persisted for at least 4 weeks as opposed to clinical healing, which was completed?<?2 weeks.

Conclusions: With the above-mentioned low and medium parameter settings, ablative fractional photothermolysis is safe and effective in non-facial skin. However, dermal remodelling continues for up to 4 weeks, which should be the minimum space between treatment sessions. Higher energies may induce granuloma formation, possibly a sign of an overstrained remodelling capacity.     

Ultrasound-guided percutaneous microwave ablation of solitary T1N0M0 papillary thyroid microcarcinoma: Initial experience

Purpose: The aim of this study was to evaluate the feasibility, safety and efficacy of ultrasound-guided percutaneous microwave (MW) ablation for solitary T1N0M0 papillary thyroid microcarcinoma. Materials and methods: A total of 21 patients (six men and 15 women; age range, 29–81 years; mean, 52.1?±?13.6 years) with 21 nodules of pathologically proven solitary papillary carcinoma 3.7 to 10.0?mm in diameter without clinically apparent lymph node, or distant metastasis at diagnosis (T1N0M0) were treated with MW ablation in our department. Microwaves were emitted at 40?W for 400?s and prolonged as necessary to attain confluent ablation zones. All patients were treated with levothyroxine after MW ablation to maintain thyroid stimulating hormone (TSH) levels below 0.1?mU/L. Follow-up consisted of ultrasound in 21 patients, biopsy in five patients, and surgical treatment in three patients. Results: Four patients complained of hoarseness immediately after the MW ablation procedure, and all of them recovered within 3 months spontaneously. All tumours were completely ablated at a single session and no serious or permanent complications occurred. No recurrence at the treatment site and no distant metastases were detected, with a mean follow-up of 11 months. Histological examination showed no evidence of a tumour in the treated lesions in eight patients. Follow-up ultrasound examinations showed disappearance of previously detected colour Doppler flow, as well as mass shrinkage, or both. Conclusion: During the short-term follow-up period, ultrasound-guided percutaneous MW ablation appears to be a safe and effective technique for solitary T1N0M0 papillary thyroid microcarcinoma.     

Early phase II study of S-1, a new oral fluoropyrimidine, for advanced non-small-cell lung cancer

Background. The efficacy and safety of S-1, a new oral fluoropyrimidine, were evaluated in patients with non-small-cell lung cancer (NSCLC). The objective of this study was to determine whether the drug should be investigated in a late phase II study. Methods. Each treatment course consisted of an oral dose of S-1, 50 mg/body or 75 mg/body, twice a day for 28 days, followed by a 2-week washout period. Results. Fifty-six eligible patients were enrolled. Five of the 40 previously untreated patients (12.5%; 90% confidence interval, 6.2%–23.5%) showed a partial response (PR), and no tumor response was observed in the 16 previously treated patients. The median survival duration in all eligible patients was 8.4 months, with a 1-year survival rate of 27.3%. The incidences of grade 3 or more severe adverse effects were: anemia, 5.4%; leukopenia, 5.4%; neutropenia, 5.4%; thrombocytopenia, 1.8%; anorexia, 3.6%; diarrhea, 3.6%; and general fatigue, 5.4%. These effects disappeared after cessation of the drug or appropriate treatment. One patient died as a result of aggravated interstitial pneumonitis, but the relationship of this event to S-1 was not clear. Conclusion. S-1 showed modest activity with mild toxicity in the treatment of non-small-cell lung cancer. Based on this result, we will progress to the next stage of a late phase II study for advanced NSCLC, and a phase II study of S-1 and cisplatin for advanced gastric cancer. Final results will be reported as they are obtained. Received: February 13, 2001 / Accepted: August 28, 2001     

Pathological effects of lung radiofrequency ablation that contribute to pneumothorax,using a porcine model

Objectives: The incidence of pneumothorax is 7 times higher after lung radiofrequency ablation (RFA) than after lung biopsy. The reasons for such a difference have never been objectified. The histopathologic changes in lung tissue are well-studied and established for RF in the ablation zone. However, it has not been previously described what the nature of thermal injury might be along the shaft of the RF electrode as it traverses through normal lung tissue to reach the ablation zone. The purpose of this study was to determine the changes occurring around the RF needle along the pathway between the ablated zone and the pleura.

Material and methods: In 3 anaesthetised and ventilated swine, 6 RFA procedures (right and left lungs) were performed using a 14-gauge unipolar multi-tined retractable 3?cm radiofrequency LeVeen probe with a coaxial introducer positioned under CT fluoroscopic guidance. In compliance with literature guidelines, we implemented a gradually increasing thermo-ablation protocol using a RF generator. Helical CT images were acquired pre- and post-RFA procedure to detect and evaluate pneumothorax. Four percutaneous 19-gauge lung biopsies were also performed on the fourth swine under CT guidance. Swine were sacrificed for lung ex vivo examinations, scanning electron microscopy (SEM) and pathological analysis.

Results: Three severe (over 50?ml) pneumothorax were detected after RFA. In each one of them, pathological examination revealed a fistulous tract between ablation zone and pleura. No fistulous tract was observed after biopsies.

In the 3 cases of severe pneumothorax, the tract was wide open and clearly visible on post procedure CT images and SEM examinations. The RFA tract differed from the needle biopsy tract. The histological changes that are usually found in the ablated zone were observed in the RFA tract’s wall and were related to thermal lesions. These modifications caused the creation of a coagulated pulmonary parenchyma rim between the thermo-ablation zone and the pleural space. The structural properties of the damage can explain why the RFA tract is remains patent after needle withdrawal.

Conclusion: Our study demonstrates for the first time that the changes around the RF needle are the same as in the ablated zone. The damage could create fistulous tracts along the needle path between thermo-ablation zone and pleural space. These fistulas could certainly be responsible for severe pneumothorax that occurs in many patients treated with lung RFA.     

Ultrasound-guided percutaneous microwave ablation of adrenal metastasis: Preliminary results

Purpose: To evaluate the feasibility, safety and therapeutic effects of ultrasound (US)-guided percutaneous microwave (MW) ablation in the treatment of adrenal metastasis.

Materials and methods: From May 2006 to April 2008, five consecutive patients with pathologically proven unilateral adrenal metastases with a diameter of 2.3 to 4.5 cm were treated by US-guided percutaneous MW ablation. Four metastases were in the right side, one metastasis was in the left side. For each application, two cooled-shaft needle antennae were percutaneously inserted into the tumour under real-time US guidance. One thermocouple needle was inserted at the periphery of the tumour to monitor temperature in real-time during MW ablation. MW emission was ended when the entire tumour became hyperechoic and the temperature at the tumour border reached 54°C for at least 3 min. Technical success was defined as loss of tumour enhancement on contrast-enhanced imagings.

Results: All adrenal metastases were completely ablated after scheduled MW ablation sessions (mean, 1.2 sessions, range, 1 to 2 sessions). No major complications related to MW ablation occurred. In a median follow-up of 19 months (range 8 to 31 months), persistent absence of tumour enhancement was observed in the treated tumour in all patients.

Conclusions: US-guided percutaneous MW ablation appears to be a safe and effective therapy in selected adrenal metastasis.     

Previous lung disease and lung cancer risk among women (United States)

Objective:The association between previous lung diseases (PLD) and lung cancer risk has not been studied extensively. We conducted a registry-based case–control study to examine the relation between previous lung diseases and lung cancer among women in Missouri. Methods:Incident cases (n = 676) were identified through the Missouri Cancer Registry for the period 1 January 1993 to 31 January 1994. Controls (n = 700) were selected through drivers' license files and Medicare files. Results:Whether analyzing all respondents or in-person interviews only, elevated effect estimates were noted for several types of PLD. Elevated relative risk estimates were shown for chronic bronchitis (odds ratio [OR] = 1.7; 95% confidence interval [CI] = 1.2–2.3), emphysema (OR = 2.7; 95% CI = 1.8–4.2), pneumonia (OR = 1.6; 95% CI = 1.2–2.0), and for all PLDs combined (OR = 1.5; 95% CI = 1.2–1.9). Analysis of only direct interviews did not show a substantial or consistent pattern of change in relative risk estimates. Because PLDs identified close to the time of cancer diagnosis could conceivably be misdiagnosed, resulting from early lung cancer symptoms, we evaluated the effects on risk estimates of a latency exclusion of up to threeyears. When these exclusions were taken into account, ORs remained statistically significantly elevated only for emphysema. Conclusion:When earlier epidemiologic findings and underlying biological and genetic factors are taken into account, an association between PLD and lung cancer is plausible.     

Dynamic MR Based Analysis of Tumor Movement in Upper and Mid Lobe Localized Lung Cancer

Background and purpose: Tumor motion is a very important factor in the radiotherapy of lung cancer. Uncertainty resulting from tumor movement must be considered in 3D therapy planning especially in case of IMRT or stereotactic therapy. The aim of our dynamic MR based study was to detect tumor movements in upper and mid lobe lung tumors. Patient and methods: Twenty-four patients with newly diagnosed stage II-IV lung cancer were enrolled into the study. According to tumor localization in the right S1–S3 segments 9, in the right S4–S6 segments 2, in the left S1–S3 segments 9 and in the left S4–S6 segments 4 lesions were detected. In normal treatment position individual dynamic MR examinations were performed in axial, sagittal and coronal planes (100 slices/30 sec). For tumor motion analysis E-RAD PAC's software was used. Results: Movements of the tumor under normal breathing conditions were registered in the three main directions. The mean antero-posterior deviation was 0,109 cm (range: 0,063 cm–0,204 cm), the mean medio-lateral deviation was 0,114 cm (range: 0,06 cm– 0,244 cm). The greatest deviation was measured in cranio–caudal direction (mean: 0,27 cm, range: 0,079 cm– 0,815 cm). The mean direction independent deviation was 0,18 cm (range: 0,09 cm– 0,48 cm). Conclusion: Dynamic MR is a sensitive and well tolerated method for tumor motion monitoring in high precision 3D therapy planning of lung cancer patients. Our results demonstrate that tumors located in the upper and mid lobes have moderate breath synchronous movements. The greatest deviation occur in cranio–caudal direction.     

Invasive adenocarcinoma of the lung is associated with the upper lung regions

Objectives

We postulated that ventilation–perfusion (V/Q) relationships within the lung might influence where lung cancer occurs. To address this hypothesis we evaluated the location of lung adenocarcinoma, by both tumor lobe and superior–inferior regional distribution, and associated variables such as emphysema.

Materials and Methods

One hundred fifty-nine cases of invasive adenocarcinoma and adenocarcinoma with lepidic features were visually evaluated to identify lobar or regional tumor location. Regions were determined by automated division of the lungs into three equal volumes: (upper region, middle region, or lower region). Automated densitometry was used to measure radiographic emphysema.

Results

The majority of invasive adenocarcinomas occurred in the upper lobes (69%), with 94% of upper lobe adenocarcinomas occurring in the upper region of the lung. The distribution of adenocarcinoma, when classified as upper or lower lobe, was not different between invasive adenocarcinoma and adenocarcinoma with lepidic features (formerly bronchioloalveolar cell carcinoma, P = 0.08). Regional distribution of tumor was significantly different between invasive adenocarcinoma and adenocarcinoma with lepidic features (P = 0.001). Logistic regression analysis with the outcome of invasive adenocarcinoma histology was used to adjust for confounders. Tumor region continued to be a significant predictor (OR 8.5, P = 0.008, compared to lower region), whereas lobar location of tumor was not (P = 0.09). In stratified analysis, smoking was not associated with region of invasive adenocarcinoma occurrence (P = 0.089). There was no difference in total emphysema scores between invasive adenocarcinoma cases occurring in each of the three regions (P = 0.155). There was also no difference in the distribution of region of adenocarcinoma occurrence between quartiles of emphysema (P = 0.217).

Conclusion

Invasive adenocarcinoma of the lung is highly associated with the upper lung regions. This association is not related to smoking, history of COPD, or total emphysema. The regional distribution of invasive adenocarcinoma may be due to V/Q relationships or other local factors.     

MRI-guided focused ultrasound ablation of lumbar medial branch nerve: Feasibility and safety study in a swine model

Purpose: About 10–40% of chronic low back pain cases involve facet joints, which are commonly treated with lumbar medial branch (MB) radiofrequency neurotomy. Magnetic resonance imaging-guided focused ultrasound (MRgFUS), a non-invasive, non-ionising ablation modality used to treat tumours, neuropathic pain and painful bone metastasis can also be used to disrupt nerve conduction. This work’s purpose was to study the feasibility and safety of direct MRgFUS ablation of the lumbar MB nerve in acute and subacute swine models.

Materials and methods: In vivo MRgFUS ablation was performed in six swine (three acute and three subacute) using a clinical MRgFUS system and a 3-T MRI scanner combination. Behavioural assessment was performed, and imaging and histology were used to assess the treatment.

Results and conclusions: Histological analysis of the in vivo studies confirmed thermal necrosis of the MB nerve could be achieved without damaging the spinal cord or adjacent nerve roots. MRgFUS did not cause changes in the animals’ behaviour or ambulation.     

Morphological and functional recovery of rat small intestine following localized hyperthermia

Structural and functional changes in the rat small intestine following localized hyperthermia were examined. In anaesthetized male Sprague-Dawley rats a 10 cm segment of mid-small intestine was temporarily exteriorized, suspended in a cup containing Krebs-Ringer solution, and either heated at 43.5°C or sham-heated at 38°C for 45 min. The intestinal segments were studied 1, 4, 7, 21 and 42 days later by histopathological examination, determination of wet weight, dry weight and gross segment area, and by measuring absorption of 15 mM D(+)-glucose containing ¹⁴C-labelled D(+)-glucose as a tracer. Intestinal glucose transport was assessed by two different techniques: The everted sac method (in vitro) and luminal perfusion-recirculation (in vivo). After 1 day, heated intestinal segments exhibited marked mucosal damage, consisting of loss of epithelial cells and destruction of villi. Re-epithelialization had occurred by day 4, but mucosal architecture remained abnormal throughout the observation period. Hyperthermia caused significant thickening of the intestinal wall: At 4 days the thickening was due to oedema, whereas at 42 days tissue mass per cm² in heated segments had increased by approximately 53 per cent compared with sham-heated control segments. At 1 day, net glucose transport in vitro in heated segments was reduced to 20 per cent and the serosal/mucosal concentration ratio to 57 per cent of that of control segments. In vivo, glucose transport in heated intestine at 4 days was 45 per cent of that of controls. From 4 days on, glucose transport improved gradually, and at 42 days there was no significant difference between heated and sham-heated animals. It is concluded that hyperthermia of the small intestine causes morphological alterations lasting at least 6 weeks, and a pronounced but temporary decrease in the absorption of glucose.