Does tumor type affect local control by radiofrequency ablation in the lungs?

Objective

: To retrospectively evaluate the effect of tumor type on local control by radiofrequency ablation in the lungs.

Materials and methods

: This study included 252 lung tumors (mean size, 13.5 mm) in 105 patients (73 men and 32 women; mean age, 66.6 years) who underwent radiofrequency ablation with a multitined expandable electrode. Those tumors comprised five tumor types: primary lung cancer (n = 35) and pulmonary metastases from colorectal cancer (n = 117), lung cancer (n = 23), renal cell carcinoma (n = 49), and hepatocellular carcinoma (n = 28). Local control was evaluated with contrast-enhanced computed tomography. The overall local control rates were estimated as well as those for each tumor type using the Kaplan-Meier analysis. Local control rates for a given tumor type were compared with those for the four other types. Then, multivariate multilevel analysis was performed using the variables of tumor type, tumor size, contact with a vessel or bronchus, and procedure period.

Results

: The overall local control rates were 97%, 86%, 81%, and 76% at 6, 12, 18, and 24 months, respectively. Local control rates varied among the tumor types, and metastatic colorectal cancer showed significantly (P = .023) higher local control rates than those of the four other types. However, multivariate analysis indicated that the relative risk of local progression for a given tumor type was comparable to the risks for the four other types.

Conclusion

: Tumor type per se did not significantly influence local control.     

Percutaneous ablation of renal tumors: radiofrequency ablation or cryoablation?

Percutaneous ablation of renal tumors, including radiofrequency ablation and cryoablation, are increasingly being used for small tumors as an alternative to surgery for poor surgical candidates. Compared to radiofrequency ablation, cryoablation has several advantages: improved volume control and preservation of adjacent structures due to the excellent depiction of the ice ball on CT and MRI; better protection of the collecting system for central tumor with reduced risk of postprocedural urinary fistula. The main pitfall of cryoablation is the higher cost. Therefore, cryoablation should be reserved for the treatment of complex tumors. In this article, we will review the different steps of percutaneous renal tumor ablation procedures including patient selection, technical considerations, and follow-up imaging.     

Contrast enhanced ultrasound: Should it play a role in immediate evaluation of liver tumors following thermal ablation?

Purpose

To compare the accuracy of immediate CEUS with results of 24-h CEUS and MDCT in early evaluation of liver tumors following thermal ablation, using the combined results of a 3 month follow-up MDCT and CEUS as a reference standard.

Subjects and methods

From our database, we selected patients who underwent a thermal ablation immediately followed by CEUS (within 5–10 min) between February 2009 and February 2011. There were 92 patients (median age 73 years), two of whom had repeat ablation during the study period for a total of 94 tumors. Sixty tumors were treated with radiofrequency and 34 with microwave ablation. All patients underwent CEUS and CT examinations at 24 h. For patients with more than one treated tumor in the same session, the lesion imaged post-procedural and at 24-h with CEUS in all vascular phases was selected. All measurements of the necrotic zone, as an avascular zone, were performed during the portal-venous phase. Immediate post-procedural CEUS and 24 h CEUS and MDCT were blindly reviewed by two radiologists. One radiologist blindly reviewed the follow-up imaging. The mean diameters of the necrotic zone at post-procedural CEUS, and CEUS and MDCT at 24 h were compared and diagnostic accuracy to detect residual tumor calculated for each index tests compared to 3-months follow-up imaging.

Results

The mean diameter of the necrotic zone was: 29 ± 9 mm at post-procedural CEUS, 34 ± 10 mm at 24 h CEUS and 35 ± 11 mm at 24 h MDCT. Mean diameter of the necrotic zone was significantly smaller at post-procedural CEUS compared to either CEUS or MDCT at 24 h (p < 0.001 for all).With a 95% confidence interval, the sensitivity was 25% (11–47%) for immediate CEUS, 20% (8–42%) for CEUS at 24-h, and 40% (22–61%) for CT at 24-h. Specificity was 96% (89–99%) for immediate CEUS, 97% (91–99%) for CEUS at 24-h, and 97% (91–99%) for CT at 24-h.

Conclusions

Diagnostic accuracy of post-procedural CEUS in early evaluation of liver tumors following thermal ablation is comparable to both CEUS and MDCT performed at 24 h. Therefore, post-procedural CEUS can be used to detect and retreat residual viable tissue in the same ablation session.     

Diffusion MR imaging in glioma: does it have any role in the pre-operation determination of grading of glioma?

AIM: To investigate the role of the diffusion MR weighted sequence in the pre-operative grading of gliomas, and its application in defining the different components of these tumours. MATERIALS AND METHODS: Seventeen patients with gliomas (eight high grade, nine low grade) had diffusion weighted imaging. Apparent diffusion coefficients (ADCs) of different components of tumours were measured. RESULTS: ADC of the cystic portion of the tumour was significantly higher than ADCs of the enhanced tumour, non-enhanced tumour and perifocal oedema (P < 0.01). No significant difference in ADC values between low grade and high grade glioma (P > 0.7) was found nor was there any difference between oligoglioma and non-oligoglioma (P > 0.29). CONCLUSION: ADC value was useful to differentiate the cystic from the solid components of the tumours. However, it was not useful in pre-operative grading of glioma.     

Percutaneous radiofrequency ablation of liver tumors with the LeVeen probe: is roll-off predictive of response?

PURPOSE: The LeVeen radiofrequency (RF) probe uses roll-off of electrical impedance as the endpoint for RF cautery of hepatic tumors. The purpose of this study is to determine the relation of roll-off to local control of hepatic tumors. MATERIALS AND METHODS: Twenty hepatic tumors, including 10 hepatomas and 10 metastases, were treated. Lesions ranged from 1.4 cm to 6.0 cm in diameter; 13 (57%) were smaller than 3.0 cm. Each lesion was ablated with use of the LeVeen 15-gauge RF needle according to the manufacturer's protocol. Five patients underwent chemoembolization the day before. Patients were followed up with contrast-enhanced computed tomography or magnetic resonance imaging at 1 month and every 3 months thereafter. RESULTS: Among the 20 lesions, roll-off was achieved at all burn locations in 11 (55%), no burn locations in eight (40%), and two of three burn locations in one (5%). Roll-off was observed in all patients who had undergone chemoembolization the day before. Six local recurrences occurred, five after RF ablation without roll-off and one after RF ablation with roll-off. According to life-table analysis, the local recurrence rate at 6 months without roll-off was 43% and with roll-off was 15% (P =.024; OR = 8.3; 95% CI = 0.93-66). CONCLUSION: Roll-off is a significant predictor of local control after RF ablation. Strategies to enhance roll-off, such as concurrent embolization, may be important to optimize the therapeutic effect of this device.     

Qualitative radiology assessment of tumor response: does it measure up?

Our purpose was to assess whether a simpler qualitative evaluation of tumor response by computed tomography is as reproducible and predictive of clinical outcome as the Response Evaluation Criteria in Solid Tumors (RECIST) and World Health Organization (WHO) methods. This study was a two-reader retrospective evaluation in which qualitative assessment resulted in agreement in 21 of 23 patients with metastatic colorectal carcinoma (91.3%, kappa=0.78; 95% CI, 0.51–1.00). Hepatic metastases were classified as increased, decreased, or unchanged, compared with agreement in 20 of 23 patients (87.0%) for RECIST (kappa=0.62; 95% CI, 0.23–1.00) and WHO (kappa=0.67; 95% CI, 0.34–1.00) methods. Patients were placed into partial response, stable disease, and disease progression categories. Time to progression of disease was better predicted qualitatively than by RECIST or WHO. Our pilot data suggest that our qualitative scoring system is more reproducible and predictive of patient clinical outcome than the RECIST and WHO methods.     

Primary intraperitoneal solitary fibrous tumor in mesentery: How does it present?

Intra-abdominal solitary fibrous tumor (SFT), also known as hemangiopericytoma, is rare, especially for those with a mesenteric location, and only a few cases have been reported. Distinguishing a hemangiopericytoma from other intra-abdominal benign or malignant tumors can be difficult, as they have similar presentations on both computed tomography and magnetic resonance imaging. In the present study, the records for a 31-year-old Vietnamese woman who underwent abdominal surgery for greater omental tumor resection and received histopathological results revealing SFT are retrospectively reviewed. The case is discussed and similar reported cases are reviewed. Due to the aggressive behavior and high rate of postoperative recurrence associated with SFT, a thorough understanding of the radiologic and histopathological features of the disease is necessary to achieve an appropriate diagnosis and treatment.     

Chemical shift MR imaging of hyperattenuating (>10 HU) adrenal masses: does it still have a role?

PURPOSE: To evaluate chemical shift magnetic resonance (MR) imaging for the characterization of hyperattenuating adrenal masses. MATERIALS AND METHODS: Adrenal MR images obtained from January 1998 to February 2003 were reviewed. Patients were excluded if they did not undergo unenhanced computed tomography or did not have an adrenal mass with attenuation higher than 10 HU, adequate follow-up, or pathologic diagnosis for use as a reference standard. A diagnosis of adenoma required at least 24 weeks of stability on images. Thirty-eight masses in 36 patients were identified (27 adenomas, nine metastases, one adrenocortical oncocytoma, and one pheochromocytoma). Signal intensity (SI) decrease between in-phase and opposed-phase MR images was measured for the entire mass and normalized to the renal parenchymal SI. In 21 of 36 (58%) patients, dual-echo single-breath-hold MR imaging was used to eliminate misregistration. RESULTS: The attenuation of 61% (23 of 38) of all masses and 70% (19 of 27) of adenomas was 10-30 HU. With a threshold of 20% SI decrease, the sensitivity of chemical shift MR imaging for hyperattenuating adenoma was 67% (18 of 27 masses). When considering masses with attenuation of 10-30 HU, the sensitivity for adenoma was 89% (17 of 19 masses) and remained reasonable at 75% (six of eight masses) for adenomas with attenuation of 20-30 HU. Only one adenoma with attenuation higher than 30 HU had SI decrease of more than 20%. Specificity for diagnosis of adenoma was 100% (11 of 11). CONCLUSION: In certain circumstances, chemical shift MR imaging is a reasonable second imaging test for further characterization of a hyperattenuating adrenal mass.     

Defecography: does parity play a role in the development of rectal prolapse?

Few studies related to parity address the changes in anorectal function in women. Since the majority of patients with rectal prolapse are women, we undertook this study to assess the role of parity in the development of rectal prolapse. We retrospectively reviewed defecography studies performed on 354 female patients over a 10-year period. Studies noting the presence of intra-anal and external rectal prolapse (full thickness protrusion of the rectum into and through the anal sphincter) were reviewed. Cases with intrarectal or hidden rectal prolapse, a condition of lesser clinical importance, were excluded. The obstetric histories of the patients with rectal prolapse (n = 27) were compared to those of patients without rectal prolapse (n = 88). There was a larger proportion of nulliparous women in the rectal prolapse group than in the group without rectal prolapse, suggesting that factors in addition to parity play a role in the development of rectal prolapse. However, parous women with rectal prolapse had delivered significantly more children (3.3) than parous women without prolapse (2.5) (P = 0.03). The exact cause of rectal prolapse remains unclear. Childbearing appears to play a limited role in its pathogenesis since nulliparous women are also at risk of developing rectal prolapse. Received: 27 November 1997; Revision received: 15 April 1998; Accepted: 13 May 1998     

What does it take to have a high-grade pivot shift?

The pivot shift is the most specific clinical test to assess pathological knee joint rotatory laxity following ACL injury. This article attempts to describe the anatomic structures responsible for creating a high-grade pivot shift and their potential role in customizing ACL reconstruction. A review of the literature demonstrates that disruption of the secondary stabilizers of anterior translation of the lateral compartment including the lateral meniscus, anterolateral capsule, and IT band contributes to a high-grade pivot shift in the ACL-deficient knee. The morphology of the lateral tibial plateau, including increased posteroinferior tibial slope and small size, can also contribute to high-grade pivot shift. Factors that may decrease the grade of the pivot shift include medial compartment injury, MCL injury, patient guarding, and osteoarthritis. In conclusion, a high-grade pivot shift in the ACL-deficient knee is often associated with incompetence of the lateral soft tissue envelope. Rotatory laxity as assessed by the pivot shift may also be falsely underestimated by concomitant injuries.     

Radiofrequency and microwave tumor ablation in patients with implanted cardiac devices: Is it safe?

Purpose

To identify malfunction of implanted cardiac devices during or after thermal ablation of tumors in lung, kidney, liver or bone, using radiofrequency (RF) or microwave (MW) energy.

Materials and methods

After providing written consent, 19 patients (15 men and 4 women; mean age 78 years) with pacemakers or pacemaker/defibrillators underwent 22 CT image-guided percutaneous RF or MW ablation of a variety of tumors. Before and after each procedure, cardiac devices were interrogated and reprogrammed by a trained cardiac electrophysiology fellow. Possible pacer malfunctions included abnormalities on electrocardiographic (EKG) monitoring and alterations in device settings. Our institutional review board approved this Health Insurance Portability and Accountability Act-compliant study. Informed consent for participation in this retrospective study was deemed unnecessary by our review board.

Results

During 20 of 22 sessions, no abnormalities were identified in continuous, EKG tracings or pacemaker functions. However, in two sessions significant changes, occurred in pacemaker parameters: inhibition of pacing during RF application in one, session and resetting of mode by RF energy in another session. These changes did not, result in hemodynamic instability of either patient. MW ablation was not associated with, any malfunction. In all 22 sessions, pacemakers were undamaged and successfully reset to original parameters.

Conclusion

RF or MW ablation of tumors in liver, kidney, bone and lung can be performed safely in patients with permanent intra-cardiac devices, but careful planning between radiology and cardiology is essential to avoid adverse outcomes.     

The control of lateral stability during rapid stepping reactions evoked by antero-posterior perturbation: does anticipatory control play a role?

Volitional step initiation invariably includes a medio-lateral anticipatory postural adjustment (ML APA), which causes the center of mass (COM) to be propelled toward the stance-limb side prior to the lifting of the swing foot. The present study examined whether this type of anticipatory control plays a functional role in maintaining lateral stability during the rapid compensatory stepping reactions that are evoked when whole-body stability is challenged by unpredictable perturbation. Forward and backward stepping reactions were evaluated in five healthy young adults (ages 22–28) under three task conditions: (1) unconstrained compensatory stepping evoked by platform translation (no specific instructions), (2) constrained compensatory stepping cued by platform translation (prior instruction to step rapidly), and (3) rapid voluntary stepping to a light cue. ML APAs occurred during 70% of perturbation reactions but were too small and brief to have a substantive influence on the lateral movement of the COM occurring during leg lift or swing phase. In contrast, during the light-cued stepping, the ML APA propelled the COM toward the stance-limb side prior to the lifting of the swing limb, and effectively reduced the tendency of the COM to fall toward the swing-limb side during the execution of the step. It is proposed that the presence of an ML APA during compensatory stepping may represent an attempt to preplan a stereotypical stepping response, but that the ability to fully express the anticipatory phase is disrupted by the need to react rapidly to the unpredictable antero-posterior instability imposed by the perturbation. The results suggest that anticipatory control is not the primary mechanism by which the central nervous system deals with the lateral instability arising during rapid compensatory stepping reactions evoked by large, unpredictable antero-posterior perturbation.     

Percutaneous radiofrequency ablation of pulmonary tumors—Is there a difference between treatment under general anaesthesia and under conscious sedation?

OBJECTIVE: This retrospective study aimed to compare feasibility, complication rate and local tumor control after radiofrequency ablation (RFA) of pulmonary tumors under conscious analgo-sedation (AS) versus general anaesthesia (GA). MATERIALS AND METHODS: Within 36 months 21 patients had RFA (36 tumors, 26 treatment sessions). One patient suffered from NSCLC, 20 had metastases (breast (8/20), colorectal (6/20), renal cell (2/20), pharyngeal carcinoma (1/20), malignant melanoma (3/20)). Patients were no surgical candidates due to underlying comorbidities. Eleven of 26 treatments were performed under GA, while in 15 of 26 treatments AS was used. Follow-up was scheduled 24 h, 6 weeks, 3 months, 6 months and then every 6 months after treatment. RESULTS: RFA was feasible in all treatments under GA, while under AS targeting of the lesion was not possible in 2/15. Six adverse events occurred in the GA group (three major, three minor), while seven complications happened in the AS group (three major, four minor) (p=0.57). During follow-up of 3-36 months local recurrence was detected in 3 of 21 tumors in the GA group and in 2 of 15 tumors in the AS group (p=0.79). DISCUSSION: Hospitalization, complication rates and types, and the rate of local tumor control did not differ substantially among both groups. Furthermore, there was no significant difference in technical success and feasibility. CONCLUSION: RFA of pulmonary tumors under GA or AS did not result in different tumor control and complication rates, respectively. Therefore, AS should be used except in anxious or agitated patients.     

Radiofrequency ablation of lung malignancies: where do we stand?

Percutaneous radiofrequency (RF) ablation is a minimally invasive technique used to treat solid tumors. Because of its ability to produce large volumes of coagulation necrosis in a controlled fashion, this technique has gained acceptance as a viable therapeutic option for unresectable liver malignancies. Recently, investigation has been focused on the clinical application of RF ablation in the treatment of lung malignancies. In theory, lung tumors are well suited to RF ablation because the surrounding air in adjacent normal parenchyma provides an insulating effect, thus facilitating energy concentration within the tumor tissue. Experimental studies in rabbits have confirmed that lung RF ablation can be safely and effectively performed via a percutaneous, transthoracic approach, and have prompted the start of clinical investigation. Pilot clinical studies have shown that RF ablation enables successful treatment of relatively small lung malignancies with a high rate of complete response and acceptable morbidity, and have suggested that the technique could represent a viable alternate or complementary treatment method for patients with non-small cell lung cancer or lung metastases of favorable histotypes who are not candidates for surgical resection. This article gives an overview of lung RF ablation, discussing experimental animal findings, rationale for clinical application, technique and methodology, clinical results, and complications.