Imaging of the thorax after percutaneous thermal ablation of lung malignancies.

Image-guided thermal ablation is a minimally invasive treatment option for patients with early stage non-small cell lung cancer or metastatic disease to the lungs. Percutaneous ablation treats malignant tumours in situ, which precludes histopathological evaluation of the ablated tumours. Imaging studies are used as surrogates to assess technical and clinical success. Although it is not universally accepted, a common protocol for surveillance imaging includes contrast-enhanced computed tomography (CT) at 1, 3, 6, 9, 12, 18, 24 months, and yearly thereafter. Integrated 2-[18F]-fluoro-2-deoxy-d-glucose positron-emission tomography (PET)/CT imaging is recommended at 3 and 12 months and when recurrent disease is suspected. There is a complex evolution of the ablation zone on CT and PET imaging studies. The zone of ablation, initially larger than the ablated tumour, undergoes gradual involution. In the process, it may cavitate and resemble a lung abscess. Different contrast-enhancement and radionuclide uptake patterns in and around the ablation zone may indicate a wide range of diagnostic possibilities from a normal physiological response to local progression. Ultimately, the zone of ablation may be replaced by a variety of findings including linear bands of density, pleural thickening, or residual necrotic tumour. Diagnostic and interventional radiologists interpreting post-ablation imaging studies must have a clear understanding of the ablation process and imaging findings on surveillance studies. Accurate and timely recognition of complications and/or local recurrence is necessary to guide further therapy. The purpose of this article is to review imaging protocols and salient imaging findings after thermal ablation of lung malignancies.

Embryonic origin of primary colon cancer predicts survival in patients undergoing ablation for colorectal liver metastases.

BACKGROUND: In patients with primary colorectal cancer (CRC) or unresectable metastatic CRC, midgut embryonic origin is associated with worse prognosis. The impact of embryonic origin on survival after ablation of colorectal liver metastases (CLM) is unclear. METHODS: We identified 74 patients with CLM who underwent percutaneous ablation during 2004-2015. Survival and recurrence after ablation of CLM from midgut origin (n = 18) and hindgut origin (n = 56) were analyzed. Prognostic value of embryonic origin was evaluated. RESULTS: Recurrence-free survival (RFS) and overall survival (OS) after percutaneous ablation were worse in patients from midgut origin (3-year RFS: 5.6% vs. 24%, P = 0.004; 3-year OS: 25% vs. 70%, P 0.001). In multivariable analysis, factors associated with worse OS were midgut origin (hazard ratio [HR] 4.87, 95% CI 2.14-10.9, P 0.001), multiple CLM (HR 2.35, 95% CI 1.02-5.39, P = 0.044), and RAS mutation (HR 2.78, 95% CI 1.25-6.36, P = 0.013). At a median follow-up of 25 months, 56 patients (76%) had developed recurrence, 16 (89%) with midgut origin and 40 (71%) with hindgut origin (P = 0.133). Recurrent disease was treated with local therapy in 20 patients (36%), 2 (13%) with midgut origin and 18 (45%) with hindgut origin (P = 0.022). CONCLUSION: Compared to CLM from hindgut origin tumors, CLM from midgut origin tumors were associated with worse survival after ablation, which was partly attributable to the fact that patients with hindgut origin were more frequently candidates for local therapy at recurrence.

Local tumour progression after percutaneous ablation of colorectal liver metastases according to RAS mutation status.

BACKGROUND: Percutaneous ablation is a common treatment for colorectal liver metastasis (CLM). However, the effect of rat sarcoma viral oncogene homologue (RAS) mutation on outcome after ablation of CLMs is unclear. METHODS: Patients who underwent image-guided percutaneous ablation of CLMs from 2004 to 2015 and had known RAS mutation status were analysed. Patients were evaluated for local tumour progression as observed on imaging of CLMs treated with ablation. Multivariable Cox regression analysis was performed to determine factors associated with local tumour progression-free survival. RESULTS: The study included 92 patients who underwent ablation of 137 CLMs. Thirty-six patients (39 per cent) had mutant RAS. Rates of local tumour progression were 14 per cent (8 of 56) for patients with wild-type RAS and 39 per cent (14 of 36) for patients with mutant RAS (P = 0·007). The actuarial 3-year local tumour progression-free survival rate after percutaneous ablation was worse in patients with mutant RAS than in those with wild-type RAS (35 versus 71 per cent respectively; P = 0·001). In multivariable analysis, negative predictors of local tumour progression-free survival were a minimum ablation margin of less than 5 mm (hazard ratio (HR) 2·48, 95 per cent c.i. 1·31 to 4·72; P = 0·006) and mutant RAS (HR 3·01, 1·60 to 5·77; P = 0·001). CONCLUSION: Mutant RAS is associated with an earlier and higher rate of local tumour progression in patients undergoing ablation of CLMs.

Ablative therapies in renal cell carcinoma.

We reviewed the use of ablative therapies in the management of renal cell carcinoma. We performed a PubMed search of the English language literature using the keywords "ablation" and "renal carcinoma." Pertinent articles specific to the technologic advancement of ablative therapy and clinical outcomes were selected for review. Intermediate-term oncologic outcomes of cryoablation and radiofrequency ablation are acceptable but are not quite as good as for surgical excision based nearly all on retrospective studies. No randomized studies have been performed comparing excisional and ablative therapies. Careful selection of patients and tumor characteristics results in improved outcomes. Diagnostic biopsy for tissue confirmation is mandatory and should even be considered post therapy after 6-12 months in patients with a concern about recurrence. Ablative therapies are associated with decreased morbidity, less severe complication rates, and excellent preservation of renal function in comparison with surgical excision. The majority of recurrences occur early, but long-term surveillance is required as delayed recurrences are also possible and the long-term oncologic efficacy is not yet established. Ablation can be delivered percutaneously or laparoscopically, and the superiority of one over the other remains controversial. The percutaneous approach is more cost effective and causes less perinephric desmoplasia. Nearly all data on ablation are retrospective and, with few exceptions, from single institutions. Ablative therapy is an appealing option for the management of small renal tumors shown to be renal cell carcinoma on biopsy in patients who are unsuitable candidates for surgical extirpation.

Percutaneous closure of a subclavian artery injury after inadvertent catheterization.

Life-threatening complications of subclavian central venous access are rare. Herein a case of inadvertent subclavian artery catheterization and subsequent percutaneous arterial repair with use of the Prostar XL suture-mediated closure device and temporary balloon tamponade is reported. This approach obviated a complex surgical intervention that would have required medial clavicle resection.

Trauma to the aorta and aortic arch branches.

Deceleration and crushing injuries of the chest may traumatize the thoracic aorta or its branches. Traumatic aortic rupture has received significant attention over the past 40 years, whereas the aortic arch branch injuries remain under-recognized. Despite the development of new imaging modalities, angiography remains the gold standard for evaluation of a patient with suspected thoracic arterial injury. Recently, computed tomography and transesophageal echocardiography have been used for serial examination of minimal aortic injuries that are treated conservatively. Medical treatment of the ruptured aorta, delayed surgical repair, and endoluminal deployment of stent-grafts are new developments that provide new options and pose new questions in the management of thoracic arterial injuries.

Colocolic intussusception caused by pneumatosis cystoides coli.

We report the case of a 29-year-old man with a long-standing history of abdominal pain related to an intermittent colocolic intussusception caused by pneumatosis cystoides coli. To our knowledge, only one similar case has been reported in the English-language literature.

Angiography in blunt thoracic aortic injury.

PURPOSE: Recent studies have suggested that transesophageal echocardiography (TEE) can be used as the primary imaging method in patients suspected of traumatic rupture of the thoracic aorta. A segment of the aorta and the aortic arch branches cannot be adequately evaluated in all patients by TEE. To assess the impact of these limitations of TEE, this retrospective study examined the aortographic features of traumatic aortic or great vessel injuries in a large number of patients. MATERIALS AND METHODS: We retrospectively reviewed clinical and imaging features of 89 patients with a history of blunt chest trauma and angiographic evidence of traumatic injury to the thoracic aorta or to its branches. RESULTS: Of these 89 patients, 72 had aortic rupture alone. One (1%) of these ruptures occurred at the distal ascending aorta, a potential blind spot for TEE. Seventeen patients (19%) had 24 injuries to the aortic arch branches: in 14 of these 17 patients, the aorta was intact, whereas three patients also had aortic rupture. Seventy percent of the injuries to the aortic arch branches were not suspected on physical examination. CONCLUSION: Twenty percent of patients in our retrospective series had traumatic involvement of aortic arch branches or the distal ascending aorta. These vascular injuries may be suboptimally assessed or overlooked if TEE is used as the sole imaging modality in the evaluation of patients with blunt chest trauma.