Radiofrequency ablation in the management of liver tumours.
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Catheter Ablation↗
Biomedical subjects
A R Gillams
Publications and source records attributed to A R Gillams.
Radiofrequency ablation extends the scope of surgery in colorectal liver metastases.
AIMS: To assess outcome in patients treated by a multidisciplinary team, with a combination of liver resection and RF ablation. METHODS: Sixteen unselected patients (f=9; m=7) with colorectal liver metastases who were not suitable for surgery alone, were treated as follows: six had RF ablation at open laparotomy, three patients had synchronous ablation and resection while seven patients had RF ablation after liver resection. Standard liver resection techniques were used. RF was performed using internally cooled, single or cluster electrodes with a high power (200 W) generator. All patients were followed with regular contrast enhanced CT and survival noted. RESULTS: A total of 27 tumours with diameters 1.2-10 cm were treated. Two minor complications were recorded. 2/6 (33%) who had intraoperative RF had incomplete ablation due to large tumour size (6 and 10 cm respectively). Further RF ablation sessions were carried out successfully. 11/16 (69%) are alive at 2 years of whom 7 (44%) have no evidence of residual or recurrent liver disease. CONCLUSION: In our study, RF ablation extends the therapeutic envelope, is an effective local treatment of liver metastases and improves life expectancy.
Aged↗
Non-invasive quantification of pancreatic exocrine function using secretin-stimulated MRCP.
Our objective was to quantify water volume using magnetic resonance cholangiopancreatography (MRCP) sequences and apply this to secretin-stimulated studies with the aim of quantifying pancreatic exocrine function. A commercially available single-shot MRCP sequence was used in conjunction with a body phased-array coil and a 1.5-T MR system. Signal intensity was measured in samples of water, pancreatic, duodenal juice, and secretin-stimulated pancreatic juice. A water phantom was made and MR calculated volumes compared with known water volumes within the phantom. Changes in small intestinal volume in response to secretin were measured in a group of 11 patients with no evidence of pancreatic disease. Changes in water volume were plotted over time. The pancreatic duct diameter before and after secretin was noted and filling defects were sought. All patients also underwent an axial breath-hold T1-weighted gradient-echo sequence and the pancreatic parenchyma was evaluated for size and signal intensity. There was no difference in the signal intensity of the different juice samples. There was excellent correlation between known and calculated MRCP volumes (chi(2)=0.99). All patients demonstrated normal duct morphology on MRCP and normal pancreatic parenchyma on T1-weighted imaging. The mean flow rate in the patient population was 8.1+/-2.5 ml/s over a median of 7 min (range 5-9 min). The MRCP sequence can be used to measure water volume. Sequential MRCP measurements following secretin permitted calculation of volume change and flow rate. This should prove useful as an indicator of pancreatic exocrine function.
Adolescent↗
Comparison of B-mode and conventional colour/power Doppler ultrasound, contrast-enhanced Doppler ultrasound and spiral CT in the diagnosis of focal lesions of the liver: Results of a multicentre study.
AIM: In patients with lesions of the liver we compared diagnoses based on different methods of ultrasound as well as spiral CT with the final diagnosis reached at the time of the patient's discharge from hospital. METHOD: From records of a prospective multicentre study including 90 liver lesions investigated with B-mode baseline and conventional colour/power Doppler ultrasound, contrast-enhanced colour/power Doppler ultrasound and spiral-CT, we evaluated only those where diagnoses for all modalities were available, and where the diagnosis at discharge comprising all clinical, laboratory and imaging data as well as histologic proof was at least "highly probable". RESULTS: 60 lesions met the inclusion criteria. 20 lesions were ultimately diagnosed as benign, and 40 as malignant. With respect to the diagnosis of malignancy, sensitivity was 92.5 % (37/40) with B-mode and unenhanced conventional colour/power Doppler US ultrasound, 97.5 % (39/40) with contrast-enhanced colour/ power Doppler ultrasound, and 100 % with CT; the corresponding specificities were 65 % (13/20), 85 % (17/20) and 80 % (16/20). 4 of 7 false positive, and 2 of 3 false negative results in the unenhanced technique were diagnosed correctly with contrast-enhanced Doppler ultrasound. CONCLUSION: Compared to conventional ultrasound, contrast-enhanced Doppler ultrasound improved the diagnostic accuracy in 10 % of the cases. Its accuracy in our study was equal to that of CT.
Contrast Media↗
Spiral CT pneumocolon: applications, status and limitations.
CT pneumocolon is a promising new technique in the diagnosis and management of colon pathology. CT pneumocolon can detect (sensitivity >95%) and stage (accuracy 79%) colorectal cancer and is very accurate in the differentiation of malignant from benign colonic pathologies. It has excellent detection rates for polyps >10 mm in diameter. Several studies using 3D virtual colonoscopy have already proven its high sensitivity and specificity in polyp detection making this technique robust as a screening tool. The combined results for virtual colonoscopy, from all centres, show a sensitivity of >85% in the detection of polyps 10 mm or greater in size, 70-80% for 5-9 mm polyps and an overall specificity of 90%. CT pneumocolon is a safe, non-invasive and cost-effective method for detecting colonic carcinomas and adenomas and correctly identifying which patients need further colonoscopy. The technique is quick, well tolerated and non-operator dependent. It can also image the proximal colon when distal stenoses prevent endoscopic and barium examination. CT pneumocolon is able to identify the features and complications of inflammatory bowel disease. Further research is warranted to fully assess its impact in terms of a screening tool, acceptability, availability and cost benefit.
Air↗
Neo-adjuvant therapy improves resectability rates for colorectal liver metastases.
PURPOSE: Liver resection improves survival in selected patients with colorectal liver metastases. However, the majority of patients with colorectal liver metastases have inoperable disease at presentation. Neo-adjuvant therapy (systemic or regional chemotherapy and interstitial laser therapy) used singly or in combination may convert a selected group of patients with irresectable liver metastases into an operable state. PATIENTS AND METHODS: We report a series of patients with initially inoperable multiple colorectal liver metastases who became operable after neo-adjuvant therapy. Operability was defined as unilateral disease limited to the liver. Twelve patients (7 female, 5 male, median age 57 years, range 38-69 years) with multiple inoperable colorectal liver metastases (8 synchronous, 4 metachronous) were initially treated with systemic chemotherapy (n = 7), hepatic arterial chemotherapy (n = 2) and chemotherapy plus interstitial laser therapy (n = 3). RESULTS: In all cases, a significant response was achieved which enabled subsequent liver resection to be undertaken. There was only one postoperative complication (8%) and no peri-operative deaths. 3 patients were operated on within the last 12 months and are still alive. Of the remainder, 1 died within 1 year with recurrent disease. The remaining patients have a median survival of 2.5 years, range 1.39-4 years. CONCLUSIONS: These results are similar to those reported for patients undergoing resection for operable metastases without neo-adjuvant therapy. Aggressive multimodality treatment of colorectal liver metastases in specialised centres may improve the resectability rates and survival in a selected group of patients.
Adult↗
Survival after percutaneous, image-guided, thermal ablation of hepatic metastases from colorectal cancer.
PURPOSE: One-year, two-year, three-year, and four-year survival rates and median survival time for patients with inoperable liver metastases from colorectal cancer is 32, 10, and 3 percent and 7.4 to 11 months, respectively. Systemic chemotherapy produces a modest improvement to 48, 21, and 3 percent and 12 months, respectively. Regional chemotherapy produces a further improvement to 64, 25, and 5 percent and 15 to 17 months, respectively. For those with operable disease, hepatic resection survival rates are 90, 62, 48, and 40 percent, respectively, and survival time is 33 months. Thermal ablation is effective in producing necrosis in liver metastases. We report the impact on survival in 69 patients treated from 1993 to 1997, with follow-up to 1998. METHODS: Sixty-nine patients, 50 male, mean age 60 (range, 33-87) years were treated. Liver resection was not feasible because of disease extent in the liver, extrahepatic disease or concurrent medical conditions. The average number of liver metastases was 2.9 (range, 1-16), the mean maximal diameter was 3.9 (range, 1-8) cm, and the mean initial total liver tumor volume was 47 (range, 1-371) ml. Eighteen (26 percent) had undergone previous hepatic resection. Sixty-two of 67 (93 percent) received chemotherapy at some stage. Twenty (29 percent) had extrahepatic disease. RESULTS: One-year, two-year, three-year, and four-year survival rates and median survival time from liver metastasis diagnosis was 90, 60, 34, and 22 percent and 27 months, respectively. Forty of 69 (58 percent) developed new liver metastases, and 23 of 69 (33 percent) developed new extrahepatic disease. Of a subgroup of 24 patients with less than four metastases, <5 cm diameter, treated after January 1995, the median survival time was 33 months from first thermal ablation vs. 15 months for the remainder (P = 0.0004). Major morbidity occurred in 3.2 percent, minor morbidity occurred in 12 percent, and there was one periprocedural death. CONCLUSIONS: Thermal ablation therapy improves survival in patients with inoperable but limited liver metastases. This is an improvement on the natural history of the disease and published chemotherapy results. Recent and ongoing technical refinements, not reflected in these results, are expected to further improve survival.
Adult↗
Treatment of recurrent colorectal liver metastases by interstitial laser photocoagulation.
BACKGROUND: Hepatic resection improves survival in selected patients with colorectal liver metastases. The treatment of recurrent hepatic metastases after resection is controversial. Interstitial laser photocoagulation, performed under local anaesthesia, offers a minimally invasive option to repeat resection. The first series of patients with recurrent colorectal liver metastases treated with photo- coagulation is reported. METHODS: Nineteen patients (five women and 14 men, median age 57 (range 44-71) years) who developed recurrent colorectal liver metastases after hepatectomy (five with bilateral disease) were treated with photocoagulation between 1993 and 1997. Fifteen patients also received chemotherapy (14 systemic, one hepatic arterial) before photocoagulation. RESULTS: There were no major complications or deaths related to the treatment. Six patients developed minor complications related to the procedure but did not require any form of intervention. Median survival from commencement of photocoagulation was 16 (range 4-36) months. CONCLUSION: Photocoagulation is a safe, minimally invasive therapy that may be used as an adjunct to chemotherapy and repeat resection in the treatment of recurrent colorectal liver metastases, and may lead to improved survival.
Adult↗
Colorectal liver metastases: alternatives to resection.
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Catheter Ablation↗
MRA of the intracranial circulation in asymptomatic patients with sickle cell disease.
BACKGROUND: MR angiography (MRA) provides a mechanism for non-invasively studying blood flow, thus providing a new opportunity to study the intracranial circulation in asymptomatic sickle cell disease (SCD) patients. Although conventional angiography is the gold standard for the depiction of vascular anatomy, this is too invasive for an asymptomatic population. OBJECTIVE: To establish the range of appearances in asymptomatic SCD patients and to correlate brain MRI results (either sub-clinical abnormalities or normal brain parenchyma) with the MRA findings. MATERIALS AND METHODS: Brain MRI and MRA of the intracranial circulation was performed on 22 patients (13 male and 9 female, median age 7.5 years, range 1.3-20 years). Fourteen were homozygous SS and eight were SC. The median haematocrit at the time of MRI was 25.9 (range 13.8-33.3). RESULTS: On MR imaging, four patients had infarcts in eight vascular territories (six anterior and two posterior). In 3/4 of anterior vascular territories with infarction, long ( >/= 6 mm) segments of abnormal signal were seen at the internal carotid artery bifurcation with associated reduced distal flow. Short focal areas of abnormal signal were commonly seen where vessels branched, bifurcated or curved and were not associated with infarcts. These areas probably represent turbulence-related dephasing secondary to high velocity flow found in SCD. CONCLUSION: Long segments ( >/= 6 mm) of abnormal signal with reduced distal flow correlated with sub-clinical infarction.
Adolescent↗
Helical CT pneumocolon to assess colonic tumors: radiologic-pathologic correlation.
OBJECTIVE: The objective of this study was to determine the accuracy of helical CT pneumocolon in the staging of colonic carcinomas. SUBJECTS AND METHODS: Fifty-two patients (27 men, 25 women; age range, 40-88 years old; mean age, 67 years old) with known or strongly suspected colonic disorders underwent CT pneumocolon. After bowel cleansing, administration of smooth muscle relaxant, and rectal air insufflation, CT pneumocolon was performed with 5-mm collimation, 2.5-mm reconstruction interval, and a pitch of 1.5. Two contrast administration protocols were used. Twelve patients received 100 ml of i.v. contrast material that was injected at 3 ml/sec; scan delay was 45 sec. The other 40 patients received 150 ml of contrast material at 5 ml/sec; scan delay was 25 sec. Images were prospectively evaluated. All patients had pathologic confirmation: 46 patients had resections and six patients had endoscopic biopsies. RESULTS: Diagnostic images were obtained in 47 of 52 patients. In the 47 patients, there were 38 colonic carcinomas (one synchronous), nine diverticular strictures, eight polyps, one ischemic stricture, and one normal study. Thirty of 38 carcinomas were correctly staged by CT. Sensitivity and specificity for serosal infiltration were 100% (35/35 carcinomas) and 33% (one of three carcinomas), respectively; sensitivity and specificity for lymph node involvement were 56% (nine of 16 carcinomas) and 95% (21/22 carcinomas), respectively. Four polyps that were smaller than 5 mm in diameter were not revealed by CT. Twelve of 14 benign lesions were correctly diagnosed and two were believed to be malignant. No malignant lesion was misdiagnosed. CONCLUSION: CT pneumocolon gave an overall staging accuracy of 79% in 38 carcinomas.
Adult↗
Carotid MRA--what advantages do the turbo field-echo and 3D phase-contrast sequences offer?
Our purpose was to investigate some of the newer MR angiography (MRA) techniques for studying the carotid arteries. Forty-two arteries in seven asymptomatic, healthy volunteers were studied using five MRA sequences: two conventional time-of-flight sequences, 2D time-of-flight (2DTOF) and 3D time-of-flight (3DTOF); 2D and 3D magnetisation-prepared, segmented time-of-flight sequences (2DTFE and 3DTFE); and a 3D phase contrast angiography (3DPCA) sequence. A protocol that could be realistically employed in a routine clinical situation was chosen. 2DTOF had significantly (P < 0.05) better signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) than 2DTFE. 3DTOF demonstrated better SNR than 3DTFE but 3DTFE demonstrated better CNR than 3DTOF. 3DPCA provided maximal anatomical coverage. No one sequence provided optimal anatomical coverage, accurate demonstration of the carotid bulb and maximal SNR and CNR. The combination of 3DPCA and a 3D inflow sequence was best. 2DTOF sequences are useful when only one brief sequence is practicably feasible.
Adult↗
Fast spin echo vs conventional spin echo in cervical spine imaging.
The major attraction of fast-spin-echo (FSE) imaging is reduced acquisition time; however, careful review of the literature reveals many weaknesses: phase-encoded blurring, truncation artefact, bright fat signal, reduced magnetic susceptibility and increased motion artefact. Our aim was a prospective, blinded comparison of FSE and conventional spin echo (CSE) in the cervical spine. Both sequences were performed in 43 patients (19 males and 24 females; mean age 45 years, range 15-66 years). Twenty-eight patients were studied at 1.5 T and 15 at 0.5 T. Typical sequence parameters were: at 1.5 T, TR/TE 2000/90 CSE and 3000/120 FSE, and at 0.5 T, 2200/80 CSE and 2800/120 FSE. Time saved on the FSE was used to increase the matrix and the number of acquisitions. Two neuroradiologists evaluated the images for pathology, artefacts, disc signal intensity, thecal sac compression and image quality. Ten patients had cord lesions; 2 (20 %) were missed on CSE. In 4 of 10 patients with moderate/severe thecal sac compression, the degree of stenosis was apparently exaggerated on CSE. The mean degree of confidence for the CSE sequences was 1.8 and for the FSE 1.1, where 1 is optimal. For cervical spine imaging, FSE should be preferred to CSE.
Artifacts↗
Cerebral infarction in patients with AIDS.
PURPOSE: To establish the frequency, distribution, and pathogenesis of cerebral infarction as confirmed with MR imaging in a cohort of patients with acquired immunodeficiency syndrome (AIDS). METHODS: We reviewed all (71) abnormal cranial MR studies obtained at our institution in human immunodeficiency virus (HIV)-positive patients over a 2-year period and recorded the number and distribution of ischemic lesions, any associated abnormalities, and the MR angiographic findings, where available. Patients' charts were studied for relevant clinical data, biochemical and culture results, and potential etiologic factors. RESULTS: Twenty-two infarcts were seen in 13 of the 71 patients. Of these 22, the basal ganglia area was affected in 15, the middle cerebral artery territory in two, and the vertebrobasilar territory in five. Five patients had concomitant evidence of infection, six others used cocaine or were intravenous drug abusers. MR angiography was performed in eight patients; two of these had multiple lesions consistent with vasculitis, two had isolated lesions that corresponded with their parenchymal infarct, and four had normal findings. CONCLUSIONS: The frequency of infarction was 18%, higher than previously reported. The pathogenesis of infarction was multifactorial. Underlying infectious causes were identified in 39% of patients. Two patients had an idiopathic vasculitis.
AIDS Dementia Complex↗
MR appearances of the temporal evolution and resolution of infectious spondylitis.
OBJECTIVE: We undertook this study to document the MR appearances of evolving or resolving infectious spondylitis. MATERIALS AND METHODS: A retrospective review was carried out of all patients with infectious spondylitis who had undergone MR imaging from 1991-1993 at Boston University Hospital and Boston City Hospital Imaging Foundation. The study population consisted of 25 patients (seven females and 18 males). There was a bimodal age distribution with peaks at 34 and 59 years old (age range, 25-81 years old). The causative organism was isolated in 20. Sixteen had Staphylococcus aureus, two had mycobacterium tuberculosis, and two had gram-negative bacilli. Follow-up MR imaging was performed in 20. Nine had two studies, three had three, five had four, two had five, and one had six. The median length of follow-up was 8 weeks (range, 2-104 weeks). Follow-up MR appearances were correlated with clinical outcome. RESULTS: Early imaging revealed atypical appearances. Fourteen of 20 (70%) improved; the first sign of response to treatment was a reduction in the inflammatory soft tissue (8/14, 57%). Changes in the bones or discs concurrently progressed in six of eight patients (75%) including involvement of a new disc level in four (50%). A definitive sign of healing was a peripheral rim of high T1 signal in bone (5/14, 36%). Gadolinium enhancement persisted long after resolution of changes in the soft tissues, for up to a median of 17.5 weeks (range, 8-80 weeks). A subgroup of six IV drug users showed unique radiologic features. CONCLUSION: The early appearances of infectious spondylitis may be atypical. Resolution of soft-tissue change and fat deposition in the bone marrow are reliable signs of healing. Bone or disc changes can progress despite clinical improvement. Gadolinium enhancement can increase and persist after symptom resolution.
AIDS-Related Opportunistic Infections↗
Recent developments in biliary tract imaging.
Recent imaging innovations and their role in patient management are discussed in this article. Additional topics include the place of endoscopic ultrasound (echoendoscopic and miniprobe), the impact of spiral CT, new developments in MR imaging, and a review of noninvasive cholangiography--CT scans and MR imaging.
Biliary Tract Diseases↗
Magnetization transfer contrast MR in lesions of the head and neck.
PURPOSE: To compare lesion-to-background contrast with and without magnetization transfer (MT) in lesions of the head and neck. METHODS: Twenty lesions (16 malignant, 4 benign) were evaluated in 17 patients (11 men, 6 women; mean age, 58 years; age range, 39-76 years). In 13 patients, MR imaging was performed at 0.1 T with continuous-wave, off-resonance MT; in 4 patients, MR imaging was performed at 1.5 T with on-resonance, binomial MT prepulses. Fifteen sequences were conducted before the administration of gadopentetate dimeglumine; 13 were conducted after the administration of that contrast material. The ratio of signal intensity with the MT pulses (Ms) to signal intensity without the MT pulses (Mo) was calculated, as were the lesion-to-background contrast and the contrast-to-noise ratios. RESULTS: Ms/Mo showed both wide variability and considerable overlap among different lesion types. Images from MT sequences showed better contrast than those from non-MT sequences in 23 of 28 lesions (12 of 15 before and 11 of 13 after the administration of contrast material). The mean contrast improvement percentages (+/- standard deviation) were 165.5% (+/- 58%) on unenhanced images and 186.6% (+/- 84.8%) on contrast-enhanced images. The mean improvements in contrast-to-noise ratios were 156% (+/- 60%) on unenhanced images and 171.6% (+/- 98.1%) on contrast-enhanced images. CONCLUSION: MT improved contrast between nodes or tumors showing an MT effect and background tissue (usually fat) not showing an MT effect. MT also improved contrast between contrast-enhanced neoplastic lesions and background tissue that showed an MT effect.
Adult↗
Percutaneous cholecystolithotomy: is gall stone recurrence inevitable?
Using radiological interventional techniques the gall bladder can be cleared of stones with a high success rate. As with any treatment option that leaves the gall bladder in situ there is an accompanying risk of stone recurrence, which is currently unknown for the radiological method. One hundred patients were studied prospectively to determine the recurrence rate of stones and clinical outcome after successful percutaneous cholecystolithotomy. Follow up included both clinical assessment and ultrasound examination at 3, 6, and 12 months and then annual intervals thereafter. The overall stone recurrence rate was 31% at a mean follow up of 26 months (range, 3-50 months). By actuarial life table analysis, the cumulative proportion of gall stone recurrence was 7, 19, 28, 35, and 44% at 6, 12, 24, 36, and 48 months respectively. Of the 31 patients with recurrent stones; 17 remain asymptomatic, seven have experienced biliary colic, two abdominal pain, three non-specific upper gastrointestinal symptoms, and two jaundice secondary to common duct stones. Thirteen of the stone free patients have remained symptomatic; six with abdominal pain and seven with nonspecific upper gastrointestinal symptoms. Eight patients have subsequently had a cholecystectomy. No significant difference was found between the sex of the patient or the number of stones before treatment and the stone recurrence rates. The cumulative stone recurrence rate was significantly less in the 56 patients who received adjuvant chemolitholysis (p < 0.05). These data show that stone recurrence after successful percutaneous cholecystolithotomy occurs in the minority, and is usually asymptomatic. It is concluded that the technique remains justified in the management of selected patients with gall stones.
Chenodeoxycholic Acid↗