P Guest

Queen Elizabeth Hospital Birmingham, Birmingham, ENG, United Kingdom

Are you P Guest?

Claim your profile

Publications (13)31.01 Total impact

  • Article: A fatal complication following hybrid total arch replacement with supra-aortic artery translocation and endovascular stenting.
    [show abstract] [hide abstract]
    ABSTRACT: This case highlights the successful management of acute Type B dissection complicated by visceral malperfusion. Even though the procedure of hybrid supra-aortic translocation and endovascular stenting corrected the malperfusion, it is important for vigilant CT scan surveillance for the post operative complications which can occur with this procedure.
    European journal of vascular and endovascular surgery: the official journal of the European Society for Vascular Surgery 12/2007; 34(5):534-6. · 2.92 Impact Factor
  • Article: CT colonography: interpretative performance in a non-academic environment.
    [show abstract] [hide abstract]
    ABSTRACT: To investigate interpretative accuracy and reporting time for radiologists performing computed tomography (CT) colonography in day-to-day non-academic clinical practice. Thirteen radiologists from seven centres, who were reporting CT colonography in non-academic daily clinical practice, interpreted a dataset of 15 colonoscopically validated cases in a controlled environment. Ten cases had either a cancer or polyp >10mm; one case had a medium polyp and four were normal. Correct case categorization and interpretation times were compared using analysis of variance to aggregated results obtained from both experienced observers and observers recently trained using 50 cases, working in an academic environment. The effect of experience was determined using Spearman's rank correlation. Individual accuracy was highly variable, range 53% (95% CI 27-79%) to 93% (95% CI 68-100%). Mean accuracy overall was significantly inferior to experienced radiologists (mean 75 versus 88%, p=0.04) but not significantly different from recently trained radiologists (p=0.48). Interpretation time was not significantly different to experienced readers (mean 12.4 min versus 11.7, p=0.74), but shorter than recently trained radiologists (p=0.05). There was a significant, positive, linear correlation between prior experience and accuracy (p<0.001) with no plateau. Accuracy for sub-specialist radiologists working in a non-academic environment is, on average, equivalent to radiologists trained using 50 cases. However, there is wide variability in individual performance, which generally falls short of the average performance suggested by meta-analysis of published data. Experience improves accuracy, but alone is insufficient to determine competence.
    Clinical Radiology 05/2007; 62(5):424-9; discussion 430-1. · 1.95 Impact Factor
  • Article: An audit of fusion CT-PET in the management of colorectal liver metastases.
    [show abstract] [hide abstract]
    ABSTRACT: To assess the use of positron emission tomography combined with computerized tomography (CT-PET) with fluoro-18-2-deoxy-d-glucose ((18)F-FDG) to identify hyper-metabolic tumours, especially colorectal metastases (CRM). Patient particulars, diagnoses and clinical outcome for each patient were studied. Twenty-three patients underwent CT-PET, 10 males and 13 females, median age 59 (range 34-72). Fourteen patients presented with primary liver CRM and nine had undergone previous liver resections. Indications for CT-PET included; suspected extrahepatic disease in 13/23 patients, possible hepatic recurrence 5/23 and clinical suspicion in 8/23 patients. Seven patients had a major impact on their management. Unexpected (not seen on CT) findings in the CRM group included, 7/23 (30%) patients with extrahepatic disease, 3/23 with hepatic metastases, 8/23 suspected of having liver or distant metastases on CT had a negative study. A clinical decision, based on the CT-PET report, could be undertaken in 21/23 patients. CT-PET is useful in patients with CRM where conventional imaging presents dilemmas such as: assessment of suspected extrahepatic disease, recurrence in liver, patients with advanced or perforated initial tumours.
    European Journal of Surgical Oncology 07/2006; 32(5):564-7. · 2.50 Impact Factor
  • Article: Imaging the post-operative thoracic aorta: normal anatomy and pitfalls.
    [show abstract] [hide abstract]
    ABSTRACT: Following surgical repair or replacement of the thoracic aorta, interpretation of CT and MRI scans of the thorax can be confusing. It is important to be aware of the variety of appearances that can be encountered. There is usually a surgical explanation and close collaboration with surgical colleagues is required. An appreciation of the normal post-operative appearances allows recognition of the abnormal. Potential pitfalls in interpretation are discussed.
    British Journal of Radiology 01/2002; 74(888):1150-8. · 1.31 Impact Factor
  • Source
    Article: Clinical and patho-anatomical factors affecting expansion of thoracic aortic aneurysms.
    [show abstract] [hide abstract]
    ABSTRACT: To examine the expansion of aneurysmal aortic segments (> or = 35 mm) and to assess the impact of clinical and patho-anatomical factors on aneurysm expansion. 87 consecutive patients (mean age 63.6 years, range 22-84 years) were studied using serial (six month intervals) computed tomographic or magnetic resonance imaging to monitor progression of thoracic aortic aneurysms. Aortic diameter was measured at seven predetermined segments and at the site of maximum aortic dilatation (MAX). 780 segment intervals were identified. The median overall aneurysm expansion rate was 1.43 mm/year. This increased exponentially with incremental aortic diameter (p < 0.01) and varied by anatomical segment (p < 0.05). The presence of intraluminal thrombus (p < 0.01) but not dissection or calcification was associated with accelerated growth. Univariate analysis identified thrombus (p < 0.001), previous stroke (p < 0.002), smoking (p < 0. 01), and peripheral vascular disease (p < 0.05) as factors associated with accelerated growth in MAX. Dissection, wall calcification, and history of hypertension did not affect expansion. beta Blocker treatment was not associated with protection. Multivariate analysis confirmed the positive effect of intraluminal thrombus and previous cerebral ischaemia, and the negative effect of previous aortic surgery on aneurysm growth. These findings translated into a mathematical equation describing exponential aneurysm expansion. Aneurysmal thoracic aortic segments expand exponentially according to their initial size and their anatomical position within the aorta. The presence of intraluminal thrombus, atherosclerosis, and smoking history is associated with accelerated growth and may identify a high risk patient group for close surveillance.
    Heart (British Cardiac Society) 09/2000; 84(3):277-83. · 4.22 Impact Factor
  • Article: Percutaneous image-guided biopsy of lung nodules in the assessment of disease activity in Wegener's granulomatosis.
    [show abstract] [hide abstract]
    ABSTRACT: In patients with known Wegener's granulomatosis (WG) and persistent chest radiographic abnormalities, assessment for disease activity is often difficult, prompting the need for histological diagnosis to determine appropriate treatment. Here we report the use of automated image-guided core needle biopsy of pulmonary lesions for the assessment of disease activity in WG, rather than for primary diagnosis. Image-guided percutaneous core needle biopsy was performed on five occasions in four patients with thoracic WG and persistent radiographic abnormalities of the chest. Clinical features, indication for biopsy, radiographic abnormalities and pathological findings were recorded. Adequate pathological specimens were obtained, allowing exclusion of infection and tumour. Active chronic inflammation with or without vasculitis was demonstrated in each case, indicating the need for further immunosuppressive therapy. A small pneumothorax following biopsy in one case required no treatment. Follow-up chest imaging revealed a reduction in the extent of thoracic disease following therapy in all cases. The safety and diagnostic accuracy of image-guided core biopsy of thoracic lesions makes it a useful tool in the assessment of disease activity in WG patients with persistent chest radiographic lesions.
    Rheumatology 08/2000; 39(7):776-82. · 4.06 Impact Factor
  • Article: Image-guided automated needle biopsy of 106 thoracic lesions: a retrospective review of diagnostic accuracy and complication rates.
    S Connor, J Dyer, P Guest
    [show abstract] [hide abstract]
    ABSTRACT: We reviewed the diagnostic accuracy and complication rates of transthoracic needle biopsy (TNB) with an automated 18-gauge core biopsy needle and gun, using either fluoroscopic or CT guidance. One hundred six lesions were biopsied in 103 patients between 1992 and 1998. Hard-copy images, imaging reports, pathology reports and clinical notes were reviewed. In 3 patients it was not possible to establish the lesion as either malignant or benign from the available follow-up, so these were removed from the analysis of diagnostic accuracy. Adequate samples for histological diagnosis were obtained in 104 of 106 (98%) biopsies. There were 75 of 85 (88%) true-positive core biopsies for malignant lesions and a specific cell type was identified in 70 of 85 (82%) cases. A specific histological diagnosis was obtained in 12 of 18 (66%) biopsies. There was a 19% rate of pneumothorax with only 2.4% requiring drainage. Minor haemoptysis occurred in 3.8% of procedures. The TNB technique with an automated core biopsy needle provides a high level of diagnostic accuracy, effectively distinguishes cell type in malignancy and provides a definite diagnosis in benign disease more frequently than fine needle aspiration (FNA). There is no increased complication rate compared with FNA.
    European Radiology 02/2000; 10(3):490-4. · 3.22 Impact Factor
  • Source
    Article: Conversion of multiple solid testicular teratoma metastases to fatty and cystic liver masses following chemotherapy: CT evidence of "maturation".
    S Connor, P Guest
    [show abstract] [hide abstract]
    ABSTRACT: Testicular germ cell tumour metastases may undergo "retroconversion" to mature differentiated teratoma following chemotherapy or irradiation. We report a patient with testicular germ cell liver metastases in whom computed tomography (CT) scans following chemotherapy demonstrated a reduction in CT attenuation of the liver lesions to that of cystic and fatty density. This is believed to represent CT evidence of liver metastasis "retroconversion", which offers the potential for non-invasive monitoring of histological progression.
    British Journal of Radiology 12/1999; 72(863):1114-6. · 1.31 Impact Factor
  • Article: Reproducibility of thoracic aortic diameter measurement using computed tomographic scans.
    [show abstract] [hide abstract]
    ABSTRACT: Decisions to recommend elective surgical repair of thoracic aortic aneurysms (TAA) may be based on size or expansion rate, which are used as indices of the risk of rupture. Measurement error may thus affect clinical decision-making. In order to evaluate the reproducibility of aortic diameter measurements of TAA, we assessed departmental inter- and intra-observer variability of measurement of pre-selected computed tomographic scan images of aneurysmal segments of the thoracic aorta. We compared measurements of minimum aortic diameter made by four observers in 50 pre-selected scans and at different times by two observers using a calliper method and a measurement tool within the scan. Differences in measured dimension were analysed using Wilcoxon's signed ranks test and the repeatability assessed using the method of Bland and Altman. There were no significant inter-observer differences among three observers but there were significant differences between another observer and two other observers (P < 0.05). No significant intra-observer differences existed. The best intra-observer repeatability was 2.25 while the worst inter-observer repeatability was 4.37. The mean and maximum difference in measurement were +/-0.88 mm and +/-8.0 mm, respectively. Variability of measurement increased with aortic diameter. Calliper measurement of TAA is an acceptable measurement method for surveillance of TAA but appears most accurate with a single observer. Increasing error is seen with increasing diameter which may compound error in estimation of expansion rate. Standardisation of technique is advisable for multiple observers and aortic units should adopt quality assurance protocols to minimise error.
    European Journal of Cardio-Thoracic Surgery 08/1999; 16(1):59-62. · 2.55 Impact Factor
  • Article: Homograft replacement of thoraco-abdominal aorta for a leaking mycotic aneurysm.
    D Pagano, P Guest, R S Bonser
    [show abstract] [hide abstract]
    ABSTRACT: We report the case of a 67-year-old, diabetic patient who underwent antibiotic-preserved homograft replacement of a thoraco-abdominal segment of the aorta for leaking mycotic aneurysm. This was successful in eradicating the sepsis and no graft complication had occurred at (18 months). Follow-up with computed tomography (CT) scanning.
    European Journal of Cardio-Thoracic Surgery 02/1996; 10(5):383-5. · 2.55 Impact Factor
  • Article: Interventional sialography using digital imaging.
    T Buckenham, P Guest
    [show abstract] [hide abstract]
    ABSTRACT: We review our results in treating 5 patients with parotid duct pathology (3 stenoses, 2 calculi), using digital subtraction imaging for sialography, and standard interventional techniques using balloon catheters. Good technical results were achieved in all 5 patients. We describe our techniques and how they were modified to overcome various difficulties.
    Australasian Radiology 03/1993; 37(1):76-9. · 0.51 Impact Factor
  • Article: Thrombolysis of the occluded prosthetic graft with tissue-type plasminogen activator--technique, results and problems in 23 patients.
    P Guest, T Buckenham
    [show abstract] [hide abstract]
    ABSTRACT: Over a 12 month period all patients but one presenting to our hospital with occluded prosthetic grafts were treated by thrombolysis using local pulsed administration of tissue-type plasminogen activator (t-PA). There were 30 interventions in 23 patients but in one patient no thrombolytic was given after aspiration of pus from the graft. Thrombolysis was attempted in the remaining 29 procedures. 22/29 (76%) of these procedures were performed by direct puncture and catheterization of the occluded graft and in a further six (21%) access was from a non-occluded femoral artery or graft. In one case the graft was accessed surgically. Supplementary angioplasties were performed in 15 cases (52%). Complications requiring surgery occurred in four (14%) with a further seven minor complications. There were no deaths. A lower rate of complications occurred in the grafts entered by direct puncture. Thrombolysis was achieved in all but one case taking an average of only 2.5 h but was only maintained beyond the end of the procedure in 21/29 (72%). An underlying cause for occlusion was identified and treated where possible, e.g. haematological or clotting abnormalities or inflow or outflow stenoses. There was a high rate of reocclusion but with repeat procedures when necessary patency was maintained in 10/22 patients (45%) on follow-up at 1 to 12 months. The best results were obtained with lysis of occluded femoro-femoral crossover grafts.
    Clinical Radiology 01/1993; 46(6):381-6. · 1.95 Impact Factor
  • Article: Non-operative removal of a parotid duct stone with a balloon angioplasty catheter.
    P Guest, A Maciag, T Buckenham
    [show abstract] [hide abstract]
    ABSTRACT: We illustrate a rapid and simple method for removal of a stone from the parotid duct using a balloon angioplasty catheter and digital subtraction imaging. No anaesthesia or surgical intervention is necessary.
    British Journal of Oral and Maxillofacial Surgery 07/1992; 30(3):197-8. · 1.95 Impact Factor