Government reform of the National Health Service: implications for radiologists and diagnostic services.

Demand for radiology services within the National Health Service (NHS) continues unabated and current NHS operations cannot keep up with demand. Therefore, to meet this demand, the government has decided to outsource a significant number of investigations to the independent sector and will actively promote patient referrals to the new government sponsored Treatment Centres as they become available. This presents opportunities to patients, but threatens existing public sector providers (including doctors) as competition for radiology services may result in both loss of patient referrals and revenue to these providers. This article is a personal opinion and will focus on the current challenges facing the provision of radiology services in the NHS. I will suggest the possible negative outcomes for providers (NHS hospitals and staff alike) and will offer strategies, tactics and tools that can be employed to counter the threat to their existing services.

Tumour size measurement in an oncology clinical trial: comparison between off-site and on-site measurements.

AIM: To evaluate the degree of variability between lesion measurements obtained by a single observer compared with multiple observers, and in selected cases evaluate which of the two measurements more accurately represented the lesion size. MATERIALS AND METHODS: In this study we compared the performance of a single off-site observer to multiple on-site observers during measurement of 300 abdominal and thoracic lesions. Lesion measurements that were larger than 1cm(2), differed by more than 50%, but by less than 100%, were compared by a single adjudicator, who was blinded to the measurement source (n=46). RESULTS: Measurements of the 300 lesions differed by an average of 109% (SD 251%). Of 266 lesions larger than 1cm(2), results of the single observer compared with multiple observers differed by more than 10% for 249 lesions, more than 30% for 169 lesions, more than 50% for 126 lesions, and more than 100% for 66 lesions. Forty-six lesions were compared by the adjudicator. The adjudicator selected the measurement of the single observer for 37 lesions (80.4%), and the measurement determined by one of the multiple observers for nine lesions (19.6%; p=0.00002). CONCLUSION: Measurement of lesion size by a single observer compared with multiple observers reveals a high degree of variability. An adjudicator selected the measurement of the single observer more frequently than that of multiple observers, with statistical significance. These findings suggest that studies designed to quantify imaging features should limit the number of observers.

State-of-the-art adrenal imaging.

The adrenal gland is a common site of disease, and detection of adrenal masses has increased with the expanding use of cross-sectional imaging. Radiology is playing a critical role in not only the detection of adrenal abnormalities but in characterizing them as benign or malignant. The purpose of the article is to illustrate and describe the appropriate radiologic work-up for diseases affecting the adrenal gland. The work-up of a suspected hyperfunctioning adrenal mass (pheochromocytoma and aldosteronoma) should start with appropriate biochemical screening tests followed by thin-collimation computed tomography (CT). If results of CT are not diagnostic, magnetic resonance (MR) and nuclear medicine imaging examinations should be performed. CT has become the study of choice to differentiate a benign adenoma from a metastasis in the oncology patient. If the attenuation of the adrenal gland is over 10 HU at nonenhanced CT, contrast material-enhanced CT should be performed and washout calculated. Over 50% washout of contrast material on a 10-minute delayed CT scan is diagnostic of an adenoma. For adrenal lesions that are indeterminate at CT in the oncology patient, chemical shift MR imaging or adrenal biopsy should be performed. Certain features can be used by the radiologist to establish a definitive diagnosis for most adrenal masses (including carcinoma, infections, and hemorrhage) based on imaging findings alone.

Characterization of indeterminate (lipid-poor) adrenal masses: use of washout characteristics at contrast-enhanced CT.

PURPOSE: To determine whether computed tomographic (CT) scans and attenuation measurements on contrast material-enhanced and nonenhanced CT scans could be used to characterize adrenal masses, in particular, to characterize these lesions by using adrenal washout characteristics at contrast-enhanced CT. MATERIALS AND METHODS: Eighty-six patients (49 men, 37 women; age range, 29-86 years; mean age, 72 years) with 101 adrenal lesions depicted at contrast-enhanced CT underwent delayed (mean, 9 minutes) enhanced scanning. Seventy-eight patients also underwent nonenhanced CT. Mean diameter of the benign lesions was 2.1 cm (range, 1.0-4.2 cm); mean diameter of the malignant lesions was 2.3 cm (range, 1.0-4.1 cm). Region-of-interest measurements were obtained at nonenhanced, dynamic enhanced, and delayed enhanced CT and were used to calculate a relative percentage washout as follows: 1 - (Hounsfield unit measurement on delayed image / Hounsfield unit measurement on dynamic image) x 100%. RESULTS: Ninety-nine of 101 lesions were correctly characterized as benign or malignant with a relative percentage washout threshold of 50% on delayed scans; benign lesions demonstrated more than 50% washout; and malignant lesions, less than 50% washout. Two benign lesions demonstrating less than 50% washout were characterized as benign by using conventional CT. CONCLUSION: Calculation of relative percentage washout on dynamic and delayed enhanced CT scans may lead to a highly specific test for adrenal lesion characterization, reduce the need for, and possibly obviate, follow-up imaging or biopsy.

Dose reduction in gastrointestinal and genitourinary fluoroscopy: use of grid-controlled pulsed fluoroscopy.

OBJECTIVE: We evaluated the diagnostic accuracy of a grid-controlled fluoroscopy unit compared with a conventional continuous fluoroscopy unit for a variety of abdominal and pelvic fluoroscopic examinations. SUBJECTS AND METHODS: Seventy patients (29 men and 41 women; age range, 24-78 years) were enrolled in one of seven abdominal and pelvic fluoroscopic examinations, including upper gastrointestinal series (n = 20), barium enema (n = 10), voiding cystourethrogram (n = 10), percutaneous abdominal catheter tube injection (n = 10), hysterosalpingogram (n = 10), and percutaneous needle insertion and catheter placement (nephrostomy, percutaneous biliary drainage) (n = 10). Each patient underwent at least 10 sec of continuous fluoroscopy that was randomly and blindly compared with 10-sec periods of pulsed fluoroscopy at 15, 7.5, and 3.75 frames per second. A radiologist outside the examination room, unaware of the frame rate per second, evaluated the procedure in real time on a television monitor. The radiologist assessed image quality and diagnostic acceptability using a scoring system. Statistical analysis was performed using the paired Student's t test. RESULTS: For all procedures at all frame rates, we found no statistically significant superiority of one frame rate over another. For most procedures, the slower frame rates were considered equivalent to continuous fluoroscopy when the images were assessed for image quality and diagnostic confidence. CONCLUSION: Our findings suggest that most abdominal and pelvic fluoroscopic procedures can be performed at substantially lower frame rates than those used for continuous fluoroscopy; adopting this procedure may lead to substantial dose savings for the patient and the fluoroscopy operator.

Adenocarcinoma of the head of the pancreas: determination of surgical unresectability with thin-section pancreatic-phase helical CT.

OBJECTIVE: This study was conducted to evaluate newly introduced criteria for unresectability of pancreatic cancer with thin-section pancreatic-phase helical CT. MATERIALS AND METHODS: Twenty-five patients with adenocarcinoma in the head of the pancreas underwent thin-section pancreatic-phase helical CT. The major peripancreatic vessels were categorized on a scale of 1-4, according to the degree of circumferential involvement by tumor. The maximum diameters of the small peripancreatic veins--gastrocolic trunk, anterosuperior pancreaticoduodenal vein, and posterosuperior pancreaticoduodenal vein--were recorded. Findings on CT were compared with the results of surgery in each patient. RESULTS: Sixteen patients had surgically resectable tumors, and nine patients had surgically unresectable tumors. CT and surgical correlation was available for 98 major peripancreatic vessels; 85 were resectable and 13 were unresectable. Of category 1 vessels, 72 (97%) of 74 were resectable at surgery. Of category 2 vessels, 12 (71%) of 17 were resectable. One (50%) of two category 3 vessels and none (0%) of five category 4 vessels were resectable at surgery. CT showed a dilated gastrocolic trunk in two patients; one of these patients had a surgically resectable tumor, but the other patient had a surgically unresectable tumor. CONCLUSION: In patients with adenocarcinoma in the head of the pancreas, the degree of circumferential vessel involvement by tumor as shown by CT is useful in predicting which patients will have surgically unresectable tumors. A dilated gastrocolic trunk should not be used as an independent sign of surgical unresectability.

Pancreatic-phase versus portal vein-phase helical CT of the pancreas: optimal temporal window for evaluation of pancreatic adenocarcinoma.

OBJECTIVE: Our objective was to use helical CT to compare the enhancement attenuation values of pancreatic adenocarcinoma, adjacent normal pancreas, and critical vascular structures during the pancreatic phase and portal vein phase. SUBJECTS AND METHODS: Forty-one patients with pathologically proven pancreatic adenocarcinoma underwent dual-phase thin-section dynamic helical CT using a pancreatic-phase and portal vein-phase protocol. The scan delay after initiation of the contrast bolus was 40 sec for the pancreatic phase and 70 sec for the portal vein phase. Attenuation values after i.v. contrast administration were calculated during both phases of scanning for normal pancreas, pancreatic tumor, celiac axis, superior mesenteric artery, superior mesenteric vein, splenic vein, and portal vein. Quantitative values were assessed using regions of interest. RESULTS: Mean differences of enhancement between tumor and normal pancreas were significantly greater in the pancreatic phase (57 H) than the portal vein phase (35 H) (p = .0001). Enhancement values of all the critical vascular structures were also significantly greater in the pancreatic phase than the portal vein phase (p < .001). CONCLUSION: With dynamic thin-section helical CT, pancreatic-phase scanning provides greater differences in contrast enhancement between normal pancreas and pancreatic tumor and between pancreatic tumors and surrounding critical vascular structures than does portal vein-phase scanning.

The incidental nonhyperfunctioning adrenal mass: an imaging algorithm for characterization.

Nonhyperfunctioning adrenal lesions such as cysts, myelolipomas, adrenal haemorrhage, adenoma and metastases are described. Definitive imaging features that help characterize adrenal cysts, myelolipomas and adrenal haemorrhage are illustrated and the differentiation of benign from malignant adrenal lesions using an algorithmic approach based on lipid sensitive imaging is provided.

Characterization of adrenal masses using unenhanced CT: an analysis of the CT literature.

OBJECTIVE: Unenhanced CT scanning can reliably characterize incidentally detected adrenal masses when observers use density measurements of the adrenal gland. However, controversy exists as to the optimal density threshold required to differentiate benign from malignant lesions. This study attempts to establish a consensus by performing a pooled analysis of data found in the CT literature. MATERIALS AND METHODS: Ten CT reports were analyzed, from which individual adrenal lesion density measurements were obtained for 495 adrenal lesions (272 benign lesions and 223 malignant lesions). Threshold analysis generated a range of sensitivities and specificities for lesion characterization at different density thresholds. RESULTS: Sensitivity for characterizing a lesion as benign ranged from 47% at a threshold of 2 H to 88% at a threshold of 20 H. Similarly, specificity varied from 100% at a threshold of 2 H to 84% at a threshold of 20 H. CONCLUSION: The attempt to be absolutely certain that an adrenal lesion is benign may lead to an unacceptably low sensitivity for lesion characterization. The threshold chosen will depend on the patient population and the cost-benefit approach to patient care.

Asymptomatic hydropneumothorax after therapeutic thoracentesis for malignant pleural effusions.

OBJECTIVE: The purpose of this study was to document in a historical cohort the incidence and clinical observations of pneumothorax ex vacuo after therapeutic thoracentesis for malignant pleural effusions in patients with underlying parenchymal lung disease. MATERIALS AND METHODS: Forty pneumothoraces resulted from 512 therapeutic thoracentesis performed for malignant pleural effusions over a 3-year period. Twenty-nine patients with pneumothoraces underwent catheter placement in the pleural space for treatment. Of these, 12 pneumothoraces resolved and 17 remained unchanged. We reviewed the charts of these 17 patients to document the cause of malignant pleural effusion, presence of underlying malignant parenchymal disease, volume of fluid aspirated, and improvement in symptoms. Clinical outcome was then evaluated, including size of residual pneumothorax, duration of catheter drainage, and reaccumulation of effusion. RESULTS: No patients' lungs reexpanded despite insertion of large-bore (16- to 35-French) chest tubes. All had pneumothoraces that occupied at least 30% of the hemithorax; all were asymptomatic; all had underlying parenchymal disease and noncompliant lungs. Pleural effusion reaccumulated in all 17 after removal of the chest tube. CONCLUSION: A subgroup of patients with malignant lung parenchymal disease who undergo therapeutic thoracentesis will develop asymptomatic hydropneumothoraces due to poor lung compliance. These patients do not require further catheter drainage. Pleural effusion will reaccumulate in the residual space over a variable period of time.

Radiologic and pathologic correlation of adenomyomatosis of the gallbladder.

BACKGROUND: To demonstrate the radiologic-pathologic correlation of adenomyomatosis of gallbladder (GBA) and emphasize the role of high-resolution real-time ultrasound (RTUS) in the diagnosis of GBA. METHODS: Ten (four male and six female, mean age = 49 years) patients with proven GBA (three diffuse, three segmental, and four fundal) diagnosed by histopathology or confirmed by oral cholecystography (OCG) were reviewed. Radiologic studies included OCG (n = 8), RTUS (n = 8), and computed tomography (CT; n = 4). Six patients subsequently underwent cholecystectomy. RESULTS: Histopathologic correlation between pathologic specimens and OCG, RTUS, and CT was possible in six patients. The diagnostic criteria with ultrasound included numerous tiny intramural cysts containing echogenic foci with reverberation artifacts and associated segmental or diffuse gallbladder wall thickening. OCG with fatty meal demonstrated intramural diverticula. Localized fundal GBA was better visualized on RTUS and CT scan than on OCG. CONCLUSION: Accurate diagnosis of GBA may be made by either OCG or high-resolution RTUS preoperatively. CT scan may used as an alternative method to help make the diagnosis in equivocal cases.

Arterial versus portal venous helical CT for revealing pancreatic adenocarcinoma: conspicuity of tumor and critical vascular anatomy.

OBJECTIVE: The purpose of this study was to determine the conspicuity of pancreatic adenocarcinoma and surrounding critical pancreatic vascular structures on helical CT scans obtained during the arterial and portal venous phases of enhancement. SUBJECTS AND METHODS: Forty patients with pancreatic adenocarcinomas under-went dual-phase helical CT (3-mm collimation; l-mm overlapping reconstructions; 160 ml contrast medium injected at 4 ml/sec; scan delay: 18 sec for arterial phase, 60 sec for portal venous phase). Tissue enhancement and differences in tumor-to-pancreas contrast were compared. Quantitative evaluation was also done for the aorta, the superior mesenteric artery and vein, and the splenic and portal veins. RESULTS: Tumor conspicuity was significantly greater in the portal venous phase, when the tumor-to-pancreas contrast difference was 54 +/- 31 H, than in the arterial phase, when the difference was 31 +/- 29 H. Enhancement values of critical pancreatic venous structures were significantly greater in the portal venous phase than in the arterial phase. CONCLUSION: Arterial-phase helical CT in patients with pancreatic adenocarcinoma is of limited benefit: lesion conspicuity is suboptimal and depiction of venous anatomy is inferior to the depiction possible with venous-phase helical CT.

Anatomic variants of mesenteric veins: depiction with helical CT venography.

OBJECTIVE: The purpose of this study was to describe the variable anatomy of mesenteric veins on axial CT images and on volume-rendered CT venograms that use maximum intensity projection and shaded-surface display. SUBJECTS AND METHODS: Fifty-seven patients undergoing helical CT of the pancreas were included in the study. The mesenteric venous system was analyzed in 54 patients. Three patients were excluded because the helical CT data were unsatisfactory. RESULTS: On helical CT with maximum intensity projection and shaded-surface display, the superior mesenteric vein (SMV) was seen as a single trunk of variable length in 40 patients. In seven other patients, two mesenteric trunks merged separately with the splenic vein. In the remaining seven patients, the SMV was occluded by tumor. The inferior mesenteric vein drained into the splenic vein in 28 patients (56%), into the SMV in 14 patients (26%), and into the splenomesenteric angle in nine patients (18%). CONCLUSION: Both axial and volume-rendered CT venograms accurately reveal the variable mesenteric venous anatomy. CT venograms may replace conventional angiography in presurgical planning.

Mucinous ductal ectasia of the pancreas.

PURPOSE: Pancreatic mucinous ductal ectasia (MDE) is a recently described and poorly understood disorder, with few cases reported in the imaging literature. We undertook this study to describe the spectrum of CT and pancreatographic findings of MDE and to investigate the incidence of associated pancreatic malignancy. METHOD: The medical records, CT scans, and pancreatograms of 12 consecutive patients with pathologically proven MDE were retrospectively reviewed. There were nine men and three women, ranging in age from 37 to 72 years (mean 59 years). RESULTS: Focal lesions involved primarily the uncinate (two patients) and head (eight patients) by CT imaging. The entire gland was involved in two patients. CT findings were variable and included focal pancreatic enlargement, a low attenuation or cystic mass, low attenuation of the entire gland, or marked ductal dilatation. Pancreatographic findings were more consistent, showing ductal dilatation with or without intraluminal filling defects, obstruction, or displacement. In all cases, findings at endoscopy were felt to be characteristic, with ductal dilatation, filling defects, or abundant mucus seen upon cannulation of the pancreatic duct. Carcinoma-in-situ was present in six cases, cellular atypia without malignancy in two, and in three cases the lesions were histologically benign. One case demonstrated invasive adenocarcinoma. No finding or group of findings on CT or pancreatography permitted differentiation between benign and malignant lesions. CONCLUSION: MDE can present with a variety of appearances on CT, none of which is diagnostic. Pancreatography can be diagnostic if dilatation and intraluminal filling defects are seen. Carcinoma-in-situ, invasive adenocarcinoma, or cellular atypia is present in approximately 75%, but cannot be accurately diagnosed prospectively.

Percutaneous gastrostomy with T-fastener gastropexy: results of 316 consecutive procedures.

PURPOSE: To assess the rates of technical success and complications associated with radiologic gastrostomy or gastrojejunostomy performed with T-fastener gastropexy. MATERIALS AND METHODS: In 316 consecutive patients, radiologic gastrostomy or gastrojejunostomy with T-fastener gastropexy was performed over a 10-year period. Results of the procedures were reviewed. Results of follow-up were available for all patients. RESULTS: Of 316 procedures, 314 were successful (technical success rate, 99.4%). Six (1.9%) major complications occurred; 50% occurred in patients with peritoneal involvement from ovarian carcinoma. Ten (3.2%) minor complications occurred. Four minor complications occurred in patients with ovarian cancer and ascites. The 30-day mortality rate was 3.8% (12 patients) with one procedure-related death (0.3%). CONCLUSION: A T-fastener gastropexy may have a protective role in prevention of leakage of gastric contents into the peritoneum in patients with ascites. Ascites need no longer be considered a contraindication for radiologic gastrostomy. A gastropexy enables routine use of larger gastrostomy tubes and ready replacement of a displaced tube even before the development of a mature tract.

Adrenal masses: characterization with delayed contrast-enhanced CT.

PURPOSE: To evaluate the use of attenuation measurements from early delayed computed tomographic (CT) scans to differentiate benign from malignant lesions of the adrenal glands. MATERIALS AND METHODS: Forty-four patients (19 men, 25 women; age range, 21-88 years; mean age, 63 years) with 46 adrenal masses underwent dynamic contrast material-enhanced CT and early delayed CT (range, 12-18 minutes; mean delay, 14 minutes) with similar scanning parameters. Each patient also underwent non-contrast-enhanced CT within 3 months of the contrast-enhanced examination. Attenuation of adrenal masses on each type of scan was measured, and receiver operating characteristic analysis was performed. RESULTS: An attenuation threshold of 24 HU was selected; thus, all lesions with attenuation values of 24 HU or less were considered benign. When this threshold was applied to the results, the sensitivity of characterization of adrenal masses on early delayed scans was 96%, and the specificity was 96%. CONCLUSION: Adrenal masses detected with contrast-enhanced CT can be characterized as benign or malignant on early delayed scans of the adrenal glands.