Role of CT in the diagnosis of jejunal–ileal perforations

Purpose

The purpose of this study was to evaluate the computed tomography (CT) signs of free and covered small-bowel perforations and the potential of CT in recognising the aetiology.

Materials and methods

Thirty-five patients with surgically proven small-bowel perforation were retrospectively evaluated. Fundamental signs (extraluminal air, solution of continuity) and secondary signs (thickening of the mesentery, free or perilesional fluid, wall thickening) were considered.

Results

CT alterations were found in 31/35 (88.6 %) patients: extraluminal air (30/35, 85.7 %), solution of continuity (11/35, 31.4 %), intra-abdominal fluid (27/35, 77.1 %), thickening of the mesentery (20/35, 57.1 %), and wall thickening (14/35, 40 %). In 25/35 cases (71.4 %) pneumoperitoneum was detected, associated with secondary signs (23/25, 82 %), confirmed as free perforations at surgery. In 5/35 patients (14.2 %), peri-intestinal air bubbles and secondary signs were evident, while in 1/35 cases (2.8 %) only secondary signs were seen, namely covered perforations. In 4/35 patients (11.4 %) with a covered perforation, the CT scan was negative. The nature of the perforations was completely recognisable in 26/31 cases (83.9 %), partially identifiable in 4/31 (12.9 %), not evident in 1/31 (3.2 %).

Conclusion

CT investigation is essential in the recognition of a small-bowel perforation and in the definition of its nature.     

CT urography: The end of IVU?

A review of the literature on the diagnostic accuracy of multidetector computed tomography urography (MDCTU) and intravenous urography (IVU) reveals a lack of comparative studies. However, the available data indicate that MDCTU has a high diagnostic accuracy. MDCTU is also preferred by patients, as it does not require bowel preparation. Full acceptance of this technique by the urologist will depend on optimisation of the communication process with a careful selection of the images to be transmitted. MDCTU has a higher cost than IVU but allows some diagnostic algorithms to be simplified. The real concern potentially limiting the widespread use of MDCTU is its higher radiation dose when compared with IVU. Although low-dose protocols will soon be available, a substantial dose reduction can already be achieved by tailoring MDCTU to the clinical problem rather than using a standardised approach. Our analysis indicates that IVU will definitely lose any residual role it may still have. In our department, the last urographic procedure was performed in May 2006.     

Limited value of ⁹⁹mTc depreotide single photon emission CT compared with CT for the evaluation of pulmonary lesions

Objectives

A contrast-enhanced multidetector CT (MDCT) scan is the first choice examination when evaluating patients with suspected lung cancer. However, while the clinical focus is on CT, research focus is on molecular biological methods whereby radiolabelled pharmaceuticals are injected into participants and target malignant lung tumours. We examined whether a contrast-enhanced MDCT scan supplied with an additional non-contrast enhanced high-resolution CT scan, or a newer but more expensive ^99mTc depreotide single photon emission CT (SPECT) scan, was the better first-choice examination for the work-up of pulmonary lesions. Furthermore, we examined whether a ^99mTc depreotide SPECT scan was an appropriate second-choice examination for patients with indeterminate lesions.

Methods

140 participants were included in the analysis. CT images were given a malignancy potential rating of 1, 2 or 3 with higher rating being indicative of disease. ^99mTc depreotide SPECT images were graded either positive or negative. Histopathology and CT follow-up were used as reference standard. Sensitivity, specificity and diagnostic accuracy were calculated.

Results

Overall sensitivity, specificity and diagnostic accuracy of CT were 97%, 30% and 84%, respectively. Overall sensitivity, specificity and diagnostic accuracy of ^99mTc depreotide SPECT were 94%, 58% and 76%, respectively. For indeterminate lesions sensitivity, specificity and diagnostic accuracy of ^99mTc depreotide SPECT were 71%, 68% and 69%, respectively.

Conclusion

Both CT and ^99mTc depreotide SPECT made valuable contributions to the evaluation of pulmonary lesions. ^99mTc depreotide SPECT results were not superior to CT results and did not contribute further to the diagnostic work-up. Regarding indeterminate lesions, ^99mTc depreotide SPECT sensitivity was too low.Lung cancer has a poor prognosis with an overall 5-year mortality rate of approximately 84%. However, with early detection and surgery the mortality rate can be as low as 47% [1]. Lung cancer is a major indication for chest imaging. Many years of CT imaging have seen a steady evolution of methods used to evaluate lung nodules and mass lesions. A contrast-enhanced multidetector CT (MDCT) scan is the first-choice examination when lung cancer is suspected.While the clinical focus is on MDCT, the research focus is on molecular biological methods whereby radiolabelled pharmaceuticals are injected into participants to target malignant lung tumours. Examples of such functional modalities include ^99mTc depreotide single photon emission CT (SPECT) and 18-fluoro-2-deoxyglucose positron emission tomography (18-FDG PET). However, while numerous studies have been published regarding 18-FDG PET, only a limited number, including a preliminary report by our group [2], have focused on ^99mTc depreotide SPECT [3].In this study we examine whether a contrast-enhanced MDCT scan supplied with an additional non-contrast-enhanced high-resolution CT (HRCT) scan or a newer but more expensive ^99mTc depreotide SPECT scan is the better first-choice examination when dealing with the work-up of pulmonary nodules and mass lesions. Furthermore, we examined whether a ^99mTc depreotide SPECT scan is an appropriate second-choice examination for the subgroup of patients with indeterminate lesions.     

Does addition of CT pelvic venography to CT pulmonary angiography protocols contribute to the diagnosis of thromboembolic disease?

AIM: To evaluate the contribution which addition of pelvic computed tomography venography (CTV) to a standard CT pulmonary angiography (CTPA) imaging protocol makes to a definitive diagnosis of thromboembolic disease. MATERIALS AND METHODS: One hundred and six consecutive patients over the age of 55 years referred for (CTPA) for suspected pulmonary embolism between June and November 1999 had pelvic CTV performed at the time of the CTPA study. RESULTS: Ninety-six of 106 CTPA studies were technically adequate. In total, 29/96 (29.6%) CTPA studies were positive for pulmonary embolism, 10/96 (10.4%) CTV studies were positive and five of these 10 examinations showed venous thrombus when the CTPA study was negative (n = 4) or equivocal (n = 1). CONCLUSION: Addition of CTV shows residual thrombus in the pelvis in a proportion of patients with positive CTPA studies and demonstrates venous thrombus in a small number of patients with no CT evidence of pulmonary embolism.     

CT and MRI of Wernicke��s encephalopathy

The purpose of this pictorial essay is to present the computed tomography (CT) and magnetic resonance imaging (MRI) findings of Wernicke's encephalopathy, a rare, severe, acute neurological syndrome due to thiamine (vitamin B1) deficiency, associated with high morbidity and mortality. The classical clinical triad, which includes ocular signs, altered consciousness and ataxia, can be found in only one-third of patients. Although chronic alcoholic patients are the most commonly affected, Wernicke's encephalopathy may complicate malnutrition conditions in nonalcoholic patients, in whom it is greatly underestimated. CT and above all MRI of the brain play a fundamental role in diagnosing the condition and ruling out other diseases. MRI is the most sensitive technique and is required in all patients with a clinical suspicion of Wernicke's encephalopathy. Medial thalami, mamillary bodies, tegmentum, periaqueductal region, and tectal plate are typical sites of abnormal MRI signal. The dorsal medulla, red nuclei, cranial nerve nuclei, cerebellum, corpus callosum, frontal and parietal cerebral cortex are less common sites of involvement although they are more frequently affected in nonalcoholic patients. Paramagnetic contrast material may help to identify lesions not otherwise visible.     

Quantification of liver iron content with CT��added value of dual-energy

Objective  

To evaluate the value of dual-energy CT (DECT) with use of an iron-specific, three-material decomposition algorithm for the quantification of liver iron content (LIC).     

Evaluating the CT diagnosis of Clostridium difficile colitis: should CT guide therapy?

OBJECTIVE: The purpose of this study was to further characterize the CT findings of Clostridium difficile colitis and to provide for the first time a diagnostic sensitivity, specificity, positive predictive value, and negative predictive value to help clinicians decide whether antibiotic treatment is warranted on the basis of CT findings while awaiting stool test results (which may take as long as 48 hr). MATERIALS AND METHODS: A retrospective review covering a 4-year period was performed of the charts and CT scans of 54 symptomatic patients with stool test results positive for C. difficile and of a control group of 56 patients with antibiotic-associated diarrhea with stool test results negative for C. difficile. RESULTS: At our institution, C. difficile colitis was explicitly diagnosed at CT in these patients with a sensitivity of 52%, specificity of 93%, positive predictive value of 88%, and negative predictive value of 67%. The sensitivity can be raised to 70% with no change in specificity with more rigid adherence to diagnostic criteria of colon wall thickening of greater than 4 mm combined with any one or more findings of pericolonic stranding, colon wall nodularity, the "accordion" sign, or otherwise unexplained ascites. CONCLUSION: Although routine CT screening of antibiotic-associated diarrhea is not advocated, the 88% positive predictive value of a diagnosis of C. difficile colitis in those who are scanned may merit consideration of treatment by clinicians on the basis of the CT results alone.     

Usefulness of PET–CT in the assessment of suspected recurrent colorectal carcinoma

Purpose

To evaluate the usefulness of PET/CT in detecting recurrent colorectal carcinoma (CRCR) in patients subsequent to colonic resection or rectal amputation and to compare it with the PET part of integrated FDG-PET/CT.

Materials and methods

PET/CTs from 32 patients with suspected CRCR were studied. Histology, clinical follow-up and additional imaging served as the gold standard. The sensitivity, specificity, positive and negative predictive values (PPV, NPV), and accuracy of PET as well as integrated PET/CT were calculated and compared for each of (a) intra-abdominal extra-hepatic recurrences, (b) extra-abdominal and/or hepatic recurrences, and (c) any form of CRCR.

Results

PPV, sensitivity, NPV, specificity and accuracy of PET in detecting intra-abdominal extra-hepatic CRCR were, respectively, 85.7%, 85.7%, 88.9%, 88.9%, and 87.5% compared with 92.9%, 92.9%, 94.5%, 94.5%, and 93.8%, respectively, for PET/CT. The corresponding values for the detection of extra-abdominal and/or hepatic CRCR were 84.6%, 84.6%, 89.5%, 89.5%, and 87.5% for PET versus 100%, 92.3%, 95%, 100%, and 96.9% for PET/CT. For all forms of recurrence, the corresponding values for PET were 80%, 80%, 66.7%, 66.7%, and 75%, respectively, compared with 94.5%, 90%, 84.6%, 91.7%, and 90.6%, respectively, for PET/CT.

Conclusion

PET/CT enhances the accuracy and specificity of diagnosis of CRCRa. PET/CT grows to reach prominent roles for imaging and restaging of patients after colorectal carcinoma resection.     

Comparison of sonographic and CT guidance techniques: does CT fluoroscopy decrease procedure time?

OBJECTIVE: Procedure times for percutaneous biopsies were compared for various guidance techniques including helical CT, CT fluoroscopy, sonography with an attached needle guide, and freehand sonography with computer guidance. MATERIALS AND METHODS: Three interventional radiologists experienced in CT- and sonographically guided procedures performed biopsies on a phantom model. The phantom simulated hepatic metastases of various sizes and depths with subcostal or intercostal locations. Lesion sizes were 7, 10, and 20 mm, at 3- and 7-cm depths. Using self-aspirating needles, two passes were performed in each lesion. Mean procedure time per biopsy pass was calculated. A two-tailed Student's t test was used to compare guidance techniques. RESULTS: Mean procedure time per biopsy pass for the four guidance techniques was sonography with a needle guide, 36+/-9 sec; sonography with computer guidance, 43+/-10 sec; helical CT, 146+/-42 sec; and CT fluoroscopy, 50+/-18 sec. CT fluoroscopy required 2.6+/-1.0 sec per biopsy. Helical CT required more procedure time than sonography with a needle guide, CT with computer guidance, and CT fluoroscopy (p < 0.0001). Sonography with a needle guide required less procedure time than sonography with computer guidance (p < 0.002) and CT fluoroscopy (p = 0.0003). Procedure times for CT fluoroscopy and sonography with computer guidance were not statistically different (p = 0.06). CT and sonographic guidance were equally effective regardless of lesion size, depth, or location. CONCLUSION: Traditional sonographic biopsy techniques are faster and more cost-effective than traditional CT techniques; however, CT fluoroscopy offers the localization advantages of CT with improved procedure times.     

A comparative study of evaluation of radiographs, CT and 3D reformatted CT in facial trauma: what is the role of 3D?

A panel of 17 trainee maxillofacial surgeons viewed 23 cases of facial trauma, demonstrated on radiographs, axial CT images and three-dimensional (3D) reformatted CT images in a standardized viewing format under standard conditions. Their diagnostic interpretation, extraction of information relevant to surgical management and subjective evaluation of each modality were recorded by standard questionnaire and compared with a gold standard evaluation by a consultant radiologist and surgeon reading based on results of clinical management. There were clear and measurable differences in the viewers' evaluations of radiographs, CT and 3D reformatted images. Overall, surgeons showed more accurate diagnostic reading of radiographs and 3D reformatted images. This was in contrast to their subjective assessment of the clinical value of each modality, which showed a strong preference for 3D over all other techniques and for CT over radiographs. However the perceived benefit of axial CT images over radiographs was not reproduced on objective testing in this group; surgeons appear to perform less well in interpreting CT images than their subjective response to the modality would suggest. This work has supported the view that surgeons value 3D imaging as a front-line tool in the evaluation and management of selected cases of acute facial trauma. We have demonstrated that the perceived benefits of 3D reformatted CT to surgeons appear real.     

The Correlative Analysis of CT Findings and Pathology of Type Ⅰ Infant Liver Hemangioendothelioma

目的 对照分析Ⅰ型婴儿型肝脏血管内皮细胞瘤的CT表现与病理,旨在提高其影像诊断水平.资料与方法 经手术病理证实的Ⅰ型婴儿型肝脏血管内皮细胞瘤9例;男4例,女5例,年龄3天～5个月,中位年龄1.56个月.全部病例术前经CT检查,对照术后病理结果总结分析肿瘤的大小、形态、密度以及CT增强表现.结果 CT平扫表现为肝内低密度灶,8例单发病变位于肝左叶5例、肝右叶3例且其中7例肝脏局部膨隆,弥漫分布1例,边缘无膨隆;6例单发病灶内有颗粒样、斑点状、条索样钙化灶,无钙化有3例分别为单发2例、多发1例;增强动脉晚期及门静脉期病变由周边向中心呈结节样、环形、花瓣样强化,延迟后密度与周围正常相等或稍高,其中4例肿瘤坏死中心始终不强化;血管重组显示7例单发病灶内见呈迂曲条索样、线条样丰富血管影.结论 Ⅰ型婴儿型肝脏血管内皮细胞瘤CT表现具有一定特征,与病理有较高的一致性,认识其CT表现及病理基础,有助于诊断及鉴别诊断.     

The use of FDG-PET/CT in extranodal Rosai–Dorfman disease of bone

We report the case of a 41-year-old man with extranodal Rosai-Dorfman disease (RDD), presenting with clinically detectable bone involvement only. The use of FDG-PET/CT in the diagnosis of RDD is discussed.     

Dose and image quality at CT pulmonary angiography��comparison of first and second generation dual-energy CT and 64-slice CT

Objective  

To compare dose and image quality of 64-slice, first and second generation dual-energy CT (DECT) for CT pulmonary angiography (CTPA).     

Performance of integrated FDG–PET/contrast-enhanced CT in the diagnosis of recurrent ovarian cancer: comparison with integrated FDG–PET/non-contrast-enhanced CT and enhanced CT

PURPOSE: The aim of this study was to evaluate the accuracy of integrated positron emission tomography and computed tomography (PET/CT) using (18)F-fluorodeoxyglucose with IV contrast for depiction of suspected recurrent ovarian cancer and to assess the impact of PET/contrast-enhanced CT findings on clinical management, compared with PET/non-contrast-enhanced CT and CT component. METHODS: One hundred thirty-two women previously treated for ovarian cancer underwent PET/CT consisting of non-enhanced and contrast-enhanced CT for suspected recurrence. PET/contrast enhanced CT, PET/non-contrast-enhanced CT, and enhanced CT were interpreted by two experienced radiologists by consensus for each investigation. Lesion status was determined on the basis of histopathology, radiological imaging, and clinical follow-up for longer than 6 months. RESULTS: Patient-based analysis showed that the sensitivity, specificity, and accuracy of PET/contrast-enhanced CT were 78.8% (52 of 66), 90.9% (60 of 66), and 84.8% (112 of 132), respectively, whereas those of PET/non-contrast-enhanced CT were 74.2% (49 of 66), 90.9% (60 of 66), and 82.6% (109 of 132), respectively, and those of enhanced CT were 60.6% (40 of 66), 84.8% (56 of 66), and 72.7% (96 of 132), respectively. Sensitivity, specificity, and accuracy differed significantly among the three modalities (Cochran Q test: p = 0.0001, p = 0.018, and p < 0.0001, respectively). The findings of PET/contrast-enhanced CT resulted in a change of management for 51 of the 132 patients (39%) and had an effect on patient management in 16 patients (12%) diagnosed by enhanced CT alone and three patients (2%) diagnosed by PET/non-contrast-enhanced CT. CONCLUSION: Integrated PET/contrast-enhanced CT is an accurate modality for assessing ovarian cancer recurrence and led to changes in the subsequent appropriate therapy.     

Fitz-Hugh–Curtis syndrome: CT findings of three cases

Clinical manifestations and computed tomography (CT) findings of Fitz-Hugh–Curtis syndrome (FHCS) are relatively well stabilized as right upper quadrant abdominal pain and hepatic capsular enhancement because of perihepatitis associated with pelvic inflammatory disease caused by N. gonorrhoeae and C. trachomatis. We encountered three patients with serial FHCS associated with pelvic inflammatory disease, who visited the emergency room with right upper quadrant abdominal pain. Abdominal CT revealed hepatic capsular or pericapsular enhancement along the anterior surface of the liver on the arterial phase. Recently, multi-detector CT has evolved as the first-line imaging modality of acute abdomen at the emergency room; we reemphasized the importance of the CT findings of this syndrome for differential diagnosis of right upper quadrant abdominal pain in sexually active young women. Physicians at the emergency room acknowledge the syndrome and should perform dynamic abdominopelvic CT including the arterial phase.