Contrast-enhanced Helical Computed Tomography Research Articles

Evaluating aortomesenteric parameters in a tertiary center of Nepal for superior mesenteric artery syndrome diagnosis and risk factors: cross-sectional study.

This study examines aortomesenteric angle (AMA) and distance (AMD), which are critical in superior mesenteric artery (SMA) syndrome. Addressing the scarcity of SMA cases, the research explores potential links with lower BMI and aims to establish normative data for diagnostic and predictive purposes, using contrast-enhanced computed tomography (CT) scans across various BMI and sex categories. A retrospective quantitative cross-sectional study was conducted on 189 patients undergoing abdominal contrast-enhanced CT scans between December 2019 and December 2020. Ethical clearance was obtained, and participants provided informed consent. Exclusion criteria targeted specific medical histories. Patient demographics, BMI categories, and imaging data were recorded. Helical 128-slice CT scans were employed, with sagittal-oblique multiplanar reconstructions for parameter assessments. Statistical analysis utilized SPSS 26.0, including Pearson correlation coefficients and mean calculations. The study reveals a mean AMA of 54.07°±8.53° and a mean distance of 16.25±3.44 mm. Elevated BMI is found to positively correlate with AMA and distance, indicating that higher BMI values may augment these parameters, with an additional positive correlation observed between AMA and distance. No significant correlations are found with patient age or sex. The study concludes that decreased BMI may pose a potential risk for SMA syndrome, as evidenced by the observed correlations with aortomesenteric parameters. Understanding these normal values in the Nepalese population is critical for accurate diagnoses and predictions using CT scans. The research highlights the impact of demographic factors on these parameters and emphasizes their significance in clinical assessments related to SMA syndrome.

An Evaluation Analysis for Computed Tomography Image Quality of Primary Liver Cancer Lesions Based on Deep Learning Image Reconstruction.

Abdominal multi-slice helical computed tomography (CT) and contrast-enhanced scanning have been widely recognized clinically. The impact of the deep learning image reconstruction (DLIR) on the quality of dynamic contrast-enhanced CT imaging of primary liver cancer lesions was evaluated through comparison with the filtered back projection (FBP) and the new generation of adaptive statistical iterative reconstruction-V (ASIR-V). We evaluated the image noise of the lesion, fine structures inside the lesion, and diagnostic confidence in 48 liver cancer subjects. The CT values of the solid part of the lesion and the adjacent normal liver tissue and the systolic and diastolic blood pressure (SD) values of the right paravertebral muscle were measured. The muscle SD value was considered as the background noise of the image, and the signal noise ratio (SNR) and contrast signal-to-noise ratio (CNR) of the lesion and normal liver parenchyma were calculated. High consistency in the evaluation of image noise (Kappa = 0.717). The Kappa values for margin/pseudocapsule, fine structure within the lesion, and diagnostic confidence were 0.463, 0.527, and 0.625, respectively. Besides, the differences in SD, SNR and CNR data of reconstructed lesion images among the six groups were statistically significant. The contrast-enhanced CT image noise of DLIR-H in the portal venous phase is much lower than that of ASIR-V and FBP in primary liver cancer patients. In terms of the lesion structure display, the new reconstruction algorithm DLIR is superior.

A Giant Ileal Conduit Calculus after Radical Cystectomy

Radical cystectomy with ileal conduit is one of the treatment options for patients with muscle invasive carcinoma bladder. Giant ileal conduit calculus is a very rare complication. A 60-year-old male had undergone radical cystectomy with ileal conduit about 12 years back and now presented left gross hydrourereteronephrosis with perinephric collection and features of renal failure. We performed drainage of perinephric collection followed by left sided percutaneous nephrostomy and patient's condition improved gradually. Later on, we performed contrast-enhanced computed tomography (CT) intravenous urogram and nephrostogram which revealed a huge calculus of size 9 cm × 5 cm in the ileal conduit. Calculus was removed by open surgery by incising the conduit over antimesenteric border. Above presentation is a sequel of a huge ileal conduit calculus obstructing left ureter. Calculus formation can result from stomal stenosis, metabolic acidosis, small bowel syndrome, recurrent infection, any foreign body like a staple or nonabsorbing suture material. These patients require close surveillance with X-ray kidney, ureter, and bladder for a longer period after the urinary diversion. In doubtful cases, helical CT may be useful. Giant ileal conduit calculus is a very uncommon presentation after radical cystectomy.

Endoscopic ultrasonography for pancreatic cancer: current and future perspectives.

A suspected pancreatic lesion can be a difficult challenge for the clinician. In the last years we have witnessed tumultuous technological improvements of the radiological and nuclear medicine imaging. Taking this into account, we will try to delineate the new role of endoscopic ultrasound (EUS) in pancreatic imaging and to place it in a shareable diagnostic and staging algorithm of pancreatic cancer (PC). To date the most accurate imaging techniques for the PC remain contrast-enhanced computed tomography (CT) and EUS. The latter has the highest accuracy in detecting small lesions, in assessing tumor size and lymph nodes involvement, but helical CT or an up-to-date magnetic resonance imaging (MRI) must be the first choice in patients with a suspected pancreatic lesion. After this first step there is place for EUS as a second diagnostic level in several cases: negative results on CT/MRI scans and persistent strong clinical suspicion of PC, doubtful results on CT/MRI scans or need for cyto-histological confirmation. In the near future there will be great opportunities for the development of diagnostic and therapeutic EUS and pancreatic pathology could be the best testing bench.

Percutaneous interventional procedures in an era of liver transplantation

Percutaneous interventional procedures in an era of liver transplantation

Fractal Dimension Analysis of MDCT Images for Quantifying the Morphological Changes of the Pulmonary Artery Tree in Patients with Pulmonary Hypertension

ObjectiveThe aim of this study was to use fractal dimension (FD) analysis on multidetector CT (MDCT) images for quantifying the morphological changes of the pulmonary artery tree in patients with pulmonary hypertension (PH).Materials and MethodsFourteen patients with PH and 17 patients without PH as controls were studied. All of the patients underwent contrast-enhanced helical CT and transthoracic echocardiography. The pulmonary artery trees were generated using post-processing software, and the FD and projected image area of the pulmonary artery trees were determined with ImageJ software in a personal computer. The FD, the projected image area and the pulmonary artery pressure (PAP) were statistically evaluated in the two groups.ResultsThe FD, the projected image area and the PAP of the patients with PH were higher than those values of the patients without PH (p < 0.05, t-test). There was a high correlation of FD with the PAP (r = 0.82, p < 0.05, partial correlation analysis). There was a moderate correlation of FD with the projected image area (r = 0.49, p < 0.05, partial correlation analysis). There was a correlation of the PAP with the projected image area (r = 0.65, p < 0.05, Pearson correlation analysis).ConclusionThe FD of the pulmonary arteries in the PH patients was significantly higher than that of the controls. There is a high correlation of FD with the PAP.

Secretin-assisted CT of the pancreas: improved pancreatic enhancement and tumour conspicuity

The primary aim of this prospective pilot study was to determine if the administration of intravenous secretin prior to contrast-enhanced computed tomography (CT) improves pancreatic enhancement and pancreatic tumor conspicuity. The second aim was to determine the optimal timing for secretin administration prior to contrast-enhanced CT. Local ethics committee approval was obtained. 35 patients (18 men, 17 women; mean age, 67.6 years; age range; 25 to 86 years) with known or suspected pancreatic malignancy or an abdominal malignancy underwent a helical CT of the pancreas. The pancreas was first localised on an unenhanced scan using 10mm sections. Following 120 ml of intravenous 300 mg/ml of non ionic contrast medium (CM), injected at a rate of 5 ml/s, images of the pancreas (3mm slice thickness) and liver (8mm slice thickness) were obtained at 40 and 70 seconds respectively. A second CT was obtained 1-5 days after the first one using the same CT and intravenous contrast medium injection parameters. However 100 IU of secretin was given as an intravenous bolus between 0 and 5 min prior to intravenous contrast medium administration. Each patient acted as their own control. The attenuation in Hounsfield Units (HU) was recorded on non-contrast, pancreatic phase and portal venous phases for both secretin and non-secretin CTs, in the pancreas and pancreatic tumors (where present). Tumor conspicuity was calculated (in the 19 patients with pancreatic adenocarcinomas) by subtracting pancreatic tumor attenuation from pancreatic attenuation. Statistical evaluation comparing pre and post secretin enhancement was performed using matched paired t-tests. A significant increase in pancreatic enhancement was observed when secretin was injected at 2 to 3 min before contrast material injection (the increase in pancreatic density following secretin at 2 min was 31.5+/-10 HU (29.2%) (p=.035); and at 3 min was 23.2+/-7.8 HU (22.7%) (p=.041). Pancreatic tumor conspicuity in the pancreatic phase was most marked when secretin was injected between 2 to 4 min before contrast medium, with 4 min showing a statistically significant increase in tumor conspicuity, 48.2+/-14.2 HU (p=.04). Imaging in the pancreatic phase 2 to 4 min after administration of intravenous secretin leads to greater enhancement of the pancreas with greater tumor conspicuity, than imaging without secretin.

Management of liver hemangiomas according to size and symptoms

Liver hemangiomas are the most common benign liver tumors. These lesions are usually incidental findings during imaging studies of the abdomen performed for other reasons. The indication for surgical resection of these lesions remains controversial. Records of patients referred for evaluation of radiologically and/or histopathologically proven liver hemangiomas, from June 1991 to February 2006, were retrospectively analyzed. Reason for referral, results of imaging studies, and surgical treatment and outcome were reviewed. There were 34 patients identified. The hemangioma size was <5 cm in 15 patients (44%) and >5 cm in 19 patients. The most common reason for referral was right upper abdominal pain in 59% (20/34) of patients. Abdominal ultrasound was conclusive in 66.7% (16/24) and four-phase computed tomography (CT) in 82.6% (19/23) of patients. Surgical resection was undertaken in 14 patients (41%) after a mean follow-up time of 36.5 months. The indication for treatment was progressive abdominal pain in 78.6% (11/14). Mean size of resected lesions was larger compared to non-resected lesions (10.3 vs 4.8 cm; P = 0.004). Postoperative morbidity occurred in three patients (21.4%). One patient had persisting abdominal pain after resection of an 8-cm hemangioma. Twenty patients were observed and showed no complications related to the liver hemangioma during follow-up. Liver hemangiomas can be readily diagnosed by ultrasound or multiphase contrast-enhanced helical CT. The indications for surgical resection are progressive abdominal pain in combination with size >5 cm. Observation is justified in patients with minimal or no symptoms, even in patients with giant hemangiomas.

Diagnosis of small hepatic nodules detected by surveillance ultrasound in patients with cirrhosis: Comparison between contrast‐enhanced ultrasound and contrast‐enhanced helical computed tomography

To investigate the diagnostic value for the diagnosis of small (1-2 cm) hepatic nodules detected by surveillance ultrasound in patients with cirrhosis using contrast-enhanced ultrasound (CEUS) compared with that of contrast-enhanced helical computed tomography (CECT). Seventy-two liver cirrhosis patients with 103 small hepatic nodules (1-2 cm) detected by surveillance ultrasound were enrolled in the present study. All patients underwent CEUS with SonoVue as well as CECT. Nodules which appeared by contrast enhancement during the arterial phase and contrast wash-out during the late phase on CEUS or CECT were diagnosed as malignant (hepatocellular carcinoma [HCC]). Histopathology obtained from biopsy or surgery served as the gold standard. According to the above diagnostic criteria, the sensitivity (i.e. rate of correct diagnosis of HCC) was 91.1% (51/56 HCC) for CEUS and the specificity (i.e. the rate of correct exclusion of HCC) was 87.2% (41/47 regenerative nodules [RN]).Therefore, the diagnostic accuracy of CEUS was 89.3% (92/103 all nodules). Using the same diagnostic criteria, the sensitivity, specificity and accuracy of CECT were 80.4% (45/56 HCC), 97.9% (46/47 RN), and 88.4% (91/103 all nodules). Overall, there was no significant difference between CEUS and CECT in the diagnostic confidence of small hepatic nodules. Eighty-six nodules (45 HCC and 41 RN) were correctly diagnosed by both modalities and six (five HCC and one RN) were misdiagnosed by both. The ability of CEUS in the characterization of small nodules (1-2 cm) detected by surveillance US in patients with liver cirrhosis is similar to that of CECT.

Value of contrast-enhanced ultrasonography for detecting renal infarcts proven by contrast enhanced CT. A feasibility study

The effectiveness of contrast-enhanced ultrasonography (CEUS) in the evaluation of patients with acute renal infarcts was investigated, using contrast-enhanced helical computed tomography (CT) as the reference imaging procedure. Twenty-seven consecutive patients with acute renal infarcts detected with contrast-enhanced helical CT underwent CEUS. Digital cine-clips of CEUS were evaluated by two independent readers blinded to CT findings. Image quality was rated subjectively on a four-point scale. Then, readers were asked to assign a confidence level in diagnosis of renal infarct at the upper pole, medium portion, and lower pole of each kidney according to a five-degree scale, ranging from definitely absent to definitely present. ROC curve analysis was employed to assess the overall confidence of diagnosis of infarct, and weighted kappa values were calculated to assess inter-reader agreement. The subjective image quality of CEUS was lower than the image quality of CT at the upper poles. However, the diagnostic performance of CEUS was excellent (area under receiver-operator characteristic curve 0.992 +/- 0.006 for reader 1; 0.991 +/- 0.007 for reader 2), with very good inter-reader agreement (weighted kappa value = 0.83). CEUS is a reproducible tool to detect acute renal infarcts in men, with a diagnostic performance approaching that of CT.

Evaluation of renal arteries in living renal donors: comparison between MDCT angiography and gadolinium-enhanced 3D MR angiography

The purpose of this study was to clarify and compare the accuracy of contrast-enhanced computed tomography (CT) angiography using multidetector-row helical CT (MDCT angiography) and gadolinium-enhanced MR angiography using three-dimensional Fourier transformation gradient-echo sequence (3D MR angiography) for preoperative evaluation of renal arteries in living renal donors. A total of 42 living renal donor candidates underwent both MDCT angiography and 3D MR angiography before digital subtraction angiography (DSA). Each MDCT angiogram and 3D MR angiogram was prospectively interpreted, and the findings were compared with the DSA results. MDCT angiography identified all of the 12 supernumerary arteries detected by DSA, whereas 3D MR angiography identified only 8. MDCT angiography identified all of the 19 proximal arterial branches detected by DSA, whereas 3D MR angiography identified only 16. A more accurate depiction of renal arteries in living renal donors can be achieved with MDCT angiography than with 3D MR angiography.

Radiofrequency ablation therapy combined with suture and ligation surgery for patients with giant cavernous hemangiomas of the liver

To evaluate the feasibility and efficacy of radiofrequency ablation (RFA) therapy combined with suture and ligation surgery for patients with giant hepatic cavernous hemangioma (HCH). Between June 2004 and June 2005, a total of 30 patients were treated by RFA therapy after suture and ligation surgery (SL group, n = 15, with 18 liver lesions) or RFA therapy without suture and ligation surgery (non-SL group, n = 15, with 17 liver lesions) under general anesthesia. All patients had obvious symptoms such as abdominal discomfort, pain and swelling. Preoperative diagnosis of HCH was established by means of ultrasonography, helical computed tomography (CT) scans, and magnetic resonance imaging (MRI). The mean maximum diameter of the lesions was 8.8 cm +/- 1.4 cm. All of the 35 lesions were located on the liver surface, in the caudate lobe of the liver, or adjacent to the gallbladder. Seven patients had chronic calculous cholecystitis, 6 common duct stones, 5 thrombocytopenias, and one posthepatitic cirrhosis. Thirteen of the 30 patients had previous laparotomy. Therapeutic efficacy and clinical data of RFA therapy were compared between these two groups. RFA therapy under ultrasound guidance was performed successfully in all the patients. Cholecystectomy was performed simultaneously for gallstones in 7 patients and for abutting of gallbladder from hemangioma in 2 patients. Choledochotomy with T-tube drainage was performed in 6 patients. The mean blood loss, the mean RFA time per lesion and reduction rate of maximum diameter of the lesions 6 months after RFA in the SL group and non-SL group were 88.0 ml +/- 22.4 ml vs. 255.0 ml +/- 71.7 ml (P < 0.001), 23.0 min +/- 7.5 min vs. 53.3 min +/- 16.0 min (P < 0.001), and 61.8% vs. 44.8% (P < 0.001) respectively. No severe complication related to RFA was observed in all patients. At a median follow-up of 12 months (6 approximately 17 months), a complete lesion necrosis was achieved on the contrast-enhanced helical CT scans in both groups. During the follow-up, all of the 15 patients were free of upper abdominal pain in the SL group, and 12 patients were symptom-free and 3 obtained significant amelioration of symptoms in the non-SL group. RFA therapy combined with suture and ligation surgery is a feasible, safe, and effective treatment modality for patients with giant HCHs. It can reduce blood loss, shorten RFA therapy time, and increase therapeutic efficacy of RFA. Intraoperative ultrasonography is a useful adjunct for increasing the therapeutic efficacy of RFA and reducing the complications related to RFA.

Diagnosis of intrahepatic and common duct stones: Combined unenhanced and contrast-enhanced helical CT in 1090 patients

We determined the accuracy of combined unenhanced and contrast-enhanced helical computed tomography (CT) for diagnosis of bile duct stones. During a 12-month period, 1090 patients who underwent combined CT and endoscopic retrograde cholangiography (ERC) or percutaneous transhepatic cholangioscopy (PTC) were enrolled in this study. The results of prospective CT interpretation regarding the presence of bile duct stones were compared with results of endoscopic stone removal, PTC and with surgical results. In 70 patients, detectability of stones on CT was evaluated depending on stone types. Of 1090 study patients, 175 and 299 patients were confirmed to have intrahepatic and common duct stones, respectively. The sensitivity and specificity of combined CT were 73% and 98% for diagnosis of intrahepatic stones and 71% and 97% for common duct stones. Of 70 patients 24, 25, and 21 patients had cholesterol, black pigment, and brown pigment stones, respectively. Eleven of 24 cholesterol stones, 21 of 25 black pigment stones, and 15 of 21 brown pigment stones were detected on combined CT. Combined CT is of limited sensitivity for detection of bile duct stones, especially in Western countries where cholesterol stones predominate. It may be of greater value in populations with a higher incidence of pigment stones. Other complementary imaging modalities are needed for patients with negative CT findings who are highly suspected to have biliary stones.

Triphasic helical CT in Budd–Chiari syndrome: patterns of enhancement in acute, subacute and chronic disease

To retrospectively evaluate helical computed tomography (CT) findings in a series of consecutive patients with Budd-Chiari syndrome. Patterns of enhancement observed at contrast-enhanced helical CT in 10 consecutive patients (six women, four men; aged 27-51 years) with either acute, subacute or chronic Budd-Chiari syndrome were retrospectively evaluated along with the status of the hepatic veins. All patients underwent triphasic helical CT (10 mm beam collimation, 7 mm rec. intervals, 120 kV, 200-250 mA, pitch = 1.0) performed at 20-25, 70-75 and 300 s after i.v. bolus (3 ml/s) injection of 150 ml iodinated non-ionic contrast media. Abnormal patterns of enhancement were identified in eight patients. In all patients with acute Budd-Chiari disease (3/3) abnormal arterial enhancement of the caudate lobe, the so-called "fan-shaped pattern" was observed, whereas visible venous thrombosis was only depicted in two. Conversely, a "patchy pattern" of enhancement was observed in five out of seven patients with either sub-acute (2) or chronic Budd-Chiari disease (5) along with a strip-like appearance or lack of visualization of hepatic veins. The "fan-shaped" pattern of enhancement represent a characteristic finding of acute Budd-Chiari disease, and it may help to suggest the correct diagnosis even in absence of visible venous thrombosis.

Volumetric Analysis of Liver Metastases in Computed Tomography With the Fuzzy C-Means Algorithm

Tumor size is often determined from computed tomography (CT) images to assess disease progression. A study was conducted to demonstrate the advantages of the fuzzy C-means (FCM) algorithm for volumetric analysis of colorectal liver metastases in comparison with manual contouring. Intra-and interobserver variability was assessed for manual contouring and the FCM algorithm in a study involving contrast-enhanced helical CT images of 43 hypoattenuating liver lesions from 15 patients with a history of colorectal cancer. Measurement accuracy and interscan variability of the FCM and manual methods were assessed in a phantom study using paraffin pseudotumors. In the clinical imaging study, intra-and interobserver variability was reduced using the FCM algorithm as compared with manual contouring (P = 0.0070 and P = 0.0019, respectively). Accuracy of the measurement of the pseudotumor volume was improved using the FCM method as compared with the manual method (P = 0.047). Interscan variability of the pseudotumor volumes was measured using the FCM method as compared with the manual method (P = 0.04). The FCM algorithm volume was highly correlated with the manual contouring volume (r = 0.9997). Finally, the shorter time spent in calculating tumor volume using the FCM method versus the manual contouring method was marginally statistically significant (P = 0.080). These results suggest that the FCM algorithm has substantial advantages over manual contouring for volumetric measurement of colorectal liver metastases from CT.

Dynamic helical CT mammography of breast cancer

The purpose of this study was to determine whether dynamic helical computed tomography (CT)-mammography could assist in selecting the most appropriate surgical method in women with breast cancer. Preoperative contrast-enhanced helical CT scanning of the breast was performed on 133 female patients with suspicion of breast cancer at the same time as clinical, mammographic, and/or ultrasonographic examinations. The patients were scanned in the prone position with a specially designed CT-compatible device. A helical scan was made with rapid intravenous bolus injection (3 ml/s) of 100 ml of iodine contrast material. Three-dimensional maximum intensity projection (MIP) images were reconstructed, and CT findings were correlated with surgical and histopathological findings. Histopathological analysis revealed 84 malignant lesions and seven benign lesions. The sensitivity, specificity, and accuracy levels of the CT scanning were 94.6%, 58.6%, and 78.9%. Helical scanning alone revealed additional contralateral carcinomas in three of four patients and additional ipsilateral carcinomas in three of five patients. However, the technique gave false-positive readings in 24 patients. The preoperative CT-mammogram altered the surgical method in six patients. Dynamic helical CT-mammography in the prone position may be one of the choices of adjunct imaging in patients with suspected breast cancer scheduled for surgery.

Accuracy of Helical Computed Tomography and [18F] Fluorodeoxyglucose Positron Emission Tomography for Identifying Lymph Node Mediastinal Metastases in Potentially Resectable Non–Small-Cell Lung Cancer

Computed tomography (CT) and [18F] Fluorodeoxyglucose positron emission tomography (FDG-PET) are considered suitable methods for the noninvasive staging of the mediastinum. Our study was intended to estimate the efficacy of contrast-enhanced helical CT (hCT) and FDG-PET, alone and combined, in the diagnosis of lymph node mediastinal metastases. This study was a prospective and blind comparison of the efficacy of hCT and FDG-PET with two alternative reference standards, mediastinoscopy, and mediastinoscopy plus thoracotomy plus a 6-month follow-up to diagnose lymph node mediastinal metastases in 132 consecutive patients with potentially resectable non-small-cell lung cancer (NSCLC). The metastatic disease was assessed histopathologically. Further clinical information was obtained postoperatively after a median follow-up of 42 months. The prevalence of cN2,3 is 0.28. For hCT the sensitivity and specificity are 0.86 (95% CI, 0.70 to 0.93) and 0.67 (95% CI, 0.56 to 0.75), for PET 0.94 (95% CI, 0.81 to 0.98) and 0.59 (95% CI, 0.49 to 0.68), and for hCT and PET combined in-parallel 0.97 (95% CI, 0.84 to 0.99) and 0.44 (95% CI, 0.34 to 0.53), which translate into a negative predicted probability of 0.98 (95% CI, 0.88 to 1.00). The crude diagnostic odds ratio of PET in the total sample studied is 13.1, in the subgroup hCT+ 11.04 (3.0 to 40 0.1), and in the hCT- 3.5 (0.5 to 21.5). Similar results were obtained for hCT stratified by PET. hCT and PET perform similarly in the mediastinal staging of NSCLC, both tests are conditionally dependent and provide complementary information, and their diagnostic value mainly resides on the negative results.

Bone Invasion in Patients with Oral Cavity Cancer: Comparison of Conventional CT with PET/CT and SPECT/CT

To prospectively compare the accuracy of helical contrast material-enhanced computed tomography (CT) with that of CT and positron emission tomography (PET) combined and CT and single photon emission CT (SPECT) combined in the detection of bone invasion in patients scheduled to undergo surgery for clinically suspected oral cavity carcinoma with possible bone invasion, with surgical results as the reference standard. This study had local ethical committee approval, and all patients gave written informed consent. Thirty-four consecutive patients (17 men, 17 women; mean age, 64.2 years; age range, 46.0-84.6 years) who were clinically suspected of having bone invasion from oral cavity carcinoma prospectively underwent helical contrast-enhanced CT, coregistered PET/CT, and coregistered SPECT/CT. Two radiologists assessed the contrast-enhanced CT images and two nuclear medicine physicians separately assessed the PET/CT and SPECT/CT images in consensus and without knowledge of the results of other imaging tests. The presence of bone involvement as suggested with an imaging modality was compared with histologic findings in the surgical specimen. With histologic findings as the standard of reference, the accuracy of SPECT/CT (88% [30 of 34 patients]) was lower than that of PET/CT and contrast-enhanced CT (94% [32 of 34 patients] and 97% [33 of 34 patients], respectively). Sensitivity was highest with PET/CT (100% [12 of 12 patients]), and specificity was highest with contrast-enhanced CT (100% [22 of 22 patients]). Fluorine 18 fluorodeoxyglucose (FDG) uptake seen on two sides of the same cortical bone was not a helpful imaging pattern for better identifying bone invasion in patients without evident cortical erosion on CT scans. The assessment of cortical erosion with contrast-enhanced CT and the CT information from PET/CT are the most reliable methods for detecting bone invasion in patients with oral cavity carcinoma. FDG uptake seen on PET/CT images does not improve identification of bone infiltration.

Fungal Liver Infection in Immunocompromised Patients: Depiction with Multiphasic Contrast-enhanced Helical CT

To retrospectively assess multiphasic (nonenhanced, arterial phase, and portal venous phase) computed tomography (CT) of the liver for depiction of hepatic fungal infection in immunocompromised patients. The institutional ethics review board approved the study and waived the requirement for informed consent. Sixty multiphasic hepatic CT examinations were performed in 39 immunocompromised patients who fulfilled the criteria for having probable or proved fungal liver infection. The detection and conspicuity of focal liver lesions were assessed on scans obtained during each CT phase. The lesion enhancement pattern was determined, and, accordingly, lesions were stratified into two groups: lesions suggestive of infection (with ring enhancement patterns or high attenuation) and nonspecific hypoattenuating lesions. Statistical analyses were performed by using logistic regression with generalized estimating equations. A total of 536 liver lesions detected at 36 CT examinations with results positive for fungal infection were assessed. All 36 (100%) examinations yielded positive results during the arterial phase, whereas 25 (69%) of them yielded positive results during the portal venous phase (P < .001). At lesion-by-lesion analysis, the arterial phase scans depicted significantly more lesions (483 of 536 [90%]) than the portal venous phase (329 of 536 [61%]) and nonenhanced (265 of 465 [57%]) scans (P < .001 for both comparisons). In addition, on arterial phase scans, 386 of 483 lesions, as compared with 134 of 329 lesions on portal venous phase scans (P < .001), were judged to have an enhancement pattern suggestive of infection. The CT phases did not differ significantly in terms of the conspicuity of detected lesions. In patients suspected of having hepatic fungal infection, arterial phase CT depicts significantly more hepatic lesions than does CT performed during the other phases, and it reveals more lesions with enhancement patterns suggestive of infection. Arterial phase CT should be performed in addition to portal venous phase CT in patients suspected of having hepatic fungal infection.

Small gastrointestinal stromal tumours with focal areas of low attenuation on CT: pathological correlation

To describe the pathology of focal areas of low attenuation in small gastrointestinal stromal tumours on contrast-enhanced computed tomography (CT), and to investigate the association of these areas as predictors of malignant potential. Contrast-enhanced helical CT images were obtained of 39 small (up to 5 cm) gastrointestinal stromal tumours. Focal areas of low attenuation were retrospectively evaluated and correlated with histopathological findings. The relation between the mitotic rate of and the presence of focal areas of low attenuation in the tumours was analyzed using Fisher's exact test. Of the 39 small gastrointestinal stromal tumours, 15 contained focal areas of low attenuation on CT. These were found to be due to solid tumour (n=5), haemorrhage (n=3), haemorrhage with necrosis (n=2), cystic degeneration (n=2), fluid in ulcer (n=2), and fibrous septum (n=1); they were not found to be associated with a high mitotic rate (p=0.45). Focal areas of low attenuation on CT in small gastrointestinal stromal tumours represent varying pathological conditions and do not predict malignant potential.