Post-operative assessment in patients after liver transplantation: imaging parameters associated with 1-year graft failure.

PURPOSE: To identify post-liver transplant CT findings which predict graft failure within 1 year. MATERIALS AND METHODS: We evaluated the CT scans of 202 adult liver transplants performed in our institution who underwent CT within 3 months after transplantation. We recorded CT findings of liver perfusion defect (LPD), parenchymal homogeneity, and the diameters and attenuations of the hepatic vessels. Findings were correlated to 1-year graft failure, and interobserver variability was assessed. RESULTS: Forty-one (20.3%) of the 202 liver grafts failed within 1 year. Graft failure was highly associated with LPD (n = 18/25, or 67%, versus 15/98, or 15%, p < 0.001), parenchymal hypoattenuation (n = 20/41, or 48.8% versus 17/161, or 10.6%, p < 0.001), and smaller diameter of portal veins (right portal vein [RPV], 10.7 ± 2.7 mm versus 14.7 ± 2.2 mm, and left portal vein [LPV], 9.8 ± 3.0 mm versus 12.4 ± 2.2 mm, p < 0.001, respectively). Of these findings, LPD (hazard ratio [HR], 5.43, p < 0.001) and small portal vein diameters (HR, RPV, 3.33, p < 0.001, and LPV, 3.13, p < 0.05) independently predicted graft failure. All the measurements showed fair to moderate interobserver agreement (0.233~0.597). CONCLUSION: For patients who have CT scan within the first 3 months of liver transplantation, findings of LPD and small portal vein diameters predict 1-year graft failure. KEY POINTS: •Failed grafts are highly associated with liver perfusion defect, hypoattenuation, and small portal vein. •Right portal vein < 11.5 mm and left portal vein < 10.0 mm were associated with poor graft outcome. •Liver perfusion defect and small portal vein diameter independently predicted graft failure.

Appearance and Frequency of Gas Interface Artifacts Involving Small Bowel on Rapid-Voltage-Switching Dual-Energy CT Iodine-Density Images.

OBJECTIVE: The purpose of this study is to describe the appearance and frequency of gas interface artifacts in the jejunum that may mimic severe bowel disease on iodine-density images generated from rapid-voltage-switching dual-energy CT (DECT) scans. MATERIALS AND METHODS: Two readers retrospectively reviewed 108 consecutive abdominal rapid-voltage-switching DECT scans to record the presence of image artifacts in jejunal segments with different degrees of gaseous luminal filling, classified as full, partial, or absent. Readers viewed iodine-density images and corresponding 140-kVp and 65-keV virtual monochromatic images and classified the jejunal artifacts on iodine-density images as pseudostratified appearance of the bowel wall, pseudopneumatosis, pseudohyperenhancement, or pseudohypoenhancement. We correlated the presence of the artifacts with clinical features suggesting bowel disease. RESULTS: Image artifacts were found in 91 of 108 scans (84.3%), appeared in 148 of 265 jejunal segments (55.8%), and included each type except for pseudohypoenhancement. Artifacts occurred exclusively when gas was present in the bowel lumen and were seen in 59 of 59 (100%) fully gas-distended segments, 89 of 98 (90.8%) partially gas-distended segments, and none of 108 gas-absent segments (p < 0.0001). In fully and partially gas-distended jejunal segments (n = 157), 148 (94.3%) segments had two or more artifacts. None of the patients was found to have clinical bowel-related injury on follow-up of medical records. CONCLUSION: Pseudostratified appearance, pseudopneumatosis, and pseudohyperenhancement, but not pseudohypoenhancement, artifacts are common in gas-filled jejunal segments on iodine-density images generated from rapid-voltage-switching DECT scans and are not seen in the corresponding 140-kVp or 65-keV images. Knowledge of the appearance of such iodine-density image artifacts will avoid potential examination interpretation pitfalls.

CT Findings for Detecting the Presence of Gangrenous Ischemia in Cholecystitis.

OBJECTIVE: The objective of our study was to evaluate the diagnostic accuracy of CT in differentiating gangrenous cholecystitis from uncomplicated cholecystitis and healthy gallbladders. MATERIALS AND METHODS: We performed a retrospective review of 308 patients with histologically proven gangrenous cholecystitis who underwent preoperative CT 1 month before gallbladder removal over a 4-year period. Two readers who were blinded to the histologic diagnosis independently recorded CT features of and overall likelihood of gangrenous cholecystitis on a 5-point scale (1, definitely absent; 5, definitely present). Ratings were dichotomized such that a diagnosis was considered present at a rating of 4 or 5 and considered absent at lower ratings. Interobserver variability for individual CT findings was also assessed. RESULTS: Patients had gangrenous cholecystitis (n = 28), acute cholecystitis (n = 98), chronic cholecystitis (n = 118), or healthy gallbladders (n = 64). Multivariate analysis showed that CT findings of gallbladder distention greater than 4.0 cm (odds ratio [OR], 9.63; p < 0.01), mural striation (OR, 11.39; p < 0.01), and decreased mural enhancement (OR, 3.55; p < 0.05) independently predicted gangrenous cholecystitis. Using these CT features, the diagnosis of gangrenous cholecystitis was made with a specificity of 93.9% and 89.6% for readers 1 and 2, respectively, and accuracy of 90.9% and 87.0%, respectively. Good agreement was seen between the two readers with respect to gallbladder distention greater than 4.0 cm (κ = 0.77) and decreased mural enhancement (κ = 0.64). CONCLUSION: A markedly distended gallbladder associated with decreased wall enhancement is highly specific for gangrenous cholecystitis.

Transient respiratory motion artifact during arterial phase MRI with gadoxetate disodium: risk factor analyses.

OBJECTIVE: The purpose of this article is to identify risk factors for arterial phase respiratory motion artifact in gadoxetate disodium-enhanced liver MRI. MATERIALS AND METHODS: We retrospectively identified 220 consecutive patients who underwent 357 MRI examinations, including 68 patients who underwent multiple MRI examinations, with gadoxetate disodium between 2010 and 2013. The arterial phase timing was determined by a fluoroscopic-triggering method. T1-weighted unenhanced and contrast-enhanced images were reviewed to record respiratory motion artifact, which was graded on a 5-point scale. Arterial phase transient severe motion was considered to be present if the motion score was 4 or greater on the arterial phase images and if the motion scores were 2 or less on unenhanced and other contrast-enhanced images. Patient characteristics and risk factors (e.g., age, sex, weight, body mass index, medical and radiologic history, allergy to MRI and iodinated contrast agents, estimated glomerular filtration rate, Child-Pugh class, and findings on current MRI examinations) were recorded. We included a history of transient severe motion on prior MRI as a predictor variable. We performed univariable and multivariable analysis using the generalized estimated equations to adjust for clustering. RESULTS: The incidence of transient severe motion was 12.9% (46/357). On univariable analysis, a history of transient severe motion (odds ratio [OR] = 3.31; p = 0.04) on prior MRI and allergy to iodinated contrast agent (OR = 3.03; p = 0.01) statistically significantly increased the incidence of transient severe motion for a given MRI examination. These associations were not seen on multivariable analysis (adjusted OR = 2.38 and p = 0.23 for a history of transient severe motion; adjusted OR = 1.93 and p = 0.23 for allergy to CT contrast agent). CONCLUSION: The occurrence of transient severe motion during arterial phase MRI with gadoxetate disodium is 12.9% and is poorly predicted on the basis of risk factors.

Prevalence of abdominal aortic calcifications in older living renal donors and its effect on graft function and histology.

We assessed the prevalence of abdominal aortic calcification (AAC) in older living kidney donors and its effect on recipient eGFR and graft histology. A total of 292 consecutive living pairs with donor age ≥50 from 2003 to 2013 were identified (mean age 56; range 50-78; F/M: 1.8). Donor AAC was determined by prenephrectomy unenhanced CT. Recipient eGFR and spot urine protein: creatinine ratios (UPCRs) were recorded. A total of 180 recipients had 6-month protocol biopsies. AAC was present in 40.7% of donors, and they were older (58.6 versus 54.7 years old, P < 0.0001) and more likely to be male (77.6% vs. 37.3%, P = 0.004). There was no significant difference in eGFR or spot UPCR up to 36 months in recipients of allografts from donors with versus without AAC. At 6-month biopsy, there was a higher percentage of allografts with vascular fibrous intimal thickening and arteriolar hyaline thickening from donors with versus without AAC (vascular fibrous intimal thickening: 38.8% vs. 7.1% and arteriolar hyaline thickening: 35.8% vs. 7.1%; P < 0.001 for both). The presence of donor AAC predicts the presence of vascular disease [vascular fibrous intimal thickening (OR: 7.2; CI:2.9-17.9) and arteriolar hyaline thickening (OR:5.7; CI:2.3-14.1)] in allografts at 6 months. Donor AAC is predictive of renal vascular disease and may help to improve the screening of potential donors and inform post-transplant management.

Combination therapy of focused ultrasound and radio-frequency for noninvasive body contouring in Asians with MRI photographic documentation.

Previous studies have shown that single or multiple treatments by focused ultrasound are effective and safe. However, most include focused ultrasound only and not radio-frequency treatment. There is paucity of magnetic resonance imaging (MRI) measurements and pictures in the literature. This study aimed to assess the efficacy, safety, and pain and satisfaction levels of the combination therapy of focused ultrasound and radio-frequency for improving body contours. Thirty-two Asian patients received 3 sequential treatments every 2 weeks in the abdominal region. Safety parameters and adverse events were recorded. The subjects' pain and satisfaction levels were evaluated using a five-point Likert scale. Two patients underwent MRI study randomly. There was a mean reduction in circumference of 3.91 ± 1.8 cm (p ≤ 0.001). In MRI measurement, the average in fat thickness reduction was 21.4 and 25% on the upper and lower abdomen, respectively. There were three mild and self-limited localized adverse events. The satisfaction survey showed that 71.9% was satisfied with the results, while pain level evaluation showed that 90.5% felt no pain. Combination therapy of focused ultrasound and radio-frequency for noninvasive body contouring is an effective, safe, and painless procedure in Asians. Although the change is minor compared to traditional surgical procedure, it is real, definite, and effective.

Case Report: Radiographic Identification of Intrapleural Misplacement of Epidural Catheter in an Intubated Post-Lung Transplant Patient.

Intrapleural misplacement of epidural catheter is a rare complication of thoracic epidural placement, which can be difficult to detect in intubated patients with unreliable pain reports and hemodynamic response to the test dose. We describe a case of intrapleural misplacement of thoracic epidural in a 50-year-old man status-post bilateral lung transplant and highlight the use of radiographic techniques to identify the misplacement.

CT findings of severe burn injuries after a motor vehicle collision: a case report.

Severe burn injuries can complicate management of polytrauma. While CT is the primary imaging modality for evaluation of trauma injuries, CT findings of severe burn are rarely reported. A 31-year-old female was brought to the emergency department after motor vehicle collision in which she sustained a burn injury from contact with the vehicle muffler. Her initial trauma workup was notable for full-thickness burns to her left abdominal wall among other injuries. CT scan showed skin thickening and extensive stranding involving the whole layer of subcutaneous soft tissue. The deep fascia and underlying muscle layer were free from burn injuries. Identification of this finding on the CT scan helps establish appropriate care.

The Role of Noncontrast CT in the Evaluation of Surgical Abdomen Patients.

Acute surgical abdomen is commonly encountered in the ED and CT is widely used as an informative diagnostic tool to evaluate potential surgical indications. However, the adverse effects of contrast material used in CT scanning have been documented. We sought to delineate the role of noncontrast CT in the evaluation of patients with acute surgical abdomen. Between August 2015 and December 2015, patients with nontraumatic surgical abdomen who underwent preoperative CT were enrolled in the current study. The patients for whom the CT results permitted surgical decision-making were the focus of this study. The disease entities included acute appendicitis, acute cholecystitis, hollow organ perforation, mechanical bowel obstruction, intra-abdominal abscess that could not be drained percutaneously, and ischemic bowel disease. The results of contrast-enhanced and noncontrast CT were compared and analyzed. The surgical conditions identifiable by noncontrast CT were recorded. In total, 227 patients were enrolled in the study. In 90.7 per cent of patients overall, the findings indicating the need for surgical treatment were visualized on both the noncontrast and contrast-enhanced images (acute appendicitis: 89.3%, acute cholecystitis: 89.7%, hollow organ perforation: 97.4%, bowel obstruction: 100%, intra-abdominal abscess: 100%, and ischemic bowel disease: 55.6%). Noncontrast CT provides benefit for critical decision-making. Body mass index may affect the accuracy of noncontrast imaging in the evaluation of patients with surgical abdomen. In some specific situations, contrast enhancement remains necessary.

Comparison of hepatocellular carcinoma conspicuity on hepatobiliary phase images with gadoxetate disodium vs. delayed phase images with extracellular cellular contrast agent.

OBJECTIVE: To compare the conspicuity of hepatocellular carcinoma (HCC) on hepatobiliary phase of gadoxetate disodium-enhanced vs. delayed phase of gadodiamide-enhanced MR images, relative to liver function. METHODS AND MATERIALS: We retrospectively identified 86 patients with newly diagnosed HCC between 2010 and 2013 and recorded the severity of liver disease by Child-Pugh class (CPC). 38 patients had gadodiamide-enhanced 5-min delayed and 48 had gadoxetate disodium-enhanced 20-min delayed hepatobiliary MR images. The conspicuity of 86 HCCs (mean size, 2.7 cm) was graded visually on a 3-point scale and quantified by liver-to-tumor contrast ratios (LTC). The relative liver parenchymal enhancement (RPE) was measured. For different CPCs, we compared the conspicuity of HCC and RPE between gadodiamide and gadoxetate. RESULTS: In patients with CPC A, the visual conspicuity and LTC of the 27 HCCs imaged with gadodiamide were significantly lower than those of the 38 HCCs with gadoxetate (P < 0.01, <0.01, respectively). RPE was lower in gadodiamide scans than gadoxetate scans (P < 0.01). Conversely, in patients with CPC B and C, HCCs appeared more frequently as definite hypointensity when imaged with gadodiamide (72.7%, 8/11) than gadoxetate (20%, 2/10, P = 0.03). LTC (mean 18.1 vs. 7.5, P = 0.04) and RPE (mean 75.5 vs. 45.4, P = 0.04) was significantly higher in the gadodiamide than gadoxetate scans. CONCLUSION: In patients with compromised liver function, hypointensity of HCC is more conspicuous in the gadodiamide delayed phase than the gadoxetate hepatobiliary phase. This likely reflects the high extracellular accumulation of gadodiamide and poor hepatocyte uptake of gadoxetate in patients with compromised liver function.

Troubleshooting Arterial-Phase MR Images of Gadoxetate Disodium-Enhanced Liver.

Gadoxetate disodium is a widely used magnetic resonance (MR) contrast agent for liver MR imaging, and it provides both dynamic and hepatobiliary phase images. However, acquiring optimal arterial phase images at liver MR using gadoxetate disodium is more challenging than using conventional extracellular MR contrast agent because of the small volume administered, the gadolinium content of the agent, and the common occurrence of transient severe motion. In this article, we identify the challenges in obtaining high-quality arterial-phase images of gadoxetate disodium-enhanced liver MR imaging and present strategies for optimizing arterial-phase imaging based on the thorough review of recent research in this field.

CT-guided core needle biopsy of deep suprahyoid head and neck lesions.

OBJECTIVE: To evaluate the efficacy of computer tomography (CT)-guided core needle biopsy (CNB) in the diagnosis of deep suprahyoid lesions in patients with treated head and neck cancers. MATERIALS AND METHODS: Between December, 2003 and May, 2011, 28 CT-guided CNBs were performed in 28 patients with deep suprahyoid head and neck lesions. All patients had undergone treatment for head and neck cancers. Subzygomatic, paramaxillary, and retromandibular approaches were used. The surgical results, response to treatment, and clinical follow-up were used as the diagnostic reference standards. RESULTS: All biopsies yielded adequate specimens for definitive histological diagnoses. A specimen from a right parapharyngeal lesion showed atypia, which was deemed a false negative diagnosis. Diagnostic accuracy was 27/28 (96.4%). Two minor complications were encountered: a local hematoma and transient facial palsy. Between the 18 or 20 gauge biopsy needles, there was no statistical difference in the diagnostic results. CONCLUSION: CT-guided core needle biopsy, with infrequent and minor complications, is an accurate and efficient method for the histological diagnosis of deep suprahyoid lesions in post-treated head and neck cancer patients. This procedure can preclude an unnecessary surgical intervention, especially in patients with head and neck cancers.

CT-guided core needle biopsy of deep suprahyoid head and neck lesions in untreated patients.

This study aimed to evaluate the efficacy of CT-guided core needle biopsy (CNB) in the diagnosis of deep head and neck tumors in untreated patients. We retrospectively reviewed the records of ten consecutive CT-guided CNB procedures from ten patients without a related history from March 2004 to February 2012. The surgical results, treatment response and clinical follow-up were used as the diagnostic standards. All specimens were considered adequate. Nine out of ten cases matched the final diagnosis. Biopsy failed to diagnose the infratemporal meningioma en plaque in a particular case. Three cases were carcinomas. No complication was encountered. CT-guided core needle biopsy is an efficient and safe technique for histological diagnosis of skull base lesions in patients without a related history. This technique can offer a definite tissue diagnosis and avoid unnecessary surgical interventions for such patients.

Diagnostic efficacy of ultrasonography-guided fine needle aspiration biopsy in evaluating salivary gland malignancy.

BACKGROUND: Salivary gland masses constitute a diagnostic challenge in daily clinical practice and tissue sampling is required to establish a diagnosis. We aimed to evaluate the efficacy of ultrasonography-guided fine needle aspiration biopsy (UGFNAB) in the diagnosis of salivary gland lesions. METHODS: From January 2007 to September 2010, a total of 158 patients who underwent both UGFNAB and surgical excision for salivary gland mass lesions were included in this study. Patients with insufficient sampling or inconclusive cytology diagnosis were excluded from the analysis of diagnostic accuracy of UGFNAB. RESULTS: UGFNAB yielded sufficient sampling for analysis in 137 patients, leading to a diagnostic yield of 86.7%. Among these 137 patients, 24 patients were confirmed to have malignant tumors. The sensitivity, specificity and accuracy of UGFNAB for malignancy were 66.7%, 98.2%, and 92.7%, respectively. No UGFNAB-related complications were encountered. CONCLUSIONS: UGFNAB of salivary gland masses is a safe technique that offers high specificity and accuracy but moderate diagnostic yield and sensitivity.

Great saphenous vein thrombosis causing acute pulmonary embolism suggested by combined CT venography and pulmonary angiography.

Pulmonary embolism is a life-threatening condition, which is most commonly related to deep vein thrombosis. Varicose vein thrombosis, a very common disease, is seldom reported as being related to pulmonary embolism. We present combined computed tomography venography and pulmonary angiography findings suggesting that thrombosed varicosities of a great saphenous vein caused acute pulmonary embolism in a 30-year-old male.