Splenic findings in patients with acute babesiosis.

PURPOSE: To identify the imaging manifestations of splenic involvement in babesiosis, a potentially fatal tick-borne zoonosis with multi-organ involvement. METHODS: In our single center HIPAA compliant IRB-approved study, we performed a retrospective search of the electronic medical record at our institution to identify all patients with known or suspected acute babesiosis from 2000 to 2017. We then reviewed all abdominal imaging of patients with confirmed disease to identify incidence and characteristics of splenic involvement. Splenomegaly was determined using a height- and gender-adjusted reference. RESULTS: After exclusions, 63 patients with a confirmed diagnosis of babesiosis and contemporaneous imaging of the spleen were included in the final cohort. Within this cohort, 56 (89%) had splenomegaly at a minimum and 13 had splenic infarcts. Splenic rupture was present in eight patients with three having a pseudoaneurysm. In 14 patients with follow-up imaging, the spleen subsequently diminished in size. One additional patient with ruptured spleen underwent emergency splenectomy prior to imaging. CONCLUSION: Although the literature suggests splenic involvement is a rare finding, acute parasitemia with babesiosis commonly affects the spleen. Recognition of this association can aid radiologists diagnosing splenic involvement in babesiosis and can lead to appropriate intervention in the minority with splenic hemorrhage.

Apparent diffusion coefficient as a non-invasive predictor of treatment response and recurrence in locally advanced rectal cancer.

AIM: To evaluate the role of pretreatment apparent diffusion coefficient (ADC) as a predictor of treatment response and local recurrence in patients with locally advanced rectal cancer who underwent neoadjuvant therapy. MATERIALS AND METHODS: Forty-nine patients who underwent preoperative diffusion-weighted magnetic resonance imaging (MRI) followed by neoadjuvant chemoradiation and surgery were enrolled in the study. The mean tumour ADC was measured independently from multiple, non-overlapping regions of interest (ROIs) to cover the entire tumour area on a single section by two radiologists and patients were followed postoperatively for a median of 16.4 months. Diagnostic accuracy of ADC for predicting treatment response and recurrence was evaluated using the area under the receiver-operating characteristic (ROC) curve, sensitivity, specificity, and predictive values. Univariate and multivariate analyses including clinical tumour (cT) staging, carcinoembryonic antigen (CEA) level, lymph-node involvement, tumour grade, surgical margin, vascular involvement, and ADC were performed with respect to recurrence. Interobserver agreement of ADC values was assessed. RESULTS: Twenty patients showed response to neoadjuvant therapy and recurrence was noted in 17 patients. Low pretreatment ADC, MRI findings of cT4 staging, and node involvement were significantly related to poor treatment response. Sensitivity and specificity of ADC = 0.833 × 10(-3) mm(2)/s for prediction of treatment response was 75 and 48% for reader 1 and 65 and 52% for reader 2, respectively. Univariate and multivariate analyses identified pretreatment tumour ADC as the only predictive factor for recurrence. Sensitivity and specificity of ADC = 0.833 × 10(-3) mm(2)/s for prediction of recurrence was 86 and 77% for reader 1 and 80 and 69% for reader 2, respectively. Interobserver agreement for measuring ADC was good with a kappa value of 0.70. CONCLUSION: Pretreatment rectal tumour ADC values may be an early biomarker for predicting treatment response and local recurrence in patients who underwent neoadjuvant chemoradiation.

Omental infarct: CT imaging features.

BACKGROUND: The aim of this study is to describe contrast-enhanced computed tomographic (CT) features of acute omental infarction and to study the evolutionary changes on follow-up CT imaging. METHODS: Fifteen cases of omental infarction were evaluated for their initial CT imaging features. The imaging features evaluated included size of the fatty lesion, location, peripheral rim, and relation to colon. CT findings were correlated with etiology, clinical presentation, and leukocytosis. Follow-up CT images were available in eight patients and the imaging features were studied. RESULTS: Eight omental infarcts were of unknown etiology and seven were secondary to abdominal surgery. In 53% of patients (eight of 15), the location of the omental infarct was in the right lower, mid, or upper quadrants. These eight right-side infarcts occurred in six patients with primary omental infarcts. In 13 of 14 patients who underwent CT within 15 days of onset of omental infarct, the margin of the lesion was ill defined. Primary omental (n = 8) infarcts were seen in younger patients (p = 0.02) and were larger on CT (p = 0.02) compared with secondary omental infarcts. CT findings evolved from an ill-defined, heterogeneous fat-density lesion to a well-defined, heterogeneous fat-density lesion with a peripheral hyperdense rim in all six secondary omental infarctions for which acute stage and follow-up CT images were available for interpretation. CONCLUSION: There is a significant difference in the age distribution and CT findings in terms of size of the omental infarction between primary and secondary etiologies. On follow-up CT, secondary omental infarcts progressively shrank and developed a well-defined, hyperdense rim around a fatty core.

Intraductal papillary mucinous tumors of the pancreas.

Intraductal papillary mucinous tumor (IPMT) is an uncommon pancreatic neoplasm with characteristic histology and distinctive clinicobiologic behavior. It is characterized by proliferation of ductal epithelium associated with ductal dilatation and variable mucin production. Due to indolent nature of these tumors, IPMTs are frequently missed or misdiagnosed. Prompt recognition and differentiation from other tumors are essential because IPMT has a better prognosis than other pancreatic malignancies. The purpose of this article is to display the radiologic spectrum of IPMT.

Comparison of excretory phase, helical computed tomography with intravenous urography in patients with painless haematuria.

AIM: To compare excretory phase, helical computed tomography (CT) with intravenous (IV) urography for evaluation of the urinary tract in patients with painless haematuria. MATERIALS AND METHODS: Ninety-one out-patients had IV urography followed by helical CT limited to the urinary tract. Both IV urograms and CT images were evaluated for abnormalities of the urinary tract in a blinded, prospective manner. The clinical significance of abnormalities was scored subjectively and receiver operator characteristic curve analysis was performed. RESULTS: In 69 of 91 patients (76%), no cause of haematuria was identified. In 22 of 91 patients (24%), the cause of haematuria was identified as follows: transitional cell cancer of the bladder (n=15), urinary tract stones (n=3), cystitis (n=2), haemorrhagic pyelitis (n=1) and benign ureteral stricture (n=1). With IV urography, there were 15 true-positive, seven false-negative and three false-positive interpretations. With CT, there were 18 true-positive, four false-negative and two false-positive interpretations. There was no significant difference between IV and CT urography for the significance of the positive interpretations (n=0.47). CONCLUSION: Excretory phase CT urography was comparable with IV urography for evaluation of the urinary tract in patients with painless haematuria. However, the study population did not include any upper tract cancers.

Thorotrast-induced cholangiocarcinoma: case report.

Thorotrast, a contrast medium used extensively before being banned in 1950s, delivers a densely ionizing, high linear energy transfer type of radiation that predisposes to malignancies. We report a case of peripheral cholangiocarcinoma and describe its computed tomographic and magnetic resonance imaging features in a patient who developed it 48 years after exposure to Thorotrast.

Predictive value of benign percutaneous adrenal biopsies in oncology patients.

PURPOSE: Percutaneous CT guided biopsy is accepted as a safe procedure for the diagnosis of indeterminate adrenal masses in oncologic patients. The purpose of this study was to evaluate the accuracy of a 'negative for tumour' adrenal biopsy in the oncologic patient population by assessing subsequent outcome including clinical course, size and imaging characteristics of the adrenal lesions on follow-up imaging studies and pathological findings at re-biopsy or following adrenal mass resection. MATERIALS AND METHODS: Retrospective analysis of 225 oncological patients (FM, 128;87; age range 33-87 years, mean age 66 years) who had undergone CT guided biopsies of an adrenal mass over a 5-year period was performed. Those patients with a report consistent with 'negative for malignancy' were evaluated by reviewing the medical records for patient demographics, primary malignancy, histology of adrenal tumour, subsequent surgical interventions, repeat adrenal biopsy under image guidance, by open surgery or at autopsy, subsequent abdominal imaging in which the adrenal gland was imaged, and long-term outcome including hospital admissions, or death. RESULTS: Of the 225 CT-guided adrenal biopsies performed, 41 (18%) were negative for neoplasm. The primary neoplasm in these 41 patients included lung cancer (n=32), breast (n=5), renal cell carcinoma (n=2), bladder (n=1), and prostate (n=1). The size of the adrenal lesions ranged from 2.8-5 cm. Of the 41 biopsies, which were negative for tumour; 10 were identified as adenomas and the rest showed benign adrenal cortical cells or hyperplasia on cytopathology and histopathology. Repeat biopsies were obtained in 13/41 (31%) patients; whereas 2/41 (5%) had their adrenal gland analyzed on post mortem examination. None of these 15 repeat evaluations yielded tumour. CONCLUSION: In oncological patients, pathological analysis of tissue samples obtained by CT-guided percutaneous biopsy, suggesting benign aetiology, is reliable and predicts a benign course on long-term follow-up. A negative or benign pathology result for a CT guided percutaneous adrenal biopsy can be regarded as a true negative evaluation in oncological patients with no necessity to repeat the biopsy.

Splenic imaging with ultrasmall superparamagnetic iron oxide ferumoxtran-10 (AMI-7227): preliminary observations.

PURPOSE: Ferumoxtran-10 (ultrasmall superparamagnetic iron oxide; Combidex, AMI-7227) is a long-circulating MR contrast agent with reticuloendothelial uptake known to enhance tissue T1 and T2 relaxation rates. The purpose of this study was to assess the effect of ferumoxtran-10-enhanced MRI in evaluating focal splenic lesions. METHOD: Eighteen patients underwent MR evaluation of the spleen. Two of these patients with exophytic normal splenic tissue (splenules) and 13 of these patients with 24 focal splenic lesions (7 cysts, 2 hemangiomas, 7 metastases, 1 infarct, 7 lymphoma) were assessed by T1-weighted gradient echo and T2-weighted fast SE MRI following intravenous administration of ferumoxtran-10 (1.1 mg of Fe/kg). Qualitative analysis involving improved lesion detection and/or characterization, additional information from postcontrast images affecting staging, and patient management was performed. Quantitative measurements of lesion-to-spleen contrast-to-noise ratio were also performed. RESULTS: Additional information was provided by ferumoxtran-10-enhanced images in 15 of 18 patients. In 8 of 15 (53%) patients, improved lesion detection (i.e., number of lesions) was obtained on contrast-enhanced images. Improved lesion visualization (i.e., conspicuity) was noted in 11 of 15 (73%) of patients. In 10 of 15 (67%) patients, postcontrast imaging provided additional information leading to lesion characterization. Staging of disease and patient management were affected in 5 of 15 (33%) and 6 of 15 (40%) patients, respectively. CONCLUSION: Ferumoxtran-10 is a promising contrast agent for the evaluation of focal splenic lesions.

MRI contrast agents for evaluating focal hepatic lesions.

Contrast-enhanced magnetic resonance imaging (MRI) has become an important tool in the detection and characterization of focal hepatic lesions especially when other investigations such as ultrasound (US) and computed tomography (CT) are inconclusive. The purpose of this pictorial review is to briefly summarize the properties of various MRI contrast agents used in hepatic imaging and to highlight their role in evaluation of focal hepatic lesions.

Nonvascular interventional procedures: analysis of a 10-year database containing more than 21,000 cases.

PURPOSE: To analyze all procedures performed during 10 years in a nonvascular interventional practice. MATERIALS AND METHODS: Date, organ location, and type of all 21,324 procedures performed between October 1990 and September 2000 were recorded in a database; also included were patient age and inpatient or outpatient status. Because genitourinary procedures were not included during the first 4 years, nephrostomies were added retrospectively. Yearly interventional caseload was compared with the department caseload and the assignment of new medical record numbers. Trends in individual procedure location and type were analyzed, as well as patient age, inpatient status, daily caseloads, and day of the week when the procedure was performed. RESULTS: Caseloads have increased 10.8% per year, exceeding increases in radiology department and hospital activity. Abdomen, outside of a specific organ, was the most common location; catheter deployment was the most common procedure. Abscess drainage, placement of chest tubes, and nephrostomies have increased, but biliary drainages have decreased. Inpatients outnumbered outpatients in all years except 1995, but the trend was toward an increase in the proportion of outpatients. The average patient was 59.6 years old, with average age diminishing. Friday was the busiest day, but weekend procedures have increased. CONCLUSION: Nonvascular interventional procedures have increased, with more currently being performed on weekends.

Tunneled peritoneal catheter placement under sonographic and fluoroscopic guidance in the palliative treatment of malignant ascites.

OBJECTIVE: We present a treatment for recurrent, symptomatic ascites in patients with malignant disease. This report summarizes our experience with percutaneous tunneled peritoneal catheters in 24 patients. SUBJECTS AND METHODS: Of the 40 consecutive patients who presented with at least four therapeutic paracenteses in a 4-week period, 24 patients underwent the percutaneous tunneled procedure. All had malignant ascites. RESULTS: All 24 patients had successful insertion of a permanent tunneled peritoneal drainage catheter. Eighteen were outpatients and six were inpatients. All patients were relieved of their clinical symptoms, including abdominal distention and dyspnea, and were relieved of lower extremity discomfort. The mean life span after catheter placement was 7.2 weeks. Twenty (83%) of the 24 patients were treated at home with their catheters in place. Three patients experienced minor complications from bacterial peritonitis, which responded to antibiotics. One patient had to have his catheter removed. CONCLUSION: Percutaneous placement of specialized tunneled catheters appears to be a viable and safe technique in patients who have symptomatic ascites that require frequent therapeutic paracentesis for relief of symptoms.

CT colonography with teleradiology: effect of lossy wavelet compression on polyp detection--initial observations.

PURPOSE: To assess the consequences of lossy compression on the diagnostic accuracy of CT colonography for detecting colonic polyps. MATERIALS AND METHODS: Helical CT images of cleansed colonic segments were evaluated. Source images were compressed to 1:1, 10:1, and 20:1 ratios with lossy wavelet compression. Two independent readers blinded to corresponding colonoscopic results analyzed 144 randomly ordered colonic segments in multiplanar and volume-rendered endoscopic views. Sensitivity, specificity, and receiver operating characteristic curves were generated for each compression ratio on the basis of expressed confidence in lesion presence. Similar analyses were performed to assess distention and bowel preparation adequacy and evaluation time required. RESULTS: Results based on video colonoscopy-confirmed lesions revealed 100% (four of four) sensitivity for lesions larger than 10 mm for compression ratios 1:1, 10:1, and 20:1 for both readers; sensitivities for all lesions smaller than 10 mm were 50%-78%, 38%-67%, and 38%-67% for respective ratios for both readers. Differences in diagnostic performance for each reader across ratios were not significant (P =.30-.99, McNemar test). The time required to evaluate and assess bowel preparation and distention adequacy did not change significantly across ratios. CONCLUSION: On the basis of the patient sample, lossy compression of transverse source images to at least a 20:1 ratio did not adversely affect diagnostic performance or evaluation time for CT colonography.

Dual contrast enhanced magnetic resonance imaging of the liver with superparamagnetic iron oxide followed by gadolinium for lesion detection and characterization.

AIM: Iron oxide contrast agents are useful for lesion detection, and extracellular gadolinium chelates are advocated for lesion characterization. We undertook a study to determine if dual contrast enhanced liver imaging with sequential use of ferumoxides particles and gadolinium (Gd)-DTPA can be performed in the same imaging protocol. MATERIALS AND METHODS: Sixteen patients underwent dual contrast magnetic resonance imaging (MRI) of the liver for evaluation of known/suspected focal lesions which included, metastases (n = 5), hepatocellular carcinoma (HCC;n = 3), cholangiocharcinoma(n = 1) and focal nodular hyperplasia (FNH;n = 3). Pre- and post-iron oxide T1-weighted gradient recalled echo (GRE) and T2-weighted fast spin echo (FSE) sequences were obtained, followed by post-Gd-DTPA (0.1 mmol/kg) multi-phase dynamic T1-weighted out-of-phase GRE imaging. Images were analysed in a blinded fashion by three experts using a three-point scoring system for lesion conspicuity on pre- and post-iron oxide T1 images as well as for reader's confidence in characterizing liver lesions on post Gd-DTPA T1 images. RESULTS: No statistically significant difference in lesion conspicuity was observed on pre- and post-iron oxide T1-GRE images in this small study cohort. The presence of iron oxide did not appreciably diminish image quality of post-gadolinium sequences and did not prevent characterization of liver lesions. CONCLUSION: Our results suggest that characterization of focal liver lesion with Gd-enhanced liver MRI is still possible following iron oxide enhanced imaging.Kubaska, S.et al. (2001). Clinical Radiology, 56, 410-415

Transvaginal interventional procedures: aspiration, biopsy, and catheter drainage.

Transvaginal ultrasonographically (US) guided procedures are simple and safe and often represent the only means of access to pelvic disease. Aspiration of cystic pelvic masses and core biopsy of solid pelvic masses can be easily performed by using the transvaginal route, an endoluminal US transducer, and a needle guide. Because of concerns about false-negative diagnosis and potential tumor seeding with biopsy of primary ovarian cystic lesions, the indications for transvaginal aspiration and biopsy of ovarian and adnexal lesions are predominantly therapeutic. Similarly, using an endoluminal probe with modification of the guide, one can also perform safe and effective trocar catheter drainage of pelvic abscesses via the transvaginal route. The transvaginal route is ideally suited to pelvic abscess drainage because of the proximity of the vaginal fornices to most pelvic fluid collections. The transvaginal route has the disadvantage of being semisterile; because of the risk of superinfecting previously noninfected pelvic pathologic conditions, the transvaginal approach should be used only for solid lesions or cystic lesions that can be completely aspirated. Familiarity with the transvaginal route of access is crucial for adequate treatment of many gynecologic and nongynecologic pelvic pathologic conditions.

Complications after pancreatoduodenectomy: imaging and imaging-guided interventional procedures.

Over the past decade, performance of the Whipple procedure, or pancreatoduodenectomy, to treat both malignant and benign disease has increased. This increase is in large part due to the decreasing perioperative mortality rate, which is down from historic highs of 25% to the 1.0%--1.5% now achieved in large centers. Although advances in surgical management have improved the outlook for patients undergoing pancreatoduodenectomy, the improving mortality rate is also in part attributed to improvements over the past 2 decades in cross-sectional imaging and imaging-guided interventional procedures. Although the mortality rates have improved, the morbidity, or rate of complications, has remained relatively constant. Contributions by radiologists in both diagnosis and treatment of complications are crucial in certain patients with postpancreatoduodenectomy abdominal abscesses, bilomas, liver abscess, and biliary obstruction. Familiarity with normal variations in the postoperative appearance of the upper abdomen, awareness of pitfalls in interpretation, and knowledge of the available imaging-guided interventions will facilitate recognition of postpancreatoduodenectomy complications and allow prompt triage of patients to imaging-guided interventions.

Comprehensive evaluation of patients with haematuria on multi-slice computed tomography scanner: protocol design and preliminary observations.

An imaging protocol with a multi-slice CT scanner that allows comprehensive assessment of patients with haematuria is described. This protocol allows evaluation of the kidneys, ureters and bladder in a single examination using CT. This approach should streamline the diagnostic work-up of patients with haematuria.

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.

The clinical value of ferric ammonium citrate: a positive oral contrast agent for T1-weighted MR imaging of the upper abdomen.

This study was undertaken to determine whether ferric ammonium citrate (FAC), a positive magnetic resonance (MR) contrast agent, is of clinical value in demonstrating or excluding pathology of the upper gastrointestinal tract. A retrospective review was performed of pre- and post-FAC studies of MR examinations in 203 patients from phase II and III clinical trials in whom final diagnoses had been established based on the results of biopsy, surgery, or independent imaging procedures. Two independent reviewers made randomized and blinded assessments of the stomach, duodenum, and pancreas. FAC significantly increased the certainty of diagnosis for normal studies of the stomach and duodenum for both readers (P < 0.001) and for abnormal studies of the stomach for one reader (P = 0.004). FAC also significantly increased the certainty of diagnosis for normal pancreas for one reader (P < 0.001). FAC significantly (P < 0.001) increased accuracy and specificity for diagnoses involving the stomach and duodenum for both readers and for one reader for the pancreas. There was significant improvement in sensitivity for gastric diagnoses (P = 0.013) for one reader but not for the duodenum or pancreas. We conclude that FAC is helpful in demonstrating and excluding upper gastrointestinal pathology on MR.