Frank H. Miller

Utility of diffusion‐weighted MRI in distinguishing benign and malignant hepatic lesions

To evaluate apparent diffusion coefficient (ADC) values for characterization of a variety of focal liver lesions and specifically for differentiation of solid benign lesions (focal nodular hyperplasia [FNH] and adenomas) from solid malignant neoplasms (metastases and hepatocellular carcinoma [HCC]) in a large case series.

Videocapsule Endoscopy versus Barium Contrast Studies for the Diagnosis of Crohn's Disease Recurrence Involving the Small Intestine

OBJECTIVES:Historically, suspected Crohns disease (CD) has been evaluated with small bowel follow-through (SBFT) or enteroclysis (equally accurate). This study was undertaken to determine the accuracy of videocapsule endoscopy (VCE) in the diagnosis of CD relative to SBFT and clinical/laboratory indices of CD activity. Previous investigations have used VCE for the diagnosis of suspected CD in patients presenting with a variety of gastrointestinal symptoms. This is the first study to evaluate the occurrence of active disease in patients with known CD.METHODS:Thirty subjects (22 female, 8 male, aged 36.9 ± 14.2 yr); all with prior CD diagnosis made on the basis of standard criteria (5.5 ± 6.5 yr prior to study), in whom recurrent CD was suspected based on abdominal pain, diarrhea, anemia, and/or arthralgias. Subjects were studied in a prospective, blinded evaluation of VCE versus SBFT. SBFT was performed first; those with stricture and proximal bowel dilation were excluded from further study. For SBFT, studies were graded as grade 0 (normal), grade 1 (minimal nodularity, ulcerations, normal luminal diameter, < 5 cm involved), grade 2 (more extensive ulcers, minimal luminal narrowing, 5–10 cm involved), or grade 3 (fistula, skip areas, extensive ulceration, >10 cm involved). VCE was performed within 1 wk of SBFT. Serum was obtained for ESR (erythrocyte sedimentation rate) and CRP (C-reactive protein), stool was obtained for α-1 antitrypsin, and the Harvey Bradshaw index of CD severity was calculated. VCE (digitalized video) was graded as grade 0 (normal), grade 1 (erythema, isolated villi loss), grade 2 (erosion, no ulcer), or grade 3 (ulcers, spontaneous bleeding, and/or stricture).RESULTS:Twelve patients were excluded for small bowel obstruction. VCE and SBFT scores highly correlated (r = 0.65; p = 0.001). Active CD was visualized in 21 of 30 patients with videocapsule endoscopy and in 20 of 30 patients with SBFT. Complete agreement occurred in 13 of 30 studies; 13 of 17 studies differed by one grade. SBFT found mucosal disease in 20 of 30 patients and VCE found mucosal disease in 21 of 30 patients. VCE found mucosal disease in 6 patients (5 in grade 1, 1 in grade 3) with normal SBFT. SBFT showed CD in 5 patients (all grade 1) with normal VCE. Neither VCE nor SBFT scores correlated with biological or clinical indices. Patient satisfaction was superior for VCE.CONCLUSIONS:VCE and SBFT are complementary for the diagnosis of CD. SBFT may be required to detect strictures as the videocapsule may not pass. However, some strictures may also be missed with SBFT. VCE is less invasive, less time-consuming for the patient than SBFT, and avoids radiation exposure, although reading time is greater for the gastroenterologist than the radiologist. Given that patients with clinically suspected CD recurrence may not have active disease, unnecessary and potentially harmful empiric therapy is not warranted without imaging.

Computerized tomographic colonography: Performance evaluation in a retrospective multicenter setting

BACKGROUND & AIMSnNo multicenter study has been reported evaluating the performance and interobserver variability of computerized tomographic colonography. The aim of this study was to assess the accuracy of computerized tomographic colonography for detecting clinically important colorectal neoplasia (polyps >or=10 mm in diameter) in a multi-institutional study.nnnMETHODSnA retrospective study was developed from 341 patients who had computerized tomographic colonography and colonoscopy among 8 medical centers. Colonoscopy and pathology reports provided the standard. A random sample of 117 patients, stratified by criterion standard, was requested. Ninety-three patients were included (47% with polyps >or=10 mm; mean age, 62 years; 56% men; 84% white; 40% reported colorectal symptoms; 74% at increased risk for colorectal cancer). Eighteen radiologists blinded to the criterion standard interpreted computerized tomography colonography examinations, each using 2 of 3 different software display platforms.nnnRESULTSnThe average area under the receiver operating characteristic curve for identifying patients with at least 1 lesion >or=10 mm was 0.80 (95% lower confidence bound, 0.74). The average sensitivity and specificity were 75% (95% lower confidence bound, 68%) and 73% (95% lower confidence bound, 66%), respectively. Per-polyp sensitivity was 75%. A trend was observed for better performance with more observer experience. There was no difference in performance across software display platforms.nnnCONCLUSIONSnComputerized tomographic colonography performance compared favorably with reported performance of fecal occult blood testing, flexible sigmoidoscopy, and barium enema. A prospective study evaluating the performance of computerized tomography colonography in a screening population is indicated.

Response of Liver Metastases After Treatment with Yttrium-90 Microspheres: Role of Size, Necrosis, and PET

OBJECTIVEnYttrium-90 radioembolization is an emerging treatment for liver malignancies. The purpose of this study was to evaluate the imaging response of liver metastases to 90Y microspheres based on size and necrosis criteria using CT and comparing the results to PET and to describe imaging features related to 90Y therapy.nnnMATERIALS AND METHODSnWe reviewed the imaging studies of 42 patients with unresectable liver metastases treated with lobar radioembolization with 90Y. CT response was determined using traditional size criteria (World Health Organization [WHO] and Response Evaluation Criteria in Solid Tumors [RECIST]), necrosis criteria, and combined criteria (RECIST and necrosis). We compared the response on CT with the response on PET. Complications of treatment were assessed.nnnRESULTSnThe response rate was 19% (8/42) by WHO criteria, 24% (10/42) by RECIST, 45% (19/42) by necrosis criteria, and 50% (21/42) by combined criteria. Stabilization of lesion size occurred in 50% of patients. Necrosis and combined criteria identified responders earlier than RECIST and WHO criteria. Seven responders by combined criteria had an increase in lesion size on initial follow-up and would have been considered nonresponders. PET scans were obtained in 23 patients (33 treated lobes). PET detected significantly more responses to treatment (21/33, 63%) than CT using RECIST (2/33, 6%) or combined criteria (8/33, 24%) (p < 0.05, McNemar test). Complications of treatment included radiation cholecystitis (10 patients, 23%) and liver edema (18 patients, 42%).nnnCONCLUSIONnThe use of necrosis and size criteria on CT and correlation with PET may improve the accuracy of assessment of response to 90Y treatment in patients with liver metastases and detect response earlier than standard size criteria.

Imaging benign and malignant disease of the gallbladder

This article reviews the imaging of various benign and malignant diseases of the gallbladder. Clinical findings and imaging features using ultrasound, CT, and MR for the detection and evaluation of gallstones, acute cholecystitis, xanthogranulomatous cholecystitis, adenomyomatosis, and carcinoma of the gallbladder among other disorders are discussed.

Diffusion-weighted MR Imaging for Determination of Hepatocellular Carcinoma Response to Yttrium-90 Radioembolization

Early detection of the response of hepatocellular carcinoma (HCC) to yttrium-90 radioembolization therapy may be important to permit repeat radioembolization or alternative treatment options. Water-mobility measurements with use of diffusion-weighted (DW) magnetic resonance (MR) imaging are useful for noninvasive interrogation of microstructural tissue properties. Findings of DW MR imaging may serve as an early biomarker of HCC response. This study tested the hypothesis that DW MR imaging can detect changes in tumor tissue water diffusion in response to (90)Y therapy. In each of six patients with HCC included in the study, tumor water diffusion increased significantly after therapy. DW MR imaging is a promising technique for noninvasive assessment of tumor response to (90)Y radioembolization.

Imaging of Hepatocellular Carcinoma After Treatment with Yttrium-90 Microspheres

OBJECTIVEnYttrium-90 radioembolization is an emerging therapy for unresectable hepatocellular carcinoma (HCC). Although therapeutic response based on size has been evaluated in numerous studies, necrosis has been used as a criterion of response in only a few studies. The purpose of our study was to describe the imaging features of HCC after 90Y treatment and to compare size criteria (World Health Organization [WHO] and Response Evaluation Criteria in Solid Tumors [RECIST]) with necrosis criteria and combined criteria (RECIST and necrosis) for assessment of response.nnnMATERIALS AND METHODSnCT images of 42 patients with 76 90Y-treated HCC lesions were analyzed. We used four response criteria: WHO size, RECIST size, necrosis, and combined criteria (RECIST and necrosis). Imaging features of treated lesions included both nodular and peripheral rim enhancement. Survival was assessed with the Kaplan-Meier method.nnnRESULTSnThe response rate was 23% according to RECIST criteria, 26% according to WHO criteria, 57% according to necrosis criteria, and 59% according to combined criteria. Response according to necrosis and combined criteria was detected earlier than response according to size criteria alone. Ten responding lesions initially increased in size. After therapy, enhancing peripheral nodules increased in size in 10 lesions, decreased in size in two lesions, and disappeared in two lesions. Twenty-one of 25 lesions with thin rim enhancement after 90Y administration responded to treatment. The median survival times were 660 and 236 days for Okuda stage I and Okuda stage II disease, respectively.nnnCONCLUSIONnUse of combined size and necrosis criteria may lead to more accurate assessment of response to 90Y therapy than use of size criteria alone. Imaging features after 90Y treatment, including size, necrosis, peripheral enhancing nodules, and thin rim enhancement, are described.

An initial experience:Using helical CT imaging to detect obscure gastrointestinal bleeding

Obscure gastrointestinal (GI) bleeding is a common but frustrating disease for clinicians because of its elusive nature despite extensive work-up. We evaluate the role of helical computed tomography (CT) imaging using rapid infusion of intravenous contrast and water as oral contrast in the work-up of patients who are actively bleeding. Helical CT may be a useful noninvasive, alternative study to consider when routine work-up fails to determine the cause of active GI bleeding. Our preliminary study shows that helical CT was able to identify a wide variety of causes of obscure GI bleeding.

Tumor Response after Yttrium-90 Radioembolization for Hepatocellular Carcinoma: Comparison of Diffusion-weighted Functional MR Imaging with Anatomic MR Imaging

PURPOSEnAnatomic magnetic resonance (MR) imaging assessment of hepatocellular carcinoma (HCC) response to yttrium-90 ((90)Y) radioembolization may require 3 months before therapeutic effectiveness can be determined. The relationship between anatomic MR and diffusion-weighted imaging (DWI) changes after (90)Y therapy is unclear. The present study tested the hypothesis that apparent diffusion coefficient (ADC) values on DWI at 1 month precede anatomic tumor size change at 3 months after (90)Y radioembolization.nnnMATERIALS AND METHODSnIn this prospective study, 20 patients with HCC (16 men) enrolled between April 2005 and July 2006 underwent lobar (90)Y therapy with mean doses of 141 Gy (right lobe) and 98 Gy (left lobe). Anatomic 1.5-T MR imaging (gadolinium-enhanced T1-weighted gradient-recalled echo) and DWI (single-shot spin-echo echo-planar imaging; b value of 0, 500 sec/mm(2)) were performed at baseline (0-3 weeks before (90)Y therapy) and at 1 and 3 months after (90)Y therapy. Tumor size and ADC values were measured and compared, and the percentage change in ADC was compared to the change in tumor size (minimum >5% change in size), with use of a paired t test (alpha = .05).nnnRESULTSnYttrium-90 therapy was successfully delivered in all patients. The mean baseline ADC of 1.64 x 10(-3) mm(2)/sec +/- 0.30 significantly increased to 1.81 x 10(-3) mm(2)/sec +/- 0.37 at 1 month (P = .02), and to 1.82 x 10(-3) mm(2)/sec +/- 0.23 at 3 months (P = .02). The mean baseline tumor size of 83.0 cm(2) +/- 63.7 did not change statistically at 1 month (84.1 cm(2) +/- 62.1; P = .75) or 3 months (74.0 cm(2) +/- 57.0; P = .10). The overall mean ADC percentage change at 1 month of 10.5% +/- 23.1% preceded an overall mean tumor size percentage change at 3 months of -18.5% +/- 31.5% (P = .03).nnnCONCLUSIONSnHCC tumor response assessed with DWI at 1 month preceded anatomic size changes at 3 months after (90)Y therapy. DWI may assist in early determination of the response or failure of (90)Y therapy for HCC.

Multishot diffusion-weighted PROPELLER magnetic resonance imaging of the abdomen

Objective:The objective of this study was to evaluate the feasibility of using multishot PROPELLER for diffusion-weighted imaging (DWI) of the abdomen. Materials and Methods:Diffusion-weighted abdominal imaging was performed in 9 healthy volunteers and 3 patients using both single-shot DW-SE-EPI and multishot DW-PROPELLER (BLADE sequence). We compared ADC measurements in phantoms, liver and pancreatic tissues and performed qualitative comparisons of the diffusion-weighted images and ADC maps provided by these 2 techniques. Results:DW-PROPELLER significantly improved image quality (P < 0.05) with reduced geometric distortion and artifact. The ADC values of phantoms and abdominal organs measured by DW-PROPELLER were generally greater than those measured by single-shot DW-SE-EPI. The ADC values measured by both DWI techniques were significantly different for liver tissues but not for pancreatic tissues (P < 0.05). Preliminary patient studies demonstrated clearly distinguished lesion areas from surrounding normal liver tissues in the DW-PROPELLER images. DW-PROPELLER offers the potential for high-resolution DWI of the abdomen. Conclusions:The multishot DW-PROPELLER sequence is a promising technique for DWI of abdominal organs. Future clinical studies will evaluate the use of DW-PROPELLER technique for abdominal oncologic imaging applications.