Extrapulmonary tuberculosis: an old but resurgent problem.

Tuberculosis (TB) primarily affects the lungs, but some of its most devastating clinical consequences arise because of its ability to spread from the lungs to other organs. Extrapulmonary TB (EPTB) constitutes 15-20% of all TB cases. Imaging findings are not always specific and can mimic many diseases; therefore, EPTB should be considered in the differential diagnosis, particularly in patients with immune system disorders (AIDS, patients receiving chemotherapy, etc.) and those in other high-risk groups including people with diabetes. The bacterium's passage to the regional lymph nodes is essential for developing a protective T-cell-mediated immune response, but the bacterium can spread hematologically and via the lymphatic system, leading to extrapulmonary involvement. Diagnosis of EPTB in high-risk patients is made based on suspected clinical and radiological findings, but further positive culture and histopathological confirmation may be required in some instances. Radiological evaluations are critical for diagnosis and crucial in planning the treatment and follow-up. This paper aims to review the typical and atypical imaging features and the differential diagnosis of EPTB.

Primary breast tuberculosis: imaging findings of a rare disease.

Breast tuberculosis is a rare form of extrapulmonary tuberculosis which tends to affect females of reproductive age, and is much rarer in males, postmenopausal women, and pre-pubescent girls. It is difficult to diagnose because it can mimic benign conditions such as a fibroadenoma, as well as malignant diseases like a carcinoma. It is also particularly difficult to distinguish breast tuberculosis from granulomatous mastitis, so other possible diagnoses should be ruled out first. The diagnosis of breast tuberculosis has three essential pillars: clinical examination, radiological evaluations, and histopathological sampling. Radiological evaluations are not only critical in diagnosis but are also important in the planning of the treatment and during the follow-up. This paper aims to review the imaging findings and the differential diagnosis of breast tuberculosis.

Multidetector-row computed tomography enterographic assessment of the ileal-anal pouch: descriptive radiologic analysis with endoscopic and pathologic correlation.

OBJECTIVE: To describe the multidetector-row computed tomography enterographic (MD-CTE) features of the ileal-anal pouch after ileal pouch anal anastomosis (IPAA) surgery and correlate them with pouch endoscopy and histopathologic findings. METHODS: All MD-CTE examinations performed on patients who underwent IPAA from July 1, 2005 to December 1, 2010 (n = 35; 16 [45.7%] men; mean age, 37.7 years; age range, 22-72 years) were retrospectively evaluated in consensus by 2 radiologists. All studies were evaluated for the presence of multiple imaging features. Two radiographic scores were then calculated: a total radiographic score and a radiographic active inflammation score. In patients who underwent MD-CTE, pouch endoscopy, and biopsy within 30 days (n = 13), both scores were correlated with findings on pouch endoscopy and histopathology. RESULTS: Of the 35 patients, 33 (94%) had at least one MD-CTE finding of active or chronic pouch inflammation and 27 patients (77%) had at least one MD-CTE finding of active pouch inflammation. Of the 13 patients who underwent endoscopy and biopsy, the total radiographic score demonstrated a strong positive correlation with endoscopic score (r = 0.81; P = 0.001) and a moderate positive correlation with histopathologic score (r = 0.56; P = 0.047). The radiographic active inflammation score demonstrated a strong positive correlation with endoscopic score (r = 0.83; P = 0.0004), but only a weak nonsignificant positive correlation with histopathologic score (r = 0.492, P = 0.087). CONCLUSIONS: In patients who had IPAA surgery, findings on MD-CTE correlate positively with findings on pouch endoscopy and histopathology and are sensitive measures for pouch inflammation with high positive predictive value. Thus, MD-CTE can be a useful noninvasive test in the early evaluation of symptomatic patients.

Dynamic computed tomographic evaluation of vocal cord mobility in patients with larynx cancer.

OBJECTIVE: To evaluate the accuracy of dynamic laryngeal computed tomography (DLCT) for the detection of vocal cord mobility in larynx cancer. METHODS: Vocal cord mobility of 44 patients (36 men; age range, 49-81 years) with larynx cancer was examined; 13 patients were excluded (owing to poor image quality or bilateral vocal cord involvement), and vocal cord mobility was evaluated for the remaining 31 patients qualitatively and quantitatively with dynamic laryngeal computed tomography during phonation, inspiration, and Valsalva maneuver phase. RESULTS: The mobile cords were laterally positioned in a straight configuration on inspiration phase. Phonation phase images revealed medial displacement with protrusion of the cords (shoulder sign) and ventricular niche (31 patients/42 cords). Fixed cords (13 patients/13 cords) conserved their configuration and location during all phases. The distances of the vocal cords to the midline were measured based on the images obtained during inspiration and Valsalva maneuvers. The mean ± SD difference between the movement distances of cords measured during each phase was as follows: 6.16 ± 1.64 mm for the mobile cord (n = 42) and 3.17 ± 0.78 mm for the impaired cord (n = 7) on the midcoronal plane (P = 0.0001). A comparison between the mean distance values of the mobile, impaired and fixed cords groups revealed significant distance. CONCLUSIONS: Dynamic laryngeal computed tomography of the larynx of patients with laryngeal cancer can be used as a supplemental tool to examine cord mobilization for accurate T-staging (particularly for patient laryngoscopy, which is difficult to perform), and can provide additional information to physicians.

Diffusion-weighted MRI of focal cystic pancreatic lesions at 3.0-Tesla: preliminary results.

PURPOSE: To determine the utility of 3.0-Tesla diffusion-weighted (DW) magnetic resonance imaging (MRI) for focal cystic pancreatic lesion (FCPL) characterization. MATERIALS AND METHODS: 55 FCPL (34 IPMN, 5 serous cystadenoma, and 16 inflammatory) were evaluated. Two radiologists reviewed in consensus DW-MRI images. Reference standard was obtained from patient history, cytological and histopathology data, FCPL fluid analysis, and follow-up imaging results. Signal intensity (SI) and apparent diffusion coefficient values (ADC) of FCPL and normal pancreas were measured. FCPL-to-pancreas SI and ADC ratios were also calculated. RESULTS: Qualitatively, 11 of 21 non-mucinous vs. 4 of 34 mucinous lesions appeared hyperintense at b value of 1,000 s/mm(2) (P = 0.02). Three FCPL demonstrated restricted diffusion: all inflammatory. Significant differences in mean ADC between neoplastic vs. non-neoplastic (P = 0.009), and mucinous vs. non-mucinous (P = 0.013) lesions were demonstrated. FCPL-to-pancreas ADC and SI ratios demonstrated significant differences between neoplastic vs. non-neoplastic lesions [ADC, (P = 0.019); SI for b values 750 (P = 0.010) and 1,000 s/mm(2) (P = 0.017)] and mucinous vs. non-mucinous lesions [ADC (P = 0.018); SI for b values 750 (P = 0.013) and 1,000 s/mm(2) (P = 0.015)]. CONCLUSION: Although mean ADC values and FCPL-to-pancreas SI and ADC ratios may be helpful in differentiating FCPL, characterization of individual FCPL by means of 3.0-Tesla DW-MRI appears limited.

Feasibility of low-tube-voltage excretory phase images during CT urography: assessment using a dual-energy CT scanner.

OBJECTIVE: The purpose of this study is to assess the feasibility of low-tube-voltage images during excretory phase CT urography. MATERIALS AND METHODS: In this retrospective study, we examined 70 consecutive CT urograms (35 men and 35 women; mean age, 58.5 years) performed on a dual-energy CT scanner and compared excretory phase images obtained at 80 kVp and 340 mAs with blended images (0.3 × 140 kVp and 80 mAs; and 0.7 × 80 kVp and 340 mAs). Quantitative measurements of urinary system opacification (Hounsfield units), image noise (Hounsfield units), and effective dose (millisieverts) were compared using Student paired t test. Image noise was correlated with patient thickness. Two independent blinded readers qualitatively assessed opacification, image quality (both compared using Wilcoxon test), overall acceptability (compared using McNemar test), and detectability of urinary and extraurinary findings. RESULTS: The 80-kVp images yielded significantly higher opacification of renal pelvis (p < 0.0001), ureter (p < 0.0001), bladder (p < 0.0001), and aorta (p < 0.0001); higher image noise (p < 0.0001); and lower radiation dose (5.2 vs 11.9 mSv). Image noise increased along with increasing patient thickness (r = 0.86 for 80-kVp images). Qualitative opacification scores were better only in the bladder on 80-kVp images (p = 0.002). Although 80-kVp image quality was lower (p < 0.0001), the overall acceptability was similar. Of 42 urinary findings, 40 were detected on 80-kVp images (< 2-mm calyceal calculus and tiny foci of collecting system gas were missed in one patient each, both large patients). Of 137 extraurinary findings, 130 were detected on 80-kVp images (no findings of high clinical significance were missed). CONCLUSION: Low tube voltage (80 kVp) during excretory phase CT urography is feasible, with improved urinary system opacification, acceptable image quality, and lower radiation dose.

Dynamic MR defecography: assessment of the usefulness of the defecation phase.

OBJECTIVE: The purpose of this study was to assess the usefulness of the defecation phase during dynamic MR defecography. MATERIALS AND METHODS: The images from 85 MR defecographic examinations (83 patients; age range, 20-88 years; mean, 52.7) were retrospectively reviewed in consensus by two observers. Images from each of four phases (rest, maximal sphincter contraction and squeezing, maximal straining, and defecation) were evaluated and scored independently with a modified previously published grading system. Features evaluated included the presence and degree of bladder, vaginal, and rectal descent and the presence and size of rectocele, enterocele, and intussusception. Statistical analysis was performed with a variety of tests. RESULTS: Compared with images obtained in the other phases, defecation phase images helped in identification of additional cases of abnormal bladder descent in 43 examinations (50.6%), abnormal vaginal descent in 52 examinations (61.2%), and abnormal rectal descent in 11 examinations (12.9%). Similarly, only defecation phase images depicted previously undetected rectoceles 2 cm or larger in 31 examinations (36.5%), enteroceles in 34 examinations (40%), and intussusceptions in 22 examinations (25.9%). The number of additional cases of abnormalities identified on defecation phase images was significantly greater than the number identified on images obtained in the other phases (p < 0.005). The average total scores for the rest, squeeze, strain, and defecation phases were 1.4, 0.7, 2.3, and 6.6. The average total defecation phase score was significantly greater than the average total score in any of the other phases (p < 0.001). CONCLUSION: During dynamic MR defecography, defecation phase imaging yields important additional information on the presence and degree of pelvic floor abnormalities and is therefore an essential component of MR defecographic examinations.

Autoimmune hepatitis: CT and MR imaging features with histopathological correlation.

BACKGROUND: To describe the CT and MRI features of autoimmune hepatitis (AIH) and correlate them with histological grade and stage. Observed changes associated with treatment are also described. METHODS: A retrospective analysis of the initial CT scans (n = 22) and MRI exams (n = 12) of 27 patients with pathologically-proven AIH was conducted. Multiple objective and subjective imaging features were evaluated. Correlation of imaging features with histological inflammatory grade and fibrotic stage was performed using the Fisher exact test and Spearman's rank correlation coefficient. In eight patients serial CT and MR imaging during treatment was used to describe the changes associated with treatment. RESULTS: The presence of ascites, expanded gallbladder fossa, spleen size, and enlarged preportal space had significant positive correlations with fibrotic stage. No significant positive correlations existed between imaging features and portal or lobular inflammatory grade. Seven patients (25.9%) were normal. The most common abnormal finding was surface nodularity: CT (n = 11 [50%]) and MRI (n = 8 [66.7%]). There was a wide variability in imaging appearances of patients who had serial scans on treatment. CONCLUSIONS: There is a wide spectrum of CT and MR imaging features in patients with AIH. Several MRI features demonstrate a significant positive correlation with fibrotic stage.

Evaluation of low-density neutral oral contrast material in PET/CT for tumor imaging: results of a randomized clinical trial.

OBJECTIVE: The objective of this study was to determine the impact on image quality and risks in terms of artifacts and side effects of a low-density barium-based suspension as oral contrast material for CT during PET/CT examinations of an oncologic patient population. SUBJECTS AND METHODS: Eighty-five patients (51 men and 34 women; mean age, 53 years; age range, 21-87 years) were prospectively randomized to receive either 0.1% barium sulfate oral suspension or no oral contrast material during PET/CT. Patients in the oral contrast group were given 1,350 mL over 60-75 minutes. The (18)F-FDG PET component of each examination was reviewed for the presence of artifacts by two nuclear medicine physicians and was classified as adequate (no presence of artifactual focal FDG uptake attributed to attenuation-correction errors) or inadequate (focal uptake in attenuation-correction PET images with no corresponding uptake in non-attenuation-corrected PET images). Two radiologists reviewed the CT studies and scored the degree of bowel opacification using a 5-point scale, ranging from 0 for no opacification (i.e., not possible to delineate the bowel structures from the surrounding tissues) to 4 for excellent opacification (i.e., bowel structure identifiable and bowel wall clearly visible). The attenuation values (in Hounsfield units) were recorded in the stomach, duodenum, mid jejunum, and terminal ileum for quantitative analysis. Interobserver variability was assessed using kappa coefficients. RESULTS: None of the patients who received oral contrast material experienced side effects. All 85 PET examinations were considered adequate with no observable artifacts. The mean bowel opacification scores of the oral contrast group (2.59 and 2.93) as evaluated by radiologists 1 and 2, respectively, were significantly higher (p < 0.01) than those of the control group (1.55 and 1.59). The level of attenuation achieved in the contrast group was significantly higher than in the control group. The interobserver variability was moderate (kappa = 0.32). CONCLUSION: The use of low-density neutral oral contrast material for CT during combined FDG PET/CT studies significantly improves visualization of the bowel structures compared with no contrast material without causing side effects or clinically detectable errors in the attenuation correction of the FDG PET study.

CT-guided percutaneous catheter drainage of acute necrotizing pancreatitis: clinical experience and observations in patients with sterile and infected necrosis.

OBJECTIVE: The purpose of this study was to report on clinical experience with and observations made during primary CT-guided percutaneous catheter drainage of acute necrotizing pancreatitis and to compare results among patients with sterile and those with infected necrosis. MATERIALS AND METHODS: We reviewed clinical, radiologic, and bacteriologic data on 35 patients (23 men, 12 women; mean age, 50 years; range, 21-83 years) with acute necrotizing pancreatitis refractory to standard medical care who underwent CT-guided percutaneous catheter drainage with 12- to 22-French catheters. Experiences with two subgroups were compared. One group consisted of 22 patients, 10 with multisystem organ failure, who presented with sterile necrosis (median Atlanta score, 1.3; range, 0-3). The other group consisted of 13 patients, one with multisystem organ failure, who presented with infected necrosis (median Atlanta score, 0.4; range, 0-3). Differences between the group with sterile and the group with infected necrosis were analyzed with the Fisher-Holton exact and Mann-Whitney U tests. RESULTS: Among 35 patients, 17 (49%) were treated successfully with CT-guided percutaneous catheter drainage alone. The effectiveness of CT-guided percutaneous catheter drainage in patients with sterile necrosis (11/22, 50%) was not significantly different from that of drainage in patients with infected necrosis (6/13, 46%). Among 11 patients with multisystem organ failure (10 with sterile necrosis, one with infected necrosis), only four (36%) were treated successfully with CT-guided percutaneous catheter drainage alone; five patients (45%) died. Among 24 patients without multisystem organ failure, 13 (54%) were treated successfully with CT-guided percutaneous catheter drainage alone; one patient died. CONCLUSION: In our experience, primary CT-guided percutaneous catheter drainage was successful for approximately one half of the patients with acute necrotizing pancreatitis. The presence of multisystem organ failure appears to be a more important indicator of outcome than does the presence of infection.

Predictive value of percutaneous imaging-guided biopsy of peritoneal and omental masses: results in 111 patients.

OBJECTIVE: The objective of our study was to determine the predictive value of percutaneous imaging-guided biopsy of peritoneal and omental masses. MATERIALS AND METHODS: A retrospective study of 111 patients who underwent biopsy of a peritoneal or omental mass from 1998 to 2006 was performed. Biopsy results were classified as diagnostic (malignant or benign) or nondiagnostic. Sensitivity, specificity, and negative predictive value (NPV) were calculated for all patients, and the Fisher-Freeman-Halton exact test was used to determine whether test characteristics varied by patient history (presence of a known cancer), mass size (<4 cm vs >or= 4 cm), and needle size (biopsies with fine needles vs biopsies with fine and large needles). RESULTS: The overall diagnostic rate was 89% (99/111); there were 86 true-positive, one false-positive, six true-negative, and six false-negative results (sensitivity, 93% [86/92]; specificity, 86% [6/7]; NPV, 50% [6/12]). There were no statistically significant differences between patients with and without known cancer. Among 79 patients with known cancer, 52 (66%) had metastatic disease from the known cancer; in eight (10%) patients, the biopsy result yielded new primary cancers. Of 32 patients with no known cancer, 23 (72%) had malignant results. Biopsy test characteristics did not differ with respect to mass or needle size. Minor complications were seen in three (3%) patients. CONCLUSION: Percutaneous imaging-guided biopsy of peritoneal and omental masses is a safe, effective procedure that is useful in clinical practice. A second malignancy was revealed in a substantial number of patients with a known primary cancer. A new malignancy was diagnosed in most patients without a history of cancer.

Pancreatic intraductal papillary mucinous neoplasms: role of CT in predicting pathologic subtypes.

OBJECTIVE: The objective of our study was to evaluate whether CT can be used to predict the pathologic subtypes of pancreatic intraductal papillary mucinous neoplasms (IPMNs). MATERIALS AND METHODS: Three radiologists, blinded to the pathologic IPMN subtype, retrospectively and independently reviewed the preoperative CT scans of 38 patients with surgically resected pancreatic IPMN: 11 intraductal papillary mucinous adenomas, 11 intraductal papillary mucinous carcinomas, and 16 intraductal papillary mucinous carcinomas with invasion. The patients, 16 women and 22 men, ranged in age from 38 to 80 years (mean age, 64.3 years). CT findings were correlated with each pathologic subtype using the chi-square (two-sided) test and analysis of variance. Interobserver agreement of the CT diagnosis of pathologic subtype and agreement between the CT diagnosis and pathologic subtype were also studied (kappa statistic). RESULTS: Predominant main pancreatic duct (MPD) involvement (p = 0.04) and a wide (> 1 cm) connection of a side-branch lesion with the MPD (p = 0.03) correlated with intraductal papillary mucinous carcinoma with invasion. Tumor size, MPD diameter, number of tumors per patient, number of pseudoseptations per tumor, common bile duct dilatation, enlarged lymph nodes, intraductal calcifications, papillary bulging, and presence and size of a solid mass yielded no statistically significant relationship with pathologic subtype. Both interobserver agreement of CT diagnosis (range, 0.004-0.359) and agreement between CT diagnosis and pathologic subtype (range, 0.046-0.317) ranged from slight to fair. CONCLUSION: Prediction of the pathologic subtypes of pancreatic IPMNs by CT is limited. Predominant MPD involvement and a wide connection of a side-branch lesion with the MPD are the only CT findings that can be used to predict the pathologic subtype of pancreatic IPMN.

Comparison of neutral oral contrast versus positive oral contrast medium in abdominal multidetector CT.

To determine whether neutral contrast agents with water-equivalent intraluminal attenuation can improve delineation of the bowel wall and increase overall image quality for a non-selected patient population, a neutral oral contrast agent (3% mannitol) was administered to 100 patients referred for abdominal multidetector row computed tomography (MDCT). Their results were compared with those of 100 patients given a positive oral contrast agent. Qualitative and quantitative measurements were done on different levels of the gastrointestinal tract by three experienced readers. Patients given the neutral oral contrast agent showed significant better qualitative results for bowel distension (P < 0.001), homogeneity of the luminal content (P < 0.001), delineation of the bowel-wall to the lumen (P < 0.001) and to the mesentery (P < 0.001) and artifacts (P < 0.001), leading to a significant better overall image quality (P < 0.001) than patients receiving positive oral contrast medium. The quantitative measurements revealed significant better distension (P < 0.001) and wall to lumen delineation (P < 0.001) for the patients receiving neutral oral contrast medium. The present results show that the neutral oral contrast agent (mannitol) produced better distension, better homogeneity and better delineation of the bowel wall leading to a higher overall image quality than the positive oral contrast medium in a non-selected patient population.

Intestinal obstruction: trends in imaging utilization and their influence in its rising hospital bill.

The purpose of the study was to evaluate trends in the utilization of different imaging modalities and review how imaging utilization practices affect hospital charges for patients with intestinal obstruction. All patients discharged with a primary diagnosis of intestinal obstruction during 6 fiscal years (1999-2004) were retrospectively studied. We obtained data on patients' demographics, procedures, outcomes, imaging services utilization, and hospital and imaging charges from our institution's transition system (a clinical and financial decision support software system). The institutional review board approved this study. Surgery was performed in 26% of patients in 1999 and in 40% in 2004 (p = 0.01) with the mortality rate significantly (p < 0.01) dropping from 3.8% to 0.4%. A total of 5,292 abdominal imaging studies were obtained; 93% of those were either abdominal radiographs or abdomino-pelvic computed tomography (CT) scans. CT studies per patient increased from 0.5 in 1999 to 1 in 2004 (p < 0.01), while abdominal radiographs (mean = 2.4) did not significantly change over the entire study period (p = 0.6). Average imaging charges doubled during the study period ($1,572 to $3,012, p < 0.01). Average hospital charges increased from $18,138 in 1999 to $32,808 in 2004 (p < 0.01). The fraction of hospital charges attributed to imaging varied between 8.7% and 9.2%. CT utilization for intestinal obstruction increased from 1999 to 2004 without modality substitution. While hospital and imaging charges have significantly increased, the fraction represented by imaging has remained constant, suggesting that imaging is an unlikely cause for the increase in hospital charges.

Survey of the use of quality indicators in academic radiology departments.

OBJECTIVE: Our purpose was to determine whether quality in academic radiology departments in the United States is systematically measured through indicators and evaluated by preset standards. MATERIALS AND METHODS: We performed a cross-sectional study using a validated survey sent to Society of Chairmen of Academic Radiology Departments (SCARD) members and studied type, frequency of monitoring, and use of preset standards for evaluation of quality indicators. Statistical methods were descriptive summary statistics, chi-square test, analysis of variance, and Spearman's rank correlation test. RESULTS: The response rate was 42% (55/132). Most responding hospitals were from the Northeast (20/55, 36.4%) and Midwest (18/55, 32.7%). About 58% (32/55) of the responding hospitals had more than 500 beds in operation; 50.9% (28/55) of the radiology departments performed 200,000-400,000 examinations per year. Among the 80% of departments (44/55) that monitored patient satisfaction, only 49.1% and 45.5% assessed referring physician and employee satisfaction, respectively. The most frequently monitored customer satisfaction indicator, patient satisfaction, was monitored quarterly or less frequently by 70.5% (31/44) of departments; about 45.5% (20/44) had preset standards for this indicator. MRI and CT were monitored for patient appointment access by 80% (44/55) and 72.7% (40/55) of departments, respectively; 59.1% (26/44) and 62.5% (25/40) of departments applied preset standards to these indicators, respectively. The reporting-time indicator monitored most frequently was report turnaround time (45/55, 81.8%). None of the differences in mean numbers and monitoring frequencies of the indicators and the use of preset standards to evaluate them by region and size of departments were significant (p >0.05). CONCLUSION: Use of quality management indicators, particularly customer satisfaction indicators, is not a fully standardized and established process for academic radiology departments in the United States.

Key criteria for selection of radiology residents: results of a national survey.

RATIONALE AND OBJECTIVES: We sought to identify the criteria that academic radiology departments in the United States consider for selecting their residents. MATERIALS AND METHODS: In a cross-sectional study, a validated survey was sent to all the program directors of radiology residency programs. A total of 25 variables were studied. Descriptive statistics and correlations were calculated by the chi2 test. Nonparametric correlations were calculated with the Kruskal-Wallis rank test. Statistical significance was set at 5% alpha-error level (P<.05). RESULTS: We had a response rate of 53.1% (77 of 145). All responders participate in the National Resident Matching Program (NRMP), and 93.5% fill all their positions through NRMP. The preinterview selection criteria showed no significant difference by size, region, or affiliation with a medical school. An "interviewing body" carries out the interview process in 87.3% of the cases. Residents and fellows are part of the interviewing body in 76.5% of the programs, the body has the final word in accepting candidates in 62.9% of the programs, 55.4% of the programs use score sheets during interviews with candidates, and only 6.5% of the programs perform panel interviews. Programs associated with a medical school are significantly more likely to have more members in their interviewing body and to use score sheets when evaluating candidates, and panel interviews (more than one candidate or interviewer) are significantly more common among programs in the northeast region. CONCLUSION: All preinterview selection criteria and some interview structural characteristics are independent of the program's size, region, or affiliation with a medical school. More research regarding optimal preselection and interview processes is needed, and closer attention should be paid to the NRMP process if current practices are to be maintained.

Diffusion-weighted MR imaging in the evaluation of pancreatic exocrine function before and after secretin stimulation.

OBJECTIVES: To evaluate diffusion weighted MR imaging before and after secretin stimulation in the assessment of pancreatic exocrine function in the setting of chronic pancreatitis. METHODS: Nine patients with severe chronic pancreatitis and sixteen patients without chronic pancreatitis but with a history of chronic alcohol consumption were enrolled in the chronic pancreatitis and risk groups, respectively. Thirty-eight patients without any pancreatic disease or history of alcohol consumption were included in the control group. Diffusion weighted images were obtained before and after secretin administration in all patients. The peak ADC values and times were determined and intergroup differences were compared. A receiver operating characteristic curve (ROC) was used to identify the cutoff values of the peak ADC times for discrimination of control group from risk and chronic pancreatitis groups. RESULTS: In the control group, a peak increase in ADC value of 57-120% (median: 75%) was observed between 90 s and 4 min (median: 2 min) after administration of secretin (Pattern 1). In the risk group, in 13 patients, a peak increase of 52-150% was observed between 4 and 8 min (median: 7 min; Pattern 2). Peak times were significantly longer in risk group (p < 0.01). In three patients in the risk group, and in all patients in the chronic pancreatitis group, no ADC peak was observed within 10 min following secretin administration (Pattern 3). Using a peak time of 4 min as the cut-off value, a sensitivity of 100% and specificity of 94.7% were achieved in discriminating the control group from the combined risk and chronic pancreatitis groups. CONCLUSION: Diffusion-weighted MR imaging before and after secretin administration could yield clinically useful information for detecting pathophysiologic alterations in the setting of chronic pancreatitis.