Magnetic resonance imaging in determination of myocardial ischemia and viability: comparison with positron emission tomography and single-photon emission computed tomography in a porcine model

Background: In patients with chronic left ventricular dysfunction, the size of the viable cardiac muscle is correlated with the prognosis and the outcome of myocardial revascularization.

Purpose: To evaluate the diagnostic value of various imaging techniques in determination of myocardial ischemia and viability.

Material and Methods: A chronic myocardial ischemia animal model was established, in which 10 pigs underwent magnetic resonance imaging (MRI), positron emission tomography (PET), and single-photon emission computed tomography (²⁰¹Tl SPECT) before and 1-2 months after modeling. The size of myocardial ischemia and necrosis was judged, and the imaging manifestations were compared with pathologic findings.

Results: Seven of the 10 animals completed all examinations uneventfully. On dobutamine-stressed cine MRI, 10 (8.93%) segments were found to be akinetic. Perfusion was abnormal in 34 (30.35%) segments. Delayed hyperenhancement was observed in 12 (10.71%) segments. PET detected myocardial necrosis in 17 (15.18%) segments, and SPECT detected myocardial necrosis in nine (8.04%) segments. Histological examination with triphenyltetrazolium chloride (TTC) showed pale necrosis in 14 (12.50%) segments. The number of necrotic segments detected by PET was significantly greater than that by contrast-enhanced MRI (χ² = 5, P = 0.0253, kappa = 0.8028) and cine MRI (χ² = 7, P = 0.0082, kappa = 0.7079). It was also greater than that by TTC (χ² = 3, P = 0.0833, kappa = 0.8879), although the difference was statistically insignificant. The number of necrotic segments detected by SPECT was significantly smaller than that by TTC (χ² = 5, P = 0.0253, kappa = 0.7590), as was the number of necrotic segments detected by cine MRI (χ² = 4, P = 0.0455, kappa = 0.8100). There was no statistically significant difference in the detection of necrotic segments between contrast-enhanced MRI and TTC (χ² = 2, P = 0.1573, kappa = 0.9130).

Conclusion: Cardiac MRI can determine viable myocardium and clearly delineate the location and degree of myocardial necrosis. PET slightly overestimates the extent of the necrotic myocardium and is unable to distinguish transmural necrosis from subendocardial necrosis.     

Tumor extension in high-grade gliomas assessed with diffusion magnetic resonance imaging: values and lesion-to-brain ratios of apparent diffusion coefficient and fractional anisotropy

Purpose: To determine whether the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) can distinguish tumor-infiltrated edema in gliomas from pure edema in meningiomas and metastases.

Material and Methods: Thirty patients were studied: 18 WHO grade III or IV gliomas, 7 meningiomas, and 5 metastatic lesions. ADC and FA were determined from ROIs placed in peritumoral areas with T2-signal changes, adjacent normal appearing white matter (NAWM), and corresponding areas in the contralateral healthy brain. Values and lesion-to-brain ratios from gliomas were compared to those from meningiomas and metastases.

Results: Values and lesion-to-brain ratios of ADC and FA in peritumoral areas with T2-signal changes did not differ between gliomas, meningiomas, and metastases (P = 0.40, P = 0.40, P = 0.61, P = 0.34). Values of ADC and FA and the lesion-to-brain ratio of FA in the adjacent NAWM did not differ between tumor types (P = 0.74, P = 0.25, and P = 0.31). The lesion-to-brain ratio of ADC in the adjacent NAWM was higher in gliomas than in meningiomas and metastases (P = 0.004), but overlapped between tumor types.

Conclusion: Values and lesion-to-brain ratios of ADC and FA in areas with T2-signal changes surrounding intracranial tumors and adjacent NAWM were not helpful for distinguishing pure edema from tumor-infiltrated edema when data from gliomas, meningiomas, and metastases were compared.     

Characteristics of timed barium esophagogram in newly diagnosed idiopathic achalasia: clinical and manometric correlates

Purpose: To describe timed barium esophagogram (TBE) characteristics in patients with newly diagnosed idiopathic achalasia, and to correlate these with clinical and manometric variables.

Material and Methods: Forty-six consecutive patients with newly diagnosed achalasia were examined with TBE. Esophageal emptying was assessed using the height, area, and volume of the barium column. Subjective evaluation was performed according to a standardized protocol in all patients. Objective diagnostic evaluation included manometry.

Results: At the 1-min time point after contrast ingestion, the static parameters median height, maximum, and mean width of the barium column were 16.0, 4.4, and 3.3 cm, respectively. Emptying, expressed as volume of barium, showed significant inverse correlation with the resting and the maximal relaxing pressure of the lower esophageal sphincter (LES) (R = -0.34 and R = -0.54, respectively). There was also an inverse correlation between emptied volume at TBE and the duration of symptoms (R = -0.36), and between barium column width and postprandial chest pain (R = -0.44).

Conclusion: All patients with newly diagnosed achalasia presented with delayed emptying of barium the esophagus at TBE. The estimated emptied volume of barium (related to the ingested volume) correlated inversely with the basal tone and the relaxation pressure of the LES. Including estimation of the volume of emptied barium at TBE resulted in closer correlation with manometric values of LES tone than using the parameters traditionally recorded.     

Is a flared stent effective for decreasing stent migration in canine prostatic urethra?

Background: Prostatic urethral stents are effective in relieving obstructions caused by benign prostatic hyperplasia (BPH). However, migration of these stents occurs frequently.

Purpose: To evaluate the efficacy of a flared stent for decreasing the migration rate in comparison with a straight stent in a canine prostatic urethral model.

Material and Methods: The flared stent (15 mm in diameter and 20 mm in length) was flared up to 19 mm at both ends to prevent migration. A straight stent with the same size was straight without flaring. Both stents were made of a nitinol wire filament and covered with an expanded polytetrafluoroethylene (ePTFE) membrane. The flared stent was inserted in the prostatic urethra of 10 dogs (group 1) and the straight stent in the prostatic urethra of 12 dogs (group 2). Follow-up retrograde urethrography (RUG) was performed 1, 4, and 8 weeks after stent placement. Fisher's exact test was used to compare the migration rate between the two groups. When stent migration occurred during the follow-up period, the same type of stent was inserted again.

Results: Three of 10 (30.0%) flared stents migrated into the urinary bladder between 1 week and 4 weeks after placement. Seven of 12 (58.3%) straight stents migrated into the urinary bladder 1 (n = 3), 4 (n = 1), and 8 (n = 3) weeks following placement. The flared stent group showed lower migration rate than the straight stent group, but the migration rate did not reach statistical significance (P = 0.231). After the second stent placement, one of three (33.3%) flared stents migrated again after 4 weeks and two of seven straight stents (28.6%) after 1 week.

Conclusion: Although the migration rate was not statistically significant, the flaring of the stent seemed to reduce the migration rate in comparison with straight stents in a canine prostatic urethral model. However, the migration rate of the flared stent was still high, and further developments are required to decrease migration rate.     

Is subcutaneous local anesthesia in shoulder magnetic resonance arthrography necessary?

Background: Magnetic resonance arthrography is a well-established diagnostic method in degenerative and traumatic disorders of the shoulder. Some radiologists prefer to apply a local anesthetic to the skin prior to performing the joint puncture. However, no information regarding the efficacy of local anesthetics exists.

Purpose: To assess patient discomfort in arthrography injection.

Material and Methods: A patient survey (n = 74) utilizing a visual analog scale (VAS) measured the intensity of pain in arthrography injection by those receiving local anesthetics (n = 36) versus those who did not (n = 38).

Results: Mean VAS scores were 20.8 (median 10.5, SD 24.3) for those receiving local anesthetics versus 19.3 (median 13.0, SD 20.7) for those who did not (P = 0.83, Mann-Whitney U test).

Conclusion: Routine use of local anesthesia of the skin in arthrography injection is unnecessary.     

Do contrast media (iomeprol, gadopentetate dimeglumine) deteriorate ischemia/reperfusion injury of the liver?

Background: Hepatic microcirculation is a main determinant of reperfusion injury and graft quality in liver transplantation. One of the important diagnostic procedures to recognize reperfusion failure is contrast-enhanced computed tomography or magnetic resonance imaging.

Purpose: To examine the additional effect of contrast media (iomeprol and gadopentetate dimeglumine) on hepatic microcirculation and hepatic cellular damage in the phase of early ischemia/reperfusion injury of the rat liver.

Material and Methods: The partial warm ischemia-reperfusion injury model of rat liver was used. Microcirculation and leukocyte-endothelium interaction were measured by intravital microscopy. Hepatic cellular damage was indicated by liver enzyme activity in the sera. The evaluation parameters were measured at baseline and at 30, 60, and 90 min after reperfusion. The contrast media (iomeprol group, n = 6; gadopentetate dimeglumine group, n = 6) or Ringer's solution (control group, n = 8) were applied after 30 min of reperfusion.

Results: No additional injury to the ischemia/reperfusion injury of the liver after intravenous application of radiographic contrast media was found. Some protective effect was even recorded after application of iodinated contrast media.

Conclusion: The use of contrast media during diagnostic procedure of the liver seems to be relatively safe, even in the stage of early reperfusion after liver transplantation.     

Computed tomography of the urinary tract: optimalization of low-dose stone protocol in a clinical setting

Purpose: To establish whether information would be lost if slice reconstruction thickness was increased from 3 to 5 mm, and whether this altered how difficult it was to interpret the examinations.

Material and Methods: Twenty-three consecutive patients referred with suspected or known urinary stones were included. All examinations were performed without intravenous contrast media. The original series, with effective mAs 50, were reconstructed with slice thickness 3 and 5 mm, respectively. All demographic and examination data were removed and the series reviewed in PACS by two independent radiologists. Objective findings, i.e. number and size of stones, signs of obstruction, and evaluation of interpretation difficulty, were registered.

Results: Identical findings were registered in 18 of the series of 3 mm (n = 23) and 19 of the series of 5 mm (n = 23). In two series reconstructed with 3 mm slice thickness and in one series with 5 mm slice thickness, the observers disagreed on the presence of urinary stones. Main reasons for interpretation difficulties were given as “lack of intra-abdominal fat” and “many phleboliths in the pelvic region”, but never “disturbing noise”.

Conclusion: To determine the presence and size of urinary stones at low-dose computed tomography, 5 mm reconstruction algorithm seems equal to 3 mm. Patient-related factors influence the interpretation more than image quality.     

Accessory renal artery stenosis and hypertension: are these correlated? Evaluation using multidetector-row computed tomographic angiography

Background: Renal artery stenosis may produce hypertension, and this condition is referred to as renovascular hypertension (RVH).

Purpose: To evaluate, by using multidetector-row spiral computed tomographic angiography (MDCTA), whether a relationship between accessory renal artery stenosis and hypertension may be hypothesized.

Material and Methods: 214 patients (142 males, 72 females; mean age 66 years) who had previously undergone an MDCTA to study the abdominal vasculature were retrospectively studied. Patients with renal artery stenosis (RAS) were excluded from this analysis. The patients were studied by means of a four-detector-row CT, and scans were obtained after intravenous bolus administration of 110-140 ml of a nonionic contrast material with a 3-6 ml/s flow rate. As a second step, by means of statistical analysis, hypertension data were compared with findings of accessory artery stenosis. Two radiologists first independently reviewed the MDCTA images and then, in case of disagreement, in consensus. Interobserver agreement was calculated for all measurements.

Results: The overall number of detected accessory renal arteries was 74 in 56 of the 214 patients. Accessory renal artery stenosis was detected in 21 of the 56 patients. There was a difference in the prevalence of hypertension between patients with (n = 21) and without (n = 35) accessory renal artery stenosis (P = 0.0187). Interobserver agreement was good (kappa value 0.733).

Conclusion: Any statistical association between the presence of accessory renal artery stenosis and hypertension could not be disclosed. However, accessory renal artery stenosis, detected by MDCTA, is an important pathological sign that the radiologist has to assess in the light of its possible association with hypertension.     

Attempts to improve absolute quantification of cerebral blood flow in dynamic susceptibility contrast magnetic resonance imaging: a simplified T1-weighted steady-state cerebral blood volume approach

Background: Attempts to retrieve absolute values of cerebral blood flow (CBF) by dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) have typically resulted in overestimations.

Purpose: To improve DSC-MRI CBF estimates by calibrating the DSC-MRI-based cerebral blood volume (CBV) with a corresponding T1-weighted (T1W) steady-state (ss) CBV estimate.

Material and Methods: 17 volunteers were investigated by DSC-MRI and ¹³³Xe SPECT. Steady-state CBV calculation, assuming no water exchange, was accomplished using signal values from blood and tissue, before and after contrast agent, obtained by T1W spin-echo imaging. Using steady-state and DSC-MRI CBV estimates, a calibration factor K = CBV(ss)/CBV(DSC) was obtained for each individual. Average whole-brain CBF(DSC) was calculated, and the corrected MRI-based CBF estimate was given by CBF(ss) = K×CBF(DSC).

Results: Average whole-brain SPECT CBF was 40.1±6.9 ml/min·100 g, while the corresponding uncorrected DSC-MRI-based value was 69.2±13.8 ml/min·100 g. After correction with the calibration factor, a CBF(ss) of 42.7±14.0 ml/min·100 g was obtained. The linear fit to CBF(ss)-versus-CBF(SPECT) data was close to proportionality (R = 0.52).

Conclusion: Calibration by steady-state CBV reduced the population average CBF to a reasonable level, and a modest linear correlation with the reference ¹³³Xe SPECT technique was observed. Possible explanations for the limited accuracy are, for example, large-vessel partial-volume effects, low post-contrast signal enhancement in T1W images, and water-exchange effects.     

Effect of computer-aided detection on mammographic performance: experimental study on readers with different levels of experience

Purpose: To evaluate the effect of computer-aided detection (CAD) on the reader's performance.

Material and Methods: Four screening radiologists, two novice radiologists, and two residents with no prior experience in CAD read films of 200 women without and with CAD. The films, including 16 screen-detected cancers and 35 cancers “missed” on prior screening, were divided into two rollers: A (free time schedule) and B (prompted time schedule). Reading times were noted. Individual readings without and with CAD were compared, sensitivities and specificities were calculated.

Results: The sensitivity of CAD was 70.6% and specificity 15.8%. In 408 cancer readings, the screeners found 10 and other readers 7 new cancers with the aid of CAD. The screeners changed their opinion four times and others six times from true positive to false negative when CAD was negative. CAD output produced 12 versus 13 new false-positive findings respectively after 2352 readings. CAD did not significantly affect the reader's sensitivities/specificities regardless of the time limit (P = not significant). The use of CAD increased mean time for roller reading from 56 to 63 min (P = 0.053).

Conclusion: Screening radiologists benefited slightly more from CAD than other readers did, but no statistical significant difference was found in personal readings without and with CAD.     

Noninvasive multidetector computed tomography enterography in patients with small-bowel Crohn's disease: is a 40-second delay better than 70 seconds?

Background: Multidetector computed tomography (MDCT) enterography combines neutral enteric contrast with intravenously administered contrast material. The optimal intravenous (IV) contrast material protocol has still not been established.

Purpose: To determine the optimal delay time to image patients with small-bowel Crohn's disease during MDCT enterography.

Material and Methods: After oral administration of 1350 ml of neutral contrast medium, 26 patients with small-bowel Crohn's disease underwent MDCT enterography; scans were obtained 40 s (enteric phase) and 70 s (parenchymal phase) after IV administration of 100 ml of iodinated contrast material. Three radiologists, blinded to clinical and pathological findings, independently and retrospectively evaluated each scan in two separate reading sessions for the presence or absence of CT features of Crohn's disease activity. The interobserver agreement was evaluated, and the efficacy of each phase in detecting active disease in the terminal ileum for each reader was determined. The gold standard was pathology (n = 13), endoscopy (n = 3), and clinical evaluation (n = 10).

Results: No statistically significant difference was present between the enteric and the parenchymal phase for each reader in each segment regarding the presence or absence of CT features of Crohn's disease. The interobserver agreement for the presence of five main features of active Crohn's disease in the terminal ileum ranged from poor to excellent. The sensitivity, specificity, negative predictive value, positive predictive value, and accuracy for active Crohn's disease in the terminal ileum ranged from 40 to 90%, 88 to 100%, 70 to 94%, 44 to 100%, and 69 to 96%, respectively. There was no statistical difference between the two phases for each reader.

Conclusion: MDCT enterography in patients with suspected active Crohn's disease can be obtained at either 40 s or 70 s after IV contrast material.     

Transcatheter arterial embolization for massive hemoptysis in patients with coal workers' pneumoconiosis: an 11-year experience

Background: Transcatheter arterial embolization (TAE) is a safe and well-established treatment option to control hemoptysis, but there are few studies focused on treating hemoptysis accompanying coal workers' pneumoconiosis (CWP).

Purpose: To evaluate the immediate and long-term efficacy of TAE for control of massive hemoptysis in patients with CWP, and to clarify the factors which influence the frequency of rebleeding.

Material and Methods: This study included 34 CWP patients with massive hemoptysis who were treated with 47 TAE sessions over the last 11 years. Immediate (within 1 month) and long-term outcomes (mean 37 months, range 1 month-11 years) were evaluated retrospectively. The relationships between the frequency of rebleeding and the type of CWP, angiographic findings, and presence of tuberculosis were evaluated.

Results: The immediate success rate was 91.2% (31/34). In 23 patients (68%), hemoptysis did not recur on long-term follow-up. In eight patients who received repeated procedures for recurrent hemoptysis, bleeding was discovered in the non-bronchial systemic artery (n = 13) or bronchial artery (n = 7). The frequency of recurrent hemoptysis was higher in cases with complicated pneumoconiosis (n = 7) than in cases of the simple type (n = 1; P = 0.029). There was no statistical difference between rebleeding and angiographic findings or the presence of tuberculosis.

Conclusion: TAE is an effective treatment modality for controlling massive hemoptysis in patients with CWP. However, many non-bronchial systemic collaterals contribute to recurrent hemoptysis. Furthermore, there is a high probability of rebleeding in patients with the complicated type of CWP, and extra care must be taken in the embolization procedure.     

Acceleration of primary liver tumor growth rate in embolized hepatic lobe after portal vein embolization

Background: Portal vein embolization (PVE) is now widely accepted as a useful preoperative procedure in selected patients undergoing extended hepatectomy. However, the effect of PVE on the growth of liver tumors has not been fully elucidated.

Purpose: To retrospectively evaluate the effects of PVE on the growth of liver tumors in the embolized lobes.

Material and Methods: Eight patients with a primary liver tumor, six hepatocellular carcinomas (HCC) and two cholangiocellular carcinomas (CCC), were studied. The growth rates of the tumors in the embolized lobes and non-embolized liver parenchyma were calculated using the computed tomography (CT) volume values at the time of tumor identification, and before and after PVE.

Result: The median tumor growth rate was 0.59 cm³/day (range 0.22-6.01 cm³/day) before PVE and 2.37 cm³/day (range 0.29-13.97 cm³/day) after PVE (P = 0.018). The tumor growth acceleration ratios ranged from 1.50 to 7.46 (median 2.65) in the six HCCs, and were 1.00 and 1.32 in the two CCCs. There was no apparent correlation between the tumor growth rate after PVE and the growth rate of non-embolized liver parenchyma (median 6.00 cm³/day, range 1.24-11.0 cm³/day).

Conclusion: Liver tumor growth in an embolized lobe accelerates after PVE, in patients with HCC.     

Comparison study of intraarticular and intravenous gadolinium-enhanced magnetic resonance imaging of cartilage in a canine model

Background: Magnetic resonance (MR) imaging and measurement of glycosaminoglycan (GAG) have potential for characterization of hyaline articular cartilage. Recently, some reports have demonstrated the potential of direct administration of contrast media for MR imaging of cartilage.

Purpose: To prove the feasibility of intraarticular gadolinium-enhanced MR imaging of cartilage (iGEMRIC) and T1 relaxation mapping of the articular cartilage in vivo with intraarticular injection of Gd-DTPA^2-.

Material and Methods: Five healthy beagle dogs underwent MR imaging and T1 relaxation mapping of the knee joints of both hind legs. The delayed gadolinium-enhanced MR imaging of cartilage (dGEMRIC) and iGEMRIC techniques were interchanged with MR imaging. For dGEMRIC, a double routine dose of Gd-DTPA^2- (0.2 mM/kg) was administered intravenously. For iGEMRIC, 2.5 and 1.25 mmol/l saline-diluted Gd-DTPA^2- solutions were separately injected into the right and left knee joints, respectively, prior to MR imaging. Color-coded T1 maps of 20 femoral condyles were obtained from the dGEMRIC and iGEMRIC images. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and glycosaminoglycan (GAG) delineation of articular cartilage were compared between the dGEMRIC and iGEMRIC techniques.

Results: The mean SNR was higher with dGEMRIC than with iGEMRIC, but the difference was not statistically significant (P = 0.174). The mean (±SD) CNR was higher with iGEMRIC (-11.6±3.4) than with dGEMRIC (-16.7±4.0; P = 0.000), although the absolute value of the CNR was higher with dGEMRIC. The layering and gradient distribution of GAG were more clearly visualized on the iGEMRIC images. The mean scores of GAG delineation with dGEMRIC and iGEMRIC were 0.7±0.6 and 2.2±1.7, respectively. The iGEMRIC method better visualized GAG distribution (P = 0.001).

Conclusion: Although the SNR did not differ significantly between the iGEMRIC and dGEMRIC techniques, the color-coded T1 map produced with iGEMRIC allowed better cartilage evaluation. Thus, iGEMRIC exhibits the useful features of both MR arthrography and dGEMRIC, and provides a color-coded T1 map that is useful for diagnosing early articular cartilage damage.     

Malignant esophageal-tracheobronchial strictures: parallel placement of covered retrievable expandable nitinol stents

Purpose: To assess the safety and clinical effectiveness of the parallel placement of covered retrievable expandable metallic stents in the palliative treatment of malignant esophageal and tracheobronchial strictures.

Material and Methods: Under fluoroscopic guidance, parallel stents were placed in 12 symptomatic patients with both malignant esophageal and tracheobronchial strictures. Seven of these 12 patients also had an esophagorespiratory fistula (ERF) and one patient had an esophagocutaneous fistula. Technical success, clinical improvement, complications, and survival rates were evaluated.

Results: A total of 28 esophageal and airway stents were successfully placed. The grade of dysphagia and dyspnea score significantly decreased after stent placement (P = 0.002 and 0.003, respectively). ERF and esophagocutaneous fistula were sealed off in all eight patients after esophageal stent placement; however, the esophagocutaneous fistula reopened 1 month later. Complications included stent migration or expectoration (n = 3), tracheal compression by the esophageal stent (n = 3), new fistula development due to covering membrane degradation of the esophageal stent (n = 1), and symptomatic sputum retention (n = 1). Stent removal was easily performed for two stents; one migrated stent and the other with covering membrane degradation. All 12 patients died within the mean survival period of 72.50 days (range 7-375 days).

Conclusion: Parallel placement of covered retrievable expandable metallic stents is safe and effective for the palliative treatment of malignant esophageal and tracheobronchial strictures.     

Multidetector computed tomography in acute knee injuries: assessment of cruciate ligaments with magnetic resonance imaging correlation

Purpose: To evaluate whether non-contrast multidetector computed tomography (MDCT) for suspected acute knee fractures can also be used to evaluate cruciate ligament pathology.

Material and Methods: A total of 42 patients (17-65 years) underwent four-section MDCT. The images were independently evaluated at clinical workstations by four radiologists. They assessed the integrity (normal or torn) and the best slice direction (axial, sagittal, or coronal) for visualization of the cruciate ligaments. Magnetic resonance imaging (MRI), performed within 4 weeks (mean 6 days) in relation to MDCT, was considered the gold standard.

Results: Ligament integrity at MDCT: the mean interobserver proportion of agreement for a normal anterior cruciate ligament (ACL) was 0.73, for a torn ACL 0.41, for a normal posterior cruciate ligament (PCL) 0.96, and for a torn PCL 0.54. Interobserver variation for ACL was significant (P = 0.0136-0.0260), but insignificant for PCL (P = 0.3389-0.7212). Intra-observer variation was insignificant. Visualization was best in the axial and sagittal direction for ACL and PCL, respectively. At MRI, 29 normal, one partially, and 12 completely torn ACLs, and 37 normal, four partially and one completely torn PCL were found.

Conclusion: MDCT can detect an intact ACL and PCL with good specificity, accuracy, and negative predictive value. The assessment of torn ligaments is unreliable.     

Needle tract seeding after vacuum-assisted breast biopsy

Background: A matter of substantial concern regarding all needle biopsy techniques is seeding along the biopsy needle tract.

Purpose: To assess cell seeding along the needle tract of vacuum-assisted breast biopsy (VABB).

Material and Methods: The study included 21 patients with ductal carcinoma in situ (DCIS) and 10 patients with invasive ductal carcinoma (IDC) diagnosed by VABB for nonpalpable mammographic lesions. VABB (11G, on a Fischer table) was performed, and the duration of the procedure was measured. After surgery, the whole needle tract was embedded in paraffin blocks, stained with hematoxylin-eosin, and examined by a pathologist.

Results: Cases with dissemination of cancer cells in the needle tract were not observed (one-sided 97.5% CI 0-10.0%). In 2/31 (6.5%) cases (95% CI 0.8-21.4%), benign epithelial cell displacement was observed, and the duration of VABB was significantly longer in these two cases (52.5±3.5 min vs. 42.0±4.4 min for cases without benign cell displacement; P = 0.018, Mann-Whitney-Wilcoxon test for independent samples).

Conclusion: No displacement of malignant cells within the 11G needle tract was documented. Benign cell displacement was associated with longer VABB duration. The phenomenon of tumor cell dissemination along the needle tract is of questionable clinical significance when the treatment guidelines are followed.     

Learning curve for add-on stereotactic core needle breast biopsy

Purpose: To evaluate the learning curve for an add-on 14 G stereotactic core needle biopsy (SCNB).

Material and Methods: A total of 231 non-palpable breast lesions that had undergone add-on SCNB were evaluated in this prospective study. Five radiologists performed their first three biopsies under supervision. Subsequent, independently performed, biopsies were also evaluated. The samples were collected in three different containers: the first sample in container A, the second and third samples in container B, and subsequent samples in container C (available for four radiologists from the first biopsy on). Technically successful biopsies and false-negative rate in three container combinations (A, A+B, A+B+C) were reported as a function of operator experience.

Results: Technically unsuccessful biopsies occurred significantly more often in microcalcifications than in masses (14.9% versus 3.8%; P = 0.04). For microcalcifications, the rate of successful biopsies was 75% (18/24) for the first 5 biopsies and 87.8% (79/90) for the subsequent biopsies (P = 0.335); rates for the masses were 95.7% (22/23) and 96.3% (79/82) (P = 1.0), respectively. A tendency was noted for the false-negative rate to be higher for the first five biopsies in three container combinations than in subsequent cases.

Conclusion: Our results support the existence of a learning curve, especially in the biopsy of microcalcifications. More than three mentor-guided biopsies are needed.     

Cost-effectiveness of computed tomographic colonography: a prospective comparison with colonoscopy

Purpose: To estimate the cost-effectiveness of detecting colorectal polyps with computed tomographic colonography (CTC) and subsequent polypectomy with primary colonoscopy (CC), using CC as the alternative strategy.

Material and Methods: A marginal analysis was performed regarding 103 patients who had had CTC prior to same-day CC at two hospitals, H-I (n = 53) and H-II (n = 50). The patients were randomly chosen from surveillance and symptomatic study populations (148 at H-I and 231 at H-II). Populations, organizations, and procedures were compared. Cost data on time consumption, medication, and minor equipment were collected prospectively, while data on salaries and major equipment were collected retrospectively. The effect was the (previously published) sensitivities of CTC and CC for detection of colorectal polyps≥6 mm (H-I, n = 148) or ≥5 mm (H-II, n = 231).

Results: Thirteen patients at each center had at least one colorectal polyp≥6 mm or ≥5 mm. CTC was the cost-effective alternative at H-I (€187 vs. €211), while CC was the cost-effective alternative at H-II (€239 vs. €192). The cost-effectiveness (costs per finding) mainly depended on the sensitivity of CTC and CC, but the depreciation of equipment and the staff's use of time were highly influential as well.

Conclusion: Detection of colorectal polyps≥6 mm or ≥5 mm with CTC, followed by polypectomy by CC, can be performed cost-effectively at some institutions with the appropriate hardware and organization.     

Magnetic resonance imaging in the assessment of cystic pancreatic lesions: differentiation of benign and malignant lesion status

Purpose: To characterize cystic pancreatic lesions and tumors with magnetic resonance imaging (MRI), and to assess the value of morphological criteria in differentiating pseudocysts versus cystic tumors and benign versus malignant cystic tumors.

Material and Methods: Twenty-three patients with cystic pancreatic tumors or lesions underwent plain and contrast-material-enhanced MRI, including magnetic resonance cholangiopancreatography (MRCP). The MR findings were characterized and analyzed by two readers, and the role of various imaging criteria and combinations thereof for final lesion assignment were assessed. Final diagnoses were obtained from the results of open surgery (n = 19) and/or biopsy (n = 4).

Results: Final diagnoses included cystic tumors (n = 11) and pseudocysts (n = 12). The lesions were located in the head (56%) and body or tail (44%). Lesion diameters ranged from 7 to 50 mm. Various lesion contrast enhancement patterns were observed for both benign and malignant lesions. Serous cystadenomas were located in the head, they were lobulated, and had wall diameters≤2 mm; with the combination of these characteristics all patients with serous cystadenoma could be identified, whereas in no other patient was this constellation observed.

Conclusion: MRI facilitated the diagnosis of serous cystadenomas, although no definite morphologic criterion for the differentiation between pseudocysts and mucinous cystadenomas was identified. In consideration of the substantial therapeutic consequences, either diagnostics in unclear cystic pancreatic lesions should comprise cyst fluid analysis if necessary, or eligible patients should be referred for surgical resection.