Israel Medical Association Journal

Background: Magnetic resonance imaging is a diagnostic tool of growing importance. Since its introduction, certain medical implants, e.g., pacemakers, were considered an absolute contraindication, mainly due to the presence of ferromagnetic components and the potential for electromagnetic interference. Patients with such implants were therefore prevented from entering MRI systems and not studied by this modality. These devices are now smaller and have improved electromechanical interference protection. Recently in vitro and in vivo data showed that these devices may be scanned safely in the MRI.

Objectives: To report our initial experience with three patients with pacemakers who underwent cerebral MRI studies.

Methods: The study included patients with clear clinical indications for MRI examination and who had implanted devices shown to be safe by in vitro and in vivo animal testing. In each patient the pacemaker was programmed to pacing-off. During the scan, continuous electrocardiographic telemetry, breathing rate, pulse oximetry and symptoms were monitored. Specific absorption rate was limited to 4.0 W/kg for all sequences. Device parameters were assessed before, immediately after MRI, and 1 week later.

Results: None of the patients was pacemaker dependent. During the MRI study, no device movement was felt by the patients and no episodes of inappropriate inhibition or rapid activation of pacing were observed during the scan. At device interrogation here were no significant differences in device parameters pre-, post-, and 1 week after MRI. Image quality was unremarkable in all imaging sequences used and was not influenced by the presence of the pacemaker.

Conclusion: Given appropriate precautions, MRI can be safely performed in patients with a selected permanent pacemaker. This may have significant implications for current MRI contraindications.  

Objectives: To establish the impact of breast MRI on women undergoing testing in our institution.

Methods: We analyzed 82 cases that underwent MRI between January 2001 and April 2003. Analysis appraised the clinical impact of MRI testing in cases where medical summaries were available.

Results: Studies were categorized into five indications: a) screening in high risk women (n=7), b) search for primary disease in the presence of disease (n=5), c) monitoring of chemotherapy (n=2), d) postoperative assessment of tumor bed (n=9), and e) diagnostic/characterization of primary or recurrent breast cancer (n=59). Results were defined as negative, positive or no impact on clinical management. MRI testing had a positive impact in 62 cases, affecting measurable change in 9 cases. Benefit was seen in screening, diagnosis and postoperative cases. In 15 cases, MRI stimulated investigations.

Conclusion: MRI is a valuable tool in breast imaging and affects management. Further trials are necessary to define clearly the role of MRI and to ascertain whether in cases where beneficial impact on management is noted, there is ultimate impact on outcome. 

Objectives: To compare the subjective visibility of normal anatomic landmarks in the chest on storage phosphor-based digital radiographs versus conventional screen-film radiographs.

Methods: Digital phosphor-based and screen-film posteroanterior chest radiographs were obtained during 1 year in 140 asymptomatic patients without any known pulmonary disease (119 men, 21 women; mean age 52.1 years, range 23–86). Both sets of films were independently compared by two experienced radiologists in different sessions. The visibility of each of the following anatomic landmarks was graded from 1 to 3: pulmonary fissures, carina, bronchi to left upper lobe, right upper lobe and left lower lobe, bronchus intermedius, anterior and posterior junctional lines, and vessels behind the heart and diaphragm. Additionally, subjective general quality impression of each radiograph was graded similarly. Statistical analyses were performed using the chi-square test. A P value less than 0.05 was considered significant.

Results: Visibility with the digital images was statistically significantly higher for the carina, left lower lobe bronchus, bronchus intermedius, and vessels behind the heart and diaphragm. Subjective general quality impression of digital radiographs was also higher (P < 0.001). No significant visibility differences were found for pulmonary fissures or junctional lines.

Conclusion: Subjective visibility of anatomic structures behind the heart and diaphragm and at the hilae is significantly improved with phosphor-based digital radiography compared with conventional screen-film radiography. This suggests that pathologic processes such as pulmonary nodules, masses or consolidations projected over those structures may be more easily and reliably depicted on digital than conventional chest X-rays.

Objectives: To investigate the spectrum of findings in 32 consecutive patients with chest pain who underwent CT coronary angiogram in order to determine the clinical situations that will benefit most from this new technique.

Methods: Thirty-two patients with chest pain were studied by MDCT[1] using 4 x 1 mm cross-sections, at 500 msec rotation with pitch 1–1.5, intravenous non-ionic contrast agent and a retrospectively ECG-gated reconstruction algorithm. The heart anatomy was evaluated using multi-planar reconstructions in the axial, long and short heart axes planes. Coronary arteries were evaluated using dedicated coronary software and the results were compared to those of the conventional coronary angiograms in 12 patients. The patients were divided into four groups according to the indication for the study: group A – patients with high probability for coronary disease; group B – patients after CCA[2] with undetermined diagnosis; group C – patients after cardiac surgery with possible anatomic derangement; and group D – symptomatic patients after coronary artery bypass graft, before considering conventional coronary angiography.

Results: Artifacts caused by coronary motion, heavy calcification and a lumen diameter smaller than 2 mm were the most frequent reasons for non-evaluable arteries. Assessment was satisfactory in 83% of all coronary segments. The overall sensitivity of 50% stenosis was 74% (85% for main vessels) with a specificity of 96%. Overall, the CTCA[3] results were critical for management in 18 patients.

Conclusions: Our preliminary experience suggests that CTCA is a reliable and promising technique for the detection of coronary artery stenosis as well as for a variety of additional cardiac and coronary structural abnormalities.

Background: Involvement of the liver by lymphoma is almost always secondary. A definite diagnosis can be made only after histologic examination. Recently, there has been a trend to replace surgical biopsies with percutaneous core-needle biopsies for the diagnosis of lymphoproliferative disorders.

Objectives: To describe our experience with percutaneous image-guided needle biopsies of the liver in 15 cases of primary and secondary hepatic lymphoma.

Methods: Between 1997 and 2002, 15 of all the percutaneous computerized tomography-guided core-needle liver biopsies performed at our institution yielded the diagnosis of lymphoma. We retrospectively reviewed the medical records of these patients.

Results: Seven patients had primary hepatic lymphoma (all non-Hodgkin’s lymphoma), and eight had secondary (three Hodgkin`s disease and five non-Hodgkin’s lymphoma). No major complications were caused by the percutaneous biopsies, and all biopsies were diagnostic. The imaging findings were non-specific but were characteristic and similar to previously described series. Imaging demonstrated hypodense lesions by CT, or hypoechoic or anechoic lesions by ultrasound in all but two cases in which hilar lesions resulted in biliary dilatation, both demonstrated by ultrasound

Conclusions: Review of our primary cases indicated no association with cirrhosis or AIDS in contradistinction to the worldwide experience. There were no significant complications in the 15 patients in the study, and a definite diagnosis of lymphoma was made in all the cases with no need to proceed to surgical biopsy. We highly recommend image-guided core-needle biopsy of the liver as a reliable and useful tool for the diagnosis of hepatic lymphoma.

Israel has a National Screening Program for early detection of breast cancer. The need to continue and even expand this program was recently stressed in light of the high risk in the population. However, the optimal modalities for breast cancer screening are controversial, especially for women at risk. Mammography, the established screening method, is critically examined, and molecular imaging techniques, such as magnetic resonance spectroscopy and spectroscopic imaging are explored, especially for primary breast cancer detection. MRS[1] and MRSI[2] are currently limited by their reliance on the conventional framework for data analysis in biomedical imaging, i.e., the fast Fourier transform. Recent mathematical advances in signal processing via the fast Pade transform can extract diagnostically important information, which until now has been unavailable with in vivo MRS. A clinical MRS signal illustrates the rapid and stable convergence provided by FPT[3], yielding accurate information about key metabolites and their concentrations at short acquisition times. We suggest that the next step would be to apply the FPT to in vivo MRS/MRSI signals from patients with breast cancer and to compare these to findings for normal breast tissue. The potential implications of such an optimized MRS/MRSI for breast cancer screening strategies are discussed, especially for younger women at high risk.

Gadolinium-based agents are widely used in magnetic resonance imaging as contrast agents. These agents are radio-opaque enough for diagnostic imaging of the vascular tree by using digitally subtracted images as well as for imaging of the biliary system and the urinary tract. The recommended doses for gadolinium do not impair renal function or cause adverse reactions in patients with iodine sensitivity; thus patients with such conditions can safely undergo diagnostic angiography, either by MRI angiography or by catheterization using gadolinium as contrast agent, for diagnostic and therapeutic purposes.

Background: Hypertrophic pyloric stenosis classically presents as projectile vomiting during the third to fourth week of life associated with good appetite. Additional classical presenting findings include palpation of the pyloric tumor, described as olive-shaped, a visible gastric peristaltic wave after feeding, and hypochloremic, hypokalemic metabolic alkalosis. It was recently claimed that this presentation has changed due to the easier access to gastrointestinal imaging.

Objective: To validate this contention and discuss possible reasons.

Methods: We conducted a retrospective chart review of all patients who underwent pyloromyotomy for HPS[1] between 1990 and 2000. Only patients with confirmed HPS at the time of surgery were included. We also performed a comprehensive review of older studies for comparison.

Results: Seventy patients underwent pyloromyotomy over the 10 year period. Overall, 81% of patients were male infants and the mean age at diagnosis was 40 days. The mean duration of symptoms was 8 days. A firstborn child was noted in 43% of the cases. The classical symptom of projectile vomiting was absent in one-third of the patients, a pyloric tumor was not palpated in one-half of the cases, bicarbonate was higher than 28 mEq/L in 20% and a pH of above 7.45 was present in 25% of patients. Hypochloremia was noted in about one-third. We found a good correlation between ultrasonographic width and length of the pylorus and the intraoperative findings. Pylorus length ≥ 24 mm correlated with significantly longer duration of symptoms. When compared with previous studies, the main findings were not significantly different; namely, mean age at diagnosis, percentage of male gender and duration to diagnosis. The decrease in the number of pyloric tumors palpated paralleled the increase in the use of upper gastrointestinal series and ultrasonography in particular.

Conclusions: The clinical presentation of HPS has not actually changed despite the easier accessibility of GI imaging studies. However, the one significant change is the low percentage of pyloric tumors palpated, probably due to declining clinical skills, accompanied by earlier utilization of imaging studies. The use of imaging and laboratory studies did not change the age at diagnosis but may have shortened the time for diagnosis and reduced the postoperative stay. Imaging and laboratory studies may be helpful for the subgroup with a non-classical clinical presentation.

Background: Technetium-99m sestamibi scintigraphy has become one of the most popular techniques for localization of the parathyroid gland after failure of primary neck exploration.

Objective: To examine the efficacy of sestamibi with the hand-held gamma ray detecting probe for the identification of parathyroid adenomas during revision parathyroidectomy.

Methods: We reviewed six cases of probe-assisted neck exploration for parathyroid lesions following unsuccessful primary exploration.

Results: In all cases, the pathologic glands were successfully detected and removed.

Conclusions: With careful planning, a gamma ray detecting probe can be used optimally at 2–3 hours after technetium-99m sestamibi injection. The probe is efficient, easy and convenient to use.